Newell 2016 Physiol Entomol

Newell C, Kane CL, Kane DC (2016) Mitochondrial substrate specificity in beetle flight muscle: assessing respiratory oxygen flux in small samples from Dermestes maculatus and Tenebrio molitor. Physiol Entomol p7.

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Newell C, Kane CL, Kane DC (2016) Physiol Entomol

Abstract: In the present study, the permeabilized fibre approach is adapted to investigate substrate utilization patterns in the flight muscle mitochondria of Dermestes maculatus (Coleoptera: Dermestidae; a carrion scavenger beetle) and Tenebrio molitor (Coleoptera: Tenebrionidae; a phytophagous scavenger beetle). Respiration in saponin-permeabilized fibres is measured during titration of palmitoyl-carnitine (Palm-C), pyruvate (Pyr) or l-glycerol 3-phosphate (G3-P). Michaelis–Menten-type enzyme kinetics for oxygen consumption are observed as a function of substrate concentration in Pyr and G3-P, from which substrate-specific apparent Km (sensitivity) and Vmax (capacity) are determined. Compared with D. maculatus, the apparent Km in T. molitor is lower (P<0.001) for Pyr, and Vmax is greater for G3-P (P<0.001). In D. maculatus, the apparent Km for G3-P is greater (P<0.001), and respiratory Vmax is lower (P<0.001), than kinetics for Pyr. Robust respiration with l-proline (Pro) is also observed in both beetle species tested; however, it is over 2.5-fold greater in D. maculatus than T. molitor (P<0.05). These results demonstrate that respiration in beetle flight muscle mitochondria can be assessed in small samples (i.e. at the individual beetle level) using the approach adapted for the present study. The results of the present study also highlight the substrate oxidative capacity patterns. • Keywords: Insect, Metabolism, Permeabilized fibres, Skeletal muscle, Buffer z, Proline, Blebbistatin

• O2k-Network Lab: CA Antigonish Kane DA, CA Calgary Shearer J, CA Montreal Hepple RT, US NC Greenville Neufer PD

Labels: MiParea: Respiration, Comparative MiP;environmental MiP 

Organism: Hexapods  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

Regulation: Substrate  Coupling state: OXPHOS  Pathway: F, N, Gp, Other combinations  HRR: Oxygraph-2k 

2016-03