Mechanisms and costs of mitochondrial thermal acclimation in a eurythermal killifish (Fundulus heteroclitus)
Mechanisms and costs of mitochondrial thermal acclimation in a eurythermal killifish (Fundulus heteroclitus)
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DOI：
10.1242/jeb.120444
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发表时间：
2015-06-01
影响因子：
2.8
通讯作者：
Schulte, Patricia M.
中科院分区：
文献类型：
--
作者：
Chung, Dillon J.;Schulte, Patricia M.
作用于线粒体水平的过程被认为会影响生物体的热极限。为了确定线粒体特性的变化是否可能导致热极限的变化，我们研究了线粒体特性是如何受到广温性鳉鱼，Fundulus heteroclitus -一种在整个生物体热极限中具有大量可塑性的物种的热适应的影响。我们假设热适应会导致线粒体功能的变化，这可能导致急性热变化期间功能的权衡。我们测量了线粒体呼吸速率（（V）点（O2）），通过电子传递系统的多个复杂的热适应（至5，15，33摄氏度），并评估了线粒体膜电位（Δ p）和活性氧（ROS）的生产率作为估计成本的维护。驯化至5摄氏度导致在低温下线粒体呼吸的适度补偿，但这些线粒体能够维持Δ p与急性暴露于高温，ROS的生产没有不同的驯化组之间，这表明这些增加线粒体的能力不改变线粒体的热敏感性。驯化到33摄氏度抑制线粒体呼吸作为一个结果的影响，对NADH脱氢酶（复合物I）。这些高温驯化的鱼仍然保持类似于其他驯化组的Delta p和ROS生产水平。这项工作表明，鳉鱼线粒体可以成功地适应广泛的温度，而不会引起重大的功能权衡在急性热变化和高温驯化的结果在抑制代谢，在有机体水平上观察到的模式一致。
Processes acting at the level of the mitochondria have been suggested to affect the thermal limits of organisms. To determine whether changes in mitochondrial properties could underlie shifts in thermal limits, we examined how mitochondrial properties are affected by thermal acclimation in the eurythermal killifish, Fundulus heteroclitus - a species with substantial plasticity in whole-organism thermal limits. We hypothesized that thermal acclimation would result in functional changes in the mitochondria that could result in trade-offs in function during acute thermal shifts. We measured the mitochondrial respiration rate ((V)over dot(O2)) through multiple complexes of the electron transport system following thermal acclimation (to 5, 15, 33 degrees C) and assessed maintenance of mitochondrial membrane potential (Delta p) and rates of reactive oxygen species (ROS) production as an estimate of costs. Acclimation to 5 degrees C resulted in a modest compensation of mitochondrial respiration at low temperatures, but these mitochondria were able to maintain Delta p with acute exposure to high temperatures, and ROS production did not differ between acclimation groups, suggesting that these increases in mitochondrial capacity do not alter mitochondrial thermal sensitivity. Acclimation to 33 degrees C suppressed mitochondrial respiration as a result of effects on NADH dehydrogenase (complex I). These high-temperature acclimated fish nonetheless maintained levels of Delta p and ROS production similar to those of the other acclimation groups. This work demonstrates that killifish mitochondria can successfully acclimate to a wide range of temperatures without incurring major functional trade-offs during acute thermal shifts and that high-temperature acclimation results in a suppression of metabolism, consistent with patterns observed at the organismal level.