Reference

Ethidium bromide mutagenesis in Saccharomyces cerevisiae: modulation by growth medium components

Ethidium bromide mutagenesis in Saccharomyces cerevisiae: modulation by growth medium components. Gardella, Roberta S.; MacQuillan, Anthony M. (Dep. Microbiol., Univ. Maryland, College Park, Md., USA). Mutat. Res., 46(4), 269-84 (English) 1977. CODEN: MUREAV. DOCUMENT TYPE: Journal CA Section: 3 (Biochemical Interactions) Interference in petite mutant induction was noted when yeast cells encountered K lactate [996-31-6] prior to, during, and following ethidium bromide (I) [1239-45-8] exposure; however, more pronounced influences were obsd. in the first 2 cases. Which parameters of mutagenesis were modified was dependent on the time of contact with the substrate. Screening of other respiratory substrates for their capacity to inhibit mutagenesis uncovered an equiv. capability for K pyruvate [4151-33-1] and a lesser but substantial role for EtOH [64-17-5]. The ionic compn. of K lactate was an important determinant in its inhibitory potential, whereas its metab. was found of little if any significance. In vitro complexing of the mutagen to DNA was strongly inhibited in the presence of K lactate. The ionic species K pyruvate and KCl possessed a similar capacity to hinder I-DNA complex formation. A correlation existed between the capability to inhibit binding in vitro and the ability to inhibit induction of the petite mutation. The assocn. between I and yeast mitochondria was also sensitive to the presence of K lactate. A demonstrable and reproducible decrease in the level of drug binding to the organelles, plus a substantial degree of protection from inhibition of O uptake by I were evidence that K lactate influenced I interaction with mitochondria. Because the eventual expression of I-induced mutations can be modified by a no. of cultural conditions, the use of I mutation data suffers a limited usefulness.