Physiol Biochem Zool. 2022 Jan-Feb;95(1):15-21. doi: 10.1086/716904.
AbstractIn ectotherms, it is well described that thermal acclimation induces compensatory adjustments maintaining mitochondrial functions across large shifts in temperature. However, until now, studies mostly focused on fluxes of oxygen without knowing whether mitochondrial efficiency to produce ATP (ATP/O ratio) is also dependent on temperature acclimation. We thus measured thermal reaction norms of oxidative phosphorylation activity and efficiency in isolated mitochondria from skeletal muscle of sea bass () juveniles acclimated at optimal (22°C), low (18°C), and high (26°C) temperatures. The mitochondrial fluxes (oxygen consumption and ATP synthesis) increased with increasing assay temperatures and were on the whole higher in fishes acclimated at 18°C than in the other two groups. However, these mitochondrial rates were not significantly different between experimental groups when they were compared at the acclimation temperature. In contrast, we show that acclimation to high, and not low, temperature improved mitochondrial efficiency (on average >15%). This higher efficiency in high-temperature-acclimated fishes is also apparent when compared at respective acclimation temperatures. This mitochondrial phenotype would favor an economical management of oxygen in response to harsh energetic constraints associated with warming water.
摘要 在变温动物中，热驯化会诱导补偿性调整，从而在较大的温度变化范围内维持线粒体功能，这一现象已经得到了很好的描述。然而，到目前为止，大多数研究主要集中在氧气通量上，而不知道线粒体产生 ATP 的效率（ATP/O 比）是否也依赖于温度驯化。因此，我们测量了适应于最佳温度（22°C）、低温（18°C）和高温（26°C）的海鲈（）幼鱼骨骼肌分离线粒体的氧化磷酸化活性和效率的热反应规范。线粒体通量（耗氧量和 ATP 合成量）随着测定温度的升高而增加，在适应于 18°C 的鱼类中，整体上高于其他两组。然而，当在适应温度下比较时，这些线粒体速率在实验组之间没有显著差异。相比之下，我们表明，高温驯化，而不是低温驯化，提高了线粒体效率（平均提高了 15%以上）。在比较各自的适应温度时，高温驯化鱼类的这种更高的线粒体效率也很明显。这种线粒体表型有利于在与水温升高相关的苛刻能量限制下，对氧气进行经济管理。
