PubMed:2620302 JSONTXT 23 Projects

Production and partial characterization of the extracellular polysaccharides from oral Streptococcus salivarius. The production of polysaccharides from sucrose by extracellular enzymes from oral Streptococcus salivarius isolates and the physico-chemical properties of water-insoluble products (IPs) were investigated. Extracellular enzymes from all the 18 strains tested produced insoluble alpha-D-glucans (IGs) as well as soluble beta-D-fructans, and formed adhering deposits on glass. Generally, the IPs (mostly IGs) of S. salivarius strains differed from the S. sobrinus IPs by (a) containing significant proportions of alpha-D-(1----4)-, in addition to alpha-D-(1----3)- and alpha-D-(1----6)-glucosyl linkages, and much higher proportions of alpha-D-(1----3) than alpha-D-(1----6) linkages, (b) being more susceptible to hydrolysis by mutanase than by dextranase, (c) possessing low or no streptococcal cell-agglutinating ability, and (d) showing weaker adhesion to a glass surface. The degree of the polysaccharide adherence differed greatly among the S. salivarius strains and, therefore, they were divided into three groups of adherence producers; heavy, moderate, and slight. The IPs of the three groups contained, generally in descending order, a higher proportion of higher-molecular-weight fractions, and consisted of higher proportions of IG containing higher proportions of -(1----6)-alpha-D and -(1----4)-alpha-D glucosyl linkages and (1----3,6) branches, but showed higher susceptibility to hydrolysis by mutanase as well as dextranase. Thus, the production and the properties of extracellular insoluble alpha-D-glucans from sucrose differ considerably between oral S. salivarius and cariogenic S. sobrinus.