BIOCHEMICAL-CONSTITUENTS OF THE BLOOD-PLASMA AND PERICARDIAL FLUID OFSEVERAL MARINE BIVALVE MOLLUSKS - IMPLICATIONS FOR ULTRAFILTRATION

Protein and N-acetylamino sugar concentrations are significantly lower in Mercenaria mercenaria pericardial fluid than in blood plasma, alth ough concentrations of Na+, K+, lipid, glucose and carbohydrate are si milar in each compartment. Of the >35 protein subunits identified in p lasma by 7.5% SDS-PAGE, up to 24 are found in pericardial fluid, yet o nly six to 10 are appreciably stained. Three pericardial fluid bands ( 28, 30 and 53 kDa) are absent from plasma. Densitometric measurements imply that the effective threshold for ultrafiltration is above 51 and below 83 kDa. Comparable qualitative SDS-PAGE results were obtained f or Crassedoma giganteum, Patinopecten caurinus, and Mytilus california nus.