Inducible β-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.