RESUMO
DNA adduction in the model yeast Saccharomyces cerevisiae was investigated after exposure to the fungicide penconazole and the reference genotoxic compound benzo(a)pyrene, for validating yeasts as a tool for molecular toxicity studies, particularly of environmental pollution. The effect of the toxicants on the yeast's growth kinetics was determined as an indicator of cytotoxicity. Fermentative cultures of S. cerevisiae were exposed to 2 ppm of Penconazole during different phases of growth; while 0.2 and 2 ppm of benzo(a)pyrene were applied to the culture medium before inoculation and on exponential cultures. Exponential respiratory cultures were also exposed to 0.2 ppm of B(a)P for comparison of both metabolisms. Penconazole induced DNA adducts formation in the exponential phase test; DNA adducts showed a peak of 54.93 adducts/109 nucleotides. Benzo(a)pyrene induced the formation of DNA adducts in all the tests carried out; the highest amount of 46.7 adducts/109 nucleotides was obtained in the fermentative cultures after the exponential phase exposure to 0.2 ppm; whereas in the respiratory cultures, 14.6 adducts/109 nucleotides were detected. No cytotoxicity was obtained in any experiment. Our study showed that yeast could be used to analyse DNA adducts as biomarkers of exposure to environmental toxicants.
Assuntos
Benzo(a)pireno , Adutos de DNA , Poluentes Ambientais , Saccharomyces cerevisiae , Adutos de DNA/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Benzo(a)pireno/toxicidade , Benzo(a)pireno/metabolismo , Poluentes Ambientais/toxicidade , Poluentes Ambientais/metabolismo , Mutagênicos/toxicidade , Mutagênicos/metabolismo , DNA Fúngico/genética , Fungicidas Industriais/toxicidade , Fungicidas Industriais/metabolismoRESUMO
The aim of this study consisted to evaluate the impact of a pesticide (penconazole) on the growth kinetics and genotoxicity on two yeast strains (Saccharomyces cerevisiae and Metschnikowia pulcherrima). When the penconazole was added at different phases of the growth of M. pulcherrima, no effect was noticed on the kinetics of yeast growth but DNA adducts were observed when penconazole was added in the exponential phase. Increasing doses (1-15 maximum residue limit) of the pesticide added at the beginning of the fermentation did not induce DNA adducts while kinetics were affected.