Abstract
To clarify the trigger mechanisms of bacterial germination, the initial swelling of spores under various pH conditions was followed by measuring the spore volume for 1 hour by means of the Coulter Counter method. Rapid swelling during germination was observed in the spores which were pretreated with L-alanine for 10 min under a pH condition between 5 and 9. This rapid spore swelling under conditions in which spores were triggered to germinate within 10 min in the presence of L-alanine was inbibited by D-alanine. This inhibition was less when the spores were pretreated in a weak acidic condition than that under neutral or alkaline conditions. These results indicate that spores are committed to germinaing with L-alanine at pH 5 or pH 6 and that this commitment is not greatly inhibited by D-alanine.
Spores were pretreated at pH 5 and 6 for 0 to 10 min and then incubated with L-alanine under the same pH condition for a resting period (total 10 min) before D-alanine was added. The best spore swelling conditions at pH 5 and 6 were 2 min acid treatment plus 8 min incubation with L-alanine and 4 min acid treatment plus 6 min incubation with L-alanine, respectively.
