title: tert-Butyl hydroperoxide-induced differing plasma membrane and oxidative stress processes in yeast strains BY4741 and erg5Δ.
abstract: The molecular mechanism of tert-butyl hydroperoxide (t-BuOOH) elicited cytotoxicity and the background of t-BuOOH sensitivity were studied in the Saccharomyces cerevisiae ergosterol-less gene deletion mutant erg5Δ and its parental strain BY4741. In comparison to BY4741, untreated erg5Δ cells exhibited alterations in sterol and fatty acid compositions of the plasma membrane, as reflected by the inherent amphotericin B resistance, an elevated level (31%) of plasma membrane rigidity and a decreased uptake of glycerol. Surprisingly, the untreated erg5Δ cells exhibited an unbalanced intracellular redox state, accompanied by the continuous upregulation of the antioxidant enzymes Mn superoxide dismutase, catalase, and glutathione S-transferase, which resulted in decreased specific concentrations of superoxide and peroxides and elevated levels of the hydroxyl radical and thiols. The 2.5-fold sensitivity of erg5Δ to t-BuOOH suggested that the oxidative stress adaptation processes of the mutant could not restore the redox homeostasis of the cells and there is an overlap between sterol and redox homeostases. t-BuOOH treatment of both strains induced adaptive modification of the sterol and fatty acid compositions, increased the plasma membrane fluidity and elevated the specific activities of most antioxidant enzymes through specific regulation processes in a strain-dependent manner.
authors.affiliation: Faculty of Sciences, Department of General and Environmental Microbiology, University of Pécs, Pécs, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Gazdag
authors.forename: Gábor
authors.initials: G
authors.lastname: Máté
authors.forename: Milan
authors.initials: M
authors.lastname: Certik
authors.forename: Katalin
authors.initials: K
authors.lastname: Türmer
authors.forename: Eszter
authors.initials: E
authors.lastname: Virág
authors.forename: István
authors.initials: I
authors.lastname: Pócsi
authors.forename: Miklós
authors.initials: M
authors.lastname: Pesti
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D017353:Gene Deletion; D005990:Glycerol / Q000378:metabolism; D008560:Membrane Fluidity; D018384:Oxidative Stress; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D013261:Sterols / Q000032:analysis; D013312:Stress, Physiological; D020122:tert-Butylhydroperoxide / Q000633:toxicity*
chemical_list: D005227:Fatty Acids; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D003577:Cytochrome P-450 Enzyme System; D020122:tert-Butylhydroperoxide; C066577:ERG5 protein, S cerevisiae; D005990:Glycerol
keywords: Erg5Δ; Ergosterol; Oxidative stress; Plasma membrane; Tert-butyl hydroperoxide