Temperature-induced changes in fatty acid unsaturation of Tetrahymena membranes do not require induced fatty acid desaturase synthesis.

The usual rise in phospholipid-bound palmitoleic acid of Tetrahymena pyriformis cells slowly acclimating to low temperature exposure can be prevented by cycloheximide. This reduction in fatty acid desaturation is not caused by specific inhibition of a temperature-induced synthesis of a fatty acid desaturase but rather by a general effect equally conspicuous in isothermal cells. Cycloheximide-inhibited cells chilled and analyzed quickly, before long term ill effects of the drug are expressed, exhibit the rise in unsaturated fatty acids typical of temperature-acclimating cells.