REACTIVITY OF LIPOPOLYSACCHARIDES FROM VARIOUS SALMONELLA SR AND R (CHEMOTYPES RA-RE) MUTANTS WITH CONCANAVALIN-A

  • 1 January 1975
    • journal article
    • research article
    • Vol. 233  (3) , 327-334
Abstract
Lipopolysaccharides (LPS) from different R mutants of S. minnesota and S. typhimurium belonging to chemotypes Ra to Re, and from 3 SR mutants of S. typhimurium were selected for a study of their precipitability with concanavalin A. Precipitation studies in the immuno-electrophoretic assay and in the microcapillary test were carried out with alkali-treated LPs since untreated LPS is too highly aggregated to allow a sufficient migration in agarose. LPS of all mutants, except the SR mutants, were obtained by the phenol/chloroform/petroleum ether method to avoid contamination by glucans or glycogen which would lead to erroneous results. Additional precipitation studies were carried out with 2 other lectins of different polysaccharide specificity: wheat germ agglutinin and soybean agglutinin. LPS of chemotypes Ra, Rb1 and RcP- mutants reacted strongly with concanavalin A; no reaction was demonstrable with LPS of chemotypes Rb2, Rb3, Rd and Re mutants. The LPS of an RcP+ mutant unexpectedly failed to precipitate unless it was dephosphorylated with HF. This artificially prepared RcP- LPS showed a strong reaction, demonstrating that negative charges near reactive sugar units in LPS may prevent precipitation with concanavalin A. No reactivity demonstrable by precipitation could be obtained using wheat germ agglutinin or soybean agglutinin with alkali-treated LPS 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).