[Effects of the gas phase of cigarette smoke on the induction of the petite colony mitochondrial mutation by ethidium bromide in yeast].

The induction of the mitochondrial 'petite' mutation (rho-) in haploid yeast (Saccharomyces cerevisiae) by ethidium bromide is reduced or even abolished if cells are also treated with the gas phase of cigarette smoke. This is observed not only in the case of simultaneous treatments but also when the two drugs are applied in succession.