Bacterial bioluminescent emission from recombinant Escherichia coli harboring a recA::luxCDABE fusion

This paper describes the quantitative evaluation of a bioluminescence assay for DNA damaging agents with respect to the linearity, sensitivity, specificity and dependence on the cell culture status. A recombinant bacterium, DPD2794, harboring a plasmid with a recA promoter fused to the luxCDABE operon, showed a very sensitive response to DNA-damaging stress. DPD2794 was found to show no noticeable response to non-mutagenic agents, i.e. phenol, except for some false responses appearing soon after injection. DPD2794 also showed a highly sensitive response to Mitomycin C, which was found to be a growth-stage-dependent response, not a growth-rate-dependent response. In addition, the relationship between the bioluminescence emitted in vivo, luciferase activity measured in vitro, and the amount of Lux proteins expressed was determined. The intensity of the bioluminescence emitted was found to be proportional to the luciferase activity in vitro, while the bioluminescence also seems to be correlated with the level of Lux proteins expressed in these Escherichia coli cells, up to 230 min post induction.