[Transgenosis with participation of plasmid RP1; indications of the presence of a "composit plasmid" in an interspecies hybrid of Escherichia coli].

One of the transconjugants (1-7) obtained by the authors earlier in the conjugation of Escherichia coli J-62 with Pseudomonas aeruginosa 1822, besides the plasmic RP1 has acquired the ability to grow without proline and tryptophan. The detailed analysis has shown that in the conjugation of the transconjugant 1-7 with different strains of E. coli the plasmic RP1 and chromosomal genes were transmitted together, but in transduction--by means of bacteriophage P1, independently of each other. The fertility was found only in the transductants carrying the plasmid RP1. This suggests that in the intergeneric conjugations the transmission of chromosomal genes may occur without any firm link with the plasmid (as in the case of "aggregated plasmids"). In E. coli cells these chromosomal fragments of Ps. aeruginosa apparently formed small nontransmissible replicons.