[New lambdoid Escherichia coli phages. I. Isolation, group immunity and recombination with lambda phage]

550 bacterial strains were isolated from sewage. 69 of them were lysogenic by phages active on Escherichia coli. The phages were divided into two groups on the basis of UV-inducibility, the ability to form plaques on Rep-E. coli mutants and particle morphology: lambdoid (23 phages) and related to P2 (46 phages). Hybrid phages isolated from the crosses of lambdoid phages with phage lambda harboured the region imm lambda and the gene of adsorption specificity from other parent. Ten groups of heteroimmune phages were found in the collection of new temperate phages are homoimmune with known phages: lambda, phi 80, phi 81, 434. Another 7 phages involved in 6 groups of immunity which were heteroimmune to known phages. Diversity of lambdoid phage genes determining the structure of repressor is discussed.