Mass spectrometry of fatty acid pyrrolidides

Effect of clomiphene on the content of sterols and fatty acids in Saccharomyces cerevisiae

During cultivation of Saccharomyces cerevisiae clomiphene regulates both quantitative and qualitative production of sterols and fatty acids as identified by gas chromatography and mass spectrometry. The content of sterols decreases to 75%, the production of fatty acids is comparable with that in the control. The occurrence of sterols increases; sterols with methyl group in position 4, without double bond in position 22 and with double bond in position 24(25) or 24(28) predominate. Among fatty acids shorter saturated and monoene acids are primarily produced, 2-hydroxy acids practically disappeared.

Phospholipid studies of marine organisms: new branched fatty acids from Strongylophora durissima

The phospholipids of the sponge Strongylophora durissima were analyzed. The major phospholipids present were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). The major fatty acid components of the phospholipids consisted of short chain (C14-C19) and very long chain (C25 -C30) "Demospongic" acids. Three novel branched delta 5 monounsaturated acids, Z-19-methyl-5-pentacosenoic, Z-19-methyl-5-hexacosenoic and Z-19-methyl-5-heptacosenoic acids were encountered in the sponge. The 3-saturated counterparts of these compounds, 19-methylpentacosanoic, 19-methylhexacosanoic and 19-methylheptacosanoic acids, as well as 19-methyltetracosanoic and 20-methyloctacosanoic acids also are hitherto undescribed acids present in the sponge. Trace amounts of 2 very long chain acids also were detected and their structures tentatively assigned as 19,21-dimethylheptacosanoic and 20,22-dimethyloctacosanoic acids. The distribution of these fatty acids according to phospholipid head groups also was described.

Biosynthesis of the novel fatty acid, 17-methyl-cis-9,10-methyleneoctadecanoic acid, by the parasitic protozoan, Herpetomonas megaseliae

Herpetomonas megaseliae, a flagellate protozoan parasite of the gut of a dipteran, Megaselia scalaris, is shown by chromatographic, spectrometric and radiotracer methods to synthesize de novo an iso-branched chain cyclopropane fatty acid, 17-methyl-cis-9,10-methyleneoctadecanoic acid.

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, C18, C20 and C22, polyunsaturated fatty acids, with 2-5 methylene-interrupted double bonds, which have not been described heretofore from natural materials; iso-C18 delta 6,9, iso-C18 delta 9,12, iso-C20 delta 8,11,14, iso-C 20 delta 5,8,11,14, iso-C22 delta 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.

The cyclopropane fatty acid of trypanosomatids

Cis-9,10-Methyleneoctadecanoic acid, one of a group of cyclopropane fatty acids commonly found in bacteria but not in eukaryotic cells, has been identified in the phosphatidylethanolamines of 27 isolates representing 5 genera of trypanosomatid flagellates (Crithidia, Leptomonas, Herpetomonas, Phytomonas, Leishmania). Its presence did not appear to be associated with endosymbiotic or other microbiol associates. It was absent from 12 isolates of the genera Blastocrithidia, Endotrypanum and Trypanosoma.

Remote group derivatives: limitations on the effectiveness of pyrrolidide derivatives of oxygen-containing fatty acids

The pyrrolidides of a number of fatty acids containing oxygen functions (ether linkage, epoxide ring and hydroxyl group) have been prepared and their mass spectra recorded. Detailed analyses of these, supported by accurate mass measurement, indicate that the presence of the oxygen atom has a profound effect on the normal, sequential, mode of pyrrolidide fragmentation. Cleavage adjacent to the oxygen is enhanced, this being most marked in the spectra of those compounds containing an ether linkage. However, further fragmentation of the carbon chain distal to the pyrrolidide group is minimal and prevents any structural information being obtained. These findings indicate that the usefulness of the pyrrolidide derivative for structural elucidation purposes is severely limited in some cases when an oxygen atom is present in the chain. However, for both the epoxy- and hydroxy-fatty acids, complementary derivatization methods are available.