THE LOCALIZATION OF HEPARIN-LIKE BLOOD ANTICOAGULANT SUBSTANCES IN THE TISSUES OF SPISULA SOLIDISSIMA

¹ Marine Biological Laboratory, Woods Hole, Mass., and Department of Zoology, University of Pennsylvania, Philadelphia, Pa.

1. A heparin-like blood anticoagulant has been isolated from the surf clam Spisula solidissima.

2. The most potent preparation obtained had an anticoagulant activity of 130 U.S.P. heparin units per milligram and was derived from mantle tissue.

3. Anticoagulant assays made on tryptic digests from various portions of the clam revealed that the mantle, gills and palps had about five times more anticoagulant activity per gram of tissue than the foot and adductor muscles. It was also found that the eggs of Spisula yield a high anticoagulant activity.

4. Toluidine blue staining of sectioned eggs revealed metachromasia in the jelly coat, cortical region and nucleolus.

5. In order to determine the origin of the anticoagulant from the adult clam, the results from anticoagulant assays made on digests of isolated portions of the mantle edge were compared with histologic observations concerning metachromasia. It was concluded that at least two substances with heparin activity are present in the mantle tissue. One of these substances is present in the mucus secretion of the inner mantle fold and apparently also in the mucus secretions of the palps and gills. The mucus secretion of the outer mantle fold was nearly devoid of anticoagulant activity. The other anticoagulant substance seems to be an intercellular material in the connective tissues, possibly analogous to chondroit in sulfate. This substance also seems to be most abundant in the mantle, palps and gills.

6. The possibility that polysaccharide sulfate esters may be important in calcification processes is discussed.