title: Altered bacterial metabolism, not coenzyme Q content, is responsible for the lifespan extension in Caenorhabditis elegans fed an Escherichia coli diet lacking coenzyme Q.
abstract: Coenzyme Q(n) is a fully substituted benzoquinone containing a polyisoprene tail of distinct numbers (n) of isoprene groups. Caenorhabditis elegans fed Escherichia coli devoid of Q(8) have a significant lifespan extension when compared to C. elegans fed a standard 'Q-replete'E. coli diet. Here we examine possible mechanisms for the lifespan extension caused by the Q-less E. coli diet. A bioassay for Q uptake shows that a water-soluble formulation of Q(10) is effectively taken up by both clk-1 mutant and wild-type nematodes, but does not reverse lifespan extension mediated by the Q-less E. coli diet, indicating that lifespan extension is not due to the absence of dietary Q per se. The enhanced longevity mediated by the Q-less E. coli diet cannot be attributed to dietary restriction, different Qn isoforms, reduced pathogenesis or slowed growth of the Q-less E. coli, and in fact requires E. coli viability. Q-less E. coli have defects in respiratory metabolism. C. elegans fed Q-replete E. coli mutants with similarly impaired respiratory metabolism due to defects in complex V also show a pronounced lifespan extension, although not as dramatic as those fed the respiratory deficient Q-less E. coli diet. The data suggest that feeding respiratory incompetent E. coli, whether Q-less or Q-replete, produces a robust life extension in wild-type C. elegans. We believe that the fermentation-based metabolism of the E. coli diet is an important parameter of C. elegans longevity.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Saiki
authors.forename: Adam L
authors.initials: AL
authors.lastname: Lunceford
authors.forename: Tarra
authors.initials: T
authors.lastname: Bixler
authors.forename: Peter
authors.initials: P
authors.lastname: Dang
authors.forename: Wendy
authors.initials: W
authors.lastname: Lee
authors.forename: Satoru
authors.initials: S
authors.lastname: Furukawa
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Larsen
authors.forename: Catherine F
authors.initials: CF
authors.lastname: Clarke
mesh_terms: D000818:Animals; D001681:Biological Assay; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D008136:Longevity / Q000502:physiology*; D009154:Mutation; D014451:Ubiquinone / Q000378:metabolism
chemical_list: C104339:CLK-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D003470:Culture Media; D014451:Ubiquinone