THE ACTION OF SUBTILIN ON HEATED BACTERIAL SPORES

Abstract

During short heat treatments at 85 C or 100 C, spores of 11 of 14 strains tested were found to be more sensitive to subtilin and heat than to heat alone. Heat and subtilin need not be applied simultaneously, however, for heated spores of Bacillus subtilis A.T.C.C. 9524 retain increased subtilin-sensitivity for at least 22 days. Unheated spores are less sensitive to subtilin than heated ones. The effect of subtilin increases with concentration in the range of 2 to 20 ppm. Spores frequently survive incubation with subtilin under conditions unfavorable to germination but do not do so under conditions which promote germination. Nevertheless many spores begin the process of germination when suitable nutrients are supplied, irrespective of the presence of subtilin in a concentration sufficient to prevent vegetative growth and colony formation. Ungerminated spores adsorb subtilin from buffer. After they are treated with subtilin, only a few form colonies unless they are treated with trypsin (to inactivate the adsorbed subtilin) before they are placed where they can germinate. It is concluded that subtilin is adsorbed by ungerminated spores, but that spores are not affected by it unless they are placed in an environment which causes them to germinate.