title: Axenic growth up-regulates mass-specific metabolic rate, stress resistance, and extends life span in Caenorhabditis elegans.
abstract: Culture in axenic medium causes two-fold increases in the length of development and adult life span in Caenorhabditis elegans. We asked whether axenic medium imposes dietary restriction (ADR), and causes changes in metabolic activity and stress resistance. Eat mutants, which have a reduced food intake, were studied in parallel with wild-type worms to assess potential synergistic actions of axenic culture and food restriction. We found that axenic culture enhances metabolic activity as assessed by mass-specific oxygen consumption rate and heat production. Axenic culture also caused higher activities of the antioxidant enzymes superoxide dismutase and catalase, and led to increased resistance to high temperature, which was further exacerbated by mutation in eat-2. These results show that axenic medium up-regulates a variety of somatic maintenance functions including oxidative and thermal stress resistance and that food restriction due to axenic growth and to mutation in eat-2 are very similar but not identical.
authors.affiliation: Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Houthoofd
authors.forename: Bart P
authors.initials: BP
authors.lastname: Braeckman
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lenaerts
authors.forename: Kristel
authors.initials: K
authors.lastname: Brys
authors.forename: Annemie
authors.initials: A
authors.lastname: De Vreese
authors.forename: Sylvie
authors.initials: S
authors.lastname: Van Eygen
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Vanfleteren
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003470:Culture Media; D004435:Eating / Q000502:physiology; D001068:Feeding and Eating Disorders / Q000235:genetics / Q000503:physiopathology; D005508:Food Deprivation / Q000502:physiology*; D015801:Helminth Proteins / Q000235:genetics; D008136:Longevity; D009154:Mutation; D010101:Oxygen Consumption / Q000502:physiology*; D013312:Stress, Physiological / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D022722:Thermogenesis / Q000502:physiology*; D015854:Up-Regulation
chemical_list: D003470:Culture Media; D015801:Helminth Proteins; D002374:Catalase; D013482:Superoxide Dismutase