Ultrastructural localization of metal binding sites in the kidney of the Antarctic scallop Adamussium colbecki

The functional morphology of kidney cells and the intracellular localization of metal storage sites were studied by electron microscopy and X-ray microanalysis in the Antarctic scallop Adamussium colbecki (Smith) collected at Gerlache Inlet, Terra Nova Bay, Antarctic in December 1990. Kidney cells of A. colbecki show the same basic cytoarchitecture of other Pectinidae, but the nephrolithes localized in the main vacuoles show a low degree of mineralization. The sites of heavy metal storage are: (1) the main vacuole of the renal cell, where Fe, Zn and Cu are associated with concretions, (2) the basal membranes and (3) the lysosomes of amoebocytes, in which Ag, Se, Fe and Cu occur in electron-dense particles. Finally a hypothesis for the formation and role of the Ag–Se rich particles is discussed.