FIELD: biotechnology, technology of recombinant DNAs. SUBSTANCE: E. coli cells are transformed with recombinant plasmids containing DNA fragment encoding immunity region of lambda phage with intact genes rex AB, ts 857, mutation in gene cz and mutation in structure part of gene cro that provides enhanced expression of genes rex AB lambda phage in plasmid composition as compared with lysogenic culture. Enhanced expression of genes rex AB inhibits the development of different bacteriophages in cells up to abortive infection occurring. Protective plasmid pIL 323 with replicon p15A of incompatibility group incY containing Bgl II-fragment of DNA in the region of lambda phage immunity is constructed. Recombinant plasmid pIL R8 and Bgl II-fragment of DNA are used as agents providing enhanced resistance to coli-phages. Method ensures to protect E. coli cultures producing proteins, hormones, essential amino acids and other bioactive substances against lysis and loss of the end products. EFFECT: enhanced resistance of E.coli cultures. 4 cl, 2 tbl
