Fig. 2. The expression levels of Ostf mRNA in Percoll^TM-gradient-isolated gill pavement cells (PVCs) and chloride cells (CCs). Gill epithelia were dissected and digested; the cell suspension was centrifuged in Percoll^TM gradient solution. The respective gill cell type was isolated, and total RNA was extracted and reverse transcribed for real-time PCR assay. (A) Comparison of Ostf expression levels in isolated freshwater PVCs and CCs. ^*P<0.05 compared with the PVC. (B) Change in Ostf mRNA expression levels in the gill PVCs and CCs isolated from fish at day 0.25, 1, 3 and 7 of seawater acclimation. A significant induction of Ostf mRNA in gill CCs after 0.25 days of seawater acclimation was measured. ^*P<0.05 compared with freshwater CCs. A small but significant increase of Ostf mRNA in isolated gill PVCs after 0.25 days of seawater acclimation was noted. P<0.05 compared with the isolated freshwater PVCs. The results were obtained from four independent experiments.