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Thermal sensitivity of mitochondrial function in the Antarctic Notothenioid Lepidonotothen nudifrons

Hardewig, I.; Peck, L. S.; Pörtner, H. O.. 1999 Thermal sensitivity of mitochondrial function in the Antarctic Notothenioid Lepidonotothen nudifrons. Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, 169 (8). 597-604. 10.1007/s003600050260

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Abstract/Summary

The thermal sensitivity of mitochondrial function was investigated in the stenothermal Antarctic fish Lepidonotothen nudifrons. State 3 respiration increases with increasing temperature between 0 °C and 18 °C with a Q 10 of 2.43–2.63. State 4 respiration in the presence of oligomycin, an inhibitor of mitochondrial ATP synthase, quantifies the leakage of protons through the inner mitochondrial membrane, which causes oxygen consumption without concomitant ATP production. This parameter shows an unusually high Q 10 of 4.21 ± 0.42 (0–18 °C), which indicates that proton leakage does not depend merely on ion diffusion but is an enzyme-catalysed process. The differential thermal sensitivity of oxidative phosphorylation (=state 3) and proton leakage (=state 4 in the presence of oligomycin) leads to progressive uncoupling of the mitochondria and decreased efficiency of oxidative phosphorylation under in vivo conditions if the body temperature of L. nudifrons increases.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1007/s003600050260
Programmes: BAS Programmes > Pre 2000 programme
ISSN: 0174-1578
Additional Keywords: Antarctic fish, temperature, mitochondrial respiration, proton leakage, isocitrate dehydrogenase
Date made live: 15 Oct 2013 09:09 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/503502

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