title: Phospholipid composition and metabolism of crustacean gills as related to changes in environmental salinities: relationship between Na+-K+-ATPase activity and phospholipids.
abstract: The phospholipid composition and metabolism are studied in crustacean gills. It is reported that branchiae are rich in PC, PE and DPG and abundant in long chain polyunsaturated fatty acids (20:4 omega 6 and 20:5 omega 3 acids). The pathways of phospholipids synthesis appear similar to those described for vertebrates. It is demonstrated that there exist significant differences in the level of phosphatides between the anterior and posterior gills of Eriocheir sinensis. No matter what the salinity, the three more posterior located gills of Chinese crabs are shown to contain much more unsaturated phospholipids (PE and DPG). This is particularly true when animals are acclimated to dilute media. Moreover, lipids of posterior gills appear more fluid than the anterior ones as reported by the values of the degree of fluorescence polarization and the index of unsaturation of fatty acids. It is suggested that these lipid changes may indicate the existence of a functional difference between the various branchiae of euryhaline Eriocheir sinensis with respect to their ability to transport salt. It is shown that the renewal of DPG and PS is increased in posterior gills isolated from freshwater Chinese crabs. It is postulated that the enhanced formation of DPG in posterior gills is an indicator of an increased synthesis of mitochondria having as principal function to produce the necessary energy for the Na+ uptake. An attempt is made to correlate the PS metabolism and the Na+-K+-ATPase activity which is particularly located in the mitochondrial fractions of the three pairs of posterior gills.
mesh_terms: D000818:Animals; D003386:Brachyura / Q000502:physiology*; D005231:Fatty Acids, Unsaturated / Q000502:physiology; D005880:Gills / Q000201:enzymology*; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000502:physiology; D010743:Phospholipids / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014882:Water-Electrolyte Balance
chemical_list: D005231:Fatty Acids, Unsaturated; D008563:Membrane Lipids; D010743:Phospholipids; D000254:Sodium-Potassium-Exchanging ATPase