Effect of phosphate limitation on the morphology and wall composition of Bacillus licheniformis and its phosphoglucomutase-deficient mutants.

Two very poorly lytic mutants of Bacillus licheniformis 6346 that had no teichuronic acid or glucose in their walls were phosphoglucomutase deficient. The walls of the mutants were less autolytic, and the lesion in the phosphoglucomutase gene and the formation of lytic amidase seemed to be interrelated. When phosphoglucomutase was regained or the effects of the deficiency were circumvented by the presence of galactose in the medium, the lytic enzyme was partially regained. When subjected to growth limitation by the supply of inorganic phosphate, the mutants ceased to make teichoic acid, and their walls contained a greatly increased proportion of mucopeptide. Under these conditions they formed irregular spheres which changed back to rods when inorganic phosphate was supplied. Both wall and protein synthesis were necessary for the changes in morphology. An intermediate crescent-shaped cell was formed in the change from sphere to a rod. The possible relationship of this morphological change to the distribution of biosynthetic sites is discussed.