Microscale application of the SOS-LUX-TEST as biosensor for genotoxic agents Original Research Article

The bacterial biodetection system SOS-LUX-TEST has been developed for rapid detection of environmental genotoxins. This cellular bioassay is based on the receptor reporter principle with the SOS system as receptor sensitive to DNA damage and the bioluminescence system giving the optical signal which is registered by an appropriate detector. The lux-operon of a marine photobacteria (Photobacterium leiognathi) containing the whole information for the synthesis of the bacterial luciferase and its substrate was cloned downstream of a SOS-controlled promoter and introduced on a plasmid into E. coli. This system reacts in a dose-dependent manner with bioluminescence to any agent like radiation or chemicals which produce damages to the DNA molecules inside these cells. For the measurements of the genotoxic potential of chemical compounds a microplate luminometer was employed which allows continuous incubation and shaking during the registration of the signal. The kinetics of bioluminescence was always monitored over a period of at least 5 h. Typical model compounds with various DNA damaging potencies were tested.