title: Possible involvement of beta-lactamase in sporulation in Bacillus cereus.
abstract: Nonreverting beta-lactamase-negative strains were isolated from the beta-lactamase-constitutive strain, Bacillus cereus 569 H. These strains differed from both beta-lactamase-inducible and -constitutive strains not only in failure to produce beta-lactamase but also in failure to autolyze on aging, delayed sporulation, and failure to release free spores from sporangia when produced. The addition of B. cereus beta-lactamase of 15% purity to a final concentration of 10 IU/ml stimulates sporulation and particularly the release of free spores in culture from sporangia of strain 569 (inducible wild-type), 569/H (constitutive mutant of 569), and HPen(-), a nonreverting beta-lactamase strain isolated from 569/H in this laboratory. Cultures of HPen(-) did not release free spores without this treatment. Similar stimulation of sporulation and spore release by beta-lactamase from B. cereus were observed in another beta-lactamase-negative strain derived from 569/H as well as in certain sporogeny mutants of B. subtilis. The beta-lactamase preparation used in these experiments was free of peptidases, proteases, and autolysins capable of solubilizing wall from vegetative cells. These results, taken with our previous finding that a soluble peptidoglycan inducer becomes available in cultures of B. cereus only at sporulation and that normal derepression of beta-lactamase accompanies normal sporulation, suggest that beta-lactamase in B. cereus may be involved in peptidoglycan metabolism during sporulation and possibly the breakdown of sporangial wall with the concomitant release of mature spores.
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D005827:Genetics, Microbial; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D009154:Mutation; D010405:Penicillinase / Q000494:pharmacology*; D013170:Spores / Q000187:drug effects / Q000254:growth & development*
chemical_list: D010405:Penicillinase