A wide diversity of sulfated polysaccharides are synthesized by different species of marine sponges

Sulfated polysaccharides were extracted from four species of marine sponges by exhaustive papain digestion. These compounds were purified by anion-exc hange and gel-filtration chromatography. Analysis of the purified polysacch arides revealed a species-specific variation in their chemical composition and also in their molecular masses. In the species Aplysina fulva we found a sulfated glucan with a glycogen-like structure. The other three species c ontained sulfated polysaccharides with variable proportions of galactose, f ucose, arabinose and hexuronic acid and also with different degrees of sulf ation. Although the complex nature of these polysaccharides did not allow c omplete structure determination, we detected the occurrence of 4-sulfated r esidues of fucose and arabinose in the species Dysidea fragilis. The biolog ical role of these sulfated polysaccharides requires further investigation. They may be involved in the species-specific aggregation of sponge cells a nd/or in the structural integrity of sponge, resembling the proteoglycans o f mammalian connective tissues. (C) 2000 Elsevier Science Ltd. All rights r eserved.