The origin of phospholipid ethanolamine and choline in a sawfly, Acantholyda nemoralis

Abstract

The origin of phospholipid ethanolamine and choline was investigated in Acantholyda nemoralis by injecting the larvae with 14C formate as a precursor of 3-C of serine. Phospholipids were then extracted and chromatographed on silicic acid and alumina columns. The homogeneity of each of the fractions was checked using thin-layer chromatography, and their nature was proved by means of paper chromatography of the products of the mild alkaline hydrolysis. The predominant phospholipids are stated to be those containing choline (64 per cent) and ethanolamine (23 per cent). The radiocarbon was detected in all phospholipids including the cardiolipin-like acidic phosphatides. The highest specific radioactivity was found in the phosphatidylethanolamine fraction, containing labelled phosphatidylmonomethyl- and phosphatidyldimethylethanolamine. The probable pathways of the biosynthesis of phosphatidylethanolamine and phosphatidylcholine in A. nemoralis are discussed.