Sirikarn CharoenbhakdiThanittra DokpikulThanawat BurphanTodsapol TechoChoowong AuesukareeMahidol UniversitySouth Carolina Commission on Higher Education2018-12-112019-03-142018-12-112019-03-142016-05-01Applied and Environmental Microbiology. Vol.82, No.10 (2016), 3121-313010985336009922402-s2.0-84966573867https://repository.li.mahidol.ac.th/handle/20.500.14594/40959© 2016, American Society for Microbiology. During fermentation, increased ethanol concentration is a major stress for yeast cells. Vacuolar H+-ATPase (V-ATPase), which plays an important role in the maintenance of intracellular pH homeostasis through vacuolar acidification, has been shown to be required for tolerance to straight-chain alcohols, including ethanol. Since ethanol is known to increase membrane permeability to protons, which then promotes intracellular acidification, it is possible that the V-ATPase is required for recovery from alcohol-induced intracellular acidification. In this study, we show that the effects of straight-chain alcohols on membrane permeabilization and acidification of the cytosol and vacuole are strongly dependent on their lipophilicity. These findings suggest that the membrane-permeabilizing effect of straight-chain alcohols induces cytosolic and vacuolar acidification in a lipophilicity-dependent manner. Surprisingly, after ethanol challenge, the cytosolic pH in Δvma2 and Δvma3 mutants lacking V-ATPase activity was similar to that of the wild-type strain. It is therefore unlikely that the ethanol-sensitive phenotype of vma mutants resulted from severe cytosolic acidification. Interestingly, the vma mutants exposed to ethanol exhibited a delay in cell wall remodeling and a significant increase in intracellular reactive oxygen species (ROS). These findings suggest a role for V-ATPase in the regulation of the cell wall stress response and the prevention of endogenous oxidative stress in response to ethanol.Mahidol UniversityAgricultural and Biological SciencesBiochemistry, Genetics and Molecular BiologyEnvironmental ScienceImmunology and MicrobiologyArticleSCOPUS10.1128/AEM.00376-16