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 anaerobicallygrown 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.

Mitochondrial and nuclear genomic integrity after oxidative damage in Saccharomyces cerevisiae

“…The above examples indicate a role for oxidantsensitive glycolytic enzymes in the cell's control of ROS production (42,43). This suggests that ROS directly feedback-inhibit metabolic pathways that support ROS production.…”