Fig. 3. Differential interference contrast (DIC) and fluorescence images of dispersed gill cells from freshwater rainbow trout (A–C) and seawater-adapted (30) trout (D–F). Cells were obtained from the mitochondria-rich (MR) 1.05–1.09 g ml^–1 Percoll layer and stained with Mitotracker Green-FM (100 nmol l^–1, 20 min; B,E) or labelled with PNA Alexa fluor 594 (40 µg ml^–1; C,F) for identification of MR and PNA⁺ cell types, respectively. All pictures in A–C and D–F are of the same field of view. Scale bar, 10 µm.