ROLE OF PHAGE L07 LYSOGENY IN GENETIC VARIABILITY OF ESCHERICHIA COLI

Aim. Determine the possibility oflysogenization of Escherichia coli single strain DNA (ssDNA) by le7 bacteriophage from the Microviridae family and determine the role of phage le7 lysogeny in genetic variability of these bacteria. Materials and methods. A method of E. coli K12 lysogeniza-tion by phage le7 was developed. A spot-test for the control of resistance of the obtained lysogens against phage le7 and determination of lysogen le7 spontaneous production was worked out. Criteria for phage le7 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 le7 to lysogenize E. coli was shown. A reduction of le7 titers in ptsI, ptsH and fruA E. coli K12 mutants was demonstrated compared with titers in wild-type bacteria. Lytic bacteriophage le7 was also able to lysogenize ptsI, ptsH and fruA mutants at a high frequency. Lysogens are resistant to phages le7, phiX174 of Microvirus genus and spontaneously produce le7. Conclusion. Bacteriophage le7 ofthe Microviridae family is able to lysogenize E. coli K12 and vertically transfer genome of this lytic phage. As a result, lytic phage le7 takes part in bacterial variability as a factor of lysogen selection in bacteria population corresponding to PTS mutants by phenotype.

Escherichia coli, ptsH, ptsI, ssDNA bacteriophage le7, Microviridae family, lysogeny, Escherichia coli, phosphoenolpyruvate:carbohydrate phosphotransferase system, fruA, ptsH, ptsI mutants, genetic variability