COMPOSITION OF ACYL-CONTAINING LIPIDS IN MUCOR LUSITANICUS CELL-FRACTIONS UNDER DIFFERENT NITROGEN NUTRITION REGIMES

The fatty acid and fractional composition of lipids of the total membr anes, microsomes,and lipid granules of Mucor lusitanicus was studied a fter cultivation with different methods of addition of the nitrogen so urce. In all cell structures, changes occurred mainly in the content o f glycerolipids (TAG, DAG, and MAG) and free fatty acids. The levels o f free and esterified sterols and phospholipids were more stable. The lipid fatty acid composition of individual cell fractions was differen t and changed ambiguously. In step-by-step addition of the nitrogen so urce, the gamma-linolenic acid content in phospholipids of microsomes and lipid granules increased by 164 and 43%, respectively, and reduced by 40% in membrane phospholipids. Phospholipids of lipid granules had the highest gamma-linolenate content, up to 41.7% of the total amount of fatty acids. TAGs of membrane structures contained more unsaturate d fatty acids, including gamma-linolenic acid, than did TAGs of micros omes and lipid grannies and were more prone to changes.