title: Differential effects of hydrogen peroxide and ascorbic acid on the aerobic thermosensitivity of yeast cells grown under aerobic and anoxic conditions.
abstract: We have previously demonstrated that in aerobically-grown cells of the yeast Saccharomyces cerevisiae, hydrogen peroxide (H(2)O(2)) increases and ascorbic acid decreases cellular thermosensitivity, as determined by the inducibility of a heat shock (HS)-reporter gene. In this work, we reveal that the aerobic thermosensitivity of anaerobically-grown yeast cells also increases in the presence of H(2)O(2), albeit differentially between cells with two different lipid profiles. In comparison to aerobically-grown fermenting cells treated with the same H(2)O(2) concentration, both these types of anaerobically-grown cells were found to be considerably less sensitive to aerobic heat shock and considerably more thermotolerant. Paradoxically, and in contrast to ascorbate-pretreated aerobically-grown yeast cells, when anaerobically-grown cells were heat-shocked aerobically in the presence of the same ascorbic acid concentration, they exhibited increased thermosensitivity and decreased intrinsic thermotolerance with respect to their untreated counterparts. These findings are discussed with respect to what is currently known about the redox and physiological status of yeast cells grown aerobically and cells reoxygenated following anoxic growth.
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, UK.
authors.forename: Christos
authors.initials: C
authors.lastname: Moraitis
authors.forename: Brendan P G
authors.initials: BP
authors.lastname: Curran
mesh_terms: D000222:Adaptation, Physiological; D000332:Aerobiosis; D000693:Anaerobiosis; D001205:Ascorbic Acid / Q000494:pharmacology*; D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D018869:Heat-Shock Response / Q000235:genetics; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D050296:Microbial Viability; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000235:genetics; D010100:Oxygen / Q000502:physiology*; D010101:Oxygen Consumption; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D006861:Hydrogen Peroxide; D001616:beta-Galactosidase; D001205:Ascorbic Acid; D010100:Oxygen