Effects of hyperthermia in Tetrahymena. I. Location of acid hydrolases and changes in cell structure. Expl Cell Res

The effects of hypothermia on Tetrahymena pyriformis (E) were studied. Protein synthesis was greatly inhibited at elevated temperatures (33.5-34”C), although the rate of protein turnover was not initially greater than in controls. There was no evidence that cellular lesions induced by temperature shock resulted from a solubilization of lysosomal enzymes. More than 80 % of both acid phosphatase and acid proteinase activity remained particle-bound, even in cells incubated at 34°C for prolonged periods. Ultrastructural studies revealed gross lesions in all types of cell organelles. These included a loss of tubules from mitochondria, disappearance of the rough endoplasmic reticulum, nuclear abnormalities, and a swelling of bodies tentatively identified as peroxisomes or primary lysosomes. Autophagic vacuoles which contained considerable membra-nous material seemed to accumulate during treatment, and membranous whorls and smooth-walled vesicles became quite common in the cytoplasm. Our studies are consistent with the suggestion [28] that, supraoptimal temperatures affect phospholipid-containing membranes in Tetrahymena. The ciliated protozoan, Tetrahymena pyriformis, has been widely used in studies dealing wit