Anticoagulant sulfated glycosaminoglycans in the tissues of the primitive chordate Styela plicata (Tunicata)

We performed a biochemical and histochemical study of sulfated glycosaminog lycans in the tissues of the ascidian Styela plicata, A highly sulfated der matan sulfate and a heparin-like polymer, identified by incubation with spe cific lyases, occur at different concentrations in intestine, heart, pharyn x, and cloak. Dermatan sulfate prevails in the pharynx, whereas the heparin -like polymer abounds in the intestine. Staining of tissues sections with t he cationic dye 1,9-dimethylmethylene blue before and after incubation with specific lyases revealed that the dermatan sulfate occurs in the extracell ular matrix, while the heparin-like polymer is located within cytoplasmic g ranules of cells in the lumen of intestine and pharynx. The dermatan sulfat e has a similar disaccharide composition in all tissues studied, whereas th e heparin-like polymer differs in sulfate content. A direct relationship be tween sulfate content of the heparin-like polymer and antithrombin activity was observed. Analysis of the repeating disaccharide units of the heparin- like polymer indicates the presence of relatively high amounts of the disul fated disaccharide namely Delta UA-1-->4-GlcN(SO4)-(6SO(4)), which may sugg est the occurrence in ascidians of regulatory biosynthetic mechanisms diffe rent from those observed for heparin in mammals.