BIOLUMINESCENT ANALYSIS OF SOS RESPONSE I N ESCHERICHIA-COLI

We constructed a recombinant plasmid pPLS-1 to estimate the level of S OS 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 controll ed by the SOS promoter of gene cda from a plasmid ColD. The sequence b etween 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 substa nces was tested in E. coli strain C600(pPLS-1). The bioluminescent met hod proved to be very sensitive for estimating the level of SOS respon se. The results obtained by this method showed good correlation with r esults obtained by SOS Chromotest, umu-test, and Ames' test.