BACILLUS CEREUS SPORE GERMINATION - ABSOLUTE REQUIREMENT FOR AN AMINO ACID

The germination requirements of Bacillus cereus spores have been investigated. Spores of this organism have an absolute requirement for glycine or a neutral L-amino acid in order for germination to occur in the presence of purine ribosides. This requirement may be met by an endogenous pool of amino acids in certain spore crops so that addition of riboside alone initiates germination. The effectiveness of some amino acids in permitting germination in inosine decreases in the order L-alanine, L-α-amino-n-butyric acid, L-isoleucine, glycine, L-valine, L-serine, L-leucine. L-Alanine and some other amino acids alone can initiate germination but in this case the rate-limiting step differs from that involved in the stimulation of inosine germination by L-alanine. For germination in L-alanine alone Km is 500 μM, whereas in the presence of 0.1 mM inosine Km is 2.8 μM. L-Alanine germination is inhibited by D-alanine, but the stimulation of inosine germination by L-alanine is not. The results strongly suggest that L-alanine has two roles in B. cereus spore germination. © 1968.