The phospholipids of ox spleen with special reference to the fatty acid and fatty aldehyde compositions of the lecithin and kephalin fractions

The fatty acid composition of the major phosphoglycerides of ram and human spermatozoa

The major individual phosphoglycerides of ram spermatozoa have specific fatty acid compositions, whereas human spermatozoan phosphoglycerides contain a similar pattern of fatty acids. The difference in the polyunsaturated:saturated fatty acid ratio of the spermatozoan phosphoglycerides between the two species were associated with the very high polyunsaturated fatty acid content of ram spermatozoan plasmalogens. The major unsaturated fatty acid of ram spermatozoa phospholipids, docosahexaenoic acid, was concentrated in the choline phosphoglycerides, whereas the chief saturates of ram and human spermatozoa, and docosahexaenoic acid in the latter, were largely located in the choline and ethanolamine diacylphosphoglycerides.

Incorporation of isobutyrate and valerate into cellular plasmalogen by Bacteroides succinogenes

Wegner, G. H. (University of Wisconsin, Madison) and E. M. Foster. Incorporation of isobutyrate and valerate into cellular plasmalogen by Bacteroides succinogenes. J. Bacteriol. 85:53-61. 1963.-Bacteroides succinogenes was found to require both a branched-chain volatile fatty acid (e.g., isobutyric) and a straight-chain acid (e.g., valeric) for growth. The organism used the acids as precursors for the synthesis of long-chain fatty acids and fatty aldehydes, which in turn were employed in the synthesis of phospholipid, mainly ethanolamine plasmalogen. Isobutyric acid was incorporated primarily into branched-chain C(14) and C(16) acids (tentatively identified as 12-methyl tridecanoic and 14-methyl pentadecanoic acids, respectively), and into fatty aldehydes. Valeric acid was used mainly for the synthesis of n-C(13) and n-C(15) fatty acids and fatty aldehydes. Apparently the two short-chain fatty acids were built up by the addition of two-carbon units to form the long-chain acids and aldehydes of the plasmalogen.

Metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. II. Biosynthesis of higher branched-chain fatty acids and aldehydes

Allison, M. J. (Dairy Cattle Research Branch, USDA, Beltsville, Md.), M. P. Bryant, I. Katz, and M. Keeney. Metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. II. Biosynthesis of higher branched-chain fatty acids and aldehydes. J. Bacteriol. 83:1084-1093. 1962.-A number of strains of rumen bacteria require branched-chain volatile fatty acids for growth. A strain of Ruminococcus flavefaciens that requires either isovalerate or isobutyrate incorporates radioactive carbon from isovalerate-1-C(14) and isovalerate-3-C(14) into leucine and into the lipid fraction of the cells. Evidence obtained by both paper and gas chromatography indicated that most of the label in the lipid of cells grown in isovalerate-1-C(14) was in a branched-chain 15-carbon fatty acid, with some in a 17-carbon acid; about 7.5% of the C(14) was recovered in a branched-chain 15-carbon aldehyde. The aldehydes were in the phospholipid fraction and were presumably present as plasmalogen.A strain of R. albus was shown to require isobutyrate, 2-methyl-n-butyrate, or 2-ketoisovalerate for growth. This strain did not incorporate appreciable C(14) from isovalerate-1-C(14) or isovalerate-3-C(14). When grown in a medium containing isobutyrate-1-C(14), most of the cellular C(14) was found in the lipid fraction. Analysis of the lipid demonstrated that the label was present mainly as branched-chain 14-carbon and 16-carbon fatty acids, with 11% of the C(14) present in 14- and 16-carbon carbonyl compounds, presumably branched-chain aldehydes.Branched-chain 14-, 15-, and 16-carbon fatty acids are major components of the lipids of these rumen bacteria. The possibility that these acids and aldehydes, which are found in ruminant body and milk lipids, may be of microbial origin is discussed.

THE ISOLATION AND PARTIAL CHARACTERIZATION OF THE GLYCOLIPIDS OF BP8/C3H ASCITES-SARCOMA CELLS

1. The total lipid was extracted from BP8/C3H ascites-sarcoma cells with acetone, light petroleum, pyridine and chloroform-methanol successively. Each extract was treated with mild alkali. The alkali-stable lipids from the pyridine and chloroform-methanol extracts, which included the glycolipids, were fractionated on silicic acid and silica gel G columns. 2. The total yield of glycolipid was about 60 mg./100 g. dry wt. of tumour cells, about 0.4% of the total lipid. Four classes of glycolipid were isolated and characterized as ceramide monohexoside (G1), ceramide dihexoside (G2), ceramide trihexoside (G3) and ceramide hexosaminyltrihexoside (G4). 3. G1, G2, G3 and G4 constituted 55, 21, 9 and 15% of the total glycolipid respectively. 4. G1 was a mixture of ceramide glucoside (70%) and ceramide galactoside. 5. The general structures of the oligosaccharide moieties of G2, G3 and G4 were elucidated by partial acid hydrolysis of the glycolipids with water-soluble polystyrenesulphonic acid. G2 was mostly ceramidelactoside with about 10% of ceramide galactosylgalactoside. G3 and G4 were probably a ceramide digalactosylglucoside and a ceramide N-acetylgalactosaminylgalactosylgalactosylglucoside respectively. 6. The fatty acid compositions of the glycolipids were very similar; lignoceric acid and nervonic acid were the major components and all contained monohydroxy acids in proportions varying from 10 to 25% of the total acids.

Characterization and analysis of the subclasses and molecular species of choline phosphoglycerides from porcine heart by successive chemical hydrolyses and reverse phase high-performance liquid chromatography

Choline phosphoglycerides (CPG) represent the major fraction of heart phospholipids. Since depletion of membrane phospholipids and accumulation of lyso-compounds, particularly lysophosphatidylcholines, have been implicated in arrhythmogenesis, it was of great interest to study the composition of this major phospholipid fraction of the heart at a molecular level in an established animal model. The data presented here describe the first report on the detailed chemical examination of CPG and resolution, characterization and quantitative analysis of the molecular species of this phospholipid fraction from porcine heart by high performance liquid chromatography (HPLC). This fraction constitutes 37.5 +/- 0.7% (n = 21) of the total phospholipids and upon successive mild acid and alkaline hydrolyses revealed the presence of essentially three subclasses: diacyl-, alkenylacyl-, and alkylacyl glycerophosphorylcholines, in a relative abundance of 57.7 +/- 2.2% (n = 8), 37.3 +/- 1.3% (n = 8) and 4.6 +/- 0.2% (n = 8), respectively. The fourth subclass, dialkyl CPG was found only in minute amounts (0.43 +/- 0.05%, n = 8) and the presence of dialkenyl and alkenylalkyl analogues could not be detected. Alternatively, by converting the CPG fraction to benzoate derivatives after phospholipase C digestion, it was possible to isolate and quantitate subclass composition by TLC/spectroscopy or both subclass compositions and molecular species analysis by HPLC directly by a UV detector online with the column. By these techniques, subclass composition was found to be very similar to that obtained by the chemical hydrolysis technique. By HPLC, up to 25 species can be identified and quantitated in each subclass, their identity being confirmed by gas-liquid chromatography, after their isolation from the column. The analyses showed that up to 74% of the diacyl moiety consisted of 16:0-18:2 (34%), 16:0-18:1 (27%), and 18:0-18:2 (13%) species, while the major species of the alkenylacyl moiety were 16:0-18:2 (44%) 16:0-18:1 (13%), 16:0-20:4 (12%) and 18:1-18:2 (9%) making up more than 75% of the total mass of this subclass. The major molecular species of the alkylacyl moiety was 16:0-18:2, constituting up to 47% of this fraction, while others constituted about 10% (16:0-18:1), 9% (18:1-18:2), 8% (16:0-20:4) and 6% (18:0-18:2), making up 80% of the total mass. The ether chain composition of akylacyl CPG whether determined after isolation of this fraction by the chemical hydrolysis technique or by HPLC was indistinguishable.(ABSTRACT TRUNCATED AT 400 WORDS)

Metabolism of fatty acids by bovine spermatozoa

The incorporation of (14)C-labelled myristic, palmitic, stearic, oleic and linoleic acids in vitro into the lipids of bovine spermatozoa was measured at intervals from 2min to 2h. All acids were rapidly incorporated into diglycerides, myristic acid being metabolized to the greatest extent. Whereas the low incorporation of acids into total phospholipids reflected the relative stability of the major phospholipid fractions in sperm, the minor phospholipids, particularly phosphatidylinositol, showed comparatively high metabolic activity. Although, in general, saturated acids were incorporated more actively than unsaturated substrates, stearic acid was poorly incorporated into all lipids except phosphatidylinositol. In regard to fatty acid composition of sperm lipids it was notable that diglycerides contained myristic acid as the major component, and this acid was also a prominent moiety of phosphatidylinositol. Docosahexaenoic acid was the principal fatty acid of the major phospholipid classes. These findings have been discussed in relation to the role of lipids in the metabolism of spermatozoa.

Quantitative determination of alk-1-enyl- and alkyl-glyceryl ethers in neutral lipids and phospholipids

A quantitative method for the simultaneous determination of alk-l-enyl- and alkyl-glyceryl ethers is described. Complete hydrogenolysis of carboxylate and phosphate esters of neutral lipids and phospholipids was achieved with lithium aluminum hydride. The hydrogenolysis products of the glyceryl ether containing lipids, alk-l-enyl- and alkyl-glyceryl ethers and alcohols, were identified by thin-layer chromatography (TLC), gas-liquid chromatography (GLC), and infrared spectroscopy. The alk-l-enyl- and alkyl-glyceryl ethers were quantitated by TLC photodensitometry. The specificity of this method can also be extended when used in conjunction with GLC, ion-complexing TLC, zonal scanning, and autoradiography to study composition, isomeric form, and the biosynthesis of glyceryl ethers in neutral and phospholipids.The percentage of alk-l-enyl- and alkyl-glyceryl ethers in bothtthe neutral lipids and phospholipids of various rat tissues was determined by the described method. Glyceryl ether glycerides represent 0.3-1.2% of the total neutral lipids whereas the glyceryl ether phosphatides of brain, heart, marrow, muscle, and spleen represent 4.5-12.0% of their total phospholipids. Higher concentrations of glyceryl alkyl than of alk-l-enyl ethers were found in the neutral lipids whereas the glyceryl alk-l-enyl ethers were found to predominate in the phospholipids.

Fatty acids in phospholipids isolated from human red cells

Total lipids of packed erythrocytes from healthy men 22 to 25 years old were extracted with chloroform-methanol mixture. Phospholipid classes were separated from neutral lipids and pigments on a silicic acid column. Phosphatidyl inositol (PI) was freed of its contaminants phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) on an aluminum oxide column. Additional silicic acid columns with modified solvent systems were needed for complete separation of other overlapped phospholipid classes. The identification of phospholipids in each eluted fraction was accomplished by TLC, using the appropriate spray tests and reference compounds, and confirmed on each of the isolated phospholipids by IR spectrophotometry.The total content of phospholipids as determined by phosphorus analysis was found to be 2.63 mg/ml of packed cells. These phospholipids were found to have the following composition (in per cent of total phospholipid): PI, 2.3; PE, 13.4; ethanolamine plasmalogen (EP), 14.5; PS, 3.9; lecithin (L), 34.2; choline plasmalogen (CP), 1.4; sphingomyelin (Sph), 28.4 and lysolecithin (LL), 1.7. The fatty acid composition of each phospholipid was determined by GLC. The average number of double bonds per fatty acid in the isolated phospholipids was found to be as follows: PI, 1.5; PE, 1.9; EP, 3.6; PS, 2.1; L, 1.0; CP, 2.0; Sph, 0.2 and LL, 0.5. The positional distribution of fatty acids in both L and PE was ascertained by selective enzymatic hydrolysis with phospholipase A. Saturated fatty acids of L were esterified predominantly in the alpha'-position, whereas in PE only 63.9 mole per cent of the saturated fatty acids were found in this position.

Phospholipids of human serum

Phospholipids extracted from normal human serum were fractionated into lecithin, lysolecithin, sphingomyelin, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, phosphatidyl serine, and phosphatidyl inositol. Identification of each was established by thin-layer chromatography and infrared spectrophotometry. The content of plasmalogen was determined in both lecithin and phosphatidyl ethanolamine fractions. The composition of fatty acids and fatty aldehydes in isolated phospholipids is presented. The degree of unsaturation as reflected in the average content of double bonds per molecule of the fatty acids in phospholipids was: lecithin 1.2, choline plasmalogen 2.1, lysolecithin 0.6, sphingomyelin 0.2, phosphatidyl ethanolamine 2.8, lysophosphatidyl ethanolamine 1.0, phosphatidyl serine 1.0, and phosphatidyl inositol 1.8. Both chlline and ethanolamine plasmalogen aldehydes were predominantly saturated. Molecular weight of each phospholipid was calculated from determined fatty acid and fatty aldehyde compositions; the phosphorus factor for each phospholipid was computed. On a weight percent basis, lecithin, sphingomyelin, and lysolecithin accounted for 95% of the total phospholipids. The ethanolamine-containing phospholipids accounted for 2.5%, and the remainder was divided among phosphatidyl inositol, choline plasmalogen and phosphatidyl serine.