POLYSACCHARIDES FROM THE ENVELOPES OF HETEROCYSTS AND SPORES OF THE BLUE‐GREEN ALGAE ANABAENA VARIABILIS AND CYLINDROSPERMUM LICHENIFORME1

Abstract

ABSTRACTThe polysaccharides from the envelopes of heterocysts of Cylindrospermum licheniforme Kütz., and of heterocysts and spores of Anabaena variabilis Kütz., like those from the differentiated cells of Anabaena cylindrica Lemm., have a 1,3‐linked backbone consisting of glucosyl and mannosyl residues in a molar ratio of approximately 3:1. As is the case with A. cylindrica the polysaccharides from A. variabilis and from the heterocysts of C. licheniforme have terminal xylosyl and galactosyl residues as side branches. In addition, the polysaccharide from C. licheniforme resembles that from A. cylindrica in having terminal mannosyl residues as side branches (absent from A. variabilis). The polysaccharides from A. variabilis resemble that from A. cylindrica in having glucose‐containing side branches (absent from the heterocyst polysaccharide from C. licheniforme), but in contrast to the polysaccharides from the other two species they also have terminal arabinosyl residues as side branches. All of the polysaccharides mentioned appear to be structurally related; we present tentative structures for those not previously investigated. In contrast, the envelope of spores of C. licheniforme contains only a largely 4‐linked galactan. The bulk of this envelope is not polysaccharide in nature, and contains aromatic groups.