Biochemical Studies on Germination of Bacterial Spores

The initiating mechanism in the germination of Bacillus thiaminolyticus spores was studied with 14C-L-alanine. A characteristic pattern of incorporation of L-alanine into the spores was observed during the early stages of germination with two incorporation peaks, one occurred just after contact with L-alanine (first incorporation) and the other 5 min later (second incorporation). L-Glutamine, L-valine, or L-serine substituted for the incorporation of L-alanine during the first stage of germination. Although, L-alanine taken up during the first incorporation phase was extractable with trichloroacetic acid (TCA), that taken up during the second incorporation phase was not extractable. The distribution of radioactivity showed that incorporated L-alanine was located in the spore coat, mainly in the paracrystal fraction. The radioactive material which remained in the germination medium or was extractable from the spore coat fraction with TCA treatment or pronase digestion was identified as alanine. Significance of incorporation of L-alanine and its location in the spore in reference to the initiation of germination is discussed.