KHODABANDEH, Saber*; GHOLZARI, Alaleh; Tarbiat Modarres University; Tarbiat Modarres University: Immunolocalization of Na+/K+ pump in the branchial cavity of Palaemon elegans (Decapoda, Crustacea) and effects of mercury on Na+,K+-ATPase immunoreactivity

The monoclonal antibody IgG-alpha5 have been widely to identify Na+/K+ pump. Ultrastructure, Na+/K+ pump localization, and effects of mercury on Na+,K+-ATPase immunoreactivity were investigated in the branchial cavity of Palaemon elegans. Each branchial cavity contains 8 pairs of phyllobranchiate gills, 3 epipodites and a branchiostegite which comprises two irregular thick epithelia. Na+,K+-ATPase (Na+/K+ pump) specific labelling was detected only in the axial zone of the epithelial cells of the gills. Two layers of the epipodites epithelium and the branchiostegite inner epithelium showed a very strong Na+,K+-ATPase immunofluorescence and they appear as the main site of osmoregulation. Ultrastructuraly, these epithelium cells present ionocytes characters and possess numerous Na+/K+ pump on baso-lateral membranes. The number of immunofluorescence cells decreased from 91% in controls to 23% in mercury exposed Palaemon. Ultrastructuraly, mercury exposure increases levels of necrosis and apoptosis of ionocytes and disturbs the Na+/K+ pump. These results confirm that osmoregulatory capacity can be used to detect environmental disturbances in the shrimp P. elegans.