title: The surface structure seen on gonococci after treatment with CMP-NANA is due to sialylation of surface lipopolysaccharide previously described as a 'capsule'.
abstract: Phenotypic serum resistance of gonococci in urethral exudates is due to sialylation of lipopolysaccharide (LPS) by host cytidine 5'-monophospho-N-acetyl neuraminic acid (CMP-NANA). A surface structure was visible on gonococci [strain BS4 (agar)] that had been stained with ruthenium red after incubation with CMP-NANA. This structure was not visible after neuraminidase treatment, which released sialic acid but not LPS. The LPS profiles of strain BS4 (agar) had another in vivo-selected strain Gc40 (variant D1), were similar. A monoclonal antibody (mAb) which recognises epitope C on the LPS of 'capsulated' gonococci was shown by immunoblotting to react with several LPS components, including one of about 4.5 kDa which contains the probable site of sialylation by CMP-NANA. The reactions with the mAb were not affected by growing the strains with CMP-NANA nor by neuraminidase treatment of the sialylated LPS. The mAb also gold-labelled the surface of both strains before and after treatment with CMP-NANA. These data indicate that sialylation by CMP-NANA and staining with ruthenium red renders more visible the surface LPS which, sometimes in the past, has been seen as a 'capsule'.
authors.affiliation: Public Health Laboratory, Withington Hospital, Manchester, U.K.
authors.forename: A J
authors.initials: AJ
authors.lastname: Fox
authors.forename: A
authors.initials: A
authors.lastname: Curry
authors.forename: D M
authors.initials: DM
authors.lastname: Jones
authors.forename: R
authors.initials: R
authors.lastname: Demarco de Hormaeche
authors.forename: N J
authors.initials: NJ
authors.lastname: Parsons
authors.forename: J A
authors.initials: JA
authors.lastname: Cole
authors.forename: H
authors.initials: H
authors.lastname: Smith
mesh_terms: D000911:Antibodies, Monoclonal; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000378:metabolism*; D000939:Epitopes; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D019158:N-Acetylneuraminic Acid; D009344:Neisseria gonorrhoeae / Q000737:chemistry* / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D012430:Ruthenium Red; D012794:Sialic Acids / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D008070:Lipopolysaccharides; D012794:Sialic Acids; D012430:Ruthenium Red; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid