Derivation of an F-Merogenote and a φ80 High-Frequency Transducing Phage Carrying the Histidine Operon of Salmonella

Abstract

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 480. One of the Hfr strains was lysogenized with a heat-inducible, h mutant of X80, and from this strain a highfrequency transducing phage carrying the his genes and the gnd gene of Salmonella was isolated. MATERIALS AND METHODS Bacterial strains. The bacterial strains used are listed in Table 1. Strains with SB or TA numbers are from the collections of P. E. Hartman or B. N. Ames, respectively. All S. typhimurium strains are derivatives of LT2, except SB5404, which is a derivative of LT7. E. coli strain SB2201 was derived from E'36 (Table 1). E'36 was first deleted of the his genes by education with P2c5nipl (14; T. Blumenthal, Virology, in press), and then a lacderivative was selected on E M B lactose medium at 37 C. The resulting strain, SB2201, was found to be lacking hisG, hisD, hisA, hisI, and hisE gene activity by mating with hisS. typhimurium strains harboring F' E. coli his episomes mutated in these genes (8), and hence is presumably deleted for the entire his operon. It is also deleted for gnd (Table 3). SB2201, and also SB1541, contain UAG suppressors. Strains were cultured at 37 C, except for 480Ximm lysogens which were cultured at 30 C. E'36, X178, and X-33 were kindly supplied by William S. Reznikoff. Bacteriophage. P22L4 (27) was used for transduction of S. typhimurium, and P22H5 [v2 mutant of Zinder (33)] was used for testing strains for sensi-741

Genetic characterization of a phi80 transducing bacteriophage carrying the histidine operon of Salmonella typhimurium

“…Marker rescue analysis of strain XX27 also revealed the same pattern of missing phage genes as found for k80immXdhis. DISCUSSION c80immXdhis was obtained from a strain of E. coli that has an F-his-gnd factor from S. typhimurium inserted in the tonB region of the chromosome (22). The relative gene order of the transposed Salmonella his-gnd region of the strain has not been determined directly, but from the direction of transfer of chromosomal genes (22) is inferred to be gnd-his-EIFAHBCDGO-trp.…”

“…A 480 phage, carrying the his operon and gnd gene of Salmonella typhimurium, was isolated previously (22) by the method of directed gene transposition (11). In this communication the phage will be referred to as 4)80immXdhis.…”

“…MATERIALS AND METHODS Media. Minimal medium and growth supplements are as described previously (22). Gluconate minimal medium is E mineral salts medium (21) supplemented with 0.5% glucono-lactone (Fisher Scientific Co.).…”

“…Bacteria were grown at 350C except for AcI857h80h lysogens, which were grown at 32°C. 480 lysogens were induced by brief exposure of AM3 broth cultures to UV as described previously (22). XcI857h80h lysogens were induced by heating AM3 broth cultures at 42°C for 15 to 20 min.…”

Isolation of a hybrid F' factor-carrying Escherichia coli lactose region and Salmonella typhimurium histidine region, F42-400 (F' ts114 lac+, his+): its partial characterization and behavior in Salmonella typhimurium

“…We have isolated a fused F' factor (F42-400) carrying tsll4 and lac+ markers from E. coli episome F42-114 (17) and a his+ marker from S. typhimurium episome FS400 (63). In this paper we present data on its isolation, partial characterization, and interaction with the S. typhimurium chromosome.…”