Centre for Eukaryotic Evolutionary Microbiology, Biosciences, College of Life & Environmental Sciences, University of Exeter, UK.
J Eukaryot Microbiol. 2012 Mar-Apr;59(2):111-3. doi: 10.1111/j.1550-7408.2011.00605.x. Epub 2012 Jan 30.
Mitochondria have been put forward as the saviours of anaerobes when their environment became oxygenated. However, despite oxygenic photosynthesis evolving around 2.7 billion years ago (Ga), followed by the "Great Oxidation" of the atmosphere ~ 2.4 Ga, the deep oceans remained largely anoxic and either iron-enriched or sulphidic until 580 million years ago, when the eukaryotic radiation was well underway. Atmospheric oxygen probably remained at an intermediate concentration (1-10% of the present level) from ~ 2.4 until ~ 0.8 Ga when a "lesser oxidation" began. This drastically changes the textbook view of the ecological conditions under which the mitochondrial endosymbiont established itself. It could explain the widespread distribution of anaerobic biochemistry in every eukaryotic supergroup: anaerobic biochemistry is hard-wired into the eukaryotes.
线粒体被认为是当环境变得富含氧气时，厌氧生物的救星。然而，尽管大约 27 亿年前就已经进化出了有氧光合作用，随后大气中的“大氧化”发生在大约 24 亿年前，但是直到 5.8 亿年前，深层海洋仍然主要是缺氧的，要么富含铁，要么富含硫，此时真核生物的辐射已经在进行中。大气中的氧气含量可能在大约 24 亿年至 8 亿年前一直保持在一个中间浓度（目前水平的 1-10%），直到大约 8 亿年前开始了“较小的氧化”。这极大地改变了教科书上对线粒体内共生体确立自身所处的生态条件的看法。它可以解释为什么在每个真核超群中都广泛分布着无氧生物化学：无氧生物化学是真核生物的固有特征。
