Fig. 3. TEM showing the chloride cell ultrastructure from the filamental epithelium of tilapia exposed to 35 g l^–1 salinity for 14 days. (A) Interlamellar epithelium. AC, accessory cell; CC, mature chloride cell; IC, immature chloride cell; A, apical pit. (B) Multicellular complex formed by mature and accessory chloride cells; arrowhead indicates short apical tight junctions between CC and AC. Arrows indicate long tight junctions between CC and PC. A, apical pit; D, desmosome. (C) Perinuclear cytoplasm of a mature chloride cell. M, mitochondria; TR, tubular reticulum. (D) Apoptotic cell with nuclear and cytoplasm condensation and distention of the tubular reticulum. Scale bars: 1 µm.