Meeting Abstract

P1.106  Monday, Jan. 4  A Time-Course Study of Gene Expression in Gills of the Blue Crab Callinectes sapidus Transferred from Dilute to High-Salinity Seawater. KAUFER, M.J.**; MARKOWSKI, D.E.; LOVETT, D.L.; The College of New Jersey, Ewing lovett@tcnj.edu

Change in gene expression in the gills of crustaceans following transfer from high-salinity to dilute seawater has been examined extensively, whereas the response to transfer from dilute to high-salinity seawater has not. In the blue crab Callinectes sapidus, exposure to dilute seawater initiates a substantial increase in both Na⁺,K⁺-ATPase (ATPase) activity and the relative amount of ATPase α-subunit mRNA. The activity of ATPase remains elevated as long as the crab is in dilute seawater, but the amount of mRNA eventually decreases to near basal levels by the time the crab has acclimated to the dilute seawater. In contrast, when crabs are transferred from dilute to high-salinity seawater, there is a decrease in ATPase activity within 48 h. During this time the amount of α-subunit mRNA drops to near zero, but then begins to increase near the end of the acclimation period. An increase in ATPase activity is not correlated with this increase in mRNA level. These results suggest that chronic exposure to high-salinity seawater may inhibit synthesis of α-subunit mRNA or may activate its degradation . Constitutive degradation of ATPase enzyme may eventually require synthesis of new mRNA in order to maintain basal levels of ATPase enzyme. Supported in part by TCNJ Mentored Undergraduate Summer Experience.