title: Changes in antioxidant enzyme activities, fatty acid composition and lipid peroxidation in Daphnia magna during the aging process.
abstract: Age-related changes in the balance between endogenous pro-oxidative and antioxidative processes in the freshwater cladoceran Daphnia magna (Crustacea) were assessed. The activities of key antioxidant enzymes including catalase, superoxide dismutase and glutathione peroxidase and levels of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) were determined in eight age classes, covering juvenile, young and senescent adults. Age-related changes in fatty acid composition were also measured to examine the contribution of polyunsaturated fatty acids (PUFA) in the peroxidation status of animals. Biochemical responses depicted in this study demonstrated that age-related decline in survival was accompanied by increasing oxidative stress and oxidative damage. Enhanced oxidative stress in aging D. magna was suggested by the significant increase in the formation of lipid peroxides, and a concomitant reduction of unsaturated fatty acids of 20 or more carbon atoms. Because aging was accompanied by selective loss of key antioxidant enzymes and small changes in the amount of PUFA, the breakdown of antioxidant defences might have directly contributed to oxidative stress, membrane lipid peroxide and a decline of survival. Indeed, the results reported here, indicate that age-related increases of lipid peroxides were at least partially due to the functional imbalance of enzymatic antioxidant defences.
authors.affiliation: Laboratory of Environmental Toxicology (UPC), CN 150 Km 14.5, Terrassa 08220, Spain. barata@intexter.upc.es
authors.forename: Carlos
authors.initials: C
authors.lastname: Barata
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Navarro
authors.forename: Inma
authors.initials: I
authors.lastname: Varo
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Riva
authors.forename: Solayan
authors.initials: S
authors.lastname: Arun
authors.forename: Cinta
authors.initials: C
authors.lastname: Porte
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003621:Daphnia / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D017392:Thiobarbituric Acid Reactive Substances; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase