THE LOCATION OF 4 FIMBRIN-ENCODING GENES, AGFA, FIMA, SEFA AND SEFD, ON THE SALMONELLA-ENTERITIDIS AND OR SALMONELLA-TYPHIMURIUM XBAI-BLNI GENOMIC RESTRICTION MAPS/

Four fimbrin-encoding genes, fimA (type-1 or SEF21 fimbriae), agfA (th in aggregative or SEF17 fimbriae), sefA (SEF14 fimbriae) and sefD (SEF 18 fimbriae) from Salmonella enteritidis (Se) 27655-3b were located on to the XbaI-BlnI genomic restriction maps of Salmonella typhimurium (S t) LT2 and Se strains SSU7998 and 27655-3b. The XbaI or BlnI genomic f ragments carrying these genes were identified by hybridization with la beled oligodeoxyribonucleotides or fimbrin-encoding genes. The fimbrin -encoding genes were not encoded by the virulence plasmids, but were l ocated on chromosomal DNA fragments. The position of each gene on a gi ven XbaI fragment was determined by hybridization of a series of XbaI- digested genomic DNA samples from previously characterized Tn10 mutant s of Se and St with its respective probe. The fimA gene mapped near 13 centisomes (Cs) between purE884::Tn10 at 12.6 Cs (11.8 min) and apeE2 ::Tn10 at 12.8 Cs (12.3 min) beside the first XbaI site at 13.0 Cs in St or between purE884::Tn10 at 12.6 Cs and the XbaI site at 13.6 Cs in Se. The agfA gene mapped near 26 Cs between putA::Tn10 and pyrC691::T n10 in St, but near 40 Cs between pncX::Tn10 and the XbaI site at 43.3 Cs in Se. This difference in map position was due to the location of agfA near one end of the 815-kb chromosomal fragment inverted between Se and St. The sefA and sefD genes mapped precisely at 97.6 Cs in Se, but were absent from the genome of St LT2. To verify the mapping proce dures used herein, tctC was also mapped in both Salmonella serovars. A s expected, tctC mapped near 60 Cs in both Sr and Se, thereby confirmi ng previous studies.