Role of membrane lipid in osmoregulatory processes during salinity adaptation: a study with chloride cell of mud crab,Scylla serrata

A significant variation in membrane fluidity, lipid composition, fatty acids profile and intra–extracellular ion concentrations of chloride cells was observed in the estuarine mud crab, Scylla serrata, when they were acclimated to 1 and 35 psu. About 60% decrease in Km and Vmax of Na+/K+-ATPase, Mg2+ ATPase and Ca2+ ATPase enzymes and 85% increase in the same was observed when the crabs were acclimated to 1 and 35 psu saline water, respectively. The changed membrane lipid bilayer composition and fluidity of the plasma membrane of chloride cell help in modulating activity of Na+/K+-ATPase and thus regulate the ionic composition of the cell during salinity adaptation.