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Martinez 2013 Marine Biol

From Bioblast
Publications in the MiPMap
Martinez E, Menze MA, Torres JJ (2013) Mitochondrial energetics of benthic and pelagic Antarctic teleosts. Marine Biol 160:2813-23.

ยป 2273

Martinez E, Menze MA, Torres JJ (2013) Marine Biol

Abstract: Antarctic fauna are highly adapted to the frigid waters of the Southern Ocean. This study describes the in vitro temperature sensitivity of oxygen consumption rates measured in liver mitochondria from the pelagic notothenioid Pleuragramma antarcticum between 5 and 35 ยฐC. Oxygen fluxes were measured after the addition of millimolar levels of pyruvate, malate, succinate and glutamate (LEAK) and saturating levels of ADP [oxidative phosphorylation (OXPHOS)]. OXPHOS respiration significantly decreased above 18.7 ยฐC. A comparison of the oxidative capacities among P. antarcticum and other notothenioids showed significant differences in OXPHOS respiration, where benthic species exhibited about 50% lower OXPHOS capacities than P. antarcticum. In addition, OXPHOS capacities normalized per milligram of mitochondrial protein of P. antarcticum were up to eight times higher than those reported in the literature for other notothenioids. The comparatively high respiration rates measured in this study may be explained by our approach, which engaged both Complexes I and II under conditions of oxidative phosphorylation. OXPHOS capacities of independently activated Complexes I and II were found to range from 42 to 100% of rates obtained when both complexes were activated simultaneously in the same species. The remarkable tolerance of P. antarcticum OXPHOS toward warmer temperatures was unexpected for an Antarctic stenotherm and may indicate that thermal sensitivity of their mitochondria is not the driving force behind their stenothermy.


โ€ข O2k-Network Lab: US IL Charleston Menze MA, US LA Baton Rouge Hand SC, US KY Louisville Menze MA


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 


Organism: Fishes  Tissue;cell: Liver  Preparation: Homogenate 

Regulation: Temperature  Coupling state: LEAK, OXPHOS, ET  Pathway: N, S, NS