title: [Characteristics of hybrid plasmids carrying the genes of colicinogenic plasmid Collb-P9 responsible for colicin Ib synthesis and inhibition of phage T5 development].
abstract: The EcoRI and HindII restriction endonucleases and pBR325 vector plasmid were used to obtain a set of hybrid plasmids containing ColIb-P9 fragments carrying the characters for colicin Ib synthesis and immunity and the ability to inhibit T5 phage growth. The genes responsible for colicin synthesis and immunity are closely linked and localized in the EcoRI fragment with a molecular weight of 1.85 MD (pIV41) or in the HindII fragment of 2.4 MD (pIV1). The clones containing these plasmids show an increased level of both spontaneous and mitomycin C-induced colicin synthesis and an increased level of immunity due to a larger dosage of the genes. The genes controlling T5 growth inhibition are localized in other restriction fragments of ColIb DNA: the EcoRI fragment of 1.45 MD (pIV7) and the HindII fragment of 4.3 MD (pIV5). We have demonstrated by means of hybrid plasmids that T5 growth inhibition is not connected with the colicin Ib synthesized in infected cells and is controlled by other specific product(s) of the ColIb plasmid genes. T5 phage growth was as efficient in clones containing plasmids with cloned colicin Ib genes as in a strain without plasmids. An investigation of the expression of the genes inhibiting T5 phage growth in an in vitro protein synthesis system has revealed a protein with a molecular weight of 36 000 which seems to take part in the process.
mesh_terms: D003001:Cloning, Molecular / Q000187:drug effects; D003087:Colicins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D004262:DNA Restriction Enzymes / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D005798:Genes, Bacterial / Q000187:drug effects*; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization / Q000187:drug effects*; D010957:Plasmids / Q000187:drug effects*; D013604:T-Phages / Q000235:genetics*
chemical_list: D003087:Colicins; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes
vernacular_title: Kharakteristika gibridnykh plazmid, nesushchikh geny kolitsino-gennoĭ plazmidy Collb-P9, otvetstvenny za sintez kolitsina Ib i podavlenie razvitiia faga T5.