Vanadium pentoxide: an oxidative stress agent which disturbs glutathione conjugates metabolization in Saccharomyces cerevisiae UE-ME3

Abstract

Under physiological conditions the vanadium can be detected in the oxidation state V (+5), a very toxic specie. In this study we used a wine wild-type Saccharomyces cerevisiae UE-ME3 to assess how eukaryotic cells respond to V2O5. Yeast cells in exponential phase were inoculated into YEPD medium with 2% (w / v) glucose and allowed to grow in the absence or presence of 0.5 to 2.0 mM V2O5 during 72 h. The results show that the cellular environment became more oxidizing, cell damages increase and failures in the transport and excretion of amino acids to the vacuole ocurr in yeast cells grown in the presence of vanadium (+5), as can be inferred by the decrease of GSH/GSSG ratio, increase of MDA cytoplasmic level and the sharp decrease of g-GT activity observed. Although there was an apparent response anti-stress to V2O5, reflected in an increase of GR activity in all trials of metal exposure and of GPx in cells exposed to 1.5 and 2.0 mM, this was probably mitigated by the decrease in activity G6PD and consequent availability of NADPH which compromise cell viability.