bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

The 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

The 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

Soluble 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

The 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

Ethyl 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

Plant 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

Oleoyl‐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

An 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

N‐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

The 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

The 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.
Lipids of gelatinous antarctic zooplankton: Cnidaria and Ctenophora
Authors: Nelson Matthew M. , Phleger Charles F. , Mooney Ben D. , Nichols Peter D.
Published: November 2006

Antarctic gelatinous zooplankton, including Cnidaria (Calycopsis borchgrevinki, Diphyes antarctica, Stygiomedusa gigantea, Atolla wyvillei, Dimophyes arctica) and Ctenophora (Beroe cucumis, B. forskalii, Pleurobrachia pileus, Bolinopsis infundibulum) were collected near Elephant Island, South Shetland Islands, during January and February 1997 and 1998. Total lipid was low in all zooplankton (0.1–5 mg g−1 wet mass) and included primarily polar lipids (59–96% of total lipid). Triacylglycerols were 0–26% of total lipids, and wax esters were 0–11% in all species. Cholesterol was the major sterol in all Cnidaria (50–63% of total sterols) whereas in most ctenophores it was lower at 26–45%. These cholesterol levels are consistent with a combined carnivorous and phytoplanktivorous diet in the ctenophores, with the carnivorous diet more dominant in the Cnidaria. Other sterols included primarily trans‐dehydrocholesterol, desmosterol, 24‐methylcholest‐5,22E‐dien‐3β‐ol, 24‐nordehydrocholesterol, and 24‐methylenecholesterol. Total stanols were 0–6% in all zooplankton. Eicosapentaenoic acid and docosahexaenoic acid were the major polyunsaturated fatty acids (PUFA) in all samples (7–25% of total fatty acids) except for A. wyvillei in which docosapentaenoic acid was 10% of total fatty acids. The PUFA 18∶5n−3 was not detected in 1997 samples, but constituted 0.2–0.8% in most 1998 samples. Monounsaturated fatty acids included primarily 18∶1n−9c, 16∶1n−7c, and 18∶1n−7c. The principal saturated fatty acids in all samples were 16∶0, 18∶0, and 14∶0. These data are the first for many of these zooplankton species and the first sterol data for most species. The use of the signature lipid approach has enabled examination of aspects of trophodynamics not obtainable by conventional techniques.
Trans fatty acids in adipose tissue of French women in relation to their dietary sources
Authors: Boué C. , Combe N. , Billeaud C. , Mignerot C. , Entressangles B. , Thery G. , Geoffrion H. , Brun J. L. , Dallay D. , Leng J. J.
Published: November 2006

This study reports the fatty acid composition of subcutaneous adipose tissue in French women with special emphasis on the content of trans fatty acids originating from two main dietary sources, ruminant fats and partially hydrogenated vegetable oils (PHVO). Adipose tissue trans fatty acid levels from 71 women, recruited between 1997 and 1998, were determined using a combination of capillary gas chromatography and silver nitrate thin‐layer chromatography. Results indicate that on average cis monounsaturates accounted for 47.9% of total fatty acids, saturates for 32.2%, and linoleic acid for 14.4%. Cis n−3 polyunsaturates represented only 0.7%. Total content of trans fatty acids was 2.32±0.50%, consisting of trans 18∶1 (1.97±0.49%), trans 18∶2 (0.28±0.08%), and trans 16∶1 (0.06±0.03%). Trans 18∶3 isomers were not detectable. The level of trans fatty acids found in adipose tissue of French women was lower than those reported for Canada, the United States, and Northern European countries but higher than that determined in Spain. Therefore, trans fatty acid consumption in France appears to be intermediate between that of the United States or North Europe and that of Spain. Based on the equation of Enig et al., we estimated the mean daily trans 18∶1 acid intake of French women at 1.9 g per person. The major trans 18∶1 isomer in adipose tissue was Δ11trans, as in ruminant fats. Estimates of relative contribution of trans fatty acid intake were 55% from ruminant fats and 45% from PHVO. This pattern contrasts sharply with those established for Canada and the United States where PHVO is reported to be the major dietary source of trans fatty acids.
Reinvestigation of positional distribution of fatty acids in docosahexaenoic acid‐rich fish oil triacyl‐sn‐glycerols
Authors: Ando Yasuhiro , Satake Motoi , Takahashi Yoichi
Published: November 2006

Positional distribution of fatty acids in triacyl‐sn‐glycerols of docosahexaenoic acid (DHA)‐rich tuna orbital and bonito head oils has been reanalyzed by a method based on chromatographic separation of isomeric and enantiomeric monoacyl‐sn‐glycerol (MAG) derivatives. When boric acid thinlayer chromatography (TLC) was used for separation of 1(3)‐ and 2‐MAG analytical intermediates, the stereospecific analysis showed the preferential association of DHA to the sn‐2 position followed by the sn‐3 position. This distribution pattern differed from that obtained by silicic acid LTC of their bis‐3,5‐dinitrophenylurethane (DNPU) derivatives. Reversed‐phase high‐performance liquid chromatography elution profiles of 1(3)‐ and 2‐MAG intermediates revealed that 1(3)‐ and 2‐MAG made up of both short‐ and long‐chain lengths cannot be clearly resolved by TLC after preparation of the DNPU derivatives. The 1(3)‐ and 2‐MAG must be resolved by boric acid TLC prior to derivatization.
Effect of a low‐fat diet enriched with oleic acid on postprandial lipemia in patients with type 2 diabetes mellitus
Authors: Higashi Kenji , Shige Hideki , Ito Toshimitsu , Nakajima Kei , Ishikawa Toshitsugu , Nakamura Haruo , Ohsuzu Fumitaka
Published: November 2006

The aim of the present study was to compare the effects of a low‐fat diet enriched with oleic acid to those of a low‐fat diet enriched with linoleic acid on fasting lipids, postprandial lipemia, and oxidative susceptibility of low‐density lipoprotein (LDL) in patients with type 2 diabetes mellitus (DM). In a 3‐wk randomized crossover study, eight patients with type 2 DM were given an experimental low‐fat diet enriched with either oleic acid or linoleic acid. The oleic‐acid‐enriched diet contained 5, 15, and 5% energy from saturated, monounsaturated, and polyunsaturated fatty acids, and the linoleic‐acid‐enriched diet contained 5, 5, and 15% energy from saturated, monounsaturated, and polyunsaturated fatty acids, respectively. In addition to evaluating the fasting lipids and oxidative susceptibility of LDL, we evaluated postprandial lipemia using an oral fat load at the end of each 3‐wk dietary phase. There were no significant differences in fasting lipid profile or lag time of LDL oxidation between the two experimental dietary phases. The average and maximal increments of remnant‐like particle (RLP) cholesterol levels during oral fat load were significantly higher after the oleic‐acid‐enriched dietary phase than after the linoleic‐acid‐enriched dietary phase. The area under the curve of RLP cholesterol was also significantly larger after the oleicacid‐enriched dietary phase than after the linoleic‐acid‐enriched dietary phase. These results suggest that the oleic‐acidenriched diet was associated with increased formation of postprandial chylomicron remnants compared with the linoleicacid‐enriched diet.
A long‐term seal‐ and cod‐liver‐oil supplementation in hypercholesterolemic subjects
Authors: Brox Jan , Olaussen Kirsten , Østerud Bjarne , Elvevoll Edel O. , Bjørnstad Eivin , Brenn Tormod , Brattebø Guttorm , Iversen Hanne
Published: November 2006

In this long‐term study, we wanted to explore the effect of dietary supplementation of seal oil (SO) as compared cod‐liver oil (CLO) on subjects with moderate hypercholesterolemia. The test parameters included fatty acid composition in serum, blood lipids, platelet aggregation, and the activity of blood monocytes. After a run‐in period of 6 mon, 120 clinically healthy hypercholesterolemic (7.0–9.5 mmol/L; 270–366 mg/dL) subjects were randomly selected to consume either 15 mL of SO or CLO daily for 14 mon followed by a 4‐mon wash‐out period. A third group was not given any dietary supplement (control). Consumption of marine oils (SO and CLO) changed the fatty acid composition of serum significantly. Maximal levels were achieved after 10 mon. No further changes were seen after 14 mon. A wash‐out period of 4 mon hardly altered the level of n−3 fatty acids in serum. Addition of SO gave 30% higher level of eicosapentaenoic acid, as compared to CLO. Subjects taking SO or CLO had lower whole‐blood platelet aggregation than the control group. Neither SO nor CLO had any effects on the levels of serum total cholesterol, high‐density lipoprotein cholesterol, postprandial triacylglycerol, apolipoproteins A1 and B100, lipoprotein (a), monocyte function expressed as monocyte‐derived tissue factor expression, and tumor necrosis factor.
Modulation of apolipoprotein E‐mediated plasma clearance and cell uptake of emulsion particles by cholesteryl ester
Authors: Saito Hiroyuki , Okuhira Keiichirou , Tsuchimoto Nanoko , Vertut‐Doï Aline , Matsumoto Chizuko , Tanimoto Tsuyoshi , Okada Satoshi , Handa Tetsurou
Published: November 2006

Cholesteryl ester, along with triglyceride (TG), is the major core component of plasma lipoproteins. We investigated the effect of core composition on the physical state and metabolic behavior of lipid emulsions, as model particles of lipoproteins. Fluorescence studies using 1,6‐diphenylhexatriene analogs showed that although cholesteryl oleate (CO) significantly decreased core mobility, the surface rigidity of phosphatidylcholine (PC) monolayers was independent of core composition. When intravenously injected into rats, the increased amount of core CO tended to retard TG emulsion removal from plasma, and the initial clearance rate was correlated with the amount of apolipoprotein E (apoE) bound from plasma. In addition, PC liposomes with a similar emulsion particle size showed negligible binding of apoE and were cleared at a slower rate compared to all emulsions. Furthermore, the effect of CO on the binding behavior of apoE to the emulsion surface and the emulsion uptake by hepatocytes was assessed in vitro. Replacing core TG with CO was found to decrease the apoE binding capacity to emulsions markedly without changing the binding affinity and thereby to reduce the cell uptake of emulsion particles by HepG2 cells. These results indicate that the physical state of core lipids, which can be modulated by cO content, plays a role in emulsion metabolism through the alteration in apoE binding.
α‐ and γ‐tocotrienols are metabolized to carboxyethyl‐hydroxychroman derivatives and excreted in human urine
Authors: Lodge John K. , Ridlington James , Leonard Scott , Vaule Heather , Traber Maret G.
Published: November 2006

Limited information is available regarding metabolism of vitamin E forms, especially the tocotrienols. Carboxyethyl‐hydroxychromans (α‐and γ‐CEHC) are human urinary metabolites of α‐ and γ‐tocopherols, respectively. To evaluate whether tocotrienols are also metabolized and excreted as urinary CEHC, urine was monitored following tocotrienol supplementation. Complete (24 h) urine collections were obtained for 2 d prior to (baseline), the day of, and 2 d after human subjects (n=6) ingested tocotrienol supplements. The subjects consumed 125 mg γ‐tocotrienyl acetate the first week, then the next week 500 mg; then 125 mg α‐tocotrienyl acetate was administered the third week, followed by 500 mg the fourth week. Urinary α‐ and γ‐CEHC were measured by high‐performance liquid chromatography with electrochemical detection. Urinary γ‐CEHC levels rose about four‐ to sixfold in response to the two doses of γ‐tocotrienol and then returned to baseline the following day. Significant (P<0.0001) increases in urinary α‐CEHC were observed only following ingestion of 500 mg α‐tocotrienyl acetate. Typically, 1–2% of α‐tocotrienyl acetates or 4–6% of γ‐tocotrienyl acetates were recovered as their respective urinary CEHC metabolites. A γ‐CEHC excretion time course showed an increase in urinary γ‐CEHC at 6 h and a peak at 9 h following ingestion of 125 mg γ‐tocotrienyl acetate. In summary, tocotrienols, like tocopherols, are metabolized to CEHC; however, the quantities excreted in human urine are small in relation to dose size.
Removal of fat from Cow's milk decreases the vitamin E contents of the resulting dairy products
Authors: Kaushik Supriya , Wander Rosemary , Leonard Scott , German Bruce , Traber Maret G.
Published: November 2006

The present study was undertaken to determine whether decreases in fat contents result in lower vitamin E contents. Milk samples of varying fat contents (half and half, whole milk, reduced‐fat milk low‐fat milk, and nonfat milk) were obtained from a local dairy on six different occasions, α‐locopherol was the major form of vitamin E (>85%); γ‐tocopherol and α‐tocotrienol were present to a lesser extent. As the fat contents of milk products decreased from 11 to 0.3%, the vitamin E contents decreased. For example, raw milk as compared to nonfat milk had both higher α‐tocopherol contents (45.5+‐4.6 vs. 4.5±0.5 μg/100 g; P<‐0.0001) and higher total lipids (3.46±0.49 vs. 0.30±0.07 g/100 g; P≤0.0001). Vitamin E, cholesterol, and total lipids increased as cream was added back to nonfat milk during production. For every 1 mg cholesterol increase, there was an increase of approximately 4 μg of α‐tocopherol; for every 1 g total lipids increase, the α‐tocopherol content increased by 17 μg. These data demonstrate that removal of milk fat markedly decreases the vitamin E content of various milk products
Biosynthesis of eicosapentaenoic acid in the sea urchin Psammechinus miliaris
Authors: Bell Michael V. , Dick James R. , Kelly Maeve S.
Published: November 2006

The sea urchin Psammechinus miliaris (Gmelin) (Echinodermata: Echinoidea) was shown by using a deuterated tracer (D5−18∶3n−3) and quantitation by negative chemical ionization gas chromatography‐mass spectrometry to convert 18∶3n−3 to 20∶5n−3. The rate of conversion was very slow, corresponding to 0.09 μg/g tissue/mg 18∶3n−3 eaten over 14 d. Deuterated arachidonic acid (D8−20∶4n−6) was also included in the diet to give a measure of the relative amounts of diet eaten by the different animals. The recovery of this fatty acid in tissue lipids was 33.7% compared with only 0.95% recovery of D5−18∶3n−3 and its anabolites, indicating that the majority of the D5‐tracer was catabolized. Considerable elongation of D5−18∶3n−3 into 20∶3n−3 and a trace of 22∶3n−3 was found, and these were accompanied by minor amounts of the intermediates 18∶4n−3 and 20∶4n−3. No deuterated 22∶6n−3 was found.
Major clofibrate effects on liver and plasma lipids are independent of changes in polyunsaturated fatty acid composition induced by dietary fat
Authors: Pennacchiotti Graciela L. , Maldonado Eduardo N. , Aveldaño Marta I.
Published: November 2006

The effects of clofibrate on the content and composition of liver and plasma lipids were studied in mice fed for 4 wk on diets enriched in n−6 or n−3 polyunsaturated fatty acids (PUFA) from sunflower oil (SO) or fish oil (FO), respectively; both oils were fed at 9% of the diet (dry weight basis). Only FO was hypolipidemic. Both oil regimes led to slightly increased concentrations of phospholipids (PL) and triacylglycerols (TG) in liver as compared with a standard chow diet containing 2% fat. Clofibrate promoted hypolipidemia only in animals fed SO. Its main effect was to enlarge the liver, such growth increasing the amounts of major glycerophospholipids while depleting the TG. SO and FO consumption changed the proportion of n−6 or n−3 PUFA in liver and plasma lipids in opposite ways. After clofibrate action, the PUFA of liver PL were preserved better than in the absence of oil supplementation. However, most of the drug‐induced changes (e.g., increased 18∶1n−9 and 20∶3n−6, decreased 22∶6/20∶5 ratios) occurred inrrespective of lipids being rich in n−6 or n−3 PUFA. The concentration of sphingomyelin (SM), a minor liver lipid that virtually lacks PUFA, increased with the dietary oils, decreased with clofibrate, and changed its fatty acid composition in both situations. Thus. oil‐increased SM had more 22∶0 and 24∶0 than clofibrate‐decreased SM, which was significantly richer in 22∶1 and 24∶1.
Dietary supplementation with conjugated linoleic acid does not alter the resistance of mice to Listeria monocytogenes infection
Authors: Turnock Lori , Cook Mark , Steinberg Howard , Czuprynski Charles
Published: November 2006

Conjugated linoleic acid (CLA) has been used experimentally as a dietary supplement to increase lean body weight and to modulate inflammation in a variety of animal species. In addition, human use of dietary CLA as a supplement to regulate body fat has received both scientific and public attention. No reports have been published regarding the effects of dietary CLA on antimicrobial resistance. In this study, we provide evidence that feeding CLA for up to 4 wk does not alter host defense against Listeria monocytogenes in mice. These findings suggest that the anti‐inflammatory effects of CLA do not impair cellular immunity to this intracellular pathogen.
Effect of conjugated linoleic acid on fungal Δ6‐desaturase activity in a transformed yeast system
Authors: Chuang Lu‐Te , Thurmond Jennifer M. , Liu Jim‐Wen , Kirchner Stephen I. , Mukerji Pradip , Bray Tammy M. , Huang Yung‐Sheng
Published: November 2006

Conjugated linoleic acid (CLA; 18∶2), a group of positional and geometric isomers of linoleic acid (LA; 18∶2n−6), has been shown to modulate immune function through its effect on eicosanoid synthesis. This effect has been attributed to a reduced production of n−6 polyunsaturated fatty acid (PUFA), the precursor of eicosanoids. Since Δ6‐desaturase is the rate‐limiting enzyme of the n−6 PUFA production, it is our hypothesis that CLA, which has similar chemical structure to LA, interacts directly with Δ6‐desaturase. A unique and simple model, i.e., baker's yeast (Saccharomyces cerevisiae) transformed with fungal Δ6‐desaturase gene, previously established, was used to investigate the direct effect of CLA on Δ6‐desaturase. This model allows LA to be converted to γ‐linolenic acid (GLA; 18∶3n−6) but not GLA to its metabolite(s). No metabolites of CLA were found in the lipids of the yeast transformed with Δ6‐desaturase. The inability to convert CLA to conjugated GLA was not due to the failure of yeast cells to take up the CLA isomers. CLA mixture and individual isomers significantly inhibited the activity of Δ6‐desaturase of the transformed yeast in vivo. Even though its uptake by the yeast was low, CLA c9, t11 isomer was found to be the most potent inhibitor of the four isomers tested, owing to its high inhibitory effect on Δ6‐desaturase. Since CLA did not cause significant changes in the level of Δ6‐desaturase mRNA, the inhibition of GLA production could not be attributed to suppression of Δ6‐desaturate gene expression at the transcriptional level.
Cultured fish cells metabolize octadecapentaenoic acid (all‐cis δ3,6,9,12,15–18∶5) to octadecatetraenoic acid (all‐cis δ6,9,12,15–18∶4) via its 2‐trans intermediate (trans δ2, all‐cis δ6,9,12,15–18∶5)
Authors: Ghioni C. , Porter A. E. A. , Sadler I. H. , Tocher D. R. , Sargent J. R.
Published: November 2006

Octadecapentaenoic acid (all‐cis δ3,6,9,12,15–18∶5; 18∶5n−3) is an unusual fatty acid found in marine dinophytes, haptophytes, and prasinophytes. It is not present at higher trophic levels in the marine food web, but its metabolism by animals ingesting algae is unknown. Here we studied the metabolism of 18∶5n−3 in cell lines derived from turbot (Scophthalmus maximus), gilthead sea bream (Sparus aurata), and Atlantic salmon (Salmo salar). Cells were incubated in the presence of approximately 1 μM [U‐14C] 18∶5n−3 methyl ester or [U‐14C]18∶4n−3 (octadecatetraenoic acid; all‐cis δ6,9,12,15–18∶4) methyl ester, both derived from the alga Isochrysis galbana grown in H14CO3−, and also with 25 μM unlabeled 18∶5n−3 or 18∶4n−3. Cells were also incubated with 25 μM trans δ2, all‐cis δ6,9,12,15–18∶5 (2‐trans 18∶5n−3) produced by alkaline isomerization of 18∶5n−3 chemically synthesized from docosahexaenoic acid (all‐cis δ4,7,10,13,16,19–22∶6). Radioisotope and mass analyses of total fatty acids extracted from cells incubated with 18∶5n−3 were consistent with this fatty acid being rapidly metabolized to 18∶4n−3 which was then elongated and further desaturated to eicosatetraenoic acid (all‐cis δ8,11,14,17,19–20∶4) and eicosapentaenoic acid (all‐cis δ5,8,11,14,17–20∶5). Similar mass increases of 18∶4n−3 and its elongation and further desaturation products occurred in cells incubated with 18∶5n−3 or 2‐trans 18∶5n−3. We conclude that 18∶5n−3 is readily converted biochemically to 18∶4n−3 via a 2‐trans 18∶5n−3 intermediate generated by a Δ3, Δ2‐enoyl‐CoA‐iso‐merase acting on 18∶5n−3. Thus, 2‐trans 18∶5n−3 is implicated as a common intermediate in the β‐oxidation of both 18∶5n−3 and 18∶4n−3.
Characterization of N‐acylphosphatidylethanolamine and acylphosphatidylglycerol in oats
Authors: Holmback Jan , Karlsson Anders , Arnoldsson Kristina C.
Published: November 2006

Two polar lipid classes, both with three acyl groups, were isolated from an extract of oats and characterized by nuclear magnetic resonance spectroscopy, electrospray mass spectrometry (MS), and electron ionization MS (EIMS). Distortionless enhancement by polarization transfer (DEPT) and the two‐dimensional correlation experiments 1H‐detected heteronuclear multiple quantum coherence spectroscopy, heteronuclear multiple bond correlation spectroscopy, double quantum filtered correlation spectroscopy, and total correlation spectroscopy provided sufficient information for determination of the structure of the two lipid classes. The polar lipid classes were found to be N‐acylphosphatidylethanolamine [1,2‐diacyl‐sn‐glycero‐3‐phospho‐(N‐acyl)‐1′‐ethanolamine; N‐acyl‐PE] and acylphosphatidylglycerol [1,2‐diacyl‐sn‐glycero‐3‐phospho‐(3′‐acyl)‐1′‐sn‐glycerol]. High‐performance liquid chromatography with electrospray ionization MS (HPLC‐ESMS) and with electrospray ionization tandem MS (HPLC‐MS/MS) were utilized for the separation and subsequent determination of molecular species. With HPLC‐ESMS, ions of deprotonated molecules were obtained and with HPLC‐MS/MS carboxylate ions (representin acyl groups) were obtained as well as other structurally significant ions. Fifty molecular species of N‐acylphosphatidylethanolamine and 24 molecular species of acylphosphatidylglycerol were found, with a molecular mass range of 924–1032 Da and 959–1035 Da, respectively. Identification of the fatty acid isomers, as picolinyl ester derivatives, was done with gas chromatography with EIMS. Three isomers of 16∶1 fatty acids were found in N‐acyl‐PE and their double bond positions were determined to 6, 9 and 11 with a relative abundance of 4∶10∶1.
Fatty acid composition of lipids present in selected lichenized fungi: A chemotyping study
Authors: Sassaki Guilherme L. , Cruz Leonardo M. , Gorin Philip A. J. , Iacomini Marcello
Published: November 2006

The total‐lipid composition of 21 lichens of the ascomycetous genera Cladonia (11) and Cladina (1) of the family Cladoniacea, Cladia (1), Parmotrema (3), Ramalina (2), Leptogium (1), Cetraria (1), and the basidiomycetous genus Dictyonema (1) was determined. Analyses of those of Dictyonema glabratum were carried out with a total extract and those obtained after successive extractions with various solvents. Each extract was partitioned between n‐heptane/isopropanol and 1 M sulfuric acid, giving triglycerides (TG) in the upper phase. Extracts were methanolyzed and the resulting methyl esters were analyzed by gas chromatography‐mass spectrometry. Methanolyzates of TG unexpectedly contained esters of 9‐oxodecanoic, 9‐methyl‐tetradecanoic, 6‐methyl‐tetradecanoic, 3‐hydroxy‐decanoic, nonanedioic, and decanedioic acids, as well as common fatty acids. Fatty acid methyl ester profiles from the lichens were submitted to cluster analysis, and the resulting dendogram showed a cluster consistent with Cladonia spp., suggesting an efficient aid to lichen taxonomy. The total carbohydrate content of each lipid extract was determined by a modified phenol‐sulfuric acid method, which compensated for the presence of pigments.
A new ceramide from the basidiomycete Russula cyanoxantha
Authors: Gao Jin‐Ming , Dong Ze‐Jun , Liu Ji‐Kai
Published: November 2006

A new phytosphingosine‐type ceramide (1) was isolated along with nine other compounds—5α,8α‐epidioxy‐(22E,24R)‐ergosta‐6,22‐dien‐3β‐ol, 5α,8α‐epidioxy‐(24S)‐ergosta‐6‐en‐3β‐ol, (24S)‐ergosta‐7‐ene‐3β,5α,6β‐triol,(22E,24R)‐ergosta‐7, 22‐dien‐3β,5α,6β‐triol, inosine, adenine, l‐pyroglutamic acid, fumaric acid, and d‐allitol from the ethanol and chloroform/methanol extract of the fruiting bodies of the basidiomycete Russula cyanoxanotha (Schaeff.) Fr. The structure of (1) was established as (2S,3S,4R,2′R)‐2‐(2′‐hydroxytetracosanoylamino) octadecane‐1,3,4‐triol by means of spectroscopic and chemical methods.
Ab initio and density functional theory studies for the explanation of the antioxidant activity of certain phenolic acids
Authors: Bakalbassis Evangelos G. , Chatzopoulou Argero , Melissas Vasilios S. , Tsimidou Maria , Tsolaki Matina , Vafiadis Anastasios
Published: November 2006

Ab initio and density functional theory molecular orbital calculations were carried out at both the HF/6‐31+G(d) and B3LYP/6‐31+G(d) levels for the four antioxidants, p‐hydroxycinnamic acid derivatives, namely, the p‐coumaric, caffeic, ferulic, and sinapinic acid and the corresponding radicals, in an attempt to explain the structural dependency of the antioxidant activity of these compounds. Optimized resulting geometries, vibrational frequencies, absolute infrared intensities, and electron‐donating ability are discussed. Both the high degree of conjugation and the extended spin delocalization in the phenoxyl radicals offer explanation for the scavenging activity of the four acids. In structurally related compounds, the calculated heat of formation value in radical formation appears as a meaningful molecular descriptor of antioxidant activity in accordance with experimental data. This becomes more clear at the B3LYP level.