Adaptability of wine yeast to ethanol-induced protein denaturation

Abstract

This year marks the 200th anniversary of the birth of Dr. Louis Pasteur (1822–1895), who revealed that alcoholic fermentation is performed by yeast cells. Subsequently, details of the mechanisms of alcoholic fermentation and glycolysis in yeast cells have been elucidated. However, the mechanisms underlying the high tolerance and adaptability of yeast cells to ethanol are not yet fully understood. This review presents the response and adaptability of yeast cells to ethanol-induced protein denaturation. Herein, we describe the adverse effects of severe ethanol stress on intracellular proteins and the responses of yeast cells. Furthermore, recent findings on the acquired resistance of wine yeast cells to severe ethanol stress that causes protein denaturation are discussed, not only under laboratory conditions, but also during the fermentation process at 15°C to mimic the vinification process of white wine.

Selection of Ethanol Tolerant Strains ofCandida albicansby Repeated Ethanol Exposure Results in Strains with Reduced Susceptibility to Fluconazole

“…Little is known about how C. albicans responds to ethanol. In general, ethanol kills cells through disruption of the lipid bilayer [66,67], protein denaturation [68], and intracellular membrane perturbations [69]. There is thinning of the bilayer through direct interdigitation of ethanol between membrane lipids, and ultimately denaturation of the membrane which will result in cell death [66,67].…”

“…In general, ethanol kills cells through disruption of the lipid bilayer [66,67], protein denaturation [68], and intracellular membrane perturbations [69]. There is thinning of the bilayer through direct interdigitation of ethanol between membrane lipids, and ultimately denaturation of the membrane which will result in cell death [66,67]. Lipid metabolism alterations, aneuploidy, increased production of stress responsive genes, and drug efflux pump expression have all been shown to confer greater ethanol tolerance in S. cerevisiae [23,50,70].…”

“…This is likely due to protection from the impacts of ethanol perturbation on the plasma membrane. Models of yeast plasma membranes showed that increased ergosterol content in the membrane reduced ethanol interdigitation and contributed to resistance against the membrane thinning effect of ethanol [67,76]. This finding shows that at least part of the overlap of selective pressures between fluconazole and ethanol likely revolves around ergosterol.…”

“…We hypothesized that C. albicans utilizes multiple mechanisms to increase ethanol tolerance and improve survival when exposed to relatively high concentrations of ethanol. Ethanol affects many different pathways in cells such as protein folding, lipid bilayer integrity, and mitochondrial and nuclear function [71][72][73][74]81].…”

“…The similarities increase the likelihood that strains selected for higher ethanol tolerance will exhibit cross-tolerance/resistance to fluconazole. [66,67], protein denaturation [68], and intracellular membrane perturbations [69]. There is thinning of the bilayer through direct interdigitation of ethanol between membrane lipids, and ultimately denaturation of the membrane which will result in cell death [66,67].…”