Fatty acids and fatty alcohols of wax esters in the orange roughy: specific textures of minor polyunsaturated and branched-chain components

Total synthesis of 2-methoxy-14-methylpentadecanoic acid and the novel 2-methoxy-14-methylhexadecanoic acid identified in the sponge Agelas dispar

The phospholipid FA composition of the Caribbean sponge Agelas dispar was revisited and 40 different FA were identified. Among these a novel 2-methoxylated FA, namely, the anteiso methyl-branched 2-methoxy-14-methylhexadecanoic acid, was identified together with the recently discovered iso methyl-branched 2-methoxy-14-methylpentadecanoic acid and the normal-chain 2-methoxytetradecanoic acid. The structures of the iso and anteiso methyl-branched 2-methoxylated FA were confirmed by total syntheses, which were accomplished in seven steps and in 45-48% overall yields. Other phospholipid FA identified in A. dispar include the unusual methyl-branched 10,13-dimethyltetradecanoic acid, 3,7,11,15-tetramethylhexadecanoic (phytanic) acid, and the 11-methyloctadecanoic acid. In addition, the delta5,9 FA (5Z,9Z)-15-methyl-5,9-hexadecadienoic acid and (5Z,9Z)-5,9-octadecadienoic acid were characterized. These findings establish alternative FA biosynthetic possibilities for these marine organisms.

The high content of monoene fatty acids in the lipids of some midwater fishes: family Myctophidae

The total lipids of eleven species of Myctophids caught at depths between 20 and 700 m in the northern Pacific Ocean were analyzed using silicic acid column chromatography (lipid classes) and capillary gas chromatography (fatty acid and fatty alcohol composition). The major components in the lipid classes were triacylglycerols or wax esters; triacylglycerols were the dominant acyl neutral lipids (68.1-96.1%) in eight species, and wax esters were found as the dominant lipid (85.5-87.9%) in three species. The major fatty acids and alcohols contained in the wax esters of the three fishes were 18:1n-9, 20:1n-9, 20:1n-11, and 22:1n-11 for fatty acids, and 16:0, 18:1, 20:1 and 22:1 for fatty alcohols. Fatty acids in the triacylglycerols ranging from C14 to C22 were predominantly of even chain length. The major components were 16:0, 16:1n-7, 18:1n-9, 20:1n-11, 22:1n-11, 20:5n-3 (icosapentaenoic acid), and 22:6n-3 (docosahexaenoic acid). In both the triacylglycerols and the wax esters, the major fatty components were monoenoic acids and alcohols. It is suggested from the lipid chemistry of the Myctophids that they may prey on the same organisms as the certain pelagic fishes such as saury and herring, because the large quantities of monoenoic fatty acids are similar to those of saury, herring, and sprats whose lipids originate from their prey organisms such as zooplanktons which are rich in monoenoic wax esters.