[Effects of methyl mercuric chloride on growth inhibition and the cell membrane of Tetrahymena].

The effects of methylmercuric chloride (MMC) on the growth and cell membrane of the ciliate protozoan Tetrahymena pyriformis GL were studied. The compositions of fatty acids in the cell membrane lipids, which were extracted from cells cultured in medium containing MMC at 30 and 20 degrees C, were examined. As compared with control cells, 30 degrees C-cells were richer in saturated fatty acids than 20 degrees C-cell, indicating that the cell membrane of 30 degrees C-cells was rigid and that that of 20 degrees C-cells was mobile. When MMC was added to the culture media, the amount of unsaturated fatty acid in the cell membrane tended to decrease, resulting in an increase of rigidity of the cell membrane. When ergosterol was added to the media, the cell membrane became more rigid, and lipids were richer in saturated fatty acids. Ergosterol contributed to reduce the composition change due to addition of MMC to the media.