Saccharomyces cerevisiae commits to a programmed cell death process in response to acetic acid

Recent evidence has revealed the occurrence of an apoptotic phenotype in Sa ccharomyces cerevisiae that is inducible with oxidative stress. Here, expos ure of S. cerevisiae to 20-200 mM acetic acid for 200 min at pH 3.0 resulte d in cell death. Yeast mortality induced by 120-200 mM acid was not inhibit ed by cycloheximide and was accompanied by ultrastructural alterations typi cal of necrosis. In contrast, alterations associated with cell death induce d by 20-80 mM acetic acid included: (i) cycloheximide-inhibitable chromatin condensation along the nuclear envelope; (ii) exposure of phosphatidylseri ne on the surface of the cytoplasmic membrane, revealed by the FITC-annexin V reaction; and (iii) the occurrence of DNA strand breaks, demonstrated by the TUNEL assay. These results show that a programmed cell death process s haring common features with an apoptotic phenotype can be induced by acetic acid in S. cerevisiae. This observation raises the possibility of this mod e of cell death being more generalized in yeasts than previously considered and extended to cell death induced by other stress agents.