[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.

[The genetic transfer, heredity and phenotypic expression of plasmid RP4::Mu cts genes in Bacillus cereus].

The transcipients were obtained in intrageneric matings of E.coli donor harbouring the plasmid PR4::Mu cts 62 with Bac. cereus GP7 recipient cells with the frequency 10(-9).

[Change in the ultrastructure of the cell wall of Bacillus cereus, determined by RP4 MUCTS62 plasmid].

The influence of plasmid RP4 Mucts62, heterologous for B. cereus, on the growth rate of B. cereus strains GA 682 and 319 obtained in our earlier experiments and on changes in the ultrastructure of their cell walls in comparison with B.

[Effect of the molecular weight of DNA on the effectiveness of plasmid transformation of E. coli K12].

The level of plasmid transformation and transfection by the high molecular mass DNA was studied for Escherichia coli mutants having increased efficiency of plasmid transformation by low molecular mass DNA. Decreased level of plasmid transformation and transfection registered in some mutants as compared to the one in wild type strain suggests the specificity of Escherichia coli cells penetration for DNA of different molecular mass.