DE-NOVO BIOSYNTHESIS OF LINOLEIC-ACID IN 2 NON-INSECT INVERTEBRATES -THE LAND SLUG AND THE GARDEN SNAIL

The de novo biosynthesis of linoleic acid [18:2(n-6)], a fatty acid co nsidered to be essential for most animals, was demonstrated in the lan d snail, Bulimulis alternatus mariae, and the garden slug, Arion circu mscriptus. Radiolabeled acetate injected into the animals was incorpor ated into both 18:2 and 20:2, as demonstrated by radio-high performanc e liquid chromatography (radio-HPLC) and radio-gas chromatography (rad io-GC). GC-mass spectrometry (GC-MS) of the methoxy derivatives of the 18:2 and 20:2 isolated from the snail showed that major isomers had t he double bonds in the n-6,9 positions. Radio-gas-liquid chromatograph y (radio-GLC) of the ozonolysis products from the labeled dienoic fatt y acid methyl esters showed that both ends of the molecules were label ed, confirming de novo synthesis. The production of linoleic acid by t hese animals suggests the capability to produce linoleic acid may be w idespread in invertebrates.