Ultrastructure of the cell wall of Schizosaccharomyces pombe following treatment with various glucanases.

The ultrastructure of isolated cell walls of Schizosaccharomyces pombe was studied by electron microscopy after treatment with the following purified enzymes: endo-beta-(1-->3)-glucanase, endo-beta-(-->6)-glucanase, and endo-alpha-(1-->3)-glucanase produced by Bacillus circulans; exo-beta-(1-->3)-glucanase and endo-beta-(1-->3)-glucanase produced by Schizosaccharomyces japonicus var. versatilis. The exo-beta-(1-->3)-glucanase had no detectable effect on the walls, but amorphous wall material was removed by action of the endo-beta-(1-->3)- and endo-beta-(1-->6)-glucanases of B. circulans to reveal a wall component consisting of densely interwoven microfibrils. The fibrils were hydrolyzed by treatment with the Schiz. japonicus endo-beta-(1-->3)-glucanase followed by B. circulans endo-alpha-(1-->3)-glucanase--suggesting that they were composed of -beta-(1-->3)-linked glucan and alpha-(1-->3)-linked glucan. The presence of a fibrillar component in untreated walls was evident after negative staining.