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Research to Practice 2016 Melbourne AU + ('''Research to Practice 2016, Melbourne, Victoria, AU; [http://researchtopractice2016.com.au Research to Practice 2016].''')
New Frontiers in Cardiovascular Research 2016 Singapore SG + ('''Research to Practice 2016, Singapore, SG''')
SFRR Australasia 2016 Gold Coast AU + ('''SFRR Australasia 2016, Gold Coast, AU; [http://www.sfrra2016.org/overview.php SFRR Australasia 2016].''')
SFRR-E 2016 Budapest HU + ('''SFRR-E 2016, Budapest, HU; [http://sfrr-e-2016.hu/ SFRR-E 2016].''')
IOC166 Ljubljana SI + ('''Satellite symposium and workshop "Skeletal Muscle Research – from Cell to Human"'''. Ljubljana, Slovenia (2024 Sep 26). )
MiPNet06.01 O2k-Overview + ('''Summary:''' The Oroboros O2k provides t … '''Summary:''' The Oroboros O2k provides the instrumental basis for high-resolution respirometry. Compared to any of its competitors, the Oroboros O2k is a high-performance instrument, and high-resolution is distinguished from conventional approaches by a combination of unique features and specifications. These set a new standard in bioenergetics, mitochondrial physiology, clinical research and diagnosis of mitochondrial pathologies.nd diagnosis of mitochondrial pathologies.)
MiPNet10.09 MiP2005 + ('''Summary:''' Whereas isolated mitochondr … '''Summary:''' Whereas isolated mitochondria remain one of the gold-standards in studies of bioenergetics and mitochondrial physiology, permeabilized tissues and cells have become an alternative with several advantages. But some disadvantages have to be considered, too, for optimum experimental design and critical evaluation of results.design and critical evaluation of results.)
CSH Asia 2017 Suzhou CN + ('''The Cold Spring Harbor Asia conference on Mitochondria'''. Suzhou, China; 2017 October.)
MiPNet07.01 Advances + ('''The [[Oroboros O2k]] … '''The [[Oroboros O2k]] with [[DatLab]] software is the sole-source instrument for [[high-resolution respirometry]] (HRR), with the option of modular [[O2k-MultiSensor]] extension and electronically controlled [[Titration-Injection microPump]] (TIP2k), and accessories including the [[ISS-Integrated Suction System\230 V\EU]] (ISS) and titration syringes.'''[[ISS-Integrated Suction System\230 V\EU]] (ISS) and titration syringes.''')
Mickevicius 2016 Thesis + ('''The aim of this research:''' To investi … '''The aim of this research:''' To investigate an effect of short time ischemia/reperfusion ''in vivo'' on rat kidney mitochondria oxidative phosphorylation.'''Objectives:''' To evaluate the effect of 20 min ischemia and 30 min reperfusion on mitochondria oxidative phosforilation system and investigate rat mitochondrial respiration chain complex I, II and II + III activity.'''Object of this research:''' Wistar breed rats males were used to perform this research.'''Methods:''' Warm ischemia (37 ° C) to rat kidneys was induced by clamping renal arteries using vascular clamps. Ischemia was induced for 20 min and after that reperfusion lasted for 30 min. Kidneys were removed and mitochondria were isolated by using differential centrifugation method. The amount of proteins was measured via Buret method. Mitochondrial respiration rates were measured by Oxygraph-2k system and using glutamate/malate and succinate as substrates. Mitochondrial respiration chain complexes activity was measured spectrophotometrically.'''Results:''' This research results show that short time (20 min) ischemia and reperfusion (30 min) does not affect the respiration rates when mitochondrial respiration chain complex I substrate glutamate/malate is being oxidized. This research shows that oxidizing mitochondrial respiration chain complex II substrate succinate evaluates respiration rate in state two after short-time ischemia 1.47 times but didn’t affect state three. Oxidizing succinate respiration control index decreases by 22 % which show that even after short-time ischemia mitochondrial membrane is getting damaged. Complex I activity decreased by 67% after 20 min ischemia and 30 min reperfusion.'''Conclusions:''' Research showed that even short time of ischemia damages mitochondrial oxidative phosphorylation system. Short-time ischemia decreases mitochondrial respiration chain complex I.mitochondrial respiration chain complex I.)
Tar 2014 J Biol Chem + ('''This manuscript was withdrawn by the au … '''This manuscript was withdrawn by the author!'''The conserved Blm10/PA200 activators bind to the proteasome core particle gate and facilitate turnover of peptides and unfolded proteins ''in vitro''. We report here that Blm10 is required for the maintenance of functional mitochondria. BLM10 expression is induced 25-fold upon a switch from fermentation to oxidative metabolism. In the absence of BLM10 Saccharomyces cerevisiae cells exhibit a temperature-sensitive growth defect under oxidative growth conditions and produce colonies with dysfunctional mitochondria at high frequency. Loss of BLM10 leads to reduced respiratory capacity, increased mitochondrial oxidative damage and reduced viability in the presence of oxidative stress or death stimuli. In the absence of BLM10 increased fragmentation of the mitochondrial network under oxidative stress is observed indicative of elevated activity of the mitochondrial fission machinery. The degradation of Dnm1, the main factor mediating mitochondrial fission, is impaired in the absence of BLM10 ''in vitro'' and ''in vivo''. These data suggest that the mitochondrial functional and morphological changes observed are related to elevated Dnm1 levels. This hypothesis is supported by the finding that cells that constitutively overexpress DNM1, display the same mitochondrial defects as blm10Δ cells. The data are consistent with a model in which Blm10-proteasome mediated turnover of Dnm1 is required for the maintenance of mitochondrial function and provides cytoprotection under conditions that induce increased mitochondrial damage and programmed cell death.hondrial damage and programmed cell death.)
MiPNet14.10 O2k-Top 10 + ('''We summarize 10 compelling reasons for choosing the Oroboros O2k, for collaborating in the Oroboros Ecosystem, and for spreading our reproducibility committment. ‘Top 10’ reflects our corporate goals.''')
Schiemer 2018 Schriften + ('''Wolfgang Wieser (1924–2017) – a central … '''Wolfgang Wieser (1924–2017) – a central force in Austrian biology.'''The most important stages in Wolfgang Wieser’s life and scientific career are illustrated in this paper. Wolfgang Wieser was a central personality in Austrian biology. His contributions to the development of an eco-physiological approach are outlined, including his books on evolutionary biology, especially in context of the cultural development of mankind.xt of the cultural development of mankind.)
IOC48 + ('''Workshop at the 5th Meeting of ASMRM Jo … '''Workshop at the 5th Meeting of ASMRM Jointly with Chinese Mit'2008 Tianjin University of Sport.''' Tianjin , China; 2008 November 09.:>> O2k-Workshop: [[Oroboros Events| Current dates]]:>> Product: [[Oroboros O2k]], [[Oroboros O2k-Catalogue | O2k-Catalogue]][[Oroboros O2k-Catalogue | O2k-Catalogue]])
MiPNet19.16 IOC98 + ('''[[File:Sunpoint Hsu Gnaiger Tsai Lu.JPG|right|500px|thumb|[[Hsu A| Ari Hsu]] … '''[[File:Sunpoint Hsu Gnaiger Tsai Lu.JPG|right|500px|thumb|[[Hsu A| Ari Hsu]], [[Gnaiger E| Erich Gnaiger]], [[Tsai S| Sunny Tsai]] and [[Lu A| Amelia Lu]] (left to right) in the Sunpoint Office at IOC98.''']][[Image:O2k-Workshops.png|left|130px|link=http://www.oroboros.at/?O2k-Workshops]]'''98th OROBOROS O2k-Workshop on high-resolution respirometry and O2k-Fluorometry'''lution respirometry and O2k-Fluorometry''')
Gnaiger IOC62-Introduction + ('''[[High-resolution respirometry]]''' (HRR) provides a quantitative approach to bioenergetics and mitochondrial physiology with the [[Oroboros O2k]] (Oroboros Instruments) offering several sole-source features.)
MitoFit Open Seminar 2017-07-14 + ('''[[Karabatsiakis 2017 MitoFit Open Seminar|MitoFit Open Seminar on immune cell bioenergetics]]'''. Innsbruck, AT)
Leuner 2012 Antioxid Redox Signal + (''AIMS'' Intracellular amyloid beta (Aβ) o … ''AIMS'' Intracellular amyloid beta (Aβ) oligomers and extracellular Aβ plaques are key players in the progression of sporadic Alzheimer's disease (AD). Still, the molecular signals triggering Aβ production are largely unclear. We asked whether mitochondrion-derived reactive oxygen species (ROS) are sufficient to increase Aβ generation and thereby initiate a vicious cycle further impairing mitochondrial function.''RESULTS'' Complex I and III dysfunction was induced in a cell model using the respiratory inhibitors rotenone and antimycin, resulting in mitochondrial dysfunction and enhanced ROS levels. Both treatments lead to elevated levels of Aβ. Presence of an antioxidant rescued mitochondrial function and reduced formation of Aβ, demonstrating that the observed effects depended on ROS. Conversely, cells overproducing Aβ showed impairment of mitochondrial function such as comprised mitochondrial respiration, strongly altered morphology, and reduced intracellular mobility of mitochondria. Again, the capability of these cells to generate Aβ was partly reduced by an antioxidant, indicating that Aβ formation was also ROS dependent. Moreover, mice with a genetic defect in complex I, or AD mice treated with a complex I inhibitor, showed enhanced Aβ levels ''in vivo''.''INNOVATION'' We show for the first time that mitochondrion-derived ROS are sufficient to trigger Aβ production ''in vitro'' and ''in vivo''.''CONCLUSION'' Several lines of evidence show that mitochondrion-derived ROS result in enhanced amyloidogenic amyloid precursor protein processing, and that Aβ itself leads to mitochondrial dysfunction and increased ROS levels. We propose that starting from mitochondrial dysfunction a vicious cycle is triggered that contributes to the pathogenesis of sporadic AD.ibutes to the pathogenesis of sporadic AD.)
Stride 2013 Eur J Heart Fail + (''AIMS'': Heart failure (HF) with left ven … ''AIMS'': Heart failure (HF) with left ventricular systolic dysfunction (LVSD) is associated with a shift in substrate utilization and a compromised energetic state. Whether these changes are connected with mitochondrial dysfunction is not known. We hypothesized that the cardiac phenotype in LVSD could be caused by reduced mitochondrial oxidative phosphorylation (OXPHOS) capacity and reduced mitochondrial creatine kinase (miCK) capacity. The study aim was to test mitochondrial OXPHOS capacity in LVSD myocardium compared with OXPHOS capacity in a comparable patient group without LVSD.''METHODS AND RESULTS'': Myocardial biopsies were obtained from the left ventricle during cardiac valve or left ventricular assist device (LVAD) surgery. Patients were stratified according to left ventricular ejection fraction (LVEF) into LVSD (LVEF <45%, n = 14) or CONTROL (LVEF >45%, n = 15). Mitochondrial respiration was measured in muscle fibres with addition of non-fatty acid substrates or octanoyl-l-carnitine, a medium chain fatty acid (MCFA). The ''in situ'' enzyme capacity of miCK was determined from APD titrations in the presence or absence of creatine. Maximal OXPHOS capacity with non-fatty acid substrates was lower in the LVSD group compared with the CONTROL group (P ≤ 0.05). ADP sensitivity always increased significantly (P ≤ 0.05) with the addition of creatine, after which the sensitivity was highest (P ≤ 0.05) in LVSD compared with CONTROL. The stimulation of OXPHOS from octanoyl-l-carnitine titrations elicited ∼40% lower respiration in LVSD compared with CONTROL (P ≤ 0.05).''CONCLUSION'': Human LVSD is associated with markedly diminished OXPHOS capacity, particularly in MCFA oxidation. This offers a candidate mechanism for a compromised energetic state and decreased reliance on fatty acid utilization in HF.reased reliance on fatty acid utilization in HF.)
Lou 2013 Cardiovasc Res + (''AIMS'': Infarct-remodelled hearts are le … ''AIMS'': Infarct-remodelled hearts are less amenable to protection against ischaemia/reperfusion. Understanding preservation of energy metabolism in diseased vs. healthy hearts may help to develop anti-ischaemic strategies effective also in jeopardized myocardium.''METHODS AND RESULTS'': Isolated infarct-remodelled/sham Sprague-Dawley rat hearts were perfused in the working mode and subjected to 15 min of ischaemia and 30 min of reperfusion. Protection of post-ischaemic ventricular work was achieved by pharmacological conditioning with sevoflurane. Oxidative metabolism was measured by substrate flux in fatty acid and glucose oxidation using [(3)H]palmitate and [(14)C]glucose. Mitochondrial oxygen consumption was measured in saponin-permeabilized left ventricular muscle fibres. Activity assays of citric acid synthase, hydroxyacyl-CoA dehydrogenase, and pyruvate dehydrogenase and mass spectrometry for acylcarnitine profiling were also performed. Six weeks after coronary artery ligation, the hearts exhibited macroscopic and molecular signs of hypertrophy consistent with remodelling and limited respiratory chain and citric acid cycle capacity. Unprotected remodelled hearts showed a marked decline in palmitate oxidation and acetyl-CoA energy production after ischaemia/reperfusion, which normalized in sevoflurane-protected remodelled hearts. Protected remodelled hearts also showed higher β-oxidation flux as determined by increased oxygen consumption with palmitoylcarnitine/malate in isolated fibres and a lower ratio of C16:1+C16OH/C14 carnitine species, indicative of a higher long-chain hydroxyacyl-CoA dehydrogenase activity. Remodelled hearts exhibited higher PPARα-PGC-1α but defective HIF-1α signalling, and conditioning enabled them to mobilize fatty acids from endogenous triglyceride stores, which closely correlated with improved recovery.''CONCLUSIONS'': Protected infarct-remodelled hearts secure post-ischaemic energy production by activation of β-oxidation and mobilization of fatty acids from endogenous triglyceride stores.acids from endogenous triglyceride stores.)
Carvalho-Kelly 2020 J Bioenerg Biomembr + (''Acanthamoeba castellanii'' is a free-liv … ''Acanthamoeba castellanii'' is a free-living amoeba and the etiological agent of granulomatous amoebic encephalitis and amoebic keratitis. ''A. castellanii'' can be present as trophozoites or cysts. The trophozoite is the vegetative form of the cell and has great infective capacity compared to the cysts, which are the dormant form that protect the cell from environmental changes. Phosphate transporters are a group of proteins that are able to internalize inorganic phosphate from the extracellular to intracellular medium. Plasma membrane phosphate transporters are responsible for maintaining phosphate homeostasis, and in some organisms, regulating cellular growth. The aim of this work was to biochemically characterize the plasma membrane phosphate transporter in ''A. castellanii'' and its role in cellular growth and metabolism. To measure inorganic phosphate (Pi) uptake, trophozoites were grown in liquid PYG medium at 28 °C for 2 days. The phosphate uptake was measured by the rapid filtration of intact cells incubated with 0.5 μCi of 32Pi for 1 h. The Pi transport was linear as a function of time and exhibited Michaelis-Menten kinetics with a Km = 88.78 ± 6.86 μM Pi and Vmax = 547.5 ± 16.9 Pi × h-1 × 10-6 cells. ''A. castellanii'' presented linear phosphate uptake up to 1 h with a cell density ranging from 1 × 105 to 2 × 106 amoeba × ml-1. The Pi uptake was higher in the acidic pH range than in the alkaline range. The oxygen consumption of living trophozoites increased according to Pi addition to the extracellular medium. When the cells were treated with FCCP, no effect from Pi on the oxygen flow was observed. The addition of increasing Pi concentrations not only increased oxygen consumption but also increased the intracellular ATP pool. These phenomena were abolished when the cells were treated with FCCP or exposed to hypoxia. Together, these results reinforce the hypothesis that Pi is a key nutrient for ''Acanthamoeba castellanii'' metabolism.her, these results reinforce the hypothesis that Pi is a key nutrient for ''Acanthamoeba castellanii'' metabolism.)
Votion 2023 MiP2023 + (''Acer pseudoplatanus'' contains toxins re … ''Acer pseudoplatanus'' contains toxins responsible for poisoning in various species [1], including humans [2]. In equids, this intoxication induces an often fatal rhabdomyolysis syndrome known as atypical myopathy (AM); [3]. Blood analysis reveals a severe metabolic disturbance characterised by hyperglycaemia, high triglycerides, and lipid intermediates [4]. Toxins inhibit several steps of the fatty acid β-oxidation cycle that leads to the accumulation of acyl-CoAs in the mitochondria, which are scavenged into acylcarnitines. Also, competitive inhibition of long-chain fatty acid transport into mitochondria results into their accumulation conjugated with carnitine. In addition, inhibition of the catabolic pathway of branched-chain amino acids, particularly leucine, leads to the accumulation of branched acylcarnitines [2; 5]. Acylcarnitines in tissues may explain parts of the pathophysiological process, such as the cardiac myopathy occurring in AM. Also, acylcarnitines accumulation could promote muscle insulin resistance and contribute to the hyperglycaemia observed in AM horses [4]. The disease also results from severe impairment of mitochondrial bioenergetics [6; 7]. In AM, the serum acylcarnitines profile contributes to the diagnosis of the disease, its prognosis and is also a valuable aid in monitoring ongoing metabolic disturbances. In search of new therapeutic approaches for this environmental intoxication, we are currently designing toxicity assays with cultured cells [7] and zebrafish larvae. These models will help us to test different drugs by exploring their ability to prevent metabolic disturbances as indicated by the acylcarnitines profile. Indeed, in both models, the alteration of the acylcarnitine profile can be followed.# Renaud B et al, (2022) Acer pseudoplatanus: A Potential Risk of Poisoning for Several Herbivore Species. https://doi.org/10.3390/toxins14080512# Tanaka K, Isselbacher KJ, Shih V (1972) Isovaleric and -methylbutyric acidemias induced by hypoglycin A: mechanism of Jamaican vomiting sickness. https://doi.org/10.1126/science.175.4017.69 # Votion DM, Serteyn D (2008) Equine atypical myopathy: a review. https://doi.org/10.1016/j.tvjl.2008.02.004# Boemer F, Detilleux J, Cello C, Amory H, Marcillaud-Pitel C, Richard E, van Galen G, van Loon G, Lefere L, Votion DM (2017) Acylcarnitines profile best predicts survival in horses with atypical myopathy. https://doi.org/10.1371/journal.pone.0182761# Wouters CP et al, (2021) Metabolomic Signatures Discriminate Horses with Clinical Signs of Atypical Myopathy from Healthy Co-grazing Horses. https://doi.org/10.1021/acs.jproteome.1c00225# Lemieux H et al, (2016) Mitochondrial function is altered in horse atypical myopathy. https://doi.org/10.1016/j.mito.2016.06.005 # Kruse CJ, Stern D, Mouithys-Mickalad A, Niesten A, Art T, Lemieux H, Votion DM (2021) In Vitro Assays for the Assessment of Impaired Mitochondrial Bioenergetics in Equine Atypical Myopathy. https://doi.org/10.3390/life11070719e Atypical Myopathy. https://doi.org/10.3390/life11070719 )
Chen 2020 Biochim Biophys Acta Mol Basis Dis + (''Ad libitum'' high-fat diet (HFD) induces … ''Ad libitum'' high-fat diet (HFD) induces obesity and skeletal muscle metabolic dysfunction. Liver kinase B1 (LKB1) regulates skeletal muscle metabolism by controlling the AMP-activated protein kinase family, but its importance in regulating muscle gene expression and glucose tolerance in obese mice has not been established. The purpose of this study was to determine how the lack of LKB1 in skeletal muscle (KO) affects gene expression and glucose tolerance in HFD-fed, obese mice. KO and littermate control wild-type (WT) mice were fed a standard diet or HFD for 14 weeks. RNA sequencing, and subsequent analysis were performed to assess mitochondrial content and respiration, inflammatory status, glucose and insulin tolerance, and muscle anabolic signaling. KO did not affect body weight gain on HFD, but heavily impacted mitochondria-, oxidative stress-, and inflammation-related gene expression. Accordingly, mitochondrial protein content and respiration were suppressed while inflammatory signaling and markers of oxidative stress were elevated in obese KO muscles. KO did not affect glucose or insulin tolerance. However, fasting serum insulin and skeletal muscle insulin signaling were higher in the KO mice. Furthermore, decreased muscle fiber size in skmLKB1-KO mice was associated with increased general protein ubiquitination and increased expression of several ubiquitin ligases, but not muscle ring finger 1 or atrogin-1. Taken together, these data suggest that the lack of LKB1 in skeletal muscle does not exacerbate obesity or insulin resistance in mice on a HFD, despite impaired mitochondrial content and function and elevated inflammatory signaling and oxidative stress.Copyright © 2020. Published by Elsevier B.V.right © 2020. Published by Elsevier B.V.)
Oliveira 2022 Abstract Bioblast-Aedes + (''Aedes aegypti'' females are natural vect … ''Aedes aegypti'' females are natural vectors of important arboviruses including Dengue, Zika and yellow fever. Mosquitoes activate innate immune response signaling pathways upon infection, which target the pathogens and limit their propagation. Despite the beneficial effects of immune activation for insect vectors, there are phenotypic costs that ultimately affect their fitness. However, the underlying mechanisms that mediate these fitness costs remain poorly understood. Given the high energy required to mount a proper immune response, we hypothesized that systemic activation of innate immunity would impair flight muscle mitochondrial function, compromising tissue energy demand and flight activity. Here, we investigated the dynamic effects of activation of innate immunity by intra-thoracic zymosan injection on ''A. aegypti'' flight muscle mitochondrial metabolism. Zymosan injection significantly increased defensin expression in fat bodies in a time-dependent manner and ultimately affecting induced flight activity. Although oxidant levels in flight muscle were hardly altered, [[P-L net OXPHOS capacity |''P''-''L'' net OXPHOS capacity]] ([[OXPHOS capacity |OXPHOS capacity ''P'']] minus [[LEAK respiration |LEAK respiration ''L'']]; ADP→ATP-linked) and [[ET capacity |electron transfer capacity ''E'']] (maximal mitochondrial oxygen consumption rates) supported by pyruvate & proline were significantly reduced at 24 h upon zymosan injection. These effects were parallel to significant and specific reductions in Complex I activity upon zymosan treatment. Finally, the magnitude of defensin up-regulation negatively correlated with maximal, ATP-linked, and NADH&proline-linked respiratory rates ''P'' and ''E'' in flight muscles. Despite strong reductions were observed in proline and [[E-P excess capacity |''E''-''P'' excess capacity]] 24 h upon zymosan injection, this effect was not correlated to the magnitude of innate immune response activation. Collectively, we demonstrate that activation of innate immunity in fat body strongly associates to reduced flight muscle Complex I activity with direct consequences on mitochondrial physiology and dispersal. Remarkably, our results indicate that a trade-off between dispersal and immunity exists in an insect vector, underscoring the potential consequences of disrupted flight muscle mitochondrial energy metabolism on arbovirus transmission.drial energy metabolism on arbovirus transmission.)
Gaviraghi 2019 Anal Biochem + (''Aedes aegypti'' is the most important an … ''Aedes aegypti'' is the most important and widespread vector of arboviruses, including dengue and zika. Insect dispersal through the flight activity is a key parameter that determines vector competence, and is energetically driven by oxidative phosphorylation in flight muscle mitochondria. Analysis of mitochondrial function is central for a better understanding of cellular metabolism, and is mostly studied using isolated organelles. However, this approach has several challenges and methods for assessment of mitochondrial function in chemically-permeabilized tissues were designed. Here, we described a reliable protocol to assess mitochondrial physiology using mechanically permeabilized flight muscle of single ''A. aegypti'' mosquitoes in combination with high-resolution respirometry. By avoiding the use of detergents, high respiratory rates were obtained indicating that substrate access to mitochondria was not limited. This was confirmed by using selective inhibitors for specific mitochondrial substrates. Additionally, mitochondria revealed highly coupled, as ATP synthase or adenine nucleotide translocator inhibition strongly impacted respiration. Finally, we determined that pyruvate and proline induced the highest respiratory rates compared to other substrates tested. This method allows the assessment of mitochondrial physiology in mosquito flight muscle at individual level, and can be used for the identification of novel targets aiming rational insect vector control.Copyright © 2019. Published by Elsevier Inc.right © 2019. Published by Elsevier Inc.)
Lou 2012 Cardiovasc Res + (''Aims:'' Infarct-remodeled hearts are les … ''Aims:'' Infarct-remodeled hearts are less amenable to protection against ischemia-reperfusion. Understanding preservation of energy metabolism in diseased versus healthy hearts may help to develop anti-ischemic strategies also effective in jeopardized myocardium.''Methods and Results:'' Isolated infarct-remodeled/sham Sprague-Dawley rat hearts were perfused in the working mode and subjected to 15 min of ischemia and 30 min of reperfusion. Protection of postischemic ventricular work was achieved by pharmacologic conditioning with sevoflurane. Oxidative metabolism was measured by substrate flux in fatty acid and glucose oxidation using [(3)H]palmitate and [(14)C]glucose. Mitochondrial oxygen consumption was measured in saponin-permeabilized left ventricular muscle fibers. Activity assays of citric acid synthase, hydroxyacyl-CoA dehydrogenase, and pyruvate dehydrogenase and mass spectrometry for acylcarnitine profiling were also performed. Six weeks after coronary artery ligation, hearts exhibited macroscopic and molecular signs of hypertrophy consistent with remodeling and limited respiratory chain and citric acid cycle capacity. Unprotected remodeled hearts showed a marked decline in palmitate oxidation and acetyl-CoA energy production after ischemia/reperfusion, which normalized in sevoflurane-protected remodeled hearts. Protected remodeled hearts also showed higher β-oxidation flux as determined by increased oxygen consumption with palmitoylcarnitine/malate in isolated fibers and a lower ratio of C16:1+C16OH/C14 carnitine species, indicative of a higher long-chain hydroxyacyl-CoA dehydrogenase activity. Remodeled hearts exhibited higher PPARα-[[PGC-1α]] but defective HIF-1α signaling and conditioning enabled them to mobilize fatty acids from endogenous triglyceride store, which closely correlated with improved recovery.''Conclusions:'' Protected infarct-remodeled hearts secure postischemic energy production by activation of β-oxidation and mobilization of fatty acids from endogenous triglyceride stores.acids from endogenous triglyceride stores.)
Furlanetto 2014 Thesis University of Parana + (''Araucaria angustifolia'' is listed as cr … ''Araucaria angustifolia'' is listed as critically endangered by International Union for Conservation of Nature (IUCN) red list of threatened species. The development and propagation of this species is strongly affected by abiotic stress, such as the temperature variation. We previously shown the activation of plant uncoupling mitochondrial protein (PUMP) in embryogenic ''A. angustifolia'' cells submitted to cold stress, an effect associated to oxidative stress. In this work, we advanced in these studies by submitting these cells to cold stress (4 ± 1°C for 24h or 48h) and evaluating the cellular and mitochondrial response associated to oxidative stress, namely: the H2O2 levels, the activity of antioxidant enzymes and lipid peroxidation. In mitochondria from these cells were evaluated the activity of NAD(P)H alternative dehydrogenases and mitochondrial permeability transition (MPT). The cold stress did not affect the morphology and viability of embryogenic ''A. angustifolia'' cells; however, increased the H2O2 levels by ~35% (at 24h and 48h) and lipid peroxidation by ~15% and 30% after 24h and 48h of stress, respectively. The activity of catalase was decreased by ~20% after 48h of cold stress while ascorbate peroxidase (APx) and dehydroascorbate redutase (DHAR) activities were increased by ~100% and ~64%, respectively. For the cells exposition to cold stress by 24h only dehydroascorbate redutase (MDHAR) had the activity increased by ~172%. Glutathione reductase (GR) and superoxide dismutase activities remained unchanged under both stress conditions. In mitochondria, the cold stress promoted a significant inhibition of external alternative NAD(P)H dehydrogenases (~40% at 24h of stress and ~65% at 48h of stress) while the mitochondrial permeability transition (MPT) was slightly inhibited in both, 24h and 48h of stress. The cold stress induces the oxidative stress in embryogenic ''A. angustifolia'' cells, which result in up-regulation of the enzymatic defense mainly the activation of gluthatione-ascorbate cycle in a compensatory way to the inhibition of catalase and external NAD(P)H dehydrogenases. These results contribute to understanding the pathway to overcoming the cold in this gymnosperm and are important for the development of conservation methods of this species such as ''in vitro'' micropropagation.ies such as ''in vitro'' micropropagation.)
Kucera 2012 J Gastroenterol Hepatol + (''BACKGROUND AND AIM'' Acetaminophen overd … ''BACKGROUND AND AIM'' Acetaminophen overdose is the most frequent cause of acute liver failure. Non-alcoholic fatty liver disease is the most common chronic condition of the liver. The aim was to assess whether non-alcoholic steatosis sensitizes rat liver to acute toxic effect of acetaminophen.''METHODS'' Male Sprague-Dawley rats were fed a standard diet (ST-1, 10% kcal fat) and high-fat gelled diet (HFGD, 71% kcal fat) for 6 weeks and then acetaminophen was applied in a single dose (1 g/kg body weight). Animals were killed 24, 48 and 72 h after acetaminophen administration. Serum biochemistry, activities of mitochondrial complexes, hepatic malondialdehyde, reduced and oxidized glutathione, triacylglycerol and cholesterol contents, and concentrations of serum and liver cytokines (TNF-α, TGF-β1) were measured and histopathological samples were prepared.''RESULTS'' The degree of liver inflammation and hepatocellular necrosis were significantly higher in HFGD fed animals after acetaminophen administration. Serum markers of liver injury were elevated only in acetaminophen treated HFGD fed animals. Concentration of hepatic reduced glutathione and ratio of reduced/oxidized glutathione were decreased in both ST-1 and HFGD groups at 24 h after acetaminophen application. Mild oxidative stress induced by acetaminophen was confirmed by measurement of malondialdehyde. Liver content of TNF-α was not significantly altered, but hepatic TGF-β1 was elevated in acetaminophen treated HFGD rats. We did not observe acetaminophen-induced changes in activities of respiratory complexes I, II, and IV and activity of caspase-3.''CONCLUSION'' Liver from rats fed HFGD is more susceptible to acute toxic effect of acetaminophen, compared to non-steatotic liver.minophen, compared to non-steatotic liver.)
Cumero 2012 Br J Pharmacol + (''Background & Purpose'': T1AM is a th … ''Background & Purpose'': T1AM is a thyronamine derivative of thyroid hormone acting as a signalling molecule via non-genomic effectors and can reach intracellular targets. In light of the importance of F0F1-ATPsynthase as a target in drug development, T1AM interaction with the enzyme is demonstrated by its effects on the activity and a model of binding locations is depicted.''Experimental Approach'': Kinetic analyses were performed on F0F1-ATPsynthase in sub-mitochondrial particles and soluble F1-ATPase. Activity assays and immunodetection of the inhibitor protein IF1 were used and combined with molecular docking analyses. ''In situ'' respirometric analysis of T1AM effect was investigated on H9c2 cardiomyocytes.''Key Results'': T1AM is a non-competitive inhibitor of F0F1-ATPsynthase whose binding is mutually exclusive with that of the inhibitors IF1 and aurovertin B. Distinct T1AM binding sites are consistent with results from both kinetic and docking analyses: at low nanomolar concentrations, T1AM binds to a high affinity-region likely located within the IF1 binding site, causing IF1 release; at higher concentrations, T1AM binds to a low affinity-region likely located within the aurovertin binding cavity and inhibits enzyme activity. Low nanomolar concentrations of T1AM elicit in cardiomyocytes an increase in ADP-stimulated mitochondrial respiration indicative for an activation of F0F1-ATPsynthase consistent with displacement of endogenous IF1, thereby reinforcing the ''in vitro'' results.''Conclusions & Implications'': The T1AM effects upon F0F1-ATPsynthase are twofold: IF1 displacement and enzyme inhibition. By targeting F0F1-ATPsynthase within mitochondria T1AM might affect cell bioenergetics with a positive effect on mitochondrial energy production at low endogenous concentration. T1AM putative binding locations overlapping with IF1 and aurovertin binding sites are depicted.lt;/sub>-ATPsynthase within mitochondria T1AM might affect cell bioenergetics with a positive effect on mitochondrial energy production at low endogenous concentration. T1AM putative binding locations overlapping with IF1 and aurovertin binding sites are depicted.)
Usui 2012 Eur J Anaes + (''Background and Goal of Study'': Anesthet … ''Background and Goal of Study'': Anesthetics have been demonstrated to inhibit mitochondrial function in animal models, an effect that could be related to neurological sequelae of prolonged or excessive anesthesia in man. It has been proposed that toxicity of anesthetic agents could be caused by inhibition of the electron transport system. In this study, using high-resolved respirometry of human blood cells, the objective was to evaluate the influence of commonly used anesthetic agents in a wide concentration range on mitochondrial oxygen consumption in platelets.''Materials and Methods'': Platelets samples were isolated from healthy volunteers and were rapidly analyzed by [[high-resolution respirometry]] using an Oroboros-2k Oxygraph. Platelets were exposed to propofol (5-150 μg/mL), sevoflurane (0.4-8 mmol/L) and midazolam (0.1-20 μg/mL). Mitochondria were stimulated with complex-specific substrates and inhibitors. Statistical analysis were performed using one way ANOVA with post hoc Dunnett’s test and were compared to a separate control group (''N''＝20). Informed consent was received from all participants and the study was approved by the ethical committee of Tokyo Medical University.''Results and Discussion'': Within the therapeutic concentration-range of the investigated agents, no apparent inhibition of respiratory capacity was noted. Rather, at therapeutic concentrations, significant increases in mitochondrial respiratory parameters were detected for sevoflurane and propofol. Dose-dependent inhibition of respiration was found in the presence of high doses of propofol (30 μg/mL and above) and sevoflurane (1.6 mmol/L and above). The respiratory inhibition was more prominent for Complex I respiration as compared to Complex II-supported respiration. For midazolam no significant effects were noted at the concentration range investigated.''Conclusion'': In freshly isolated and permeabilized human platelets, the commonly used anesthetics sevoflurane and propofol stimulate mitochondrial respiratory capacity at clinically relevant concentrations. At higher concentrations, these agents displayed a dose-dependent inhibition of Complex I and II-supported respiration. The increased respiratory capacity induced by sevoflurane and propofol might be beneficial and the inhibition of respiration could be relevant to situations of prolonged or excessive exposure, especially in situations of tissue accumulation of these anesthetics. tissue accumulation of these anesthetics.)
Goncalves 2009 PLoS One + (''Background'': Hematophagy poses a challe … ''Background'': Hematophagy poses a challenge to blood-feeding organisms since products of blood digestion can exert cellular deleterious effects. Mitochondria perform multiple roles in cell biology acting as the site of aerobic energytransducing pathways, and also an important source of reactive oxygen species (ROS), modulating redox metabolism. Therefore, regulation of mitochondrial function should be relevant for hematophagous arthropods. Here, we investigated the effects of blood-feeding on flight muscle (FM) mitochondria from the mosquito ''Aedes aegypti'', a vector of dengue and yellow fever.''Methodology/Principal Findings'': Blood-feeding caused a reversible reduction in mitochondrial oxygen consumption, anevent that was parallel to blood digestion. These changes were most intense at 24 h after blood meal (ABM), the peak ofblood digestion, when oxygen consumption was inhibited by 68%. Cytochromes ''c'' and ''a+a3 '' levels and cytochrome c oxidase activity of the electron transport chain were all reduced at 24 h ABM. Ultrastructural and molecular analyses of FM revealed that mitochondria fuse upon blood meal, a condition related to reduced ROS generation. Consistently, BF induced a reversible decrease in mitochondrial H2O2 formation during blood digestion, reaching their lowest values at 24 h ABM where a reduction of 51% was observed.''Conclusion'': Blood-feeding triggers functional and structural changes in hematophagous insect mitochondria, which mayrepresent an important adaptation to blood feeding.ct mitochondria, which may represent an important adaptation to blood feeding.)
Favory 2006 Am J Respir Crit Care Med + (''Background'': Results from both animal a … ''Background'': Results from both animal and human being studies provide evidence that inhalation of concentrations of carbon monoxide (CO) at around 100 ppm has antiinflammatory effects. These low levels of CO are incriminated in ischemic heart diseases experienced by cigarette smokers and, in some cases, from air pollution. Although neurologic mechanisms have been investigated, the effects of CO on cardiovascular function are still poorly understood.''Methods and Results'': The effects of CO (250 ppm; 90 min) inhalation on myocardial function were investigated in isolated heart of rats killed immediately, and 3, 24, 48, and 96 h after CO exposure. CO exposure at 250 ppm resulted in an arterial carboxyhemoglobin (HbCO) level of approximately 11%, which was not associated with changes in mean arterial pressure and heart rate. CO exposure induced coronary perfusion pressure increases, which were associated with endothelium-dependent and -independent vascular relaxation abnormalities. CO-induced coronary vascular relaxation perturbations were observed in the presence of increased heart contractility. Spontaneous peak to maximal Ca2+-activated left ventricular pressure ratio was markedly increased in CO-exposed rats, indicating increases in myofilament calcium sensitivity. Heart cyclic guanosine monophosphate/cAMP ratio and myocardial permeabilized fiber respiration (complex intravenous activity) were reduced in CO-exposed rats, which lasted after 48 h of reoxygenation in air.''Conclusions'': These findings suggest that CO deteriorates heart oxygen supply to utilization and potentially may induce myocardial hypoxia through mechanisms that include increased oxygen demand due to increased contractility, reduced coronary blood flow reserve, and cardiomyocyte respiration inhibition.low reserve, and cardiomyocyte respiration inhibition.)
Votion 2012 PLoS One + (''Background'': Within the animal kingdom, … ''Background'': Within the animal kingdom, horses are among the most powerful aerobic athletic mammals. Determination of muscle respiratory capacity and control improves our knowledge of mitochondrial physiology in horses and high aerobic performance in general.We applied high-resolution respirometry and multiple [[substrate-uncoupler-inhibitor titration]] protocols to study mitochondrial physiology in small (1.0 – 2.5 mg) permeabilized muscle fibres sampled from triceps brachii of healthy horses. Oxidative phosphorylation ([[OXPHOS]]) capacity [pmol O2∙s-1∙mg-1 wet weight] in the NADH&succinate-pathway (NS, combined [[CI&II]]-linked substrate supply: glutamate&malate&succinate) increased from 77±18 in overweight horses to 103±18, 122±15, and 129±12 in untrained, trained andcompetitive horses (''N'' = 3, 8, 16, and 5, respectively). Similar to human muscle mitochondria, equine OXPHOS capacity was limited by the phosphorylation system to 0.85±0.10 (''N'' = 32) of electron transfer capacity, independent of fitness level. In 15 trained horses, OXPHOS capacity increased from 119±12 to 134±37 when pyruvate was included in the NS-substrate cocktail. Relative to this maximum OXPHOS capacity, NADH-linked OXPHOS capacities (N) were only 50 % with glutamate&malate, 64 % with pyruvate&malate, and 68 % with pyruvate&glutamate&malate, and ~78 % with succinate&rotenone (S). OXPHOS capacity with glutamate&malate increased with fitness relative to NS-supported ET capacity from a flux control ratio of 0.38 to 0.40, 0.41 and 0.46 in overweight to competitive horses, whereas the S/NS substrate control ratio remained constant at 0.70. Therefore, the apparent deficit of the N- over S-pathway capacity was reduced with physical fitness. The scope of mitochondrial density-dependent OXPHOS capacity and the density-independent (qualitative) increase of N-respiratory capacity with increased fitness open up new perspectives of integrative and comparative mitochondrial respiratory physiology.tory capacity with increased fitness open up new perspectives of integrative and comparative mitochondrial respiratory physiology.)
Luevano-Martinez 2019 Fungal Biol + (''Blastocladiella emersonii'' is an early … ''Blastocladiella emersonii'' is an early diverging fungus of the phylum Blastocladiomycota. During the life cycle of the fungus, mitochondrial morphology changes significantly, from a fragmented form in sessile vegetative cells to a fused network in motile zoospores. In this study, we visualize these morphological changes using a mitochondrial fluorescent probe and show that the respiratory capacity in zoospores is much higher than in vegetative cells, suggesting that mitochondrial morphology could be related to the differences in oxygen consumption. While studying the respiratory chain of the fungus, we observed an antimycin A and cyanide-insensitive, salicylhydroxamic (SHAM)-sensitive respiratory activity, indicative of a mitochondrial alternative oxidase (AOX) activity. The presence of AOX was confirmed by the finding of a ''B. emersonii'' cDNA encoding a putative AOX, and by detection of AOX protein in immunoblots. Inhibition of AOX activity by SHAM was found to significantly alter the capacity of the fungus to grow and sporulate, indicating that AOX participates in life cycle control in ''B. emersonii''.Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.ed by Elsevier Ltd. All rights reserved.)
Thorgersen 2022 Front Microbiol + (''Brevibacillus massiliensis'' strain phR … ''Brevibacillus massiliensis'' strain phR is an obligately aerobic microbe that was isolated from human feces. Here, we show that it readily takes up tungsten (W), a metal previously associated only with anaerobes. The W is incorporated into an oxidoreductase enzyme (BmWOR) that was purified from native biomass. BmWOR consists of a single 65 kDa subunit and contains a single W-pyranopterin cofactor and a single [4Fe-4S] cluster. It exhibited high aldehyde-oxidizing activity with very high affinities (apparent ''K''m < 6 μM) for aldehydes common in the human gut and in cooked foods, including furfural, propionaldehyde, benzaldehyde and tolualdehyde, suggesting that BmWOR plays a key role in their detoxification. ''B. massiliensis'' converted added furfural to furoic acid when grown in the presence of W, but not in the presence of the analogous element molybdenum. ''B. massiliensis'' ferredoxin (BmFd) served as the electron acceptor (apparent ''K''m < 5 μM) for BmWOR suggesting it is the physiological electron carrier. Genome analysis revealed a Fd-dependent rather than NADH-dependent Complex I, suggesting that WOR not only serves a detoxification role but its aldehyde substrates could also serve as a source of energy. BmWOR is the first tungstoenzyme and the first member of the WOR family to be obtained from a strictly aerobic microorganism. Remarkably, BmWOR oxidized furfural in the presence of air (21 % O2, v/v) but only if BmFd was also present. BmWOR is the first characterized member of the Clade 83 WORs, which are predominantly found in extremely halophilic and aerobic archaea (Clade 83A), with many isolated from food sources, while the remaining bacterial members (Clade 83B) include both aerobes and anaerobes. The potential advantages for microbes found in foods and involved in human gut health that harbor O2-resistant WORs, including in ''Bacillus'' and ''Brevibacillus'' based-probiotics, are discussed.Brevibacillus'' based-probiotics, are discussed.)
Wyss 2016 Abstract IOC116 + (''By author request, this abstract is not made available online.'')
Piller 1995 J Exp Biol + (''Callinectes sapidus'' and ''C. similis'' … ''Callinectes sapidus'' and ''C. similis'' co-occur in estuarine waters above 15 salinity. ''Callinectes sapidus'' also inhabits more dilute waters, but ''C. similis'' is rarely found below 15 . Previous work suggests that ''C. sapidus'' may be a better hyperosmoregulator than ''C. similis''. In this study, energy metabolism and the levels of transport-related enzymes in excised gills were used as indicators of adaptation to low salinity. Oxygen consumption rates and mitochondrial cytochrome content of excised gills increased in both species as acclimation salinity decreased, but to a significantly greater extent in ''C. similis'' gills. In addition, ''C. similis'' gills showed the same levels of carbonic anhydrase and Na+/K+-ATPase activities and the same degree of enzyme induction during low-salinity adaptation as has been reported for ''C. sapidus'' gills. However, hemolymph osmolality and ion concentrations were consistently lower in ''C. similis'' at low salinity than in ''C. sapidus''. Therefore, although gills from low-salinity-acclimated ''C. similis'' have a higher oxygen consumption rate and more mitochondrial cytochromes than ''C. sapidus'' gills and the same level of transport-related enzymes, ''C. similis'' cannot homeostatically regulate their hemolymph to the same extent as ''C. sapidus.''ymph to the same extent as ''C. sapidus.'')
Dufour 2013 Appl Environ Microbiol + (''Campylobacter jejuni'' is a widespread p … ''Campylobacter jejuni'' is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. The use of natural antimicrobial molecules is a promising alternative to antibiotic treatments for pathogen control in the food industry. Isothiocyanates are natural antimicrobial compounds, which also display anti-cancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood.We investigated the early cellular response of ''C. jejuni'' to benzylisothiocyanate by both transcriptomic and physiological approaches. The transcriptomic response of ''C. jejuni'' to benzylisothiocyanate showed upregulation of heat shock response genes and an impact on energy metabolism. The oxygen consumption was progressively impaired by benzylisothiocyanate treatment as revealed by high-resolution respirometry, while the ATP content increased soon after benzylisothiocyanate exposition, which suggests a shift in the energy metabolism balance. Finally, benzylisothiocyanate induced intracellular protein aggregation. These results indicate that benzylisothiocyanate affects ''C. jejuni'' by targeting proteins, resulting in the disruption of major metabolic processes and eventually leading to cell death.sses and eventually leading to cell death.)
Roach 2013 Bioch Biophys Acta - Bioenergetics + (''Chlamydomonas reinhardtii'' is a photoau … ''Chlamydomonas reinhardtii'' is a photoautotrophic green alga, which can be grown mixotrophically in acetate-supplemented media (Tris-acetate-phosphate). We show that acetate has a direct effect on photosystem II (PSII). As a consequence, Tris-acetate-phosphate-grown mixotrophic C. reinhardtii cultures are less susceptible to photoinhibition than photoautotrophic cultures when subjected to high light. Spin-trapping electron paramagnetic resonance spectroscopy showed that thylakoids from mixotrophic C. reinhardtii produced less (1)O2 than those from photoautotrophic cultures. The same was observed in vivo by measuring DanePy oxalate fluorescence quenching. Photoinhibition can be induced by the production of (1)O2 originating from charge recombination events in photosystem II, which are governed by the midpoint potentials (Em) of the quinone electron acceptors. Thermoluminescence indicated that the Em of the primary quinone acceptor (QA/QA(-)) of mixotrophic cells was stabilised while the Em of the secondary quinone acceptor (QB/QB(-)) was destabilised, therefore favouring direct non-radiative charge recombination events that do not lead to (1)O2 production. Acetate treatment of photosystem II-enriched membrane fragments from spinach led to the same thermoluminescence shifts as observed in C. reinhardtii, showing that acetate exhibits a direct effect on photosystem II independent from the metabolic state of a cell. A change in the environment of the non-heme iron of acetate-treated photosystem II particles was detected by low temperature electron paramagnetic resonance spectroscopy. We hypothesise that acetate replaces the bicarbonate associated to the non-heme iron and changes the environment of QA and QB affecting photosystem II charge recombination events and photoinhibition. recombination events and photoinhibition.)
De Carvalho 2016 J Cell Biochem + (''Diabetes mellitus'' is a metabolic disor … ''Diabetes mellitus'' is a metabolic disorder characterized by hyperglycemia. We investigated the effect of a prior 30 days voluntary exercise protocol on STZ-diabetic CF1 mice. Glycemia, and the liver and skeletal muscle glycogen, mitochondrial function, and redox status were analyzed up to 5 days after STZ injection. Animals were engaged in the following groups: Sedentary vehicle (Sed Veh), Sedentary STZ (Sed STZ), Exercise Vehicle (Ex Veh), and Exercise STZ (Ex STZ). Exercise prevented fasting hyperglycemia in the Ex STZ group. In the liver, there was decreased on glycogen level in Sed STZ group but not in EX STZ group. STZ groups showed decreased mitochondrial oxygen consumption compared to vehicle groups, whereas mitochondrial H2O2 production was not different between groups. Addition of ADP to the medium did not decrease H2O2 production in Sed STZ mice. Exercise increased GSH level. Sed STZ group increased nitrite levels compared to other groups. In quadriceps muscle, glycogen level was similar between groups. The Sed STZ group displayed decreased O2 consumption, and exercise prevented this reduction. The H2O2 production was higher in Ex STZ when compared to other groups. Also, GSH level decreased whereas nitrite levels increased in the Sed STZ compared to other groups. The PGC1 α levels increased in Sed STZ, Ex Veh, and Ex STZ groups. In summary, prior exercise training prevents hyperglycemia in STZ-mice diabetic associated with increased liver glycogen storage, and oxygen consumption by the mitochondria of skeletal muscle implying in increased oxidative/biogenesis capacity, and improved redox status of both tissues. J. Cell. Biochem. 9999: 1-8, 2016. © 2016 Wiley Periodicals, Inc.© 2016 Wiley Periodicals, Inc.edox status of both tissues. J. Cell. Biochem. 9999: 1-8, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.)
Scialo 2016 PLOS ONE + (''Drosophila melanogaster'' is a popular r … ''Drosophila melanogaster'' is a popular research model organism thanks to its powerful genetic tools that allow spatial and temporal control of gene expression. The inducible GeneSwitch Gal4 system (GS) system is a modified version of the classic UAS/GAL4 system which allows inducible regulation of gene expression and eliminates background effects. It is widely acknowledged that the GS system is leaky, with low level expression of UAS transgenes in absence of the inducer RU-486 (the progesterone analog that activates the modified GAL4 protein). However, in the course of our experiments, we have observed that the extent of this leak depends on the nature of the transgene being expressed. In the absence of RU-486, when strong drivers are used to express protein coding transgenes, leaky expression is low or negligible, however expression of RNA interference (RNAi) transgenes results in complete depletion of protein levels. The majority of published studies, using the GS system and RNAi transgenes validate knock-down efficiency by comparing target gene mRNA levels between induced and non-induced groups. Here, we demonstrate that this approach is lacking and that both additional control groups and further validation is required at the protein level. Unfortunately, this experimental limitation of the GS system eliminates "the background advantage", but does offer the possibility of performing more complex experiments (e.g. studying depletion and overexpression of different proteins in the same genetic background). The limitations and new possible applications of the GS system are discussed in detail. of the GS system are discussed in detail.)
Oliveira 2023 MitoFit Spotlight + (''Drosophila'' fruit flies have been used … ''Drosophila'' fruit flies have been used as a valuable, cheap, and powerful organism model to understand fundamental biological processes for many years. However, standardized methodologies specifically designed to assess mitochondrial physiology in this model are not available. Rodríguez and colleagues provided a detailed analysis of publicly available protocols to assess mitochondrial physiology in ''Drosophila melanogaster'' while performed experiments in flight muscles to address three technical parameters to define the optimal conditions for respirometry. The authors show that oxygen diffusion is not limited to sustaining respiratory capacity in either isolated mitochondria or chemically permeabilized fibers. In addition, chemical permeabilization revealed the best approach to assess mitochondrial physiology in fruit flies. Finally, the authors demonstrate that magnesium green is the only fluorescent probe that caused no effects on respiratory rates. Methodological standardization to study ''Drosophila'' mitochondrial physiology, as presented by Rodríguez and colleagues, represents a critical step towards more reproducible and comparative metabolic research in this important organism model. arch in this important organism model. )
Oliveira 2023 MitoFit + (''Drosophila'' melanogaster is undoubtedly … ''Drosophila'' melanogaster is undoubtedly one of the most useful model organisms in biology. From a bioenergectics and metabolism point-of-view, its four discrete life cycle stages, each with particular nutritional and energetic demands, represent multiple powerful experimental systems in a single organism. Extensive resources are available for the community of ''Drosophila'' researchers worldwide, including an ever-growing number of mutant, transgenic and genomically-edited lines currently being developed and carried by stock centers in North America, Europe and Asia. Here, we provide evidence for the importance of stock centers in sustaining the substantial increase in the output of ''Drosophila'' mitochondrial research worldwide in recent decades. We also argue that the difficulties in transporting fly lines into South America has stalled the progression of related ''Drosophila'' research areas in the continent. Establishing a local stock center is the first step towards building a strong local ''Drosophila'' community that will contribute to the general field of mitochondrial research. neral field of mitochondrial research. )
De Carvalho 2017 Toxicol Research + (''Eugenia uniflora'' L(Myrtaceae family) h … ''Eugenia uniflora'' L(Myrtaceae family) has demonstrated several properties of human interest, including insecticide potential, due to its pro-oxidant properties. These properties likely result from the effects on its mitochondria, but the mechanism of this action is unclear. The aim of this work was to evaluate the mitochondrial bioenergetics function in ''Drosophila melanogaster'' exposed to ''E. uniflora'' leaf essential oil. For this, we used a high-resolution respirometry (HRR) protocol. We found that ''E. uniflora'' promoted a collapse of the mitochondrial transmembrane potential (ΔΨm). In addition the essential oil was able to promote the disruption of respiration coupled to oxidative phosphorylation (OXPHOS) and inhibit the respiratory electron transfer-pathway (ET-pathway) established with an uncoupler. In addition, exposure led to decreases of respiratory control ratio (RCR), bioenergetics capacity and OXPHOS coupling efficiency, and induced changes in the substrate control ratio. Altogether, our results suggested that ''E. uniflora'' impairs the mitochondrial function/viability and promotes the uncoupling of OXPHOS, which appears to play an important role in the cellular bioenergetics failure induced by essential oil in ''D. melanogaster''.d by essential oil in ''D. melanogaster''.)
Schatz 2011 Feuersucher + (''From'' [http://www.annualreviews.org/doi … ''From'' [http://www.annualreviews.org/doi/pdf/10.1146/annurev-biochem-081009-125448 Schatz G (2012) The fires of life. Annu Rev Biochem 81: 34–59.]:This retrospective recounts the hunt for the mechanism of mitochondrialATP synthesis, the early days of research on mitochondrial formation,and some of the colorful personalities dominating these oftendramatic and emotional efforts. The narrative is set against the backdropof postwar Austria and Germany and the stream of young scientistswho had to leave their countries to receive postdoctoral trainingabroad. Many of them—including the author—chose the laboratory ofa scientist their country had expelled a few decades before. The articleconcludes with some thoughts on the uniqueness of U.S. research universitiesand a brief account of the struggles to revive science in Europe.Illustriert von P. Leslie Dutton Europe. Illustriert von P. Leslie Dutton)
Gordillo 2015 Can J Microbiol + (''Geotrichum citri-aurantii'' is a posthar … ''Geotrichum citri-aurantii'' is a postharvest phytopathogenic fungus of lemons. We studied the mode of action of antifungal metabolites from ''Bacillus sp.'' strain IBA 33 on arthroconidia of ''G. citri-aurantii''. These metabolites are lipopeptides belonging to the iturin family. Membrane permeabilization of ''G. citri-aurantii'' was analyzed and mitochondrial respiratory rate was evaluated. Disturbance of the plasma membrane promotes the leakage of many cellular components into the surrounding media, and mitochondrial membrane disorganization promotes the inhibition of the respiratory rate. Our findings provide insights into the ability of lipopeptides to suppress plant fungal pathogens and their possible agronomical applications.d their possible agronomical applications.)
Mastronicola 2011 IUBMB Life + (''Giardia intestinalis'' is the microaerop … ''Giardia intestinalis'' is the microaerophilic protozoon causing giardiasis, a common infectious intestinal disease. ''Giardia'' possesses an O2 -scavenging activity likely essential for survival in the host. We report that Giardia trophozoites express the O2 -detoxifying flavodiiron protein (FDP), detected by immunoblotting, and are able to reduce O2 to H2O rapidly (∼3 μM O2 × min × 106 cells at 37 °C) and with high affinity (C50 = 3.4 ± 0.7 μM O2). Following a short-term (minutes) exposure to H2O2 ≥ 100 μM, the O2 consumption by the parasites is irreversibly impaired, and the FDP undergoes a degradation, prevented by the proteasome-inhibitor MG132. Instead, H2O2 does not cause degradation or inactivation of the isolated FDP. On the basis of the elevated susceptibility of ''Giardia'' to oxidative stress, we hypothesize that the parasite preferentially colonizes the small intestine since, compared with colon, it is characterized by a greater capacity for redox buffering and a lower propensity to oxidative stress.e that the parasite preferentially colonizes the small intestine since, compared with colon, it is characterized by a greater capacity for redox buffering and a lower propensity to oxidative stress.)
Mendoza-Fuentes 2023 PeerJ + (''Heterotheca inuloides'', traditionally e … ''Heterotheca inuloides'', traditionally employed in Mexico, has demonstrated anticancer activities. Although it has been proven that the cytotoxic effect is attributed to cadinane-type sesquiterpenes such as 7-hydroxy-3,4-dihydrocadalene, the mechanism of action by which these agents act in tumor lines and their regulation remain unknown. This study was undertaken to investigate for first time the cytotoxic activity and mechanism of action of 7-hydroxy-3,4-dihydrocadalene and two semi-synthetic cadinanes derivatives towards breast cancer cells.Cell viability and proliferation were assayed by thiazolyl blue tetrazolium bromide (MTT) assay and Trypan blue dye exclusion assay. Cell migration measure was tested by wound-healing assay. Moreover, the reactive oxygen species (ROS) and lipid peroxidation generation were measured by 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay and thiobarbituric acid reactive substance (TBARS) assay, respectively. Furthermore, expression of caspase-3, Bcl-2 and GAPDH were analyzed by western blot.The results showed that 7-hydroxy-3,4-dihydrocadalene inhibited MCF7 cell viability in a concentration and time dependent manner. The cytotoxic potency of semisynthetic derivatives 7-(phenylcarbamate)-3,4-dihydrocadalene and 7-(phenylcarbamate)-cadalene was remarkably lower. Moreover, ''in silico'' studies showed that 7-hydroxy-3,4-dihydrocadalene, and not so the semi-synthetic derivatives, has optimal physical-chemical properties to lead a promising cytotoxic agent. Further examination on the action mechanism of 7-hydroxy-3,4-dihydrocadalene suggested that this natural product exerted cytotoxicity via oxidative stress as evidenced in a significantly increase of intracellular ROS levels and in an induction of lipid peroxidation. Furthermore, the compound increased caspase-3 and caspase-9 activities and slightly inhibited Bcl-2 levels. Interestingly, it also reduced mitochondrial ATP synthesis and induced mitochondrial uncoupling.Taken together, 7-hydroxy-3,4-dihydrocadalene is a promising cytotoxic compound against breast cancer via oxidative stress-induction.ast cancer via oxidative stress-induction.)
Harari 2015 Vintage + (''Homo deus'' shows us where we're going. … ''Homo deus'' shows us where we're going. Yuval Harari envisions a near future in sihch we face a new set of challenges. ''Homo deus'' exlores the projects, dreams and nightmares that will shape the twendty-first century and beyond - from overcoming death to creating artificial life. It asks the fundamental questions: how can we protect this fragile world from our own desctructive power? And what does our future hold?tive power? And what does our future hold?)
McMurray 2019 FASEB J + (''In utero'' overnutrition can predispose … ''In utero'' overnutrition can predispose offspring to metabolic disease. Although the mechanisms are unclear, increased oxidative stress accelerating cellular aging has been shown to play a role. Mitochondria are the main site of reactive oxygen species (ROS) production in most cell types. Levels of ROS and the risk for oxidative damage are dictated by the balance between ROS production and antioxidant defense mechanisms. Originally considered as toxic species, physiologic levels of ROS are now known to be essential cell signaling molecules. Using a model of maternal overnutrition in C57BL6N mice, we investigate the mechanisms involved in the development of insulin resistance (IR) in muscle. In red and white gastrocnemius muscles of offspring, we are the first to report characteristics of oxidative phosphorylation, H2O2 production, activity of mitoflashes, and electron transport chain supercomplex formation. Results demonstrate altered mitochondrial function with reduced response to glucose in offspring of mice fed a high-fat and high-sucrose diet, increases in mitochondrial leak respiration, and a reduction in ROS production in red gastrocnemius in response to palmitoyl carnitine. We also demonstrate differences in supercomplex formation between red and white gastrocnemius, which may be integral to fiber-type specialization. We conclude that in this model of maternal overnutrition, mitochondrial alterations occur before the development of IR.ion, mitochondrial alterations occur before the development of IR.)
Holt 1988 Nature + (''In vitro'' studies of muscle mitochondri … ''In vitro'' studies of muscle mitochondrial metabolism in patients with mitochondrial myopathy have identified a variety of functional defects of the mitochondrial respiratory chain, predominantly affecting complex I (NADH-CoQ reductase) or complex III (ubiquinol-cytochrome c reductase) in adult cases. These two enzymes consist of approximately 36 subunits, eight of which are encoded by mitochondrial DNA (mtDNA). The increased incidence of maternal, as opposed to paternal, transmission in familial mitochondrial myopathy suggests that these disorders may be caused by mutations of mtDNA. Multiple restriction endonuclease analysis of leukocyte mtDNA from patients with the disease, and their relatives, showed no differences in cleavage patterns between affected and unaffected individuals in any single maternal line. When muscle mtDNA was studied, nine of 25 patients were found to have two populations of muscle mtDNA, one of which had deletions of up to 7 kilobases in length. These observations demonstrate that mtDNA heteroplasmy can occur in man and that human disease may be associated with defects of the mitochondrial genome. with defects of the mitochondrial genome.)
JanssenDuijghuijsen 2017 Front Physiol + (''In vivo'' studies suggest that intestina … ''In vivo'' studies suggest that intestinal barrier integrity is dependent on mitochondrial ATP production. Here, we aim to provide mechanistic support, using an ''in vitro'' model mimicking the oxidative ''in vivo'' situation.Human Caco-2 cells were cultured for 10 days in culture flasks orfor 14 days on transwell inserts in either glucose-containing or galactose-containingmedium. Mitochondria were visualized and cellular respiration and levels of oxidativephosphorylation (OXPHOS) proteins were determined. Mitochondrial ATP depletionwas induced using CCCP, rotenone, or piericidin A (PA). Monolayer permeability wasassessed using transepithelial electrical resistance (TEER) and fluorescein flux. Geneexpression and cellular distribution of tight junction proteins were analyzed.Caco-2 cells cultured in galactose-containing, but not in glucose-containing,medium showed increased mitochondrial connectivity, oxygen consumption rates andlevels of OXPHOS proteins. Inhibition of mitochondrial ATP production using CCCP,rotenone or PA resulted in a dose-dependent increase in Caco-2 monolayer permeability.In-depth studies with PA showed a six fold decrease in cellular ATP and revealedincreased gene expression of tight junction proteins (TJP) 1 and 2, occludin, and claudin1, but decreased gene expression of claudin 2 and 7. Of these, claudin 7 was clearlyredistributed from the cellular membrane into the cytoplasm, while the others were not(TJP1, occludin) or slightly (claudin 2, actin) affected. ''In vivo'' studies suggest that intestinal barrier integrity is dependent on mitochondrial ATP production. Here, we aim to providemechanistic support, using an ''in vitro'' model mimicking the oxidative ''in vivo'' situation.Well-functioning mitochondria are essential for maintaining cellularenergy status and monolayer integrity of galactose grown Caco-2 cells. Energydepletion-induced Caco-2 monolayer permeability may be facilitated by changes in thedistribution of claudin 7. changes in the distribution of claudin 7.)
Wagner 1998 Plant Physiol + (''In vivo'' ubiquinone (UQ) reduction leve … ''In vivo'' ubiquinone (UQ) reduction levels were measured during the development of the inflorescences of ''Arum maculatum'' and ''Amorphophallus krausei''. Thermogenesis in ''A. maculatum'' spadices appeared not to be confined to a single developmental stage, but occurred during various stages. The UQ pool in both ''A. maculatum'' and ''A. krausei'' appendices was approximately 90% reduced during thermogenesis. Respiratory characteristics of isolated appendix mitochondria did not change in the period around thermogenesis. Apparently, synthesis of the required enzyme capacity is regulated via a coarse control upon which a fine control of metabolism that regulates the onset of thermogenesis is imposed.tes the onset of thermogenesis is imposed.)
Rocco-Machado 2019 Free Radic Biol Med + (''Leishmania amazonensis'' is one of leish … ''Leishmania amazonensis'' is one of leishmaniasis' causative agents, a disease that has no cure and leads to the appearance of cutaneous lesions. Recently, our group showed that heme activates a Na+/K+ ATPase in these parasites through a signaling cascade involving hydrogen peroxide (H2O2) generation. Heme has a pro-oxidant activity and signaling capacity, but the mechanism by which this molecule increases H2O2 levels in ''L. amazonensis'' has not been elucidated. Here we investigated the source of H2O2 stimulated by heme, ruling out the participation of mitochondria and raising the possibility of a role for a NADPH oxidase (Nox) activity. Despite the absence of a classical Nox sequence in trypanosomatid genomes, ''L. amazonensis'' expresses a surface ferric iron reductase (LFR1). Interestingly, Nox enzymes are thought to have evolved from ferric iron reductases because they share same core domain and are very similar in structure. The main difference is that Nox catalyses electron flow from NADPH to oxygen, generating reactive oxygen species (ROS), while ferric iron reductase promotes electron flow to ferric iron, generating ferrous iron. Using ''L. amazonensis'' overexpressing or knockout for LFR1 and heterologous expression of LFR1 in mammalian embryonic kidney (HEK 293) cells, we show that this enzyme is bifunctional, being able to generate both ferrous iron and H2O2. It was previously described that protozoans knockout for LFR1 have their differentiation to virulent forms (amastigote and metacyclic promastigote) impaired. In this work, we observed that LFR1 overexpression stimulates protozoan differentiation to amastigote forms, reinforcing the importance of this enzyme in ''L. amazonensis'' life cycle regulation. Thus, we not only identified a new source of ROS production in Leishmania, but also described, for the first time, an enzyme with both ferric iron reductase and Nox activities.Copyright © 2019 Elsevier Inc. All rights reserved.o described, for the first time, an enzyme with both ferric iron reductase and Nox activities. Copyright © 2019 Elsevier Inc. All rights reserved.)
Pinho 2020 PLoS Negl Trop Dis + (''Leishmania'' species are responsible for … ''Leishmania'' species are responsible for a broad spectrum of diseases, denominated Leishmaniasis, affecting over 12 million people worldwide. During the last decade, there have been impressive efforts for sequencing the genome of most of the pathogenic ''Leishmania'' spp. as well as hundreds of strains, but large-scale proteomics analyses did not follow these achievements and the ''Leishmania'' proteome remained mostly uncharacterized. Here, we report a comprehensive comparative study of the proteomes of strains representing ''L. braziliensis'', ''L. panamensis'' and ''L. guyanensis'' species. Proteins extracted by SDS-mediated lysis were processed following the multi-enzyme digestion-filter aided sample preparation (FASP) procedure and analysed by high accuracy mass spectrometry. "Total Protein Approach" and "Proteomic Ruler" were applied for absolute quantification of proteins. Principal component analysis demonstrated very high reproducibility among biological replicates and a very clear differentiation of the three species. Our dataset comprises near 7000 proteins, representing the most complete ''Leishmania'' proteome yet known, and provides a comprehensive quantitative picture of the proteomes of the three species in terms of protein concentration and copy numbers. Analysis of the abundance of proteins from the major energy metabolic processes allow us to highlight remarkably differences among the species and suggest that these parasites depend on distinct energy substrates to obtain ATP. Whereas ''L. braziliensis'' relies the more on glycolysis, ''L. panamensis'' and ''L. guyanensis'' seem to depend mainly on mitochondrial respiration. These results were confirmed by biochemical assays showing opposite profiles for glucose uptake and O2 consumption in these species. In addition, we provide quantitative data about different membrane proteins, transporters, and lipids, all of which contribute for significant species-specific differences and provide rich substrate for explore new molecules for diagnosing purposes. Data are available via ProteomeXchange with identifier PXD017696.ailable via ProteomeXchange with identifier PXD017696.)
MitoCom2014 + (''MitoCom'' closing event and perspectives. Innsbruck, Austria; 2014 October 16)
Barsottini 2020 Commun Biol + (''Moniliophthora perniciosa'' is a fungal … ''Moniliophthora perniciosa'' is a fungal pathogen and causal agent of the witches' broom disease of cocoa, a threat to the chocolate industry and to the economic and social security in cocoa-planting countries. The membrane-bound enzyme alternative oxidase (MpAOX) is crucial for pathogen survival; however a lack of information on the biochemical properties of MpAOX hinders the development of novel fungicides. In this study, we purified and characterised recombinant MpAOX in dose-response assays with activators and inhibitors, followed by a kinetic characterization both in an aqueous environment and in physiologically-relevant proteoliposomes. We present structure-activity relationships of AOX inhibitors such as colletochlorin B and analogues which, aided by an MpAOX structural model, indicates key residues for protein-inhibitor interaction. We also discuss the importance of the correct hydrophobic environment for MpAOX enzymatic activity. We envisage that such results will guide the future development of AOX-targeting antifungal agents against ''M. perniciosa'', an important outcome for the chocolate industry.ortant outcome for the chocolate industry.)
Yurre 2020 Arq Bras Cardiol + (''Moringa oleifera'' seeds, which are used … ''Moringa oleifera'' seeds, which are used for water clarification, contain a lectin named WSMoL which has shown ''in vitro'' antibacterial and immunomodulatory activity. Due to their nutritional value and therapeutic potential, the leaves and seeds of this tree are eaten in some communities. Some plant lectins are non-toxic to mammals, but others have been reported to be harmful when ingested or administered by other means. As one of the steps needed to define the safety of WSMoL, we evaluated possible cardiotoxic effects of this purified protein. WSMoL was administered for 21 consecutive days to mice by gavage. Electrophysiological, mechanical, and metabolic cardiac functions were investigated by ''in vivo'' and ''ex vivo'' electrocardiographic recordings, nuclear magnetic resonance, and high-resolution respirometry. The treatment with WSMoL did not induce changes in blood glucose levels or body weight in comparison with control group. Moreover, the heart weight/body weight and heart weight/tibia length ratios were similar in both groups. Lectin ingestion also did not modify glucose tolerance or insulin resistance. No alterations were observed in electrocardiographic parameters or cardiac action potential duration. The heart of mice from the control and WSMoL groups showed preserved left ventricular function. Furthermore, WSMoL did not induce changes in mitochondrial function (in all cases, p > 0.05). The administration of WSMoL demonstrated a cardiac safety profile. These results contribute to the safety evaluation of using ''M. oleifera'' seeds to treat water, since this lectin is present in the preparation employed by some populations to this end.ion employed by some populations to this end.)
Pelaez Coyotl 2020 Pharmaceutics + (''Mycobacterium tuberculosis'' (MTB) is th … ''Mycobacterium tuberculosis'' (MTB) is the principal cause of human tuberculosis (TB), which is a serious health problem worldwide. The development of innovative therapeutic modalities to treat TB is mainly due to the emergence of multi drug resistant (MDR) TB. Autophagy is a cell-host defense process. Previous studies have reported that autophagy-activating agents eliminate intracellular MDR MTB. Thus, combining a direct antibiotic activity against circulating bacteria with autophagy activation to eliminate bacteria residing inside cells could treat MDR TB. We show that the synthetic peptide, IP-1 (KFLNRFWHWLQLKPGQPMY), induced autophagy in HEK293T cells and macrophages at a low dose (10 μM), while increasing the dose (50 μM) induced cell death; IP-1 induced the secretion of TNFα in macrophages and killed Mtb at a dose where macrophages are not killed by IP-1. Moreover, IP-1 showed significant therapeutic activity in a mice model of progressive pulmonary TB. In terms of the mechanism of action, IP-1 sequesters ATP ''in vitro'' and inside living cells. Thus, IP-1 is the first antimicrobial peptide that eliminates MDR MTB infection by combining four activities: reducing ATP levels, bactericidal activity, autophagy activation, and TNFα secretion. autophagy activation, and TNFα secretion.)
Iqbal 2018 Pathogens + (''Mycobacterium tuberculosis'' (Mtb) exhib … ''Mycobacterium tuberculosis'' (Mtb) exhibits remarkable metabolic flexibility that enables it to survive a plethora of host environments during its life cycle. With the advent of bedaquiline for treatment of multidrug-resistant tuberculosis, oxidative phosphorylation has been validated as an important target and a vulnerable component of mycobacterial metabolism. Exploiting the dependence of Mtb on oxidative phosphorylation for energy production, several components of this pathway have been targeted for the development of new antimycobacterial agents. This includes targeting NADH dehydrogenase by phenothiazine derivatives, menaquinone biosynthesis by DG70 and other compounds, terminal oxidase by imidazopyridine amides and ATP synthase by diarylquinolines. Importantly, oxidative phosphorylation also plays a critical role in the survival of persisters. Thus, inhibitors of oxidative phosphorylation can synergize with frontline TB drugs to shorten the course of treatment. In this review, we discuss the oxidative phosphorylation pathway and development of its inhibitors in detail.d development of its inhibitors in detail.)
Franco 2020 bioRxiv + (''Mycobacterium tuberculosis'' (Mtb) regul … ''Mycobacterium tuberculosis'' (Mtb) regulates the macrophage metabolic state to thrive in the host. Yet, the responsible mechanisms remain elusive. Macrophage activation towards the microbicidal (M1) program depends on the HIF-1 α-mediated metabolic shift from oxidative phosphorylation towards glycolysis. Here, we asked whether a tuberculosis (TB) microenvironment changes the M1 macrophage metabolic state. We exposed M1 macrophages to the acellular fraction of tuberculous pleural effusions (TB-PE), and found lower glycolytic activity, accompanied by elevated levels of oxidative phosphorylation and bacillary load, compared to controls. The host-derived lipid fraction of TB-PE drove these metabolic alterations. HIF-1α stabilization reverted the effect of TB-PE by restoring M1 metabolism. As a proof-of-concept, Mtb-infected mice with stabilized HIF-1α displayed lower bacillary loads and a pronounced M1-like metabolic profile in alveolar macrophages. Collectively, we demonstrate that host-derived lipids from a TB-associated microenvironment alter the M1 macrophage metabolic reprogramming by hampering HIF-1α functions, thereby impairing control of Mtb infection.hereby impairing control of Mtb infection.)
Baines 2020 Biochim Biophys Acta Bioenerg + (''No abstract available'')
Coen 2013 Obesity (Silver Spring) + (''OBJECTIVE'': The link between a reduced … ''OBJECTIVE'': The link between a reduced capacity for skeletal muscle mitochondrial fatty acid oxidation (FAO) and lipotoxicity in human insulin resistance has been the subject of intense debate. The objective of this study was to investigate whether reduced FAO is associated with elevated acyl CoA, ceramide, and diacylglycerol (DAG) in severely obese insulin resistant subjects.''DESIGN AND METHODS'': Muscle biopsies were conducted in lean (L, 22.6 ± 0.5 kg/m2, ''n'' = 8), Class I (CI, 32.1 ± 0.4 kg/m2, ''n'' = 7) and Class II&III obese (CII&III, 45.6 ± 1.1 kg/m2, ''n'' = 15) women for acyl CoA, sphingolipid and DAG profiling. Intramyocellular triglyceride (IMTG) content was determined by histology. FAO was assessed by incubating muscle homogenates with [1-C]palmitate and measuring CO2 production. Cardiolipin content was quantified as an index of mitochondrial content. Lipid metabolism proteins, DGAT1, PLIN5, and PNPLA2 were quantified in biopsy samples by western blot.''RESULTS'': CII&III were more insulin resistant (HOMA-IR: 4.5 ± 0.5 vs. 1.1 ± 0.1, ''P'' < 0.001), and had lower FAO (∼58%, ''P'' = 0.007) and cardiolipin content (∼31%, ''P'' = 0.013) compared to L. IMTG was elevated in CI (''P'' = 0.04) and CII&III (''P'' = 0.04) compared to L. Sphingolipid content was higher in CII&III compared to L (13.6 ± 1.1 vs. 10.3 ± 0.5 pmol/mg, ''P'' = 0.031) whereas DAG content was not different among groups. DGAT1 was elevated in CII&III, and PLIN5 was elevated in CI compared to L.''CONCLUSION'': Severe obesity is associated with reduced muscle oxidative capacity and occurs concomitantly with elevated IMTG, ceramide and insulin resistance.rs concomitantly with elevated IMTG, ceramide and insulin resistance.)
Ceusters 2012 Am J Vet Res + (''Objective'' To culture equine myoblasts … ''Objective'' To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the effects of horseradish peroxidase (HRP) and myeloperoxidase (MPO) on ROS production.''Animals'' 5 healthy horses (5 to 15 years old).''Procedures'' Equine skeletal myoblast cultures were derived from 1 or 2 microbiopsy specimens obtained from a triceps brachii muscle of each horse. Cultured myoblasts were exposed to conditions of anoxia followed by reoxygenation or to conditions of normoxia (control cells). Cell production of ROS in the presence or absence of HRP or MPO was assessed by use of a gas chromatography method, after which cells were treated with a 3,3′-diaminobenzidine chromogen solution to detect peroxidase binding.''Results'' Equine skeletal myoblasts were successfully cultured from microbiopsy specimens. In response to anoxia and reoxygenation, ROS production of myoblasts increased by 71%, compared with that of control cells. When experiments were performed in the presence of HRP or MPO, ROS production in myoblasts exposed to anoxia and reoxygenation was increased by 228% and 183%, respectively, compared with findings for control cells. Chromogen reaction revealed a close adherence of peroxidases to cells, even after several washes.''Conclusions and Clinical Relevance'' Results indicated that equine skeletal myoblast cultures can be generated from muscle microbiopsy specimens. Anoxia-reoxygenationtreated myoblasts produced ROS, and production was enhanced in the presence of peroxidases. This experimental model could be used to study the damaging effect of exercise on muscles in athletic horses.of exercise on muscles in athletic horses.)
Fecker 2020 Biomolecules + (''Oenothera biennis'' L. (OB), also common … ''Oenothera biennis'' L. (OB), also commonly known as evening primrose, belongs to the Onagraceae family and has the best studied biological activity of all the members in the family. In therapy, the most frequently used type of extracts are from the aerial part, which are the fatty oils obtained from the seeds and have a wide range of medicinal properties. The aim of this study was to evaluate the phytochemical composition and biological activity of OB hydroalcoholic extract and to provide directions for the antimicrobial effect, antiproliferative and pro-apoptotic potential against A375 melanoma cell line, and anti-angiogenic and anti-inflammatory capacity. The main polyphenols and flavonoids identified were gallic acid, caffeic acid, epicatechin, coumaric acid, ferulic acid, rutin and rosmarinic acid. The total phenolic content was 631.496 µgGAE/mL of extract and the antioxidant activity was 7258.67 μmolTrolox/g of extract. The tested extract had a mild bacteriostatic effect on the tested bacterial strains. It was bactericidal only against ''Candida spp.'' and ''S. aureus''. In the set of experimental conditions, the OB extract only manifested significant antiproliferative and pro-apoptotic activity against the A375 human melanoma cell line at the highest tested concentration, namely 60 μg/mL. The migration potential of A375 cells was hampered by the OB extract in a concentration-dependent manner. Furthermore, at the highest tested concentration, the OB extract altered the mitochondrial function ''in vitro'', while reducing the angiogenic reaction, hindering compact tumor formation in the chorioallantoic membrane assay. Moreover, the OB extract elicited an anti-inflammatory effect on the experimental animal model of ear inflammation.rimental animal model of ear inflammation.)
Verma 2023 Int J Mol Sci + (''Porphyromonas gingivalis'' (''P. gingiva … ''Porphyromonas gingivalis'' (''P. gingivalis''), a key pathogen in periodontitis, is associated with neuroinflammation. Periodontal disease increases with age; 70.1% of adults 65 years and older have periodontal problems. However, the ''P. gingivalis''- lipopolysaccharide (LPS)induced mitochondrial dysfunction in neurodegenerative diseases remains elusive. In this study, we investigated the possible role of ''P. gingivalis''-LPS in mitochondrial dysfunction during neurodegeneration. We found that ''P. gingivalis''-LPS treatment activated toll-like receptor (TLR) 4 signaling and upregulated the expression of Alzheimer's disease-related dementia and neuroinflammatory markers. Furthermore, the LPS treatment significantly exacerbated the production of reactive oxygen species and reduced the mitochondrial membrane potential. Our study highlighted the pivotal role of ''P. gingivalis''-LPS in the repression of serum response factor (SRF) and its co-factor p49/STRAP that regulate the actin cytoskeleton. The LPS treatment repressed the genes involved in mitochondrial function and biogenesis. ''P. gingivalis''-LPS negatively altered oxidative phosphorylation and glycolysis and reduced total adenosine triphosphate (ATP) production. Additionally, it specifically altered the mitochondrial functions in complexes I, II, and IV of the mitochondrial electron transport chain. Thus, it is conceivable that ''P. gingivalis''-LPS causes mitochondrial dysfunction through oxidative stress and inflammatory events in neurodegenerative diseases.tory events in neurodegenerative diseases.)
Lee 2012 Invest Ophthalmol Vis Sci + (''Purpose'': Following the recent demonstr … ''Purpose'': Following the recent demonstration of increased mitochondrial DNA mutations in lymphocytes of POAG patients, the authors sought to characterize mitochondrial function in a separate cohort of POAG.''Methods'': Using similar methodology to that previous applied to Leber's hereditary optic neuropathy (LHON) patients, maximal adenosine triphosphate (ATP) synthesis and cellular respiration rates, as well as cell growth rates in glucose and galactose media, were assessed in transformed lymphocytes from POAG patients (n = 15) and a group of age- and sex-matched controls (n = 15).''Results'': POAG lymphoblasts had significantly lower rates of complex-I-driven ATP synthesis, with preserved complex-II-driven ATP synthesis. Complex-I driven maximal respiration was also significantly decreased in patient cells. Growth in galactose media, where cells are forced to rely on mitochondrial ATP production, revealed no significant differences between the control and POAG cohort.''Conclusions'': POAG lymphoblasts in the study cohort exhibited a defect in complex-I of the oxidative phosphorylation pathway, leading to decreased rates of respiration and ATP production. Studies in LHON and other diseases have established that lymphocyte oxidative phosphorylation measurement is a reliable indicator of systemic dysfunction of this pathway. While these defects did not impact lymphoblast growth when the cells were forced to rely on oxidative ATP supply, the authors suggest that in the presence of a multitude of cellular stressors as seen in the early stages of POAG, these defects may lead to a bioenergetic crisis in retinal ganglion cells and an increased susceptibility to cell death.an increased susceptibility to cell death.)
Li 2018 Gene + (''SURF1'' is an assembly factor of mitocho … ''SURF1'' is an assembly factor of mitochondrial complex IV, and its mutations are the primary cause of Leigh syndrome in infants. To date, over 100 ''SURF1'' mutations have been reported worldwide, but the spectrum of the ''SURF1'' mutations in China remains unclear. Here, using next-generation sequencing targeting mitochondrial protein-coding sequences, we sequenced 178 patients suspected to have mitochondrial diseases. Fifteen ''SURF1'' mutations were identified in 12 Leigh syndrome patients, of which three, c.465_466delAA, c.532A > T, and c.826_827ins AGCATCTGCAGTACATCG, were newly described. The percentage of ''SURF1'' frameshift mutations (6/28, 21.4%) we detected in Chinese population is higher than other studies (21/106, 19.8%) with different populations, however, the percentage of missense mutations is lower in this study than others (4/28, 14.3% VS. 25/106, 23.6%). Since complex IV can be detected in cells carrying missense mutations (3/8) but not in cells carrying null mutations (0/4) by using cell model-based complementation assay, our results indicate that ''SURF1'' mutations may be associated with worse clinical outcome in Chinese patients than other populations. However, studies with larger sample size are needed to verify this conclusion. Additionally, we found that the frameshift mutations resulting in protein truncation closer to the C-terminus are not associated with better disease prognosis. Lastly, we found that determining the levels of complex IV assembly using cell models or lymphocyte analysis rather than invasive muscle and skin fibroblast biopsy, may help predict disease progression in Leigh syndrome patients.sease progression in Leigh syndrome patients.)
Rosenfeld 2003 Yeast + (''Saccharomyces cerevisiae'' is a facultat … ''Saccharomyces cerevisiae'' is a facultative anaerobe devoid of mitochondrial alternative oxidase. In this yeast, the structure and biogenesis of the respiratory chain, on the one hand, and the functional interactions of oxidative phosphorylation with the cellular energetic metabolism, on the other, are well documented. However, to our knowledge, the molecular aspects and the physiological roles of the non-respiratory pathways that utilize molecular oxygen have not yet been reviewed. In this paper, we review the various non-respiratory pathways in a global context of utilization of molecular oxygen in S. cerevisiae. The roles of these pathways are examined as a function of environmental conditions, using either physiological, biochemical or molecular data. Special attention is paid to the characterization of the so-called 'cyanide-resistant respiration' that is induced by respiratory deficiency, catabolic repression and oxygen limitation during growth. Finally, several aspects of oxygen sensing are discussed.l aspects of oxygen sensing are discussed.)
Oliveira 2016 PLOS ONE + (''Schistosoma mansoni'', one of the causat … ''Schistosoma mansoni'', one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along ''S. mansoni'' development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by ''S. mansoni'' metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult ''S. mansoni'' worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult ''S. mansoni'' worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute to redox biology among parasite sexes.ute to redox biology among parasite sexes.)
Konickova 2014 Annals Hepatol + (''Spirulina platensis'' is a blue-green al … ''Spirulina platensis'' is a blue-green alga used as a dietary supplement because of its hypocholesterolemic properties. Among other bioactive substances, it is also rich in tetrapyrrolic compounds closely related to bilirubin molecule, a potent antioxidant and anti-proliferative agent. The aim of our study was to evaluate possible anticancer effects of ''S. platensis'' and ''S. platensis''-derived tetrapyrroles using an experimental model of pancreatic cancer. The anti-proliferative effects of ''S. platensis'' and its tetrapyrrolic components [phycocyanobilin (PCB) and chlorophyllin, a surrogate molecule for chlorophyll A] were tested on several human pancreatic cancer cell lines and xenotransplanted nude mice. The effects of experimental therapeutics on mitochondrial reactive oxygen species (ROS) production and glutathione redox status were also evaluated. Compared to untreated cells, experimental therapeutics significantly decreased proliferation of human pancreatic cancer cell lines ''in vitro'' in a dose-dependent manner (from 0.16 g•L-1 [''S. platensis''], 60 μM [PCB], and 125 μM [chlorophyllin], ''p''<0.05). The anti-proliferative effects of ''S. platensis'' were also shown ''in vivo'', where inhibition of pancreatic cancer growth was evidenced since the third day of treatment (''p''<0.05). All tested compounds decreased generation of mitochondrial ROS and glutathione redox status (''p''=0.0006; 0.016; and 0.006 for ''S. platensis'', PCB, and chlorophyllin, respectively). In conclusion, ''S. platensis'' and its tetrapyrrolic components substantially decreased the proliferation of experimental pancreatic cancer. These data support a chemopreventive role of this edible alga. Furthermore, it seems that dietary supplementation with this alga might enhance systemic pool of tetrapyrroles, known to be higher in subjects with Gilbert syndrome.roles, known to be higher in subjects with Gilbert syndrome.)
Uribe-Alvarez 2016 Abstract MitoFit Science Camp 2016 + (''Staphylcoccus epidermidis'' does not inv … ''Staphylcoccus epidermidis'' does not invade healthy tissues, however, it has been identified as a cause of nosocomial infections due to its ability to form biofilms on polymer surfaces [1]. ''S. epidermidis'' can be grown at different oxygen concentrations ([O2]), including mammalian skin where [O2] ranges from 3-5% and in anaerobic altered tissues [2,3]. Biofilm formation of ''S. epidermidis'' and its respiratory chain components grown in aerobic, microaerobic and anaerobic conditions were evaluated by in-gel activities, enzymatic activities, spectrophotometry and oxymetry. Varying [O2] modified both biofilm formation and the components in the respiratory chain: At high [O2], little tendency to form biofilms was observed. ''S. epidermidis'' expressed glycerol-3-phosphate, pyruvate, ethanol and succinate dehydrogenases; and cyt bo and aa3. Under micro-aerobiosis, biofilm formation increased slightly; pyruvate, ethanol, glycerol-3-phosphate and succinate dehydrogenase decreased; aa3 cyt was not detected; Under anaerobiosis high biofilm-formation and low ethanol and pyruvate dehydrogenase activities were found; anaerobic nitrate dehydrogenase activity was detected. Aerobic-grown cells with cyanide increased biofilm formation. Anaerobic-grown cells with methylamine decreased biofilm formation. Thus, either a decrease in [O2] or the inhibition of the aerobic chain led ''S. epidermidis'' to associate into biofilms. In contrast, high [O2] or inhibition of the anaerobic nitrate reductase prevented biofilm formation suggesting that the enzymes expressed at low to null [O2] are therapeutic targets against biofilm formation by ''S. epidermidis''. expressed at low to null [O2] are therapeutic targets against biofilm formation by ''S. epidermidis''.)
Snow 2015 PLoS One + (''Trichodesmium'' is a biogeochemically im … ''Trichodesmium'' is a biogeochemically important marine cyanobacterium, responsible for a significant proportion of the annual 'new' nitrogen introduced into the global ocean. These non-heterocystous filamentous diazotrophs employ a potentially unique strategy of near-concurrent nitrogen fixation and oxygenic photosynthesis, potentially burdening Trichodesmium with a particularly high iron requirement due to the iron-binding proteins involved in these processes. Iron availability may therefore have a significant influence on the biogeography of Trichodesmium. Previous investigations of molecular responses to iron stress in this keystone marine microbe have largely been targeted. Here a holistic approach was taken using a label-free quantitative proteomics technique (MSE) to reveal a sophisticated multi-faceted proteomic response of Trichodesmium erythraeum IMS101 to iron stress. Increased abundances of proteins known to be involved in acclimation to iron stress and proteins known or predicted to be involved in iron uptake were observed, alongside decreases in the abundances of iron-binding proteins involved in photosynthesis and nitrogen fixation. Preferential loss of proteins with a high iron content contributed to overall reductions of 55-60% in estimated proteomic iron requirements. Changes in the abundances of iron-binding proteins also suggested the potential importance of alternate photosynthetic pathways as Trichodesmium reallocates the limiting resource under iron stress. ''Trichodesmium'' therefore displays a significant and integrated proteomic response to iron availability that likely contributes to the ecological success of this species in the ocean.ical success of this species in the ocean.)
Subrtova 2013 Abstract MiP2013 + (''Trypanosoma brucei'' is a parasitic flag … ''Trypanosoma brucei'' is a parasitic flagellate that causes devastating diseases of humans and lifestock. The infective form dwells in the glucose rich environment of mammalian blood and generate energy solely via glycolysis. In consequence, the bloodstream stage single mitochondrion is highly reduced lacking key Krebs cycle enzymes and traditional cytochrome mediated respiratory chain. Interestingly, the essential mitochondrial membrane potential (Δ''ψ''mt) is maintained by hydrolytic activity of the unique FoF1-ATPase, which contains several trypanosoma specific subunits of unknown function [1].We determined that one of the largest novel subunit, Tb2930 (43 kDa), is membrane-bound and localizes into monomeric and multimeric assemblies of the FoF1-ATPase. RNAi silencing of Tb2930 led to a significant decrease of Δ''ψ''mt and consequently to ''T. brucei'' growth inhibition, indicating that the FoF1-ATPase is not functioning properly even though its structural intergrity seems to be almost unchanged. To further explore the function of this protein, we employed naturally occuring trypanosoma strain that lacks mtDNA (dyskinetoplastic, Dk) including subunit a, an essential component of the Fo-moiety and proton pore. These Dk cells maintain Δ''ψ''mt by electrogenic exchange of ATP4-/ADP3- by the ATP/ADP carrier (AAC) and hydrolytic activity of the soluble F1-ATPase [2]. So far, it has been assumed that only the F1-moiety subunits are present and will be essential for these parasites. Interestingly, glycerol gradient sedimentation and native electrophoresis of Dk mitochondria revealed the presence of high molecular weight ATPase complexes that correspond to the bloodstream stage monomeric and multimeric FoF1-ATPase. Furthermore, the Tb2930 subunit is expressed in Dk cells and co-sediments with these high molecular weight membrane bound complexes. The RNAi study demonstrated that Tb2930 subunit is essential for Dk trypanosoma cells and crucial for maintaining Δ''ψ''mt. Importantly, upon ablation of Tb2930 we observed a shift of the FoF1-ATPase complexes to the lower S-values on glycerol gradient, where the free F1-ATPase sediments, indicating changes in the structural integrity of the Dk FoF1-ATPase. In conclusion, we propose that Tb2930 is responsible for connecting the Dk F1-ATPase to the mitochondrial membrane in the absence of subunit a of the Fo-moiety, thus increasing the efficiency of the functional association between F1-ATPase and AAC.y, thus increasing the efficiency of the functional association between F1-ATPase and AAC.)
Dolezelova 2017 Abstract IOC122 + (''Trypanosoma brucei'' undergoes a complex … ''Trypanosoma brucei'' undergoes a complex life cycle as it alternates between a mammalian host and the blood-feeding insect vector, a tsetse fly. Due to the different environments, the distinct life stages differ in their energy metabolism, i.e. insect stage (procyclic cells, PS) depends on mitochondrial oxidative phosphorylation (OXPHOS) for ATP production while the bloodstream stage (BS) gains energy by aerobic glycolysis. The dramatic switch from the OXPHOS to glycolysis happens during the complex development of the PS in the tsetse fly. This development differentiation is characterized by extensive remodeling of mitochondrion structure and changes in mitochondrial bioenergetics. Importantly, the molecular mechanism behind this process is completely unknown. We have established the ''in vitro'' differentiation system, in which the transition from PS to epimastigotes followed by differentiation to transmission-ready metacylic trypanosomes is triggered by RNA binding protein 6 (RBP6) expression. This ''in vitro'' induced differentiation of PF cells takes 8 days. The appearance of epimastigotes and metacyclic trypanosomes in the culture was mapped using light and fluorescent microscopy. The whole cell proteome of cell culture harvested every day after the RBP6 induction was identified by label-free quantitative mass spectrometry. This proteomic data serves as a resource for further detailed characterization of changes happening in the parasite mitochondrion as well as identification of possible candidates involved in the PS differentiation.idates involved in the PS differentiation.)
Paes 2014 Abstract IOC 2014-04 Schroecken + (''Trypanosoma cruzi'' has a single mitocho … ''Trypanosoma cruzi'' has a single mitochondrion, the main site of reactive oxygen species (ROS) production. Moreover, ''T. cruzi'' epimastigotes proliferate in the presence of heme, which induces ROS formation (Nogueira et al 2011; Lara et al 2007). Therefore, we evaluated heme effect upon mitochondrial ROS formation and mitochondrial membrane potential (ΔΨmt). For that, epimastigotes were incubated with DHE or TMRM with or without heme. After this, FCCP and antymicin A (Ama) were added. Mitochondrial ROS production and ΔΨmt were analyzed by flow cytometry. Our results showed that heme duplicated ROS production and induced a 4-fold increase of ΔΨmt. The FCCP addition reversed heme effects upon ROS generation and ΔΨm. Additionally, Ama induced a 2-fold increase of ROS production and 46% increment in ΔΨmt, while co-incubation with heme and AA presented a 3-fold increase upon ROS formation and increase ΔΨmt in 70%. In order to corroborate the involvement of heme in mitochondrial ROS, we incubated the parasites with heme, in the absence or in the presence of mitoTEMPO, a mitochondrial antioxidant. Our results showed that in the presence of this antioxidant greatly decreased heme induced ROS generation. Afterwards, we incubated epimastigotes with heme for 30 min and then, performed a substrate-uncoupler-inhibitor-tritation protocol with rotenone, succinate, ADP, cytocrome c, FCCP and Ama. We were able to detect a decrease in several states, mainly ROUTINE, OXPHOS and reserve capacity, compared to control cells. Finally, we evaluated epimastigotes proliferation with or without heme, H2O2, FCCP, Ama or mitoTEMPO. We observed that low concentrations of H2O2 increased proliferation, while higher concentrations showed deleterious effects upon the cells. FCCP and mitoTEMPO also reversed heme-induced proliferation, whereas, Ama promoted a tripanostatic effect. Taken together, our results strongly suggest that heme modulates ''T. cruzi'' mitochondrial physiology since it promotes mitochondrial ROS production, decreasing mitochondrial states, and enhances the ΔΨmt.tochondrial states, and enhances the ΔΨmt.)
Goncalves 2011 Abstract IOC65 + (''Trypanosoma cruzi'' is a hemoflagellate … ''Trypanosoma cruzi'' is a hemoflagellate protozoan that causes Chagas’ disease. ''T. cruzi'' life-cycle is complex involving different evolutive forms that experience striking differences in their environmental condition. Here we carried out a functional assessment of mitochondrial function in two distinct ''T. cruzi'' forms: the insect stage, epimastigote and the freshly isolated bloodstream trypomastigote. We observed that in comparison to epimastigotes, bloodstream trypomastigotes facilitate electrons entry into the electron transport chain increasing Complex II-III activity. Curiously, cytochrome c oxidase (CIV) activity and the expression of CIV subunit IV were reduced in bloodstream forms, creating an “electron bottleneck” that favored increased electron leak and H2O2 formation. We propose that the oxidative preconditioning provided by this mechanism would confer a protection to the bloodstream trypomastigotes against host immune response. Thus, mitochondrial remodeling during the ''T. cruzi'' life-cycle can represent a key metabolic adaptation for parasite survival in different environments.rasite survival in different environments.)
Santos Bertolini 2018 Thesis + (''Trypanosoma cruzi'' is the etiologic age … ''Trypanosoma cruzi'' is the etiologic agent of Chagas disease, a disorder affecting thousands of people, for which an effective treatment is not available for the chronic phase. Calcium signaling is important for host cell invasion, differentiation, osmoregulation, cell death and flagellar function in trypanosomatids. The influx of calcium into the mitochondria, which is important for intracellular calcium homeostasis, occurs through a mitochondrial calcium uniporter complex (MCUC) and this complex consists of several components, including two regulatory proteins named mitochondrial calcium uptake 1 and 2 (MICU1 and MICU2). In mammalian cells, these proteins are located in the mitochondrial intermembrane space and play a role in sensing cytosolic calcium levels and regulating the MCU opening. Although several MCUC components have been identified in trypanosomes, the mechanism by which it is regulated is still unknown. In this work, we aimed at studying the role of MICU1 and MICU2 in the mitochondrial calcium uptake of ''T. cruzi''. The predicted TcMICU1 and TcMICU2 proteins displayed a mitochondrial targeting signal and EF-hands domains that could be sensitive to changes in cytosolic calcium. We obtained TcMICU1 (MICU1-KO) and TcMICU2 (MICU2-KO) knockout cell lines using the CRISPR/Cas9 system by co-transfecting ''T. cruzi'' epimastigotes with the Cas9/pTREX-n vector (containing a specific sgRNA) and a DNA donor cassette with a blasticidin resistance marker to induce the DNA double-strand break repair by homologous recombination. Additionally, we generated a cell line of ''T. cruzi'' epimastigotes overexpressing TcMICU2 tagged with 2xHA (MICU2-OE) using pTREX-n vector. Such molecular constructs were used to analyze the mutant phenotypes and indicate the functions of these proteins. Our results show that MICU1-KO and MICU2-KO have a significant decrease in the capacity to take up calcium, showing a different regulation when we compared to what has already been described previously in mammals. In the absence of these proteins there is a decrease in the growth rate and respiration rates of epimastigotes, showing how important these two proteins are to this stage of ''T. cruzi''. In addition, MICU1-KO epimastigotes are able to differentiate to metacyclic trypomastigotes in a greater proportion than the control cells while the metacyclogenesis capacity was reduced in MICU2-KO cells. Using the MICU2-OE cell line we demonstrated by immunofluorescence microscopy the mitochondrial localization of MICU2 and that its overexpression does not alter the capacity to take up calcium, besides that it does not affect the mitochondrial membrane potential and parasite growth. We can conclude that the TcMICU1 and TcMICU2 proteins are essential for the regulation of mitochondrial calcium uptake by MCU in ''T. cruzi''. Likewise, the results suggest that both proteins play an important role in the growth and differentiation of epimastigotes.owth and differentiation of epimastigotes.)
Barison 2016 J Bioenerg Biomembr + (''Trypanosoma cruzi'', the aetiological ag … ''Trypanosoma cruzi'', the aetiological agent of Chagas's disease, metabolizes glucose, and after its exhaustion, degrades amino acids as energy source. Here, we investigate histidine uptake and its participation in energy metabolism. No putative genes for the histidine biosynthetic pathway have been identified in genome databases of ''T. cruzi'', suggesting that its uptake from extracellular medium is a requirement for the viability of the parasite. From this assumption, we characterized the uptake of histidine in ''T. cruzi'', showing that this amino acid is incorporated through a single and saturable active system. We also show that histidine can be completely oxidised to CO2. This finding, together with the fact that genes encoding the putative enzymes for the histidine - glutamate degradation pathway were annotated, led us to infer its participation in the energy metabolism of the parasite. Here, we show that His is capable of restoring cell viability after long-term starvation. We confirm that as an energy source, His provides electrons to the electron transport chain, maintaining mitochondrial inner membrane potential and O2 consumption in a very efficient manner. Additionally, ATP biosynthesis from oxidative phosphorylation was found when His was the only oxidisable metabolite present, showing that this amino acid is involved in bioenergetics and parasite persistence within its invertebrate host.oenergetics and parasite persistence within its invertebrate host.)
Saraiva 2022 Pathogens + (''Trypanosoma cruzi'', the causative agent … ''Trypanosoma cruzi'', the causative agent of Chagas disease, faces changes in redox status and nutritional availability during its life cycle. However, the influence of oxygen fluctuation upon the biology of ''T. cruzi'' is unclear. The present work investigated the response of ''T. cruzi'' epimastigotes to hypoxia. The parasites showed an adaptation to the hypoxic condition, presenting an increase in proliferation and a reduction in metacyclogenesis. Additionally, parasites cultured in hypoxia produced more reactive oxygen species (ROS) compared to parasites cultured in normoxia. The analyses of the mitochondrial physiology demonstrated that hypoxic condition induced a decrease in both oxidative phosphorylation and mitochondrial membrane potential (ΔΨm) in epimastigotes. In spite of that, ATP levels of parasites cultivated in hypoxia increased. The hypoxic condition also increased the expression of the hexokinase and NADH fumarate reductase genes and reduced NAD(P)H, suggesting that this increase in ATP levels of hypoxia-challenged parasites was a consequence of increased glycolysis and fermentation pathways. Taken together, our results suggest that decreased oxygen levels trigger a shift in the bioenergetic metabolism of ''T. cruzi'' epimastigotes, favoring ROS production and fermentation to sustain ATP production, allowing the parasite to survive and proliferate in the insect vector.vive and proliferate in the insect vector.)
Souza 2021 PLoS Pathog + (''Trypanosoma cruzi'', the parasite causin … ''Trypanosoma cruzi'', the parasite causing Chagas disease, is a digenetic flagellated protistthat infects mammals (including humans) and reduviid insect vectors. Therefore, ''T. cruzi''must colonize different niches in order to complete its life cycle in both hosts. This fact determines the need of adaptations to face challenging environmental cues. The primary environmental challenge, particularly in the insect stages, is poor nutrient availability. In this regard,it is well known that ''T. cruzi'' has a flexible metabolism able to rapidly switch from carbohydrates (mainly glucose) to amino acids (mostly proline) consumption. Also established hasbeen the capability of ''T. cruzi'' to use glucose and amino acids to support the differentiationprocess occurring in the insect, from replicative non-infective epimastigotes to non-replicative infective metacyclic trypomastigotes. However, little is known about the possibilities ofusing externally available and internally stored fatty acids as resources to survive in nutrient-poor environments, and to sustain metacyclogenesis. In this study, we revisit the metabolic fate of fatty acid breakdown in ''T. cruzi''. Herein, we show that during parasiteproliferation, the glucose concentration in the medium can regulate the fatty acid metabolism. At the stationary phase, the parasites fully oxidize fatty acids. [U-14C]-palmitate can betaken up from the medium, leading to CO2 production. Additionally, we show that electronsare fed directly to oxidative phosphorylation, and acetyl-CoA is supplied to the tricarboxylicacid (TCA) cycle, which can be used to feed anabolic pathways such as the ''de novo'' biosynthesis of fatty acids. Finally, we show as well that the inhibition of fatty acids mobilization intothe mitochondrion diminishes the survival to severe starvation, and impairsmetacyclogenesis.s the survival to severe starvation, and impairs metacyclogenesis.)
Uribe-Alvarez 2018 Microbiologyopen + (''Wolbachia sp.'' has colonized over 70% o … ''Wolbachia sp.'' has colonized over 70% of insect species, successfully manipulatinghost fertility, protein expression, lifespan, and metabolism. Understanding and engineeringthe biochemistry and physiology of ''Wolbachia'' holds great promise for insectvector-borne disease eradication. ''Wolbachia'' is cultured in cell lines, which have longduplication times and are difficult to manipulate and study. The yeast strain''Saccharomyces cerevisiae'' W303 was used successfully as an artificial host for''Wolbachia'' wAlbB. As compared to controls, infected yeast lost viability early, probablyas a result of an abnormally high mitochondrial oxidative phosphorylation activityobserved at late stages of growth. No respiratory chain proteins from ''Wolbachia''were detected, while several ''Wolbachia'' F1F0-ATPasesubunits were revealed. After 5 days outside the cell, Wolbachia remained fully infective against insect cells.the cell, Wolbachia remained fully infective against insect cells.)
38th Mahabaleshwar Seminar + ('Mitochondria, Metabolism and Energetics': [[Media:MiPNet18.14 IOC85 Mahabaleshwar.pdf|'''38th Mahabaleshwar Seminar''']], [http://www.tifr.res.in/~dbsconf/mito2014/Home.html mito2014], including '''[[MiPNet18.14 | 85th OROBOROS O2k-Workshop]]'''.)
Paeaebo 2014 Basic Books + ('The Neanderthals live on in many of us to … 'The Neanderthals live on in many of us today' (p 199).Neanderthal Man tells the story of geneticist Svante Pääbo's mission to answer this question, and recounts his ultimately successful efforts to genetically define what makes us different from our Neanderthal cousins. Beginning with the study of DNA in Egyptian mummies in the early 1980s and culminating in the sequencing of the Neanderthal genome in 2010, Neanderthal Man describes the events, intrigues, failures, and triumphs of these scientifically rich years through the lens of the pioneer and inventor of the field of ancient DNA.We learn that Neanderthal genes offer a unique window into the lives of our hominin relatives and may hold the key to unlocking the mystery of why humans survived while Neanderthals went extinct. Drawing on genetic and fossil clues, Pääbo explores what is known about the origin of modern humans and their relationship to the Neanderthals and describes the fierce debate surrounding the nature of the two species' interactions. His findings have not only redrawn our family tree, but recast the fundamentals of human history—the biological beginnings of fully modern ''Homo sapiens'', the direct ancestors of all people alive today.A riveting story about a visionary researcher and the nature of scientific inquiry, Neanderthal Man offers rich insight into the fundamental question of who we are.to the fundamental question of who we are.)
Sipos 2005 Cell Mol Neurobiol + ((1) Endothelial cells are permanently chal … (1) Endothelial cells are permanently challenged by altering pH in the blood, and oxidative damage could also influence the intracellular pH (pH(i)) of the endothelium. Cerebral microvascular endothelial cells form the blood-brain barrier (BBB) and pH(i) regulation of brain capillary endothelial cells is important for the maintenance of BBB integrity. The aim of this study was to address the pH regulatory mechanisms and the effect of an acute exposure to hydrogen peroxide (H2O2) on the pH regulation in primary rat brain capillary endothelial (RBCE) cells The RBCE monolayers were loaded with the fluorescent pH indicator BCECF and pH(i) was monitored by detecting the fluorescent changes. (2) The steady-state pH(i) of RBCE cells in HEPES-buffer (6.83 +/- 0.1) did not differ significantly from that found in bicarbonate-buffered medium (6.90 +/- 0.08). Cells were exposed to NH4CI to induce intracellular acidification and then the recovery to resting pH was studied. Half-recovery time after NH4Cl prepulse-induced acid load was significantly less in the bicarbonate-buffered medium than in the HEPES-medium, suggesting that in addition to the Na+ / H+ exchanger, HCO3- / Cl- exchange mechanism is also involved in the restoration of pH(i) after an intracellular acid load in primary RBCE cells. We used RT-PCR-reactions to detect the isoforms of Na+ / H+ exchanger gene family (NHE). NHE-1 -2, -3 and -4 were equally present, and there was no significant difference in the relative abundance of the four transcripts in these cells. (3) No pH(i) recovery was detected when the washout after an intracellular acid load occurred in nominally Na+ -free HEPES-buffered medium or in the presence of 10 microM 5-(N-ethyl-N-isopropyl)amiloride (EIPA), a specific inhibitor of Na+ / H+ exchanger. The new steady-state pH(i) were 6.37 +/- 0.02 and 6.60 +/- 0.02, respectively. (4) No detectable change was observed in the steady-state pH(i) in the presence of 100 microM H2O2; however, recovery from NH4Cl prepulse-induced intracellular acid load was inhibited when H2O2 was present in 50 or 100 microM concentration in the HEPES-buffered medium during NH4Cl washout. These data suggest that H2O2 is without effect on the activity of Na+ / H+ exchanger at rest, but could inhibit the function of the exchanger after an intracellular acid load.xchanger after an intracellular acid load.)
MiPNet25.14 TPP Analysis Template + ((2020) Excel template for TPP data analys … (2020) Excel template for TPP data analysis. Mitochondr Physiol Network 25.14(01):1-8. <div style="padding:0px;border: 1px solid #aaaaaa;margin-bottom:0px;margin-right:10px"><div style="font-size:100%;font-weight:bold;padding:0.2em;padding-right: 0.4em;padding-left: 0.4em;background-color:#eeeeee;border-bottom:1px solid #aaaaaa;text-align:left;">[[Image:O2k-support system.jpg|right|150px|link=http://wiki.oroboros.at/index.php/O2k-technical_support_and_open_innovation|O2k-technical support and open innovation]]: <big>Open the '''pdf document''' above.</big></div><div style="background-color:#ffffff;padding-top:0.2em;padding-right: 0.4em;padding-bottom: 0.2em;padding-left: 0.4em;">::::» Current O2k-series: '''[https://www.oroboros.at/index.php/product-category/products/o2k-packages/ NextGen-O2k Series XB and O2k Series J]'''::::» Current software versions DatLab 8.0: [[MitoPedia: DatLab]]::::* ''Further details:'' '''» [[MitoPedia: O2k-Open Support]]'''</div></div>:» Product: [[DatLab]], [[Oroboros O2k]], [[Oroboros O2k-Catalogue |O2k-Catalogue]]oboros O2k-Catalogue |O2k-Catalogue]])
Kagawa 1971 J Biol Chem + ( * Amorphous membrane fragments depleted i … * Amorphous membrane fragments depleted in P-lipids and cytochrome oxidase were isolated from bovine heart mitochondria and were reconstituted with P-lipids and coupling factors to yield vesicular structures. These vesicles catalyzed a 32Pi—ATP exchange and showed an induced enhancement of anilinonaphthalene sulfonate fluorescence on addition of ATP* 32Pi—ATP exchange and fluorescence enhancement were abolished by uncouplers of oxidative phosphorylation and by energy transfer inhibitors. The ATPase activity was inhibited by energy transfer inhibitors, but stimulated by uncouplers or by the combined action of nigericin and valinomycin in the presence of K+. Both ATPase activity and 32Pi—ATP exchange were inhibited by a specific antibody against coupling factor 1.* It was shown that the reconstitution of vesicular structures with functional activity required several hours. Rapid reconstitution resulted in inactive vesicles. Evidence for the formation of new vesicles from solubilized P-lipids was obtained by demonstrating inclusion of macromolecules such as 14C-labeled inulin or ferritin which could not be removed by washing.itin which could not be removed by washing. )
Cannon 2015 Fatty Acid Oxidation O2k-Network Discussion Forum + ( *Saponin permeabilized skeletal muscle fi … *Saponin permeabilized skeletal muscle fiber bundles*'''Protocol''':#0.5mM Malate#50 µM palmitoyl-CoA + 2mM carnitine#5mM ADP#From here on out, various combinations for titration protocol*Coupling states:#LEAK_M+Palmitoylcarnitine#P_M+Palmitoylcarnitine#P_M+Palmitoylcarnitine+S#E_O+CCCP titrations#E_S+Rot#ROX_AntimycinA_O+CCCP titrations #E_S+Rot #ROX_AntimycinA )
Nernst 1921 Nobel Lecture + (.. From the start of my scientific career … .. From the start of my scientific career the galvanic cell, the first form of which, the Volta pile, popularized physics in a single stroke and at the same time presented us with so many problems, appeared to me to merit especially further study. ..It was particularly disillusioning to find a man like Helmholtz returning repeatedly throughout his scientific career to his first love, the galvanic cell, which he had courted in his great youthful work "Erhaltung der Kraft" (The conservation of energy), without however succeeding in finding a satisfactory solution.As often in natural science the picture changed quite suddenly. New fruitful concepts appeared, through the interplay and extension of which most of the darkness has been to a large extent dispelled in a single stroke. Such means were Van ’t Hoff’s theory of osmotic pressure, Arrhenius’ theory of electrolytic dissociation, and finally many new approaches to the treatment of chemical equilibria, which, brilliantly presented, are to be found scattered throughout the first edition of Ostwald’s "Lehrbuch der Allgemeinen Chemie" (Textbook of general chemistry). So there arose in 1889 the osmotic theory of galvanic current generation, which has not been seriously challenged since it was put forward more than thirty years ago and has undergone no appreciable elaboration since its acceptance, surely a clear sign that it has so far satisfied scientific needs. ..The osmotic theory of current generation stipulates moreover that when a metal ion concentration is higher than consistent with the solution tension of the particular metal, on immersion of the metal, ions of the relevant metal electrode must go into solution, while conversely they must settle on the electrode when the reverse is the case.he electrode when the reverse is the case.)
Estabrook 1967 Methods Enzymol + (.. The convenience and simplicity of the p … .. The convenience and simplicity of the polarographic 'oxygen electrode' technique for measuring rapid changes in the rate of oxygen utilization by cellular and subcellular systems is now leading to its more general application in many laboratories. The types and design of oxygen electrodes vary, depending on the invetigator's ingenuity and specific requirements of the system under investigation.rements of the system under investigation.)
Gnaiger 1997 Transplant Proc + (0RGAN PRESERVATION under hypothermic ische … 0RGAN PRESERVATION under hypothermic ischemia is enhanced by storage solutions that protect the vascular endothelium from ischemia-reperfusion injury. Ischemia-reperfusion injury leads to primary graft failure and chronic rejection, and is commonly assessed by measuring endothelial activation and damage of the endothelial plasma membrane. However, corresponding primary intracellular events are little understood compared with the secondary cytokine/adhesion molecule cascade and inflammatory responses.1, 2 Because protection of intracellular and cell membrane function is fundamental for further improvement of organ preservation, we developed highresolution respirometry as a sensitive diagnostic test for mitochondrial and plasma membrane competence.3 Whereas the plasma membrane remained impermeable after clinically relevant cold storage times of 8 hours and 20 to 60 minutes of reoxygenation, mitochondrial function was impaired at several steps of the respiratory chain.l function was impaired at several steps of the respiratory chain.)
Majiene 2019 Nutrients + (1,4-naphthoquinones, especially juglone, a … 1,4-naphthoquinones, especially juglone, are known for their anticancer activity. However, plumbagin, lawsone, and menadione have been less investigated for these properties. Therefore, we aimed to determine the effects of plumbagin, lawsone, and menadione on C6 glioblastoma cell viability, ROS production, and mitochondrial function.Cell viability was assessed spectrophotometrically using metabolic activity method, and by fluorescent Hoechst/propidium iodide nuclear staining. ROS generation was measured fluorometrically using DCFH-DA. Oxygen uptake rates were recorded by the high-resolution respirometer Oxygraph-2k.Plumbagin and menadione displayed highly cytotoxic activity on C6 cells (IC50 is 7.7 ± 0.28 μM and 9.6 ± 0.75 μM, respectively) and caused cell death by necrosis. Additionally, they increased the amount of intracellular ROS in a concentration-dependent manner. Moreover, even at very small concentrations (1-3 µM), these compounds significantly uncoupled mitochondrial oxidation from phosphorylation impairing energy production in cells. Lawsone had significantly lower viability decreasing and mitochondria-uncoupling effect, and exerted strong antioxidant activity.Plumbagin and menadione exhibit strong prooxidant, mitochondrial oxidative phosphorylation uncoupling and cytotoxic activity. In contrast, lawsone demonstrates a moderate effect on C6 cell viability and mitochondrial functions, and possesses strong antioxidant properties.unctions, and possesses strong antioxidant properties.)
Leyssens 1996 J Physiol + (1. As ATP has a higher affinity for Mg2+ t … 1. As ATP has a higher affinity for Mg2+ than ADP, the cytosolic magnesium concentration rises upon ATP hydrolysis. We have therefore used the Mg(2+)-sensitive fluorescent indicator Magnesium Green (MgG) to provide an index of changing ATP concentration in single rat cardiomyocytes in response to altered mitochondrial state. 2. In response to FCCP, [Mg2+]i rose towards a plateau coincident with the progression to rigor, which signals ATP depletion. Contamination of the MgG signal by changes in intracellular free Ca2+ concentration (the KD of MgG for Ca2+ is 4.7 microM) was excluded by simultaneous measurement of [Ca2+]i and [Mg2+]i in cells dual loaded with fura-2 and MgG. The response to FCCP was independent of external Mg2+, confirming an intracellular source for the rise in [Mg2+]i. 3. Simultaneous measurements of mitochondrial NAD(P)H autofluorescence and mitochondrial potential (delta psi m; .-1 fluorescence) and of autofluorescence and MgG allowed closer study of the relationship between [Mg2+]i and mitochondrial state. Oligomycin abolished the FCCP-induced rise in [Mg2+]i without altering the change in autofluorescence. Thus, the rise in [Mg2+]i in response to FCCP is consistent with the release of intracellular Mg2+ following ATP hydrolysis by the mitochondrial F1F0-ATPase. 4. The rise in [Mg2+]i was correlated with cell-attached recordings of ATP-sensitive K+ channel (KATP) activity. In response to FCCP, an increase in KATP channel activity was seen only as [Mg2+]i reached a plateau. In response to blockade of mitochondrial respiration and glycolysis with cyanide (CN-) and 2-deoxyglucose (DOG), [Mg2+]i rose more slowly but again KATP channel opening increased only when [Mg2+]i reached a plateau and the cells shortened. 5. Oligomycin decreased the rate of rise of [Mg2+]i delayed the onset of rigor and increased the rate of mitochondrial depolarization in response to CN-_DOG. Thus, with blockade of mitochondrial respiration delta psi m is maintained by the mitochondrial F1F0-ATPase at the expense of ATP reserves. 6. In response to CN-_DOG, the initial rise in [Mg2+]i was accompanied by a small rise in [Ca2+]i. After [Mg2+]i reached a plateau and rigor developed, [Ca2+]i rose progressively. On reperfusion, in hypercontracted cells, [Ca2+]i recovered before [Mg2+]i and [ca2+]i oscillations were sustained while [Mg2+]i decreased. Thus on reperfusion, full recovery of [ATP]i is slow, but the activation of contractile elements and the restoration of [Ca2+]i does not require the re-establishment of millimolar concentrations of ATP.hment of millimolar concentrations of ATP.)
Satoh 1995 Br J Pharmacol + (1. Effects of 3-hydroxy-3-methylglutaryl c … 1. Effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, pravastatin and simvastatin, on the myocardial level of coenzyme Q10, and on mitochondrial respiration were examined in dogs. 2. Either vehicle (control), pravastatin (4 mg kg-1 day-1), or simvastatin (2 mg kg-1 day-1) was administered orally for 3 weeks. First, the myocardial tissue level of coenzyme Q10 was determined in the 3 groups. Second, ischaemia was induced by ligating the left anterior descending coronary artery (LAD) in anaesthetized open chest dogs, pretreated with the inhibitors. After 30 min of ischaemia, nonischaemic and ischaemic myocardium were removed from the left circumflex and LAD regions, respectively, and immediately used for isolation of mitochondria. The mitochondrial respiration was determined by polarography, with glutamate and succinate used as substrates. 3. Simvastatin significantly decreased the myocardial level of coenzyme Q10, but pravastatin did not. 4. Ischaemia decreased the mitochondrial respiratory control index (RCI) in both groups. Significant differences in RCI between nonischaemic and ischaemic myocardium were observed in the control and simvastatin-treated groups. 5. Only in the simvastatin-treated group did ischaemia significantly decrease the ADP/O ratio, determined with succinate. 6. The present results indicate that simvastatin but not pravastatin may cause worsening of the myocardial mitochondrial respiration during ischaemia, probably because of reduction of the myocardial coenzyme Q10 level.tion of the myocardial coenzyme Q10 level.)
Chance 1962 J Biol Chem + (1. In succinate oxidation reactivated by a … 1. In succinate oxidation reactivated by a low concentration of adenosine triphosphate, addition of small amounts of adenosine diphosphatc will lead to reestablishment of the inhibited state of succinate oxidation after a short burst of respiration.2. The inhibited state is not relieved by either phosphate or phosphate acceptors. 3. The inhibition is closely correlated with a high degree of oxidation of mitochondrial reduced diphosphopyridine nucleotide, which occurs immediately on addition of adenosine diphosphate and is followed by the inhibition of succinate oxidation after the oxidation or rather small amounts of succinate. 4. Oxidation of more than approximately two-thirds of the total diphosphopyridinc nuclcotide (DPN) reducible by succinate and adenosine triphosphate eventually leads to inhibition of succinate oxidation. 5. Based on independent evidence for a compartmentation of mitochondrial pyridine nucleotide (approximately one-third available to DPN-linked substrates), it is proposed that inhibi- tion occurs when oxidation of DPN in the compartment available to malate causes oxaloacetate formation sufficient to inhibit succinate oxidation. 6. The general possibility of DPN control of malate oxidation is considered with respect to the whole question of oxaloacetate regulation of the citric acid cycle.etate regulation of the citric acid cycle.)
Hatefi 1962 J Biol Chem-XLII + (1. It has been shown that the electron tra … 1. It has been shown that the electron transfer system in beef heart mitochondria may be reconstituted either totally or in any desired sequential segment by appropriate combinations of two or more of the four primary complexes that have been isolated in highly purified form in this laboratory. 2. The four enzyme systems that collectively comprise the complete machinery for transfer of electrons from reduced diphosphopyridine nucleotide (DPNH; =NADH) and succinate to oxygen re: I, DPNH-coenzyme Q reductase; II, succinic-coenzyme Q reductase; III, QH2-cytochrome ''c'' reductase; and IV, cytochrome ''c'' reductase. The specific inhibitors of each complex have been studied. 3. By appropriate combinations of the primary complexes the following secondary activities have been reconstituted: V, DPNH-cytochrome ''c'' reductase; VI, succinic-cytochrome ''c'' reductase; VII, DPNH, succinic-cytochrome c reductase; VIII, DPNH oxidase; IX, succinic oxidase; and X, DPNH, succinic oxidase activity. The general oxidation-reduction properties of the reconstituted systems, both in the presence and the absence of the usual specific inhibitors of the electron transfer system, are essentially the same as those found for the same activities in the intact mitochondria and in the integrated particles derived therefrom. 4. The reconstituted activities are quite stable to repeated freezing, thawing, and storage at -2O °C, and for the most part, when once formed, are not dissociated by dilution of the mixture or by centrifugation. The evidence supporting the conclusion that reconstitution necessarily involves a particle-particle interaction is discussed.article-particle interaction is discussed.)
Opalka 2004 Br Poult Sci + (1. M. iliotibialis (MIT) and M. pectoralis … 1. M. iliotibialis (MIT) and M. pectoralis (MP) of the BUT Big 6 and Kelly BBB turkey were characterised with respect to physical properties, mitochondrial function, metabolic state, morphology and meat quality.2. Mitochondrial enzyme activity and respiration rates in MP declined with increasing age while glycolytic enzyme activity remained nearly constant.3. There were no major differences between BUT Big 6 and Kelly BBB with respect to histological, histochemical or biochemical variables. In spite of the greater adult weight of BUT Big 6, body proportion was equal in both strains.4. In agreement with the histochemical findings MIT showed higher oxidative capacities, while glycolytic enzyme activity was higher in MP.5. Pyruvate was the best substrate for oxidative phosphorylation in MIT, but not in MP. Pyruvate dehydrogenase (PDH) activity was up to 15 times less in MP and blood lactate was correlated with intramuscular pH.6. Turkey breast muscle was restricted in its ability to oxidise pyruvate, especially in those animals that tended to develop intramuscular acidosis post mortem.7. It is concluded that the ''in vivo'' metabolic environment results in acidosis and impaired meat quality, at least in turkey M. pectoralis.quality, at least in turkey M. pectoralis.)
Claude 1946 J Exp Med + (1. Materials and technical procedures invo … 1. Materials and technical procedures involved in the preparation of liver suspensions have been described and discussed. 2. Liver extracts prepared by the present method appear to contain almost exclusively elements of cytoplasmic origin and can be considered to represent, on a large scale, the cytoplasm of liver cells.large scale, the cytoplasm of liver cells.)
Wilson 1970 Biochim Biophys Acta + (1. Oxidation of NADH by fumarate coupled t … 1. Oxidation of NADH by fumarate coupled to synthesis of ATP was found to occur in cyanide-poisoned rat heart submitochondrial particles. The reaction was inhibited by amytal, thenoyltrifluoroacetone and malonate, indicating the involvement of a portion of the electron transfer chain.2. Cytochrome b became oxidized (while the other cytochromes remained reduced) during the oxidation of NADH by fumarate, suggesting that cytochrome b is part of the reaction pathway.3. Succinate was recovered as the reaction product and accounted for the NADH oxidized.4. The P/2e ratios indicate that one ATP was produced for each pair of electrons transferred to fumarate.5. The reaction was also demonstrated to be present in liver and gastrocnemius muscle of rat. The reaction rate in heart was 2.0 times that of gastrocnemius and 3.3 times that of liver. These differences are not related to the activities of NADH or succinate dehydrogenase.6. The ubiquitous nature of this reaction suggests that it could serve as an important physiological mechanism for generating extra glycolytic energy during periods of anoxia.lycolytic energy during periods of anoxia.)
Boveris 1973 Biochem J + (1. Pigeon heart mitochondria produce H(2)O … 1. Pigeon heart mitochondria produce H(2)O(2) at a maximal rate of about 20 nmol/min per mg of protein. 2. Succinate-glutamate and malate-glutamate are substrates which are able to support maximal H(2)O(2) production rates. With malate-glutamate, H(2)O(2) formation is sensitive to rotenone. Endogenous substrate, octanoate, stearoyl-CoA and palmitoyl-carnitine are by far less efficient substrates. 3. Antimycin A exerts a very pronounced effect in enhancing H(2)O(2) production in pigeon heart mitochondria; 0.26 nmol of antimycin A/mg of protein and the addition of an uncoupler are required for maximal H(2)O(2) formation. 4. In the presence of endogenous substrate and of antimycin A, ATP decreases and uncoupler restores the rates of H(2)O(2) formation. 5. Reincorporation of ubiquinone-10 and ubiquinone-3 to ubiquinone-depleted pigeon heart mitochondria gives a system in which H(2)O(2) production is linearly related to the incorporated ubiquinone. 6. The generation of H(2)O(2) by pigeon heart mitochondria in the presence of succinate-glutamate and in metabolic [[State 4]] has an optimum pH value of 7.5. In States 1 and 3u, and in the presence of antimycin A and uncoupler, the optimum pH value is shifted towards more alkaline values. 7. With increase of the partial pressure of O(2) to the hyperbaric region the formation of H(2)O(2) is markedly increased in pigeon heart mitochondria and in rat liver mitochondria. With rat liver mitochondria and succinate as substrate in State 4, an increase in the ''p''O(2) up to 1.97 MPa (19.5 atm) increases H(2)O(2) formation 10-15-fold. Similar ''p''O(2) profiles were observed when rat liver mitochondria were supplemented either with antimycin A or with antimycin A and uncoupler. No saturation of the system with O(2) was observed up to 1.97 MPa (19.5 atm). By increasing the ''p''O(2) to 1.97 MPa (19.5atm), H(2)O(2) formation in pigeon heart mitochondria with succinate as substrate increased fourfold in metabolic State 4, with antimycin A added the increase was threefold and with antimycin A and uncoupler it was 2.5-fold. In the last two saturation of the system with oxygen was observed, with an apparent ''K''(m) of about 71 kPa (0.7-0.8 atm) and a ''V''(max) of 12 and 20 nmol of H(2)O(2)/min per mg of protein. 8. It is postulated that in addition to the well-known flavin reaction, formation of H(2)O(2) may be due to interaction with an energy-dependent component of the respiratory chain at the cytochrome ''b'' level.atory chain at the cytochrome ''b'' level.)
Mitchell 1967 Biochem J + (1. Pulses of acidity of the outer aqueous … 1. Pulses of acidity of the outer aqueous phase of rat liver mitochondrial suspensions induced by pulses of respiration are due to the translocation of H(+) (or OH(-)) ions across the osmotic barrier (M phase) of the cristae membrane and cannot be attributed to the formation (with acid production) of a chemical intermediate that subsequently decomposes. 2. The effective quantity of protons translocated per bivalent reducing equivalent passing through the succinate-oxidizing and beta-hydroxybutyrate-oxidizing spans of the respiratory chain are very close to 4 and 6 respectively. These quotients are constant between pH5.5 and 8.5 and are independent of changes in the ionic composition of the mitochondrial suspension medium provided that the conditions permit the accurate experimental measurement of the proton translocation. 3. Apparent changes in the -->H(+)/O quotients may be induced by conditions preventing the occurrence of the usual backlash; these apparent changes of -->H(+)/O are attributable to a very fast electrically driven component of the decay of the acid pulses that is not included in the experimental extrapolations. 4. Apparent changes in the -->H(+)/O quotients may also be induced by the presence of anions, such as succinate, malonate and phosphate, or by cations such as Na(+). These apparent changes of -->H(+)/O are due to an increase in the rate of the pH-driven decay of the acid pulses. 5. The uncoupling agents, 2,4-dinitrophenol, carbonyl cyanide p-trifluoromethoxyphenylhydrazone and gramicidin increase the effective proton conductance of the M phase and thus increase the rate of decay of the respiration-driven acid pulses, but do not change the initial -->H(+)/O quotients. The increase in effective proton conductance of the M phase caused by these uncouplers accounts quantitatively for their uncoupling action; and the fact that the initial -->H(+)/O quotients are unchanged shows that uncoupler-sensitive chemical intermediates do not exist between the respiratory-chain system and the effective proton-translocating mechanism. 6. Stoicheiometric acid-base changes associated with the activity of the regions of the respiratory chain on the oxygen side of the rotenone- and antimycin A-sensitive sites gives experimental support for a suggested configuration of loop 3.xperimental support for a suggested configuration of loop 3.)
Claude 1944 J Exp Med + (1. Rat tumor extracts, containing chiefly … 1. Rat tumor extracts, containing chiefly the cytoplasmic constituents of leukemic cells, were fractionated into three main portions, the different components separating in the centrifuge according to size. 2. Mitochondria were isolated by centrifugation at relatively low speed. Elementary composition of purified mitochondria was found to correspond to about 11.5 per cent nitrogen, 1.6 per cent phosphorus, and 27 per cent lipids. Phosphorus and nitrogen content of the lipid portion suggests that as much as 75 to 80 per cent of the lipids of mitochondria is represented by phospholipids. Tests for ribose nucleic acid were positive. 3. Microsomes were separated by means of centrifugation at 18,000 x g. A relation between the high phosphorus content of the microsomes and the marked basophilia of the cytoplasm of leukemic cells is suggested. 4. Phosphorus distribution in the tumor extract, and light absorption analysis of the third fraction, seem to demonstrate that nucleic acid was not present either in a free condition, or in the form of nucleoprotein of relatively low molecular weight. The nature of the results suggests that ribose nucleic acid occurs in the cytoplasm of leukemic cells only in association with formed elements of relatively large size, namely microsomes, and mitochondria.size, namely microsomes, and mitochondria.)
Ernster 1969 Eur J Biochem + (1. Submitochondrial particles were prepare … 1. Submitochondrial particles were prepared from beef‐heart mitochondria by sonication in the presence of EDTA. The particles were lyophilized and repeatedly extracted with pentane until no ubiquinone was found in the extract. Treatment of the ubiquinone‐depleted particles with pentane containing a suitable concentration of ubiquinone (ubiquinone‐50) and subsequent quick washing with ubiquinone‐free pentane resulted in a “re‐incorporation” of ubiquinone in an amount similar to that present in the original particles (3–6 nmoles/mg protein).2. The ubiquinone‐depleted particles exhibited very low or no succinate and NADH oxidase activities, which were restored upon the re‐incorporation of ubiquinone to the levels found in the lyophilized particles before extraction with pentane. Partial (about 50 %) extraction of ubiquinone resulted in markedly decreased succinate and NADH oxidase activities.3. Added cytochrome ''c'' did not replace ubiquinone in restoring the succinate or NADH oxidase activity of ubiquinone‐depleted particles. It stimulated the NADH oxidase, but not the succinate oxidase, activity of the “ubiquinone‐incorporated” particles, but the same stimulation occurred with the lyophilized particles before ubiquinone extraction. The normal, lyophilized, and “ubiquinone‐incorporated” particles contained equal amounts of both total and enzymatically reducible cytochromes.4. In the presence of KCN, NADH reduced the cytochromes, including cytochrome ''b'', only at insignificant rates in the ubiquinone‐depleted particles as compared to the normal and lyophilized preparations, and these rates were greatly stimulated upon the re‐incorporation of ubiquinone. Succinate caused a rapid partial (about 25 %) reduction of cytochrome ''b'', but not of the rest of the cytochromes, in the ubiquinone‐depleted particles. This reduction occurred also in the absence of KCN, and the fraction of cytochrome ''b'', so reduced was not reoxidized when succinate oxidation was inhibited by malonate. Evidence for the occurrence of such an enzymatically non‐oxidizable form of cytochrome ''b'' was also obtained in the normal, lyophilized and “ubiquinone‐incorporated” particles, but, in those cases, this cytochrome ''b'' was reduced by both succinate and NADH. In the presence of antimycin A, all cytochrome ''b'' in the ubiquinone‐depleted particles was rapidly reduced by succinate but not by NADH.5. The normal and lyophilized particles catalyzed a rotenone‐sensitive oxidation of NADH by fumarate. This reaction was completely absent from the ubiquinone‐depleted particles and was restored upon the re‐incorporation of ubiquinone.6. N,N,N′,N′‐Tetramethyl‐p‐phenylenediamine catalyzed an NADH and succinate oxidase activity in antimycin A‐inhibited particles. This NADH oxidase activity was partially sensitive to rotenone in the normal, lyophilized and “ubiquinone‐incorporated” particles, but completely rotenone‐insensitive in the ubiquinone‐depleted particles. All four types of particles were active in catalyzing the antimycin A‐sensitive oxidation of menadiol.7. It is concluded that uniquinone is essential for the interaction of succinate dehydrogenase, NADH dehydrogenase and cytochrome ''b'', and that this interaction is a requisite for the normal function of the respiratory chain. Functionally modified forms of cytochrome ''b'', arising as a consequence of structural damage or antimycin A treatment, are discussed in relation to existing information and proposals concerning the role of cytochrome ''b'' and ubiquinone in electron transport.'b'' and ubiquinone in electron transport.)
Henderson 1969 Biochem J + (1. The action of the antibiotics enniatin … 1. The action of the antibiotics enniatin A, valinomycin, the actin homologues, gramicidin, nigericin and dianemycin on mitochondria, erythrocytes and smectic mesophases of lecithin-dicetyl hydrogen phosphate was studied. 2. These antibiotics induced permeability to alkali-metal cations on all three membrane systems. 3. The ion specificity on each membrane system was the same. 4. Enniatin A, valinomycin and the actins did not induce permeability to protons, whereas nigericin and dianemycin rendered all three membrane systems freely permeable to protons. 5. Several differences were noted between permeability induced by nigericin and that induced by gramicidin. 6. The action of all these antibiotics on mitochondrial respiration could be accounted for by changes in passive ion permeability of the mitochondrial membrane similar to those induced in erythrocytes and phospholipid membranes, if it is assumed that a membrane potential is present in respiring mitochondria.tial is present in respiring mitochondria.)
Harafuji 1980 J Biochem + (1. The apparent binding constant (Kapp(Ca- … 1. The apparent binding constant (Kapp(Ca-G)) for GEDTA (ethylene glycol bis(β-aminoethyl ether)-N, N, N', N'-tetraacetic acid, EGTA) to calcium was determined under conditions of biological significance in the presence of various kinds of pH-buffering agents, using murexide or tetramethylmurexide as a Ca indicator.2. The value of Kapp(Ca-G) at pH 6.80 was 1.0×106M-1 at an ionic strength of 0.114 at 20°C, irrespective of the type of pH-buffering ions. This value is similar to that of Allen, Blinks and Prendergast (1977) (Science 196, 996-998), but still half that calculated from the results of Schwarzenbach, Senn and Anderegg (1957) (Helv. Chim. Acta 40, 1886-1900).3. The value of Kapp(Ca-G) varied according to the following equation as the ionic strength (I) was varied from 0.039 to 0.264:log Kapp(Ca-G)=6.460-[2_??_I/(1+_??_I)-0.4×I] (pH 6.80, 20°C)4. The discrepancy between the present results and previous ones (Ogawa, Y. (1968) J. Biochem. 64, 255-257) may have been due to inadequate regulation of the temperature of the reaction medium in the previous determinations, during which an increase in the temperature of the solution may have occurred.An increase of temperature causes a decrease in the pH of the solution in the presence of histidine, imidazole or Tris-maleate, but causes very little change of pH in the presence of phosphate or maleate.5. The association rate constant for GEDTA with calcium was determined by the stoppedflow method in solutions containing 100mM KCl and 20mM pH-buffering ions at 20°C: the values obtained were 1.4×106M-1s-1 in the presence of MOPS-KOH at pH 6.80; 3.0×106M-1s-1 with imidazole at pH 6.80; 1.0×106M-1s-1 with Tris-maleate at pH 6.80..0×106M-1s-1 with Tris-maleate at pH 6.80.)
Harris 1968 Biochem J + (1. The concentration-dependence of the int … 1. The concentration-dependence of the intramitochondrial accumulation of l-malate and succinate was measured and expressed in the form of adsorption isotherms. The accumulation, however, may arise because of an internal positive potential. 2. The competition for accumulation offered by some other anions, including phosphate, was measured and is expressed conventionally by additional terms in the adsorption equation. 3. The interactions between anions were also studied when one was acting as oxidized substrate. 4. In some examples there is a parallel between the effects of an added anion on both accumulation and oxidation; in other cases chemical participation of the added substance in metabolism is presumed to remove the correlation. 5. It is suggested that by combining kinetic data on penetration with stoicheiometric data on accumulation and specific reaction rates it may be possible to account for the rates of respiration obtained with intact mitochondria. 6. It is possible to show that there is a certain phosphate/substrate ratio for maximum phosphorylation rate with some substrates. This is to be expected when phosphate and substrate compete for accumulation.te and substrate compete for accumulation.)
Koenig 1969 Biochem J + (1. The effects of succinate oxidation on p … 1. The effects of succinate oxidation on pyruvate and also isocitrate oxidation by rat liver mitochondria were studied. 2. Succinate oxidation was without effect on pyruvate and isocitrate oxidation when respiration was maximally activated with ADP. 3. When respiration was partially inhibited by atractylate, succinate oxidation severely inhibited the oxidation of pyruvate and isocitrate. 4. This inhibitory effect of succinate was associated with a two- to three-fold increase in the reduction of mitochondrial NAD(+) but no change in the reduction of cytochrome b. 5. It is concluded that, in the partially energy-controlled state, respiration is more severely inhibited at the first phosphorylating site than at the other two. 6. The effects of succinate oxidation are compared with those of palmitoylcarnitine oxidation. It is concluded that a rapid flow of electrons directly into the respiratory chain at the level of cytochrome b is in itself inadequate to inhibit the oxidation of intramitochondrial NADH. 7. The effects of succinate oxidation on pyruvate oxidation were similar in rat heart and liver mitochondria.milar in rat heart and liver mitochondria.)
Hoek 1970 Biochim Biophys Acta + (1. The kinetics of the efflux of Pi and ma … 1. The kinetics of the efflux of Pi and malate as well as the relationship between Pi transport and intra- and extramitochondrial pH changes were studied in rat-liver mitochondria in the presence of rotenone and oligomycin at different pH's.2. At high pH a fast efflux of Pi from the mitochondria occurs in the first few seconds, followed by a slow re-entry of Pi into the mitochondria. Under the same conditions the exit of malate shows a time lag of 2–4 sec. The exit of malate coincides with the re-entry of Pi.3. In the presence of butylmalonate the exit of endogenous Pi is coupled with a concomitant alkalinization of the mitochondrial matrix space, as calculated from the distribution of 5,5-[14C]dimethyloxazolidine-2,4-dione.4. The stoicheiometry of the Pi-hydroxyl exchange was found to be 1:1.5. The kinetics of Pi transport are consistent with previous observations that there is a direct exchange between OH− and Pi, but not between OH− and malate. The equilibrium distribution of H2PO4− and OH− deviates from the Donnan distribution. This may be explained by assuming a pH-dependent binding of Pi in the mitochondria.pendent binding of Pi in the mitochondria.)
Claude 1945 J Exp Med + (1. The present paper constitutes a prelimi … 1. The present paper constitutes a preliminary study of the morphology of mitochondria by means of electron microscopy.2. The mitochondria that were the subject of this investigation were obtained from a lymphosarcoma of the rat. They were separated from the other components of the leukemic cells by a method of differential centrifugation, and thus made available for direct examination in the electron microscope.3. In the purified form the mitochondria appeared as spherical bodies, the majority of them varying in size approximately from 0.6 to 1.3 µ in diameter.4. Certain aspects of mitochondria in the electron microscope suggest that these elements are surrounded by a differentiated membrane. In some cases the limiting membrane seemed to be responsible for maintaining the general shape of the mitochondria, even when most of the mitochondrial substance had been lost.5. By means of the electron microscope, it is possible to distinguish small elements, 80 to 100 mµ in diameter, within the body of certain mitochondria. Further work is suggested to establish whether these small granules are normal constituents of mitochondria, and what relation may exist between them and ordinary microsomes.6. The nature of mitochondria as morphological units is discussed. Present evidence indicates that mitochondria constitute definite physical entities which can persist in the absence of the cytoplasm.n persist in the absence of the cytoplasm.)
Griffiths 1995 Biochem J + (1. The yield of mitochondria isolated from … 1. The yield of mitochondria isolated from perfused hearts subjected to 30 min ischaemia followed by 15 min reperfusion was significantly less than that for control hearts, and this was associated with a decrease in the rates of ADP-stimulated respiration. 2. The presence of 0.2 microM cyclosporin A (CsA) in the perfusion medium during ischaemia and reperfusion caused mitochondrial recovery to return to control values, but did not reverse the inhibition of respiration. 3. A technique has been devised to investigate whether the Ca(2+)-induced non-specific pore of the mitochondrial inner membrane opens during ischaemia and/or reperfusion of the isolated rat heart. The protocol involved loading the heart with 2-deoxy[3H]glucose ([3H]DOG), which will only enter mitochondria when the pore opens. Subsequent isolation of mitochondria demonstrated that [3H]DOG did not enter mitochondria during global isothermic ischaemia, but did enter during the reperfusion period. 4. The amount of [3H]DOG that entered mitochondria increased with the time of ischaemia, and reached a maximal value after 30-40 min of ischaemia. 5. CsA at 0.2 microM did not prevent [3H]DOG becoming associated with the mitochondria, but rather increased it; this was despite CsA having a protective effect on heart function similar to that shown previously [Griffiths and Halestrap (1993) J. Mol. Cell. Cardiol. 25, 1461-1469]. 6. The non-immunosuppressive CsA analogue [MeAla6]cyclosporin was shown to have a similar Ki to CsA on purified mitochondrial peptidyl-prolyl cis-trans-isomerase and mitochondrial pore opening, and also to have a similar protective effect against reperfusion injury. 7. Using isolated heart mitochondria, it was demonstrated that pore opening could become CsA-insensitive under conditions of adenine nucleotide depletion and high matrix [Ca2+] such as may occur during the initial phase of reperfusion. The apparent increase in mitochondrial [3H]DOG in the CsA-perfused hearts is explained by the ability of the drug to stabilize pore closure and so decrease the loss of [3H]DOG from the mitochondria during their preparation.the mitochondria during their preparation.)
Kearney 1960 J Biol Chem + (1. Unlike other known flavoproteins, in wh … 1. Unlike other known flavoproteins, in which the flavin is relatively loosely bound and is easily liberated by suitable methods of denaturation, in succinic dehydrogenase from beef heart the flavin component is so tightly held that neither treatment with strong acids nor thermal denaturation separates it from the protein.2. Extensive digestion of the purified dehydrogenase with suitable proteolytic enzymes liberates the flavin in an acid-soluble form, which is not, however, identical with known derivatives of riboflavin. The flavin appears in the digest in several chromatographically distinct forms, which may be separated from each other by purification on ion exchange resins or by chromatography on filter paper.3. The main flavin components have been extensively purified and degraded to the mononucleotide and dephosphorylated flavin levels. The dinucleotide contains 1 mole of 5’-adenylic acid, 2 atoms of phosphorus bound in pyrophosphate linkage and 1 mole of ribose. It differs from authentic flavin adenine dinucleotide (FAD) in numerous regards, including its inactivity in the n-amino acid oxidase test, shifted absorption spectrum, shifted pH-fluorescence curve, and in the presence of cationic group(s). After degradation to the mononucleotide and dephosphorylated flavin level, similar differences exist between the resulting compounds and authentic riboflavin 5’-phosphate and riboflavin, respectively. Irradiation in alkali degrades the flavin further, but the resulting compound is not identical with lumiflavin.4. These differences and the greater water solubility of the unphosphorylated compound as compared with riboflavin are best explained by the hypothesis that the flavin in the dehydrogenase is held to a peptide chain by a covalent linkage which survives proteolytic digestion. The compounds in the digest, therefore, would be peptides of FAD, representing fragments of the original enzyme.5. Evidence for the flavin peptide hypothesis has come from the finding that throughout very extensive purification by a variety of methods the flavin is always accompanied by peptide material. In the most purified fraction, believed to be free of contaminating peptides, alanine, serine, threonine, glutamic acid, and valine were present in molar ratio to the flavin and an additional mole of serine was present as N-terminal group. Similar amino acid compositions were found in 2 other samples, purified by different procedures.6. Evidence pertaining to the flavin peptide hypothesis and the possible structure of the flavin is discussed.ible structure of the flavin is discussed.)
Gnaiger 2013 Abstract MiP2013 + (10 years ago the uncoupling hypothesis was … 10 years ago the uncoupling hypothesis was presented for mitochondrial haplogroups of arctic populations suggesting that lower coupling of mitochondrial respiration to ATP production was selected for in favor of higher heat dissipation as an adaptation to cold climates [1,2]. Up to date no actual tests have been published to compare mitochondrial coupling in tissues obtained from human populations with regional mtDNA variations. Analysis of oxidative phosphorylation (OXPHOS) is a major component of mitochondrial phenotyping [3]. We studied mitochondrial coupling in small biopsies of arm and leg muscle of Inuit of the Thule and Dorset haplogroups in northern Greenland compared to Danes from western Europe haplogroups. Inuit had a higher capacity to oxidize fat substrate in leg and arm muscle, yet mitochondrial respiration compensating for proton leak was proportionate with OXPHOS capacity. Biochemical coupling efficiency was preserved across variations in muscle fiber type and uncoupling protein-3 content. After 42 days of skiing on the sea ice in northern Greenland, Danes demonstrated adaptive substrate control through an increase in fatty acid oxidation approaching the level of the Inuit, yet coupling control of oxidative phosphorylation was conserved. Our findings reveal that coupled ATP production is of primary evolutionary significance for muscle tissue independent of adaptations to the cold.ue independent of adaptations to the cold.)
ASMRM 2013 Seoul KR + (10th Conference of the Asian Society of Mitochondrial Research and Medicine - [http://asmrm2013.com/common_files/mess.asp ASMRM 2013], Seoul KR)
MiP2014 + (10th MiP''conference'': Joint IUBMB/MiP Symposium on Mitochondrial Physiology - a Point/Counterpoint Meeting, Obergurgl, Austria; with post-conference workshop '''[[MiPNet19.10 | 95th Oroboros O2k-Workshop]]'''.)
10th Conference of the International Coenzyme Q10 Association 2022 Hamburg DE + (10th Conference of the International Coenzyme Q10 Association, Hamburg, 2022)
10th European Algae Industry Summit 2020 Reykjavik IS + (10th European Algae Industry Summit, Reykjavik, Iceland, 2020)
10th Int CeBiTec Research Conference 2021 Bielefeld DE + (10th Int. CeBiTec Research Conference, Bielefeld, Germany, 2021)
10th International Luebeck Conference on the Pathophysiology and Pharmacology of Erythropoietin and other Hemopoietic Growth Factors + (10th International Luebeck Conference on the Pathophysiology and Pharmacology of Erythropoietin and other Hemopoietic Growth Factors, Lübeck, DE, [https://www.physio.uni-luebeck.de/index.php?id=162 10th International Luebeck Conference])
10th Italian Meeting on Mitochondrial Disease 2020 IT + (10th Italian Meeting on Mitochondrial Diseases , Virtual, 2020)
TriMAD Conference 2023 Pennsylvania US + (10th Translational Research in Mitochondri … 10th Translational Research in Mitochondria/Metabolism, Aging, and Disease (TRiMAD) Conference, Pennsylvania, United States, 2023 == General information ==:::: TRiMAD is a collaborative venture between The Pennsylvania State University, University of Pittsburgh Medical Center, The Children’s Hospital of Philadelphia (CHoP) Research Institute, and The University of Pennsylvania Perelman School of Medicine ([https://www.huck.psu.edu/node/15830 Website])== Venue == :::: University of Pittsburgh:::: Bridgeside Point 1, 5th Floor:::: 100 Technology Drive:::: Pittsburgh, PA 15219== Organizers ==:::: University of Pittsburgh:::: Aging Institute:::: Center for Metabolism & Mitochondrial Medicine== Program ==:::: Please find the programme [https://aging.pitt.edu/event/trimad-2023/ here]== Registration ==:::: [https://forms.office.com/pages/responsepage.aspx?id=ifT5nqDg606HzDpSYRL9DXg8U8hQ84RKssucFsBERrBURTU2T1lFR01DS0hYNlZGRjNDTzg2QVJRSC4u Register here] == Lecturers and tutors ==:::: The list of speakers can be found [https://aging.pitt.edu/event/trimad-2023/ here]ttps://aging.pitt.edu/event/trimad-2023/ here])
Targeting Mitochondria World Congress 2019 Berlin DE + (10th World Congress on Targeting Mitochond … 10th World Congress on Targeting Mitochondria, Berlin, Germany, 2019 == General information == :::: Flyer available for [http://wiki.oroboros.at/images/7/7f/Berlin_2019.pdf download]== Venue == :::: INTERCONINENTAL BERLIN HOTEL:::: Budapester Str. 2, 10787:::: Berlin, Germany::::[https://targeting-mitochondria.com/venue Hotel and Travel]== Programme ==:::: [https://targeting-mitochondria.com/preliminary-program here]== Speakers == :::: List of speakers can be found [https://targeting-mitochondria.com/speakers-2019 here]== Registration ==:::: [https://targeting-mitochondria.com/registration Registration and more information]tration Registration and more information])
115th International Titisee Conferences Titisee DE + (115th ITC: Evolutionary mitochondrial biology: molecular, biochemical, and metabolic diversity, Titisee, Germany.)
11th Annual Congress of Cardiology 2019 Suzhou CN + (11th Annual Congress of Cardiology, Suzhou, China, 2019)
MiP2015 + (11th Conference on Mitochondrial Physiology, 2015 Sep 07-11, Luční Bouda, Czech Republic.)
Targeting Mitochondria World Congress 2020 Virtual + (11th World Congress on Targeting Mitochond … 11th World Congress on Targeting Mitochondria, Virtual, 2020 == General information == :::: After a long and thorough discussion among the scientific and organizing committees, we have decided to organize our 11th Conference of Targeting Mitochondria, on October 29-30, 2020 as an ONLY Virtual Congress.== Programme ==:::: [https://targeting-mitochondria.com/preliminary-program here]== Speakers == :::: List of speakers can be found [https://targeting-mitochondria.com/speakers here]== Registration ==:::: [https://targeting-mitochondria.com/registration Registration and more information]tration Registration and more information])
11th ÖGMBT Annual Meeting 2019 Salzburg AT + (11th ÖGMBT Annual Meeting - Inside the world of biomolecules, Salzburg, Austria, 2019)
ASMRM 2015 Hangzhou CN + (12th Conference of the Asian Society of Mitochondrial Research and Medicine - [http://www.ig.zju.edu.cn/ASMRM/EN/ ASMRM 2015], Hangzhou CN)
12th International Conference on Obesity and Eating Disorders 2023 Vienna AT + (12th International Conference on Obesity a … 12th International Conference on Obesity and Eating Disorders, Vienna, Austria, 2023 == General Information == :::: The theme of the conference is "New Emerging Challenges in Obesity and their Prevention"== Venue ==:::: [https://obesity.euroscicon.com/ How to get there]== Program ==:::: Program available [https://obesity.euroscicon.com/program-schedule here]== Organizers ==:::: The list of organizers can be found [https://obesity.euroscicon.com/organizing-committee here]== Registration ==:::: [https://obesity.euroscicon.com/registration Registration and more information]:::: Early registration deadline: 203-01-27:::: Late registration deadline: 2023-04-10::: Late registration deadline: 2023-04-10)
IPC2021 Puerto Varas CL + (12th International Phycological Congress - … 12th International Phycological Congress - IPC2021, Puerte Varas, Chile, 2021 == Venue == ::::[https://ipc2021.com/logistic-information/ Venue and how to get there]== Programme ==:::: [https://ipc2021.com/scientific-program/ here]== Speakers == :::: List of speakers can be found [https://ipc2021.com/invited-speakers/ here]== Organizers ==:::: The list of organizers can be found [https://ipc2021.com/local-organizing-committee-scientific-committee/ here]== Registration ==:::: [https://ipc2021.com/registration-and-registration-fees-submission-of-abstracts/ Registration and more information]tracts/ Registration and more information])
12th ÖGMBT Annual Meeting 2020 Virtual Event + (12th ÖGMBT Annual Meeting - Biomolecules in/for 21st century, Virtual Event, 2020 '''''- Conference will be held via a virtual interactive meeting. Oroboros Instruments will be present with a virtual booth.''''')
Life Sciences Meeting 2018 Innsbruck AT + (13th Life Sciences Meeting, Innsbruck, Aus … 13th Life Sciences Meeting, Innsbruck, Austria, 2018 __TOC__== General information== :::: The coming meeting will take place on the 5th and 6th of April, 2018 in the CCB (Center for Chemistry and Biomedicine) and offers all participants and young researchers the possibility to present their research work in the form of a posters or a short talk. At the end of the event the best presentation will be selected by a professional jury consisting of professors of the Medical University of Innsbruck and the winners will be awarded with a prize. The closure of the meeting will be made by the famous scientist Prof. Jannie Cracking of the Netherland Cancer Institute. The Medical University of Innsbruck is looking forward to welcoming Prof. Cracking as a „Key Note Speaker“. == Venue == :::: Center for Chemistry and Biomedicine (CCB):::: Innrain 80, 6020 Innsbruck:::: [http://biocenter.i-med.ac.at/ Location]== Organizers ==:::: Medical University of Innsbruck==Oroboros presentation ==:::: TALK: Marie Skłodowska-Curie Project '''[[TRANSMIT]]''' [[Bastos Sant'Anna Silva AC|Bastos Sant'Anna Silva Ana Carolina]]: [[Bastos Sant'Anna Silva AC 2018 Life Sciences Meeting 2018 Innsbruck AT|Effect of cell-permeable succinate and malonate prodrugs on mitochondrial respiration in prostate cancer cells]]:::: POSTER: Marie Skłodowska-Curie Project '''[[TRACT]]''' [[Chang Shao-Chiang]]: [[Chang 2018 Life Sciences Meeting 2018 Innsbruck AT|pH dependence of mitochondrial respiration and H2O2 production in oral cancer cells – a pilot study.]]:::: POSTER: K-Regio Project '''[[K-Regio_MitoFit|MitoFit]]''' [[Garcia-Souza LF|Garcia-Souza Luiz]]: [[Garcia-Souza 2018 Life Sciences Meeting 2018 Innsbruck AT|A respirometric cell viability test for peripheral-blood mononuclear cells and platelets]]-Souza 2018 Life Sciences Meeting 2018 Innsbruck AT|A respirometric cell viability test for peripheral-blood mononuclear cells and platelets]])
13th Targeting Mitochondria Congress 2022 Berlin DE + (13th Targeting Mitochondria Congress, Berlin, 2022)
EBSA2021 Vienna AT + (13th congress of EBSA, Vienna, Austria, 2021)
13th ÖGMBT Annual Meeting 2021 Innsbruck AT + (13th ÖGMBT Annual Meeting, Virtual, 2021)
FAOBMB 2015 Hyderabad IN + (14th Congress of the Federation of Asian and Oceanian Biochemists and Molecular Biologists (FAOBMB) - [http://www.ccmb.res.in/faobmb2015/ FAOBMB 2015], Hyderabad IN)
EBSA 2023 Stockholm SE + (14th congress of EBSA, Stockholm, Sweden, 2023)
The Power of Metabolism Linking energy supply and demand with contractile function 2017 Weimar DE + (15th Annual Meeting: The Power of Metabolism - Linking energy supply and demand with contractile function, Weimar,)
ASMRM 2018 Busan KR + (15th Conference of the Asian Society of Mitochondrial Research and Medicine, Busan, South Korea, 2018.)
16th Chinese Biophysics Congress 2018 Chengdu CH + (16th Chinese Biophysics Congress - Biophysics and human health , Chengdu, China, 2018)
J-mit 2017 Kyoto JP + (17th Annual Conference of Janpanese Society of Mitochondrial Research and Medicine, Kyoto, Japan)

17th Chinese Biophysics Congress 2019 Tianjin CN + (17th Chinese Biophysics Congress, Tianjin , China, 2019)

17th International Biochemistry of Exercise Conference 2018 Beijing CN + (17th International Biochemistry of Exercise Conference, Beijing, China, 2018)
The 18th Annual Meeting of the Japan Mitochondrial Association 2018 Kurume JP + (18th Annual Meeting of the Japan Mitochondrial Association, Kurume, 2018)
KSMRM2014 + (19th Annual Scientific Meeting of KSMRM , Seoul, Republic of Korea; [http://2014.ksmrm.org/congress/invitation.php KSMRM2014])
SHVM 2022 Seoul KR + (19th Annual Meeting of the Society for Heart and Vascular Metabolism (SHVM), Seoul , South Korea, 2022)
19th Beijing Conference and Exhibition on Instrumental Analysis 2021 Beijing CN + (19th Beijing Conference and Exhibition on Instrumental Analysis, Beijing, China, 2021)
19th Chinese Biophysics congress 2021 Anhui CN + (19th Chinese Biophysics congress, Anhui Province, China, 2021)
ESP2021 Salzburg AT + (19th Congress of the European Society for … 19th Congress of the European Society for Photobiology - ESP2021, Salzburg, Austria, 2021 == Venue == :::: Faculty of Natural Sciences (NAWI) of the Paris Lodron University Salzburg (PLUS):::: Venue address: Hellbrunnerstrasse 34, 5020 Salzburg, Austria.:::: [http://salzburg2021.photobiology.eu/congress-venue more information]== Program ==:::: [http://salzburg2021.photobiology.eu/ here]== Speakers == :::: List of speakers can be found [http://salzburg2021.photobiology.eu/ here]== Organizers ==:::: The list of organizers can be found [http://salzburg2021.photobiology.eu/organizing-committee here]== Registration ==:::: [http://salzburg2021.photobiology.eu/ Registration and more information]ogy.eu/ Registration and more information])
Chlamy 2021 Ile des Embiez FR + (19th International Conference on the Cell and Molecular Biology of Chlamydomonas, Ile des Embiez, France, 2021)
FEBS 2023 Luso PT + (1st 1st FEBS Workshop “Redox Medicine Workshop, Luso, Portugal, 2023)
MiPschool Schroecken AT 2007 + (1st MiP''summer school'' on Mitochondrial Respiratory Physiology, 2007 July 12-18, Schroecken, AT.)
1st Myocardial Function Symposium 2020 Graz AT + (1st Myocardial Function Symposium: “Targets in cardiometabolic disease”, Graz, Austria, 2020)
SHVM 2021 Virtual + (1st virtual meeting of the Society for Heart and Vascular Metabolism (SHVM), Virtual, 2021)
Goncalves 2017 J Cell Commun Signal + (1α,25-Dihydroxyvitamin D3</s … 1α,25-Dihydroxyvitamin D3 (1,25-D3) is critical for the maintenance of normal male reproduction since reduced fertility is observed in vitamin D-deficient rats. Gamma-glutamyl transpeptidase (GGT) is a membrane-bound enzyme that is localized on Sertoli cells and catalyses the transfer of the gamma-glutamyl residues to an amino acid or peptide acceptor. Sertoli cells are also responsible for providing nutrients, as lactate, to the development of germ cells. The aim of this study was to investigate the effect and the mechanism of action of 1,25-D3 on GGT on Sertoli cell functions from 30-day-old immature rat testis. Results demonstrated that 1,25-D3 stimulates GGT activity at Sertoli cells plasma membrane through a PKA-dependent mechanism of action, which was not dependent of active ''de novo'' protein synthesis. The hormone increases glucose uptake, as well as lactate production and release by Sertoli cells without altering the reactive oxygen species (ROS) generation. In addition, 1,25-D3 did not change reduced glutathione (GSH) amount or oxygen consumption, and diminished Sertoli cell death. These findings demonstrate that 1,25-D3 stimulatory effect on GGT activity, glucose uptake, LDH activity and lactate production seem to be an important contribution of Sertoli cells for germ cells nutrition and for a full and active ongoing spermatogenesis.mportant contribution of Sertoli cells for germ cells nutrition and for a full and active ongoing spermatogenesis.)
Royall 1993 Arch Biochem Biophys + (2',7'-Dichlorofluorescein and dihydrorhoda … 2',7'-Dichlorofluorescein and dihydrorhodamine 123 were evaluated as probes for detecting changes in intracellular H2O2 in cultured endothelial cells. Stable intracellular levels of these probes were established within 15 min of exposure to the probe in culture medium. With continued presence of the probe in the medium, intracellular levels were unchanged for 1 h. However, if medium without the probes was used after intracellular loading had occurred, there was a greater than 90% loss of intracellular dichlorofluorescin, dichlorofluorescein, and dihydrorhodamine 123 while intracellular rhodamine 123 decreased by only 15%. Exposure of endothelial cells to exogenous 100 microM H2O2 for 1 h increased intracellular rhodamine 123 by 83%, but there was a reproducible decrease of 53% in intracellular dichlorofluorescein. Exposure to 0.05 mM BCNU plus 10 mM aminotriazole for 2 h increased intracellular rhodamine 123 by 111%. In vitro studies of dihydrorhodamine 123 oxidation were similar to previous reports of dichlorofluorescin oxidation. Oxidation of dihydrorhodamine 123 does not occur with H2O2 alone, but is mediated by a variety of secondary H2O2-dependent intracellular reactions including H2O2-cytochrome c and H2O2-Fe2+. Our results suggest that detection of increased oxidation of these probes in endothelial cells is most useful as a marker of a change in general cellular oxidant production.ge in general cellular oxidant production.)
Lardy 1953 J Biol Chem + (2,4-Dinitrophenol greatly enhanced the … 2,4-Dinitrophenol greatly enhanced the liberation of inorganic phosphate from ATP by the nuclear and mitochondrial fraction of rat liver. The microsomal and supernatant fractions did not exhibit this effect. With mitochondria (Mw) the rate of phosphate liberation was proportional to the DNP concentration up to 6 X 10-5 M In the presence of excess DNP the rate was proportional to the quantity of Mw nd to time. With both fresh and preaged Mw, the response to DNP was much greater in mediums containing salt (either NaCl or KCl) than in isotonic sucrose. Magnesium salts in appreciable concentrations depressed the response of fresh Mw to DNP, but enhanced the response in preaged Mw. Calcium salts, which activate ATP hydrolysis by fresh Mw in the absence of DNP, also depressed the effect of DNP on phosphate liberation. Magnesium salts enhanced phosphate liberation by preaged Mw both in the presence and absence of DNP. Calcium was virtually without effect in preaged Mw. Oxalacetate enhanced phosphate liberation from ATP by fresh Mw. This dicarboxylic acid as well as succinate and L-malate depressed the effect of DNP on phosphate liberation. Fatty acids also depressed the effect of DNP. Caprylate enhanced phosphate liberation, probably be- cause of its surface activity. The thiol inhibitor, p-chloromercuribenzoate, strongly depressed the effect of DNP; iodoacetate and o-iodosobenzoate did not.''Continued in Free Text''ate did not. ''Continued in Free Text'')
Freitas-Correa 2013 Stem Cell Res + (2,4-Dinitrophenol (DNP) is a neuroprotecti … 2,4-Dinitrophenol (DNP) is a neuroprotective compound previously shown to promote neuronal differentiation in a neuroblastoma cell line and neurite outgrowth in primary neurons. Here, we tested the hypothesis that DNP could induce neurogenesis in embryonic stem cells (ESCs). Murine ESCs, grown as embryoid bodies (EBs), were exposed to 20μM DNP (or vehicle) for 4days. Significant increases in the proportion of nestin- and β-tubulin III-positive cells were detected after EB exposure to DNP, accompanied by enhanced glial fibrillary acidic protein (GFAP), phosphorylated extracellular signal-regulated kinase (p-ERK) and ATP-linked oxygen consumption, thought to mediate DNP-induced neural differentiation. DNP further protected ESCs from cell death, as indicated by reduced caspase-3 positive cells, and increased proliferation. Cell migration from EBs was significantly higher in DNP-treated EBs, and migrating cells were positive for nestin, ß-tubulin III and MAP2, similar to that observed with retinoic acid (RA)-treated EBs. Compared to RA, however, DNP exerted a marked neuritogenic effect on differentiating ESCs, increasing the average length and number of neurites per cell. Results establish that DNP induces neural differentiation of ESCs, accompanied by cell proliferation, migration and neuritogenesis, suggesting that DNP may be a novel tool to induce neurogenesis in embryonic stem cells.duce neurogenesis in embryonic stem cells.)
Sebollela 2010 Neurotox Res + (2,4-Dinitrophenol (DNP) is classically kno … 2,4-Dinitrophenol (DNP) is classically known as a mitochondrial uncoupler and, at high concentrations, is toxic to a variety of cells. However, it has recently been shown that, at subtoxic concentrations, DNP protects neurons against a variety of insults and promotes neuronal differentiation and neuritogenesis. The molecular and cellular mechanisms underlying the beneficial neuroactive properties of DNP are still largely unknown. We have now used DNA microarray analysis to investigate changes in gene expression in rat hippocampal neurons in culture treated with low micromolar concentrations of DNP. Under conditions that did not affect neuronal viability, high-energy phosphate levels or mitochondrial oxygen consumption, DNP induced up-regulation of 275 genes and down-regulation of 231 genes. Significantly, several up-regulated genes were linked to intracellular cAMP signaling, known to be involved in neurite outgrowth, synaptic plasticity, and neuronal survival. Differential expression of specific genes was validated by quantitative RT-PCR using independent samples. Results shed light on molecular mechanisms underlying neuroprotection by DNP and point to possible targets for development of novel therapeutics for neurodegenerative disorders.rapeutics for neurodegenerative disorders.)
2014 Mitochondrial Disease Clinical Conference + (2014 Mitochondrial Disease Clinical Conference, Los Angeles, Ca US; [http://www.mitoaction.org/laconference 2014 Mitochondrial Disease Clinical Conference])
2015 Spring PaduaMuscleDays + (2015 Spring PaduaMuscleDays: Translational Myology in Aging and Neuromuscular Disorders, Padova, IT; [http://www.pagepressjournals.org/index.php/bam/announcement/view/176 2015 Spring PaduaMuscleDays].)
2016 Spring PaduaMuscleDays Padua IT + (2016 Spring PaduaMuscleDays: Muscle Decline in Aging and Neuromuscular Disorders - Mechanisms and Countermeasures, Padua, IT)
JSBBA 2017 Kyoto JP + (2017 Annual Meeting of the Japan Society for Bioscience, Biotechnology, and Agrochemistry (JSBBA), Kyoto, Japan)
Movement and Cognition 2018 MA US + (2018 world conference on Movement and Cognition, Boston, Massachusetts, USA, 2018)
Movement and Cognition 2019 Tel-Aviv IL + (2019 World conference on Movement and Cognition, Tel-Aviv, Israel, 2019)
2020 PaduaMuscleDays Padua IT + (2020 PaduaMuscleDays - 30 years of translational research, Vitual Event, 2020)
Movement and Cognition 2020 Paris FR + (2020 World conference on Movement and Cognition, Paris, France, 2020)
EBEC2018 Budapest HU + (20th European Bioenergetics Conference 2018, Budapest, Hungary, 2018)
SHVM 2023 Graz AT + (20th Annual Meeting of the Society for Heart and Vascular Metabolism (SHVM), Graz, Austria, 2023)
SFRR 2021 Virtual + (20th Biennial Meeting of SFRR International, Virtual, 2021)
International Botanical Congress 2024 Madrid ES + (20th International Botanical Congress (IBC), Madrid, ES, 2024)
EBEC2022 Aix-en-Provence FR + (21st European Bioenergetics Conference 2022, Aix-en-Provence, France, 2022.)
EBEC2024 Innsbruck AT + (22st European Bioenergetics Conference 2024, Innsbruck, Austria, 2024)
GFB 2023 Bedoin FR + (22nd GFB conference, Bedoin, France, 2023)
24th Kalorimetrietage 2021 Braunschweig DE + (24th Kalorimetrietage, Braunschweig, Germany, 2021.)
25th Krakow Conference on Endothelium 2017 PL + (25th Krakow Conference on Endothelium, Krakow, Poland.)
SFRR 2018 Auckland NZ + (26th Meeting for the Society for Free Radical Research Australasia SFRR(A), Auckland, New Zeland, 2018)
ECSS 2023 Paris FR + (28th ECSS Congress, Paris, France, 2023)
28th Congress of the Polish Physiological Society 2021 Virtual + (28th Congress of the Polish Physiological Society, Virtual, 2021)
FEBS 2022 Mutters AT + (2nd FEBS Workshop on Ageing and Regeneration, Mutters, Austria, 2022)
Cardiovascular Metabolic Disease 2015 + (2nd Annual Conference of the Prevention and Control of Cardiovascular Metabolic Disease, Wuhan, CN; post-conference workshop '''[[MiPNet20.11_IOC102_Wuhan | 102nd Oroboros O2k-Workshop]]'''.)
Mitochondria-Targeted Drug Development 2022 Boston US + (2nd Annual Mitochondria-Targeted Drug Development, Boston MA, US, 2022.)
2nd International Munich ROS Meeting 2018 Munich DE + (2nd International Munich ROS Meeting, Munich, Germany, 2018)
2nd Mitochondria Conference 2023 Lisbon PT + (2nd Mitochondria Conference, Lisbon, Portugal, 2023.)
Pereira 2009 Biochem J + (3-BrPA (3-bromopyruvate) is an alkylating … 3-BrPA (3-bromopyruvate) is an alkylating agent with antitumoral activity on hepatocellular carcinoma. This compound inhibits cellular ATP production owing to its action on glycolysis and oxidative phosphorylation; however, the specific metabolic steps and mechanisms of 3-BrPA action in human hepatocellularcarcinomas, particularly its effects on mitochondrial energetics, are poorly understood. In the present study it was found that incubation of HepG2 cells with a low concentration of 3-BrPA for a short period (150 μMfor 30 min) significantly affected both glycolysis and mitochondrial respiratory functions. The activity of mitochondrial hexokinase was not inhibited by 150 μM 3-BrPA, but this concentration caused more than 70% inhibition of GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and 3-phosphoglycerate kinase activities. Additionally, 3-BrPA treatment significantly impaired lactate production by HepG2 cells, even when glucose was withdrawn from the incubation medium.Oxygen consumption of HepG2 cells supported by either pyruvate/malate or succinate was inhibited when cells were preincubated with 3-BrPA in glucose-free medium. On the other hand, when cells were pre-incubated in glucose-supplemented medium, oxygen consumption was affected only when succinatewas used as the oxidizable substrate. An increase in oligomycinindependentrespiration was observed in HepG2 cells treated with 3-BrPA only when incubated in glucose-supplemented medium, indicating that 3-BrPA induces mitochondrial proton leakage as well as blocking the electron transport system. The activityof succinate dehydrogenase was inhibited by 70% by 3-BrPA treatment. These results suggest that the combined action of 3- BrPA on succinate dehydrogenase and on glycolysis, inhibiting steps downstream of the phosphorylation of glucose, play an important role in HepG2 cell death.lay an important role in HepG2 cell death.)
Jardim-Messeder 2012 Int J Biochem Cell Biol + (3-Bromopyruvate (3BrPA) is an antitumor ag … 3-Bromopyruvate (3BrPA) is an antitumor agent that alkylates the thiol groups of enzymes and has been proposed as a treatment for neoplasias because of its specific reactivity with metabolic energy transducing enzymes in tumor cells. In this study, we show that the sarco/endoplasmic reticulum calcium (Ca2+) ATPase (SERCA) type 1 is one of the target enzymes of 3BrPA activity. Sarco/endoplasmic reticulum vesicles (SRV) were incubated in the presence of 1mM 3BrPA, which was unable to inhibit the ATPase activity of SERCA. However, Ca2+-uptake activity was significantly inhibited by 80% with 150μM 3BrPA. These results indicate that 3BrPA has the ability to uncouple the ATP hydrolysis from the calcium transport activities. In addition, we observed that the inclusion of 2mM reduced glutathione (GSH) in the reaction medium with different 3BrPA concentrations promoted an increase in 40% in ATPase activity and protects the inhibition promoted by 3BrPA in calcium uptake activity. This derivatization is accompanied by a decrease of reduced cysteine (Cys), suggesting that GSH and 3BrPA increases SERCA activity and transport by pyruvylation and/or S-glutathiolation mediated by GSH at a critical Cys residues of the SERCA.hiolation mediated by GSH at a critical Cys residues of the SERCA.)
Jardim-Messeder 2016 Anticancer Res + (3-bromopyruvate (3BrPA) is an antitumor ag … 3-bromopyruvate (3BrPA) is an antitumor agent able to inhibit aerobic glycolysis and oxidative phosphorylation, therefore inducing cell death. However, cancer cells are also highly dependent of glutaminolysis and tricarboxylic acid cycle (TCA) regarding survival and 3BrPA action in these metabolic routes is poorly understood.The effect of 3BrPA was characterized in mice liver and kidney mitochondria, as well as in human HepG2 cells.Low concentration of 3-BrPA significantly affected both glutaminolysis and TCA cycle functions, through inhibition of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase and succinate dehydrogenase. Additionally, 3-BrPA treatment significantly decreased the reduced status of thiol groups in HepG2 cells without proportional increase of oxidizing groups, suggesting that these chemical groups are the target of alkylation reactions induced by 3-BrPA.This work demonstrates, for the first time, the effect of 3-BrPA in glutaminolysis and TCA cycle. Our results suggest that the combined action of 3-BrPA in glutaminolysis, TCA and glycolysis, inhibiting steps downstream of the glucose and glutamine metabolism, has an antitumor effect.Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.John G. Delinassios), All rights reserved.)
Vevera 2016 Physiol Res + (3-hydroxy-3-methylglutaryl-coenzyme A (HMG … 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used drugs for lowering blood lipid levels and preventing cardiovascular diseases. However, statins can have serious adverse effects, which may be related to development of mitochondrial dysfunctions. The aim of study was to demonstrate the ''in vivo'' effect of high and therapeutic doses of statins on mitochondrial respiration in blood platelets. Model approach was used model in the study. Simvastatin was administered to rats at a high dose for 4 weeks. Humans were treated with therapeutic doses of rosuvastatin or atorvastatin for 6 weeks. Platelet mitochondrial respiration was measured using high-resolution respirometry. In rats, a significantly lower physiological respiratory rate was found in intact platelets of simvastatin-treated rats compared to controls. In humans, no significant changes in mitochondrial respiration were detected in intact platelets; however, decreased complex I-linked respiration was observed after statin treatment in permeabilized platelets. We propose that the small ''in vivo'' effect of statins on platelet energy metabolism can be attributed to drug effects on complex I of the electron transport system. Both intact and permeabilized platelets can be used as a readily available biological model to study changes in cellular energy metabolism in patients treated with statins.tabolism in patients treated with statins.)
JACBS Taipei TW + (32th Joint Annual Conference of Biomedical Science, Taipei, Taiwan.)
APS2020 Chicago US + (32nd APS Annual Convention, Chicago, USA, 2020)
36th Congress Czech Nutrition Society 2020 Hradec Kralove CZ + (36th annual international congress of Czech Nutrition Society, Hradec Kralove, Czech Republic, 2020)
37th Annual Meeting of the ISHR-ES 2023 Porto PT + (37th Annual Meeting of the ISHR-ES, Porto, Portugal, 2023)
MiPschool Baton Rouge LA US 2009 + (3rd MiP''summer school'' on Mitochondrial Respiratory Physiology, 2009 June 17-23, Baton Rouge, Louisiana US.)
Eugeny I. Schwartz Conference 2015 + (3rd Russian Congress with International Participation “Molecular Basis of Clinical Medicine: State-of-the-Art and Perspectives” dedicated to the memory of Eugeny I. Schwartz, St. Petersburg , Russia;)
Ophthalmology Conference 2018 Rome IT + (3rd Edition of International Conference on Eye and Vision, Rome, Italy; 2018)
METABO & Cancer 2019 Marseille FR + (3rd edition - Metabolism and Cancer Meeting, Marseille, France, 2019)
MacDonald 2014 Abstract MiP2014 + (4-hydroxy-2-oxoglutarate aldolase (HOGA) i … 4-hydroxy-2-oxoglutarate aldolase (HOGA) is a bi-functional mitochondrial enzyme, expressed predominantly in liver and kidney. HOGA is involved in the hydroxyproline degradation pathway (HOGglyoxylate+pyruvate), and mutations in HOGA result in primary Hyperoxaluria Type III, characterized by excessive oxalate production and kidney stone deposition [1]. We hypothesized that HOGA may also be involved in the TCA cycle as an oxaloacetate decarboxylase (oxaloacetatepyruvate; Fig. 1), which may allow the TCA cycle to turnover in the absence of pyruvate and/or excess oxaloacetate. The kinetics of HOGA with substrates HOG and oxaloacetate were investigated by measuring the ''K''’m and ''k''cat of recombinant human HOGA, using an LDH-coupled microplate assay. The role of HOGA in the TCA cycle was investigated using mitochondria, isolated from rat liver and kidney, where HOGA is highly expressed, and brain and heart, where expression is lower. ADP-stimulated malate respiration was measured relative to ADP-malate + pyruvate (M:PM), using oxygraphy (Oroboros Oxygraph-2k, note malate was used as oxaloacetate cannot cross the inner mitochondrial membrane). While HOGA was 75% less efficient at cleaving oxaloacetate than its other substrate, HOG (''K''’m/''k''cat), the ''K''’m for oxaloacetate was within range of that estimated for TCA intermediates (''K''’m,ox=129±8 µM, ''k''cat,ox=0.52±0.01 s-1; ''K''’m,HOG=55±5 µM, ''k''cat,HOG=1.01±0.03 s-1). Overall, HOGA appears to use the same catalytic mechanism to cleave both HOG and oxaloacetate substrates. Interestingly, the TCA cycle intermediate a-ketoglutarate was found to be a competitive inhibitor of HOGA oxaloacetate decarboxylase activity (''K''i=2.8 mM). Mitochondria from rat liver had the highest M:PM respiration relative to all other organs (0.46±0.05, ''P''<0.05). Though kidney had a higher M:PM respiration than heart (0.27±0.02 vs 0.15±0.02, ''P''<0.05 in kidney and heart, respectively), brain respired as well as kidney (0.33±0.04). In summary, HOGA cleaves oxaloacetate and HOG using the same catalytic mechanism but was less efficient with oxaloacetate. Liver and kidney have high HOGA expression, and mitochondria from both respire significantly better on malate relative to PM than heart mitochondria. The brain respires just as well with malate compared to kidney, and this may be due to high expression of malic enzyme, which can convert malate directly to pyruvate (Fig. 1). Malate supported respiration in HOGA overexpressing cells will confirm the direct role of HOGA in the TCA cycle.ession of malic enzyme, which can convert malate directly to pyruvate (Fig. 1). Malate supported respiration in HOGA overexpressing cells will confirm the direct role of HOGA in the TCA cycle.)
MBSJ 2018 Yokohama JP + (41st Annual Meeting of the Molecular Biology Society of Japan, Yokohama, Japan, 2018.)
The 42nd Annual Meeting of The Molecular Biology Society of Japan + (42nd Annual Meeting of The Molecular Biology Society of Japan, Kurume, 2018)
ISOTT 2015 + (43rd Annual Meeting of the International Society on Oxygen Transport to Tissue (ISOTT))
AICBC 2024 Navi Mumbai IN + (46th All India Cell Biology Conference, Navi Mumbai, India, 2024)
46th ISOBM Congress 2019 Athens GR + (46th annual congres of the International Society of Oncology and Biomarkers, Athens, Greece, 2019)
ESCI 2015 + (49th Annual Scientific Meeting of the European Society for Clinical Investigation, Cluj-Napoca, Romania; [http://www.esci.eu.com/meetings/ ESCI 2015])
SMRM2014 Manipal IN + (4th Annual Conference of the Society for Mitochondrial Research and Medicine, Kolkata, India.)
MiPschool Druskininkai LT 2010 + (4th MiP''summer school'' on Mitochondrial Respiratory Physiology, 2010 June 10-16, Druskininkai, Lithuania.)
TrMAD2014 + (4th Regional Translational Research in Mitochondria, Aging, and Disease Symposium, Pittsburgh, PA, US. [http://www.upci.upmc.edu/trmad/ TrMAD2014])
4th Global Chinese Symposium & The 8th Symposium for Cross-straits on Free Radical Biology and Medicine 2018 Macao CN + (4th Global Chinese Symposium & The 8th Symposium for Cross-straits, Hong Kong and Macao on Free Radical Biology and Medicine, Macao, China, 2018)
4th edition Metabolism & Cancer 2021 Virtual + (4th edition Metabolism & Cancer, Virtu … 4th edition Metabolism & Cancer, Virtual, 2021 == Program ==:::: [https://www.metabolism-cancer.com/program/ here]== Organizers ==:::: The list of organizers can be found [https://www.metabolism-cancer.com/under-construction/ here]== Registration ==:::: [https://www.metabolism-cancer.com/registration/ Registration and more information]== Oroboros at MetaboCancer 2021==:::: [[Gnaiger Erich]]: Oroboros Instruments innovations - NextGen-O2k and Bioenergetics Communications, ''May 28th at 11:25''=== Booth ===:::: The Oroboros team is looking forward to welcome you at our Oroboros booth which will be available at this conference.== Support ==[[File:Template NextGen-O2k.jpg|right|350px|link=NextGen-O2k]][[Category:NextGen-O2k]]:::: Supported by project NextGen-O2k which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 859770. agreement No. 859770. )
MacPherson 2016 Am J Physiol Cell Physiol + (5'-AMP-activated protein kinase (AMPK) is … 5'-AMP-activated protein kinase (AMPK) is activated as a consequence of lipolysis and has been shown to play a role in regulation of adipose tissue mitochondrial content. Conversely, the inhibition of lipolysis has been reported to potentiate the induction of protein kinase A (PKA)-targeted genes involved in the regulation of oxidative metabolism. The purpose of the current study was to address these apparent discrepancies and to more fully examine the relationship between lipolysis, AMPK, and the β-adrenergic-mediated regulation of gene expression. In 3T3-L1 adipocytes, the adipose tissue triglyceride lipase (ATGL) inhibitor ATGListatin attenuated the Thr(172) phosphorylation of AMPK by a β3-adrenergic agonist (CL 316,243) independent of changes in PKA signaling. Similarly, CL 316,243-induced increases in the Thr(172) phosphorylation of AMPK were reduced in adipose tissue from whole body ATGL-deficient mice. Despite reductions in the activation of AMPK, the induction of PKA-targeted genes was intact or, in some cases, increased. Similarly, markers of mitochondrial content and respiration were increased in adipose tissue from ATGL knockout mice independent of changes in the Thr(172) phosphorylation of AMPK. Taken together, our data provide evidence that AMPK is not required for the regulation of adipose tissue oxidative capacity in conditions of reduced fatty acid release.Copyright © 2016 the American Physiological Society.© 2016 the American Physiological Society.)
Stride 2012 Front Physiol + (5'-adenosine monophosphate-activated prote … 5'-adenosine monophosphate-activated protein kinase (AMPK) is considered central in regulation of energy status and substrate utilization within cells. In heart failure the energetic state is compromised and substrate metabolism is altered. We hypothesized that this could be linked to changes in AMPK activity and we therefore investigated mitochondrial oxidative phosphorylation capacity from the oxidation of long- and medium-chain fatty acids (LCFA and MCFA) in cardiomyocytes from young and old mice expressing a dominant negative AMPKα2 (AMPKα2-KD) construct and their wildtype (WT) littermates. We found a 35-45% (P < 0.05) lower mitochondrial capacity for oxidizing MCFA in AMPKα2-KD of both age-groups, compared to WT. This coincided with marked decreases in protein expression (19/29%, P < 0.05) and activity (14/21%, P < 0.05) of 3-hydroxyacyl-CoA-dehydrogenase (HAD), in young and old AMPKα2-KD mice, respectively, compared to WT. Maximal LCFA oxidation capacity was similar in AMPKα2-KD and WT mice independently of age implying that LCFA-transport into the mitochondria was unaffected by loss of AMPK activity or progressing age. Expression of regulatory proteins of glycolysis and glycogen breakdown showed equivocal effects of age and genotype. These results illustrate that AMPK is necessary for normal mitochondrial function in the heart and that decreased AMPK activity may lead to an altered energetic state as a consequence of reduced capacity to oxidize MCFA. We did not identify any clear aging effects on mitochondrial function. any clear aging effects on mitochondrial function.)
Hanley 2005 J Physiol + (5-Hydroxydecanoate (5-HD) blocks pharmacol … 5-Hydroxydecanoate (5-HD) blocks pharmacological and ischaemic preconditioning, and has been postulated to be a specific inhibitor of mitochondrial ATP-sensitive K+ (KATP) channels. However, recent work has shown that 5-HD is activated to 5-hydroxydecanoyl-CoA (5-HD-CoA), which is a substrate for the first step of β-oxidation. We have now analysed the complete β-oxidation of 5-HD-CoA using specially synthesised (and purified) substrates and enzymes, as well as isolated rat liver and heart mitochondria, and compared it with the metabolism of the physiological substrate decanoyl-CoA. At the second step of β-oxidation, catalysed by enoyl-CoA hydratase, enzyme kinetics were similar using either decenoyl-CoA or 5-hydroxydecenoyl-CoA as substrate. The last two steps were investigated using l-3-hydroxyacyl-CoA dehydrogenase (HAD) coupled to 3-ketoacyl-CoA thiolase. ''V''max for the metabolite of 5-HD (3,5-dihydroxydecanoyl-CoA) was fivefold slower than for the corresponding metabolite of decanoate (l-3-hydroxydecanoyl-CoA). The slower kinetics were not due to accumulation of d-3-hydroxyoctanoyl-CoA since this enantiomer did not inhibit HAD. Molecular modelling of HAD complexed with 3,5-dihydroxydecanoyl-CoA suggested that the 5-hydroxyl group could decrease HAD turnover rate by interacting with critical side chains. Consistent with the kinetic data, 5-hydroxydecanoyl-CoA alone acted as a weak substrate in isolated mitochondria, whereas addition of 100 μm 5-HD-CoA inhibited the metabolism of decanoyl-CoA or lauryl-carnitine. In conclusion, 5-HD is activated, transported into mitochondria and metabolised via β-oxidation, albeit with rate-limiting kinetics at the penultimate step. This creates a bottleneck for β-oxidation of fatty acids. The complex metabolic effects of 5-HD invalidate the use of 5-HD as a blocker of mitochondrial KATP channels in studies of preconditioning.TP channels in studies of preconditioning.)
Mitchell 2011 Biochim Biophys Acta + (50 years ago Peter Mitchell proposed the c … 50 years ago Peter Mitchell proposed the chemiosmotic hypothesis for which he was awarded the Nobel Prize for Chemistry in 1978. His comprehensive review on chemiosmotic coupling known as the first “Grey Book”, has been reprinted here with permission, to offer an electronic record and easy access to this important contribution to the biochemical literature. This remarkable account of Peter Mitchell's ideas originally published in 1966 is a landmark and must-read publication for any scientist in the field of bioenergetics. As far as was possible, the wording and format of the original publication have been retained. Some changes were required for consistency with BBA formats though these do not affect scientific meaning. A scanned version of the original publication is also provided as a downloadable file in Supplementary Information. See also Editorial in this issue by Peter R. Rich. Original title: CHEMIOSMOTIC COUPLING IN OXIDATIVE AND PHOTOSYNTHETIC PHOSPHORYLATION, by Peter Mitchell, Glynn Research Laboratories, Bodmin, Cornwall, England.h Laboratories, Bodmin, Cornwall, England.)
ESCI 2021 Virtual + (55th ESCI meeting, Virtual, 2021)
ESCI 2022 Bari IT + (56th ESCI meeting, Bari, Italy, 2022)
ESCI 2023 Prague CZ + (57th ESCI meeting, Prague, Czech Republic, 2023)
Targeting Mitochondria World Congress 2014 + (5th Targeting Mitochondria World Congress - [http://www.targeting-mitochondria.com/ Targeting Mitochondria], Berlin DE)
5th Academic Symposium of Metabolic Biology Branch of Chinese Biophysical Society 2022 Zunyi CN + (5th Academic Symposium of Metabolic Biology Branch of Chinese Biophysical Society, Zunyi, China, 2022)
5th International Conference of Mitochondrial Medicine + (5th International Mitochondrial Medicine Conference Mitochondrial, Online, 2021)
NHLBI Mitochondrial Biology Symposium 2019 Bethesda US + (5th NHLBI Mitochondrial Biology Symposium, … 5th NHLBI Mitochondrial Biology Symposium, Bethesda, Maryland, USA, 2019 == General information == ::::On September 26-27, 2019, experts from around the world will gather on the NIH Campus in Bethesda, Maryland to review advances in our understanding of how mitochondrial structure, function, and interactions within the cell contribute to diseases and aging; and to highlight recent progress made with animal models and therapeutic interventions.== Venue == :::: William H. Natcher Conference Center – Building 45:::: National Institutes of Health:::: 45 Center Drive:::: Bethesda, MD 20814:::: [https://2019mbs.com/meeting-venue/ How to get there]== Organizer ==:::: [https://2019mbs.com/organizers/ Information available here]== Programme ==:::: [https://2019mbs.com/agenda/ Agenda]== Speakers == :::: List of speakers can be found [https://2019mbs.com/featured-speakers/ here]== Registration ==:::: [https://www.eventbrite.com/e/the-2019-nhlbi-mitochondrial-biology-symposium-registration-54765893261 Registration and more information]:::: The abstracts submission deadline is Friday, June 28, 2019, at 11:59PM EST. :::: All submissions must be made through the abstract submission portal. :::: Abstracts should be no longer than 500 words and include four clearly identifiable components: Background, Methods, Results, and Conclusion. :::: Abstracts will be reviewed by the Organizing Committee. Acceptance will be based on the quality of the abstract and availability of space. Four high-quality abstracts will be selected for oral presentation.ts will be selected for oral presentation.)
5th edition Metabolism & Cancer 2023 Nice FR + (5th edition Metabolism & Cancer, Nice, … 5th edition Metabolism & Cancer, Nice, France, 2023 == Venue ==:::: [https://www.metabolism-cancer.com/?utm_source=altemail&utm_medium=email&utm_campaign=2023-01-04%20METABO%202023%201 How to get there]== Program ==:::: Program available [https://www.metabolism-cancer.com/?utm_source=altemail&utm_medium=email&utm_campaign=2023-01-04%20METABO%202023%201 here]== Organizers ==:::: The list of organizers can be found [https://www.metabolism-cancer.com/?utm_source=altemail&utm_medium=email&utm_campaign=2023-01-04%20METABO%202023%201 here]== Registration ==:::: [https://www.metabolism-cancer.com/?utm_source=altemail&utm_medium=email&utm_campaign=2023-01-04%20METABO%202023%201 Registration and more information]utm_campaign=2023-01-04%20METABO%202023%201 Registration and more information])
BPS19 2019 Baltimore US + (63rd Annual Meeting of the Biophysical Soc … 63rd Annual Meeting of the Biophysical Society, Baltimore, Maryland USA, 2019 == General information==:::: The Biophysical Society meeting is the only major scientific meeting in the United States that routinely includes bioenergetics and mitochondrial topics. The Bioenergetics, Mitochondria, and Metabolism Subgroup has its two symposia on the first day of the meeting, March 2nd, and these two symposia have a distinguished group of speakers who are leaders in the field of bioenergetics. == Venue == :::: Baltimore Convention Center:::: 1 W. Pratt Street:::: Baltimore, Maryland 21201::::[https://www.biophysics.org/2019meeting/hotel-travel Hotel and Travel]== Programme ==:::: [https://www.biophysics.org/2019meeting/program here]== Registration ==:::: [https://www.biophysics.org/2019meeting/registration Registration and more information]tration Registration and more information])
AMI 2023 Jhansi IN + (64th Annual International Conference of the Associate of Microbiologists of India, Jhansi, India, 2023)
BPS2023 San Diego US + (67th Annual Meeting of the Biophysical Society, San Diego, California, USA, 2023)
ISOTT 2017 Halle/Saale DE + (6th 45th Annual Meeting of the International Society on Oxygen Transport to Tissue (ISOTT), Halle/Saale, Germany.)
6th Annual Conference of Chinese Society for Neurobiological Control of Metabolism 2024 Quanzhou CN + (6th Annual Conference of Chinese Society for Neurobiological Control of Metabolism, Quanzhou, China, 2024)
SMRM2017 New Delhi IN + (6th Annual Conference of the Society for Mitochondrial Research and Medicine, New Delhi, India.)
MiPschool Copenhagen DK 2013 + (6th MiP''summer school'' on Mitochondrial Physiology, 2013 August 26-30, Copenhagen, Denmark.)
6th Biannual Meeting on Mitochondria Apoptosis & Cancer 2019 Prague CZ + (6th Biannual Meeting on Mitochondria Apoptosis & Cancer, Prague, Czech Republic, 2019)
6th EU-Cardioprotection Meeting 2021 Riga LV + (6th EU-Cardioprotection WG Meeting CA16625 on mito and metabolism as targets for cardioprotection., Virtual Event, 2021)
6th International Conference on Tumor Microenvironment and Cellular Stress 2019 Crete GR + (6th International Conference on Tumor Microenvironment and Cellular Stress: Signaling, Metabolism, Imaging and Therapeutic Targets, Chania, Crete, Greece, 2019)
6th Research Day Innsbruck AT + (6th Research Day, Innsbruck, Austria, 2023)
77th Annual Meeting of the JCA 2018 Osaka JP + (77th Annual Meeting of the Japanese Cancer Association at the Osaka International Convention Center and RIHGA, Osaka, Japan, 2018)
The 77th Japanese Society of Physical Fitness and Sports Medicine 2022 Tochigi JP + (77th Japanese Society of Physical Fitness and Sports Medicine, Tochigi, 2022)
ISOTT 2018 Seoul KR + (7th 46th Annual Meeting of the International Society on Oxygen Transport to Tissue (ISOTT). Seoul, South Korea, 2018)
ISAP 2021 Virtual + (7th Conference of the International Society for Applied Phycology - ISAP2021, Tsukuba, Japan, 2021)
7th European Phycological Congress 2019 Zagreb HR + (7th European Phycological Congress, Zagreb, Croatia, 2019)
7th Molecular Mechanisms of Axon Degeneration Meeting Loch Lomond GB + (7th Molecular Mechanisms of Axon Degeneration Meeting, Loch Lomond, Scotland, Great Britain, 2019)
7th World Congress on Targeting Microbiota 2019 Krakow PL + (7th World Congress on Targeting Microbiota … 7th World Congress on Targeting Microbiota, Krakow, Poland, 2019 == Venue == :::: Park Inn by Radisson Krakow Hotel:::: Ul. Monte Cassino 2 PL:::: 30337 - Krakow - Poland:::: [https://www.microbiota-site.com/venue.html More information]== Organizer ==:::: [https://www.microbiota-site.com/committee.html Information available here]== Programme ==:::: [https://www.microbiota-site.com/images/2019/PDF/Targeting_Microbiota_2019_Agenda_-_V7.pdf Agenda]== Speakers == :::: List of speakers can be found [https://www.microbiota-site.com/microbiota-2019-speakers.html here]== Registration ==:::: [https://www.microbiota-site.com/registrations.html Registration and more information]ns.html Registration and more information])
MiPschool London 2015 + (8th MiP''school'' on Mitochondrial Physiology, 2015 Apr 20-24, London, UK.)
SMRM2020 Virtual + (8th Annual Meeting of the Society for Mitochondria Research and Medicine-India , Virtual.)
8th SMRM and Mitochondria-Metabolism Network Meeting 2020 Pune IN + (8th SMRM and Mitochondria-Metabolism Netwo … 8th SMRM and Mitochondria-Metabolism Network Meeting, Pune, India, 2020 == General information == :::: Flyer available for [https://www.mitoeagle.org/images/b/b2/8th_SMRM_and_Mitochondria-Metabolism_Network_Meeting_Poster.pdf download]== Venue == :::: Indian Institute of Science Education and Research (ISER Pune):::: Dr. Homi Bhabha Road:::: Pashan, Pune 411 008:::: INDIA::::[http://www.iiserpune.ac.in/facilities/guesthouse-cum-convention-centre Hotel and Travel]== Programme ==:::: [https://indico.tifr.res.in/indico/internalPage.py?pageId=12&confId=7288 here]== Speakers == :::: List of speakers can be found [https://indico.tifr.res.in/indico/internalPage.py?pageId=0&confId=7288 here]== Organizers ==:::: The list of organizers can be found [https://indico.tifr.res.in/indico/internalPage.py?pageId=9&confId=7288 here]== Registration ==:::: [https://indico.tifr.res.in/indico/internalPage.py?pageId=6&confId=7288 Registration and more information]ageId=6&confId=7288 Registration and more information])
TriMAD Sysposium 2018 Pennsylvania US + (8th Translational Research in Mitochondria … 8th Translational Research in Mitochondria, Aging, and Disease (TRiMAD) Symposium, Pennsylvania, United States, 2018 == General information ==:::: TRiMAD is a collaborative venture between The Pennsylvania State University, University of Pittsburgh Medical Center, The Children’s Hospital of Philadelphia (CHoP) Research Institute, and The University of Pennsylvania Perelman School of Medicine ([https://www.huck.psu.edu/node/15830 Website])== Venue == :::: The Pennsylvania State University:::: 100 Huck Life Sciences Building:::: University Park, Pennsylvania 16802:::: [http://www.cvent.com/events/8th-regional-translational-research-in-mitochondria-aging-and-disease-symposium/directions-16730cf0fe2c47a1b79f1a3b9ab0b364.aspx directions]== Organizers ==:::: Kateryna Makova, PhD - Penn State, University Park:::: Donna Korzick, PhD - Penn State, University Park[[File:Image001.jpg|right|550px]]== Programme ==:::: Please find the programme [http://www.cvent.com/events/8th-regional-translational-research-in-mitochondria-aging-and-disease-symposium/agenda-16730cf0fe2c47a1b79f1a3b9ab0b364.aspx here]== Registration ==:::: [https://www.cvent.com/events/8th-regional-translational-research-in-mitochondria-aging-and-disease-symposium/registration-16730cf0fe2c47a1b79f1a3b9ab0b364.aspx?fqp=true Register here] == Lecturers and tutors ==:::: The list of speakers can be found [http://www.cvent.com/events/8th-regional-translational-research-in-mitochondria-aging-and-disease-symposium/custom-18-16730cf0fe2c47a1b79f1a3b9ab0b364.aspx here]6730cf0fe2c47a1b79f1a3b9ab0b364.aspx here])
SBC 2023 Goa IN + (92nd Annual Meet of The Society of Biological Chemists, Goa, India, 2023)
Annual Meeting of the DPG 2016 Luebeck DE + (95th Annual Meeting of the DPG, [http://www.dpg2016.de/ DPG 2016], Luebeck, DE)
ASMRM 2012 Bejing CN + (9th Conference of t … 9th Conference of the Asian Society of Mitochondrial Research and Medicine and 5th Conference of Chinese Society of Mitochondrial Research and Medicine (Chinese-Mit), [http://asmrm2012.csp.escience.cn/dct/page/65540 ASMRM 2012], Bejing CN://asmrm2012.csp.escience.cn/dct/page/65540 ASMRM 2012], Bejing CN)
DNA Forensics 2014 + (9th International Y-chromosome workshop & 6th International EMPOP meeting, Brussels, Belgium; DNA Forensics 2014)
MiPschool Greenville 2015 + (9th MiP''school'' f … 9th MiP''school'' for cellular bioenergetics and mitochondrial physiology students, 2015 Aug 10-14, Greenville, US.» [http://www.ecu.edu/cs-admin/news/mip.cfm '''Global conference highlights mitochondria expertise at ECU'''], by Kathryn Kennedy ECU News Services.tise at ECU'''], by Kathryn Kennedy ECU News Services.)
SMRM2023 Hyderabad IN + (9th Annual Conference of the SMRM, Hyderabad, India.)
9th ÖGMBT Annual Meeting & 8th Life Science Meeting 2017 Innsbruck AT + (9th ÖGMBT Annual Meeting & 8th Life Science Meeting, Innsbruck, Austria)
Crispim 2019 MitoFit Preprint Arch EA + ( ::: Version 2 ('''v2''') '' … ::: Version 2 ('''v2''') '''2019-06-27''' [https://www.mitofit.org/images/6/68/Crispim_2019_MitoFit_Preprint_Arch_doi_10.26124mitofitea19.MiPSchool.0007.v2.pdf doi:10.26124/mitofit:ea19.MiPSchool.0007.v2]; v1 2019-06-17 [https://wiki.oroboros.at/images/8/81/Crispim_2019_MitoFit_Preprint_Arch_doi_10.26124mitofitea19.MiPSchool.0007.pdf doi:10.26124/mitofit:ea19.MiPSchool.0007]::: Version 1 (v1) [https://wiki.oroboros.at/images/8/81/Crispim_2019_MitoFit_Preprint_Arch_doi_10.26124mitofitea19.MiPSchool.0007.pdf doi:10.26124/mitofit:ea19.MiPSchool.0007]== Although atovaquone is one of the newest antimalarial compounds discovered, resistant parasites have already been reported1. Atovaquone mechanism of action is established to be the competition with ubiquinol (UQH2) for the bc1 union at mitochondrial cytochrome bc1 complex and preventing the parasite from maintaining an oxidized ubiquinone (UQ) pool, essential for the DHODH activity and consequently for the pyrimidine's biosynthesis. In this sense, possible inhibitors of the ubiquinone biosynthesis pathway would be candidates by stimulating the effects of atovaquone. 4-nitrobenzoate (4-NB) is a well-known inhibitor of 4HPT (4-hydroxybenzoate polyprenyltransferase), the first enzyme of UQ biosynthesis. 4-NB also showed an important effect on reducing the UQs pool in P. falciparum. Herein is presenting the effect of atovaquone and 4-NB on parasitic respiration UQ biosynthesis. The purpose of this study was to better understand the atovaquone mechanism of action in a molecular scale, drug target potential of UQ biosynthesis. Oxygen consumption assays revealed 4-NB potentiates atovaquone mitochondrial effects and showed itself the ability to decrease the respiration rate. ==- ''Extended abstract''crease the respiration rate. == - ''Extended abstract'' )
Gnaiger 2019 MitoFit Preprints Editorial + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2019-04-24''' [http://www.mitofit.org/images/d/d3/Gnaiger_2019_MitoFit_Preprint_Arch_doi_10.26124_mitofit_190002.v2.pdf doi:10.26124/mitofit:190002.v2]::: Version 1 (v1) 2019-04-01 [http://www.mitofit.org/images/archive/d/d3/20190424180311%21Gnaiger_2019_MitoFit_Preprint_Arch_doi_10.26124_mitofit_190002.v2.pdf doi:10.26124/mitofit:190002] - [http://www.mitofit.org/index.php/File:Gnaiger_2019_MitoFit_Preprint_Arch_doi_10.26124_mitofit_190002.v2.pdf#Links_to_all_versions »Link to all versions«]A manuscript in preparation for publication on ‘Mitochondrial states and rates’ is the first preprint posted on ''[[MitoFit Preprints]]'' (Gnaiger ''et al'' 2019). It actually triggered the initiation of a preprint server for mitochondrial physiology and bioenergetics. This editorial presents the story behind starting ''MitoFit Preprints'', to develop a vision of science communication beyond traditional journal and preprint publication. This is an open invitation to scientists of mitochondrial physiology and bioenergetics to join the preprint community by submitting manuscripts as preprints. We face the ''reproducibility crisis'' in the battle to separate doubtful data from relevant information. This is linked to the ''inflation crisis'' emanating from an exponential increase of scientific articles published per day. Unsustainable exponential growth leads to the ''value-impact crisis'' in the struggle to forge scientific innovation into knowledge and community benefits. forge scientific innovation into knowledge and community benefits. )
Gnaiger 2020 MitoFit x + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2021-09-06''' [https://www.mitofit.org/images/4/4a/Gnaiger_MitoFit_Preprint_Arch_2020.4_doi_10.26214mitofit.200004.pdf doi:10.26124/mitofit:200004.v2]::: Version 1 ('''v1''') 2020-08-11 [https://wiki.oroboros.at/images/archive/4/4a/20210906072525%21Gnaiger_MitoFit_Preprint_Arch_2020.4_doi_10.26214mitofit.200004.pdf doi:10.26124/mitofit:200004] — [https://www.mitofit.org/index.php/File:Gnaiger_MitoFit_Preprint_Arch_2020.4_doi_10.26214mitofit.200004.pdf »Link to all versions«]“The International System of Units, the SI, has been used around the world as the preferred system of units, the basic language for science, technology, industry and trade since it was established in 1960.” This statement heralds the 9th edition of the SI released on 2019-May-20. An new approach was introduced by defining the SI base units ― and thus the abstract SI units in general ― by their relation to fixed numerical values of fundamental constants of nature. Previous definitions of abstract units relied on a reference to concrete individual things realized as material artefacts, such as the International Prototype of the Kilogram (IPK). The (general) abstract unit ‘kilogram’ had to be calibrated in balance against an (individual) ‘entetic’ unit defining “1 kg” as a reference for the unit of mass and the mole [mol] as the unit of amount. Now the SI defines the mole as the fixed number of entities given by the Avogadro constant ''N''A. The elementary charge ''e'' is a fixed number of charges per proton. Amount and charge are thus in a fixed relation to the count of elementary entities ''U''''X'' [x]. Count, amount, and charge are isomorphic elementary quantities. Amount and charge are linked to the count ''N''''X'' = ''N''∙''U''''X'' with elementary unit x by fixed conversion constants ''N''A-1 [mol∙x−1] and ''e'' [C∙x−1], respectively. The SI does not use the elementary unit x. This causes a number of formal inconsistencies as discussed in the present communication on Euclid’s unit, which is ''U''''X'', and Euclid’s number, which is a count ''N''''X''.sistencies as discussed in the present communication on Euclid’s unit, which is ''U''''X'', and Euclid’s number, which is a count ''N''''X''. )
Baglivo 2022 MitoFit-QC + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2022-05-09''' [https://wiki.oroboros.at/images/c/c8/Baglivo_2022_MitoFit-QC.pdf doi:10.26124/mitofit:2022-0018.v2]::: Version 1 (v1) 2022-05-05 [https://wiki.oroboros.at/images/archive/c/c8/20220506062726%21Baglivo_2022_MitoFit-QC.pdf doi:10.26124/mitofit:2022-0018.v1] - [https://wiki.oroboros.at/index.php/File:Baglivo_2022_MitoFit-QC.pdf »Link to all versions«][[File:Baglivo 2022 MitoFit QC graphical-abstract.png|right|300px|Graphical abstract]][[Baglivo 2022 Abstract Bioblast]]: Evaluation of instrumental reproducibility is a primary component of quality control to quantify the precision and limit of detection of analytical procedures. A pre-analytical instrumental standard operating procedure (SOP) is implemented in high-resolution respirometry consisting of: (''1'') a daily SOP-POS for air calibration of the polarographic oxygen sensor (POS) in terms of oxygen concentration ''c''O2 [µM]. This is part of the ''sensor test'' to evaluate POS performance; (''2'') a monthly SOP-BG starting with the SOP-POS followed by the ''chamber test'' quantifying the instrumental O2 background. The chamber test focuses on the slope d''c''O2/d''t'' [pmol∙s−1∙mL−1] to determine O2 consumption by the POS and O2 backdiffusion into the chamber as a function of ''c''O2 in the absence of sample. Finally, zero O2 calibration completes the sensor test. We applied this SOP in a 3-year study using 48 Oroboros O2k chambers. Stability of air and zero O2 calibration signals was monitored throughout intervals of up to 8 months without sensor service. Maximum drift over 1 to 3 days was 0.06 pmol∙s−1∙mL−1, without persistence over time since drift was <0.004 pmol∙s−1∙mL−1 for time intervals of one month, corresponding to a drift per day of 0.2 % of the signal at air saturation. Instrumental O2 background -d''c''O2/d''t'' was stable within ±1 pmol∙s−1∙mL−1 when measured at monthly intervals. These results confirm the instrumental limit of detection of volume-specific O2 flux at ±1 pmol∙s−1∙mL−1. The instrumental SOP applied in the present study contributes to the generally applicable internal quality control management ensuring the unique reproducibility in high-resolution respirometry. These results confirm the instrumental limit of detection of volume-specific O2 flux at ±1 pmol∙s−1∙mL−1. The instrumental SOP applied in the present study contributes to the generally applicable internal quality control management ensuring the unique reproducibility in high-resolution respirometry. )
Gainutdinov 2022 MitoFit + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2022-08-16''' [https://wiki.oroboros.at/images/5/5a/Gainutdinov_2022_MitoFit.pdf https://doi.org/10.26124/mitofit:2022-0015.v2]::: Version 1 (v1) 2022-04-21 [https://wiki.oroboros.at/images/archive/5/5a/20220816100352%21Gainutdinov_2022_MitoFit.pdf https://doi.org/10.26124/mitofit:2022-0015]- [https://wiki.oroboros.at/index.php/File:Gainutdinov_2022_MitoFit.pdf »Link to all versions«]Amyotrophic lateral sclerosis (ALS) is a progressive, devastating, neurodegenerative disorder affecting upper and lower motor neurons. Common mechanisms of ALS pathogenesis are believed to be the disturbance of calcium homeostasis in the cell and dysfunction of mitochondria. Both factors mutually influence each other. As a result, chronic mitochondrial energy stress impairs fine cellular signaling and transport processes, leading to degeneration of motor neurons. In the current study we comparatively evaluated the cytosolic Ca2+ in healthy and ALS fibroblasts. We found that the mitochondrial calcium capacity in fibroblasts obtained from patients with sporadic (sALS) and familial (fALS) ALS differs between two subtypes and from that in healthy individuals. The changes of [Ca2+]cyt dynamics in ALS fibroblasts could be almost completely rescued by treatment with antioxidants (Trolox and CoQ10). These data confirm an important role of oxidative stress as a causative factor of mitochondrial dysfunction in ALS.portant role of oxidative stress as a causative factor of mitochondrial dysfunction in ALS. )
Alencar 2022 MitoFit + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2022-07-07''' [https://wiki.oroboros.at/images/5/54/Alencar_2022_MitoFit.pdf doi:10.26124/mitofit:2022-0009.v2]::: Version 1 (v1) 2022-04-07 [https://wiki.oroboros.at/images/archive/5/54/20220707123437%21Alencar_2022_MitoFit.pdf doi:10.26124/mitofit:2022-0009.v1] - [https://wiki.oroboros.at/index.php/File:Alencar_2022_MitoFit.pdf »Link to all versions«][[Oliveira 2022 Abstract Bioblast]]: The parasite ''Trypanosoma brucei'' is the causative agent of sleeping sickness and involves an insect vector and a mammalian host through its complex life-cycle. ''T. brucei'' mammalian bloodstream forms (BSF) exhibit unique metabolic features including: ''i)'' reduced expression and activity of mitochondrial enzymes; ''ii)'' respiration mediated by the glycerol phosphate shuttle (GPSh) and the ''Trypanosome'' alternative oxidase (TAO) that is intrinsically uncoupled from generation of mitochondrial membrane potential; ''iii)'' maintenance of mitochondrial membrane potential by ATP hydrolysis through the reversal of F1Fo ATP synthase activity; ''iv)'' strong reliance on glycolysis to meet their energy demands; ''v)'' high susceptibility to oxidants. Here, we critically review the main metabolic features of BSF and provide a hypothesis to explain the unusual metabolic network and its biological significance for this parasite form. We postulate that intrinsically uncoupled respiration provided by GPSh-TAO system would act as a preventive antioxidant defense by limiting mitochondrial superoxide production and complementing the NADPH-dependent scavenging antioxidant defenses to maintain parasite redox balance. Given the uncoupled nature of the GPSh-TAO system, BSF would avoid programmed cell death processes by maintaining mitochondrial membrane potential through the reversal of ATP synthase activity using the ATP generated by glycolysis. This unique “metabolic design” in BSF has no biological parallel outside of Trypanosomatids and highlights the enormous diversity of the parasite mitochondrial processes to adapt to distinct environments.parasite mitochondrial processes to adapt to distinct environments. )
Ganguly 2022 MitoFit + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2022-11-10''' [https://wiki.oroboros.at/images/6/64/Ganguly_2022_MitoFit.pdf https://doi.org/10.26124/mitofit:2022-0013.v2]::: Version 1 (v1) 2022-04-19 [https://wiki.oroboros.at/images/archive/6/64/20221110103433%21Ganguly_2022_MitoFit.pdf https://doi.org/10.26124/mitofit:2022-0013]- [https://wiki.oroboros.at/index.php/File:Ganguly_2022_MitoFit.pdf »Link to all versions«]Ferroptosis has been identified as a type of regulated cell death triggered by a diverse set of agents with implications in various diseases like cancer and neurodegenerative diseases. Ferroptosis is iron-dependent and accompanied by an accumulation of reactive oxygen species (ROS) and lipid oxidation products, a depletion of reduced glutathione, mitochondrial morphological alterations and the rupture of cell membrane; the process is inhibited by specific antioxidants like ferrostatin-1 and liproxstatin-1 and by other general antioxidants like the iron-chelator deferoxamine, vitamin E and N-acetylcysteine. However, the mechanism of cell death in ferroptosis subsequent to the accumulation of ROS and lipid oxidation products is not clearly established. We show here that the classical mitochondrial Complex I inhibitor rotenone (0.5 µM) causes death of SH-SY5Y cells (a human neuroblastoma cell line) over a period of 48 h accompanied by mitochondrial membrane depolarization and intracellular ATP depletion. This is associated with an intracellular accumulation of ROS and the lipid oxidation product malondialdehyde or MDA and a decrease in reduced glutathione content. All these processes are inhibited very conspicuously by specific inhibitors of ferroptosis such as ferrostatin-1 and liproxstatin-1. However, the decrease in Complex I activity upon rotenone-treatment of SH-SY5Y cells is not significantly recovered by ferrostatin-1 and liproxstatin-1. When the rotenone-treated cells are analyzed morphologically by Hoechst 33258 and propidium iodide (PI) staining, a mixed picture is noticed with densely fluorescent and condensed nuclei indicating apoptotic death of cells (Hoechst 33258) and also significant numbers of necrotic cells with bright red nuclei (PI staining).ant numbers of necrotic cells with bright red nuclei (PI staining). )
Roach 2022 MitoFit + ( ::: Version 2 ('''v2''') ''' … ::: Version 2 ('''v2''') '''2022-07-19''' [https://wiki.oroboros.at/images/d/d6/Roach_2022_MitoFit.pdf doi:10.26124/mitofit:2022-0023.v2]::: Version 1 (v1) 2022-06-03 [https://wiki.oroboros.at/images/archive/d/d6/20220719153447%21Roach_2022_MitoFit.pdf doi:10.26124/mitofit:2022-0023.v1] - [https://wiki.oroboros.at/index.php/File:Roach_2022_MitoFit.pdf »Link to all versions«][[Roach 2022 Abstract Bioblast]]: Tolerance of rapid changes in light intensity by photosynthetic organisms is facilitated by non-photochemical quenching (NPQ), a term with reference to quenching of chlorophyll fluorescence, the technique used in its discovery. Mechanisms of NPQ include dissipating excess light energy to heat (qE), the reversible attachment of light-harvesting complexes (LHC) to photosystems (state transition / qT) and photoinhibition (qI). Chlorophyll is a ubiquitous pigment of photosynthetic organisms, found in LHC and the reaction centres of photosystem II and I (PSII; PSI). At room temperature, pulse-amplitude modulated (PAM) chlorophyll fluorescence protocols provide insights into PSII efficiency, thus a reasonable proxy for photosynthetic activity (carbon fixation), at least under optimal conditions. NPQ has a major impact on chlorophyll fluorescence intensity and is also quantified by PAM. Since NPQ mechanisms can occur simultaneously, they cause complexities in deciphering the signal. In algae, the ability for chlorophyll fluorescence in determining photosynthetic rates is not perfect, but it can still provide valuable information of processes affecting light harvesting. The aim of this report is to provide an overview of how various NPQ mechanisms in the model unicellular chlorophyte alga, ''Chlamydomonas reinhardtii'', as well as environmental conditions, affect chlorophyll fluorescence. I also propose a PAM protocol enabling the kinetics associated with each of the NPQ phases to be semi-quantified in under 20 min. h of the NPQ phases to be semi-quantified in under 20 min. )
Di Marcello 2019 MitoFit Preprint Arch EA + ( ::: Version 3 ('"v3"') '''20 … ::: Version 3 ('"v3"') '''2019-07-03''' [https://www.mitofit.org/images/1/15/Di_Marcello_2019_MitoFit_Preprint_Arch_doi_10.26214mitofitea19.MiPSchool.0005.v2.pdf doi:10.26124/mitofit:ea19.MiPSchool.0005.v2.pdf]::: Version 2 (v2) 2019-06-27 [https://www.mitofit.org/images/1/15/Di_Marcello_2019_MitoFit_Preprint_Arch_doi_10.26214mitofitea19.MiPSchool.0005.v2.pdf doi:10.26124/mitofit:ea19.MiPSchool.0005.v2.pdf]::: Version 1 (v1) 2019-06-15 [http://www.mitofit.org/images/0/09/Di_Marcello_2019_MitoFit_Preprint_Arch.pdf doi:10.26124/mitofit:ea19.MiPSchool.0005]Bioenergetics is the study of how living organisms acquire and transform energy to perform biological work. Energetic coupling between chloroplasts and mitochondria has been described in algae, demonstrating the good functionality and interaction between both organelles is necessary to maintain metabolic integrity. High-resolution respirometry (HRR) is widely used to assess mitochondrial respiration and other bioenergetics parameters in the biomedical field of mitochondrial research and its clinical applications. In our interdisciplinary study, we adapted the multimodal approach of the Oroboros O2k high-resolution respirometer to investigate algal bioenergetics for biotechnological purposes. - ''Extended abstract''gate algal bioenergetics for biotechnological purposes. - ''Extended abstract'' )
Pallag 2022 MitoFit Proline + ( ::: Version 3 ('''v3''') ''' … ::: Version 3 ('''v3''') '''2022-03-07''' [https://wiki.oroboros.at/images/4/42/Pallag_2022_MitoFit_Proline.pdf doi:10.26124/mitofit:2022-0001.v3]::: Version 2 (v2) 2022-03-03 [https://wiki.oroboros.at/images/archive/4/42/20220307085642%21Pallag_2022_MitoFit_Proline.pdf doi:10.26124/mitofit:2022-0001.v2]::: Version 1 (v1) 2022-03-02 [https://wiki.oroboros.at/images/archive/4/42/20220303104356%21Pallag_2022_MitoFit_Proline.pdf doi:10.26124/mitofit:2022-0001] - [https://wiki.oroboros.at/index.php/File:Pallag_2022_MitoFit_Proline.pdf »Link to all versions«]In mitochondria expressing proline dehydrogenase (ProDH), oxidation of proline to pyrroline-5-carboxylate (P5C) leads to transfer of electrons to ubiquinone supporting Complexes CIII and CIV, in turn generating the protonmotive force. Further catabolism of P5C forms glutamate that fuels the citric acid cycle yielding reducing equivalents sustaining oxidative phosphorylation. However, P5C and glutamate catabolism depend on CI activity due to NAD+ requirement. The extent of proline oxidation was established in isolated mitochondria of various mouse tissues by means of simultaneously measuring oxygen consumption, membrane potential, NADH and ubiquinone redox state using the NextGen-O2k (Oroboros Instruments) and correlated to ProDH activity and F1FO-ATPase directionality. In CI-inhibited mouse liver and kidney mitochondria exhibiting high levels of proline oxidation and ProDH activity, catabolism of proline generated a sufficiently high membrane potential maintaining F1FO-ATPase operation in forward mode. This was not observed when either CIII or CIV was inhibited, nor during anoxia. Fueling CIII and CIV with duroquinone partially reproduced the effects of proline. Excess glutamate could not reproduce the effects of proline, arguing that they are due to processes upstream of glutamate conversion from proline. The ProDH inhibitors L-tetrahydro-2-furoic acid and to lesser extent S-5-oxo-2-tetrahydrofurancarboxylic acid abolished all effects conferred by proline. It is concluded that proline catabolism through ProDH generates sufficient CIII and CIV proton pumping, supporting ATP production by F1FO-ATPase even when CI is inhibited. production by F1FO-ATPase even when CI is inhibited. )
Gnaiger 2021 MitoFit BCA + ( ::: Version 1 ('''v1''') '''2021-09-21''' … ::: Version 1 ('''v1''') '''2021-09-21''' [https://www.mitofit.org/images/1/16/Gnaiger_2021_MitoFit_BCA.pdf doi:10.26124/mitofit:2021-0008][[File:Gnaiger 2021 MitoFit BCA-graphical abstract.png|right|300px|Graphical abstract]]Cell respiration reflects mitochondrial fitness and plays a pivotal role in health and disease. Despite the rapidly increasing number of applications of cell respirometry to address current challenges in biomedical research, cross-references are rare between respirometric projects and platforms. Evaluation of accuracy and reproducibility between laboratories requires presentation of results in a common format independent of the applied method. When cell respiration is expressed as oxygen consumption rate in an experimental chamber, normalization is mandatory for comparability of results. Concept-driven normalization and regression analysis are key towards bioenergetic cluster analysis presented as a graphical tool to identify discrete data populations.In a meta-analysis of human skin fibroblasts, high-resolution respirometry and polarography covering cell senescence and the human age range are compared with multiwell respirometry. The common coupling control protocol measures ROUTINE respiration of living cells followed by sequential titrations of oligomycin, uncoupler, and inhibitors of electron transfer.Bioenergetic cluster analysis increases the resolution of outliers within and differences between groups. An outlier-skewness index is introduced as a guide towards logarithmic transformation for statistical analysis. Isolinear clusters are separated by variations in the extent of a quantity that correlates with the rate, whereas heterolinear clusters fall on different regression lines. Dispersed clusters are clouds of data separated by a critical threshold value. Bioenergetic cluster analysis provides new insights into mitochondrial respiratory control and a guideline for establishing a quality control paradigm for bioenergetics and databases in mitochondrial physiology. bases in mitochondrial physiology. )
Donnelly 2022 MitoFit Hypoxia + ( ::: Version 2 ('''v2''') '''2022-07-15''' … ::: Version 2 ('''v2''') '''2022-07-15''' [https://wiki.oroboros.at/images/4/44/Donnelly_2022_MitoFit_Hypoxia.pdf The ABC of hypoxia – what is the norm https://doi.org/10.26124/mitofit:2022-0025.v2]::: Version 1 (v1) 2022-06-28 - [https://wiki.oroboros.at/index.php/File:Donnelly_2022_MitoFit_Hypoxia.pdf »Link to all versions«][[File:Oxia terms.png|right|250px]][[Donnelly 2022 Abstract Bioblast]]: Hypoxia is a condition of oxygen levels below normoxia and opposite to hyperoxia. We here define the normoxic reference state by three complementary precepts: ('''A''') ambient normoxia at sea level in the contemporary atmosphere and corresponding dissolved O2 concentration at air saturation of aqueous environments; ('''B''') biological compartmental O2 levels at ambient normoxia under physiological activity of healthy organisms in the absence of environmental stress (e.g. in a diving human, a stranded whale, a thermally stressed animal); and ('''C''') O2 levels above the control region, i.e., where the capacity for O2 consumption is not compromised by partial O2 pressure as evaluated by its kinetics. Conversely, the '''abc''' of hypoxia is concerned with deviations from these reference points caused by different mechanisms: ('''a''') ambient alterations of oxygen levels; ('''b''') biological O2 demand exceeding O2 supply under pathological or experimental limitations of convective O2 transport or O2 diffusion; and ('''c''') critical oxygen pressure in oxygen kinetics shifted by pathological and toxicological effects or environmental stress. The ABC of hypoxia may be of help in the design and interpretation of ''in vitro'' and ''in vivo'' experimental studies. ical effects or environmental stress. The ABC of hypoxia may be of help in the design and interpretation of ''in vitro'' and ''in vivo'' experimental studies. )
Cardoso 2021 MitoFit MgG + (<big>'''Journal publication 2021-06- … <big>'''Journal publication 2021-06-30 in [https://www.bioenergetics-communications.org/index.php/bec/article/view/cardoso_2021_mgg »Bioenergetics Communications 2021.1«]'''</big>For the advanced study of mitochondrial function, high-resolution respirometry is extended by fluorometric measurement of ATP production using the fluorophore Magnesium Green™ (MgG). A common problem with several fluorescent dyes is the inhibition of mitochondrial respiration. In the present study, a coupling control protocol was applied in combination with MgG to measure ATP production simultaneously with respiration for calculation of P»/O2 ratios. MgG at 1.1 µM did not affect respiration through the NADH-linked and succinate-linked pathways. Respiration was not inhibited in any of the coupling control states, hence coupling control efficiencies were not affected by MgG.tes, hence coupling control efficiencies were not affected by MgG.)
Krako Jakovljevic 2021 MitoFit PD + (<big>'''Journal publication 2021-10- … <big>'''Journal publication 2021-10-06 in [https://www.bioenergetics-communications.org/index.php/bec/article/view/krako_jakovljevic_2021_pd »Bioenergetics Communications 2021.2«]'''</big>Mitochondrial function is known to be an important factor in maintaining cellular homeostasis and its dysregulation has become a hallmark for multiple disease conditions. This review aims to synthesise the extent of this knowledge by analysing changes of mitochondrial physiology parameters in Parkinson’s disease (PD) and to evaluate the contribution of cellular models of PD in the field. The analysis provided here constitutes a platform for further elucidation of mitochondrial function parameters relative to factors that may potentiate disease progression.ve to factors that may potentiate disease progression.)
Vernerova 2021 MitoFit PLT + (<big>'''Journal publication 2021-12- … <big>'''Journal publication 2021-12-08 in [[Vernerova 2021 Biomedicines |''Biomedicines'']]'''</big>[[File:Vernerova 2021 Mitofit PLT - graphical abstract.png|right|300px|Graphical abstract]] Multiple non-aggregatory functions of human platelets (PLT) are widely acknowledged, yet their functional examination is limited mainly due to a lack of standardized isolation and analytic methods. Platelet apheresis (PA) is an established clinical method for PLT isolation aiming at the treatment of bleeding diathesis in severe thrombocytopenia. On the other hand, density gradient centrifugation (DC) is an isolation method applied in research for the analysis of the mitochondrial metabolic profile of oxidative phosphorylation (OXPHOS) in PLT obtained from small samples of human blood. We studied PLT obtained from 29 healthy donors by high-resolution respirometry for comparison of PA and DC isolates. ROUTINE respiration and electron transfer capacity of living PLT isolated by PA were significantly higher than in the DC group, whereas plasma membrane permeabilization resulted in a 57 % decrease of succinate oxidation in PA compared to DC. These differences were eliminated after washing the PA cells with phosphate buffer containing 10 mmol·L-1 EGTA, suggesting that several components, particularly Ca2+ and fuel substrates, were carried over into the respiratory assay from the serum in PA. A simple washing step was sufficient to enable functional mitochondrial analysis in subsamples obtained from PA.The combination of the standard clinical PA isolation procedure with PLT quality control and routine mitochondrial OXPHOS diagnostics meets an acute clinical demand in biomedical research of patients suffering from thrombocytopenia and metabolic diseases. h of patients suffering from thrombocytopenia and metabolic diseases. )
Komlodi 2021 MitoFit AmR-O2 + (<big>'''Journal publication 2021-12- … <big>'''Journal publication 2021-12-21 in [https://www.bioenergetics-communications.org/index.php/bec/article/view/komlodi_2021_amr »Bioenergetics Communications 2021.4«]'''</big>[[File:Komlodi 2021 MitoFit AmR-O2 graphical abstract.png|right|300px|Graphical abstract]]The fluorometric Amplex UltraRed AmR assay is frequently used for quantitative assessment of hydrogen peroxide production. It is specific to H2O2, can be calibrated accurately, and allows continuous real-time measurement. Without correction for the background fluorescence slope, however, H2O2-independent formation of the fluorescent product UltroxRed (or resorufin) leads to artefacts.We analysed (''1'') the medium specificity of the background fluorescence slope of the AmR assay, and (''2'') the oxygen dependence of H2O2 flux in baker´s yeast ''Saccharomyces cerevisiae''. Apparent H2O2 flux, O2 concentration and O2 flux were measured simultaneously by high-resolution respirometry equipped with the fluorescence module. The apparent H2O2 flux of yeast showed a maximum under hypoxia when incubated in Dulbecco´s Phosphate Buffered Saline DPBS or KCl-medium. This hypoxic peak increased with the sequential number of normoxic-anoxic transitions. Even in the absence of yeast, the fluorescence slope increased at low O2 levels as a function of fluorescence intensity. The hypoxic peak was not observed in mitochondrial respiration medium MiR05.Therefore, the hypoxic peak was a medium-specific background effect unrelated to cell physiology. In MiR05, H2O2 production of yeast decreased linearly from hyperoxia to hypoxia, with a steep decline towards anoxia. Respiration and oxygen dependence expressed as ''p''50 of yeast were higher in MiR05 than DPBS. Respiration was a hyperbolic function of oxygen concentration in the low-oxygen range. The flux-dependence of oxygen affinity explained the higher ''p''50 in MiR05. /sub> of yeast were higher in MiR05 than DPBS. Respiration was a hyperbolic function of oxygen concentration in the low-oxygen range. The flux-dependence of oxygen affinity explained the higher ''p''50 in MiR05. )
Buck 2013 Abstract MiP2013 + (<big>'''Peter Hochachka lecture'''&l … <big>'''Peter Hochachka lecture'''</big>Earth’s changing environment has been a major evolutionary force shaping the diversity of species both in the past and present. In particular, seasonal ice cover in northern latitudes has selected for hypoxia and anoxia tolerance in some species, such as freshwater turtles. At the northern reaches of their range North American western painted turtles spend 4 months or more buried in the mud bottom of ice covered lakes and ponds [1]. This offers a unique opportunity to understand how a vertebrate brain, an organ extremely sensitive to reduced oxygen availability in mammals, can function without oxygen [2]. Through oxidative phosphorylation mitochondria fuel the inherently high energetic demands of brain and in mammals mitochondria also play a key role in injury from hypoxic stress – including loss of calcium homeostasis and production of reactive oxygen species (ROS) leading to apoptosis and necrosis. Hypoxic or anoxic stress does not signal stress in turtle brain but rather protective mechanisms with the onset of anoxia. Indeed our data show that mitochondria play a key role in low oxygen signaling in turtle brain by a reduction in mitochondrial membrane potential and release of a relatively small but significant amount of calcium. The increase in cytosolic calcium signals a phosphatase based mechanism to decrease whole-cell glutamatergic (NMDA and AMPA) excitatory currents in pyramidal neurons. While in stellate neurons anoxia results in a large reduction in mitochondrial ROS production that increases the magnitude of GABAergic inhibitory neurotransmission. The increased GABA activity produces a chloride based shunting current that “arrests” action potentials in pyramidal cells resulting in metabolic depression and neuroprotection.resulting in metabolic depression and neuroprotection.)
Weber 2013 Abstract MiP2013 + (<big>'''[[Johansen K|Kjell Johansen]] … <big>'''[[Johansen K|Kjell Johansen]] lecture'''</big>Vertebrate hemoglobins (Hb) are exquisitely designed to transport O2 from the respiratory organs to the tissues, thereby safeguarding mitochondrial O2 supply and aerobic metabolism in the face of wide and independent variations in O2 tensions and temperature at the sites for loading and unloading of O2 [1-3]. In transporting O2, vertebrate Hbs (composed of 2 α and 2 β globin chains) switch between the T (tense, low O2-affinity, deoxygenated) structure that predominates in the tissues, and the R (relaxed, high-affinity, oxygenated) structure that predominates in the lungs and gills. The T-R shift is basic to cooperativity between the O2-binding heme groups that increases O2 (un)loading for a given change in O2 tension - and is reflected in the sigmoid shape of O2 binding curves. Hb’s in vivo O2 binding properties are a product of its intrinsic O2 affinity and its interaction with red cell allosteric effectors that decreases Hb-O2 affinity by stabilizing the T-structure. Apart from protons and CO2 (that facilitate O2 unloading in the acid tissues via the “Bohr-effect”) these effectors include chloride ions and organic phosphates [ATP in lower vertebrates, IPP (inositol pentaphosphate) in birds and DPG (diphosphoglycerate) in mammals]. The interaction with effectors varies between and within individual species and plays a key role in adjusting O2 transport in response to changes in environmental conditions, metabolic requirements, and mode of life. The decrease in Hb-O2 affinity with rising temperature mandated by the exothermic nature of heme oxygenation, enhances O2 unloading in warm tissues that require more O2, but may become maladaptive – and thus commonly is reduced - in regional heterothermic species where it may hamper O2 unloading (in cold extremities of arctic mammals) or cause excessive O2 release (in warm muscles, brains or eyes of fast-swimming fish).Based on case studies (Hbs from estivating fish, fast-swimming gamefish, high-altitude Andean frogs, geese that scale the Himalayas, Rocky Mountain Deer mice and Hb recreated from extinct mammoths [4-6]) the treatise analyses the molecular mechanisms for Hb’s role in securing mitochondrial O2 supply under stressful conditions - illustrating the key significance of molecular interactions to understanding physiological ecology. of molecular interactions to understanding physiological ecology.)
Walker 2013 Abstract MiP2013 + (<big>MiP2013 Keynote by Sir John Wal … <big>MiP2013 Keynote by Sir John Walker</big>The lecture will be devoted to the topic of how the biological world supplies itself with energy to make biology work, and what medical consequences ensue when the energy supply chain in our bodies is damaged or defective. We derive our energy from sunlight, which, via photosynthesis in green plants, provides high energy components in the foods that we ingest. We harvest that energy, effectively by “burning” (oxidising) the high energy components, releasing cellular energy in a controlled way to generate the fuel of life, in the form of the molecule known as adenosine triphosphate (or ATP for short). The key steps in this process take place in the mitochondria inside the cells that make up our tissues. They serve as biological “power stations” that contain millions of tiny molecular turbines, the ATP synthase, that rotate rather like man-made turbines churning out the cellular fuel in massive quantities, which is then delivered to all parts of our bodies to provide the energy to make them function. Each of us makes and expends about 60 kg of this fuel every day of our lives. Defects in the fuel supply process are increasingly being recognised as important components of complex human diseases such as cancer, neurodegeneration and neuromuscular diseases, and they may also be part of the process of ageing. The ATP synthases found in mitochondria, eubacteria and chloroplasts have many common features. Their overall architectures are similar, and they all consist of two rotary motors linked by a stator and a flexible rotor. When rotation of the membrane bound rotor is driven by proton motive force, the direction of rotation ensures that ATP is made from ADP and phosphate in the globular catalytic domain. When ATP serves as the source of energy and is hydrolysed in the catalytic domain, the rotor turns in the opposite sense and protons are pumped outwards through the membrane domain, and away from the catalytic domain. The lecture will describe the common features of their catalytic mechanisms. However, the ATP synthase from mitochondria, eubacteria and chloroplasts differ most fundamentally in the energy cost that is paid to make each ATP molecule. The most efficient ATP synthase is found in the mitochondria from multicellular animals. The ATP synthases in unicellular organisms, and chloroplasts, pay various higher costs that seem to reflect the supply of available energy in the biological niches that they inhabit. The ATP synthases also differ significantly in the way they are regulated. Eubacteria have evolved a range of mechanisms of regulation, and the chloroplast enzyme is rendered inactive by a redox mechanism in the hours darkness. Mitochondria contain an inhibitor protein, IF1, that inhibits ATP hydrolysis but not ATP synthesis. Its in vitro mechanism has been studied in great detail, but its in vivo role is mysterious, and suppression of expression of the protein appears not to influence respiration.In mitochondria the ATP synthase is organised in rows of dimers along the edges of the cristae, and as will be discussed, it has been suggested that the permeability transition pore involved in apoptosis resides in the dimeric enzyme.e involved in apoptosis resides in the dimeric enzyme.)
Lemieux 2017 bioRxiv 103457 + ( '''Lemieux H, Blier PU, Gnaig … '''Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of mitochondrial respiratory capacity by temperature in mouse heart: electron flow through the Q-junction in permeabilized fibers. Sci Rep 7:2840, DOI:10.1038/s41598-017-02789-8.''' - [[Lemieux 2017 Sci Rep |»Bioblast link«]]* Accepted for publication: 2017-04-18* [http://rdcu.be/tgpY Sci Rep Open Access]: 2017-06-06://rdcu.be/tgpY Sci Rep Open Access]: 2017-06-06)
OroDM01 Innsbruck AT + ( '''Oroboros Distributor Meeting'''. Innsbruck, Austria; 2019 Jul 01-03.)
2nd Oroboros distributor training 2023 Innsbruck AT + ( '''Oroboros distributor training'''. Innsbruck, Austria; 2023 Nov 07-09.)
Oroboros distributor training 2023 Innsbruck AT + ( '''Oroboros distributor training'''. Innsbruck, Austria; 2023 Apr 24-25.)
MiP2015 Book of Abstracts Open Access + ( : » [[MiP2015]] - all abstracts in alphabetical order and programme sessions. : » [[MiP2015 Abstracts in the MiPMap]] - sort by MiP''areas'', species, tissues, diseases, ...)
Chung 2005 Am J Physiol Cell Physiol + (1H-NMR experiments … 1H-NMR experiments have determined intracellular O2 consumption (''V''O2) with oxymyoglobin (MbO2) desaturation kinetics in human calf muscle during plantar flexion exercise at 0.75, 0.92, and 1.17 Hz with a constant load. At the onset of muscle contraction, myoglobin (Mb) desaturates rapidly. The desaturation rate constant of approximately 30 s reflects the intracellular ''V''O2. Although Mb desaturates quickly with a similar time constant at all workload levels, its final steady-state level differs. As work increases, the final steady-state cellular ''P''O2 decreases progressively. After Mb desaturation has reached a steady state, however, ''V''O2 continues to rise. On the basis of current respiratory control models, the analysis in the present report reveals two distinct ''V''O2 phases: an ADP-independent phase at the onset of contraction and an ADP-dependent phase after Mb has reached a steady state. In contrast to the accepted view, the initial intracellular ''V''O2 shows that oxidative phosphorylation can support up to 36 % of the energy cost, a significantly higher fraction than expected. Partitioning of the energy flux shows that a 31 % nonoxidative component exists and responds to the dynamic energy utilization-restoration cycle (which lasts for only milliseconds) as postulated in the glycogen shunt theory. The present study offers perspectives on the regulation of respiration, bioenergetics, and Mb function during muscle contraction.ration cycle (which lasts for only milliseconds) as postulated in the glycogen shunt theory. The present study offers perspectives on the regulation of respiration, bioenergetics, and Mb function during muscle contraction.)
Cohn 1953 J Biol Chem + (A new reaction which occurs in oxida … A new reaction which occurs in oxidative phosphorylation associated with the electron transport system has been observed in rat liver mitochondria with α-ketoglutarate, β-hydroxybutyrate, and succinate as substrates. This reaction manifests itself by a replacement of O18 with normal oxygen in inorganic phosphate labeled with O18 and parallels the phosphorylation which is associated with the oxidation. The number of molecules of inorganic phosphate which participate in this reaction, calculated on the basis that a monoester of phosphate is involved, is several times higher than the number of high energy phosphate bonds that can be formed. The reaction does not occur at the substrate level oxidation of α-ketoglutarate and the evidence suggests that it occurs at every step in the electron transport system. This phosphate turnover reaction occurs only when phosphorylation is proceeding. Dinitrophenol suppresses the reaction. The omission of Mg++ or adenylic acid also suppresses the reaction. The reaction is abolished when succinate oxidation is catalyzed by a succinic oxidase preparation containing no phosphorylating system. The possibility that the reaction is due to a direct reaction of ATP, hydrolytic or otherwise, is eliminated. Various mechanisms which are consistent with the findings are discussed.stent with the findings are discussed.)
Kielley 1951 J Biol Chem + (A simplified procedure for preparing … A simplified procedure for preparing mitochondria suspensions from isotonic sucrose homogenates has been described. These preparations exhibit high rates of net 7 minute phosphorus formation from adenylic acid during the oxidation of α-ketoglutarate in the absence of inhibitors such as fluoride, and show very low dephosphorylating activities. It has been possible to study the complete phosphorylation of AMP in this system and to interpret the characteristics of this process on the basis of adenosinediphosphate as primary phosphate acceptor and the presence of a myokinase in mitochondria. The activity of this transphosphorylase has been directly determined and is of considerable magnitude. It has also been demonstrated that probably all of the myokinase is associated with the mitochondrial fraction. The changes in the characteristics of oxidative phosphorylation and adenosinetriphosphatase activity as the result of incubation of the enzyme at 28° in the absence of substrates have been studied. The inactivation of the phosphorylation system by aging has been considered in two phases, an initial lag phase which is completely reversible in short aging experiments and a permanent reduction in activity observed with more severely aged mitochondria. The initial very low ATPase activity of the mitochondria was increased to appreciable magnitudes by aging. All the characteristics of aging were prevented to a large extent by AMP, ADP, or ATP. a large extent by AMP, ADP, or ATP.)
Chance 1961 J Biol Chem-I + (A thermodynamically improbable reductio … A thermodynamically improbable reduction of pyridine nucleotide caused by the addition of succinate to isolated mitochondria has been demonstrated. The material so reduced exhibits kinetic responses, some of which can suggest its consideration as a member of the respiratory chain, but a quantitative examination of the kinetics of oxidation and reduction shows that only a small portion of the total respiratory activity in succinate oxidation passes through the diphosphopyridine nucleotide-linked pathway. The nature of the reduction product has been examined in heart, liver, and guinea pig kidney mitochondria and is found to be material absorbing at 340 mµ and having a fluorescence emission maximum at 440 mµ. Direct chemical assays on kidney mitochondria indicate that the reduced material is diphosphopyridine nucleotide. A preliminary evaluation of various hypotheses to explain this result leads us tentatively to reject hypotheses based upon a single pool of mitochondrial pyridine nucleotide in which diphosphopyridine nucleotide and succinate compete for oxidizing equivalents from the cytochrome chain. Further indication of the complexities of this reaction is that respiration can be initiated by succinate without measurable pyridine nucleotide reduction and that a transition from aerobiosis in state 3 to anaerobiosis (state 5) can lead to a higher oxidation level of pyridine nucleotide than was observed aerobically in state 4. These observations suggest that the presence of adenosine 5’-diphosphate inhibits pyridine nucleotide reduction under both aerobic and anaerobic conditions and support the possibility that an energy-linked reaction may be involved.nergy-linked reaction may be involved.)
Pesta 2011Abstract Mitochondrial Medicine-Diagnosis + (A 28-year-old former amateur cyclist demon … A 28-year-old former amateur cyclist demonstrated a sudden exercise intolerance and impairment in muscle function since March 2008 without clinical explanation. The main symptom was a decreased ergometric aerobic capacity by 50%. A specific defect of mitochondrial glutamate dehydrogenase (GDH) was indicated by lack of ADP stimulation in the presence of glutamate and subsequent rescue of respiration after addition of malate.e of respiration after addition of malate.)
Kancirova 2016 Physiol Res + (A 2×2 factorial design was used to evaluat … A 2×2 factorial design was used to evaluate possible preservation of mitochondrial functions in two cardioprotective experimental models, remote ischemic preconditioning and streptozotocin-induced ''diabetes mellitus'', and their interaction during ischemia/reperfusion injury (I/R) of the heart. Male Wistar rats were randomly allocated into four groups: control (C), streptozotocin-induced diabetic (DM), preconditioned (RPC) and preconditioned streptozotocin-induced diabetic (DM+RPC). RPC was conducted by 3 cycles of 5-min hind-limb ischemia and 5-min reperfusion. DM was induced by a single dose of 65 mg/kg streptozotocin. Isolated hearts were exposed to ischemia/reperfusion test according to Langendorff. Thereafter mitochondria were isolated and the mitochondrial respiration was measured. Additionally, the ATP synthase activity measurements on the same preparations were done. Animals of all groups subjected to I/R exhibited a decreased state 3 respiration with the least change noted in DM+RPC group associated with no significant changes in state 2 respiration. In RPC, DM and DM+RPC group, no significant changes in the activity of ATP synthase were observed after I/R injury. These results suggest that the endogenous protective mechanisms of RPC and DM do preserve the mitochondrial function in heart when they act in combination.ion in heart when they act in combination.)
Gaudo 2019 Neurogenetics + (A 3-year-old girl presented with severe ep … A 3-year-old girl presented with severe epilepsy in the context of ''Borrelia'' infection. After ceftriaxone/lidocaine administration, she showed secondarily generalized focal crises that led to neurological and motor sequelae. Genetic studies identified in the patient two heterozygous POLG mutations (c.2591A>G; p.Asn864Ser and c.3649G>C; p.Ala1217Pro). Through analysis of POLG activity in cultured fibroblasts, we confirmed that the mutations altered the mtDNA turnover. Moreover, patient fibroblasts were more sensitive than controls in the presence of a mitochondrial replication-affecting drug, the antiretroviral azidothymidine. To test if ceftriaxone treatment could worsen the deleterious effect of the patient mutations, toxicity assays were performed. Cell toxicity, without direct effect on mitochondrial respiratory function, was detected at different antibiotic concentrations. The clinical outcome, together with the different ''in vitro'' sensitivity to ceftriaxone among patient and control cells, suggested that the mitochondrial disease symptoms were hastened by the infection and were possibly worsened by the pharmacological treatment. This study underscores the benefit of early genetic diagnosis of the patients with mitochondrial diseases, since they may be a target group of patients especially vulnerable to environmental factors. especially vulnerable to environmental factors.)
Nijholt 2023 Sci Rep + (A Kinase Interacting Protein 1 (AKIP1) is … A Kinase Interacting Protein 1 (AKIP1) is a signalling adaptor that promotes mitochondrial respiration and attenuates mitochondrial oxidative stress in cultured cardiomyocytes. We sought to determine whether AKIP1 influences mitochondrial function and the mitochondrial adaptation in response to exercise ''in vivo''. We assessed mitochondrial respiratory capacity, as well as electron microscopy and mitochondrial targeted-proteomics in hearts from mice with cardiomyocyte-specific overexpression of AKIP1 (AKIP1-TG) and their wild type (WT) littermates. These parameters were also assessed after four weeks of voluntary wheel running. In contrast to our previous ''in vitro'' study, respiratory capacity measured as state 3 respiration on palmitoyl carnitine was significantly lower in AKIP1-TG compared to WT mice, whereas state 3 respiration on pyruvate remained unaltered. Similar findings were observed for maximal respiration, after addition of FCCP. Mitochondrial DNA damage and oxidative stress markers were not elevated in AKIP1-TG mice and gross mitochondrial morphology was similar. Mitochondrial targeted-proteomics did reveal reductions in mitochondrial proteins involved in energy metabolism. Exercise performance was comparable between genotypes, whereas exercise-induced cardiac hypertrophy was significantly increased in AKIP1-TG mice. After exercise, mitochondrial state 3 respiration on pyruvate substrates was significantly lower in AKIP1-TG compared with WT mice, while respiration on palmitoyl carnitine was not further decreased. This was associated with increased mitochondrial fission on electron microscopy, and the activation of pathways associated with mitochondrial fission and mitophagy. This study suggests that AKIP1 regulates the mitochondrial proteome involved in energy metabolism and promotes mitochondrial turnover after exercise. Future studies are required to unravel the mechanistic underpinnings and whether the mitochondrial changes are required for the AKIP1-induced physiological cardiac growth.KIP1-induced physiological cardiac growth.)
MiPNet17.12 Bioblast 2012 + (A Mitochondrial Festival in the Spirit of … A Mitochondrial Festival in the Spirit of [[Gentle Science]] <div style="padding:0px;border: 1px solid #aaaaaa;margin-bottom:0px;margin-right:10px"><div style="font-size:100%;font-weight:bold;padding:0.2em;padding-right: 0.4em;padding-left: 0.4em;background-color:#eeeeee;border-bottom:1px solid #aaaaaa;text-align:left;">[[Image:O2k-support system.jpg|right|150px|link=http://wiki.oroboros.at/index.php/O2k-technical_support_and_open_innovation|O2k-technical support and open innovation]]: <big>Open the '''pdf document''' above.</big></div><div style="background-color:#ffffff;padding-top:0.2em;padding-right: 0.4em;padding-bottom: 0.2em;padding-left: 0.4em;">::::» Current O2k-series: '''[https://www.oroboros.at/index.php/product-category/products/o2k-packages/ NextGen-O2k Series XB and O2k Series J]'''::::» Current software versions DatLab 8.0: [[MitoPedia: DatLab]]::::* ''Further details:'' '''» [[MitoPedia: O2k-Open Support]]'''</div></div>itoPedia: O2k-Open Support]]''' </div> </div>)
WHO Expert Consultation 2004 Lancet + (A WHO expert consultation addressed the de … A WHO expert consultation addressed the debate about interpretation of recommended body-mass index (BMI) cut-off points for determining overweight and obesity in Asian populations, and considered whether population-specific cut-off points for BMI are necessary. They reviewed scientific evidence that suggests that Asian populations have different associations between BMI, percentage of body fat, and health risks than do European populations. The consultation concluded that the proportion of Asian people with a high risk of type 2 diabetes and cardiovascular disease is substantial at BMIs lower than the existing WHO cut-off point for overweight (> or =25 kg/m2). However, available data do not necessarily indicate a clear BMI cut-off point for all Asians for overweight or obesity. The cut-off point for observed risk varies from 22 kg/m2 to 25 kg/m2 in different Asian populations; for high risk it varies from 26 kg/m2 to 31 kg/m2. No attempt was made, therefore, to redefine cut-off points for each population separately. The consultation also agreed that the WHO BMI cut-off points should be retained as international classifications. The consultation identified further potential public health action points (23.0, 27.5, 32.5, and 37.5 kg/m2) along the continuum of BMI, and proposed methods by which countries could make decisions about the definitions of increased risk for their population.tions of increased risk for their population.)
Hall 2019 Methods Mol Biol + (A better understanding of the molecular ba … A better understanding of the molecular basis of polycation-mediated impairment of mitochondrial bioenergetics might improve the design and synthesis of more efficient and safer polymeric transfectants. Here we utilize the phosphorylation control protocol for studying the effect of polycations on mitochondrial respiration in intact mammalian cells using Oxygraph-2k (OROBOROS). The protocol offers an opportunity to comprehensively monitor mitochondrial respiration through consecutive additions of various cell membrane permeable compounds that alter mitochondrial respiration, thus providing useful information on different states of mitochondrial respiration. Furthermore, we demonstrate how to analyze the data obtained with the phosphorylation control protocol and how to calculate the respiratory flux ratios, which can be used as indicators of respiratory functionality and mitochondrial health.ry functionality and mitochondrial health.)
Ritchie 2008 Photosyn Res + (A blue diode PAM (Pulse Amplitude Modulati … A blue diode PAM (Pulse Amplitude Modulation) fluorometer was used to measure rapid Photosynthesis (P) versus Irradiance (E) curves (P vs. E curves) in ''Synechococcus'' (classical cyanobacteria), ''Prochlorothrix'' (prochlorophyta), ''Chlorella'' (chlorophyta), ''Rhodomonas'' (cryptophyta), ''Phaeodactylum'' (bacillariophyta), ''Acaryochloris'' (Chl d/a cyanobacteria) and Subterranean Clover (''Trifolium subterraneum'', Papilionaceae, Angiospermae). Effective quantum yield (Phi(PSII)) versus irradiance curves could be described by a simple exponential decay function (Phi(PSII) = Phi(PSII, maxe(-kE)) although Log/Log transformation was sometimes found to be necessary to obtain the best fits. Photosynthesis was measured as relative Electron Transport Rate (rETR) standardised on a chlorophyll basis. P versus E curves were fitted to the waiting-in-line function (an equation of the form P = P(max) x k x E x e(-kE)) allowing half-saturating and optimal irradiances (E(optimum)) to be estimated. The second differential of the equation shows that at twice optimal light intensities, there is a point of inflection in the P versus E curve. Photosynthesis is inhibited 26.4% at this point of inflection. The waiting-in-line model was found to be a very good descriptor of photosynthetic light saturation curves and superior to hyperbolic functions with an asymptotic saturation point (Michaelis-Menten, exponential saturation and hyperbolic tangent). The exponential constants (k) of the Phi(PSII) versus E and P versus E curves should be equal because rETR is directly proportional to Phi(PSII) x E. The conventionally calculated Non-Photochemical Quenching (NPQ) in Synechococcus was not significantly different to zero but NPQ versus E curves for the other algae could be fitted to an exponential saturation model. The kinetics of NPQ does not appear to be related to the kinetics of Phi(PSII) or rETR.ated to the kinetics of Phi(PSII) or rETR.)
Mitophagy + (A brief accout of '''mitochondrial mitophagy'''.)
Sirtuins + (A brief accout of the '''sirtuin family'''.)
Hanna 2023 Antioxid Redox Signal + (A burgeoning literature has attributed var … A burgeoning literature has attributed varied physiological effects to hydrogen sulfide (H2S), which is a product of eukaryotic sulfur amino acid metabolism. Protein persulfidation represents a major focus of studies elucidating the mechanism underlying H2S signaling. On the contrary, the capacity of H2S to induce reductive stress by targeting the electron transport chain (ETC) and signal by reprogramming redox metabolism has only recently begun to be elucidated. Recent Advances: In contrast to the nonspecific reaction of H2S with oxidized cysteines to form protein persulfides, its inhibition of complex IV represents a specific mechanism of action. Studies on the dual impact of H2S as an ETC substrate and an inhibitor have led to the exciting discovery of ETC plasticity and the use of fumarate as a terminal electron acceptor. H2S oxidation combined with complex IV targeting generates mitochondrial reductive stress, which is signaled through the metabolic network, leading to increased aerobic glycolysis, glutamine-dependent reductive carboxylation, and lipogenesis. Critical Issues: Insights into H2S-induced metabolic reprogramming are ushering in a paradigm shift for understanding the mechanism of its cellular action. It will be critical to reevaluate the physiological effects of H2S, for example, cytoprotection against ischemia-reperfusion injury, through the framework of metabolic reprogramming and ETC remodeling by H2S. Future Directions: The metabolic ramifications of H2S in other cellular compartments, for example, the endoplasmic reticulum and the nucleus, as well as the intersections between hypoxia and H2S signaling are important future directions that merit elucidation. future directions that merit elucidation.)
Okoye 2019 Aquat Toxicol + (A by-product of mitochondrial substrate ox … A by-product of mitochondrial substrate oxidation and electron transfer to generate cellular energy (ATP) is reactive oxygen species (ROS). Superoxide anion radical and hydrogen peroxide (H2O2) are the proximal ROS produced by the mitochondria. Because low levels of ROS serve critical regulatory roles in cell physiology while excessive levels or inappropriately localized ROS result in aberrant physiological states, mitochondrial ROS need to be tightly regulated. While it is known that regulation of mitochondrial ROS involves balancing the rates of production and removal, the effects of stressors on these processes remain largely unknown. To illuminate how stressors modulate mitochondrial ROS homeostasis, we investigated the effects of temperature and cadmium (Cd) on H2O2 emission and consumption in rainbow trout liver mitochondria. We show that H2O2 emission rates increase with temperature and Cd exposure. Energizing mitochondria with malate-glutamate or succinate increased the rate of H2O2 emission; however, Cd exposure imposed different patterns of H2O2 emission depending on the concentration and substrate. Specifically, mitochondria respiring on malate-glutamate exhibited a saturable graded concentration-response curve that plateaued at 5 μM while mitochondria respiring on succinate had a biphasic concentration-response curve characterized by a spike in the emission rate at 1 μM Cd followed by gradual diminution at higher Cd concentrations. To explain the observed substrate- and concentration-dependent effects of Cd, we sequestered specific mitochondrial ROS-emitting sites using blockers of electron transfer and then tested the effect of the metal. The results indicate that the biphasic H2O2 emission response imposed by succinate is due to site IIF but is further modified at sites IQ and IIIQo. Moreover, the saturable graded H2O2 emission response in mitochondria energized with malate-glutamate is consistent with effect of Cd on site IF. Additionally, Cd and temperature acted cooperatively to increase mitochondrial H2O2 emission suggesting that increased toxicity of Cd at high temperature may be due to increased oxidative insult. Surprisingly, despite their clear stimulatory effect on H2O2 emission, Cd, temperature and bioenergetic status did not affect the kinetics of mitochondrial H2O2 consumption; the rate constants and half-lives for all the conditions tested were similar. Overall, our study indicates that the production processes of rainbow trout liver mitochondrial H2O2 metabolism are highly responsive to stressors and bioenergetics while the consumption processes are recalcitrant. The latter denotes the presence of a robust H2O2 scavenging system in liver mitochondria that would maintain H2O2 homeostasis in the face of increased production and reduced scavenging capacity.Copyright © 2019 Elsevier B.V. All rights reserved.The latter denotes the presence of a robust H2O2 scavenging system in liver mitochondria that would maintain H2O2 homeostasis in the face of increased production and reduced scavenging capacity. Copyright © 2019 Elsevier B.V. All rights reserved.)
Zweck 2023 ESC Heart Fail + (A causal link between non-ischaemic heart … A causal link between non-ischaemic heart failure (HF) and humoral autoimmunity against G-protein-coupled receptors (GPCR) remains unclear except for Chagas' cardiomyopathy. Uncertainty arises from ambiguous reports on incidences of GPCR autoantibodies, spurious correlations of autoantibody levels with disease activity, and lack of standardization and validation of measuring procedures for putatively cardio-pathogenic GPCR autoantibodies. Here, we use validated and certified immune assays presenting native receptors as binding targets. We compared candidate GPCR autoantibody species between HF patients and healthy controls and tested associations of serum autoantibody levels with serological, haemodynamic, metabolic, and functional parameters in HF.Ninety-five non-ischaemic HF patients undergoing transcatheter endomyocardial biopsy and 60 healthy controls were included. GPCR autoantibodies were determined in serum by IgG binding to native receptors or a cyclic peptide (for β1AR autoantibodies). In patients, cardiac function, volumes, and myocardial structural properties were assessed by cardiac magnetic resonance imaging; right heart catheterization served for determination of cardiac haemodynamics; endomyocardial biopsies were used for histological assessment of cardiomyopathy and determination of cardiac mitochondrial oxidative function by high-resolution respirometry.Autoantibodies against β1 adrenergic (β1AR) , M5-muscarinic (M5AR), and angiotensin II type 2 receptors (AT2R) were increased in HF (all P < 0.001). Autoantibodies against α1 -adrenergic (α1 AR) and angiotensin II type 1 receptors (AT1R) were decreased in HF (all P < 0.001). Correlation of alterations of GPCR autoantibodies with markers of cardiac or systemic inflammation or cardiac damage, haemodynamics, myocardial histology, or left ventricular inflammation (judged by T2 mapping) were weak, even when corrected for total IgG. β1 AR autoantibodies were related inversely to markers of left ventricular fibrosis indicated by T1 mapping (r = -0.362, P < 0.05) and global longitudinal strain (r = -0.323, P < 0.05). AT2R autoantibodies were associated with improved myocardial mitochondrial coupling as measured by high-resolution respirometry in myocardial biopsies (r = -0.352, P < 0.05). In insulin-resistant HF patients, AT2R autoantibodies were decreased (r = -.240, P < 0.05), and AT1R autoantibodies were increased (r = 0.212, P < 0.05).GPCR autoantibodies are markedly altered in HF. However, they are correlated poorly or even inversely to haemodynamic, metabolic, and functional markers of disease severity, myocardial histology, and myocardial mitochondrial efficiency. These observations do not hint towards a specific cardio-pathogenic role of GPCR autoantibodies and suggest that further investigations are required before specific therapies directed at GPCR autoantibodies can be clinically tested in non-ischaemic HF.rected at GPCR autoantibodies can be clinically tested in non-ischaemic HF.)
Mouithys-Mickalad 2020 Chem Biol Interact + (A cellular model of cardiomyocytes (H9c2 c … A cellular model of cardiomyocytes (H9c2 cell line) and mitochondria isolated from mouse liver were used to understand the drug action of BPDZ490 and BPDZ711, two benzopyran analogues of the reference potassium channel opener cromakalim, on mitochondrial respiratory parameters and swelling, by comparing their effects with those of the parent compound cromakalim. For these three compounds, the oxygen consumption rate (OCR) was determined by high-resolution respirometry (HRR) and their impact on adenosine triphosphate (ATP) production and calcium-induced mitochondrial swelling was investigated. Cromakalim did not modify neither the OCR of H9c2 cells and the ATP production nor the Ca-induced swelling. By contrast, the cromakalim analogue BPDZ490 (1) induced a strong increase of OCR, while the other benzopyran analogue BPDZ711 (2) caused a marked slowdown. For both compounds, 1 displayed a biphasic behavior while 2 still showed an inhibitory effect. Both compounds 1 and 2 were also found to decrease the ATP synthesis, with pronounced effect for 2, while cromakalim remained without effect. Overall, these results indicate that cromakalim, as parent molecule, does not induce per se any direct effect on mitochondrial respiratory function neither on whole cells nor on isolated mitochondria whereas both benzopyran analogues 1 and 2 display totally opposite behavior profiles, suggesting that compound 1, by increasing the maximal respiration capacity, might behave as a mild uncoupling agent and compound 2 is taken as an inhibitor of the mitochondrial electron-transfer chain.the mitochondrial electron-transfer chain.)
Valle-Mendiola 2020 Cancers (Basel) + (A central characteristic of many types of … A central characteristic of many types of cancer is altered energy metabolism processes such as enhanced glucose uptake and glycolysis and decreased oxidative metabolism. The regulation of energy metabolism is an elaborate process involving regulatory proteins such as HIF (pro-metastatic protein), which reduces oxidative metabolism, and some other proteins such as tumour suppressors that promote oxidative phosphorylation. In recent years, it has been demonstrated that signal transducer and activator of transcription (STAT) proteins play a pivotal role in metabolism regulation. STAT3 and STAT5 are essential regulators of cytokine- or growth factor-induced cell survival and proliferation, as well as the crosstalk between STAT signalling and oxidative metabolism. Several reports suggest that the constitutive activation of STAT proteins promotes glycolysis through the transcriptional activation of hypoxia-inducible factors and therefore, the alteration of mitochondrial activity. It seems that STAT proteins function as an integrative centre for different growth and survival signals for energy and respiratory metabolism. This review summarises the functions of STAT3 and STAT5 in the regulation of some metabolism-related genes and the importance of oxygen in the tumour microenvironment to regulate cell metabolism, particularly in the metabolic pathways that are involved in energy production in cancer cells.lved in energy production in cancer cells.)
Palade 1953 J Histochem Cytochem + (A characteristic pattern of organization w … A characteristic pattern of organization was found with the help of the electron microscope in sectioned animal mitochondria irrespective of the species providing the specimen and of the cell type examined.Each mitochondrion was found to possess:# A limiting membrane.# A mitochondrial matrix that appears structureless at present levels of resolution.# A system of internal ridges (cristae mitochondriales) that protrude from the inside surface of the membrane towards the interior of the organelles. In many mitochondria the cristae are perpendicular to the long axis of the organelles and occur in series within which they lie parallel to one another at more or less regular intervals.In favorable electron micrographs the mitochondrial membrane appears to be double and the cristae appear to be folds of a second, internal mitochondrial membrane.a second, internal mitochondrial membrane.)
Zeng 2017 J Biol Chem + (A chronic high fat diet results in hepatic … A chronic high fat diet results in hepatic mitochondrial dysfunction and induction of peroxisomal fatty acid oxidation (FAO); whether specific inhibition of peroxisomal FAO benefits mitochondrial FAO and reactive oxygen species (ROS) metabolism remains unclear. In this study a specific inhibitor for the rate-limiting enzyme involved in peroxisomal FAO, [[acyl-CoA oxidase]]-1 (ACOX1) was developed and used for the investigation of peroxisomal FAO inhibition upon mitochondrial FAO and ROS metabolism. Specific inhibition of ACOX1 by 10,12-tricosadiynoic acid increased hepatic mitochondrial FAO via activation of the SIRT1-AMPK (adenosine 5'-monophosphate-activated protein kinase) pathway and proliferator activator receptor α and reduced hydrogen peroxide accumulation in high fat diet-fed rats, which significantly decreased hepatic lipid and ROS contents, reduced body weight gain, and decreased serum triglyceride and insulin levels. Inhibition of ACOX1 is a novel and effective approach for the treatment of high fat diet- or obesity-induced metabolic diseases by improving mitochondrial lipid and ROS metabolism.ng mitochondrial lipid and ROS metabolism.)
Boczek 2014 Biomed Res Int + (A close link between Ca2+</s … A close link between Ca2+, ATP level, and neurogenesis is apparent; however, the molecular mechanisms of this relationship have not been completely elucidated. Transient elevations of cytosolic Ca2+ may boost ATP synthesis, but ATP is also consumed by ion pumps to maintain a low Ca2+ in cytosol. In differentiation process plasma membrane Ca2+ ATPase (PMCA) is considered as one of the major players for Ca2+ homeostasis. From four PMCA isoforms, the fastest PMCA2 and PMCA3 are expressed predominantly in excitable cells. In the present study we assessed whether PMCA isoform composition may affect energy balance in differentiating PC12 cells. We found that PMCA2-downregulated cells showed higher basal O2 consumption, lower NAD(P)H level, and increased activity of ETC. These changes associated with higher [Ca2+]c resulted in elevated ATP level. Since PMCA2-reduced cells demonstrated greatest sensitivity to ETC inhibition, we suppose that the main source of energy for PMCA isoforms 1, 3, and 4 was oxidative phosphorylation. Contrary, cells with unchanged PMCA2 expression exhibited prevalence of glycolysis in ATP generation. Our results with PMCA2- or PMCA3-downregulated lines provide an evidence of a novel role of PMCA isoforms in regulation of bioenergetic pathways, and mitochondrial activity and maintenance of ATP level during PC12 cells differentiation.soforms in regulation of bioenergetic pathways, and mitochondrial activity and maintenance of ATP level during PC12 cells differentiation.)
Yang 2010 Cancer Biol Ther + (A common metabolic change in cancer is the … A common metabolic change in cancer is the acquisition of glycolytic phenotypes. Increased expression of glycolytic enzymes is considered as one contributing factor. The role of mitochondrial defects in acquisition of glycolytic phenotypes has been postulated but remains controversial. Here we show that functional defects in mitochondrial respiration could be induced by oncogenic H-RasQ61L transformation, even though the mitochondrial contents or mass was not reduced in the transformed cells. First, mitochondrial respiration, as measured by mitochondrial oxygen consumption, was suppressed in NIH-3T3 cells transformed with H-RasQ61L. Second, oligomycin or rotenone did not reduce the cellular ATP levels in the H-RasQ61L transformed cells, suggesting a diminished role of mitochondrial respiration in the cellular energy metabolism. Third, inhibition of glycolysis with iodoacetic acid reduced ATP levels at a much faster rate in H-RasQ61L transformed cells than in the vector control cells. The reduction of cellular ATP levels was reversed by exogenously added pyruvate in the vector control cells but not in H-RasQ61L transformed cells. Finally when compared to the HRasQ61L transformed cells, the vector control cells had increased resistance toward glucose deprivation. The increased resistance was dependent on mitochondrial oxidative phosphorylation since rotenone or oligomycin abolished the increased survival of the vector control cells under glucose deprivation. The results also suggest an inability of the H-RasQ61L transformed cells to reactivate mitochondrial respiration under glucose deprivation. Taken together, the data suggest that mitochondrial respiration can be impaired during transformation of NIH-3T3 cells by oncogeneic H-RasQ61L.can be impaired during transformation of NIH-3T3 cells by oncogeneic H-RasQ61L.)
Jacobus 1982 Arch Biochem Biophys + (A complete kinetic analysis of the forward … A complete kinetic analysis of the forward mitochondrial creatine kinase reaction was conducted to define the mechanism for its rate enhancement when coupled to oxidative phosphorylation. Two experimental systems were employed. In the first, ATP was produced by oxidative phosphorylation. In the second, heart mitochondria were pretreated with rotenone and oligomycin, and ATP was regenerated by a phosphoenolpyruvate-pyruvate kinase system. Product inhibition studies showed that oxidative phosphorylation did not effect the binding of creatine phosphate to the enzyme. Creatine phosphate interacted competitively with both ATP and creatine, and the E · MgATP · CrP dead-end complex was not readily detected. In a similar manner, the dissociation constants for creatine were not influenced by the source of ATP: ''K''ib = 29 mM; ''K''b = 5.3 mM, and the maximum velocity of the reaction was unchanged: ''V''1 = 1 μmol/min/mg. Slight differences were noted for the dissociation constant (''K''ia) of MgATP from the binary enzyme complex, E · MgATP. The values were 0.75 and 0.29 mM in the absence and presence of respiration. However, a 10-fold decrease in the steady-state dissociation constant (''K''a) of MgATP from the ternary complex, E · MgATP · creatine, was documented: 0.15 mM with exogenous ATP and 0.014 mM with oxidative phosphorylation. Since ''K''ia × ''K''b does not equal ''K''a × ''K''ib under respiring conditions, the enzyme appears to be altered from its normal rapid-equilibrium random binding kinetics to some other mechanism by its coupling to oxidative phosphorylation.its coupling to oxidative phosphorylation.)
Bohanon 2017 Shock + (A complete understanding of the role of th … A complete understanding of the role of the liver in burn-induced hypermetabolism is lacking. We investigated the acute effect of severe burn trauma on liver mitochondrial respiratory capacity and coupling control as well as the signaling events underlying these alterations.Male BALB/c mice (8-12 weeks) received full-thickness scald burns on ∼30% of the body surface. Liver tissue was harvested 24 hours post injury. Mitochondrial respiration was determined by high-resolution respirometry. Citrate synthase activity was determined as a proxy of mitochondrial density. Male Sprague-Dawley rats received full-thickness scald burns to ∼60% of the body surface. Serum was collected 24 hours post injury. HepG2 cells were cultured with serum-enriched media from either sham or burn treated rats. Protein levels were analyzed via western blot.Mass-specific (p = 0.01) and mitochondrial-specific (p = 0.01) respiration coupled to ATP production significantly increased in the liver after burn. The respiratory control ratio for ADP (p = 0.04) and the mitochondrial flux control ratio (p = 0.03) were elevated in the liver of burned animals. Complex III and Complex IV protein abundance in the liver increased after burn by 17% and 14%, respectively. Exposure of HepG2 cells to serum from burned rats increased the pAMPKα:AMPKα ratio (p < 0.001) and levels of SIRT1 (p = 0.01), Nrf2 (p < 0.001), and PGC1α (p = 0.02).Severe burn trauma augments respiratory capacity and function of liver mitochondria, adaptations that augment ATP production. This response may be mediated by systemic factors that activate signaling proteins responsible for regulating cellular energy metabolism and mitochondrial biogenesis. energy metabolism and mitochondrial biogenesis.)
Racker 1971 J Biol Chem + (A complex was reconstituted with hydrophob … A complex was reconstituted with hydrophobic proteins from bovine heart mitochondrial membranes, cytochrome c, cytochrome oxidase, phospholipids, and coupling factors. These vesicular structures catalyzed oxidative phosphorylation with reduced N-methylphenazinium methyl sulfate as substrate.ylphenazinium methyl sulfate as substrate.)
Sobotka 2016 J Bioenerg Biomembr + (A compound with promising anticancer prope … A compound with promising anticancer properties, 3-bromopyruvate (3-BP) is a synthetic derivative of a pyruvate molecule; however, its toxicity in non-malignant cells has not yet been fully elucidated. Therefore, we elected to study the effects of 3-BP on primary hepatocytes in monolayer cultures, permeabilized hepatocytes and isolated mitochondria. After a 1-h treatment with 100 μM 3-BP cell viability of rat hepatocytes was decreased by 30 % as measured by the WST-1 test (p < 0.001); after 3-h exposure to ≥200 μM 3-BP lactate dehydrogenase leakage was increased (p < 0.001). Reactive oxygen species production was increased in the cell cultures after a 1-h treatment at concentrations ≥100 μmol/l (p < 0.01), and caspase 3 activity was increased after a 20-h incubation with 150 μM and 200 μM 3-BP (p < 0.001). This toxic effect of 3-BP was also proved using primary mouse hepatocytes. In isolated mitochondria, 3-BP induced a dose- and time-dependent decrease of mitochondrial membrane potential during a 10-min incubation both with Complex I substrates glutamate + malate or Complex II substrate succinate, although this decrease was more pronounced with the latter. We also measured the effect of 3-BP on respiration of isolated mitochondria. ADP-activated respiration was inhibited by 20 μM 3-BP within 10 min. Similar effects were also found in permeabilized hepatocytes of both species.so found in permeabilized hepatocytes of both species.)
Monaco 2018b Diabetologia + (A comprehensive assessment of skeletal mus … A comprehensive assessment of skeletal muscle ultrastructure and mitochondrial bioenergetics has not been undertaken in individuals with type 1 diabetes. This study aimed to systematically assess skeletal muscle mitochondrial phenotype in young adults with type 1 diabetes.Physically active, young adults (men and women) with type 1 diabetes (HbA1c 63.0 ± 16.0 mmol/mol [7.9% ± 1.5%]) and without type 1 diabetes (control), matched for sex, age, BMI and level of physical activity, were recruited (''n'' = 12/group) to undergo vastus lateralis muscle microbiopsies. Mitochondrial respiration (high-resolution respirometry), site-specific mitochondrial H2O2 emission and Ca2+ retention capacity (CRC) (spectrofluorometry) were assessed using permeabilised myofibre bundles. Electron microscopy and tomography were used to quantify mitochondrial content and investigate muscle ultrastructure. Skeletal muscle microvasculature was assessed by immunofluorescence.Mitochondrial oxidative capacity was significantly lower in participants with type 1 diabetes vs the control group, specifically at Complex II of the electron transport chain, without differences in mitochondrial content between groups. Muscles of those with type 1 diabetes also exhibited increased mitochondrial H2O2 emission at Complex III and decreased CRC relative to control individuals. Electron tomography revealed an increase in the size and number of autophagic remnants in the muscles of participants with type 1 diabetes. Despite this, levels of the autophagic regulatory protein, phosphorylated AMP-activated protein kinase (p-AMPKαThr172), and its downstream targets, phosphorylated Unc-51 like autophagy activating kinase 1 (p-ULK1Ser555) and p62, was similar between groups. In addition, no differences in muscle capillary density or platelet aggregation were observed between the groups.Alterations in mitochondrial ultrastructure and bioenergetics are evident within the skeletal muscle of active young adults with type 1 diabetes. It is yet to be elucidated whether more rigorous exercise may help to prevent skeletal muscle metabolic deficiencies in both active and inactive individuals with type 1 diabetes.rigorous exercise may help to prevent skeletal muscle metabolic deficiencies in both active and inactive individuals with type 1 diabetes.)
Metelkin 2009 FEBS J + (A computational model for the ATP-ADP stea … A computational model for the ATP-ADP steady-state exchange rate mediated by adenine nucleotide translocase (ANT) versus mitochondrial membrane potential dependence in isolated rat liver mitochondria is presented. The model represents the system of three ordinary differential equations, and the basic components included are ANT, F(0)/F(1)-ATPase, and the phosphate carrier. The model reproduces quantitatively the relationship between mitochondrial membrane potential and the ATP-ADP steady-state exchange rate mediated by the ANT operating in the forward mode, with the assumption that the phosphate carrier functions under rapid equilibrium. Furthermore, the model can simulate the kinetics of experimentally measured data on mitochondrial membrane potential titrated by an uncoupler. Verified predictions imply that the ADP influx rate is highly dependent on the mitochondrial membrane potential, and in the 0-100 mV range it is close to zero, owing to extremely low matrix ATP values. In addition to providing theoretical values of free matrix ATP and ADP, the model explains the diminished ADP-ATP exchange rate in the presence of nigericin, a condition in which there is hyperpolarization of the inner mitochondrial membrane at the expense of the mitochondrial Delta pH gradient; the latter parameter influences matrix inorganic phosphate and ATP concentrations in a manner also described.concentrations in a manner also described.)
Beard 2005 PLOS Comput Biol + (A computational model for the mitochondria … A computational model for the mitochondrial respiratory chain that appropriately balances mass, charge, and free energy transduction is introduced and analyzed based on a previously published set of data measured on isolated cardiac mitochondria. The basic components included in the model are the reactions at Complexes I, III, and IV of the electron transport system, ATP synthesis at F1FO ATPase, substrate transporters including adenine nucleotide translocase and the phosphate-hydrogen co-transporter, and cation fluxes across the inner membrane including fluxes through the K+/H+ antiporter and passive H+ and K+ permeation. Estimation of 16 adjustable parameter values is based on fitting model simulations to nine independent data curves. The identified model is further validated by comparison to additional datasets measured from mitochondria isolated from rat heart and liver and observed at low oxygen concentration. To obtain reasonable fits to the available data, it is necessary to incorporate inorganic-phosphate-dependent activation of the dehydrogenase activity and the electron transport system. Specifically, it is shown that a model incorporating phosphate-dependent activation of Complex III is able to reasonably reproduce the observed data. The resulting validated and verified model provides a foundation for building larger and more complex systems models and investigating complex physiological and pathophysiological interactions in cardiac energetics.stigating complex physiological and pathophysiological interactions in cardiac energetics.)
Wu 2007 J Biol Chem + (A computational model of mitochondrial met … A computational model of mitochondrial metabolism and electrophysiology is introduced and applied to analysis of data from isolated cardiac mitochondria and data on phosphate metabolites in striated muscle in vivo. This model is constructed based on detailed kinetics and thermodynamically balanced reaction mechanisms and a strict accounting of rapidly equilibrating biochemical species. Since building such a model requires introducing a large number of adjustable kinetic parameters, a correspondingly large amount of independent data from isolated mitochondria respiring on different substrates and subject to a variety of protocols is used to parameterize the model and ensure that it is challenged by a wide range of data corresponding to diverse conditions. The developed model is further validated by both in vitro data on isolated cardiac mitochondria and in vivo experimental measurements on human skeletal muscle. The validated model is used to predict the roles of NAD and ADP in regulating the tricarboxylic acid cycle dehydrogenase fluxes, demonstrating that NAD is the more important regulator. Further model predictions reveal that a decrease of cytosolic pH value results in decreases in mitochondrial membrane potential and a corresponding drop in the ability of the mitochondria to synthesize ATP at the hydrolysis potential required for cellular function. potential required for cellular function.)
Kaambre 2015 Abstract MiP2015 + (A considerable part of previous studies ab … A considerable part of previous studies about tumor bioenergetics were performed on several ''in vitro'' models with the conclusion that cancer cells present increased rates of glucose consumption and metabolize it to lactate even in the presence of O2 – a phenomenon called “Warburg effect”. ''In vitro'' studies cannot give the correct information about the functional activity and significance of OXPHOS versus glycolysis in malignancies and ignore host factors, which could exert significant effects. In our study we compare respiratory parameters of two very prevalent human tumors: breast cancer (HBC) and colorectal cancer (HCC).Primary tumor samples were provided by the Oncology and Hematology Clinic at the North Estonia Medical Centre and were analysed immediately after surgery. In this work we investigated mitochondrial respiration of tumor and control tissues ''in situ'' using the skinned sample technique [1,2]. Rates of O2 consumption were assayed at 25 °C by an Oxygraph-2k high-resolution respirometer (Oroboros Instruments, Innsbruck Austria). The solubility of oxygen at 25 °C was taken as 240 nmol/ml. All respiration rates were normalized per mg dry weight of tissue.Multiple substrate-inhibitor titration protocol was used for the measurement of respiratory capacities of different respiratory chain (RC) segments (Fig. 1). To analyze these changes, the respiration rates for different RC complexes and ratios of respiration rates for different substrates were calculated. The HBC is not accompanied with suppression of complex I-dependent respiration as it is shown in colorectal cancer.Apparent Michaelis-Menten constant (Km) and maximal rate of respiration (Vm) for ADP were calculated to characterize the affinity of mitochondria for exogenous ADP (permeability of mitochondrial outer membrane). Healthy colon tissue displayed low affinity for ADP (apparent Michaelis-Menten constant Km=256 ± 3 µM), whereas the affinity for ADP of tumor mitochondria (Km=93.6 ± 7.7 µM) and nearby tissue (junction area between cancer and normal mucosa) (Km=84.9 ± 9.9 µM) is significantly higher. Average Km value for HBC tissue samples was similar - 114.8±13.6 μM. Differences in Vmax correspond, to large extent, to the differences in number of mitochondria in these cell types. Measured rates of O2 consumption (normalized to Vm) were plotted vs. ADP concentration in medium as double reciprocal Lineweaver–Burk plots (Figure 2 A,B). This data is showing that formation of colorectal cancer is associated with relative changes in the activities of individual respiratory chain complexes which may be the result of mitochondrial DNA mutations and/or variations in the assembly of respiratory chain supercomplexes.Two subpopulations of mitochondria in HBC (Fig 2B) confirm the theory of two-compartment metabolism (“reversed Warburg”) proposed by several groups of cancer research [3,4]. During formation of HCC colon smooth muscle can participate in the carcinogenesis like energy reservoir and mitochondria lose the diffusion restrictions in the outer membrane. From all these results we can conclude that each type of cancer has its own special bioenergetic fingerprint.onclude that each type of cancer has its own special bioenergetic fingerprint.)
Hughey 2013 Thesis University of Calgary - Canada + (A constant provision of adenosine triphosp … A constant provision of adenosine triphosphate (ATP) is of necessity for cardiac contraction. If the heart progresses towards failure following a myocardial infarction (MI) it may undergo metabolic alterations that have the potential to compromise its ability to meet energetic demands. The main focus of this dissertation was to evaluate the efficacy of mesenchymal stem cell (MSC) transplantation to mitigate abnormalities in energy metabolism that contribute to ATP synthesis post-MI in the presence and absence of diet-induced insulin resistance. C57BL/6 mice were chow or high-fat fed prior to induction of a MI via chronic ligation of the left anterior descending coronary artery. Post-ligation, MSCs were transplanted via intramyocardial injection. Serial echocardiography was performed prior to and up to 28 days post-MI to evaluate cardiac systolic function. Hyperinsulinemic-euglycemic clamps coupled with the administration of isotopic tracers were employed post-MI to assess systemic insulin sensitivity and insulin-mediated, tissue-specific substrate uptake in the conscious, unrestrained mouse. High-resolution respirometry was utilized to evaluate cardiac mitochondrial function in saponinpermeabilized cardiac fibers. Western blotting was completed to assist in identifying molecular mechanisms through which the MSC therapy may modulate cardiac and systemic metabolic phenotypes. The improved systolic performance in MSC-treated mice was associated with a lessening of non-pathological ''in vivo'' insulin-stimulated cardiac glucose uptake. The changes in glucose uptake may have been via the MSC-mediated alterations in fatty acid availability/utilization. MSC therapy preserved fatty acid uptake in the absence of diet-induced insulin resistance. Conversely, the cell-based treatment reduced circulating nonesterified fatty acid concentration in high-fat fed mice. Additionally, potential impairments in insulin signalling may have been minimized as indicated by conservation of the p-Akt/Akt ratio. Down-stream of glucose uptake, the administration of MSCs conferred protective effects to mitochondrial oxidative phosphorylation efficiency, maximal function and mitochondrial content. Conclusions: The experiments conducted in this dissertation provide insight into the utility of MSC transplantation as a metabolic therapy for the metabolic perturbations that characterize insulin resistance in the infarcted heart. Also, these studies propose potential mechanisms of action that lead to an enhanced energetic and functional state in the infarcted heart following MSC transplantation.rcted heart following MSC transplantation.)
Seok 2013 Proc Natl Acad Sci U S A + (A cornerstone of modern biomedical researc … A cornerstone of modern biomedical research is the use of mouse models to explore basic pathophysiological mechanisms, evaluate new therapeutic approaches, and make go or no-go decisions to carry new drug candidates forward into clinical trials. Systematic studies evaluating how well murine models mimic human inflammatory diseases are nonexistent. Here, we show that, although acute inflammatory stresses from different etiologies result in highly similar genomic responses in humans, the responses in corresponding mouse models correlate poorly with the human conditions and also, one another. Among genes changed significantly in humans, the murine orthologs are close to random in matching their human counterparts (e.g., R(2) between 0.0 and 0.1). In addition to improvements in the current animal model systems, our study supports higher priority for translational medical research to focus on the more complex human conditions rather than relying on mouse models to study human inflammatory diseases.dels to study human inflammatory diseases.)
Logan 2018 Mol Metab + (A decline in mitochondrial function and bi … A decline in mitochondrial function and biogenesis as well as increased reactive oxygen species (ROS) are important determinants of aging. With advancing age, there is a concomitant reduction in circulating levels of insulin-like growth factor-1 (IGF-1) that is closely associated with neuronal aging and neurodegeneration. In this study, we investigated the effect of the decline in IGF-1 signaling with age on astrocyte mitochondrial metabolism and astrocyte function and its association with learning and memory.Learning and memory was assessed using the radial arm water maze in young and old mice as well as tamoxifen-inducible astrocyte-specific knockout of IGFR (GFAP-CreTAM/igfrf/f). The impact of IGF-1 signaling on mitochondrial function was evaluated using primary astrocyte cultures from igfrf/f mice using AAV-Cre mediated knockdown using Oroboros respirometry and Seahorse assays.Our results indicate that a reduction in IGF-1 receptor (IGFR) expression with age is associated with decline in hippocampal-dependent learning and increased gliosis. Astrocyte-specific knockout of IGFR also induced impairments in working memory. Using primary astrocyte cultures, we show that reducing IGF-1 signaling via a 30-50% reduction IGFR expression, comparable to the physiological changes in IGF-1 that occur with age, significantly impaired ATP synthesis. IGFR deficient astrocytes also displayed altered mitochondrial structure and function and increased mitochondrial ROS production associated with the induction of an antioxidant response. However, IGFR deficient astrocytes were more sensitive to H2O2-induced cytotoxicity. Moreover, IGFR deficient astrocytes also showed significantly impaired glucose and Aβ uptake, both critical functions of astrocytes in the brain.Regulation of astrocytic mitochondrial function and redox status by IGF-1 is essential to maintain astrocytic function and coordinate hippocampal-dependent spatial learning. Age-related astrocytic dysfunction caused by diminished IGF-1 signaling may contribute to the pathogenesis of Alzheimer's disease and other age-associated cognitive pathologies.Copyright © 2018 The Authors. Published by Elsevier GmbH. All rights reserved.cognitive pathologies. Copyright © 2018 The Authors. Published by Elsevier GmbH. All rights reserved.)
Elliehausen 2021 Exp Gerontol + (A decline in skeletal muscle mitochondrial … A decline in skeletal muscle mitochondrial function is associated with the loss of skeletal muscle size and function during knee osteoarthritis (OA). We have recently reported that 12-weeks of dietary rapamycin (Rap, 14 ppm), with or without metformin (Met, 1000 ppm), increased plasma glucose and OA severity in male Dunkin Hartley (DH) guinea pigs, a model of naturally occurring, age-related OA. The purpose of the current study was to determine if increased OA severity after dietary Rap and Rap+Met was accompanied by impaired skeletal muscle mitochondrial function. Mitochondrial respiration and hydrogen peroxide (H2O2) emissions were evaluated in permeabilized muscle fibers via high-resolution respirometry and fluorometry using either a saturating bolus or titration of ADP. Rap and Rap+Met decreased complex I (CI)-linked respiration and tended to increase ADP sensitivity, consistent with previous findings in patients with end-stage OA. The decrease in CI-linked respiration was accompanied with lower CI protein abundance. Rap and Rap+Met did not change mitochondrial H2O2 emissions. There were no differences between mitochondrial function in Rap versus Rap+Met suggesting that Rap was likely driving the change in mitochondrial function. This is the first inquiry into how lifespan extending treatments Rap and Rap+Met can influence skeletal muscle mitochondria in a model of age-related OA. Collectively, our data suggest that Rap with or without Met inhibits CI-linked capacity and increases ADP sensitivity in DH guinea pigs that have greater OA severity.ed capacity and increases ADP sensitivity in DH guinea pigs that have greater OA severity.)
Logan 2018 Thesis + (A decline in the oxygen cost of exercise e … A decline in the oxygen cost of exercise enhances exercise tolerance and performance. Substantial research has shown that dietary nitrate lowers the oxygen cost of exercise in sedentary humans; however, the metabolic determinants regarding how dietary nitrate influences oxygen consumption in skeletal muscle is not known. We addressed this gap in knowledge by employing a zebrafish (''Danio rerio'') model to study the effect of nitrate and nitrite supplementation. We hypothesize that zebrafish treated with nitrate and nitrite will respond with a decrease in oxygen consumption during exercise. We exposed zebrafish to 606.9 mg/L sodium nitrate (100 mg/L nitrate-nitrogen), 19.5 mg/L sodium nitrite (13 mg/liter nitrite-nitrogen), and control (no treatment) conditions. Using a Sievers Nitric Oxide Analyzer, we confirmed treatment by quantifying nitrate and nitrite levels in fish water before and after treatment, and in fish blood. We subjected these animals to a swim test to determine the effect of nitrate and nitrite treatment on oxygen consumption and found that nitrate exposure decreased, while nitrite exposure increased, the oxygen cost of exercise. To determine whether mitochondrial function could explain the differing effect of nitrate and nitrite on oxygen consumption, we isolated skeletal muscle mitochondria from each group and analyzed oxygen consumption using high resolution respirometry. Isolated mitochondria, exposed to various substrates of respiration exhibited no change in oxygen consumption, or ATP production during uncoupled states of respiration. We found no significant differences in the ratio of ADP:O, or mitochondrial proteins citrate synthase and ATP5A as a result of exposure. Future research will explore other aspects of energy metabolism and utilization to describe mechanisms that explain the differential oxygen consumption observed during nitrate and nitrite treatment.rved during nitrate and nitrite treatment.)
Kiss 2013 FASEB J + (A decline in α-ketoglutarate dehydrogenase … A decline in α-ketoglutarate dehydrogenase complex (KGDHC) activity has been associated with neurodegeneration. Provision of succinyl-CoA by KGDHC is essential for generation of matrix ATP (or GTP) by substrate-level phosphorylation catalyzed by succinyl-CoA ligase. Here, we demonstrate ATP consumption in respiration-impaired isolated and ''in situ'' neuronal somal mitochondria from transgenic mice with a deficiency of either dihydrolipoyl succinyltransferase (DLST) or dihydrolipoyl dehydrogenase (DLD) that exhibit a 20-48 % decrease in KGDHC activity. Import of ATP into the mitochondrial matrix of transgenic mice was attributed to a shift in the reversal potential of the adenine nucleotide translocase toward more negative values due to diminished matrix substrate-level phosphorylation, which causes the translocase to reverse prematurely. Immunoreactivity of all three subunits of succinyl-CoA ligase and maximal enzymatic activity were unaffected in transgenic mice as compared to wild-type littermates. Therefore, decreased matrix substrate-level phosphorylation was due to diminished provision of succinyl-CoA. These results were corroborated further by the finding that mitochondria from wild-type mice respiring on substrates supporting substrate-level phosphorylation exhibited ∼30 % higher ADP-ATP exchange rates compared to those obtained from DLST+/- or DLD+/- littermates. We propose that KGDHC-associated pathologies are a consequence of the inability of respiration-impaired mitochondria to rely on "in-house" mitochondrial ATP reserves. on "in-house" mitochondrial ATP reserves.)
Correa 2017 Crit Care + (A decrease in blood lactate levels (Lac) & … A decrease in blood lactate levels (Lac) >10% during the first hours of resuscitation in sepsis is associated with better outcomes, but the mechanisms are unclear. Our objective was to investigate the relationship between the time course of Lac, inflammatory response, and mitochondrial respiration during experimental sepsis.Original data from two previously published studies were reanalyzed. In cohort 1, pigs were randomized to be resuscitated for 48 h starting at 6, 12, and 24 h, respectively, after fecal peritonitis induction (n = 8 each). Animals were categorized according to the decrease in Lac during the first 6 h of resuscitation (early if ≥10% [Lac ≥10%] or late if <10% or increased [Lac <10%]), and systemic hemodynamics, inflammatory parameters, and mitochondrial function were compared between groups. In a second group of animals with fecal peritonitis and 24 h of resuscitation (n = 16, cohort 2), abdominal regional Lac exchange was measured, and animals were categorized according to the decrease in Lac as in cohort 1.Overall mortality was 20% (4 of 20) in the Lac ≥10% group and 60% (12 of 20) in the Lac <10% group (p = 0.022). In cohort 1, systemic hemodynamics were similar in the Lac ≥10% (n = 13) and Lac <10% (n = 11) groups. Plasma interleukin-6 levels increased during unresuscitated sepsis and decreased during resusciation in both groups, but they were lower at study end in the Lac ≥10% group (p = 0.047). Complexes I and II maximal (state 3) and resting (state 4) isolated brain mitochondrial respiration at study end was higher in the Lac ≥10% group than in the Lac <10% group, whereas hepatic, myocardial, and skeletal muscle mitochondrial respiration was similar in both groups. In cohort 2, mesenteric, total hepatic, and renal blood flow at study end was higher in the Lac ≥10% group (n = 7) than in the Lac <10% group (n = 9), despite similar cardiac output. Hepatic lactate influx and uptake in the Lac ≥10% group were approximately 1.5 and 3 times higher, respectively, than in the Lac <10% group (p = 0.066 for both).A decrease in Lac >10% during early resuscitation (6 h) after abdominal sepsis is associated with lower levels of plasma interleukin-6 and improved brain but not hepatic or muscle mitochondrial respiration. Blood flow redistribution to abdominal organs in animals with early decrease in Lac concentrations increases the potential to both deliver and extract Lac.ncentrations increases the potential to both deliver and extract Lac.)
Hervouet 2008 Carcinogenesis + (A decrease in oxidative phosphorylation (O … A decrease in oxidative phosphorylation (OXPHOS) is characteristic of many cancer types and, in particular, of clear cell renal carcinoma (CCRC) deficient in von Hippel–Lindau (''vhl'') gene. In the absence of functional pVHL, hypoxia-inducible factor (HIF) 1-α and HIF2-α subunits are stabilized, which induces the transcription of many genes including those involved in glycolysis and reactive oxygen species (ROS) metabolism. Transfection of these cells with ''vhl'' is known to restore HIF-α subunit degradation and to reduce glycolytic genes transcription. We show that such transfection with vhl of 786-0 CCRC (which are devoid of HIF1-α) also increased the content of respiratory chain subunits. However, the levels of most transcripts encoding OXPHOS subunits were not modified. Inhibition of HIF2-α synthesis by RNA interference in pVHL-deficient 786-0 CCRC also restored respiratory chain subunit content and clearly demonstrated a key role of HIF in OXPHOS regulation. In agreement with these observations, stabilization of HIF-α subunit by CoCl2 decreased respiratory chain subunit levels in CCRC cells expressing pVHL. In addition, HIF stimulated ROS production and mitochondrial manganese superoxide dismutase content. OXPHOS subunit content was also decreased by added H2O2. Interestingly, desferrioxamine (DFO) that also stabilized HIF did not decrease respiratory chain subunit level. While CoCl2 significantly stimulates ROS production, DFO is known to prevent hydroxyl radical production by inhibiting Fenton reactions. This indicates that the HIF-induced decrease in OXPHOS is at least in part mediated by hydroxyl radical production.IF-induced decrease in OXPHOS is at least in part mediated by hydroxyl radical production.)
Callaway 2013 Nature + (A dedicated website for sharing biology pa … A dedicated website for sharing biology papers before peer review leaves journals divided. What are biologists so afraid of? Physicists, mathematicians and social scientists routinely post their research to preprint servers such as arXiv.org before publication, yet few life scientists follow suit. A website that goes live this week is hoping to change that. The site, bioRχiv.org, launched by Cold Spring Harbor Laboratory Press in New York, bills itself as “the preprint server for biology”. It will operate similarly to arXiv, with scientists depositing papers as soon as they are ready to share them, weeks or months before formal publication.weeks or months before formal publication.)
Kula 2017 J Photochem Photobiol + (A density in algal suspension causes a sig … A density in algal suspension causes a significant change in the intensity and spectral composition of light reaching individual cells. Measurements of chlorophyll fluorescence allow us to observe any general changes in the bioenergetic status of photosynthesis. The aim of the study was to determine the effect of cultivation density on the PSII photochemical efficiency of three species of algae (Chlorella vulgaris, Botryococcus braunii and Chlorella emersonii), each with a different rate of growth - high, medium and low - respectively. The cell density of algae in suspension differentiated through the cultivation time (2, 4, and 8days) and the spectral composition of light. The results showed that the density of cultivation led to change in the photosynthetic apparatus of algae. The differences described between each day of cultivation (2, 4, and 8) in the kinetics of chlorophyll a fluorescence intensity in cells of the algal strains under study probably resulted from the different phases of growth of these cultures. In addition the results showed the beneficial effect of far red light on the photosynthetic apparatus and the growth of biomass in investigated algal strains. of biomass in investigated algal strains.)
Halangk 1997 Zentralbl Chir + (A disturbed energy metabolism in pancreati … A disturbed energy metabolism in pancreatic acinar cells is discussed as factor contributing to the development of acute pancreatitis (AP). In this study, we investigated to what extent the mitochondrial ATP producing capacity is impaired in the pancreatic tissue of rats with experimental AP. For preparation of mitochondria from rat pancreas, routine isolation procedures (tissue homogenization and differential centrifugation) were applied. Mitochondria were isolated from rats with edematous pancreatitis produced by hyperstimulation with caerulein, and from rats with mild necrotizing acute pancreatitis. The latter form of AP was induced by a temporary occlusion of the biliary pancreatic duct accompanied by a simultaneous intravenous injection of caerulein plus secretin and an intraabdominal administration of ethanol. As functional parameters of oxidative phosphorylation, the respiration rate, the mitochondrial membrane potential, and the activity of the complex I of the respiratory chain were determined. Mitochondria from rats with caerulein AP showed an enhanced respiration (61% vs. saline control) and a diminished membrane potential (-17 mV) if respiring with succinate in the non-phosphorylating state. This indicates an increased proton leak across the mitochondrial inner membrane. In the mild necrotizing AP, mitochondria were characterized by a decreased respiration with NAD(+)-linked substrates (-33% vs. sham-operated animals). This inhibition of respiration was confirmed by the reduced activity measured for the NADH-cytochrome c reductase (-32%). In both models of experimental AP the potency of mitochondria to produce ATP was significantly diminished. The stronger impairment of mitochondrial functions were found in the necrotizing form of AP. Reactive oxygen species may lead to the observed alterations--to the enhanced permeability of the mitochondrial inner membrane as well as to the inhibition of the complex I of the respiratory chain.of the complex I of the respiratory chain.)
Mizushima 2016 J Mol Cell Cardiol + (A failing heart shows severe energy insuff … A failing heart shows severe energy insufficiency, and it is presumed that this energy shortage plays a critical role in the development of cardiac dysfunction. However, little is known about the mechanisms that cause energy metabolic alterations in the failing heart. Here, we show that the novel RING-finger protein 207 (RNF207), which is specifically expressed in the heart, plays a role in cardiac energy metabolism. Depletion of RNF207 in neonatal rat cardiomyocytes (NRCs) leads to a reduced cellular concentration of adenosine triphosphate (ATP) and mitochondrial dysfunction. Consistent with this result, we observed here that the expression of RNF207 was significantly reduced in mice with common cardiac diseases including heart failure. Intriguingly, proteomic approaches revealed that RNF207 interacts with the voltage-dependent anion channel (VDAC), which is considered to be a key regulator of mitochondria function, as an RNF207-interacting protein. Our findings indicate that RNF207 is involved in ATP production by cardiomyocytes, suggesting that RNF207 plays an important role in the development of heart failure. role in the development of heart failure.)
Fridovich 1997 J Biol Chem + (A field of inquiry may be said to have com … A field of inquiry may be said to have come of age when conclusions initially viewed as remarkable or even unbelievable are accepted as commonplace. Study of the biology of the superoxide anion radical and of related free radicals, and the defenses thereto, has now reached this happy state of maturity. Superoxide and even hydroxyl radicals are now known to be produced in living systems, and elaborate systems of defense and repair, which minimize the ravages of these reactive species, have been described. New members of the superoxide dismutase, catalase, and peroxidase families of defensive enzymes are being found, as are new targets that are modified by O·̄2. In addition, the involvement of O·̄2 in both physiological and pathological processes is being established. A weighty tome would be needed to encompass a comprehensive coverage of this field of study. This review will describe only aspects of the biology of oxygen radicals that currently engage the interest of the writer. Hopefully they will also be of interest to the reader. Other recent reviews may serve to fill the gaps in this one.ws may serve to fill the gaps in this one.)
Klosterhoff 2017 Int J Biol Macromol + (A fraction composed of an arabinan-rich pe … A fraction composed of an arabinan-rich pectin was extracted from acerola fruit (''Malpighia emarginata'') and named ACWS. This fraction presented 93% of total carbohydrate, relative molecular weight of 7.5×104g/mol, galacturonic acid, arabinose, galactose, xylose and rhamnose in 52.1:32.4:7.2:4.8:3.5 molar ratio and had its structure confirmed by NMR analysis. The anti-fatigue activity of ACWS was evaluated using the weight load swim test on trained mice. ACWS was orally administered at doses of 50mg/kg, 100mg/kg and 200mg/kg for 28days. Plasma biochemical parameters, respiration of permeabilized skeletal muscle fibers, and GSH levels and lipoperoxidation in the brain (pre-frontal cortex, hippocampus, striatum and hypothalamus) were determined. ACWS could lengthen the swimming time, increase the plasma levels of glucose, triglycerides, lactate, and the GSH levels in the hippocampus at all tested doses. The mitochondrial respiratory capacity of the skeletal muscle was increased at middle and high ACWS doses. This study provides strong evidence that ''M. emarginata'' pectic polysaccharide supplementation has anti-fatigue activity, can modify the kinetics of energy substrates (carbohydrate and fat) mobilization and the respiratory capacity of the skeletal muscle, as well the antioxidant status in the hippocampus of ACWS treated animals.ant status in the hippocampus of ACWS treated animals.)
Ejarque 2018 Int J Obes (Lond) + (A functional population of adipocyte precu … A functional population of adipocyte precursors, termed adipose-derived stromal/stem cells (ASCs), is crucial for proper adipose tissue (AT) expansion, lipid handling, and prevention of lipotoxicity in response to chronic positive energy balance. We previously showed that obese human subjects contain a dysfunctional pool of ASCs. Elucidation of the mechanisms underlying abnormal ASC function might lead to therapeutic interventions for prevention of lipotoxicity by improving the adipogenic capacity of ASCs.Using epigenome-wide association studies, we explored the impact of obesity on the methylation signature of human ASCs and their differentiated counterparts. Mitochondrial phenotyping of lean and obese ASCs was performed. ''TBX15'' loss- and gain-of-function experiments were carried out and western blotting and electron microscopy studies of mitochondria were performed in white AT biopsies from lean and obese individuals.We found that DNA methylation in adipocyte precursors is significantly modified by the obese environment, and adipogenesis, inflammation, and immunosuppression were the most affected pathways. Also, we identified ''TBX15'' as one of the most differentially hypomethylated genes in obese ASCs, and genetic experiments revealed that ''TBX15'' is a regulator of mitochondrial mass in obese adipocytes. Accordingly, morphological analysis of AT from obese subjects showed an alteration of the mitochondrial network, with changes in mitochondrial shape and number.We identified a DNA methylation signature in adipocyte precursors associated with obesity, which has a significant impact on the metabolic phenotype of mature adipocytes. metabolic phenotype of mature adipocytes.)
Gasmi 2021 Arch Toxicol + (A fundamental metabolic feature of cancero … A fundamental metabolic feature of cancerous tissues is high glucose consumption. The rate of glucose consumption in a cancer cell can be 10-15 times higher than in normal cells. Isolation and cultivation of tumor cells in vitro highlight properties that are associated with intensive glucose utilization, the presence of minimal oxidative metabolism, an increase in lactate concentrations in the culture medium and a reduced rate of oxygen consumption. Although glycolysis is suggested as a general feature of malignant cells and recently identified as a possible contributing factor to tumor progression, several studies highlight distinct metabolic characteristics in some tumors, including a relative decrease in avidity compared to glucose and/or a glutamine dependency of lactate and even proliferative tumor cells. The aim of this review is to determine the particularities in the energy metabolism of cancer cells, focusing on the main nutritional substrates, such as glucose and glutamine, evaluating lactate dehydrogenase as a potential marker of malignancy and estimating activators and inhibitors in cancer treatment.vators and inhibitors in cancer treatment.)
Freyer 2012 Nat Genet + (A genetic bottleneck explains the marked c … A genetic bottleneck explains the marked changes in mitochondrial DNA (mtDNA) heteroplasmy that are observed during the transmission of pathogenic mutations, but the precise timing of these changes remains controversial, and it is not clear whether selection has a role. These issues are important for the genetic counseling of prospective mothers and for the development of treatments aimed at disease prevention. By studying mice transmitting a heteroplasmic single-base-pair deletion in the mitochondrial tRNA(Met) gene, we show that the extent of mammalian mtDNA heteroplasmy is principally determined prenatally within the developing female germline. Although we saw no evidence of mtDNA selection prenatally, skewed heteroplasmy levels were observed in the offspring of the next generation, consistent with purifying selection. High percentages of mtDNA genomes with the tRNA(Met) mutation were linked to a compensatory increase in overall mitochondrial RNA levels, ameliorating the biochemical phenotype and explaining why fecundity is not compromised.plaining why fecundity is not compromised.)
Chawla 2017 Nature + (A geneticist's decision not to publish his … A geneticist's decision not to publish his finalized preprint in a journal gets support from scientists online. Preprint papers posted on servers such as [[arXiv]] and [[bioRxiv]] are designed to get research results out for discussion before they are formally peer reviewed and published in journals. But for some scientists, the term is now a misnomer — their preprint papers will never be submitted for formal publication.never be submitted for formal publication.)
Munro 2022 Mitochondrion + (A greater capacity of endogenous matrix an … A greater capacity of endogenous matrix antioxidants has recently been hypothesized to characterize mitochondria of long-lived species, curbing bursts of reactive oxygen species (ROS) generated in this organelle. Evidence for this has been obtained from studies comparing the long-lived naked mole rat to laboratory mice. We tested this hypothesis by comparing the longest-lived metazoan, the marine bivalve ''Arctica islandica'' (MLSP=507 y), with shorter-lived and evolutionarily related species. We used a recently developed fluorescent technique to assess mantle and gill tissue mitochondria's capacity to consume hydrogen peroxide (H2O2) in multiple physiological states ''ex vivo''. Depending on the type of respiratory substrate provided, mitochondria of ''Arctica islandica'' could consume between 3-14 times more H2O2 than shorter-lived species. These findings support the contention that a greater capacity for the elimination of ROS characterizes long-lived species, a novel property of mitochondria thus far demonstrated in two key biogerontological models from distant evolutionary lineages.s far demonstrated in two key biogerontological models from distant evolutionary lineages.)
Goalstone 2010 Biochemical and Biophysical Research Communication + (A growing body of evidence implicates smal … A growing body of evidence implicates small G-proteins [e.g., Cdc42 and Rac1] in glucose-stimulated insulin secretion [GSIS] in the islet beta-cell. These signaling proteins undergo post-translational modifications [e.g., prenylation] at their C-terminal cysteine residue and appear to be essential for the transport and fusion of insulin-containing secretory granules with the plasma membrane and the exocytotic secretion of insulin. However, potential regulation of the prenylating enzymes by physiological insulin secretogues [e.g., glucose] has not been investigated thus far. Herein, we report immunological localization, sub-cellular distribution and regulation of farnesyltransferases [FTases] and geranylgeranyltransferase [GGTase] by glucose in insulin-secreting INS 832/13 beta-cells and normal rat islets. Our findings suggest that an insulinotropic concentration of glucose [20mM] markedly stimulated the expression of the alpha-subunits of FTase/GGTase-1, but not the beta-subunits of FTase or GGTase-1 without significantly affecting the predominantly cytosolic distribution of these holoenzymes in INS 832/13 cells and rodent islets. Under these conditions, glucose significantly stimulated [2.5- to 4.0-fold over basal] the activities of both FTase and GGTase-1 in both cell types. Together, these findings provide the first evidence to suggest that GSIS involves activation of the endogenous islet prenyltransferases by glucose, culminating in the activation of their respective G-protein substrates, which is necessary for cytoskeletal rearrangement, vesicular transport, fusion and secretion of insulin.ransport, fusion and secretion of insulin.)
Borutaite MiP2010 + (A growing body of evidence suggests that n … A growing body of evidence suggests that neurodegeneration in Alzheimer‘s disease (AD) is related to extracellular and intracellular accumulation of amyloid beta peptide (Aβ), mitochondrial dysfunction, increased neuronal loss, however the molecular pathways from Aβ to the main pathological hallmarks of AD are still elusive. Aβ molecules tend to aggregate and form complexes of varying size - from small soluble oligomers, bigger protofibrils and large insoluble fibrils. It is commonly assumed that formation of Aβ fibrils is the crucial event in the pathogenesis of AD. However, there is accumulating evidence that soluble oligomers are the most cytotoxic forms of Aβ though it is still unclear particles of which size and morphology exert most neurotoxicity. In our study we aimed to investigate a link between the size of soluble Aβ oligomers and their toxicity to rat cerebellar granule cells (CGC), cortical neurons and other non-neuronal cells. Variation in conditions during ''in vitro'' oligomerization of Aβ1-42 resulted in peptide assemblies with different particle size. Small oligomeric forms of Aβ1-42 with a particle z-height of 1-2 nm (as measured by atomic force microscopy) were found to be the most toxic species, inducing rapid neuronal necrosis at submicromolar concentrations, whereas the bigger aggregates (above 4-5 nm) did not cause detectable neuronal death. Aβ1-42 oligomers, monomers and fibrils were non-toxic to glial cells in CGC cultures or macrophage J774 cells. Small oligomers of Aβ exhibited tendency to bind to the phospholipid vesicles which composition was similar to reported neuronal plasma membrane composition. In contrast, bigger, non-toxic oligomers did not bind to phospholipid vesicles.We also found that mitochondrial respiratory functions were not affected by Aβ1-42 irrespective of the aggregate state: monomers, oligomers or fibrils of Aβ at concentrations up to 2 µM did not inhibit state 3 and state 4 respiration of isolated brain mitochondria and did not cause permeabilization of mitochondrial outer membrane as measured by the exogenous cytochrome c test on mitochondrial respiration. This suggests that Aβ1-42 at pathophysiologically relevant concentrations has no acute effect on mitochondria.In conclusion, our data demonstrate that small oligomers of Aβ at submicromolar concentrations induce rapid neuronal necrosis most likely due to the effect on neuronal plasma membranes, whereas bigger aggregates are not directly toxic to neurons.regates are not directly toxic to neurons.)
Mu 2022 Biochim Biophys Acta Mol Basis Dis + (A growing body of evidence supports a role … A growing body of evidence supports a role of the gut microbiota in regulating diverse physiological processes, including neural function and metabolism via the gut-brain axis. Infantile spasms syndrome is an early-onset epileptic encephalopathy associated with perturbed brain mitochondrial bioenergetics. Employing a neonatal rat model of infantile spasms, mitochondria respirometry and biochemical analyses, the present study reveals that gut microbiota manipulation by diet, antibiotics and probiotics have the potential to enhance hippocampal mitochondrial bioenergetics. Although preliminary in nature, our data reveal that microbial manipulation that regulates brain mitochondrial function may be a novel strategy for the treatment of epileptic disorders. for the treatment of epileptic disorders.)
Perry 2013 Diabetes + (A growing body of research is investigatin … A growing body of research is investigating the potential contribution of mitochondrial function to the etiology of type 2 diabetes. Numerous ''in vitro'', in situ, and ''in vivo'' methodologies are available to examine various aspects of mitochondrial function, each requiring an understanding of their principles, advantages, and limitations. This review provides investigators with a critical overview of the strengths, limitations and critical experimental parameters to consider when selecting and conducting studies on mitochondrial function. ''In vitro'' (isolated mitochondria) and in situ (permeabilized cells/tissue) approaches provide direct access to the mitochondria, allowing for study of mitochondrial bioenergetics and redox function under defined substrate conditions. Several experimental parameters must be tightly controlled, including assay media, temperature, oxygen concentration, and in the case of permeabilized skeletal muscle, the contractile state of the fibers. Recently developed technology now offers the opportunity to measure oxygen consumption in intact cultured cells. Magnetic resonance spectroscopy provides the most direct way of assessing mitochondrial function ''in vivo'' with interpretations based on specific modeling approaches. The continuing rapid evolution of these technologies offers new and exciting opportunities for deciphering the potential role of mitochondrial function in the etiology and treatment of diabetes.in the etiology and treatment of diabetes.)
Ludzki 2014 Thesis + (A hallmark of improved metabolic control i … A hallmark of improved metabolic control is a reduced free ADP requirement fora given workload (increased ADP sensitivity). In contrast to ''in vivo'' data, in situ assessments suggest that mitochondrial ADP sensitivity is decreased following exercise training, implying external regulat ion that is not recapitulated in situ. One previously unexplored regulator is palmitoyl-CoA (P-CoA), a lipid metabolism intermediate that inhibits the mitochondrial ADP transport protein adenine nucleotide transferase (ANT). This thesis: 1) established reduced mitochondrial ADP sensitivity following exercise trainingin middle aged males using permeabilized muscle fibre bundles (PmFB), 2) determined a methodology to evaluate ADP kinetics in PmFB in the presence of P-CoA, and 3) found increased mitochondrial ADP sensitivity in the presence of P-CoA following training. These data suggest that P- CoA is a key regulator of oxidative phosphorylation and direct future exploration of mitochondrial function towards the control of ADP transport via ANT and the effects of exercise on the P-CoA-ANT interaction. of exercise on the P-CoA-ANT interaction.)
Rowley 2017 J Nutr Biochem + (A hallmark of type 2 diabetes (T2D) is β-c … A hallmark of type 2 diabetes (T2D) is β-cell dysfunction and the eventual loss of functional β-cell mass. Therefore, mechanisms that improve or preserve β-cell function could be used to improve the quality of life of individuals with T2D. Studies have shown that monomeric, oligomeric and polymeric cocoa flavanols have different effects on obesity, insulin resistance and glucose tolerance. We hypothesized that these cocoa flavanols may have beneficial effects on β-cell function. INS-1 832/13-derived β-cells and primary rat islets cultured with a monomeric catechin-rich cocoa flavanol fraction demonstrated enhanced glucose-stimulated insulin secretion, while cells cultured with total cocoa extract and with oligomeric or polymeric procyanidin-rich fraction demonstrated no improvement. The increased glucose-stimulated insulin secretion in the presence of the monomeric catechin-rich fraction corresponded with enhanced mitochondrial respiration, suggesting improvements in β-cell fuel utilization. Mitochondrial complex III, IV and V components are up-regulated after culture with the monomer-rich fraction, corresponding with increased cellular ATP production. The monomer-rich fraction improved cellular redox state and increased glutathione concentration, which corresponds with nuclear factor, erythroid 2 like 2 (Nrf2) nuclear localization and expression of Nrf2 target genes including nuclear respiratory factor 1 (Nrf1) and GA binding protein transcription factor alpha subunit (GABPA), essential genes for increasing mitochondrial function. We propose a model by which monomeric cocoa catechins improve the cellular redox state, resulting in Nrf2 nuclear migration and up-regulation of genes critical for mitochondrial respiration, glucose-stimulated insulin secretion and ultimately improved β-cell function. These results suggest a mechanism by which monomeric cocoa catechins exert their effects as an effective complementary strategy to benefit T2D patients.Copyright © 2017 Elsevier Inc. All rights reserved. © 2017 Elsevier Inc. All rights reserved.)
Rowley 2017 Thesis + (A hallmark of type 2 diabetes (T2D) is β-c … A hallmark of type 2 diabetes (T2D) is β-cell dysfunction and the eventual loss of functional β-cell mass. Therefore, mechanisms that improve or preserve β-cell function could be used to improve the quality of life of individuals with T2D. Studies have shown that monomeric, oligomeric and polymeric cocoa flavanols have different effects on obesity, insulin resistance and glucose tolerance. We hypothesized that these cocoa flavanols may have beneficial effects on β-cell function. INS-1 832/13 derived β-cells and primary rat islets cultured with a monomeric catechin-rich cocoa flavanol fraction demonstrated enhanced glucose-stimulated insulin secretion, while cells cultured with total cocoa extract, oligomeric, or polymeric procyanidin-rich fractions demonstrated no improvement. The increased glucose-stimulated insulin secretion in the presence of the monomeric catechin-rich fraction corresponded with enhanced mitochondrial respiration, suggesting improvements in β-cell fuel utilization. Mitochondrial complex III, IV and V components were upregulated after culture with the monomer-rich fraction, corresponding with increased cellular ATP production. The monomer-rich fraction improved cellular redox state and increased glutathione concentration, which corresponds with Nrf2 nuclear localization and expression of Nrf2 target genes, including NRF-1 and GABPA, essential genes for increasing mitochondrial function. We propose a model by which monomeric cocoa catechins improve the cellular redox state, resulting in Nrf2 nuclear migration and upregulation of genes critical for mitochondrial respiration, and, ultimately, enhanced glucose-stimulated insulin secretion and β-cell function. These results suggest a mechanism by which monomeric cocoa catechins exert their effects as an effective complementary strategy to benefit T2D patients.ementary strategy to benefit T2D patients.)
Hoeks 2008 FEBS Lett + (A high intake of dietary fat has been sugg … A high intake of dietary fat has been suggested to diminish mitochondrial functioning in skeletal muscle, possibly attributing to muscular fat accumulation. Here we show however, that an 8-week high-fat dietary intervention did not affect intrinsic functioning of rat skeletal muscle mitochondria assessed by respirometry, neither on a carbohydrate- nor on a lipid-substrate. Interestingly, PPARGC1A protein increased by approximately 2-fold upon high-fat feeding and we observed inconsistent results on different markers of mitochondrial density. Mitochondrial ROS production, assessed by electron spin resonance spectroscopy remained unaffected. Intramyocellular lipid levels increased significantly illustrating that a reduced innate mitochondrial function is not a prerequisite for intra-muscular fat accumulation.isite for intra-muscular fat accumulation.)
Park 2017 Metab Brain Dis + (A high-fat diet induces obesity in mice, l … A high-fat diet induces obesity in mice, leading to insulin resistance, decreased mitochondrial function, and increased apoptosis in the hippocampus, which eventually result in memory loss. The present study investigated the effect of physical exercise on memory, hippocampal mitochondrial function, and apoptosis in mice with in insulin resistance caused by obesity due to high-fat diet. Mice were randomly divided into four groups: control (CON), control and exercise (CON + EX), high fat diet (HFD), and high fat diet and exercise (HFD + EX). After receiving a high-fat (60%) diet for 20 weeks to induce obesity, the animals were subjected to an exercise routine 6 times per week, for 12 weeks. The exercise duration and intensity gradually increased over 4-week intervals. Hippocampal memory was examined using the step-down avoidance task. Mitochondrial function and apoptosis were also examined in the hippocampus and dentate gyrus. We found that obesity owing to a high-fat diet induced insulin resistance and caused a decrease in memory function. Insulin resistance also caused a decrease in mitochondrial function in the hippocampus by reducing Ca2+ retention and O2, respiration, increasing the levels of H2O2, and Cyp-D, and mPTP opening. In addition, apoptosis in the hippocampus increased owing to decreased expression of Bcl-2 and increased expression of Bax, cytochrome c, and caspase-3 and TUNEL-positive cells. In contrast, physical exercise led to reduced insulin resistance, improved mitochondrial function, and reduced apoptosis in the hippocampus. The results suggest that physiological stimulations such as exercise improve hippocampal function and suppress apoptosis, potentially preventing the memory loss associated with obesity-induced insulin resistance.potentially preventing the memory loss associated with obesity-induced insulin resistance.)
Kwon 2009 Thesis + (A high-fat diet leads to an accumulation o … A high-fat diet leads to an accumulation of lipid in skeletal muscle, and the development of both mitochondrial dysfunction and insulin resistance. Recently, our lab reported that lipid overload leads to elevated H2O2 emission from muscle mitochondria, and that mitochondrial-targeted scavenging of H2O2 completely prevents the development of high fat diet-induced insulin resistance. These findings raise the possibility that interventions which acutely restore cellular metabolic balance in muscle may also acutely restore insulin sensitivity. We hypothesized that mitochondrial function and insulin sensitivity can be restored in skeletal muscle of high-fat fed rats by creating an acute deficit in metabolic balance via 2 h low-intensity treadmill exercise or 16 h fasting. Male Sprague-Dawley rats (125-150g) were either maintained on a standard high carbohydrate- diet or fed a high-fat (60%) diet for 6 weeks and divided into three groups the day before the study: one group was maintained on the normal high-fat diet, another group was fasted overnight (16 h), and a third group completed a single 2 h bout of low-intensity treadmill exercise (10 m/min) and then were given normal overnight ad libitum access to the high-fat diet. Oral glucose tolerance tests were administrated to assess insulin action. Red gastrocnemius muscles were harvested and permeabilized fibers prepared for determination of mitochondrial respiratory function and H2O2 emission. A single 16 h fast significantly (P<0.05) improved insulin sensitivity in rats maintained on a high-fat diet (P<0.05). Oxygen consumption rate in permeabilized fibers in response to submaximal and maximal ADP concentration when supported exclusively with complex I substrates were not different among groups. However, when respiration was supported by fatty acids (palmitoylcarnitine plus malate, complex I + II substrates), high-fat diet plus exercise group showed higher (P<0.05) rates compared with high-fat diet group. There were no significant differences in H2O2 emission among the 4 groups. In conclusion, a single 16 h overnight fast is sufficient to restore insulin sensitivity in high fat diet-induced insulin resistant rats, providing evidence that insulin action in muscle is acutely sensitive to the metabolic state of cells. A single bout of low-intensity treadmill exercise in high-fat fed rats failed to restore insulin action but increased ADP-stimulated respiratory capacity, providing evidence of an as yet unidentified regulatory mechanism of the respiratory system. Somewhat surprisingly however, neither fasting nor exercise altered the H2O2 emitting potential in permeabilized fibers, suggesting that further work is required to better understand the factors influencing mitochondrial function and their potential link to insulin sensitivity.lized fibers, suggesting that further work is required to better understand the factors influencing mitochondrial function and their potential link to insulin sensitivity.)
Cavadas 2015 Hum Mutat + (A high-resolution mtDNA phylogenetic tree … A high-resolution mtDNA phylogenetic tree allowed us to look backward in time to investigate purifying selection. Purifying selection was very strong in the last 2,500 years, continuously eliminating pathogenic mutations back until the end of the Younger Dryas (∼11,000 years ago), when a large population expansion likely relaxed selection pressure. This was preceded by a phase of stable selection until another relaxation occurred in the out-of-Africa migration. Demography and selection are closely related: expansions led to relaxation of selection and higher pathogenicity mutations significantly decreased the growth of descendants. The only detectible positive selection was the recurrence of highly pathogenic nonsynonymous mutations (m.3394T>C-m.3397A>G-m.3398T>C) at interior branches of the tree, preventing the formation of a dinucleotide STR (TATATA) in the MT-ND1 gene. At the most recent time scale in 124 mother-children transmissions, purifying selection was detectable through the loss of mtDNA variants with high predicted pathogenicity. A few haplogroup-defining sites were also heteroplasmic, agreeing with a significant propensity in 349 positions in the phylogenetic tree to revert back to the ancestral variant. This nonrandom mutation property explains the observation of heteroplasmic mutations at some haplogroup-defining sites in sequencing datasets, which may not indicate poor quality as has been claimed.© 2015 WILEY PERIODICALS, INC.s has been claimed. © 2015 WILEY PERIODICALS, INC.)
Djafarzadeh 2017 J Vis Exp + (A high-resolution oxygraph is a device for … A high-resolution oxygraph is a device for measuring cellular oxygen consumption in a closed-chamber system with very high resolution and sensitivity in biological samples (intact and permeabilized cells, tissues or isolated mitochondria). The high-resolution oxygraph device is equipped with two chambers and uses polarographic oxygen sensors to measure oxygen concentration and calculate oxygen consumption within each chamber. Oxygen consumption rates are calculated using software and expressed as picomoles per second per number of cells. Each high-resolution oxygraph chamber contains a stopper with injection ports, which makes it ideal for substrate-uncoupler-inhibitor titrations or detergent titration protocols for determining effective and optimum concentrations for plasma membrane permeabilization. The technique can be applied to measure respiration in a wide range of cell types and also provides information on mitochondrial quality and integrity, and maximal mitochondrial respiratory electron transport system capacity.ratory electron transport system capacity.)
Hatefi 1961 Biochim Biophys Acta + (A highly active DPNH-cytochrome c reductas … A highly active DPNH-cytochrome c reductase has been isolated from beef-heart mitochondria. The best preparations of the enzyme catalyze the reduction by DPNH of approx. 50–60 μmoles cytochrome c/min/mg protein at 38°. The enzymic activity is completely inhibited by Amytal, p-chloromercuriphenyl sulfonate, antimycin A, SN-5949 or 2-nonyl-4-hydroxyquinoline-N-oxide, and is stimulated by EDTA. The preparation contains DPNH flavoprotein, cytochromes b and c1, Coenzyme Q and non-heme iron and is essentially free of succinic-cytochrome c reductase as well as cytochrome oxidase activity.se as well as cytochrome oxidase activity.)
Kotarsky 2010 Mitochondrion + (A homozygous mutation in the complex III c … A homozygous mutation in the complex III chaperone BCS1L causes GRACILE syndrome (intrauterine growth restriction, aminoaciduria, cholestasis, hepatic iron overload, lactacidosis). In control and patient fibroblasts we localized BCS1L in inner mitochondrial membranes. In patient liver, kidney, and heart BCS1L and Rieske protein levels, as well as the amount and activity of complex III, were decreased. Major histopathology was found in kidney and liver with cirrhosis and iron deposition, but of iron-related proteins only ferritin levels were high. In placenta from a GRACILE fetus, the ferrooxidases ceruloplasmin and hephaestin were upregulated suggesting association between iron overload and placental dysfunction.n iron overload and placental dysfunction.)
Stodden 2020 Proc Natl Acad Sci U S A + (A key component of scientific communicatio … A key component of scientific communication is sufficient information for other researchers in the field to reproduce published findings. For computational and data-enabled research, this has often been interpreted to mean making available the raw data from which results were generated, the computer code that generated the findings, and any additional information needed such as workflows and input parameters. Many journals are revising author guidelines to include data and code availability. This work evaluates the effectiveness of journal policy that requires the data and code necessary for reproducibility be made available postpublication by the authors upon request. We assess the effectiveness of such a policy by (i) requesting data and code from authors and (ii) attempting replication of the published findings. We chose a random sample of 204 scientific papers published in the journal Science after the implementation of their policy in February 2011. We found that we were able to obtain artifacts from 44 % of our sample and were able to reproduce the findings for 26 %. We find this policy—author remission of data and code postpublication upon request—an improvement over no policy, but currently insufficient for reproducibility.urrently insufficient for reproducibility.)
Nissen 2017 Glia + (A key enzyme in brain glutamate homeostasi … A key enzyme in brain glutamate homeostasis is glutamate dehydrogenase (GDH) which links carbohydrate and amino acid metabolism mediating glutamate degradation to CO2 and expanding tricarboxylic acid (TCA) cycle capacity with intermediates, i.e. anaplerosis. Humans express two GDH isoforms, GDH1 and 2, whereas most other mammals express only GDH1. hGDH1 is widely expressed in human brain while hGDH2 is confined to astrocytes. The two isoforms display different enzymatic properties and the nature of these supports that hGDH2 expression in astrocytes potentially increases glutamate oxidation and supports the TCA cycle during energy-demanding processes such as high intensity glutamatergic signaling. However, little is known about how expression of hGDH2 affects the handling of glutamate and TCA cycle metabolism in astrocytes. Therefore, we cultured astrocytes from cerebral cortical tissue of hGDH2-expressing transgenic mice. We measured glutamate uptake and metabolism using [3 H]glutamate, while the effect on metabolic pathways of glutamate and glucose was evaluated by use of 13 C and 14 C substrates and analysis by mass spectrometry and determination of radioactively labeled metabolites including CO2 , respectively. We conclude that hGDH2 expression increases capacity for uptake and oxidative metabolism of glutamate, particularly during increased workload and aglycemia. Additionally, hGDH2 expression increased utilization of branched-chain amino acids (BCAA) during aglycemia and caused a general decrease in oxidative glucose metabolism. We speculate, that expression of hGDH2 allows astrocytes to spare glucose and utilize BCAAs during substrate shortages. These findings support the proposed role of hGDH2 in astrocytes as an important fail-safe during situations of intense glutamatergic activity.uations of intense glutamatergic activity.)
Andziak 2006 Aging Cell + (A key tenet of the oxidative stress theory … A key tenet of the oxidative stress theory of aging is that levels of accrued oxidative damage increase with age. Differences in damage generation and accumulation therefore may underlie the natural variation in species longevity. We compared age-related profiles of whole-organism lipid peroxidation (urinary isoprostanes) and liver lipid damage (malondialdehyde) in long living naked mole-rats [maximum lifespan (MLS) > 28.3 years] and shorter-living CB6F1 hybrid mice (MLS approximately 3.5 years). In addition, we compared age-associated changes in liver non-heme iron to assess how intracellular conditions, which may modulate oxidative processes, are affected by aging. Surprisingly, even at a young age, concentrations of both markers of lipid peroxidation, as well as of iron, were at least twofold (P < 0.005) greater in naked mole tats than in mice. This refutes the hypothesis that prolonged naked mole-rat longevity is due to superior protection against oxidative stress. The age-related profiles of all three parameters were distinctly species specific. Rates of lipid damage generation in mice were maintained throughout adulthood, while accrued damage in old animals was twice that of young mice. In naked mole-rats, urinary isoprostane excretion declined by half with age (P < 0.001), despite increases in tissue iron (P < 0.05). Contrary to the predictions of the oxidative stress theory, lipid damage levels did not change with age in mole-rats. These data suggest that the patterns of age-related changes in levels of markers of oxidative stress are species specific, and that the pronounced longevity of naked mole-rats is independent of oxidative stress parameters.le-rats is independent of oxidative stress parameters.)
Cottingham 1983 Biochim Biophys Acta + (A kinetic analysis of oxygen uptake was ca … A kinetic analysis of oxygen uptake was carried out in order to investigate the role of ubiquinone pool behaviour in plant mitochondria. The interaction of the external NADH dehydrogenase with either the cytochrome system or the cyanide-insensitive oxidase was examined under various conditions. The involvement of a ubiquinone pool can be deduced from the shape of the titration curve as the appropriate oxidase system is inhibited, by antimycin A for the cytochrome system and salicylhydroxamic acid for the cyanide-insensitive oxidase, at different activities of the NADH dehydrogenase. In the absence of a specific inhibitor, the turnover of the external NADH dehydrogenase was adjusted using a novel NADH-generating system involving the recycling of a low concentration of NAD+ by added glucose 6-phosphate dehydrogenase in the presence of substrate. The results show that ubiquinone pool behaviour is observed between the external NADH dehydrogenase and either the cytochrome b-c1 complex or the cyanide-insensitive oxidase. However, there is a substantial departure from pool behaviour during the simultaneous operation of both oxidases.e simultaneous operation of both oxidases.)
Laner 2017 Abstract EUROMIT2017 Cologne + (A lack of physical activity associates wit … A lack of physical activity associates with decreased mitochondrial capacity and is a major cause underlying metabolic dysregulation and preventable diseases in modern societies. In contrast, an active lifestyle supports enhanced mitochondrial capacities and reduces the risk of degenerative diseases. Despite this well-known relation between health and mitochondrial function, there is no regimented, quantitative system, or database organised to routinely test, compare and monitor mitochondrial capacities within individuals or populations. Every study of mitochondrial (mt) function and disease in human tissues and cells is faced with Evolution, Age, Gender, Lifestyle and Environment ([[EAGLE]]) as essential background conditions characterizing the individual patient, subject, study group, species, tissue or – to some extent - cell line. Only a large and well-coordinated network can manage to generate the necessary number of consistent data to address the complexity of EAGLE. Using [[high-resolution respirometry]], the [[K-Regio MitoFit]] and [[MitoEAGLE]] initiatives develop novel lab standards and diagnostic methods for monitoring of a mitochondrial fitness score. SOPs are elaborated for sample preparation, respiratory evaluation and data documentation. Fresh and cryopreserved cells obtained non-invasively from blood samples broaden the scope for respirometric mitochondrial diagnosis.for respirometric mitochondrial diagnosis.)
Gnaiger 2016 Abstract EBEC Riva del Garda 2016 + (A lack of physical activity associates wit … A lack of physical activity associates with decreased mitochondrial capacity and is a major cause underlying metabolic dysregulation and preventable diseases in modern societies. In contrast, an active lifestyle supports enhanced mitochondrial capacities and reduces the risk of degenerative diseases. Despite this well-known relation between health and mitochondrial function, there is no regimented, quantitative system, or database organised to routinely test, compare and monitor mitochondrial capacities within individuals or populations. Using high-resolution respirometry, the MitoFit and MitoEAGLE initiatives will develop novel lab standards and diagnostic methods for the monitoring of a mitochondrial fitness score. To this end, SOPs will be worked out regarding sample preparation, respiratory evaluation and data documentation. Fresh and cryopreserved cells obtained noninvasively from blood samples will serve as models, the latter allowing samples to be collected for later analysis, thereby broadening the scope for respirometric investigations.This approach will then be expanded to all sorts of human tissues and cells of interest and assess aspects relating to Evolution, Age, Gender, Lifestyle and Environment (EAGLE) as essential background conditions characterizing the individual patient, subject, study group, and/or species. The huge scope of this endeavour requires an international network of laboratories capable of generating the necessary number of consistent data to address the complexity of EAGLE. Coping with the mass of the expected data necessitates a dedicated MitoEAGLE knowledge management network developing harmonization protocols towards generating a rigorously monitored data repository on mitochondrial respiratory function. The resulting MitoEAGLE data management system will enable to interrelate results of a large number of studies, to interpret pathological phenotypes, and to set results into the multidimensional context of EAGLE.nto the multidimensional context of EAGLE.)
Lukasiak 2016 Eur J Pharmacol + (A large conductance potassium (BKCa) chann … A large conductance potassium (BKCa) channel opener, NS1619 (1,3-dihydro-1- [2-hydroxy-5-(trifluoromethyl) phenyl]-5-(trifluoromethyl)-2H-benzimidazole-2-one), is well known for its protective effects against ischemia-reperfusion injury; however, the exact mode of its action remains unclear. The aim of this study was to characterize the effect of NS1619 on endothelial cells. The endothelial cell line EA.hy926, guinea pig hearts and submitochondrial particles isolated from the heart were used. In the isolated guinea pig hearts, which were perfused using the Langendorff technique, NS1619 caused a dose-dependent increase in coronary flow that was inhibited by L-NAME. In EA.hy926 cells, NS1619 also caused a dose-dependent increase in the intracellular calcium ion concentration [Ca(2+)]i, as measured using the FURA-2 fluorescent probe. Moreover, NS1619 decreased the oxygen consumption rate in EA.hy926 cells, as assessed using a Clark-type oxygen electrode. However, when NS1619 was applied in the presence of oligomycin, the oxygen consumption increased. NS1619 also decreased the mitochondrial membrane potential, as measured using a JC-1 fluorescent probe in the presence and absence of oligomycin. Additionally, the application of NS1619 to submitochondrial particles inhibited ATP synthase. In summary, NS1619 has pleiotropic actions on EA.hy926 cells and acts not only as an opener of the BKCa channel in EA.hy926 cells but also as an inhibitor of the respiratory chain component, sarcoplasmic reticulum ATPase, which leads to the release of Ca(2+) from the endoplasmic reticulum. Furthermore, NS1619 has the oligomycin-like property of inhibiting mitochondrial ATP synthase.Copyright © 2016 Elsevier B.V. All rights reserved. © 2016 Elsevier B.V. All rights reserved.)
Sperl 1994 J Inher Metab Dis + (A large number of enzyme systems are exami … A large number of enzyme systems are examined for the diagnosis of mitochondrial myopathies including the pyruvate dehidrogenase complex, tricarboxylic-acid-cycle enzymes and respiratory chain complexes. This investigation can be carried out in frozen tissue. For the study of oxidative phosphorilation in intact mitochondria, fresh muscle tissue is required, and isolation of mitochondria from large amounts of tissue (at least 500-1000 mg) is necessary. For ethical reason this imposes a serious limitation, especially in paediatric patients. Radiochemical measurements of oxidation rates in various substrates in 600 g supernatant from 100-300 mg amounts of muscle tissue has partly overcome this problem. (Bookelman ''et.al''., 1978). Owing to the low yield, the danger of selective isolation of different mitochondrial populations exists. In addition, since isolated mitochondria removed from their natural environment are more or less unstable, there is a possibility of artefacts. Recently, investigation of saponin-skinned muscle fibers by polarographic methods was reported for cardiac (Veksler ''et. al''., 1987) and human muscle tissue. In such permeabilized fibers, study of mitochondrial respiratory control is possible as in isolated mitochondria but without the disadvantages mentioned above (Letellier ''et.al''., 1992; Kunz ''et.al''., 1993).We investigated saponin-skinned muscle fibers in three patients suspected of a mitochondrial encephalo-myopathy. For our studies we used a specially developed respirometer with a sensitivity ten times higher than the established instruments (Kunz ''et.al''., 1993).ished instruments (Kunz ''et.al''., 1993).)
Lauterbach 2013 FEBS J + (A large number of industrially relevant en … A large number of industrially relevant enzymes depend upon nicotinamide cofactors, which are too expensive to be added in stoichiometric amounts. Existing NAD(P)H-recycling systems suffer from low activity, or the generation of side products. H₂-driven cofactor regeneration has the advantage of 100% atom efficiency and the use of H₂ as a cheap reducing agent, in a world where sustainable energy carriers are increasingly attractive. The state of development of H₂-driven cofactor-recycling systems and examples of their integration with enzyme reactions are summarized in this article. The O₂-tolerant NAD⁺-reducing hydrogenase from Ralstonia eutropha is a particularly attractive candidate for this approach, and we therefore discuss its catalytic properties that are relevant for technical applications.t are relevant for technical applications.)
Santoso 2019 Bioorg Med Chem + (A library of thirty-two quinolinequinones … A library of thirty-two quinolinequinones (QQs) with various amine substituents at the 6- and 7-positions were synthesised efficiently and in good yields for evaluation as potential anti-tuberculosis agents. ''Mycobacterium tuberculosis'' growth inhibition assays demonstrated that QQs bearing moderate length alkyl chains (i.e. heptylphenylamino- and octylamino-QQs), and aryl groups (i.e. phenylethylamino- and benzylamino-QQs) exhibited encouraging inhibitory activity, while QQ analogue 7-chloro-6-propargylamino-quinoline-5,8-dione (16b) had excellent inhibitory activity (MIC = 8 μM). The cLogP values and redox activities of the QQs were determined, and neither readout correlated with the anti-mycobacterial activities of the compounds. Notwithstanding, mode of action studies of 16b revealed that treatment of ''M. tuberculosis'' with this compound led to activation of NADH-dependent oxygen consumption suggesting a redox cycling mechanism. To this end, the promising anti-mycobacterial activity of several QQs and their ability to perturb oxygen management leading to an uncontrolled respiratory burst, as identified in this work and by others, demonstrates the merit of further optimising the anti-mycobacterial activity of this readily synthesised class of compound.Copyright © 2019. Published by Elsevier Ltd.right © 2019. Published by Elsevier Ltd.)
Antonenko 2011 J Biol Chem + (A limited decrease in mitochondrial membra … A limited decrease in mitochondrial membrane potential can be beneficial for cells, especially under some pathological conditions, suggesting that mild uncouplers (protonophores) causing such an effect are promising candidates for therapeutic uses. The great majority of protonophores are weak acids capable of permeating across membranes in their neutral and anionic forms. In the present study, protonophorous activity of a series of derivatives of cationic rhodamine 19, including dodecylrhodamine (C(12)R1) and its conjugate with plastoquinone (SkQR1), was revealed using a variety of assays. Derivatives of rhodamine B, lacking dissociable protons, showed no protonophorous properties. In planar bilayer lipid membranes, separating two compartments differing in pH, diffusion potential of H(+) ions was generated in the presence of C(12)R1 and SkQR1. These compounds induced pH equilibration in liposomes loaded with the pH probe pyranine. C(12)R1 and SkQR1 partially stimulated respiration of rat liver mitochondria in State 4 and decreased their membrane potential. Also, C(12)R1 partially stimulated respiration of yeast cells but, unlike the anionic protonophore FCCP, did not suppress their growth. Loss of function of mitochondrial DNA in yeast (grande-petite transformation) is known to cause a major decrease in the mitochondrial membrane potential. We found that petite yeast cells are relatively more sensitive to the anionic uncouplers than to C(12)R1 compared with grande cells. Together, our data suggest that rhodamine 19-based cationic protonophores are self-limiting; their uncoupling activity is maximal at high membrane potential, but the activity decreases membrane potentials, which causes partial efflux of the uncouplers from mitochondria and, hence, prevents further membrane potential decrease.vents further membrane potential decrease.)
Bergeson 1981 West J Med + (A major international movement is in progr … A major international movement is in progress to extend metrication using the International System of Units. Significantly involved is the field of medicine. Extensive changes adopted abroad now appear in foreign medical literature, and physicians in the United States commonly are unprepared to interpret medical information from abroad because the data are reported in unfamiliar terms. The system has broad immediate and future implications to American physicians.uture implications to American physicians.)
Fernandes 2012 Am J Hum Genet + (A major unanswered question regarding the … A major unanswered question regarding the dispersal of modern humans around the world concerns the geographical site of the first human steps outside of Africa. The "southern coastal route" model predicts that the early stages of the dispersal took place when people crossed the Red Sea to southern Arabia, but genetic evidence has hitherto been tenuous. We have addressed this question by analyzing the three minor west-Eurasian haplogroups, N1, N2, and X. These lineages branch directly from the first non-African founder node, the root of haplogroup N, and coalesce to the time of the first successful movement of modern humans out of Africa, ∼60 thousand years (ka) ago. We sequenced complete mtDNA genomes from 85 Southwest Asian samples carrying these haplogroups and compared them with a database of 300 European examples. The results show that these minor haplogroups have a relict distribution that suggests an ancient ancestry within the Arabian Peninsula, and they most likely spread from the Gulf Oasis region toward the Near East and Europe during the pluvial period 55-24 ka ago. This pattern suggests that Arabia was indeed the first staging post in the spread of modern humans around the world.Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.shed by Elsevier Inc. All rights reserved.)
Friedrich 2010 Abstract MiP2010 + (A medium of containing high levels of pota … A medium of containing high levels of potassium chloride (KCl) is commonly used when assessing respiratory function of isolated mitochondria from various tissues. However, the measured intracellular [K+] in kidney proximal tubular cells is about 60 mM and in cardiac myocytes approximately 130 mM. Therefore, the use of a similar media [K+] for all tissues seems unsupported. Here we investigated the effect of different [K+] on respiratory function in mitochondria isolated from kidney cortex and heart of healthy male Sprague-Dawley rats.Oxygen consumptions and the respiratory control ratios (RCR) were measured using respiratory medias containing [K+] of 15, 37, 81, 111 and 146 mM. In all measurements, the media contained (in mM): 1 EGTA, 20 HEPES, 5 MgCl2, 5 KPO4- and 1 g/l bovine serum albumin. pH was adjusted to 7.4 and the osmolarity to 330 mosm/kg HK2O using a 1:3 ratio of sucrose and mannitol.The RCR of kidney cortex mitochondria decreased when the [K+] was elevated compared to the media containing 15 mM K+ (5.2±0.2 vs. 2.5±0.2, 3.7±0.2, 3.9±0.2, 3.0±0.1, respectively). However, RCR of heart mitochondria was lowest at 37 mM (3.9±0.3) and was highest at 146 mM K+ (10.1±0.45). A two-way ANOVA showed that kidney cortex mitochondria have a different sensitivity towards K+ compared to heart mitochondria (interaction P<0.05, treatment P<0.05, group P<0.05). Glibenclamide (100 µM), an inhibitor of the ATP-sensitive K+ channel, increased RCR in kidney cortex mitochondria at 15 mM K+ (+32%), but significantly more at 146 mM K+ (+47%). Blockade of the voltage-gated K+ channel by 4-aminopyridine (4-AP, 1 mM) together with glibenclamide improved RCR by +73% at 146 mM K+. Neither of the applied K+-channel blockers had any effect on the RCR of heart mitochondria. Mitochondria swelling at increasing [K+] were observed in kidney cortex mitochondria, measured as loss of absorbance at 540 nm.Kidney cortex mitochondria in K+-based media are non-functional in [K+] ranging from 37-146 mM. Heart mitochondria do not display K+-sensitivity to the same degree, but rather increase respiratory function with increasing [K+]. Furthermore, we demonstrated that a tissue specific difference in mitochondria K+-channels may explain these differences. The present study therefore demonstrates the importance of choosing a correct ''in vitro media'' to ensure a high quality of mitochondria research.urthermore, we demonstrated that a tissue specific difference in mitochondria K+-channels may explain these differences. The present study therefore demonstrates the importance of choosing a correct ''in vitro media'' to ensure a high quality of mitochondria research.)
Lyon 2006 Anal Chem + (A method for low-level, low-potential elec … A method for low-level, low-potential electrochemical detection of hydrogen peroxide using a chemically activated redox mediator is presented. This method is unique in that it utilizes a mediator, Amplex Red, which is only redox-active when chemically oxidized by H2O2 in the presence of the enzyme horseradish peroxidase (HRP). When employed in concert with microelectrode square wave voltammetry to optimize sensing at ultralow concentrations (<1 microM), this method exhibits marked improvements in analytical sensitivity and detection limits (limit of detection as low as 8 pM) over existing protocols. Sensing schemes incorporating both freely diffusing and immobilized HRP are evaluated, and the resulting analytical sensitivities are 1.22 +/- 0.04 and (2.1 +/- 0.6) x 10(-1) microA/(microM mm2), respectively, for peroxide concentrations in the high picomolar to low micromolar range. A second linear region exists for lower peroxide concentrations. Furthermore, quantitative enzyme kinetics analysis using Michaelis-Menten parameters is possible through interpretation of data collected in this scheme. Km values for soluble and immobilized HRP were 84 +/- 13 and 504 +/- 19 microM, respectively. This method is amenable to any biological detection scheme that generates hydrogen peroxide as a reactive product.ates hydrogen peroxide as a reactive product.)
Cheng 2017 US Patent + (A method for treating a microbial infection in a subject includes administering to the subject a pharmaceutical composition which has a therapeutically effective amount of an antimicrobial peptide containing a derivative of P-113.)
Lee 2010 Curr Biol + (A mild inhibition of mitochondrial respira … A mild inhibition of mitochondrial respiration extends the life span of many organisms, including yeast, worms, flies, and mice, but the underlying mechanism is unknown. One environmental condition that reduces rates of respiration is hypoxia (low oxygen). Thus, it is possible that mechanisms that sense oxygen play a role in the longevity response to reduced respiration. The hypoxia-inducible factor HIF-1 is a highly conserved transcription factor that activates genes that promote survival during hypoxia. In this study, we show that inhibition of respiration in C. elegans can promote longevity by activating HIF-1. Through genome-wide screening, we found that RNA interference (RNAi) knockdown of many genes encoding respiratory-chain components induced hif-1-dependent transcription. Moreover, HIF-1 was required for the extended life spans of clk-1 and isp-1 mutants, which have reduced rates of respiration. Inhibiting respiration appears to activate HIF-1 by elevating the level of reactive oxygen species (ROS). We found that ROS are increased in respiration mutants and that mild increases in ROS can stimulate HIF-1 to activate gene expression and promote longevity. In this way, HIF-1 appears to link respiratory stress in the mitochondria to a nuclear transcriptional response that promotes longevity.iptional response that promotes longevity.)
Zelenka 2015 Oxid Med Cell Longev + (A moderate elevation of reactive oxygen sp … A moderate elevation of reactive oxygen species (ROS) production and a mild inhibition of mitochondrial respiratory chain have been associated with a health promotion and a lifespan extension in several animal models of aging. Here, we tested whether this phenomenon called mitohormesis could be mediated by L-lactate. The treatment with 5 mM L-lactate significantly increased H2O2 production and slightly inhibited the respiration in cultured skin fibroblasts and in isolated mitochondria. The L-lactate exposure was associated with oxidation of intracellular glutathione, phosphorylation of 5'AMP-activated protein kinase (AMPK), and induction of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α) transcription. A replicative aging of fibroblasts (L0) with a constant (LC), or intermittent 5 mM L-lactate (LI) in media showed that the high-passage LI fibroblasts have higher respiration, lower H2O2 release, and lower secretion of L-lactate compared to L0 and LC. This protection against mitochondrial dysfunction in LI cells was associated with lower activity of mechanistic target of rapamycin complex 1 (mTORC1), less signs of cellular senescence, and increased autophagy compared to L0 and LC. In conclusion, we demonstrated that intermittent but not constant exposure to L-lactate triggers mitohormesis, prevents aging-associated mitochondrial dysfunction, and improves other markers of aging. prevents aging-associated mitochondrial dysfunction, and improves other markers of aging.)
Lee 2019 Nat Metab + (A moderate reduction of body temperature c … A moderate reduction of body temperature can induce a remarkable lifespan extension. Here we examine the link between cold temperature, germ line fitness and organismal longevity. We show that low temperature reduces age-associated exhaustion of germ stem cells (GSCs) in ''Caenorhabditis elegans'', a process modulated by thermosensory neurons. Notably, robust self-renewal of adult GSCs delays reproductive aging and is required for extended lifespan at cold temperatures. These cells release prostaglandin E2 (PGE2) to induce cbs-1 expression in the intestine, increasing somatic production of hydrogen sulfide (H2S), a gaseous signaling molecule that prolongs lifespan. Whereas loss of adult GSCs reduces intestinal cbs-1 expression and cold-induced longevity, application of exogenous PGE2 rescues these phenotypes. Importantly, tissue-specific intestinal overexpression of cbs-1 mimics cold-temperature conditions and extends longevity even at warm temperatures. Thus, our results indicate that GSCs communicate with somatic tissues to coordinate extended reproductive capacity with longevity.nded reproductive capacity with longevity.)
Heidler 2013 Abstract MiP2013 + (A morphological hallmark of the failing hu … A morphological hallmark of the failing human heart is a devastative autophagic degradation of cellular structures starting from the perinuclear region, proposed to actively shift the heart into a decompensated state [1]. We studied heart samples from different species, i.e. a mouse model of cardiac specific expression of MCP1 that autonomously develops heart failure [2], hibernating Syrian hamsters [3] and a pig model of mitochondrial dysfunction exposed to hyperbaric oxygen.Our data reveal an age-dependent increase of perinuclear degradation in mouse hearts that occurred prior to the onset of cardiac dysfunction. These center core-like lesions in the myofibrillar compartment are most likely the end-stage result of a vicious cycle that starts with a physiological response to lowered levels of cardiac workload. Accordingly we found that in hibernating Syrian hamsters under conditions of depressed metabolism interfibrillar mitochondria are reversibly silenced whilst subsarcolemmal mitochondria remain more active. Central remodeling of cardiomyocyte compartments is a phenomenon primarily known in the hibernating myocardium [4]. Here we show in pig hearts that the isolated impairment of the interfibrillary compartment can be fully re-activated upon treatment with hyperbaric oxygen.We conclude that differential compartment regulation by switching the activity status of mitochondrial sub-populations from on to off and vice versa might provide a hitherto unnoticed flexible on-demand plasticity in cardiomyocytes. Such alterations make proper myofibril contraction in the silenced compartment unlikely. Silenced mitochondria can be re-activated on demand. Only long-lasting mitochondrial silencing, e.g. upon chronic cardiac overload, might increase the risk of adverse cardiomyocyte remodeling. risk of adverse cardiomyocyte remodeling.)
Canton 1995 Biochem J + (A new criterion is utilized for the interp … A new criterion is utilized for the interpretation of flow-force relationships in rat liver mitochondria. The criterion is based on the view that the nature of the relationship between the H+/O ratio and the membrane potential can be inferred from the relationship between ohmic-uncoupler-induced extra respiration and the membrane potential. Thus a linear relationship between extra respiration and membrane potential indicates unequivocally the independence of the H+/O ratio from the membrane potential and the leak nature of the resting respiration [Brand, Chien, and Diolez (1994) Biochem. J. 297, 27-29]. On the other hand, a non-linear relationship indicates that the H+/O ratio is dependent on the membrane potential. The experimental assessment of this relationship in the presence of an additional ohmic leak, however, is rendered difficult by both the uncoupler-induced depression of membrane potential and the limited range of dependence of the H+/O ratio on the membrane potential. We have selected conditions, i.e. incubation of mitochondria at low temperatures, where the extent of non-linearity is markedly increased. It appears that the nature of the resting respiration of mitochondria in vitro is markedly dependent on the temperature: at low temperatures the percentage of resting respiration due to membrane leak decreases and that due to intrinsic uncoupling of the proton pumps increases. uncoupling of the proton pumps increases.)
Chinopoulos 2009 + (A novel method exploiting the differential … A novel method exploiting the differential affinity of ADP and ATP to Mg(2+) was developed to measure mitochondrial ADP-ATP exchange rate. The rate of ATP appearing in the medium after addition of ADP to energized mitochondria, is calculated from the measured rate of change in free extramitochondrial [Mg2+] reported by the membrane-impermeable 5K+ salt of the Mg2+-sensitive fluorescent indicator, Magnesium Green, using standard binding equations. The assay is designed such that the adenine nucleotide translocase (ANT) is the sole mediator of changes in [Mg2+] in the extramitochondrial volume, as a result of ADP-ATP exchange. We also provide data on the dependence of ATP efflux rate within the 6.8-7.8 matrix pH range as a function of membrane potential. Finally, by comparing the ATP-ADP steady-state exchange rate to the amount of the ANT in rat brain synaptic, brain nonsynaptic, heart and liver mitochondria, we provide molecular turnover numbers for the known ANT isotypes. and liver mitochondria, we provide molecular turnover numbers for the known ANT isotypes.)
Sjoevall 2015 US Patent + (A novel method useful in drug screening. T … A novel method useful in drug screening. The method is useful for testing effects of substances on the mitochondria, notably toxic or beneficial effects of drug substances or candidate drug substances. The method is based on measurement in live human mitochondria ''ex vivo'', but in a setting as near the ''in vivo'' situation as possible. The method is also useful for testing substances impact on the mitochondrial respiration. The method can be used to i) screening and selection of early or late stage drug candidates in cells derived from blood from healthy individuals or in so-called buffy coat, which is a concentrated solution of platelets and white blood cells, ii) testing a patient's sensitivity to a known mitochondrial toxicant, iii) analysing mitochondrial drug toxicity in clinical trials, and/or iv) analysing beneficial effects of drugs intended to improve mitochondrial function.ntended to improve mitochondrial function.)
Farrar 2015 US Patent + (A nucleic acid sequence encoding the yeast … A nucleic acid sequence encoding the yeast NDI1 protein of SEQ ID NO: 542 or a functional variant thereof having at least 90% sequence identity with SEQ ID NO: 2 is described. The nucleic acid sequence comprises at least 50 codons which are codon optimised compared with the sequence of yeast NDI1 gene of SEQ ID NO: 1. An immune optimised functional variant of the yeast NDI1 protein of SEQ ID NO: 542 having at least 90% sequence identity with SEQ ID NO: 542 is also described, and includes at least one amino acid change selected from the group consisting of L194F, K283E, K9R, S142N, L501M, L402I, A386S, S85K, F89H, L93M, K195E, L18M, K213E, K372E, L258F, K510E, L158M, R478Q, L482M. K372E, L258F, K510E, L158M, R478Q, L482M.)
Bentinger 2007 Mitochondrion + (A number of functions for coenzyme Q (CoQ) … A number of functions for coenzyme Q (CoQ) have been established during the years but its role as an effective antioxidant of the cellular membranes remains of dominating interest. This compound is our only endogenously synthesized lipid soluble antioxidant, present in all membranes and exceeding both in amount and efficiency that of other antioxidants. The protective effect is extended to lipids, proteins and DNA mainly because of its close localization to the oxidative events and the effective regeneration by continuous reduction at all locations. Its biosynthesis is influenced by nuclear receptors which may give the possibility, in the future, by using agonists or antagonists, of reestablishing the normal level in deficiencies caused by genetic mutations, aging or cardiomyopathy. An increase in CoQ concentration in specific cellular compartments in the presence of various types of oxidative stress appears to be of considerable interest.ss appears to be of considerable interest.)
Bastow 2016 J Cell Sci + (A number of genes have been linked to fami … A number of genes have been linked to familial forms of the fatal motor neuron disease amyotrophic lateral sclerosis (ALS). Over 150 mutations within the gene encoding superoxide dismutase 1 (SOD1) have been implicated in ALS, but why such mutations lead to ALS-associated cellular dysfunction is unclear. In this study, we identify how ALS-linked SOD1 mutations lead to changes in the cellular health of the yeast ''Saccharomyces cerevisiae''. We find that it is not the accumulation of aggregates but the loss of Sod1 protein stability that drives cellular dysfunction. The toxic effect of Sod1 instability does not correlate with a loss of mitochondrial function or increased production of reactive oxygen species, but instead prevents acidification of the vacuole, perturbs metabolic regulation and promotes senescence. Central to the toxic gain-of-function seen with the SOD1 mutants examined was an inability to regulate amino acid biosynthesis. We also report that leucine supplementation results in an improvement in motor function in a ''Caenorhabditis elegans'' model of ALS. Our data suggest that metabolic dysfunction plays an important role in Sod1-mediated toxicity in both the yeast and worm models of ALS.© 2016. Published by The Company of Biologists Ltd.ublished by The Company of Biologists Ltd.)
Ruiz-Pesini 2004 Science + (A phylogenetic analysis of 1125 global hum … A phylogenetic analysis of 1125 global human mitochondrial DNA (mtDNA) sequences permitted positioning of all nucleotide substitutions according to their order of occurrence. The relative frequency and amino acid conservation of internal branch replacement mutations was found to increase from tropical Africa to temperate Europe and arctic northeastern Siberia. Particularly highly conserved amino acid substitutions were found at the roots of multiple mtDNA lineages from higher latitudes. These same lineages correlate with increased propensity for energy deficiency diseases as well as longevity. Thus, specific mtDNA replacement mutations permitted our ancestors to adapt to more northern climates, and these same variants are influencing our health today.variants are influencing our health today.)
Berg 2016 Science + (A preprint is a complete scientific manusc … A preprint is a complete scientific manuscript (often one also being submitted to a peer-reviewed journal) that is uploaded by the authors to a public server without formal review. After a brief inspection to ensure that the work is scientific in nature, the posted scientific manuscript can be viewed without charge on the Web.Conclusions: Preprints could play important roles in accelerating scientific progress; they could serve the needs and foster the careers of scientists; and, in cooperation with existing journals, they could enhance the current system for communicating results and ideas in the life sciences. However, preprints are relatively new to biology, and many questions remain unanswered. Will funding agencies encourage the use of preprint servers? Will all journals accept manuscripts for publication after they have been disseminated as preprints? Will the life sciences community find ways to make biology preprints easily discoverable? And will researchers themselves decide to submit, cite, and evaluate work presented in preprint form? The cooperative spirit displayed by the attendees at ASAPbio gives hope that these complex issues, as well as others that limit the communication of scientific ideas and results, can be addressed in a productive and thoughtful manner.sed in a productive and thoughtful manner.)
Committee 2018 COPE Discussion Document + (A preprint is a scholarly manuscript poste … A preprint is a scholarly manuscript posted by the author(s) in an openly accessible platform, usually before or in parallel with the peer review process. While the sharing of manuscripts via preprint platforms has been common in some disciplines (such as physics and mathematics) for many years, uptake in other disciplines traditionally had been low, possibly influenced by differences in research culture and strong opposition by some journal publishers [1]. The landscape has evolved rapidly in other fields in recent years, however, thanks to the launch of additional, discipline-specific preprint platforms and increased support by funders and initiatives such as ASAPBio[2, 3].ers and initiatives such as ASAPBio[2, 3].)
Gnaiger 1991 Soc Exp Biol Seminar Series + (A previous critique of the term facultative invertebrate anaerobiosis focused on the duration of anoxia. An addition, important, yet much neglected aspect is dicussed here, namely the extent and quantification of the 'anaerobic' condition.)
Podrabsky 2000 Am J Physiol Regul Integr Comp Physiol + (A previous phylogenetic analysis among 15 … A previous phylogenetic analysis among 15 taxa of the teleost fish ''Fundulus'' suggested that there should be thermal-adaptive differences in heart metabolism among populations. To test this hypothesis, the rate of oxygen consumption and the activities of all 11 glycolytic enzymes were measured in isolated heart ventricle from two populations of ''Fundulus heteroclitus''. Heart ventricular metabolism is greater in a northern population versus a southern population of these fish. Analysis of the amount of glycolytic enzymes indicates that 87% of the variation in cardiac metabolism within and between populations is explained by the variation in three enzymes (pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, and lactate dehydrogenase). These enzymes are the same three enzymes that were predicted to be important based on previously determined phylogenetic patterns of expression. Our data indicate that near-equilibrium enzymes, as well as classically defined rate-limiting enzymes, can also influence metabolism.ng enzymes, can also influence metabolism.)
Gurakan 1990 Thermochim Acta + (A procedure has been developed for the pre … A procedure has been developed for the preparation of microbial biomass of standard, defined quality suitable for the determination of elemental composition and enthalpy of combustion. Furthermore methods for the determination of residual moisture and ash content of biomass samples have been established. The results indicate that samples should be prepared in a freeze-dried (lyophilized) state and that residual moisture content should be determined immediately prior to sample preparation for combustion calorimetry and elemental analysis. Results from such analysis should then be related to material which is first freeze- dried and subsequently oven dried (100 °C for 24 hours) as reference state. The method outlined here for microbial biomass should prove suitable for biological samples from a wide variety of sources including both pure proteins, fats etc. as well as cells and tissues.s, fats etc. as well as cells and tissues.)
Bradford 1976 Anal Biochem + (A protein determination method which invol … A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls. eliminated by the use of proper controls.)
Lam 1967 Arch Biochem Biophys + (A protein factor, designated as Factor B, … A protein factor, designated as Factor B, was extracted from lyophilized acetone-washed bovine heart mitochondria and purified by ammonium sulfate fractionation, and ion-exchange chromatography on DEAE-cellulose and CM-cellulose. Centrifugation in a sucrose density gradient showed that the activity of the purified factor was closely associated with a symmetrical protein peak comprising approximately 70% of the protein. Its molecular weight was estimated to be 32,000, using hemoglobin and cytochrome c as markers. Factor B produces several-fold stimulation of ATP-driven NAD reduction, and of net phosphorylation coupled to NADH or succinate oxidation in ammonia particles. The stimulation of ATP-driven NAD reduction activity exceeds that given by an optimal amount of oligomycin, and in the presence of a saturation level of Factor B, oligomycin stimulation disappears. Also, Factor B stimulation is evident in urea-depleted particles which have been supplemented by Factor A. These particles show no stimulation by oligomycin. The results suggest that Factor B may participate in the energy transfer reactions between the respiratory chain and the terminal step resulting in ATP synthesis. terminal step resulting in ATP synthesis.)
Wijermars 2016 Am J Transplant + (A recent seminal paper implicated ischemia … A recent seminal paper implicated ischemia-related succinate accumulation followed by succinate driven-reactive oxygen species formation as key driver of ischemia reperfusion injury. Although the data show that the mechanism is universal for all organs tested (kidney, liver, heart and brain), a remaining question is to what extend these observations for mouse translate to man. We here show that succinate accumulation is not a universal event during ischemia, and does not occur during renal graft procurement, in fact tissue succinate content progressively decreases with advancing graft ischemia time (p<0.007). Contrasting responses were also found with respect to mitochondrial susceptibility towards ischemia and reperfusion, with rodent mitochondria robustly resistant towards warm ischemia, but human and pig mitochondria being highly susceptible to warm ischemia (p<0.05). These observations suggest that succinate-driven reactive oxygen formation does not occur in the context of kidney transplantation. In fact absent allantoin release from the reperfused grafts suggests minimal oxidative stress during clinical reperfusion.This article is protected by copyright. All rights reserved. is protected by copyright. All rights reserved.)
Tomporowski 2003 Acta Psychol (Amst) + (A review was conducted of studies that ass … A review was conducted of studies that assessed the effects of acute bouts of physical activity on adults' cognitive performance. Three groups of studies were constituted on the basis of the type of exercise protocol employed. Each group was then evaluated in terms of information-processing theory. It was concluded that submaximal aerobic exercise performed for periods up to 60 min facilitate specific aspects of information processing; however, extended exercise that leads to dehydration compromises both information processing and memory functions. The selective effects of exercise on cognitive performance are explained in terms of Sanders' [Acta Psychol. 53 (1983) 61] cognitive-energetic model.. 53 (1983) 61] cognitive-energetic model.)
Meunier 1995 Biochemistry + (A screen has been performed of possible in … A screen has been performed of possible inhibitors of the quinol oxidation sites of the two terminal oxidases of ''Escherichia coli'', cytochromes bo and bd. Aurachin C and its analogues were found to be particularly effective inhibitors of both enzymes, whereas aurachin D and its analogues displayed a selectivity for inhibition of cytochrome bd. In addition, a tridecyl derivative of stigmatellin was found to inhibit cytochrome bo at concentrations which were without significant effect on cytochrome bd. Titration of membrane-bound cytochromes bo and bd with aurachin C gave an observed dissociation constant in the range of 10-8 M. A similar observed dissociation constant was determined for aurachin D inhibition of cytochrome bd. For both enzymes, their kinetic behavior during a series of substrate pulses indicates that it is reduction of the enzyme by quinol, and not reaction with oxygen, which is inhibited. It is concluded that the aurachins are powerful inhibitors of the quinol oxidation sites of bacterial cytochromes bo and bd. The effects of aurachin C on cytochrome bo were investigated in more detail. The number of inhibitor binding sites on the purified enzyme was determined by titration to be 0.6 per enzyme. At an inhibitorloxidase ratio of 1.0, electron donation into the enzyme from added quinol is extremely slow, making it very unlikely that there is more than one quinone-reactive site. Aurachin C caused a potent inhibition of electron donation from a pulse of quinol. In contrast, it was without effect on cyanide or carbon monoxide binding to the reduced enzyme, on cyanide binding to the oxidized enzyme, on the optical spectra of the heme groups, or on the kinetics of oxygen reduction after photolysis of carbon monoxide from the reduced enzyme. We conclude that binding of aurachin C specifically inhibits the quinol oxidation site and does not directly affect the properties of the binuclear center.irectly affect the properties of the binuclear center.)
Bers 1982 Am J Physiol + (A simple method for the accurate determina … A simple method for the accurate determination of free [Ca] in ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA)-buffered Ca solutions is described. This method is useful for calibration of Ca macro- and microelectrodes to low free [Ca] and should improve the reliability of calculated free [Ca] in more complex solutions. Briefly, free [Ca] in Ca-EGTA solutions is measured with a Ca electrode, bound Ca is calculated, and Scatchard and double-reciprocal plots are resolved for the total [EGTA] and the apparent Ca-EGTA association constant (K'Ca) in the solutions used. The free [Ca] is then recalculated using the determined parameters, giving a more accurate knowledge of the free [Ca] in these solutions and providing an accurate calibration curve for the Ca electrode. These solutions can then be used to calibrate other Ca electrodes (e.g., Ca microelectrodes) or the calibrated Ca electrode can be used to measure free [Ca] in solutions containing multiple metal ligands. This method allows determination of free [Ca], K'Ca, and total [EGTA] in the actual solutions used regardless of pH, temperature, or ionic strength. It does not require accurate knowledge of K'Ca or EGTA purity and circumvents many potential errors due to assumption of binding parameters. K'Ca was found to be 2.45 +/- 0.04 X 10(6) M-1 in 100 mM KCl, 10 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid, and 1 mM EGTA at pH 7.00 and 23 degrees C. Total [EGTA] varied with supplier but was always less than quoted. supplier but was always less than quoted.)
Stokich 2014 Cryobiology + (A simple method to cryogenically preserve … A simple method to cryogenically preserve hepatocyte monolayers is currently not available but such a technique would facilitate numerous applications in the field of biomedical engineering, cell line development, and drug screening. We investigated the effect of trehalose and dimethyl sulfoxide (Me2SO) in cryopreservation of human hepatocellular carcinoma (HepG2) cells in suspension and monolayer formats. HepG2 cell monolayers were incubated for 24 h at varying concentrations of trehalose (50-150 mM) prior to cryopreservation to identify the optimum concentration for such preincubation. When trehalose alone was used as the cryoprotective agent (CPA), cells in monolayer format did not survive freezing while cells in suspension demonstrated 14% viability 24 h after thawing. Only 6-13% of cells in monolayers survived freezing in cell culture medium supplemented with 10% Me2SO, but 42% of cells were recovered successfully if monolayers were preincubated with 100 mM trehalose prior to freezing in the Me2SO supplemented medium. Interestingly, for cells frozen in suspension in presence of 10% Me2SO, metabolic activity immediately following thawing did not change appreciably compared to unfrozen control cells. Finally, Raman spectroscopy techniques were employed to evaluate ice crystallization in the presence and absence of trehalose in freezing solutions without cells because crystallization may alter the extent of injury observed in cell monolayers. We speculate that biomimetic approaches of using protective sugars to preserve cells in monolayer format will facilitate the development of techniques for long-term preservation of human tissues and organs in the future.of human tissues and organs in the future.)
Small 1985 Biochem J + (A simple spectrophotometric assay was deve … A simple spectrophotometric assay was developed for peroxisomal fatty [[acyl-CoA oxidase]] activity. The assay, based on the H2O2-dependent oxidation of leuco-dichlorofluorescein catalysed by exogenous [[peroxidase]], is more sensitive than methods previously described. By using mouse liver samples, cofactor requirements were assessed and a linear relationship was demonstrated between dye oxidation and enzyme concentration. By using this assay on subcellular fractions, palmitoyl-CoA oxidase activity was localized for the first time in microperoxisomes of rat intestine. The assay was also adapted to measure D-amino acid oxidase activity, demonstrating the versatility of this method for measuring activity of other H2O2-producing oxidases.g activity of other H2O2-producing oxidases.)
Petrova 2014 Proc Chem + (A simple, accurate and rapid voltammetric … A simple, accurate and rapid voltammetric method has been developed for the quantitative determination of coenzyme Q10. Studies with direct current voltammetry were carried out using a glassy carbon electrode (GCE) in a phosphate buffer solution (pH 6.86). A well-defined oxidation peak of CoQ10 was obtained at -0.600 V vs Ag/AgCl. The magnitude of the oxidation peak current has been found to be related to the concentration of the coenzyme over the range of (2·10-5 to 2·10-4 M) (''r'' = 0.991). Antioxidant activity of CoQ10 was investigated.) (''r'' = 0.991). Antioxidant activity of CoQ10 was investigated.)
Lin 2012 FASEB J + (A single high-fat meal acutely increases s … A single high-fat meal acutely increases skeletal muscle mitochondrial H2O2 emitting potential (mEH2O2), shifts the intracellular redox environment to a more oxidized state, and increases circulating markers of oxidative stress. Bioenergetically, this implies an acute lipid load may elevate the reducing pressure/membrane potential ({Delta}{Psi}m) within mitochondria and, conversely, that even a mild increase in energy expenditure may be sufficient to prevent these effects. To test this hypothesis, male Sprague-Dawley rats received an oral lipid gavage (20% intralipid, 45 Kcal/kg lean body mass) or water followed either by 2h of rest or 1h of rest plus 1h of low intensity treadmill exercise (15 m/min, 0% grade). Permeabilized fiber bundles were prepared from red gastrocnemius muscle for testing mitochondrial function. In rats receiving lipid, {Delta}{Psi}m and mEH2O2 were higher (P<0.05) and calcium retention capacity (mCa2+RC, an index of resistance to mitochondrial permeability transition) was lower under state IV and/or "clamped" ADP-stimulated state III conditions. All three effects were prevented when lipid gavage was followed by low-intensity exercise. Respiratory capacity was unaffected by any of the interventions. These findings provide evidence that mitochondrial {Delta}{Psi}m, mEH2O2, and mCa2+RC are acutely affected by nutritional overload in skeletal muscle, but can be prevented by low intensity exercise. NIH DK073488ented by low intensity exercise. NIH DK073488)
Ortega 2017 Biol Reprod + (A single missense mutation at position 159 … A single missense mutation at position 159 of coenzyme Q9 (COQ9) (G→A; rs109301586) has been associated with genetic variation in fertility in Holstein cattle, with the A allele associated with higher fertility. COQ9 is involved in the synthesis of coenzyme COQ10, a component of the electron transport system of the mitochondria. Here we tested whether reproductive phenotype is associated with the mutation and evaluated functional consequences for cellular oxygen metabolism, body weight changes, and ovarian function. The mutation in COQ9 modifies predicted tertiary protein structure and affected mitochondrial respiration of peripheral blood mononuclear cells. The A allele was associated with low resting oxygen consumption and high electron transport system capacity. Phenotypic measurements for fertility were evaluated for up to five lactations in a population of 2273 Holstein cows. There were additive effects of the mutation (P < 0.05) in favor of the A allele for pregnancy rate, interval from calving to conception, and services per conception. There was no association of genotype with milk production or body weight changes ''postpartum''. The mutation in COQ9 affected ovarian function; the A allele was associated with increased mitochondrial DNA copy number in oocytes, and there were overdominance effects for COQ9 expression in oocytes, follicle number, and antimullerian hormone concentrations. Overall, results show how a gene involved in mitochondrial function is associated with overall fertility, possibly in part by affecting oocyte quality.possibly in part by affecting oocyte quality.)
Du 1998 Free Radic Biol Med + (A small portion of the oxygen consumed by … A small portion of the oxygen consumed by aerobic cells is converted to superoxide anion at the level of the mitochondrial respiratory chain. If produced in excess, this harmful radical is considered to impair cellular structures and functions. Damage at the level of mitochondria have been reported after ischemia and reperfusion of organs. However, the complexity of the ''in vivo'' system prevents from understanding and describing precise mechanisms and locations of mitochondrial impairment. An ''in vitro'' model of isolated-mitochondria anoxia-reoxygenation is used to investigate superoxide anion generation together with specific damage at the level of mitochondrial oxidative phosphorylation. Superoxide anion is detected by electron paramagnetic resonance spin trapping with POBN-ethanol. Mitochondrial respiratory parameters are calculated from oxygen consumption traces recorded with a Clark electrode. Respiring mitochondria produce superoxide anion in unstressed conditions, however, the production is raised during postanoxic reoxygenation. Several respiratory parameters are impaired after reoxygenation, as shown by decreases of phosphorylating and uncoupled respiration rates and of ADP/O ratio and by increase of resting respiration. Partial protection of mitochondrial function by POBN suggests that functional damage is related and secondary to superoxide anion production by the mitochondria ''in vitro''.oduction by the mitochondria ''in vitro''.)
Hellgren 2016 Abstract Proceedings of The Physiological Society + (A suboptimal prenatal environment can affe … A suboptimal prenatal environment can affect organogenesis and the natural development of an individual by epigenetic modifications of the genome. While these changes are permanent, it is common not to see any pathological effects until adulthood. The impact of nutritional insults during development has been well-studied in a wide variation of physiological systems. Less studied however, are the effects of hypoxic developmental insults. To this end, our aim is to investigate the long-term effects of prenatal hypoxia on cardiovascular metabolism of adult offspring. We have utilised spectrophotometry to investigate mitochondrial enzyme activity combined with high resolution respirometry to investigate ''in vivo'' mitochondrial efficiency and production of reactive oxygen species. With these methods we aim to identify changes in myocardial mitochondrial energy production, taking a step towards understanding the effect of intrauterine hypoxia on cardiac energetics. Pregnant mice were placed in hypoxic chambers with 14% O2 from gestational day 3-19 and reared in normoxia until six months of age. Heart tissue was harvested and enzymatic activity of citrate synthase and mitochondrial Electron Transport Chain Complexes I-IV was measured using spectrophotometry. High-resolution respirometry lets us further investigate the status of the mitochondria, with emphasis on oxygen consumption and ROS production. Preliminary data show promising differences between treatment and control groups, as well as sexual dimorphism regarding response and effect. We hope to be able to identify possible mechanistic changes, on a cellular level, that underlie the pathological cardiovascular phenotype associated with intrauterine hypoxia.scular phenotype associated with intrauterine hypoxia.)
Petrus 2015 Can J Physiol Pharmacol + (A substantial body of evidence indicates t … A substantial body of evidence indicates that pharmacological activation of mitochondrial ATP-sensitive potassium channels (mKATP) in the heart is protective in conditions associated with ischemia/reperfusion injury. Several mechanisms have been postulated to be responsible for cardioprotection, including the modulation of mitochondrial respiratory function. The aim of the present study was to characterize the dose-dependent effects of novel synthetic benzopyran analogues, derived from a BMS-191095, a selective mKATP opener, on mitochondrial respiration and reactive oxygen species (ROS) production in isolated rat heart mitochondria. Mitochondrial respiratory function was assessed by high-resolution respirometry, and H2O2 production was measured by the Amplex Red fluorescence assay. Four compounds, namely KL-1487, KL-1492, KL-1495, and KL-1507, applied in increasing concentrations (50, 75, 100, and 150 μmol/L, respectively) were investigated. When added in the last two concentrations, all compounds significantly increased State 2 and 4 respiratory rates, an effect that was not abolished by 5-hydroxydecanoate (5-HD, 100 μmol/L), the classic mKATP inhibitor. The highest concentration also elicited an important decrease of the oxidative phosphorylation in a K(+) independent manner. Both concentrations of 100 and 150 μmol/L for KL-1487, KL-1492, and KL-1495, and the concentration of 150 μmol/L for KL-1507, respectively, mitigated the mitochondrial H2O2 release. In isolated rat heart mitochondria, the novel benzopyran analogues act as protonophoric uncouplers of oxidative phosphorylation and decrease the generation of reactive oxygen species in a dose-dependent manner.ylation and decrease the generation of reactive oxygen species in a dose-dependent manner.)
Gnaiger 2011 Abstract-Berlin + (A tight relationship is described between … A tight relationship is described between mitochondrial respiratory capacity of human skeletal muscle and physical fitness, which quantifies the decline of respiratory function as the result of a sedentary life style in the progression towards obesity [1]. Tissue-OXPHOS capacity is the capacity of oxidative phosphorylation in skeletal muscle, which is the product of mitochondrial density and respiratory intensity (structure times function; i.e. mitochondrial marker per tissue mass times OXPHOS capacity per mitochondrial marker). Tissue-OXPHOS capacity per unit wet weight [pmol O2∙s-1∙mg-1] is measured directly in permeabilized muscle fibres, and high-resolution respirometry provides a routine approach under physiological conditions (37 °C; Complex I+II substrate combination) with minimal amounts of tissue biopsy (1 to 3 mg wet weight per assay) [2].In healthy subjects varying from athletic to sedentary life styles, tissue-OXPHOS capacity of vastus lateralis increases linearly with maximum aerobic ergometric performance (''V''O2max) and declines steeply with body mass index (BMI=body mass per body height squared [kg/m2]) in the range of 180 to 60 pmol O2∙s-1∙mg-1. The tissue-OXPHOS/BMI relationship spans from endurance athletes and physically active subjects (normal BMI 20-25), overweight individuals (BMI 25-30) with predominantly sedentary life style, to obese patients who are qualified as healthy controls in studies of type 2 diabetes (BMI >30). Total muscle tissue is unchanged or increases rather than decreases with higher BMI, whereas over-proportionally reduced mitochondrial density per muscle mass explains the loss of aerobic ergometric performance in the sedentary life style and development of obesity. Mitochondrial quality (OXPHOS capacity per mitochondrial marker) is largely maintained, but fatty acid oxidation capacity and coupling control decline as a result of diminishing exercise [2]. Specific mitochondrial injuries accumulate as a consequence of reduced mitochondrial density and correspondingly low mitochondrial turnover. Based on the tissue-OXPHOS/BMI relationship and integrating known mechanisms responsible for dysregulation of mitochondrial biosynthesis under conditions of chronic low-grade inflammation, low mitochondrial density is a primary risk factor related to a wide range of degenerative diseases, including type 2 diabetes. The health benefits are emphasized of maintaining muscle mitochondrial density high, particularly with progressive age, as achieved by a physically active and nutritionally normal life style. The diagnostic perspective gained from analysis of mitochondrial competence after exercise training2 challenges the definition of the control group [3]: Are sedentary subjects healthy? Contribution to K-Regio ''[[MitoCom_O2k-Fluorometer|MitoCom Tyrol]]''.1. [[Gnaiger 2009 Int J Biochem Cell Biol|Gnaiger E (2009) Capacity of oxidative phosphorylation in human skeletal muscle. New perspectives of mitochondrial physiology. Int. J. Biochem. Cell Biol. 41: 1837–1845.]]2. [[Pesta_2011_AJP|Pesta D, Hoppel F, Macek C, Messner H, Faulhaber M, Kobel C, Parson W, Burtscher M, Schocke M, Gnaiger E (2011) Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans. Am. J. Physiol. Regul. Integr. Comp. Physiol. doi: 10.1152/ajpregu.00285.2011]]3. Martin B, Ji S, Maudsley S, Mattson MP (2010) "Control" laboratory rodents are metabolically morbid: why it matters. Proc. Natl. Acad. Sci. USA 107: 6127-6133.ttson MP (2010) "Control" laboratory rodents are metabolically morbid: why it matters. Proc. Natl. Acad. Sci. USA 107: 6127-6133.)
Gnaiger 2016 Abstract Mito Xmas Meeting Innsbruck + (A variety of lifestyles developed in human … A variety of lifestyles developed in human populations to cope with the environmental and socioeconomic conditions in the inhabited areas of our world. Extremes at high altitude and latitude impose stress conditions which require adjustments in physiological performance or limit permanent settlements. Modern strength and endurance training regimes may be closely linked to a variety of traditional life styles. Diversity is nature’s treasure and the subject of comparative physiology [1].The Polar Inuit of Thule and Qaarnaak in Greenland are among the northernmost populations. This human heritage of a culture and physiological type is endangered not only by a historical politically forced limitation of their territory, but by the current effects of global environmental pollution and climate change, causing social destabilization and a shift towards an unhealthy sedentary in contrast to the traditional active life style of Inuit hunters. The uncoupling hypothesis for mitochondrial haplogroups of arctic populations suggests that lower coupling of mitochondrial respiration to ATP production was selected for in favour of higher heat dissipation as an adaptation to cold climates through a higher mitochondrial proton leak [2]. Our studies show that mitochondrial coupling control in skeletal muscle of Inuit haplogroups is identical to Danes from western Europe haplogroups, such that biochemical coupling efficiency was preserved across variations in muscle fibre type and lifestyle [3]. Unexpectedly, total capacity of oxidative phosphorylation (OXPHOS) in the leg of the Inuit hunters was lower compared to untrained Danes. In line with this apparent ‘mitochondrial paradox’, total OXPHOS capacity decreased in the Danes during 42 days of active skiing on the sea ice in northern Greenland. The Inuit had a higher capacity to oxidize fat substrate in skeletal muscle which increased in Danes approaching the level of the Inuit. A common pattern emerges of mitochondrial acclimatization and evolutionary adaptation in humans at high latitude and high altitude [3-4]: In these environments, economy of locomotion is optimized by preservation of biochemical coupling efficiency at modest mitochondrial density, when ''V''O2max and sustained submaximum performance are not dependent on peripherally increased capacities of oxidative phosphorylation.lly increased capacities of oxidative phosphorylation.)
Maddalena 2017 Biochim Biophys Acta + (A variety of mitochondria-targeted small m … A variety of mitochondria-targeted small molecules have been invented to manipulate mitochondrial redox activities and improve function in certain disease states. 3-Hydroxypropyl-triphenylphosphonium-conjugated imidazole-substituted oleic acid (TPP-IOA) was developed as a specific inhibitor of cytochrome c peroxidase activity that inhibits apoptosis by preventing cardiolipin oxidation and cytochrome c release to the cytosol. Here we evaluate the effects of TPP-IOA on oxidative phosphorylation in isolated mitochondria and on mitochondrial function in live cells. We demonstrate that, at concentrations similar to those required to achieve inhibition of cytochrome c peroxidase activity, TPP-IOA perturbs oxidative phosphorylation in isolated mitochondria. In live SH-SY5Y cells, TPP-IOA partially collapsed mitochondrial membrane potential, caused extensive fragmentation of the mitochondrial network, and decreased apparent mitochondrial abundance within 3h of exposure. Many cultured cell lines rely primarily on aerobic glycolysis, potentially making them less sensitive to small molecules disrupting oxidative phosphorylation. We therefore determined the anti-apoptotic efficacy of TPP-IOA in SH-SY5Y cells growing in glucose or in galactose, the latter of which increases reliance on oxidative phosphorylation for ATP supply. The anti-apoptotic activity of TPP-IOA that was observed in glucose media was not seen in galactose media. It therefore appears that, at concentrations required to inhibit cytochrome c peroxidase activity, TPP-IOA perturbs oxidative phosphorylation. In light of these data it is predicted that potential future therapeutic applications of TPP-IOA will be restricted to highly glycolytic cell types with limited reliance on oxidative phosphorylation.Copyright © 2016 Elsevier B.V. All rights reserved. © 2016 Elsevier B.V. All rights reserved.)
Mould 2023 Front Physiol + (A wide variety of studies have reported so … A wide variety of studies have reported some form of non-chemical or non-aqueous communication between physically isolated organisms, eliciting changes in cellular proliferation, morphology, and/or metabolism. The sources and mechanisms of such signalling pathways are still unknown, but have been postulated to involve vibration, volatile transmission, or light through the phenomenon of ultraweak photon emission. Here, we report non-chemical communication between isolated mitochondria from MCF7 (cancer) and MCF10A (non-cancer) cell lines. We found that mitochondria in one cuvette stressed by an electron transport chain inhibitor, antimycin, alters the respiration of mitochondria in an adjacent, but chemically and physically separate cuvette, significantly decreasing the rate of oxygen consumption compared to a control (p = <0.0001 in MCF7 and MCF10A mitochondria). Moreover, the changes in O2-consumption were dependent on the origin of mitochondria (cancer vs. non-cancer) as well as the presence of "ambient" light. Our results support the existence of non-chemical signalling between isolated mitochondria. The experimental design suggests that the non-chemical communication is light-based, although further work is needed to fully elucidate its nature.work is needed to fully elucidate its nature.)
Li 2020 G3 (Bethesda) + (A yeast deletion mutation in the nuclear-e … A yeast deletion mutation in the nuclear-encoded gene, AFO1, which codes for a mitochondrial ribosomal protein, led to slow growth on glucose, the inability to grow on glycerol or ethanol, and loss of mitochondrial DNA and respiration. We noticed that afo1- yeast readily obtains secondary mutations that suppress aspects of this phenotype, including its growth defect. We characterized and identified a dominant missense suppressor mutation in the ATP3 gene. Comparing isogenic slowly growing rho-zero and rapidly growing suppressed afo1- strains under carefully controlled fermentation conditions showed that energy charge was not significantly different between strains and was not causal for the observed growth properties. Surprisingly, in a wild-type background, the dominant suppressor allele of ATP3 still allowed respiratory growth but increased the petite frequency. Similarly, a slow-growing respiratory deficient afo1- strain displayed an about twofold increase in spontaneous frequency of point mutations (comparable to the rho-zero strain) while the suppressed strain showed mutation frequency comparable to the repiratory-competent WT strain. We conclude, that phenotypes that result from afo1- are mostly explained by rapidly emerging mutations that compensate for the slow growth that typically follows respiratory deficiency.tations that compensate for the slow growth that typically follows respiratory deficiency.)
Papadimitriou 2018 Thesis + (ACTN3 has been labelled as the ‘gene for s … ACTN3 has been labelled as the ‘gene for speed’ due to the increased frequency of the R allele encoding the α-actinin-3 protein in elite sprint athletes compared to the general population. The results of the first study of this thesis demonstrate that elite athletes who express α-actinin-3 (ACTN3 RR genotype) have faster sprint times compared to those who do not express α-actinin-3 (ACTN3 XX genotype). Further analysis indicates that the ACTN3 genotype accounts for 0.92% in sprint speed amongst elite 200-m athletes. In study two, the same quantitative genetic epidemiological design applied to elite endurance athletes, showed no evidence that a trade-off existed. The endurance athletes with the ACTN3 XX genotype were no faster than those who express the α-actinin-3 protein. These results added to literature that it is unlikely the ACTN3 XX genotype to offer an advantage for endurance performance. While ACTN3 genotype does not appear to influence endurance performance in athletes, studies in mice that completely lack the α-actinin-3 protein suggest the ACTN3 genotype influences the adaptive response to endurance exercise. Based on these findings, the aim of study 3 was to investigate if ACTN3 genotype influences exercise-induced changes in the content of genes and proteins associated with mitochondrial biogenesis. At baseline, there was a compensatory greater α-actinin-2 protein content in ACTN3 XX vs ACTN3 RR participants (p=0.018) but there were no differences in the endurance-related phenotypes measured. There was a main effect of genotype (p=0.006), without a significant interaction effect, for RCAN1-4 or significant exercise-induced expression of genes associated with mitochondrial biogenesis. Together, these results suggest that ACTN3 genotype has a small but significant influence on sprint speed amongst elite sprint athletes. However, loss of α-actinin-3 protein is not associated with higher values for endurance-related phenotypes, endurance performance, or a greater adaptive response to a single session of high-intensity endurance exercise.sion of high-intensity endurance exercise.)
Kotiadis 2012 J Cell Sci + (ADF/cofilin family proteins are essential … ADF/cofilin family proteins are essential regulators of actin cytoskeletal dynamics. Recent evidence also implicates cofilin in the regulation of mitochondrial function. Here, we identify new functional surfaces of cofilin that are linked with mitochondrial function and stress responses in the budding yeast ''S. cerevisiae''. Our data links surfaces of cofilin that are involved in separable activities of actin filament disassembly or stabilisation, to the regulation of mitochondrial morphology and the activation status of Ras respectively. Importantly, charge alterations to conserved surfaces of cofilin that do not interfere with its actin regulatory activity leads to a dramatic increase in respiratory function that triggers a retrograde signal to up-regulate a battery of ABC transporters and concurrent metabolic changes that support multi-drug resistance. We hypothesise that cofilin functions within a novel bio-sensing system that connects the cytoskeleton and mitochondrial function to environmental challenge.drial function to environmental challenge.)
Scheibye-Knudsen 2009 Eur J Appl Physiol + (ADP is generally accepted as a key regulat … ADP is generally accepted as a key regulator of oxygen consumption both in isolated mitochondria and in permeabilized fibers from skeletal muscle. The present study explored inorganic phosphate in a similar regulatory role. Saponin permeabilized fibers and isolated mitochondria from type-I and type-II muscle from male Wistar rats were prepared. Respiration was measured while the medium Pi concentration was gradually increased. The apparent Km values for Pi were 607 ± 17 µM and 405 ± 15 μM (P < 0.0001) for type-I and type-II fibers, respectively. For isolated mitochondria the values were significantly lower than type-1 permeabilized fibers, 338 ± 130 μM and 235 ± 30 μM (P < 0.05), but not different with respect to fiber type. The reason for this difference in Km values in the permeabilized muscle is unknown, but a similar pattern has been observed for K m of ADP. Our data indicate that phosphate may play a role in regulation of oxygen consumption ''in vitro'' and ''in vivo''.oxygen consumption ''in vitro'' and ''in vivo''.)