Genetic map of Salmonella typhimurium, edition VIII

Abstract

We present edition VIII of the genetic map of Salmonella typhimurium LT2. We list a total of 1,159 genes, 1,080 of which have been located on the circular chromosome and 29 of which are on pSLT, the 90-kb plasmid usually found in LT2 lines. The remaining 50 genes are not yet mapped. The coordinate system used in this edition is neither minutes of transfer time in conjugation crosses nor units representing "phage lengths" of DNA of the transducing phage P22, as used in earlier editions, but centisomes and kilobases based on physical analysis of the lengths of DNA segments between genes. Some of these lengths have been determined by digestion of DNA by rare-cutting endonucleases and separation of fragments by pulsed-field gel electrophoresis. Other lengths have been determined by analysis of DNA sequences in GenBank. We have constructed StySeq1, which incorporates all Salmonella DNA sequence data known to us. StySeq1 comprises over 548 kb of nonredundant chromosomal genomic sequences, representing 11.4% of the chromosome, which is estimated to be just over 4,800 kb in length. Most of these sequences were assigned locations on the chromosome, in some cases by analogy with mapped Escherichia coli sequences.

The Salmonella selC locus contains a pathogenicity island mediating intramacrophage survival

“…The orf307 primer corresponded to a 21 bp portion of this segment that is 100% conserved between the Salmonella and E.coli K‐12 genomes. [Both mgtCB and selC map to the 82 minute region of the S.typhimurium chromosome (Sanderson et al ., 1995). ] When E.coli K‐12 DNA was used as template, the expected 2 kb PCR product was obtained; however, no fragment could be amplified with Salmonella DNA as template (data not shown).…”

“…Apart from hybridizing to the segment that is 100% conserved between the Salmonella 17 kb region of S.typhimurium, the 4 kb probe detected a and E.coli K-12 genomes. [Both mgtCB and selC map to second weak band in S.typhimurium that was similar in the 82 minute region of the S.typhimurium chromosome intensity to a single band detected in Citrobacter freundii (Sanderson et al, 1995).] When E.coli K-12 DNA was (data not shown).…”

A small protein that mediates the activation of a two-component system by another two-component system

“…Roland et al (1994) grew the bacteria under non-inducing conditions, and thus could only detect differences in polymyxin resistance when the pmrD gene was expressed from a plasmid vector. Likewise, the pmrA dependence of pmrD-mediated polymyxin resistance (Roland et al, 1994) re¯ects the fact that the PmrD Gene designations are as described (Sanderson et al, 1995).…”

Characterization of a bacteriocin produced by a clinical isolate of Shigella flexneri 2

“…Bacterial strains used in this work are listed in Table I, as described (Sanderson et al 1995). Shigella strains were isolated from fecal samples collected in the Centro Provincial de Salud Infantil "Eva Perón" from Santiago del Estero, the Hospital Interzonal Eva Peron from Catamarca and the Hospital del Niño Jesus from Tucumán, from the northwest region of Argentine.…”