INHIBITION OF ERGOSTEROL BIOSYNTHESIS IS NOT ACCOMPANIED BY A CHANGE IN FATTY-ACID COMPOSITION IN SACCHAROMYCES-CEREVISIAE TREATED WITH THEANTIFUNGAL AGENT 6-AMINO-2-N-PENTYLTHIOBENZOTHIAZOLE

The antifungal agent 6-amino-2-n-pentylthiobenzothiazole at a concentr ation of 40 mu M lowered the specific growth rate of exponentially gro wing cultures of Saccharomyces cerevisiae by 36%. Treatment with 6-ami no-2-n-pentylthiobenzothiazole inhibited the biosynthesis of ergostero l and caused an accumulation of the methylated sterol precursors ergos ta-5,7-dienol and squalene, but had no significant effect on the compo sition and the rate of biosynthesis of fatty acids. The results indica te that neither the inhibition of ergosterol biosynthesis, nor the slo wing-down of culture growth by this antifungal agent, led to a compens atory alteration in the pattern of fatty-acyl chains in membrane lipid s. This finding contradicts the accepted wisdom for the action of a nu mber of antifungal agents.