Differential response to isoproturon by two strains of Saccharomyces cerevisiae.

Abstract

S. cerevisiae UE-ME3 grown in MB medium in the absence and presence of IPU show a similar growth profile and a stabilization of the biomass, non-protein thiols content, cell viability (cfu) and cell redox status estimated by GSH/GSSG ratio. This response seems depend on GR and G6PD activities increase, which probably activates the glutathione cycle, signs of adaptive response to phenylurea. However, S. cerevisiae IGC-4072 strain showed signs of cell death in the presence of IPU, exhibiting a more slowly growth profile, a decrease of dry weight and cell viability, as well as a significant increase of free radicals scavenger (DPPH) in presence of phenylurea, without significant changes of the GSH/GSSG ratio. As the value of the GSH/GSSG ratio is significant lower in IGC-4072 cells and GR activity undergoes a marked decrease in the presence of the IPU it is suspected that the worst IPU adaptive capacity displayed by this strain depends on a poor antioxidant power mediated by the glutathione.