Widener University, Department of Biology, One University Place, Chester, PA 19013, USA.
Widener University, Department of Biology, One University Place, Chester, PA 19013, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2023 Feb;276:111354. doi: 10.1016/j.cbpa.2022.111354. Epub 2022 Dec 1.
As climate change alters the thermal environment of the planet, interest has grown in how animals may mitigate the impact of a changing environment on physiological function. Thermal acclimation to a warm environment may, for instance, blunt the impact of a warming environment on metabolism by allowing a fish to shift to slower isoforms of functionally significant proteins such as myosin heavy chain. The thermal acclimation of brook trout (Salvelinus fontinalis) was examined by comparing swimming performance, myotomal muscle contraction kinetics and muscle histology in groups of fish acclimated to 4, 10 and 20 °C. Brook trout show a significant acclimation response in their maximum aerobic swimming performance (U), with acclimation to warm water leading to lower U values. Maximum muscle shortening velocity (V) decreased significantly with warm acclimation for both red or slow-twitch and white or fast-twitch muscle. Immunohistochemical analysis of myotomal muscle suggests changes in myosin expression underly the thermal acclimation of swimming performance and contraction kinetics. Physiological and histological data suggest a robust acclimation response to a warming environment, one that would reduce the added metabolic costs incurred by an ectotherm when environmental temperature rises for sustained periods of time.
随着气候变化改变地球的热环境，人们对动物如何减轻环境变化对生理功能的影响越来越感兴趣。例如，动物在温暖环境中的热驯化可能会使鱼类转向肌球蛋白重链等功能重要蛋白的较慢同工型，从而减轻环境变暖对新陈代谢的影响。通过比较适应 4、10 和 20°C 的鱼类的游泳性能、肌节肌肉收缩动力学和肌肉组织学，研究了溪红点鲑（Salvelinus fontinalis）的热驯化。溪红点鲑在最大有氧游泳性能（U）上表现出明显的驯化反应，温水驯化导致 U 值降低。红肌或慢肌和白肌或快肌的最大肌肉缩短速度（V）随温水驯化显著降低。肌节肌肉的免疫组织化学分析表明，肌球蛋白表达的变化是游泳性能和收缩动力学热驯化的基础。生理和组织学数据表明，对温暖环境有很强的适应能力，这将降低变温动物在环境温度持续升高时所产生的额外代谢成本。
