[Effects of mercury compounds on growth, cell composition and glucose uptake in Tetrahymena pyriformis]

The effects of the mercuric compounds methylmercuric chloride (MMC) and mercuric chloride (MC) on growth, cell composition, and glucose uptake were studied in the ciliate protozoan Tetrahymena pyriformis GL. MMC was the most effective growth inhibitor of Tetrahymena among mercuric compounds and sulfhydryl inhibitors; it completely inhibited growth of Tetrahymena at concentrations of 1/30-1/3000 of the others. The growth inhibition of Tetrahymena was inversely proportional to concentrations of chemicals in medium. Particularly in the case of MMC and MC the relationship between the concentrations and growth were S-curved in shape. Contents of RNA and DNA in cells were shown to accumulate proportionally to the MMC concentration. Cell division was probably delayed by MMC. The value of the ratio of RNA to DNA content shown by DNA synthesis was inhibited more strongly than RNA at MIC/4 of MMC. MMC inhibited glucose uptake, and the inhibition was likely due to altered permeability of cell membranes. However, no difference was found in lipid compositions between control and MMC cells by thin-layer chromatography.