Ionic germination of spores of Clostridium perfringens type A.

Abstract

Spores of Clostridium perfringens NCTC 8238 underwent so-called “ionic germination” under suitable conditions in aqueous solutions of either inorganic or organic salts. Chlorides of alkali metal ions except for Na+ were the most effective in inducing germination. Chlorides of alkali earth metal ions were effective to some extent, but those of heavy metal ions were rather inactive. Potassium salts of halogens, nitrogen, sulfur and phosphorus, as well as organic acids including fatty acids and polycarboxylic acids were also germinative. Preheating the spores at 80 C for 10 min was essential for rapid and complete germination by these salts. Maximum germination occurred at an incubation temperature of 40 C and at a fairly wide range of pH values (5.0–9.0). The germination was markedly inhibited by various uncoupling reagents such as carbonylcyanide m-chlorophenylhydrazone, pentachlorophenol, hexachlorophene (HCP), and dicumarol. This inhibition was reversible because removal of these reagents allowed germination to proceed. The inhibiting effect of HCP was highly dependent on pH, suggesting that a molecular dissociation of the reagent affects the inhibition. Furthermore, the inhibition of germination by HCP was competitively overcome at higher KCl concentrations. The possible mechanism of ionic germination and the inhibitory effect of uncouplers on the ionic germination are discussed.