title: Reactivity of lipopolysaccharides from various salmonella SR and R chemotypes Ra-Re mutants with concanavalin A.
abstract: Lipopolysaccharides from different R mutants of Salmonella minnesota and Salmonella typhimurium belonging to chemotypes Ra to Re, as well as from three SR mutants of Salmonella typhimurium were selected for a study of their precipitability with Concanavalin A. Predictions as to the outcome of the reaction could be made since both the chemical structure of the Salmonella R lipopolysaccharides and structural requirements for a positive reaction with Concanavalin A are well established. Precipitation studies in the immuno-electrophoretic assay and in the microcapillary test were carried out with alkali-treated lipopolysaccharides as untreated lipopolysaccharide is too highly aggregated to allow a sufficient migration in agarose layers. Lipopolysaccharides of all mutants--except the SR mutants--were obtained by the phenol/chloroform/petroleum ether method in order to avoid contaminations by glucans or glycogen which are known to occur in phenol/water extracted lipopolysaccharides and which would lead to erroneous results. Additional precipitation studies were carried out with two other lectins of different polysaccharide specificity: Wheat Germ Agglutinin and Soybean Agglutinin. As expected, lipopolysaccharides of chemotypes Ra, Rb1, and RcP- mutants reacted strongly with Concanavalin A, whereas no reaction was demonstrable with lipopolysaccharides of chemotypes Rb2, Rb3, Rd and Re mutants. The lipopolysaccharide of an RcP+ mutant unexpectedly failed to precipitate unless it was dephosphorylated with HF. This artificially prepared RcP-lipopolysaccharide showed a strong reaction, thus demonstrating that negative charges in the direct neighborhood of reactive sugar units as in RcP+ LPS may prevent precipitation with Concanavalin A. No reactivity demonstrable by precipitation could be obtained using either Wheat Germ Agglutinin or Soybean Agglutinin with alkali-treated lipopolysaccharide even of those chemotypes which had the supposedly reactive sugar in a terminal position, such as N-acetyl-D-glucosamine in Ra mutants (Wheat Germ Agglutinin) or D-galactose in Rb2 or Rb3 mutants (Soybean Agglutinin).
mesh_terms: D000116:Acetylgalactosamine / Q000032:analysis; D000117:Acetylglucosamine / Q000032:analysis; D003208:Concanavalin A; D006027:Glycosides / Q000032:analysis; D006601:Hexoses / Q000032:analysis; D007122:Immunoelectrophoresis; D037102:Lectins; D008070:Lipopolysaccharides / Q000032:analysis*; D009154:Mutation; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D011233:Precipitin Tests; D012475:Salmonella / Q000032:analysis*; D012486:Salmonella typhimurium / Q000032:analysis
chemical_list: D006027:Glycosides; D006601:Hexoses; D037102:Lectins; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial; D003208:Concanavalin A; D000116:Acetylgalactosamine; D000117:Acetylglucosamine