THE PERICARDIAL GLANDS OF THE ZEBRA MUSSEL - ULTRASTRUCTURE AND IMPLICATION IN LEAD DETOXICATION PROCESS

Ultrastructural and microanalytical investigations of the pericardial gland of the freshwater mussel, Dreissena polymorpha have been perform ed to investigate the possible functional role of this organ in the de toxication process of lead. The cell-type of this organ exhibits the f eature characteristics of podocytes, ie the typical pedicel-basal lami na complex and the well developed lysosomal-vacuolar system. X-ray mic roanalysis demonstrated that large electron-dense granules referred to as lysosomes are the main target organelles in these cells to accumul ate and sequestrate lead where the metal was associated with phosphoru s and sulphur. Consequently, the pericardial gland plays an important role in the detoxication process and allows the organism to tolerate h igh lead concentration without suffering severe cell injury.