Composition of the Gum Produced by Root Nodule Bacteria

Extracellular Polysaccharides of Rhizobium

“…Like the carbazole estimation of glucuronic acid, the anthrone estimation of glucose has the advantage that previous hydrolysis of the polysaccharide, with the dangers of destruction or incomplete hydrolysis, is not necessary. Hopkins, Peterson & Fred (1930) found with a lucerne organism that the uronic acid was 4-7 yo' of the gum (calculated on an ash-free basis); in two clover strains it was 2 2 4 5 % and in a pea strain, 19-22 %. The fact that their strain of Rhizobium melidoti (Wisconsin 100) yielded so much less uronic acid than the clover and pea strains provides a measure of agreement .with our own failure to find glucuronic acid in any of the seven strains of the same species.…”

The Possible Significance of Pectic Enzymes in Root Hair Infection by Nodule Bacteria

“…Some arguments in favour of this idea may be put forward. The rhizobia form abundant slime of a polyuronide nature which is chemically related to the Pneuniococcus polysaccharides (Hopkins, Peterson andFred 1930, Bray, Schliichterer andStacey 1944). Among these polysaccharides, there exists a great variation in antigenic properties and chemical structure (Heidelberger 1956).…”

Physiological Studies on Rhizobium

“…Georgi and Wilson (1933) concluded that most of the glucose carbon not appearing as carbon dioxide was transformed into gum. Hopkins, Peterson and Fred (1930) found this gum to consist largely of glucuronic acid.…”