COMPARATIVE INVESTIGATION OF LIPID AND FATTY-ACID COMPOSITION OF FISHGILLS AND MAMMALIAN LUNGS - A MODEL OF THE MEMBRANE LIPID COMPONENT AREAS

The lipid and fatty acid composition of gills and lungs were studied i n 18 fish species and seven mammalian species. Different relationships among individual phospholipids and different molar ratios between pho spholipids and cholesterol (2:1 in fish and 3:1 in mammals) were found . Conformational analysis of the main phospholipid and cholesterol mol ecules was carried out using a molecular mechanics method. The model o f ''one unit fragment of the membrane lipid component'' accommodates 1 9 lipid molecules in fish and 42 in mammals. The areas of the molecule projections of the main phospholipids do not differ from each other b y more than 2-3%. It may be suggested that the closely packed lipids i n membranes of the aerohaematic barrier protect the organism of mammal s from the high oxygen content in the environment.