LIPIDS OF LEISHMANIA PROMASTIGOTES

A chromatographic analysis of lipids of cultured promastigotes of Leishmania donovani, L. braziliensis, L. mexicana, L. tropica, L. enrietti, L. hertigi, L. adleri, and L. tarentolae showed that total lipids were 2-15% of dry wt, and neutral and polar lipids were 14-55% and 45-86% of total lipids. Major lipid classes were as follows: sterol ester, triacylglycerol, sterol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylcholine. Predominant fatty acids were 18:2 (n - 6) > 18:3 (n - 3) > 18:1 (n - 9) > 18:0 > 22:6 (n - 3) > 22:5 (n - 6) > 16:0 > 14:0 > 18:4 (n - 3) > 20:3 (n - 3). Some remarkable distributions of fatty acids among the phospholipid fractions were observed, as follows: diphosphatidylglycerol 18-33% 22:6 (n - 3); Phosphatidylinositol 31-68% 18:1 (n - 9); phosphatidylcholine 13-41% 18:3 (n - 3). Alk-1-enyldiacyl glycerols, and alk-1-enylacyl and alkylacyl forms of phosphatidylethanolamine and of phosphatidylinositol were found, and their glyceryl ethers and fatty adehydes analyzed. Notable in the phosphatidylethanolamine of some leishmanias was a cyclopropane fatty acid (4-11%), identified as cis-9,10-methylene octadecanoic acid by chromatographic, and by mass and proton resonance spectrometric analyses. The comparative biochemistry of the cyclopropane fatty acid, characteristics of many prokaryotes, and of α-linolenic acid, characteristic of photosynthetic plants, are commented upon.