Rhizobium radicicolum, polysaccharide

In a recent paper650 the relationships between Rhizobium radicicolum polysaccharides and those of pneumococcus are indicated by crossprecipitin reactions of the former with Types III and VI anti-pneumococcus horse sera. In addition, hydrolysis of the methylated polysaccharide of Rhizobium radicicolum yields equal amounts of 2,3,6-trimethyl-D-glucose, 2,3-dimethyl-D-glucose and 2,3-dimethyl-D-glucuronic acid.65 1 The minimum trisaccharide repeating unit consists, in part, of cello-biuronic acid, and may be represented ... 

By 1945, Stacey speculated about the possibility of a structural relationship between Pneumococcus capsular polysaccharides and those produced by other organisms. With Miss Schliichterer, he had examined the capsular polysaccharide of Rhizobium radicicolum. This polysaccharide gave a precipitin reaction in high dilution, not only with Type III Pneumococcus antiserum, but also mixed with antisera from other Pneumococcus types. The chemical evidence indicated that the polysaccharide resembled the specific polysaccharides of Types I and II Pneumococcus. A decade later, the acidic capsular polysaccharide from Azoto-bacter chroococcum, a soil organism, was studied. It, too, produced serological cross-reactions with certain pneumococcal specific antisera. Although the molecular structure of the polysaccharide was not established, adequate evidence was accumulated to show a structural relationship to Type III Pneumococcus-specific polysaccharide. This was sufficiently close to account for the Type III serological cross-relationship. 

Polysaccharides isolated from Rhizobium radicicolum and Azotobacter chroococcum cross-react in high dilution in horse anti-Pn III. Part of the structure of the Rhizobium polysaccharide bears a close resemblance to that of Sill, inasmuch as both contain cellobiouronic acid in their respective... 

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