Characterization of surface saccharides in two Corynebacterium diphtheriaestrains

Two Corynebacterium diphtheriae strains were analyzed by assays employing a battery of highly purified fluorescent lectins. From 22 lectins tested onl y seven with affinity to receptor molecules containing N-acetylglucosamine (D-GlcNAc), N-acetylgalactosamine (D-GalNAc), galactose (D-Gal), mannose-li ke (D-Man-like) and sialic acid residues showed positive fluorescent labeli ng. A higher reactivity of Triticum vulgaris (WGA), which binds to sialic a cid and/or beta-D-GlcNAc-containing residues, and Bandeiraea simplicifolia (BS-II), which recognizes alpha and beta-D-GlcNAc units, was shown by the s ucrose-fermenting strain. Ricinus communis (RCA-I), which recognizes D-Gal units in addition to both Glycine max (SBA) and Artocarpus integrifolia (Ja caline) agglutinins that bind to D-GalNAc-containing residues, reacted pref erentially with the sucrose-negative strain. Canavalia ensiformis (Con A), which recognizes D-Man-like receptors, reacted with both sucrose-fermenting and non-sucrose-fermenting C. diphtheriae biotypes. However, higher intera ction was observed with the nonsucrose-fermenting strain. Fluorescence of W GA binding was significantly decreased by neuraminidase treatment suggestin g the presence of an exposed sialic acid moiety on C. diphtheriae surfaces. Binding assay using radiolabeled [I-125]WGA essentially confirmed the lect in fluorescence studies. N-Acetylneuraminic acid moieties were detected in whole cell hydrolysates as assessed by thin-layer and gas-liquid chromatogr aphy. The data indicate differences on the cell surface saccharide ligands between the sucrose-fermenting and the non-sucrose-fermenting C. diphtheria e strains. (C) 1999 Federation of European Microbiological Societies. Publi shed by Elsevier Science B.V. Ail rights reserved.