ISOLATION AND CHARACTERIZATION OF AQUAPORIN 1 (AQP1), SODIUM/POTASSIUM-TRANSPORTING ATPASE SUBUNIT ALPHA-1 (NA/K-ATPASE ?1), HEAT SHOCK PROTEIN 90 (HSP90), HEAT SHOCK COGNATE 71 (HSC71), OSMOTIC STRESS TRANSCRIPTION FACTOR 1 (OSTF1) AND TRANSCRIPTION FACTOR II B (TFIIB) GENES FROM A EURYHALINE FISH Etroplus suratensis