STRUCTURE OF EXTRACELLULAR POLYSACCHARIDES SYNTHESIZED FROM SUCROSE BY NEISSERIA ISOLATED FROM HUMAN DENTAL PLAQUE

Five strains of Neisseria resembling N. mucosa and N. subflava, isolated from human dental plaque, synthesized extracellular polysaccharides from sucrose. Methylation analysis and characterization of the cleavage products by GLC mass spectrometry were the methods used. The polysaccharide material, isolated from a culture broth by high-speed centrifugation, was characterized as an .alpha.-glucan with predominantly (1 .fwdarw. 4) linkages, although 10-17% were (1 .fwdarw. 3) linkages and 5-9% branches linked to the 6-position. A modified Smith degradation suggested that the material consists of 2 polysaccharides, an amylopectin-type (major component) and an .alpha.-(1 .fwdarw. 3)-linked glucan. The mean MW of methylated material was 45,000-65,000.