CERTAIN FATTY-ACIDS AND STEROIDS PROTECT TETRAHYMENA FROM CELL-DIVISION STRESS CAUSED BY SHAKING

Cultures of Tetrahymena are routinely shaken to ensure proper access t o oxygen. Recent work showed that growth of dilute cultures (inocula < 10(4) cells ml-1) of T. pyriformis was sensitive to shaking. Addition of oleic acid (9 muM) or linoleic acid (140 muM) before or at the ons et of shaking gave considerable protection to the cells. A similar eff ect was seen with ergosterol (25 muM) and to some extent with choleste rol (100 muM). Octanoic acid (20 muM), palmitic acid (140 muM) and pal mitoleic acid (100 muM) had no effect. Paraquat (230 muM), which induc ed peroxidation of unsaturated fatty acids, increased the effect of sh aking-induced cell division stress. Such results may be due to changes in the membrane composition of Tetrahymena. It has not been possible to demonstrate differences in the C-14-oleic acid labelling of phospho lipids of cells with and without shaking.