Some Phytomonas and Herpetomonas species form unique iso-branched polyunsaturated fatty acids

Four trypanosomatid flagellates of the genera Phytomonas and Herpetomonas have been found to carry out the de novo biosynthesis of a variety of iso-branched, C 18, C 20 and C 22, polyunsaturated fatty acids, with 2–5 methylene-interrupted double bonds, which have not been described heretofore from natural materials; iso-C 18 Δ 6,9, iso-C 18 Δ 9,12, iso-C 18 Δ 6,9,12, iso-C 20 Δ 8,11,14, iso-C 20 Δ 5,8,11,14, iso-C 22 Δ 4,7,10,13,16. Identifications were based upon combinations of chromatographic, chemical degradative, mass spectrometric and proton nuclear magnetic resonance spectrometric techniques. Under appropriate culture conditions, 85% of the total fatty acids of the organisms were branched. The subject trypanosomatids are recommended as model organisms with which to investigate influences of the physical properties of phospholipid fatty acyl groups on eukaryotic cell membrane functions.