Effects of heat on the centrosomes of Chinese hamster ovary cells.

Chinese hamster ovary cells were heated either at 45.5 degrees for 15 min or at 42 degrees for 1 hr and then were either fixed immediately or allowed to recover at 37 degrees for intervals of up to 12 hr. In addition control cells and cells heated at 45.5 degrees for 15 min were immediately subjected to a cell fractionation procedure that yielded partially purified centrosome preparations. In 100% of the cells fixed and examined immediately after heating, the centrosomes were damaged. The osmiophilic cloud increased in density and became aggregated. The majority of the pericentriolar particles or virus-like particles disappeared, and in some cases the tubules of the wall of the centriole appeared disrupted. These changes were also noted in the much more abundant population of centrosomes in the partially purified cell fraction. Furthermore, in those cells heated at 45.5 degrees for 15 min, no recovery of the centrosomes or return of virus-like particles occurred even after incubation at 37 degrees for 12 hr.