Chicco 2014 J Exp Biol

From Bioblast
Publications in the MiPMap
Chicco AJ, Le CH, Schlater AE, Nguyen AD, Kaye SD, Beals JW, Scalzo RL, Bell C, Gnaiger E, Costa DP, Crocker DE, Kanatous SB (2014) High fatty acid oxidation capacity and phosphorylation control despite elevated leak and reduced respiratory capacity in northern elephant seal muscle mitochondria. J Exp Biol 217:2947-55.

Β» PMID: 24902742 Open Access

Chicco AJ, Le CH, Schlater AE, Nguyen AD, Kaye SD, Beals JW, Scalzo RL, Bell C, Gnaiger Erich, Costa DP, Crocker DE, Kanatous SB (2014) J Exp Biol

Abstract: Northern elephant seals (Mirounga angustirostris) are extreme, hypoxia-adapted endotherms that rely largely on aerobic metabolism during extended breath-hold dives in near freezing water temperatures. While many aspects of their physiology have been characterized to account for these remarkable feats, the contribution of adaptations in the aerobic powerhouses of muscle cells, the mitochondria, are unknown. In the present study, the ontogeny and comparative physiology of elephant seal muscle mitochondrial respiratory function was investigated under a variety of substrate conditions and respiratory states. Intact mitochondrial networks were studied by high-resolution respirometry in saponin-permeabilized fiber bundles obtained from primary swimming muscles of pup, juvenile, and adult seals, and compared to fibers from adult human vastus laterais. Results indicate that seal muscle maintains a high capacity for fatty acid oxidation despite a progressive decrease in total respiratory capacity as animals mature from pups to adults. This is explained by a progressive increase in phosphorylation control and fatty acid utilization over pyruvate in adult seals compared to humans and seal pups. Interestingly, despite higher indices of oxidative phosphorylation efficiency, juvenile and adult seals also exhibit a ~50% greater capacity for respiratory leak compared to humans and pups. The ontogeny of this phenotype suggests it is an adaptation of muscle to the prolonged breath-hold exercise and highly variable ambient temperatures experienced by mature elephant seals. These studies highlight the remarkable plasticity of mammalian mitochondria to meet the demands for both efficient ATP production and endothermy in a cold, oxygen-limited environment.

β€’ Keywords: Adaptive thermogenesis; Diving mammals; Hypoxia adaptations; Mitochondria

β€’ O2k-Network Lab: US CO Fort Collins Chicco AJ, AT Innsbruck OROBOROS, AT Innsbruck Gnaiger E

Cited by

Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Developmental biology 

Stress:Ischemia-reperfusion, Temperature  Organism: Human, Other mammals  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 

Regulation: Temperature  Coupling state: LEAK, OXPHOS, ET  Pathway: F, N, S, NS  HRR: Oxygraph-2k 

Cookies help us deliver our services. By using our services, you agree to our use of cookies.