Reactive oxygen species and Ca are involved in cadmium-induced cell killing in yeast cells.

Cadmium (Cd) is one of the most toxic heavy metals. It is of great environmental concern and its toxicity has been investigated in a variety of cells. In this study, we elucidated the toxic effects of Cd in cells of yeast (Saccharomyces cerevisiae). Our results showed that Cd (0.05-5.0 mmol·L) significantly inhibited yeast cell growth, and the inhibitory effect was positively correlated with Cd concentrations. Cd caused loss of yeast cell viability in a concentration- and duration-dependent manner. Intracellular reactive oxygen species (ROS) and Ca levels increased in yeast cells after exposure to 5.0 mmol·L Cd for 6 h. Cd-caused cell viability loss was blocked by antioxidants (0.5 mmol·L ascorbic acid or 500 U·mL catalase) or Ca antagonists (0.5 mmol·L ethylene glycol tetraacetic acid or 0.5 mmol·L LaCl). Moreover, a collapse of mitochondrial membrane potential (ΔΨ) was observed in Cd-treated yeast cells. These results indicate that Cd-induced yeast cell killing was associated with the elevation of intracellular ROS and Ca levels and also the loss of ΔΨ.