title: O-antigen variation in Salmonella spp.: rfb gene clusters of three strains.
abstract: The O antigens of Salmonella serogroups A, B, and D differ structurally in their side-chain sugar residue. These genes encoding O-antigen biosynthesis are clustered in the rfb operon. We report here the molecular cloning and analysis of the rfb operons of Salmonella paratyphi A (serogroup A) and S. typhi (serogroup D). The regions of DNA nonhomology between the rfb operons of these serogroup A, B, and D representatives are identified, and the evolutionary derivation of serogroup A from a serogroup D progenitor is discussed.
mesh_terms: D000940:Antigenic Variation; D000942:Antigens, Bacterial / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003360:Cosmids; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics / Q000648:ultrastructure; D005798:Genes, Bacterial; D008854:Microscopy, Electron; D009693:Nucleic Acid Hybridization; D019081:O Antigens; D009876:Operon; D012475:Salmonella / Q000235:genetics* / Q000276:immunology; D012482:Salmonella paratyphi A / Q000235:genetics / Q000276:immunology; D012485:Salmonella typhi / Q000235:genetics / Q000276:immunology; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D019081:O Antigens; D004262:DNA Restriction Enzymes