<i>Schizosaccharomyces japonicus</i> has low levels of CoQ<sub>10</sub> synthesis, respiration deficiency, and efficient ethanol production

<p>Coenzyme Q (CoQ) is essential for mitochondrial respiration and as a cofactor for sulfide quinone reductase. <i>Schizosaccharomyces pombe</i> produces a human-type CoQ<sub>10</sub>. Here, we analyzed CoQ in other fission yeast species. <i>S. cryophilus</i> and <i>S. octosporus</i> produce CoQ<sub>9</sub>. <i>S. japonicus</i> produces low levels of CoQ<sub>10</sub>, although all necessary genes for CoQ synthesis have been identified in its genome. We expressed three genes (<i>dps1</i>, <i>dlp1</i>, and <i>ppt1</i>) for CoQ synthesis from <i>S. japonicus</i> in the corresponding <i>S. pombe</i> mutants, and confirmed that they were functional. <i>S. japonicus</i> had very low levels of oxygen consumption and was essentially respiration defective, probably due to mitochondrial dysfunction. <i>S. japonicus</i> grows well on minimal medium during anaerobic culture, indicating that it acquires sufficient energy by fermentation. <i>S. japonicus</i> produces comparable levels of ethanol under both normal and elevated temperature (42 °C) conditions, at which <i>S. pombe</i> is not able to grow.</p> <p><i>Schizosaccharomyces japonicus</i> and <i>Schizosaccharomyces pome</i> are distinct in mitochondrial-related functions.</p>