Derivation of an F-merogenote and a phi-80 high-frequency transducing phage carrying the histidine operon os Salmonella.

An F' factor, FS400, carrying the his operon, the gnd gene, and the rfb gene cluster of Salmonella typhimurium was isolated. FS400 was introduced into an Escherichia coli strain having a lengthy deletion of the his gene region. From this strain, Hfr derivatives were isolated which had the F' factor integrated in the tonB locus near the attachment site of phi80. One of the Hfr strains was lysogenized with a heat-inducible, h mutant of phi80, and from this strain a high-frequency transducing phage carrying the his genes and the gnd gene of Salmonella was isolated.