[Tyrosol--the autoregulatory d1 factor of the yeast Saccharomyces cerevisiae]

The autoregulatory d1 factor of the yeast, Saccharomyces cerevisiae, that induces the transition of vegetative cells into refractory resting forms, has been isolated from the cell-free culture medium as an individual crystalline compound. It has been shown to be 2-(4-hydroxyphenyl)ethane-1-ol which is also known as tyrosol. When added to the producer culture at 5-15 microM concentration, tyrosol stimulated the endogenous respiration of cells, but inhibited at 20-80 microM concentration. At 200-800 microM concentration, it induced the occurrence of resting forms. The action of tyrosol was not specific, for it also inhibited the cell respiration of the bacteria, Escherichia coli and Bacillus cereus, at 64-86 microM concentration.