Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France.
Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary.
Biol Lett. 2021 Feb;17(2):20200759. doi: 10.1098/rsbl.2020.0759. Epub 2021 Feb 10.
Aerobic metabolism of aquatic ectotherms is highly sensitive to fluctuating climates. Many mitochondrial traits exhibit phenotypic plasticity in response to acute variations in temperature and oxygen availability. These responses are critical for understanding the effects of environmental variations on aquatic ectotherms' performance. Using the European seabass, , we determined the effects of acute warming and deoxygenation on mitochondrial respiratory capacities and mitochondrial efficiency to produce ATP (ATP/O ratio). We show that acute warming reduced ATP/O ratio but deoxygenation marginally raised ATP/O ratio, leading to a compensatory effect of low oxygen availability on mitochondrial ATP/O ratio at high temperature. The acute effect of warming and deoxygenation on mitochondrial efficiency might be related to the leak of protons across the mitochondrial inner membrane, as the mitochondrial respiration required to counteract the proton leak increased with warming and decreased with deoxygenation. Our study underlines the importance of integrating the combined effects of temperature and oxygen availability on mitochondrial metabolism. Predictions on decline in performance of aquatic ectotherms owing to climate change may not be accurate, since these predictions typically look at respiratory capacity and ignore efficiency of ATP production.
水生变温动物的有氧代谢对波动的气候高度敏感。许多线粒体特征表现出对温度和氧气供应急性变化的表型可塑性。这些反应对于理解环境变化对水生变温动物表现的影响至关重要。我们使用欧洲海鲈（ ），确定了急性升温和解氧对线粒体呼吸能力和产生 ATP 的线粒体效率（ATP/O 比）的影响。我们表明，急性升温降低了 ATP/O 比，但解氧略微提高了 ATP/O 比，导致低氧可用性在高温下对线粒体 ATP/O 比产生补偿效应。升温和解氧对线粒体效率的急性影响可能与质子穿过线粒体内膜的泄漏有关，因为为了抵消质子泄漏而增加的线粒体呼吸随着升温而增加，随着解氧而减少。我们的研究强调了整合温度和氧气可用性对线粒体代谢的综合影响的重要性。由于气候变化而导致水生变温动物表现下降的预测可能不准确，因为这些预测通常只考虑呼吸能力而忽略了 ATP 产生的效率。
