Effects of Dimethyl Sulfoxide on Tetrahymena pyriformis GL. Fine Structural Changes and Their Reversibility*

Abstract

Fine-structural changes are included in Tetrahymena by exposure to 7.5% dimethyl sulfoxide (DMSO) in the presence of growth medium. Some of these changes (nucleolar, mitochondrial, peroxisomal) resemble those seen during starvation, in agreement with the previously reported inhibitory effect of DMSO on food-vacuole formation, changes such as helical formations of polyribosomes indicate additional internal actions of the reagent. The effects vary to some extent within the same group of cells, suggesting that sensitivity to the reagent may differ with the stage in the cell cycle. The structural changes induced by a 1 h exposure to DMSO are reversible; recovery of the cells after removal of the reagent is slower than after starvation. The recovery may be associated with renewed synthesis.