Effect of “osmotic stabilizers” and glycerol on yeast cell envelopes

Abstract

Abstract The ultrastructure of cells of Saccharomyces cerevisiae and Schizosaccharomyces pombe was studied after their transfer to solutions of osmotic stabilizers used for maintenance of yeast protoplasts (0.7 m d‐mannitol, 0.7 m l‐rhamnose, and 0.6 m KCl). After 10 to 30 min incubation in these stabilizers significant changes appeared on the cell surfaces which progressed up to 60 min of incubation. The changes concerned especially the size, shape, and distribution of plasma membrane invaginations, which became deeper; in addition, large impressions were formed. Complementary changes were found in wall ridges which might result in formation of wall protrusions containing areas of separated cytoplasm. Similar changes of cell surfaces appeared after a short incubation of cells in 10% and 20% glycerol. The changes described are interpreted as a consequence of volume decrease and unbalanced cell wall synthesis after transferring the cells to media of higher osmolarity.