Depression by miconazole of heat-induced respiratory-deficiency in Saccharomyces cerevisiae

Miconazole, at 0.2 microM, decreased, by two orders of magnitude, the specific mutation rate of Saccharomyces cerevisiae to respiratory-deficient mutants (petites), which had been induced at either 37 degrees C or 39 degrees C. Identical concentrations of ketoconazole did not change the mutation rate. The results fit in the mechanisms of action which have been proposed for imidazole antimycotics, and constitute further support for the hypothesis that the targets of thermal death, in petite-positive associately-profiled yeasts, lie in the mitochondria.