Metal Ions - Comparative effects of NH4VO3 on detoxication enzymes and redox state of wine Saccharomyces

Abstract

The aims of this work was to compare the effects of NH4VO3, a pentavalent salt of vanadium, on cell viability, GST (EC 2.5.1.18) and -GT (EC 2.3.2.2) activities, and redox state of wild wine yeast Saccharomyces cerevisiae UE-ME3 and Saccharomyces chevalieri UE-ME1. Our results show that S. cerevisiae was more tolerant to NH4VO3 than S. chevalieri cells, which do not survive for concentration higher than 7.5 mM in culture medium, while S. cerevisiae cells remain viable in presence of 75 mM of ammonium metavanadate. In addition, we observed that values of GST activities and GSH/GSSG ratio in S. cerevisiae are higher than S. chevalieri, a good sign of strong antioxidant response has occurred in S. cerevisiae. Conversely the -GT activities level determined in S. cerevisiae were lower than in S. chevalieri. The ammonium metavanadate salt caused a significantly decrease (p<0,01) of GST and -GT activities in both yeast and a decrease of GSH/GSSG in S. cerevisiae. These facts suggest that ammonium metavanadate disturb the detoxycation capacity and protection mechanisms against oxidative stress of both yeast species mainly on S. chevalieri.