Changes in Ion Content in Heat-Treated Tetrahymena Cells

SYNOPSIS Changes in the amounts of Na⁺, K⁺, Mg²⁺ and Ca²⁺ were determined in the supernates of homogenized samples of Tetrahymena cells which were exposed to 7 heat shocks. The amounts of the same ions were also determined in the pH 4.5-soluble fractions after dialysis. During the last shock, i.e., 6.5 hr after the start of heat treatment, there was a change in the ion balance characterized by a gain in Na⁺, Ca²⁺ and non-dialyzable Mg²⁺ and a loss of K⁺. The change was not in phase with the synchronous cell division.