Construction of a sodA::luxCDABE fusion Escherichia coli: comparison with a katG fusion strain through their responses to oxidative stresses.

A recombinant bioluminescent Escherichia coli strain, EBHJ, (sodA::luxCDABE), containing the promoter for the manganese superoxide dismutase ( sodA) gene fused to the Vibrio fischeri luxCDABE operon, was successfully constructed and characterized. Redox-cycling agents, such as paraquat and chromium, strongly induced a sodA- regulated response in dose-dependent manners, resulting in an increase of the bioluminescence. In a comparison with an existing oxidative stress responsive strain, DPD2511 (katG::luxCDABE), which is sensitive to H(2)O(2), the mechanism of chemicals that cause oxidative damage was elucidated via the key transcriptional factors involved in induction of the sodA and katG promoters, i.e. SoxRS and OxyR, respectively. It was found that responses from the katG- and sodA-based strains were significantly different dependent upon the chemicals being tested. Therefore, EBHJ, alone or in parallel with DPD2511, can be used to characterize and monitor chemicals that cause oxidative damage.