[Bioluminescent analysis of the SOS-response of Escherichia coli cells]

We constructed a recombinant plasmid pPLS-1 to estimate the level of SOS response in Escherichia coli by the bioluminescent method. A 6.7-kb promoterless operon of bioluminescence from Photobacterium leiognathi was cloned into a pBR322 vector, in which its expression was controlled by the SOS promoter of gene cda from a plasmid ColD. The sequence between the 5'-terminal Sph1 site of the operon and start codon ATG of the luxC gene was shown to be 56 bp in length and had no effect on the level of light emission. SOS-inducing potency of six mutagenic substances was tested in E. coli strain C600(pPLS-1). The bioluminescent method proved to be very sensitive for estimating the level of SOS response. The results obtained by this method showed good correlation with results obtained by SOS Chromotest, umu-test, and Ames' test.