Effects of potassium and sodium ions on the killing action of a Pichia kluyveri toxin in cells of Saccharomyces cerevisiae.

Loss of viability of toxin-treated cells of Saccharomyces cerevisiae SCF 1717 could be prevented in the period before they altered physiologically if cells were incubated in media with a suitable concentration of potassium (0.08 to 0.13 M) and hydrogen ions (pH 6.2 to 6.7). Incorporation of higher amounts of potassium chloride in the media had a pronounced negative effect on cell survival, particularly when the pH of the medium was lowered. Replacement of KCl by NaCl in the plate media was even more deleterious to toxin-treated cells and, in contrast with potassium, low concentrations of sodium ions could not sustain recovery of cells. Complete recovery of a toxin-treated cell suspension required an incubation of 3 h in a suitable medium. The recovery process was blocked by cycloheximide.