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.

Antimicrobial Activity of Chamomile Essential Oil: Effect of Different Formulations

“…The previously described protocol was adapted for peroxide [36,37] and superoxide anion radicals [34,38] with modifications. A positive control, Me (0.5 mmol/L as end concentration), C Pe , C T80 , C Et , Van (bacteria), and Cas (fungi) at their respective MEC 10 concentrations were used to treat the cell suspensions (~10 6 cells/mL) for an hour at 35 °C (bacteria) and 30 °C (fungi) in RPMI media.…”

The wide‐ranging phenotypes of ergosterol biosynthesis mutants, and implications for microbial cell factories

“…Recent studies utilizing chemical derivatives of AmB, membrane permeabilisation assays, ergosterol-binding assays, and nuclear magnetic resonance spectroscopy, have indicated that AmB mycotoxicity is relayed primarily through sequestration of ergosterol into cell surface aggregates (Anderson et al, 2014;Gray et al, 2012;Palacios, Dailey, Siebert, Wilcock, & Burke, 2011). Strains deficient in Erg5 (and to a much lesser extent Erg2, Erg4, or Erg6) have increased tolerance to AmB (Gazdag et al, 2014). It is plausible that in the strains with enhanced polyene tolerance, the drug has reduced affinity for the sterols present.…”

Alkyl hydroperoxide reductase from Bacillus aquimaris MKSC 6.2 protects Esherichia coli from oxidative stress

“…Overexpression of AhpF and AhpC in the t ‐butyl hydroperoxide treated cells was confirmed by SDS‐PAGE (data not shown). It has been reported that in S. cerevisiae incubated with t ‐butyl hydroperoxide the intracellular O 2 •− concentration was magnified 6.7‐fold in comparison to that of untreated yeast cells , and this treatment has influenced on the rigidity and fluidity of plasma membrane of Schizosaccharomyces pombe plasma membrane . Therefore, similar studies on the investigation of the level of O 2 •− and components of plasma membrane of E. coli with and without AhpCF overexpression upon treatment with t ‐butyl hydroperoxide are required in the future.…”

“…•À concentration was magnified 6.7-fold in comparison to that of untreated yeast cells [14], and this treatment has influenced on the rigidity and fluidity of plasma membrane of Schizosaccharomyces pombe plasma membrane [15]. Therefore, similar studies on the investigation of the level of O 2 •À and components of plasma membrane of E. coli with and without AhpCF overexpression upon treatment with t-butyl hydroperoxide are required in the future.…”