title: Genetic transfer of Salmonella typhimurium and Escherichia coli lipopolysaccharide antigens to Escherichia coli K-12.
abstract: Escherichia coli K-12 varkappa971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv(+) hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his(+) (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F' factor (FS400) carrying the rfb-his region of S. typhimurium to the same two ilv(+) hybrids gave similar results. LPS extracted from two ilv(+),his(+), factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his(+) hybrids obtained from varkappa971 itself by similar HfrK9 and F'FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli varkappa971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli varkappa971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli varkappa971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his(+) recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Omega8. This suggests that, although the parental E. coli K-12 strain varkappa971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units.
mesh_terms: D000372:Agglutination Tests; D000918:Antibody Specificity; D000941:Antigens; D000942:Antigens, Bacterial; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003087:Colicins / Q000494:pharmacology; D003090:Coliphages; D003470:Culture Media; D004926:Escherichia coli / Q000032:analysis / Q000276:immunology*; D005827:Genetics, Microbial; D006824:Hybridization, Genetic; D008070:Lipopolysaccharides / Q000032:analysis; D012483:Salmonella Phages; D012486:Salmonella typhimurium / Q000032:analysis / Q000276:immunology*; D014161:Transduction, Genetic
chemical_list: D000941:Antigens; D000942:Antigens, Bacterial; D003087:Colicins; D003470:Culture Media; D008070:Lipopolysaccharides