Saccharomyces cerevisiae membrane sterol modifications in response to growth in the presence of ethanol

Abstract

Membranes isolated from yeasts grown in the presence of ethanol do not display the thermally induced transition in diphenylhexatriene anisotropy that is seen in control cells when they are exposed to ethanol in vitro. The total sterol content of the cells that were exposed to ethanol during growth is reduced, with no steryl esters being detected. A greater proportion of the total sterol pool is ergosterol in cells grown in the presence of alcohol. The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase is reduced by ethanol in vitro. Ethanol-exposed cells take up more exogenous sterol under aerobic conditions than do control cells. The presence of ethanol during growth reduces the activity of the plasma membrane enzyme, chitin synthase, as well as increasing the thermosensitivity of this enzyme.