[A kinetic method of determining the frequency of homologous recombination of plasmids in Escherichia coli cells].

To test the frequency of recombination by the RecF pathway the hybrid plasmids have been constructed which allow the bioluminescence recombination assay in the transformed E. coli cells. pF2(+) and pF6(+) are derivatives of pUC18 and pACYC184 respectively, with the luxA and luxB genes of Vibrio fischeri cloned downstream of the lac promoter. The luxA genes in pF2(+) and pF6(+) were mutated at the XhoI site and the HindIII site, accordingly, pF8 is a pACYC184 derivative with two copies luxA and luxB genes. The one copy of luxA gene was mutated at the XhoI site and another copy of the luxA gene was mutated at the HindIII site. A kinetic analysis of the population of the replicating and recombinating plasmids has been carried out. Experimental values of the frequency of recombination per one generation (P) were determined for the different E. coli strains.