Cell-wall lytic enzymes at sporulation and spore germination in Bacillus species.

When washed sporulating cells of Bacillus cereus were incubated in buffer a t 37" in the presence of toluene, a partial autolysis occurred resulting in the freeing of mature and immature spores. The autolysate contained lytic enzymes which attacked vegetative cells and cell-wall preparations, releasing hexosaminecontaining peptides of characteristic constitution. The most active enzyme preparations were obtained from sporulating cells incubated for 1-2 hr. in buffer a t pH 5.06.0. Two water-soluble lytic systems, enzyme V and enzyme S with pH optima near 4-5 and 8.0 respectively, were separated from the autolysate. Enzyme S is probably identical with the lytic system present in spores of B . cereus and other Bacillus species and further observations on this system are described. When non-sporulating cells of B. cereus were incubated under similar conditions no obvious lysis or sporulation occurred and no cell-wall lytic activity could be demonstrated. In growing cultures of Bacillus cereus, considerable amounts of hexosamine-containing peptides were released into the medium during the period between the appearance of intracellular spores and free spores. It is suggested that enzyme V may be mainly concerned with the release of free spores from sporangia and enzyme S with the lytic processes which accompany spore germination.