The Effect of Strontium Stress to Yeast Cell Antioxidant Enzyme Activities under Acute Conditions

The malonaldehyde (MDA) and three antioxidant enzymes activity changes of yeast (Saccharomyces cerevisiae) have been investigated under strontium acute stress to explore the cell tolerance mechanism to strontium stress in this research. The results showed that: 1) The low concentration strontium did not lead visible oxidative damage. 2) Yeast cell may be affected by oxidative stress and lead to oxidative damage of membrane lipid as a results of the increase of MDA contents under middle strontium concentration short time stress conditions, then the cell would be induced to increase the antioxidant enzyme activity to scavenge the oxidative stress as a result of decrease of MDA contents with the culture time prolonging. The antioxidant enzymes induce mode was different to other heavy metals. 3) The high concentration strontium stress may inhibit the antioxidant enzyme activity and lead to irreversible oxidative damage as a result of great increase of MDA contents. We suggested that yeast cell tolerance mechanism to strontium under acute stress conditions were: 1) the low strontium stress may induce cell to increase the antioxidant enzyme activity to scavenge oxidative damage and 2) the high concentration strontium may form precipitate with cell membrane or culture medium to avoid acute lethal action to yeast cell under acute stress conditions but it yet will lead to irreversible oxidative damage.