INFLUENCE OF SALINITY ON THE BIOCHEMICAL-COMPOSITION OF THE ROTIFER BRACHIONUS-PLICATILIS (MULLER) - ASPECTS OF ADAPTATION

1. The influence of hypo- and hypersalinity on the content of total proteins, lipids, carbohydrates, glycogen, free amino acids, protein amino acids, lipid class composition and fatty acids of total, polar and neutral lipids in Brachionus plicatilis has been examined. 2. The protein, carbohydrate and glycogen content decreased with a simultaneous increase in the free amino acid content on an increase in salinity from 0.5 to 28 parts per thousand. Salinity exerts the most appreciable effect on the content of such free amino acids as glycine, alanine, proline, arginine and glutamic acids. Alterations in the protein amino acid content were not observed. 3. At salinities of less than 17 parts per thousand and more than 17 parts per thousand, the lipid content decreased. Proportionally this effect was larger at high salinities. 4. Lipid class composition was invariable in the range of salinity from 0.5 to 17 parts per thousand. With a rise of salinity from 17 to 28 parts per thousand the portion of phospholipids increased while that of triacylglycerols, sterol and wax esters decreased. 5. An increase in the proportion of saturated acids and decrease of polyunsaturated acids with increased salinity were characteristic for the fatty acid composition of polar and neutral lipids. This was most perceptible in the range between 0.5 and 4 parts per thousand. 6. The possible mechanisms of biochemical adaptation of the rotifer B. plicatilis are discussed.