Structure and biodegradation of the polysaccharide components of egg masses isolated from snails of an Ampullarius species

A polysaccharide preparation, isolated from egg masses deposited by snails of an Ampullarius species, was purified via precipitation with Cetavlon in the presence of sodium borate, and found to contain d-galactose and a smaller proportion of d-glucose, and to have two components with sedimentation coefficients of 10S and 40S. A polysaccharide, isolated from freshly laid egg masses, was highly branched and was shown to contain nonreducing α-d-glucopyranosyl and β-d-galactopyranosyl end-groups, and 3,6-di-O-substituted β-d-galactopyranosyl residues. One or more of the polysaccharide components was a d-glucopyrano-d-galactopyranan with non-reducing α-d-glucopyranosyl end-groups (1→4)-linked to β-d-galactopyranosyl residues. The polysaccharide preparations, obtained from freshly laid egg masses and from those that were left for 10 and 15 days after being laid, were structurally different from each other. With the passage of time, progressive diminution of the 10S component and the proportion of d-glucose in the polysaccharide took place, suggesting that each constituent was consumed preferentially by the snail embryos as an energy source.