Structure of the major neutral oligosaccharide-alditols released from the egg jelly coats ofAxolotl maculatum. Characterization of the carbohydrate sequence GalNAc(ηl-4)[Fuc(αl-3)] GlcNAc(ηl-3 6)

Several O-linked oligosaccharides of the jelly coat surrounding the eggs of Axolotl maculatum were analysed by 1H-NMR spectroscopy. The four major oligosaccharide-alditols released by reductive η-elimination display either the Lewisx(Lex) determinant or the sequence GalNAc(ηl-4)[Fuc(αl-3)]GlcNAc This last structure has previously been characterized in allergenically active oligosaccharides isolated from the sea squirt H-antigen, and hi the N-linked glycans of Schistosoma mansoni and human urokinase. It represents the major carbohydrate chain found in A.macu-latum,the oviduct of which constitutes an excellent source of ηl-4-acetylgalactosaminyl transferase activity. Moreover, the carbohydrate chains isolated from A.maculatum are quite different from those found hi seven other amphibian species, in which the presence of species-specific material has been characterized. The role of carbohydrates appears more and more apparent during the fertilization process, and the diversity of the O-linked oligosaccharides supports such a biological role.