Previous work in this laboratory (Foster and Heiligman, 1949a) indicated that a deficiency of inorganic ions may be a limiting factor in sporulation of aerobic bacilli in certain complex organic media. Attempts to circumvent these deficiencies by using more concentrated media were unsuccessful; there was less sporulation in the more concentrated media. This latter behavior had been noted by previous investigators (Williams, 1931; Tarr, 1932; Brunstetter and Magoon, 1932) who, without specific

more »

... idence, ascribed the superior sporogenesis in dilute media to the depletion of nutrients. Roberts and Baldwin (1942) found that peptone used in concentrations that failed to support sporulation would do so if the peptone was first treated with activated charcoal, kaolin, or ferric hydroxide. They stated (1942, p. 655), "It would seem that spore formation by Bacillus subtilis in Bacto-peptone water is inversely proportional to the concentration of either a nutrient factor (not total nutrients) or some factor directly inhibitory to the spore-forming process." They did not, however, go into the matter further. Evidence is now available supporting both possibilities suggested. The sporulation of BaciUus cereus and other aerobic bacilli is inversely proportional to the concentration of the "nutrient factor" alanine in a synthetic medium (Foster and Heiligman, 1949b) . Also, we have now demonstrated the presence of potent naturally occurring antisporulation factors in complex organic media, whose influence comes into play as the concentration of the medium is increased; these factors alone, and not the initial concentration of nutrients, appear to account for the reduced sporogenesis of such media. We have been able to effect a substantial concentration and purification of the antisporulation substance(s), and its removal from complex media results not only in a remarkable enhancement of sporulation but frequently in greater abundance of vegetative development. Isolation of the factor(s) and further chemical studies are in progress, and additional details of these aspects will be published later.