FIG. 1.

Genomic organization of STE genes in S. enterica and positions of hybridization probes. The organization of the chromosomal regions of various STE genes was compared to that of the corresponding regions of the E. coli K-12 chromosome. Sequence data available for S. enterica serotypes Typhimurium and Typhi were obtained from the Genome Sequencing Center of Washington University and the Sanger Centre, respectively. Genes shared between E. coli and serovar Typhimurium or specific for one species are depicted by open and filled symbols, respectively. STE genes and genes with similarity to phage genes are shown by hatched and dotted symbols, respectively. The positions of the PCR fragments used as specific hybridization probes in this study are indicated. Probes were constructed by PCR with primers SifA-For-EcoRI and SifA-Rev-EcoRV (sifA), SifB-For-EcoRI and SifB-Rev-EcoRV (sifB), SseI2-For and SseI-Rev-EcoRV (sseI), and SseJ-For-EcoRI and SseJ-Rev-EcoRV (sseJ).