THE USE OF LECTINS IN MONITORING DEGRADATION OF OLIGOSACCHARIDE CHAINS IN MUCIN BY ORAL STREPTOCOCCI

The ability to utilize mucin oligosaccharides as sources of carbohydra te and energy is believed to be an important mechanism in the ecology of oral streptococci. In this study we have used digoxigenin-labelled lectins of various specificities to monitor changes in the nonreducing end groups of oligosaccharide chains following their degradation by S treptococcus oralis Ny 586 and Streptococcus sanguis Ny 584. The react ion of degraded mucin with peanut lectin, that recognizes the core dis accharide Gal (1,3)GalNAc in O-glycans, revealed a more extensive degr adation of oligosaccharide by S. oralis than by S. sanguis. This corre sponds to better growth of S. oralis on the mucin. Analyses with Datum stramonium lectin showed that terminal Gal (1,4)GlcNAc, or GlcNAc (1, 4)GlcNAc moieties, in the oligosaccharides are attacked by both strain s. Reaction patterns with alpha-L-fucose-specific lectins indicated th at terminal fucose was released by S. oralis but not by S. sanguis. Th is was in accordance with sugar analyses which showed that approximate ly 40% of the fucose units were released. The results extend previousl y observed losses of sugars from oligosaccharide chains during growth of these organisms on mucin.