[Role of phage LØ7 lysogeny in genetic variability of Escherichia coli].

AIM: Determine the possibility of Iysogenization of Escherichia coli single strain DNA (ssDNA) by 1ø7 bacteriophage from the Microviridae family and determine the role of phage lø7 lysogeny in genetic variability of these bacteria. MATERIALS AND METHODS: A method of E. coli K12 lysogenization by phage lø7 was developed. A spot-test for the control of resistance of the obtained lysogens against phage lø7 and determination of lysogen lø7 spontaneous production was worked out. Criteria for phage lø7 identification, that is spontaneously produced by E. coli K12 lysogens, were proposed. A kit of isogenic E. coli strains, that vary by mutations in ptsI, ptsH and fruA genes, that code phosphoenolpyruvate (PEP): carbohydrate phosphotransferase system (PTS) proteins, was constructed. RESULTS: The ability of highly virulent bacteriophage lø7 to lysogenize E. coli was shown. A reduction of lø7 titers in ptsI, ptsH and fruA E. coli K12 mutants was demonstrated compared with titers in wild-type bacteria. Lytic bacteriophage lø7 was also able to lysogenize ptsI, ptsH and fruA mutants at a high frequency. Lysogens are resistant to phages lø7, phiX174 of Microvirus genus and spontaneously produce lø7. CONCLUSION: Bacteriophage lø7 of the Microviridae family is able to lysogenize E. coli K12 and vertically transfer genome of this lytic phage. As a result, lytic phage lø7 takes part in bacterial variability as a factor of lysogen selection in bacteria population corresponding to PTS mutants by phenotype.