Effect of levamisole on the synthesis of macromolecules in log phase and synchronized cultures of Tetrahymena pyriformis, GL.

The effects of levamisole on log phase and synchronized cultures of Tetrahymena pyriformis, strain GL, have been examined. At a dose of 100 mug/ml, DNA, RNA and protein syntheses were inhibited by 38%, 27% and 19%, respectively, in log phase cells, and by 21%, 50% and 47%, respectively, in synchronized cells. Lipid synthesis was only slightly inhibited (15%) at this same dose in synchronized cells. Results suggest that levamisole may act by directly inhibiting nucleic acid syntheses and the inhibition of protein synthesis may be secondary to this effect.