title: Endogenous promutagen activation in the yeast Saccharomyces cerevisiae: factors influencing aflatoxin B1 mutagenicity.
abstract: The formation of convertants, revertants and other types of mitotic segregants was induced in Saccharomyces cerevisiae D7 upon incubation with aflatoxin B1 (AFB1). The most distinct effects were observed for gene conversion to tryptophan prototrophy. The fact that different cytochrome P-450 inhibitors (ellipticine, penconazole and propiconazole as yeast-specific P-450 inhibitors) abolished the AFB1-induced mutagenicity indicates that activation of the promutagen AFB1 depends on the cytochrome P-450-catalyzed electron-transfer reactions. This hypothesis is further supported by the observation that the cytochrome P-450 content of yeast cells harvested at different phases during growth is directly correlated with their sensitivity for AFB1-induced tryptophan conversion.
mesh_terms: D016604:Aflatoxin B1; D000348:Aflatoxins / Q000378:metabolism / Q000494:pharmacology*; D001711:Biotransformation / Q000187:drug effects; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004352:Drug Resistance, Microbial; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D000348:Aflatoxins; D065607:Cytochrome P-450 Enzyme Inhibitors; D005656:Fungal Proteins; D003577:Cytochrome P-450 Enzyme System; D016604:Aflatoxin B1; D007213:Indomethacin