title: Antioxidant activity of L-ascorbic acid in wild-type and superoxide dismutase deficient strains of Saccharomyces cerevisiae.
abstract: Much has been published on the non-enzymatic antioxidant L-ascorbic acid (vitamin C), but even so its interaction with endogenous cellular defense systems has not yet been fully elucidated. Our study investigated the antioxidant activity of L-ascorbic acid in wild-type strain EG103 (SOD) Saccharomyces cerevisiae and isogenic mutant strains deficient in cytosolic superoxide dismutase (sod1delta), mitochondrial superoxide dismutase (sod2delta) or both (sod1delta sod2delta), metabolizing aerobically or anaerobically with and without the stressing agent paraquat. The results show that during both aerobic and anaerobic metabolism there was a significant increase in the survival of both wild-type S. cerevisiae cells and the mutant cells (sod1delta, sod2delta and sod1delta sod2delta) when pretreated with L-ascorbic acid before exposure to paraquat. Exposure to paraquat resulted in higher catalase activity but this significantly decreased when the cells were pre-treated with L-ascorbic acid. These results demonstrate that due to the damage caused by paraquat, the antioxidant protection of L-ascorbic acid seems to be mediated by catalase levels in yeast cells.
authors.affiliation: Laboratório de Genética Toxicológica, ULBRA, Canoas-RS, Brazil. jenifer.saffi@ulbranet.com.br
authors.forename: Jenifer
authors.initials: J
authors.lastname: Saffi
authors.forename: Luciano
authors.initials: L
authors.lastname: Sonego
authors.forename: Queli Defaveri
authors.initials: QD
authors.lastname: Varela
authors.forename: Mirian
authors.initials: M
authors.lastname: Salvador
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity; D050296:Microbial Viability / Q000187:drug effects / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010084:Oxidation-Reduction / Q000187:drug effects; D010269:Paraquat / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D006540:Herbicides; D024101:Mitochondrial Proteins; D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D002374:Catalase; D013482:Superoxide Dismutase; D010269:Paraquat; D001205:Ascorbic Acid