The Influence of Cations on Aerobic Sporogenesis in a Liquid Medium

Publisher Website
Google Scholar
Abstract
The in-fluence of the chloride salts of the univalent cations, Na, K, NH4 and Li (also Na lactate); the bivalent cations, Mg, Mn, Ba, Co, Pb and Ni; the trivalent cations Al, Ce, and Fe; and of the quadrivalent cation Sn on sporogenesis in a liquid medium was studied. 4 aerobic spore-formers, Bacillus subtilis, B. cereus, B. mesentericus and B. megatherium, were used. Definite molal concentrations of the above salts were placed in 1.0% peptone solution, inoculated with the organisms, and after 18 hrs. incubation, spore formation was determined by Anjeszky''s spore stain. The 3 molalities selected were (a) the one giving max. stimulation, (b) a molality at a point between max. viability and no growth due to toxic effect of salt, and (c) a molality at a point lower than that of max. viability due to insufficient stimulation caused by low salt concentration. The influence of pH on sporogenesis was also determined. Results showed that cations of univalent salts stimulated sporogenesis; cations of bi-, tri[long dash], and quadrivalent salts exerted no influence. Spore formation was most abundant at the point of max. stimulation. Within a favorable growing range, pH of medium did not materially affect spore formation. The molal concentrations at which max. stimulation occurred for the 4 organisms studied corresponded with that for Escherichia coli as previously determined by other investigators. This work, therefore, confirms and extends our knowledge of the physiological effect of cations on bacterial viability.