GROWTH AND SPORULATION CHARACTERISTICS OF AN ORGANIC SULFUR-REQUIRING AUXOTROPH OF BACILLUS CEREUS.

Lundgren, D. G. (Syracuse University, Syracuse, N.Y.) and K. F. Bott. Growth and sporulation characteristics of an organic sulfur-requiring auxotroph of Bacillus cereus. J. Bacteriol. 86:462-472. 1963.-This paper reports investigations of several aspects of growth and sporulation of an organic sulfur-requiring auxotroph of Bacillus cereus ATCC 4342. The wild type and B. cereus T were also studied for comparative purposes. Growth of the mutant on minimal medium plus methionine was normal, but sporulation was completely inhibited. Some reaction involved in vegetative-cell maturity was probably blocked at a point just prior to the "triggering" of sporulation, since abnormally large amounts of poly-beta-hydroxybutyric acid (PHB) were formed. Growth of the mutant in the presence of cystine or cysteine was also accompanied by the build-up of large amounts of PHB, but some endospores were formed (approximately 5% by 72 hr). Results of dipicolinic acid (DPA), calcium, and heat-resistance studies revealed that the few spores formed by the auxotrophic mutant when grown on cysteine were somewhat below wild-type strains in their development of heat resistance, and considerably lower in content of Ca and DPA. This was not the case with spores formed in cells grown on cystine; heat resistance compared favorably with wild-type spores, but the Ca and DPA levels were lower.