Recombinant Escherichia Coli Cells as Biodetector System for Genotoxins

Abstract

A bacterial biodetection system 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 as rapid optical reporter. Since the bioassay combines the SOS system with the bioluminescence system, we have termed it “SOS lux test”. For the SOS lux test, a recombinant plasmid pPLS1 (DSM 10333) was constructed in which the promoterless operon of bioluminescence of Photobacterium leiognathi 54D10 (lux C,D,A,B,F,E) (Krasnojarsk Institute of Biophysics Collection) is under control of a SOS promoter (part of the cda gene of the plasmid ColD, which carries a strong SOS promoter). This plasmid pPLS1 can be used to transform any Escherichia coli recA + system or other microorganisms with a SOS system, suitable for the detection of a specific genotoxic agent or combinations of genotoxic agents. The test system consists of recombinant bacterial cells in log-phase with pPLS1 that in response to the activity of a DNA damaging agent (e.g. chemicals, biotoxins or radiation) induce their SOS system and thereby the expression of the bioluminescence operon. The level of SOS response is quantified by measuring the light emission of the cells during their growth after treatment with the genotoxin. Compared with other bacterial bioassays based on the SOS response, such as the SOS chromotest or the umu test, the SOS lux test shows similar sensitivity.KeywordsGenotoxic PotentialBioluminescence SystemMutagenic PotencyluxAB GeneRelative Cell DensityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.