Scott Katrina Y, Matthew Rebecca, Woolcock Jennifer, Silva Maise, Lemieux Hélène
Faculty Saint-Jean, University of Alberta, Edmonton, AB, Canada, T6C 4G9.
Faculdade de Tecnologia e Ciências, Salvador, Bahia, 41741-590, Brazil.
J Exp Biol. 2019 Sep 12;222(Pt 18):jeb207951. doi: 10.1242/jeb.207951.
As the world's climate changes, life faces an evolving thermal environment. Mitochondrial oxidative phosphorylation (OXPHOS) is critical to ensure sufficient cellular energy production, and it is strongly influenced by temperature. The thermally induced changes to the regulation of specific steps within the OXPHOS process are poorly understood. In our study, we used the eurythermal species of planarian to study the thermal sensitivity of the OXPHOS process at 10, 15, 20, 25 and 30°C. We conducted cold acclimation experiments where we measured the adjustment of specific steps in OXPHOS at two assay temperatures (10 and 20°C) following 4 weeks of acclimation under normal (22°C) or low (5°C) temperature conditions. At the low temperature, the contribution of the NADH pathway to the maximal OXPHOS capacity, in a combined pathway (NADH and succinate), was reduced. There was partial compensation by an increased contribution of the succinate pathway. As the temperature decreased, OXPHOS became more limited by the capacity of the phosphorylation system. Acclimation to the low temperature resulted in positive adjustments of the NADH pathway capacity due, at least in part, to an increase in complex I activity. The acclimation also resulted in a better match between OXPHOS and phosphorylation system capacities. Both of these adjustments following acclimation were specific to the low assay temperature. We conclude that there is substantial plasticity in the mitochondrial OXPHOS process following thermal acclimation in , and this probably contributes to the wide thermal range of the species.
随着全球气候变化，生物面临着不断演变的热环境。线粒体氧化磷酸化（OXPHOS）对于确保细胞产生足够的能量至关重要，并且它受到温度的强烈影响。人们对氧化磷酸化过程中特定步骤的调节因热而发生的变化了解甚少。在我们的研究中，我们使用广温性涡虫物种来研究在10、15、20、25和30°C下氧化磷酸化过程的热敏感性。我们进行了冷驯化实验，在正常（22°C）或低温（5°C）条件下驯化4周后，在两个测定温度（10和20°C）下测量氧化磷酸化中特定步骤的调整情况。在低温下，在联合途径（NADH和琥珀酸）中，NADH途径对最大氧化磷酸化能力的贡献降低。琥珀酸途径贡献的增加起到了部分补偿作用。随着温度降低，氧化磷酸化受到磷酸化系统能力的限制更大。适应低温导致NADH途径能力的正向调整，这至少部分是由于复合体I活性的增加。这种适应还导致氧化磷酸化与磷酸化系统能力之间的匹配更好。适应后的这两种调整都特定于低测定温度。我们得出结论，涡虫热适应后线粒体氧化磷酸化过程具有很大的可塑性，这可能有助于该物种具有较宽的热耐受范围。
