bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: V. Photosensitized oxidation
Authors: Frankel E. N. , Neff W. E. , Bessler T. R. 
Published: November 2006

AbstractThe role of singlet oxygen in oxidation was studied by analyzing hydroperoxide isomers in unsaturated fats and esters by gas chromatography‐mass spectrometry (GC‐MS). On oxidation photosensitized with methylene blue at 0 C, methyl oleate produced a 50–50% mixture of 9‐ and 10‐hydroperoxides, linoleate a mixture of 66% conjugated (9+13) and 34% unconjugated (10+12) hydroperoxides, and linolenate a mixture of 75% conjugated (9+12+13+16) and 25% unconjugated (10+15) hydroperoxides. Cottonseed, safflower, and corn oil esters showed, as in soybean esters, the presence of varying amounts of 12‐hydroxy esters derived from the corresponding hydroperoxide at low peroxide values. Since these oils do not contain linolenic acid, a likely source of the 12‐hydroperoxide is linoleic acid by photosensitized oxidation. Several lines of evidence support the conclusion that singlet oxygen may contribute to the unique hydroperoxide composition of vegetable oil esters at low levels of oxidation. In the presence of photosensitizers such as methylene blue and chlorophyll, the unique hydroperoxide composition (high levels of 10‐ and 12‐hydroperoxides) obtained in soybean esters was similar to that produced by oxidation at low peroxide values. In contrast, a normal hydroperoxide composition was produced, as expected from the fatty acid composition of soybean oil esters, when singlet oxygen quenchers such as β‐carotene and α‐tocopherol were used and when the esters were treated with carbon black to remove natural photosensitizers. GC‐MS analyses of the derived unsaturated alcohols provided indirect evidence for 12‐hydroperoxy‐9,13‐diene in soybean esters as expected by photosensitized oxidation of linoleate.
Incorporation of dietarycis andtrans octadecenoate isomers in the lipid classes of various rat tissues
Authors: Wood Randall 
Published: November 2006

AbstractThe percentage distribution of the geometrical and positional isomers in the hexadecenoates and octadecenoates isolated from triglycerides, phosphatidylcholines, and phosphatidylethanolamines of brain, heart, kidney, liver, lung, muscle, spleen, and adipose tissues from rats maintained four weeks on a semipurified diet supplemented with 15% partially hydrogenated safflower fatty acids, has been determined. Except for brain, octadecenoate percentages were increased in each of the lipid classes of all the tissues by the dietary fat. Although the diet did not contain detectable hexadecenoates, the 16∶1 fraction from the lipid classes of all the tissues was composed of 10–70% of thetrans isomers, indicating chain shortening of the dietary octadecenotes. Distribution ofcis andtrans positional isomers in triglyceride hexadecenoates was approximately the same in all tissues. Relatively high percentages of the Δ9, Δ10, and Δ11 isomers were observed, but the Δ8 was the predominatingtrans hexadecenoate isomer, indicating preferential chain shortening of thetrans δ10 octadecenoate.Trans octadecenoates were found in all tissues, but concentrations were dependent on tissue and lipid class. The distribution of thecis andtrans octadecenoate isomers was similar in all the tissue triglycerides, with the distribution of thetrans isomers resembling the diet. In contrast, the percentage distribution of thetrans octadecenoates in the phospholipid classes differed dramatically from the diet, and the distribution was dependent on both the tissue and lipid class. The Δ12, Δ13, and Δ14trans octadiet, suggesting an accumulation of these isomers. Although thecis Δ10 octadecenoate was a significant dietary component, this isomer was not incorporated significantly into any lipid class of any tissue. The metabolic fate of this isomer remains unknown.
Analysis of the conjugated trienoic acid containing oil fromFevillea trilobata by13C nuclear magnetic resonance spectroscopy
Authors: Tulloch A. P. , Bergter L. 
Published: November 2006

AbstractOil ofFevillea trilobata has the composition palmitic acid 31%, stearic acid 12%, oleic acid 11%, linoleic acid 7%,cis,trans,cis 9,11,13‐octadecatrienoic acid 30% andcis,trans,trans‐9,11,13‐octadecatrienoic acid 9%. The oil was analyzed and components identified by13C NMR spectroscopy; the composition was also confirmed by conventional methods. Assignment of13C NMR signals of conjugated trienoic acids is discussed and it is shown that mixtures of isomeric conjugated acids can be analyzed by this method.
Effects of membrane fatty acid composition on sodium‐independent phenylalanine transport in Ehrlich cells
Authors: Im Wha Bin , Deutchler Jon T. , Spector Arthur A. 
Published: November 2006

AbstractWe have examined Na+‐independent phenylalanine transport in Ehrlich cells having different degrees of membrane fatty acid saturation. These differences were produced by growing the cells in mice fed a fat‐free chow supplemented with either sunflower seed oil or coconut oil. Plasma membranes isolated from the cells grown on sunflower oil were enriched with polyenoic fatty acid, especially 18∶2, whereas those isolated from the cells grown on coconut oil were enriched in monoenoic fatty acids, primarily 16∶1 and 18∶1. Arrhenius plots of phenylalanine uptake showed two transitions. The temperatures of these transitions were different in the two cell preparations; 17 C and 24 C for the cells enriched in polyenoic fatty acids, 19 C and 28 C for those enriched in monoenoic fatty acids. Therefore, this transport system is sensitive to changes in the fatty acid composition of the lipid phase in which it operates. The activation energies, however, were the same in both cell preparations; 14, 8 and 4 kcal/mol. There also was no significant effect of the lipid modifications on either the K′m or V′max of this transport process. The K′m for phenylalanine uptake from a choline medium remained constant as the temperature was raised from 17 C to 37 C, whereas the V′max showed about a two‐fold increase in both cell types. Phenylalanine exodus from the cells into an amino acid‐free suspending medium, analyzed using first‐order kinetics, also was not influenced by these membrane fatty acid modifications. The changes in the transition temperatures probably reflect differences in the degree of fatty acid unsaturation of lipids that surround and interact with the phenylalanine carrier. Such differences, however, do not appreciably influence the catalytic activity of this transport system.
Response of free and esterified plasma cholesterol levels in the mongolian gerbil to the fatty acid composition of dietary lipid
Authors: Mercer Nina J. H. , Holub Bruce J. 
Published: November 2006

AbstractThe present study was undertaken to investigate the potential suitability of the Mongolian gerbil as a useful animal model to study the effects of dietary fats on plasma cholesterol levels. Semipurified diets containing either 20% lard, 20% safflower oil, or 19.5% beef tallow +0.5% safflower oil were equalized to contain 0.01% cholesterol and 0.05% plant sterol and were fed for a four week experimental period. The proportions of total calories contributed by fat, protein and carbohydrate (starch/sucrose ratio of 2∶1) were 40, 14 and 46%, respectively, so as to approach the distribution of calories within the average North American diet. Free, esterified, and total plasma cholesterol levels of male gerbils were determined weekly by gas liquid chromatography after drawing blood via a serial sampling technique. After 1, 2, 3, and 4 weeks of feeding the experimental diets, total cholesterol levels were lowest in the safflower oil fed animals; the corresponding values were 19–64% greater in gerbils fed lard and 68–91% greater in those consuming the beef tallow diet. Cholesterol in the free form generally responded more dramatically to the type of dietary lipid than did cholesterol in the ester form. Irrespective of the type of dietary lipid or the length of the feeding trial, 18–23% of the total plasma cholesterol was in the free form and 77–82% was present as the ester. In view of the similarity to the human of the relative proportions of free versus esterified cholesterol, the type of cholesteryl esters, and their response to dietary manipulation, the gerbil appears to be a useful animal model for studying the regulatory effect of dietary lipid on plasma cholesterol levels.
Lipid binding properties of a factor necessary for linoleic acid desaturation
Authors: Leikin Alicia I. , Nervi Anibal M. , Brenner Rodolfo R. 
Published: November 2006

AbstractSuspension and centrifugation of crude microsomes of rat liver in low ionic strength solution separated a soluble protein fraction that is necessary for the full activity of the linoleic acid desaturase. The fraction partially purified through Sephadex G‐150 still retains lipids which are mainly constituted by phosphatidylcholine. Linoleic acid predominates in the fatty acid composition. By NaCl gradient centrifugation and electrophoresis in gelatinized cellulose acetate, the factor behaves like a lipoprotein. The factor binds linoleic acid and linolyl‐CoA that are desaturated to γ‐linolenic acid when incubated with washed microsomes. Albumin does not replace the factor.
Kidney lipids: Changes caused by dietary 9‐Trans, 12‐Trans‐octadecadienoate
Authors: Kinsella J. E. , Yu P. H. , Mai J. B. 
Published: November 2006

AbstractTrans, trans‐linoleate at 50 and 100% of dietary fat decreased kidney size and altered its composition.Trans, trans‐linoleate as the sole source of dietary fat imparied growth and caused more severe symptoms of essential fatty acid deficiency than was observed with hydrogenated coconut oil (HCO). The concentration of renal cholesterol, phospholipids (PL), triglycerides (TG) and cholesteryl esters (CE) were also decreased. Linoleic (18∶2), homo‐γ‐linolenic acid (20∶3n6) and arachidonic acid (20∶4n6) were significantly depressed in lipid classes, especially in PL and CE, by dietarytrans, trans‐linoleate. The increase in eicosatrienoate (20∶3n9), especially in PL and CE of kidneys of rats fed HCO (essential fatty acid deficient), was slight in rats fed 100%trans, trans‐linoleate, indicating that thetrans, trans acid probably inhibited acyl elongation and desaturation.
Autoxidation of fatty acid monolayers adsorbed on silica gel: III. Effects of saturated fatty acids and cholesterol
Authors: Wu Guey‐Shuang , Stein Robert A. , Mead James F. 
Published: November 2006

AbstractAutoxidation of fatty acid monolayers on silica consisting of multiple components to simulate biomembranes has been studied by the rate of fatty acid disappearance and the products formed. When palmitic acid was incorporated into linoleic acid monolayers, the decrease in rate was proportional to the amounts of plamitic acid present. The protective effect of the saturated fatty acid diminished rapidly as the chain length of the saturated fatty acid decreased below C12. With acids of medium chain length, C12 was more effective than C16. In pure linoleic acid monolayers, when the surface coverage was reduced to only 5% of the available adsorption sites, and in the case of palmitic acid‐linoleic acid monolayers, the rate dropped drastically and the major identified product formed was hydroxyepoxyoctadecenoic acid. On the contrary, the major product formed in the case of saturated monolayers of pure linoleic acid was a mixture of unsubstituted epoxy acids. The inclusion of cholesterol in linoleic acid monolayers increased the rate of disappearance of linoleic acid slightly, whereas cholesteryl acetate decreased the rate. The protective effect exerted by cholesteryl acetate appeared to be similar to that of palmitic acid.
Isolation of sterol mutants inChlamydomonas reinhardi: Chromatographic analyses
Authors: Bard M. , Wilson K. J. , Thompson R. M. 
Published: November 2006

AbstractSeveral sterol mutants ofChlamydomonas reinhardi were isolated by selecting for single colonies resistant to the polyene antibiotic, nystatin. The sterol profiles of three isolates—KD7, KD16, and KD21—as well as a wild type strain (137C) were determined by gas liquid chromatography and mass spectrometry. The wild type strain contained ergosterol (C28‐5,7,22‐triene) as the predominant sterol, with smaller amounts of a C28‐5,7‐diene, a C28‐7‐ene, and C‐24 ethyl analogs of these three sterols. The three mutants had altered sterol composition, but none required exogenous sterol for growth. KD7 contained a C28‐5,7,22,25‐tetraene, a C28‐5,7,25‐triene, a C28‐7,25‐diene, and three C‐24 ethyl analogs. The lesion in KD7 is apparently an inability to reduce the C‐25 double bond required for the biosynthesis of ergosterol and an ethyl analog. The predominant sterols accumulated by KD16 and KD21 were a C28‐5,7‐diene, a C28‐7‐ene, and C‐24 ethyl versions of these two sterols, suggesting that these strains are 22(23)‐desaturase mutants.
Δ15, 18‐tetracosadienoic acid content of sphingolipids from platel and erythrocytes of animals fed diets high in saturated or polyunsaturated fats
Authors: Pitas R. E. , Nelson G. J. , Jaffe R. M. , Mahley R. W. 
Published: November 2006

AbstractThe effect of diets high (15%) in saturated (beef tallow) or polyunsaturated (corn or cottonseed oil) fatty acids on the fatty acid composition of sphingomyelin from canine erythrocytes and platelets and sphingomyelin and neutral glycosphingolipids of swine erythrocytes was determined. Sphingolipids of platelets and erythrocytes from animals fed high levels of corn or cottonseed oil exhibited a dramatic alteration in their fatty acid composition, most notable of which was a 50% reduction in nervonic acid (24∶1ω9) as compared to levels observed in control or tallow fed animals. This decrease was compensated for by a quantitatively similar increase in a C24 dienoic acid. The long chain dienoic acid was isolated by silver nitrate thin layer chromatography and determined by analysis of its oxidation products to be Δ15, 18‐tetracosadienoic acid (24∶2ω6). When the animals were fed the diets high in polyunsaturates, the 24∶2ω6 represented 13, 20, and 9% of the sphingomyelin fatty acids from canine erythrocytes, platelets, and swine erythrocytes, respectively, and 5% of the neutral glycosphingolipid fatty acids of swine erythrocytes. In contrast, the 24∶2ω6 represented less than 4% of the total cellular sphingolipid fatty acids in animals fed the control or high beef tallow diets. The 24∶1ω9 in the sphingolipids of the animals fed the polyunsaturated diet was roughly equal to that of 24∶2ω6, whereas in the sphingolipids of animals fed the control or saturated fat (beef tallow) diet, the 24∶1ω9 was twice these values. Since sphingomyelin is a membrane component, the increase in unsaturation (24∶2ω6) in its fatty acid moiety induced by dietary polyunsaturates may affect membrane fluidity and may alter membrane properties.
Effects of synthetic and natural lysophosphatidic acids on the arterial blood pressure of different animal species
Authors: Tokumura Akira , Fukuzawa Kenji , Tsukatani Hiroaki 
Published: November 2006

AbstractIntravenous injection of lysophosphatidic acid was found to cause hypertension in rats and guinea pigs, but hypotension in cats and rabbits. The potencies of the pressor and depressor effects of synthetic lysophosphatidic acids in rats and cats depended on their chain length and the degree of unsaturation of their fatty acyl moieties.
Liver and thymus lipid composition in AKR mice with and without lymphomas
Authors: Kitada Shinichi , Mwasi Lawrence , Mead James F. , Hays Esther F. 
Published: November 2006

AbstractLipid composition of liver and thymus in controls, early stage lymphoma, and advanced stage lymphoma‐bearing AKR mice was studied. There was a significant decrease in the liver total lipid content in mice with advanced lymphoma, whereas in the early stages, no quantitative change was seen. In livers of mice with advanced stage lymphoma, there was a significant decrease in the nonpolar fraction. The decrease was in triglyceride, whereas the cholesterol fractions were relatively increased though highly variable. There was an increase in the polar lipid/nonpolar lipid ratio in the advanced lymphoma livers and a very large increase in the polar lipid/triglyceride ratio, indicating that the decrease in total lipid in these livers was largely in the triglyceride fraction. Similar changes were seen in the thymus, in which the lipid composition reflected the transformation from normal to malignant cells.
Identification of vasopressor phospholipid in crude soybean lecithin
Authors: Tokumura Akira , Fukuzawa Kenji , Akamatsu Yasue , Yamada Sadaji , Suzuki Tetsuya , Tsukatani Hiroaki 
Published: November 2006

AbstractThe vasopressor phospholipid in crude soybean lecithin was isolated by column chromatography on Sephadex LH‐20. It represented 0.1% of crude soybean lecithin. The isolated phospholipid was identified to be lysophosphatidic acid by gas chromatography‐mass spectrometry analysis of TMS‐deacylated product and acetolysis product. Nuclear magnetic resonance analysis favored the 1‐monoacyl isomer over the 2‐isomer. By enzymic determination with L‐3‐glycerophosphate dehydrogenase, the isolated phospholipid was identified as 1‐monoacyl‐L‐3‐glycerophosphate. Gas chromatographic examination revealed that it was composed of a large percentage of unsaturated fatty acids, especially linoleic acid. The activity of isolated lysophosphatidic acid was slightly less than that of synthetic 1‐linoleoyl‐L‐3‐glycerophosphate.
Generation of phospholipid artefacts during extraction of developing soybean seeds with methanolic solvents
Authors: Roughan P. G. , Slack C. R. , Holland R. 
Published: November 2006

AbstractThe major phospholipids of soybean cotyledons during development were phosphatidylcholine (45–55%), phosphatidylethanolamine (24–28%), and phosphatidylinositol (15–18%) when the tissue was steam‐killed prior to extraction of the lipids. The only other phospholipids of any significance (4–6%) was identified as phosphatidylglycerol. Phosphatidic acid was a minor constituent (<1%), and neither N‐acyl phosphatidylethanolamine norbis‐phosphatidic acid were detected in appreciable (>0.1% of the total lipid phosphorus) quantities. When fresh cotyledons were rapidly homogenized in mixtures of chloroform and methanol or in methanol alone, phosphatidylmethanol was formed in variable amounts (0–20% of the total phospholipid), and when cotyledons were soaked in methanol prior to homogenizing, phosphatidylmethanol became the major phospholipid, accounting for up to 75% of the total lipid phosphorus. Phosphatidylmethanol was formed by the phospholipase D‐catalyzed transphosphatidylation of phosphatidylcholine and phosphatidylethanolamine during extraction.
13C Nuclear magnetic resonance spectroscopy of cyanolipids and cyanolipid‐containing seed oils
Authors: Mikolajczak K. L. , Weisleder D. 
Published: November 2006

Abstract13C nuclear magnetic resonance (NMR) signals of all carbon atoms of the hydroxynitrile moieties on which cyanolipids are based have been assigned. The four known types of cyanolipids can be conveniently distinguished and identified by13C‐NMR whether they are in pure form or in unfractionated seed oils from which they are derived.
The effect of dietary fats on the plasma lipid composition of sheep
Authors: Noble R. C. , Vernon R. G. , Christie W. W. , Moore J. H. , Evans A. J. 
Published: November 2006

AbstractThis study reports on the plasma lipid compositions of sheep fed either a control diet (C), a control diet supplemented with tallow (A) or polyunsaturated fatty acid (B) that had been protected against hydrolysis and hydrogenation in the rumen, or a control diet supplemented with maize oil (D). Diet B considerably increased the 18∶2 content of all the major plasma lipid fractions. Although the feeding of diet D also resulted in an increase in the 18∶2 contents within the cholesteryl ester, unesterified fatty acid, and phospholipid fractions the increases were considerably less than those observed with diet B; the levels of 18∶2 within the triglyceride fraction remained similar to that for the sheep which received the control diet. The effect of feeding diet A was confined solely to the triglyceride fraction where the concentrations of 16∶0 and 18∶1 were increased. The lipoproteins of the plasma were separated into very low density lipoproteins (d<1.006), low density lipoproteins (1.006<d<1.063), and high density lipoproteins (1.063<d<1.21), and the distribution of the major lipids between these lipoprotein fractions was investigated. Diet B increased considerably the proportion of triglyceride found in association with the very low density fraction and the concentrations of 18∶2 within all the lipoprotein fractions; these increases in the concentrations of 18∶2 were not confined to any particular lipid fraction of the lipoproteins. In contrast, the increases in the concentrations of 18∶2 produced as a result of feeding diet D were confined to the low and high density lipoproteins. The effect of feeding diet A was confined to fatty acid changes within the triglycerides of the low and very low density lipoproteins.
Sterol mutants ofSaccharomyces cerevisiae: Chromatographic analyses
Authors: Bard M. , Woods R. A. , Barton D. H. R. , Corrie J. E. T. , Widdowson D. A. 
Published: November 2006

AbstractThe sterols accumulated by ergosterol deficient mutants of the geneserg6, erg2, erg3, anderg5 (formerlypo11, po12, po13, andpo15) have been analyzed by gas liquid chromatography. Together with pure sterols obtained from the mutants, they were characterized on SE‐30, OV‐17, and OV‐225. The effects of molecular structure on the retention characteristics of a range of C28 ergostane sterols have been studied. The double mutants obtained by crossing the single mutants were also analyzed and their sterols identified where possible. The effects of theerg mutations on the control of sterol biosynthesis in yeast are discussed.
Metabolism of arachidonate and stearate injected simultaneously into the mouse brain
Authors: Sun Grace Y. 
Published: November 2006

AbstractThe metabolism of a polyunsaturated and a saturated fatty acid in brain membrane phosphoglycerides was examined by injecting simultaneously a mixture of14C‐arachidonate and3H‐stearate into the mouse brain and isolating the microsomal and synaptosomal fractions at 1–40 min after injections. Both types of labeled fatty acids were utilized more readily in the microsomal than the synaptosomal fractions in brain. However, labeled arachidonate was incorporated more rapidly into membrane phosphoglycerides than was stearate. In both subcellular fractions, the relative specific radioactivity (3H and14C) of diacyl‐glycerophosphorylinositol (diacyl‐GPI) was higher than other types of phosphoglycerides such as diacyl‐glycerophosphorylcholine (diacyl‐GPC) and diacyl‐glycerophosphorylethanolamine (diacyl‐GPE). Furthermore, the apparent rates of incorporation of radioactivity into diacyl‐GPI was more rapid for the14C‐arachidonate than for the3H‐stearate. Results of the experiment have demonstrated obvious differences in metabolism between stearate and arachidonate in brain. The more rapid transfer of arachidonate to diacyl‐GPI is probably due to the presence of an acyl transferase system specially active for the transfer of arachidonyl groups to diacyl‐GPI.