STRESS TOLERANCE IN A YEAST STEROL AUXOTROPH - ROLE OF ERGOSTEROL, HEAT-SHOCK PROTEINS AND TREHALOSE

The role of ergosterol in yeast stress tolerance, together with heat s hock proteins (hsps) and trehalose, was examined in a sterol auxotroph ic mutant of Saccharomyces cerevisiae. Ergosterol levels paralleled vi ability data, with cells containing higher levels of the sterol exhibi ting greater tolerances to heat and ethanol. Although the mutant synth esised hsps and accumulated trehalose upon heat shock to the same leve ls as the wild-type cells, these parameters did not relate to stress t olerance. These results indicate that the role of ergosterol in stress tolerance is independent of hsps or trehalose. (C) 1998 Published by Elsevier Science B.V. All rights reserved.