Bouchard Patrice, Guderley Helga
Département de Biologie, Université Laval, Québec, Canada, G1K 7P4.
J Exp Biol. 2003 Oct;206(Pt 19):3455-65. doi: 10.1242/jeb.00578.
The time course of changes in the properties of mitochondria from oxidative muscle of rainbow trout was examined during warm (15 degrees C) and cold (5 degrees C) acclimation. Mitochondrial oxidative capacities showed a biphasic response during thermal acclimation: at a given assay temperature, capacities first increased and then decreased during warm acclimation and showed the inverse pattern during cold acclimation. This was most apparent for maximal rates of state 3 oxygen consumption expressed per mg mitochondrial protein. Rates expressed per nmol ADP-ATP translocase (ANT) showed this pattern during cold acclimation. A biphasic pattern was also apparent for state 4 and oligomycin-inhibited (state 4(ol)) rates of oxygen uptake expressed per mg protein. Changes in states 4 and 4(ol) were smaller during cold than warm acclimation. Warm acclimation reduced the proportion of cytochrome c oxidase and citrate synthase needed during mitochondrial substrate oxidation. Phospholipid concentrations per mg mitochondrial protein changed little with thermal acclimation. Mitochondrial properties changed more quickly during warm than cold acclimation. While the biochemical modifications during thermal acclimation may eventually compensate for the thermal change, compensation did not occur at its onset. Rather, the initial changes of mitochondrial oxidative capacity in response to temperature change accentuated the functional impact of the thermal change, and prolonged exposure to the new temperature was required to attain a degree of thermal compensation.
研究了虹鳟氧化型肌肉中线粒体特性在温暖（15摄氏度）和寒冷（5摄氏度）驯化过程中的变化时间进程。线粒体氧化能力在热驯化过程中呈现双相反应：在给定的测定温度下，温暖驯化期间能力先增加后降低，而在寒冷驯化期间则呈现相反模式。这在以每毫克线粒体蛋白表示的状态3氧气消耗最大速率上最为明显。以每纳摩尔ADP - ATP转位酶（ANT）表示的速率在寒冷驯化期间呈现此模式。以每毫克蛋白表示的状态4和寡霉素抑制的（状态4(ol)）氧气摄取速率也呈现双相模式。寒冷驯化期间状态4和4(ol)的变化比温暖驯化期间小。温暖驯化降低了线粒体底物氧化过程中所需的细胞色素c氧化酶和柠檬酸合酶比例。每毫克线粒体蛋白的磷脂浓度随热驯化变化不大。温暖驯化期间线粒体特性变化比寒冷驯化期间更快。虽然热驯化期间的生化修饰最终可能补偿热变化，但在开始时并未发生补偿。相反，线粒体氧化能力对温度变化的初始变化加剧了热变化的功能影响，并且需要长时间暴露于新温度才能实现一定程度的热补偿。
