[Electron microscopic study of Bacillus subtilis mutants differing in the serine proteinase activity and spectrum]

Vegetative cells and spores of the colonial morphological mutants of Bacillus subtilis A-50 were studied by electron microscopy. The ultrastructure of vegetative cells from both asporogenic colonial-morphological mutants and those which were capable of forming spores in the presence of high concentrations of nitrogen and carbon sources with a decreased activity and a modified spectrum of serine proteases differed from the parent strain by the presence of a microcapsule, the uneven thickness of a cell wall, and the absence of a distinct periplasmic space. Crystalline inclusions of a regular shape were detected in the sporeforming mutant in those cells which were devoid of spores. Spores of the mutant had additional layers.