bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilization of docosahexaenoic acid from intravenous egg yolk phospholipid
Authors: Morris Scott , Simmer Karen , Gibson Robert 
Published: November 2006

AbstractDocosahexaenoic acid (DHA, 22∶6n−3) is provided directly to human premature infants during parenteral nutrition from the egg yolk fraction of an intravenous fat emulsion. This study aimed to determine whether the high egg yolk phospholipid content of Intralipid 10% (IL 10%, Pharmacia, Uppsala, Sweden) relative to the standard emulsion Intralipid 20% (IL 20%, Pharmacia) could be a strategy to increase the delivery of DHA to the developing brain. Male, Large White piglets were randomly selected from sows 3 d after birth. Piglets were assigned to receive a 9‐d continuous intravenous infusion commencing 5 d after birth of either Intralipid (IL) 10%, IL 20%, or Lipofundin S 20% (LFS; B. Braun, Melsungen, Germany). There were four piglets in each treatment group. IL 10% provides twice as much DHA as IL 20%, while LFS provides no DHA. Protein and other nutrients were provided enterally using a low‐fat milk formula. After 9 d, animals were killed, and the fatty acid compositions of blood, liver, and cerebral cortex were analyzed. IL 10% infusion approximately doubled the amount of plasma phospholipid DHA (μg/mL of plasma) in comparison to IL 20%. However, red blood cells, liver, and cerebral cortex phospholipid DHA levels were indistinguishable between these two groups. LFS was associated with reduced levels of DHA in plasma, red blood cell and liver phospholipids in comparison to IL 20%. We conclude that infusion of additional phospholipid is an ineffective strategy for increasing DHA delivery to piglet tissues. This may be due to the formation of inert phospholipid particles in plasma. The data do not support the concept of using IL 10% as a means of providing additional DHA to premature human infants.
Increased α‐linolenic acid intake increases tissue α‐linolenic acid content and apparent oxidation with little effect on tissue docosahexaenoic acid in the guinea pig
Authors: Fu Zhong , Sinclair Andrew J. 
Published: November 2006

AbstractThe essential fatty acids do not have identical roles in nutrition. Linoleic acid (LA) accumulates throughout the body of most mammals, whereas α‐linolenic acid (ALA) is rarely found in tissue lipids to the same extent as LA. It has been argued that this is the result of metabolism of ALA to docosahexaenoic acid (DHA) or that ALA is rapidly β‐oxidized to acetyl CoA and CO2. In this study, we consider the effect of high and low ALA levels on the tissue distribution of ALA and other n‐3 polyunsaturated fatty acids (PUFA) in all tissues. Guinea pigs were fed one of two defined diets for 3 wk from wearning with both diets containing 1.8% (by weight) of LA and either 1.7% ALA or 0.03% ALA. The high ALA diet was associated with significantly increased ALA levels in all tissues except the brain and significantly increased levels of long‐chain n‐3 PUFA in all tissues except intestines, brain, carcass, and skin. The long‐chain n‐3 PUFA content of the whole body was less than 5% of that of the ALA content in both diet groups, and the major long‐chain n‐3 PUFA (>66% of total) in the body was 22∶5n−3. The brain was the only tissue where the DHA content exceeded that of 22∶5n−3. On the low ALA diet, there appeared to be conservation of ALA based on a comparison of the ratio of LA to ALA in the tissues compared with that in the diet. On the high ALA diet there was a loss of ALA relative to LA in the tissues compared with the diet. These studies suggest that the low levels of tissue ALA in the guinea pig are likely the result of β‐oxidation or excretion via the skin and fur rather than metabolism to DHA.
Effect of n−3 polyunsaturated fatty acid supplementation on lipid peroxidation of rat organs
Authors: Ando Ken , Nagata Kunihide , Yoshida Rie , Kikugawa Kiyomi , Suzuki Masao 
Published: November 2006

AbstractThe present study was undertaken in order to reexamine the effect of n−3 polyunsaturated fatty acid (PUFA)‐rich diet supplementation on lipid peroxidation and vitamin E status of rat organs. Male Wistar rats were fed a diet containing safflower or fish oil at 50 g/kg diet and an equal amount of vitamin E at 59 mg/kg diet (1.18 g/kg oil; and 1.5 g/kg PUFA in safflower oil diet, and 4.3 g/kg PUFA in fish oil diet) for 6 wk. Fatty acid composition of total lipids of brain, liver, heart, and lung of rats fed fish oil was rich in n−3 PUFA, whereas that of each organ of rats fed safflower oil was rich in n−6 PUFA. The vitamin E levels in liver, stomach, and testis of the fish oil diet group were slightly lower than those of the safflower oil diet group, but the levels in brain, heart, lung, kidney, and spleen were not different between the two diet groups. The levels of phospholipid hydroperoxides were determined by the high‐performance liquid chromatography‐chemiluminescence method and the levels of thiobarbituric acid‐reactive substances (TBARS) were determined at pH 3.5 in the presence of butylated hydroxytoluene with or without EDTA. Levels of phospholipid hydroperoxides and TBARS in the brain, liver, heart, lung, kidney, spleen, stomach and testis of the fish oil diet group were similar to those of the safflower oil diet group. The results indicate that high fish oil intake does not induce increased levels of phospholipid hydroperoxides and TBARS in rat organs.
Effects of dietary phenolic compounds on tocopherol, cholesterol, and fatty acids in rats
Authors: Kamal‐Eldin Afaf , Frank Jan , Razdan Alexander , Tengblad Siv , Basu Samar , Vessby Bengt 
Published: November 2006

AbstractThe effects of the phenolic compounds butylated hydroxytoluene (BHT), sesamin (S), curcumin (CU), and ferulic acid (FA) on plasma, liver, and lung concentrations of α‐ and γ‐tocopherols (T), on plasma and liver cholesterol, and on the fatty acid composition of liver lipids were studied in male Sprague‐Dawley rats. Test compounds were given to rats ad libitum for 4 wk at 4 g/kg diet, in a diet low but adequate in vitamin E (36 mg/kg of γ‐T and 25 mg/kg of α‐T) and containing 2 g/kg of cholesterol. BHT significantly reduced feed intake (P<0.05) and body weight and increased feed conversion ratio; S and BHT caused a significant enlargement of the liver (P<0.001), whereas CU and FA did not affect any of these parameters. The amount of liver lipids was significantly lowered by BHT (P<0.01) while the other substances reduced liver lipid concentrations but not significantly. Regarding effects on tocopherol levels, (i) feeding of BHT resulted in a significant elevation (P<0.001) of α‐T in plasma, liver, and lung, while γ‐T values remained unchanged; (ii) rats provided with the S diet had substantially higher γ‐T levels (P<0.001) in plasma, liver, and lung, whereas α‐T levels were not affected; (iii) administration of CU raised the concentration of α‐T in the lung (P<0.01) but did not affect the plasma or liver values of any of the tocopherols; and (iv) FA had no effect on the levels of either homolog in the plasma, liver, or lung. The level of an unknown substance in the liver was significantly reduced by dietary BHT (P<0.001). BHT was the only compound that tended to increase total cholesterol (TC) in plasma, due to an elevation of cholesterol in the very low density lipoprotein + low density lipoprotein (VLDL+LDL) fraction. S and FA tended to lower plasma total and VLDL+LDL cholesterol concentrations, but the effect for CU was statistically significant (P<0.05). FA increased plasma high density lipoprotein cholesterol while the other compounds reduced it numerially, but not significantly. BHT, CU, and S reduced cholesterol levels in the liver TC (P<0.001) and percentages of TC in liver lipids (P<0.05). With regard to the fatty acid composition of liver lipids, S increased the n‐6/n‐3 and the 18∶3/20∶5 polyunsaturated fatty acids (PUFA) ratios, and BHT lowered total monounsaturated fatty acids and increased total PUFA (n−6+n−3). The effects of CU and FA on fatty acids were not highly significant. These results suggest some in vivo interactions between these phenolic compounds and tocopherols that may increase the bioavailability of vitamin E and decrease cholesterol in rats.
Cholesterol‐lowering effects of guar gum: Changes in bile acid pools and intestinal reabsorption
Authors: Moriceau Stéphanie , Besson Catherine , Levrat Marie‐Anne , Moundras Corinne , Rémésy Christian , Morand Christine , Demigné Christian 
Published: November 2006

AbstractSoluble fibers such as guar gum (GG) may exert cholesterol‐lowering effects. It is generally accepted that bile acid (BA) reabsorption in portal blood is reduced, thus limiting the capacity of BA to down‐regulate liver cholesterol 7α‐hydroxylase, the rate‐limiting enzyme of BA synthesis. In the present work, rats were adapted to fiber‐free (FF) or 5% GG diets (supplemented or not with 0.25% cholesterol), to investigate various aspects of enterohepatic BA cycling. GG in the diet at a level of 5% elicited a significant lowering of plasma cholesterol during the absorptive period, in cholesterol‐free (−13%) or 0.25% cholesterol (−20%) diet conditions. In rats adapted to the GG diets, the small intestinal and cecal BA pools and the ileal vein‐artery difference for BA were markedly enhanced; reabsorption in the cecal vein was also enhanced in these rats. [14C]Taurocholate absorption, determined in perfused ileal segments, was not significantly different in rats adapted to the FF or GG diet, suggesting that a greater flux of BA in the ileum might support a greater ileal BA reabsorption in rats adapted to the GG diet. In contrast, capacities for [14C]cholate absorption from the cecum at pH 6.5 were higher in rats adapted to the GG diet than to the FF diet. Acidification of the bulk medium in isolated cecum (from pH 7.1 down to pH 6.5 or 5.8) or addition of 100 mM volatile fatty acids was also found to stimulate cecal [14C]cholate absorption. These factors could contribute to accelerated cecal BA absorption in rats fed the GG diet. The effects of GG on steroid fecal excretion thus appear to accompany a greater intestinal BA absorption and portal flux to the liver. These results suggest that some mechanisms invoked to explain cholesterol‐lowering effect of fibers should be reconsidered.
Changes in liver fatty acid unsaturation after partial hepatectomy in the rat
Authors: Kishino Tomonori , Tanno Munehiko , Yamada Hideo , Saito Shozo , Matsumoto Shigenobu 
Published: November 2006

AbstractThe purpose of this study was to assess changes in the degree of fatty acid unsaturation in rat liver after partial hepatectomy. This is the first study in which liver fatty acid unsaturation has been analyzed over a long period of regeneration until day 28 after operation. The relationship between changes in unsaturation and fatty acid composition in the regenerating liver were also investigated in this study. Proton nuclear magnetic resonance spectroscopy revealed significantly elevated levels of unsaturation with a maximum on day 5 after partial hepatectomy, compared with untreated controls (11.72±0.55 vs. 11.05±0.26%, P<0.05). No significant changes in unsaturation were found in day 1 regenerating liver, which is rich in absolute amounts of fatty acids. Based on gas‐liquid chromatography, the relative amounts of oleic acid (18∶1n−9) and linoleic acid (LA; 18∶2n−6) were increased, while polyunsaturated fatty acids such as arachidonic acid (20∶4n−6) and docosahexaenoic acid (DHA; 22∶6n−3) were decreased on day 1. On the other hand, on day 5 of regeneration, while most fatty acids were returning to their preoperative control levels, only DHA was higher than the control value (7.69±0.58 vs. 5.57±0.37%, P<0.001). The high levels of unsaturation on day 5 were found to be partly due to the increase in DHA. The findings suggest that some significant signals are transmitted during the regeneration process owing to alterations in the membrane structure by the high levels of fatty acid unsaturation and the increase in DHA levels on day 5 after partial hepatectomy.
Esterification of polyunsaturated fatty acids by various forms of immobilized lipase from Rhizomucor miehei
Authors: Kosugi Yoshitsugu , Kumar Roy Prodyut , Chang Qinglong , Shu‐gui Cao , Fukatsu Makoto , Kanazawa Kenji , Nakanishi Hiroshi 
Published: November 2006

AbstractEthyl esterification specificity of a lipase from Rhizomucor miehei for polyunsaturated fatty acids (PUFA) was compared at 1 and 100 mM to study molecular recognition of PUFA. The chemical shift of methylene adjacent to carboxyl groups in the nuclear magnetic resonance spectrum of docosahexaenoic acid (DHA) in ethanol moved to a lower magnetic field as the concentration of DHA increased, suggesting that the degree of dissociation of DHA decreased. Specificity constants or apparent second‐order rate constants (Vmax/Km or catalytic power) for 1 mM esterification by immobilized lipases were higher than the native lipase. Immobilized hydrophobic carrier of low mass transfer resistance for the esterification substrate may improve maximal velocity and affinity for the substrate. Higher specificity constants for 1 mM substrates were observed using immobilized lipases fixed on an anion exchange resin with glutaraldehyde and on a cation exchange carrier with carbodiimide. Activity yields measured with 1 mM PUFA substrate were high. For the substrates at a concentration of 100 mM, higher specific constants with these bifunctional reagents were not observed but higher activity yields were found.
Changes in fatty acid composition in plant tissues expressing a mammalian Δ9 desaturase
Authors: Moon Hangsik , Hazebroek Jan , Hildebrand David F. 
Published: November 2006

AbstractPlant tissues expressing a mammalian stearoyl‐CoA Δ9 desaturase were reported to accumulate Δ9 hexadecenoic acid (16∶1), normally very minor in most plant tissues. The transgenic plants were thoroughly analyzed for alterations of individual lipids in different subcellular sites. Western blot analysis indicated that the animal desaturase was targeted to the microsomes. The Δ9 16∶1 was incorporated into both the sn‐1 and sn‐2 positions of all the major membrane lipids tested, indicating that the endoplasmic reticulum acyltransferases do not exclude unsaturated C16 fatty acids from the sn‐2 position. In addition to increases in monounsaturated and decreases in saturated fatty acids, accumulation of 16∶1 was accompanied by a reduction in 18∶3 in all the lipids tested except phosphatidylglycerol, and increases in 18∶2 in phospholipids. Total C16 fatty acid content in the galactolipids of the transgenics was significantly higher than that in the control, but those in the phospholipids were unchanged. In transgenics, Δ11 18∶1 was detected in the sn‐1 position of the lipids tested except phosphatidylinositol and phosphatidylserine. Introduction of the animal desaturase, controlled by a seed‐specific phaseolin promoter, into soybean somatic embryo resulted in a significant reduction in saturated fatty acids. Such effects were greater in cotyledons than hypocotyl‐radicles. This study demonstrated that the animal desaturase can be used to decrease the levels of saturated fatty acids in a crop plant.
Purification of the acyl‐CoA elongase complex from developing rapeseed and characterization of the 3‐ketoacyl‐CoA synthase and the 3‐hydroxyacyl‐CoA dehydratase
Authors: Domergue Frédéric , Chevalier Sylvette , Créach Anne , Cassagne C. , Lessiré René 
Published: November 2006

AbstractOleoyl‐CoA elongase catalyzes four successive reactions: condensation of malonyl‐CoA to oleoyl‐CoA, reduction, dehydration, and another reduction. Evidence supporting this mechanism and the multienzymatic nature of the elongation complex are reported. A particulate membrane fraction from rapeseed is able to elongate intermediates (R,S) 3‐hydroxy‐20∶0‐CoA and (E) 2,3–20∶1‐CoA to very long chain fatty acids in the presence of malonyl‐CoA. Studies of the 3‐ketoacyl‐CoA synthase activities showed that maximal activity could be measured by using 15 to 30 μM 18∶1‐CoA and 30 μM malonyl‐CoA, and that 18∶0‐CoA and 18∶1‐CoA were the best substrates. Comparison of the condensation and the overall elongation activities indicated that condensation is the rate‐limiting step of the elongation process. The 3‐hydroxyacyl‐CoA dehydratase activity was maximal in the presence of 75 μM Triton X‐100 and 25 μg of proteins. Finally, the acyl‐CoA elongase complex was solubilized and purified. During the purification process, the 3‐hydroxyacyl‐CoA dehydratase copurified with the elongase complex, strongly suggesting that this enzyme belongs to the elongase complex. The apparent molecular mass of 700 kDa determined for the elongase complex, and the fact that four different polypeptide bands were detected after sodium dodecyl sulfate‐polyacrylamide gel electrophoretic analysis of the purified fraction, further suggest that the acyl‐CoA elongase is a multienzymatic complex.
Purification and biochemical characterization of a novel thermostable lipase from Aspergillus niger
Authors: Haridasan Namboodiri Variketta M. , Chattopadhyaya Rajagopal 
Published: November 2006

AbstractAn extracellular 1,3‐specific lipase with molecular weight of 35.5 kDa and an isoelectric point of 4.4 from Aspergillus niger has been purified 50‐fold by pH precipitation followed by a series of chromatographic steps with an overall yield of 10%. The enzyme was homogeneous as judged by denaturing polyacrylamide gel electrophoresis and size‐exclusion fast‐performance liquid chromatography. It contained 2.8% sugar which was completely removed by endoglycosidase F treatment, and the deglycosylated enzyme retained full activity. The native lipase showed optimal activity between temperatures 35 and 55°C and pH 5.0 and 6.0. The amino acid composition and the N‐terminal sequence were found to be different from lipases previously purified from A. niger. The enzyme was resistant to trypsin, chymotrypsin, endoprotease Glu‐C, thrombin, and papain under native conditions but was susceptible to cleavage by the same proteases when heat‐denatured.
Aggregation and fusion of vesicles composed of N‐palmitoyl derivatives of membrane phospholipids
Authors: Mora Margarita , Mir Ferran , de Madariaga M. Africa , Sagrista M. Luisa 
Published: November 2006

AbstractN‐Acylphosphatidylethanolamines and N‐acylphosphatidylserines have been isolated from mammalian cells and have been associated with some tissue degenerative changes, although the relationship between their synthesis and the uncontrolled sequence of events that ends in irreversible tissue damage is not completely established. Our results show that monovalent and divalent cations induce aggregation and fusion of liposomes constituted by N‐palmitoylphosphatidylethanolamine (NPPE) and N‐palmitoylphosphatidylserine (NPPS). The effectiveness of cations to induce the aggregation of NPPE and NPPS liposomes is Ca2+>Mg2+>>Na+. NPPS liposomes aggregate at lower concentrations of divalent cations than NPPE liposomes, but with sodium NPPE liposomes aggregate to a higher extent than NPPS liposomes. The reaction order for the aggregation processes depends on the lipid and the cation nature and range from 1.04 to 1.64. Dynamic light scattering shows an irreversible increase of the size of the aggregates in the presence of all cations tested. The irreversibility of the aggregation process and the intermixing of bilayer lipids, as studied by resonance energy transfer assay, suggest that fusion, rather than aggregation, occurs. The existence of a real fusion was demonstrated by the coalescence of the aqueous contents of both NPPS and NPPE liposomes in the presence of either monovalent or divalent cations. The different binding sensitivity of Ca2+ to NPPS and NPPE liposomes, determined by ş potential measurements, agrees with the results obtained in the aggregation and fusion assays. Our results suggest that the synthesis in vivo of N‐acylated phospholipids can introduce important changes in membrane‐mediated processes.
Characterization of inositol phospholipids and identification of a mastoparan‐induced polyphosphoinositide response in Tetrahymena pyriformis
Authors: Leondaritis George , Galanopoulou Dia 
Published: November 2006

AbstractThe unicellular eukaryote Tetrahymena is a popular model for the study of lipid metabolism. Less attention, however, has been given to the inositol phospholipids of the cell, although it is known that this class of lipids plays an important role in eukaryotic cell signaling. Tetrahymena pyriformis phosphatidylinositol was isolated, purified, and characterized by proton nuclear magnetic resonance analysis and [2‐3H]myoinositol labeling. Labeling was also used for polyphosphoinositide (phosphatidylinositol phosphate and phosphatidylinositol bisphosphate) identification. Tetrahymena inositol phospholipids were found to belong to the diacylglycerol group, although major Tetrahymena phospholipids, phosphatidylcholine and aminoethylphosphonoglycerides, have been found to be mainly alkylacylglyceroderivatives. Further characterization of Tetrahymena phosphatidylinositol by gas chromatographic analysis indicated that 80% of fatty acids were myristic acid and plamitic acid. This is also in contrast to the fatty acid profile of Tetrahymena phosphatidylcholine and phosphatidylethanolamine, with respect both to the fatty acid length and degree of unsaturation, and may indicate that specific diacylglycerol species are connected with the phosphatidylinositol metabolism in this cell. Treatment of [3H]inositol‐labeled Tetrahymena cells with mastoparan, a G‐protein‐activating peptide, induced changes in the polyphosphoinositide levels, suggesting that inositol phospholipids may form in Tetrahymena a functional signaling system similar to that of higher eukaryotes. Addition of 10 μM mastoparan resulted in a rapid and transient increase in [3H]phosphatidylinositol phosphate followed by a decrease in [3H]phosphatidylinositol bisphosphate. Similar changes in lipids have been reported when phosphoinositide‐phospholipase C pathway is activated in both animal and plant cells.
Molecular analysis of intact preen waxes of Calidris canutus (Aves: Scolopacidae) by gas chromatography/mass spectrometry
Authors: Dekker Marlèn H. A. , Piersma Theunis , Sinninghe Damsté Jaap S. 
Published: November 2006

AbstractThe intact preen wax esters of the red knot Calidris canutus were studied with gas chromatography/mass spectrometry (GC/MS) and GC/MS/MS. In this latter technique, transitions from the molecular ion to fragment ions representing the fatty acid moiety of the wax esters were measured, providing additional resolution to the analysis of wax esters. The C21−C32 wax esters are composed of complex mixtures of hundreds of individual isomers. The odd carbon‐numbered wax esters are predominantly composed of even carbon‐numbered n‐alcohols (C14, C16, and C18) esterified predominantly with odd carbon‐numbered 2‐methyl fatty acids (C7, C9, C11, and C13), resulting in relatively simple distributions. The even carbon‐numbered wax esters show a far more complex distribution due to a number of factors: (i) Their n‐alcohol moieties are not dominated by even carbon‐numbered n‐alcohol moieties are not dominated by even carbon‐numbered n‐alcohols esterified with odd carbon‐numbered 2‐methyl fatty acids, but odd and even carbon‐numbered n‐alcohols participate in approximately equal amounts; (ii) odd carbon‐numbered methyl‐branched alcohols participate abundantly in these wax ester clusters; and (iii) with increasing molecular weight, various isomers of the 2,6‐, 2,8‐, and 2,10‐dimethyl branched fatty acids also participate in the even carbon‐numbered wax esters. The data demonstrate that there is a clear biosynthetic control on the wax ester composition although the reasons for the complex chemistry of the waxes are not yet understood.