The fatty acid composition of purified fractions of cold-pressed peanut oil

Cold-pressed peanut oil was separated into chromatographically homogeneous fractions by column chromatography. The fatty acid composition of the major fractions was determined by gas chromatography. The phosphatides, and especially the cephalins, had a higher palmitate content than did the triglycerides. Palmitate was the dominant fatty acid in the phosphatidyl-serines.     

Specific Iodination Reaction in the Analysis of a Mixture of Alkenyl Acyl- and Diacyl Choline Phosphatides

Specific iodination reaction has been used in separating alkenyl acyl choline phosphatides from the accompanying diacyl choline phosphatides by thin-layer chromatography. The isolated fractions have been analyzed for their fatty acid chains.     

Plasma membrane lipids of bovine adrenal chromaffin cells

The lipid composition of plasma membranes isolated from bovine adrenal chromaffin cells has been determined. Choline and ethanolamine phosphatides were predominant; the level of lyso compounds was very low. The amount of cholesterol and the cholesterol/phospholipid molar ratio was low compared to those of the other subcellular fractions of chromaffin cells. A complex pattern of neutral glycolipids was observed in contrast to that of gangliosides.     

Quantitative gas chromatography in the structural characterization of glyceryl phosphatides

Inclusion of gas chromatography of diglycerides in the various schemes proposed for sub-fractionation of natural glyceryl phosphatides increases the accuracy of identification and quantitation of the individual molecular species. This is due to its efficiency in classifying the molecular weights and proportions of the diglycerides recovered from thin-layer chromatography according to their degree of unsaturation. Determination of the complete structure of glyceryl phosphatides requires standardization of all steps of the analytical system including lipid extractions, enzyme hydrolyses, and thin-layer and gas chromatography. This presentation reviews some of the practical aspects of quantitative gas chromatography of diglycerides and fatty acids as applied in the determination of the molecular species of glyceryl phosphatides. It is shown that a good gas chromatographic technique effectively counteracts weaknesses in other analytical steps. The additional cross-checks provided by the gas chromatography of the diglycerides greatly improve the overall accuracy of the data and frequently permit perfect reconstitution of the overall and positional distribution of fatty acids, which must be the ultimate test of the success of the entire analytical scheme. Presented at the Short Course on Quantitative Gas-Liquid Chromatography conducted by the AOCS at Rice university, Houston, Texas, July 30-Aug. 4, 1967.     

The lipides of green peas

Summary Crude pea lipides were prepared by extracting lyophilized raw peas with chloroform-methanol, 2∶1, and found to comprise 6% of the dry weight of the peas. The composition of the various fractions of pea lipides was studied by measuring the nitrogen, phosphorus, glycerol, fatty acid, and sugar contents, also by means of paper chromatography following acid hydrolysis. The crude lipides were fractionated with acetone, and the acetone-soluble portion was subjected to countercurrent distribution between n-heptane and 95% methanol. The heptane fraction was found to consist nearly entirely of mixed triglycerides; the methanol fraction was a mixture of triglycerides, phosphatides, sugars, and nitrogenous materials. The acetone-insoluble fraction contained 10% of phosphatidyl inositol and nearly equal amounts of alcoholsoluble and alcohol-insoluble phosphatides. This paper is based on work supported by the Gerber Baby Foods Fellowship and was performed in the Department of Chemistry, University of Illinois, Urbana, Ill. Approved by the director of the New York State Agricultural Experiment Station for publication as Journal Paper No. 1070.     

Phospholipid Constitution of Egyptian Vegetable Oils I: Safflower,Groundnut and Chufa Oils

The phosphatidyl components of three Egyptian vegetable oils, namely, safflower, groundnut and chufa were identified using thin-layer chromatography (TLC). The fatty acids of the total phosphatides as well as those of lecithin and cephalin fractions of each sample were determined by gas-liquid chromatography.     

Studies on lipid and fatty acid composition of human hepatoma tissue

Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography. In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals.     

Analyse hoch ungesättigter Fettsäuremethylester

Analysis of Highly Unsaturated Methyl Esters of Fatty Acids The conditions for an optimum separation and identification of fatty acids having 0-6 double bonds were investigated. Thin-layer chromatographic separation of methyl esters of fatty acids on silver nitrate containing plates by a special technique in two different solvent systems enables a fractionation according to the degree of saturation as well as a resolution of highly unsaturated ω3 fatty acids from their ω6 positional isomers. Subsequent gas chromatography of individual fractions permits the examination of homologues with the same degree of saturation but different chain length.     

Molecular species of glycerolipids of ehrlich ascites cells and of their fat granules

Ehrlich ascites cells were grown in mice and were isolated by centrifugation of the ascites fluid. The cells were lysed with distilled water, and the floating fat particles were collected by centrifugation. The particles contained about 90% neutral and 10% polar lipid. The neutral lipid was made up of about 50% triacylglycerol, 30% alkyldiacylglycerol, 3% cholesteryl esters, 3% free cholesterol and 4% free diacylglycerols. The phospholipid fraction was comprised of about 50% phosphatidylcholine, 35% phosphatidylethanolamine, 10% sphingomyelin and small amounts (less than 5% total) of serine and/or inositol phosphatides. The triacylglycerol and alkyldiacylglycerol fractions possessed total carbon number and fatty acid compositions closely similar to these reported in the literature for whole ascites cells and for a cell membrane preparation. Likewise, the fatty acid composition of phospholipids from the granules in general was similar to that reported for Ehrlich ascites cells. On the basis of the polar and neutral lipid ratio, the lipid granules of the ascites cells were calculated to possess lipid core diameters of 30–50 nm, which were 40–70 times smaller than those (up to 2μ) measured for the lipid granules of the intact cells by electron microscopy. The characterization of the lipid composition of the Ehrlich ascites lipid granules was completed by determing the molecular species composition of the diacyl, alkylacyl and alkenylacyl phosphatidylethanolamines and of the diacyl and alkylacyl phosphatidylcholines of the ascites cells. It is concluded that the alkyldiacylglycerols of the Ehrlich ascites cells occur largely in the cytoplasmic lipid granules, which appear to consist of many particles of the size and structure of very low density lipoproteins enclosed in membranous sacs.     

Lipids in sea water

Acidified and filtered sea water samples which were extracted with petroleum ether and ethyl acetate have been shown to contain a variety of lipid compounds in trace amounts. Concentrations of these solvent-soluble substances ranged from 0.5 to 6.0 mg/liter, the lower concentrations being found in offshore waters. The solvent extracts of the sea water were separated into eight lipid classes by column chromatography on silicic acid. The fractions eluted with solvents of increasing polarity were characterized by thin-layer chromatography, infrared and ultraviolet absorption and gas chromatography. These techniques revealed a complex mixture of alkanes, alkenes, fatty acids, steroids, phospholipids and many as yet unidentified components. Twenty to thirty alkanes were present as indicated by gas chromatography. No aromatic hydrocarbons were detected. Chromatography of the methyl esters of the fatty acids indicated the presence of acids with chain lengths varying from 14 to 22 carbons, both saturated and unsaturated. In many samples the unsaturated fatty acids containing 18 to 22 carbons predominated. The lipid components varied somewhat in composition as well as concentration from location to location and with season and depth.     

Lecithin in oil-in-water emulsions

Summary A study was made to investigate the use of purified phosphatide in I.V. emulsions. Lecithin isolated from egg yolk and purified by alumina and silica chromatography was analyzed by chromatographic strip techniques as a one-component material. Highly purified lecithin was found to be an inefficient emulsifier. Moreover emulsions containing highly purified lecithin were heat-sensitive. An emulsion physical stability test was developed to evaluate emulsifier formulations containing purified phosphatides for use with small amounts of emulsions (approximately 50 g.). Using this procedure, a considerable number of substances were tested as additives to enhance the purified lecithin's emulsifying power. None were found to be as effective as natural soybean phosphatide, which was used as a control. From these observations it is indicated that pure phosphatides are inefficient emulsifiers and that those phosphatide preparations possessing good emulsifying characteristics are presumably mixtures or complexes of the phosphatides with other substances. This investigation was supported in part by funds from the Office of the Surgeon General. One of the laboratories of the Southern Utilization Research and Development Division. Agricultural Research Service, United States Department of Agriculture.     

Analysis of triglycerides by consecutive chromatographic techniques. II. Ucuhuba kernel fat

The triglycerides from ucuhuba kernel fat (Virola surinamensis) were analyzed using thinlayer adsorption chromatography (TLC) followed by gas-liquid chromatography (GLC). The triglycerides were first separated into three fractions containing 0, 1, and 2 or more double bonds per molecule on silica gel TLC plates impregnated with AgNO₃. The total triglycerides and each individual TLC fraction were then analyzed by GLC for the molecular weights of their component triglycerides and for their fatty acid composition. Quantitation of the TLC fractions was achieved by GLC analysis of their fatty acids using an added internal standard and confirmed by solving simultaneous equations derived from GLC analysis of their triglycerides and fatty acids. Application of these combined chromatographic techniques separated the ucuhuba kernel fat into 23 triglyceride components. Trimyristin and laurodimyristin comprised over half the total triglycerides, which was expected since the fat contained 20.0 mole % laurie and 71.3% myristic acids. Presented at the AOCS Meeting in Houston, Texas, 1965. Supported in part by grants from the National Institutes of Health (AM-06011) and the Corn Products Institute of Nutrition.     

A comparative study of the phospholipids and fatty acids of some insects

Phospholipids of 27 species of insects representing 6 orders and 20 families were examined by DEAE cellulose column chromatography to determine the choline/ethanolamine phosphoglyceride ratios, and by gas chromatography to determine the constituent fatty acids. The phosphorus in the ethanolamine phosphoglycerides accounted for approximately 50% of the total lipid phosphorus in aphids (Homoptera) and in all but one family of Diptera (flies) examined while the phosphorus in the choline phosphoglycerides accounted for only about 25%. Ethanolamine and choline phosphoglycerides were present in approximately equal proportions in one family of Diptera and in the Coleoptera (beetles) examined. In the other insects examined choline phosphoglycerides predominated, ethanolamine phosphoglycerides comprising only about 25–30% of total lipid phosphorus as they do in most mammalian tissues. Diptera in which ethanolamine phosphoglycerides were the major phosphatides were also characterized by high proportions of fatty acids less than 18 carbons long, particularly palmitoleic acid, in the neutral lipids. Aphids are characterized by a preponderance of 14-carbon fatty acids. The evidence suggests that predominance of ethanolamine phosphoglycerides is associated with a preponderance of shorter chain fatty acids in the neutral lipids. Differences also exist between Diptera and other insects in the fatty acid compositions of different phosphatides, particularly with respect to the distribution of 18-carbon acids. The compositions observed in insects that contained large amounts of the choline phosphoglycerides are similar to those found in vertebrates. Similarities in fatty acid composition of the choline phosphoglycerides in such widely divergent organisms suggest that the fatty acids may play a greater role in phospholipid function than has heretofore been demonstrated. Contribution Number I.P.R.I. 74.     

Lipids ofKlebsiella pneumoniae: The presence of phosphatidyl choline in succinate-grown cells

The carbon and energy source for aerobically grown cultures ofKlebsiella penumoniae profoundly influenced the total lipid content and phosphatide composition. Glucose-grown cells contained 13% lipid, 56% of which was phospholipids. Succinate-grow cells contained 8% lipid, 66% of which was phospholipids. The predominant phosphatides of glucose-grown cells were phosphatidyl ethanolamine, 82%; phosphatidyl glycerol, 4.5%; phosphatidic acid, 5%; cardiolipin, 6.5%; phosphatidyl serine; and trace amounts of unidentified phosphatides. Phosphatides of succinate-grown cells were phosphatidyl ethanolamine, 38%; diphosphatidyl glycerol, 14%; phosphatidyl glycerol, 13%; phosphatidyl choline, 14.5%; phosphatidyl serine, 6%; phosphatidic acid, 4%; and 10% unknown lipids. No trace of phosphatidyl choline was found in glucose-grown cells. Paper 75-11-170 of the Kentucky Agricultural Experiment Station.     

Embryonic vs tumor lipids: II. Changes in phospholipids of developing chick brain,heart, and liver

Brain, heart, and liver tissues were excised from embryos and chicks 10, 13, 16, 19, 22, 27, and 53 days after incubation was initiated and the lipids extracted. The quantitative distribution of the phospholipids and the fatty acid composition of the individual phosphatides were determined for each time period. Each tissue exhibited a distinct phospholipid composition that differed from the composition of egg. Elevated concentrations of particular phosphoglycerides that characterize certain mature tissues were observed at the earliest time period. As development progressed, some phospholipid classes in all tissues showed dramatic change, while others remained relatively constant. Brain showed the most stable composition, while the phosphatides of liver were the most dynamic. Each phospholipid class exhibited a characteristic fatty acid profile that was unique for each tissue. All of the phospholipid classes showed a change in fatty acid composition as development progressed, and, in some tissue, the change was dramatic. The fatty acid composition of brain phosphoglycerides showed the least change, while liver showed the greatest fluctuation. Docosahexaenoic acid and, in most cases, arachidonic acid decreased in the phosphoglycerides with increased development. The decrease in docosahexaenoic acid correlated well with the decreasing mitotic indices of heart and liver cells as development progressed. Comparison of observed abnormal lipid patterns between mature and neoplastic tissue with embryonic tissue lipid profiles suggest that some of the observed abnormalities of neoplasms probably are due to changes in lipid metabolism associated with rapidly proliferating cells, whereas other abnormalities appear to be associated with neoplasia.     

Lipid and fatty acid composition of testes of quaking mice

Testes of quaking mice (sterile mutants) and of controls were analyzed for major lipid classes and fatty acid composition. Of the main lipid classes, only cholesterol esters differed significantly in concentration between the two groups (1.01 for quakers vs 0.69 mg/g wet wt of tissue for controls). The concentration of triglycerides was 4.5–5.0, that of total phosphatides 18–19, and that of free cholesterol 1.9–2.0 mg/g for mutants and controls. The concentrations of phosphatidyl ethanolamine and of sphingomyelin were both lower in quaking than in normal mice, but only the change in the former was statistically significant. Phosphatidyl choline was the major phosphatide (43–45% of total phosphatides) followed by phosphatidyl ethanolamine (24–26%) and sphingomyelin, phosphatidyl serine, and phosphatidyl inositol (all ca. 7% of total phosphatides). Minor differences between the mutants and controls were observed in concentrations of fatty acids of major lipid classes. The mutants, sterile because of faulty spermatid differentiation, had normal quantities of 22∶6 w3 and 22∶5 w6. These data are consistent with the hypothesis that the 22-carbon polyenes are associated with the formation of spermatids, rather than with their final differentiation into spermatozoa.     

Soybean “lecithin” and its fractions as metal-inactivating agents

Summary The addition prior to deodorization of 0.1% of either crude phosphatides, or the alcohol-soluble, or the alcohol-insoluble fraction all improved the oxidative stability and the initial flavor of soybean salad oil. However all three additives caused significant darkening of the oils and the introduction of undesirable storage flavors when added at levels which improved the oxidative stability. High-sugar fractions from the crude phosphatides did not darken the oil nor did they confer improved oxidative or flavor characteristics. Cadmium-precipitated lecithin and inositol-phosphatidic acids containing no amino nitrogen gave lower color to salad oils upon deodorization than did the amino-nitrogen-containing phosphatides. Purified cadmium-precipitated lecithin had little effect upon the oxidative stability when added at levels below 0.02%. A significant improvement results from the addition of 0.05%, and oxidative stability shows further improvement by raising the level to 0.1%; however no increase in stability was obtained by raising of the concentration above this level. At concentrations of 0.01 and 0.05%, cadmium-precipitated lecithin had little effect on the color of the oil. At levels of 0.1 and 0.2%, significant darkening of the oils occurred though much less than with the amino-nitrogen-containing phosphatides. Based on the flavor responses of oils to which these phosphatides were added, it appears that phosphatides constitute the precursors for the melony, bitter, cucumber flavors frequently encountered in aged soybean salad oils. These flavor responses are the same as those obtained from added phosphoric acid. Presented at fall meeting of American Oil Chemists’ Society, Nov. 2–4, 1953, in Chicago, Ill. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Service, U. S. Department of Agriculture.     

Fatty acid composition of rat hearts as influenced by age and dietary fatty acids

Fatty acid composition of neutral and polar lipid fractions from rat hearts was determined in rats of different ages as their diet source changed. Piebald rats were weaned at 21 days and were fed standard lab chow. Lipids from rat hearts, mothers milk and lab chow were purified on a Sephadex G-25 fine column and separated into neutral and polar lipid fractions by silicic acid column chromatography. These lipid fractions were then hydrolyzed and methylated with BF₃ in methanol, prior to gas liquid chromatographic separation on a 1/8 in. × 10 ft aluminum column of 15% EGS on 80–100 mesh acid-washed Chromosorb W. Three major fatty acids in the neutral lipid fraction comprised 72% of total neutral lipid fatty acids from young hearts. At sexual maturity (at least 74 days old) C_18∶1 was the major fatty acid, followed by C_16∶0 and C_18∶0. The same three fatty acids comprised 83% of total polar lipid fatty acids, but C_18∶0 was the major fatty acid, followed by C_16∶0 and C_18∶1. The fatty acid composition of dietary lipids influenced the total neutral lipid fatty acid composition of the rat heart, but had little influence on the fatty acid composition of the polar lipid fraction. Presented in part at the AOCS Meeting, New Orleans, April 1970.     

Lipid composition and endogenous respiration of pig heart mitochondria

Lipid composition and endogenous respiration of pig heart mitochondria were studied in parallel, since the level of endogenous respiration affects the oxidation of added substrates and therefore the regulation of oxidative phosphorylation; mitochondrial lipids can interfere either as substrates or as partner in the energy conservation mechanism. O₂ uptake kinetics were measured in presence of different additives: ATP, ADP, NAD⁺ and hexokinase + glucose. The lipid composition of pig heart mitochondria was determined by chromatographic and spectrophotometric methods. Total lipids were 90% phospholipids; the main phosphatides were cardiolipin, phosphatidyl choline and phosphatidyl ethanolamine; the two latter were rich in plasmalogens. The main nonpolar lipids were triglycerides and free fatty acids. The fatty acid composition of total lipids, phospholipids, free fatty acids and triglycerides was determined by gas liquid chromatography. Mitochondrial lipids were characterized by a high content of unsaturation. Part of this work is included in “Thèse de Doctorat de Spècialitè en Biochimie” de J. Comte, Lyon, June 26, 1970.     

Lipids of cultured hepatoma cells: I. Effect of serum lipid levels on cell and media lipids

Minimal deviation hepatoma cells were cultured as monolayers to confluency in roller flasks containing modified Swim's medium, supplemented with decreasing amounts of serum, lipid-free serum, and lipid-free serum containing added fatty acids. Good cell growth was observed until serum levels fell below 5% of the medium. Media containing lipid-free serum or lipid-free serum plus linoleic or palmitic acids did not support good growth. Lipids were extracted from cells; media, obtained during the first and last half of the incubation period, resolved into neutral and phospholipid fractions; fatty acid composition of each fraction analyzed by gas liquid chromatography; and lipid class distributions compared by thin layer chromatography. The data showed that the media contained more neutral lipids and phospholipids after incubation than initially, indicating that minimal deviation hepatoma cells excreted lipids into the media. The class composition of the excreted lipids resembled that of the serum. A comparison of media, cells, and serum fatty acid compositions indicated that the lipids secreted into the media were of cellular origin. Although some differences were noted, in general, cells grown on the nine different media had the same ca. neutral lipid and phospholipid class and fatty acid compositions. In contrast, dramatic differences were observed in the class and fatty acid compositions of the serums from that of the cells and media. These results indicate that exogenous serum lipids had little influence on cellular class and fatty acid compositions of the minimal deviation hepatoma cells. This neoplasm did not contain detectable levels of glyceryl ether diesters, indicating that this compound is not characteristic of all tumors. Lipid class profiles and fatty acid compositions of cells grown on various media suggest that the minimal deviation hepatoma cells can synthesize most, if not all, neutral lipid and phosphoglyceride classes found in liver. Presented at the AOCS Meeting, New Orleans, April 1973.