Olle Larm

Studies on the length of the side chains of the dextran elaborated by Leuconostoc mesenteroides NRRL B-512

Abstract The length of the side chains in dextran NRRL B-512 has been studied by sequential degradation. Selective removal of the terminal d -glucosyl groups was achieved by alkaline treatment of a methylated dextran in which the hydroxymethyl groups had been replaced by C-p -tolylsulfonylmethyl groups; the 6-hydroxyl group of the new terminal units thus formed is unsubstituted. The degraded material was subjected to a second degradation by using the same procedure. The reactions were followed by methylation and/or ethylation of the products, acid hydrolysis, and analysis of the resulting mixture of ethers by g.l.c.-m.s. As a result of these studies, it is concluded that about 40% of the side chains contain only one d -glucose residue, at least 45% are two d -glucose units long, and the rest (max. 15%) are longer than two such units.

The Pneumococcal Polysaccharides: A Re-Examination

Publisher Summary The pneumococcal polysaccharides and their antisera are used in the immunological characterization of other polysaccharides. Structural studies of these polysaccharides are of special importance, and this chapter summarizes the results of such studies. Studies of a great number of extracellular polysaccharides from Gram-positive and Gram-negative bacteria indicate that they are composed of oligosaccharide repeating-units. The synthesis of a bacterial polysaccharide requires a considerable number of highly specific enzymes, increasing in number with the complexity of the repeating unit. The purification of a pneumococcal polysaccharide may be difficult, and the polysaccharide material is sometimes contaminated by a cell-wall component known as the “C-substance.” The methods for structural analysis of polysaccharides are not always adequate, especially when results of quantitative significance are needed. Sometimes, it may even be difficult to obtain satisfactory, quantitative analysis of the component sugars. Furthermore, considering the importance of these compounds in immunochemistry further work in this field is needed.

Structural studies on pneumococcus type II capsular polysaccharide

Abstract The structure of the capsular polysaccharide of Diplococcus pneumoniae Type II has been investigated. Methylation analyses of the original polysaccharide and of a product obtained on mild, acid hydrolysis of the polysaccharide, together with the characterization of an aldobiouronic acid derived therefrom, have provided the essential information in this study. Possible structures for the capsular polysaccharide are discussed.