Comunicação ao CICTA2008 - V2O5 induced lipid peroxidation and CAT A activity, disturbe cell growth and mitochondrial NADH cytochrome c reductase activity on Saccharomyces cerevisiae UE-ME3

Abstract

Vanadium is a rare, soft, ductile grey-white element found combined in certain minerals and used mainly to produce certain alloys or as major trace element of fossil fuels. Vanadium oxide (V2O5) is used as a catalyst in manufacturing sulfuric acid and maleic anhydride and in making ceramics, being a pollutant watering redistributed around the environment. Research on biological influence of vanadium has gained major importance because it is well known that exerts potent toxic, mutagenic, and genotoxic effects on a wide variety of biological systems, including vanadium pentoxide, which has been classified as carcinogenic agent for humans. Consequently the aim of this work was to use a wine wild-type Saccharomyces cerevisiae UE-ME3 greatly resistant to metal stress, as eukaryotic model to evaluate its response to V2O5 in range concentration from 0 to 2 mM. Cells were grown to mid-exponential phase at 28ºC, in 250-ml flasks containing 100 ml of YEPD medium with 2% (w/v) of glucose. At mid-exponential phase were inoculated in the same condition in the absence or presence of V2O5, during 200 min. The cultures were used for biomass determination, by wet weight, and to obtain the post-peroxissomal pellet which was used for determination of CAT A according Beers and Sizer (1952) and mitochondrial NADH cit c reductase according to Tzagoloff, et al. (1975). The resulting supernatant was used for determination of MDA production by a fluorescence method according to Ghkawa, et al. (1979). Enzymatic activities and MDA level were compared by one-way ANOVA, followed by a Dunnett's test to identify significant differences (p<0.01). The effect on protein synthesis inhibition was also evaluated determining the dose-response curves in same liquid medium containing V2O5 at 0-2 mM and cycloheximide 50 mg/mL for 30 min. At the same time and conditions was performed a control assay without cycloheximide. Our results shows that V2O5, for 2.0 mM in culture media, induced in S. cerevisiae, a significant increase of lipid peroxidation and Catalase A activity and a decrease of wet weight and mitochondrial NADH cit c reductase. Also our results show that cicloheximide prevent cell death when cells grows 30 min in presence of 1.5 mM V2O5.