[The spore germination of "Clostridium tyrobutyricum" III.--An hypothesis on the mechanism of initiation (author's transl)].

Spores of C. tyrobutyricum do not contain 3-phosphoglyceric acid (PGA) but a polysaccharide which could replace PGA as an energy source during germination. The absence of PGA, which is an inhibitor of phosphotransacetylase, confirms the role of the acetyl-CoA synthesizing system in the germination initiated by acetate. Spore extracts of C. tyrobutyricum, as extracts of vegetative cells, were found to contain a ferredoxin and exhibited a NADH-ferredoxin oxydase activity which required the presence of an acetyl-CoA regenerating system, suggesting that this enzyme is also involved in germination. From this results, an hypothesis on the role of initiators (acetate and NH4+) in the mechanism of initiation of spore germination in C. tyrobutyricum is proposed. Acetate would have an effect on the utilisation of the endogenous polysaccharide and on glucose catabolism, and therefore, would be an effector for the production of the energy required particularly to transport cations into the spore.