Characterization of surface saccharides in two Corynebacterium diphtheriae strains

Abstract

Two Corynebacterium diphtheriae strains were analyzed by assays employing a battery of highly purified fluorescent lectins. From 22 lectins tested only seven with affinity to receptor molecules containing N-acetylglucosamine ( d-GlcNAc), N-acetylgalactosamine ( d-GalNAc), galactose ( d-Gal), mannose-like ( d-Man-like) and sialic acid residues showed positive fluorescent labeling. A higher reactivity of Triticum vulgaris (WGA), which binds to sialic acid and/or β- d-GlcNAc-containing residues, and Bandeiraea simplicifolia II (BS-II), which recognizes α and β- d-GlcNAc units, was shown by the sucrose- fermenting strain. Ricinus communis (RCA-I), which recognizes d-Gal units in addition to both Glycine max (SBA) and Artocarpus integrifolia (Jacaline) agglutinins that bind to d-GalNAc-containing residues, reacted preferentially 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 interaction was observed with the non-sucrose-fermenting strain. Fluorescence of WGA binding was significantly decreased by neuraminidase treatment suggesting the presence of an exposed sialic acid moiety on C. diphtheriae surfaces. Binding assay using radiolabeled [ 125I]WGA essentially confirmed the lectin fluorescence studies. N-Acetylneuraminic acid moieties were detected in whole cell hydrolysates as assessed by thin-layer and gas-liquid chromatography. The data indicate differences on the cell surface saccharide ligands between the sucrose-fermenting and the non-sucrose-fermenting C. diphtheriae strains.