Hybridization increases mitochondrial production of reactive oxygen species in sunfish

Mitochondrial dysfunction and oxidative stress have been suggested to be possible mechanisms underlying hybrid breakdown, as a result of mito-nuclear incompatibilities in respiratory complexes of the electron transport system. However, it remains unclear whether hybridization increases the production of reactive oxygen species (ROS) by mitochondria. We used high-resolution respirometry and fluorometry on isolated liver mitochondria to examine mitochondrial physiology and ROS emission in naturally occurring hybrids of pumpkinseed (Lepomis gibbosus) and bluegill (L. macrochirus). ROS emission was greater in hybrids than in both parent species when respiration was supported by complex I (but not complex II) substrates, and was associated with increases in lipid peroxidation. However, respiratory capacities for oxidative phosphorylation, phosphorylation efficiency, and O2 kinetics in hybrids were intermediate between those in parental species. Flux control ratios of capacities for electron ...线粒体功能障碍与氧化应激被认为是杂种衰退的潜在机制，该现象由电子传递系统呼吸复合体的核质不相容所引发。然而，杂交是否会提升线粒体活性氧（ROS）的产生量，目前仍不明确。本研究采用高分辨率呼吸测定法与荧光光度法，对分离得到的肝线粒体进行检测，以探究南瓜籽太阳鱼（Lepomis gibbosus）与蓝鳃太阳鱼（L. macrochirus）天然杂交后代的线粒体生理状态及ROS释放情况。当以复合物I（而非复合物II）底物支撑呼吸时，杂交后代的ROS释放量高于两个亲本物种，且这一现象与脂质过氧化水平升高相关。不过，杂交后代的氧化磷酸化呼吸容量、磷酸化效率以及氧动力学参数均介于两个亲本物种之间。电子传递的通量控制比……