Effects of tellurite on growth of Saccharomyces cerevisiae

The effects of potassium tellurite on growth and survival of rho(+) and rho(0) Saccharomyces cerevisiae strains were investigated. Both rho(+) and rho(0) strains grew on a fermentable carbon source with up to 1.2 mM K2TeO3, while rho(+) yeast cells grown on a non-fermentable carbon source were inhibited at tellurite levels as low as 50 mu M suggesting that this metalloid specifically inhibited mitochondrial functions. Growth of rho(+) yeast cells in the presence of increasing amount of tellurite resulted in dose-dependent blackening of the culture, a phenomenon not observed with rho(0) cultures. Transmission electron microscopy of S. cerevisiae rho(+) cells grown in the presence of tellurite showed that blackening was likely due to elemental tellurium (Te-0) that formed large deposits along the cell wall and small precipitates in both the cytoplasm and mitochondria.