title: Free-living nematodes Caenorhabditis elegans possess in their mitochondria an additional rhodoquinone, an essential component of the eukaryotic fumarate reductase system.
abstract: The respiratory chain of Caenorhabditis elegans was characterized in mitochondria isolated from aerobically grown nematodes. Nematode mitochondria contain ubiquinone-9 as a major component and rhodoquinone-9 as a minor component. The ratio of ubiquinone-9/rhodoquinone-9 is higher in C. elegans mitochondria than in mitochondria from second-stage larvae of Ascaris suum, the free-living stage of porcine gut-dwelling nematode. The individual oxidoreductase activities comprising succinate oxidase and the amount of substrate-reducible cytochromes are comparable to those of mitochondria from second-stage larvae of A. suum. The specific activity of fumarate reductase is lower in C. elegans mitochondria than in mitochondria from second-stage larvae of A. suum, but still higher than in mammalian mitochondria. These results indicate that the free-living nematode C. elegans is capable of synthesizing rhodoquinone, as distinguished from aerobic mammalian species, although its mitochondria appear more aerobic than A. suum larval mitochondria.
authors.affiliation: Department of Parasitology, Division of Biochemical Analyses, Central Laboratory of Medical Sciences, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan. stakamiy@med.juntendo.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Takamiya
authors.forename: T
authors.initials: T
authors.lastname: Matsui
authors.forename: H
authors.initials: H
authors.lastname: Taka
authors.forename: K
authors.initials: K
authors.lastname: Murayama
authors.forename: M
authors.initials: M
authors.lastname: Matsuda
authors.forename: T
authors.initials: T
authors.lastname: Aoki
mesh_terms: D000332:Aerobiosis; D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D004579:Electron Transport; D008928:Mitochondria / Q000378:metabolism*; D013053:Spectrophotometry; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D014451:Ubiquinone; D013385:Succinate Dehydrogenase; C003304:rhodoquinone