Optimisation of the BgaB reporter system: determination of transcriptional regulation of stress responsive genes in Bacillus subtilis.

We constructed and characterised a new system to determine transcriptional regulation of genes in Bacillus subtilis. The system is based on the B. stearothermophilus-derived beta-galactosidase BgaB. In contrast to the systems described up to now the BgaB protein is not degraded in response to environmental stresses. We optimised buffer conditions for BgaB assays and developed a protocol which allows measurement of BgaB activity without background problems. To test the system we determined induction of the B. subtilis clpC gene in response to stress. Induction of this gene in response to stress occurred as described.