Inducible beta-glucosidase synthesis during germination and outgrowth of Bacillus subtilis ATCC 9372 spores

AIMS: To investigate the role of germination processes in the expression of the beta-glucosidase enzyme in Bacillus subtilis ATCC 9372 spores. METHODS AND RESULTS: Enzyme activity was monitored in germinating and non-germinating spores of B. subtilis ATCC 9372. The expression of beta-glucosidase by spores of B. subtilis was further investigated in the presence of a germination inhibitor, d-alanine, and a transcription inhibitor, novobiocin. Detection of enzyme activity required the presence of the germinant, l-alanine, as well as the inducer, 4-methylumbelliferryl-beta-d-glucoside. Furthermore, beta-glucosidase synthesis was abolished in the presence of d-alanine or novobiocin. CONCLUSIONS: The data obtained in this study indicated that beta-glucosidase was not pre-existing, or merely attached to the spore, but was synthesized de novo during spore germination. SIGNIFICANCE AND IMPACT OF THE STUDY: The requirement of functional germination processes for the detection of beta-glucosidase activity makes this enzyme a good candidate for detection of spore viability.