Cell-Wall Lytic Enzymes at Sporulation and Spore Germination in Bacillus Species

Abstract

Cultures of B. cereus were grown in broth until spore release had begun. The cells were washed and reincubated in buffer (pH 5-6) with toluene, for 1 to 2 hours. Centrifugation removed the partially disintegrated cells leaving a supernatant containing cell-wall lytic enzymes. These enzymes attack vegetative cells and cell-wall preparations, with release of hexosamine containing peptides. Partial separation of two enzymes was achieved, based on their relative solubilities at pH 3. The pH 3 insoluble enzyme (S) appeared to be identical with the enzyme found in extracts of disintegrated spores of B. cereus and other Bacillus species. The action of both enzymes on heat-killed vegetative cells and cell walls resembled that of lysozyme. These enzymes play a definite part in sporulation and spore germination and it is suggested that the pH 3 soluble enzyme may be mainly concerned with the release of free spores from sporangia and enzyme S with the lytic processes which accompany spore germination.