Martinez Eloy, Hendricks Eric, Menze Michael A, Torres Joseph J
College of Marine Science, University of South Florida, Saint Petersburg, FL 33701, USA.
Department of Biological Science, Eastern Illinois University, Charleston, IL 61920, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2016 Jan;191:216-225. doi: 10.1016/j.cbpa.2015.08.008. Epub 2015 Aug 20.
Thermal regimes in aquatic systems have profound implications for the physiology of ectotherms. In particular, the effect of elevated temperatures on mitochondrial energy transduction in tropical and subtropical teleosts may have profound consequences on organismal performance and population viability. Upper and lower whole-organism critical temperatures for teleosts suggest that subtropical and tropical species are not susceptible to the warming trends associated with climate change, but sub-lethal effects on energy transduction efficiency and population dynamics remain unclear. The goal of the present study was to compare the thermal sensitivity of processes associated with mitochondrial energy transduction in liver mitochondria from the striped mojarra (Eugerres plumieri), the whitemouth croaker (Micropogonias furnieri) and the palometa (Trachinotus goodei), to those of the subtropical pinfish (Lagodon rhomboides) and the blue runner (Caranx crysos). Mitochondrial function was assayed at temperatures ranging from 10 to 40°C and results obtained for both tropical and subtropical species showed a reduction in the energy transduction efficiency of the oxidative phosphorylation (OXPHOS) system in most species studied at temperatures below whole-organism critical temperature thresholds. Our results show a loss of coupling between O2 consumption and ATP production before the onset of the critical thermal maxima, indicating that elevated temperature may severely impact the yield of ATP production per carbon unit oxidized. As warming trends are projected for tropical regions, increasing water temperatures in tropical estuaries and coral reefs could impact long-term growth and reproductive performance in tropical organisms, which are already close to their upper thermal limit.
水生系统中的热状况对外温动物的生理机能有着深远影响。特别是，高温对热带和亚热带硬骨鱼线粒体能量转导的影响，可能会对生物体性能和种群生存能力产生深远后果。硬骨鱼的全生物体上下临界温度表明，亚热带和热带物种不易受与气候变化相关的变暖趋势影响，但对能量转导效率和种群动态的亚致死效应仍不明确。本研究的目的是比较条纹银鲈（Eugerres plumieri）、白口鲷（Micropogonias furnieri）和卵形鲳鲹（Trachinotus goodei）肝脏线粒体中与线粒体能量转导相关过程的热敏感性，与亚热带尖吻鲈（Lagodon rhomboides）和蓝鳍金枪鱼（Caranx crysos）的热敏感性。在10至40°C的温度范围内测定线粒体功能，热带和亚热带物种的结果均显示，在低于全生物体临界温度阈值的温度下，大多数研究物种的氧化磷酸化（OXPHOS）系统的能量转导效率降低。我们的结果表明，在临界热最大值出现之前，氧气消耗与ATP产生之间的偶联丧失，这表明温度升高可能会严重影响每氧化一个碳单位产生ATP的产量。由于预计热带地区会出现变暖趋势，热带河口和珊瑚礁水温的升高可能会影响热带生物的长期生长和繁殖性能，而这些生物已经接近其热上限。
