bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of brominated long‐chain fatty acids from the phospholipids of the tropical marine spongeAmphimedon terpenensis
Authors: Garson Mary J. , Zimmermann Mary P. , Hoberg Max , Larsen Rundi M. , Battershill Christopher N. , Murphy Peter T. 
Published: November 2006

AbstractPreliminary investigation of the phospholipid fatty acid composition of the tropical marine spongeAmphimedon terpenensis by gas chromatography/mass spectrometry revealed the presence of some novel brominated fatty acids. Two new brominated fatty acids, (5E, 9Z)‐6‐bromo‐5,9‐tetracosadienoic acid (2a) and (5E, 9Z)‐6‐bromo‐5,9‐pentacosadienoic acid (3a) were subsequently isolated from a chloroform/methanol (3∶1, vol/vol) extract of the sponge and characterized as their methyl esters 2b and 3b. The known brominated fatty acid (5E, 9Z)‐6‐bromo‐5,9‐hexacosadienoic acid (4a) was also isolated. The new fatty acid methyl esters were confirmed as brominated δ5,9 acid derivatives by chemical ionization mass spectrometry. The position of the bromine substituent was determined to be C‐6 by nuclear magnetic resonance techniques while the stereochemistry of the two double bonds was deduced by nuclear Overhauser enhancement difference spectroscopy. The biosynthetic implications of the co‐occurrence of the three brominated acids are discussed.
Oxidations of the α‐tocopherol model compound 2,2,5,7,8‐pentamethyl‐6‐chromanol. Formation of 2,2,7,8‐tetramethylchroman‐5,6‐dione
Authors: Kohar Indrajati , Suarna Cacang , Southwell‐Keely Peter T. 
Published: November 2006

AbstractOveroxidation of α‐tocopherol (1a) by silver nitrate produces tocored (9a) as a major product. The aim of the present work was to elucidate the pathway of formation of tocored using the α‐tocopherol model compound, 2,2,5,7,8‐pentamethyl‐6‐chromanol (1b). Oxidation of 1b by silver nitrate in ethanol produces 2‐(3‐hydroxy‐3‐methylbutyl)‐3,5,6‐trimethyl‐1,4‐benzoquinone (6b) and 2,2,7,8‐tetramethylchroman‐5,6‐dione (9b, the model compound of tocored) as major products. Formation of 6b is rapid and is accompanied by an equally rapid fall in pH. Formation of 9b only occurs after 6b has reached maximum concentration and has begun to decline. It appears that acid promotes the dehydration and recyclization of 6b into a quinone methide (2b), which is then rehydrated into 5‐hydroxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol (5b), the phenolic isomer of the quinone 6b. Oxidative deformylation of 5b leads to 9b. It is also demonstrated that 6b, heated in ethanol in the presence of acid and in the absence of any oxidizing agent, is converted into 9b, 1b, 5‐ethoxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol (4b) and 2‐(3‐hydroxy‐3‐methylbutyl)‐3‐ethoxymethyl‐5,6‐dimethyl‐1,4‐benzoquinone (7b). It seems that dehydration and recyclization of 6b into 5b occurs as above and that 6b then oxidizes 5b into 9b, while being reduced into the hydroquinone of 6b (6bH2). Compound 6bH2 then cyclizes in acid to 1b. A possible alternative pathway from 6b to 9b that does not involve 5b is also discussed. These results suggest that 6b and, by implication, α‐tocopheryl quinone (6a), is not a stable compound and, in the presence of acid, is readily oxidized to 9b.
Synthesis and antitumor activity of 1‐β‐D‐arabinofuranosylcytosine conjugates of optical isomers of ether and thioether lipids
Authors: Hong Chung , An Seung‐Ho , Nechaev Alexander , Kirisits Alan J. , Vig Rakesh , West Charles R. 
Published: November 2006

AbstractFour 1‐β‐D‐arabinofuranosylcytosine conjugates (ara‐C) (1a, b and 2a, b) ofsn−1 andsn−3 isomers of 1‐O‐octadecyl‐2‐O‐palmitoylglycerol and its 1‐S‐alkyl analogue have been synthesized, and their antitumor activity against L1210 lymphoid leukemia in mice were compared with those of the previous conjugates (3a, b) of racemates in order to determine the significance of chirality of the glycerol moieties for activity. Administration (i.p.) of a single dose (300 mg/kg) of conjugates ofsn−1 (1a),sn−3 (2a) andrac (3a) isomers of the ether lipid increased lifespan of i.p. implanted L1210 lymphoid leukemic DBA/2J mice by 169, 175 and 236%, respectively. Thesn−1 (1b),sn−3 (2b), andrac (3b) isomers of the thioether lipid with a single dose of 300 mg/kg produced an increase in lifespan values of 238, 263 and 250%, respectively. The results indicate that chirality of the glycerol moieties appears not to be critical for the activity, and racemates 3a and 3b are promising prodrugs of ara‐C for further clinical investigations.
Application of paired‐ion high‐performance liquid chromatography to the separation of molecular species of phosphatidylinositol
Authors: Nakagawa Yasuhito 
Published: November 2006

AbstractA paired‐ion high‐performance liquid chromatographic (HPLC) procedure was developed for the separation of individual molecular species of phosphatidylinositol (PI) without prior derivatization. The separation is accomplished on a reverse‐phase column using acetonitrile, methanol and 10 mM tetrabutylammonium phosphate as mobile phase. Separation of the major molecular species of soybean PI by HPLC is achieved within 60 min. The method is applicable to analytical and metabolic studies on PI and has the advantage that the entire PI structure is preserved, as no degradation or derivatization procedures are involved.
Separation and identification of isomeric conjugated fatty acids by high‐performance liquid chromatography with photodiode array detection
Authors: Husain Sajid , Devi K. Sita 
Published: November 2006

AbstractA simple, high‐performance liquid chromatographic method is described for the separation of tetraenoic, trienoic and dienoic conjugated fatty acids on a Zorbax ODS reversed‐phase column using acetonitrile/tetrahydrofuran (95∶5, vol/vol) at a flow rate of 1.2 mL/min as mobile phase. Also described is the separation of the isomeric conjugated fatty acids with acetonitrile/water/tetrahydrofuran (90∶90∶1, by vol) as mobile phase. The simultaneous detection and identification of the separated geometrical isomers in the eluant was accomplished using photodiode array detection.
Reevaluation of the neutral lipids ofTilletia controversa andTilletia tritici
Authors: Beattie S. E. , Stafford A. E. , King A. D. 
Published: November 2006

AbstractDifferential scanning calorimetry of whole teliospores and lipid extracts ofTilletia controversa Kühn andT. tritica Tul. indicated that the lipid composition of teliospores was different than earlier reported. An exothermic peak at −40 to −45°C and an endotherm at −25 to −15°C indicated that the majority of lipids were triacylglycerols (TAG). Hot isopropanol was used to inactivate lipases during lipid extraction. Thin‐layer chromatographic analysis of extracted lipids showed that free fatty acids (FFA) were not present in great quantities unless water was present during lipid extraction. As measured by gas chromatography. FFA accounted for 1–5% of the lipid content in teliospores ofTilletia spp. The TAG content of teliospores was 60–80% of total lipids.
The effect of dietary n−3 polyunsaturated fatty acids on HDL cholesterol in Chukot residentsvsmuscovites
Authors: Gerasimova E. , Perova N. , Ozerova I. , Polessky V. , Metelskaya V. , Sherbakova I. , Levachev M. , Kulakova S. , Nikitin Yu. , Astakhova T. 
Published: November 2006

AbstractNative Chukot Peninsula residents, in contrast to Muscovites, consume a diet rich in n−3 polyunsaturated fatty acids. This dietary peculiarity is reflected in differences in plasma lipid and apolipoprotein contents. The Chukot residents have lower contents of total cholesterol, triglyceride, LDL (low density lipoprotein) cholesterol and apolipoprotein B, but higher HDL (high density lipoprotein) cholesterol levels than do Muscovites. The apolipoprotein A‐I levels were identical in both groups. A higher HDL cholesterol to apolipoprotein A‐I ratio was determined in the coastline Chukot residents (0.52±0.01) than in Muscovites (0.43±0.01; p<0.01). In contrast to Muscovites, the coastline Chukot residents also had higher n−3 and lower n−6 polyunsaturated fatty acid percentages in plasma and erythrocyte lipids, and lower phosphatidylcholine and higher sphingomyelin or phosphatidylethanolamine levels in HDL2band HDL3. The higher HDL cholesterol levels in the plasma of the coastline Chukot residents appears to reflect the higher cholesterol‐scavenging capacity of their HDL.We conclude from this study that the regular consumption of dietary n−3 polyunsaturated fatty acids by the coastline Chukot residents decreased LDL cholesterol transfer from plasma to peripheral cells, and enhanced cholesterol efflux from cellular membranes toward HDL.
Eicosapentaenoic acid inhibits tube formation of vascular endothelial cellsin vitro
Authors: Kanayasu Toshie , Morita Ikuo , Nakao‐Hayashi Junko , Asuwa Noriko , Fujisawa Chiho , Ishii Toshiharu , Ito Hideki , Murota Sei‐itsu 
Published: November 2006

AbstractWe previously have described a quantitative angiogenesisin vitro model, in which endothelial cells are cultured between two layers of type I collagen gel and become organized into tube‐like structures. Using this model, the effect of eicosapentaenoic acid (20∶5n−3) on tube formation was investigated. When the endothelial cells isolated from bovine carotid artery were treated for 2 days with 5 μg/mL of arachidonic acid (20∶4n−6), eicosapentaenoic acid or docosahexaenoic acid (22∶6n−3), these polyunsaturated fatty acids were extensively incorporated into cellular phospholipids. The content of arachidonic, eicosapentaenoic and docosahexaenoic acid increased from 9.58% to 23.29%, from 0.98% to 11.76% and from 6.88% to 18.40%, respectively. When the eicosapentaenoic acid‐treated cells were cultured between collagen gels, the tube‐forming ability of the cells was markedly inhibited. The inhibition was dose‐dependent between 1.0 and 5.0 μg/mL of eicosapentaenoic acid. At 5.0 μg/mL of eicosapentaenoic acid the inhibition reached 76%. By contrast, arachidonic acid increased tube formation, and docosahexaenoic acid had no effect. To elucidate the mechanism of eicosapentaenoic acid induced inhibition ofin vitro tube formation, we examined the effect of the acid on the proliferation of endothelial cells. Eicosapentaenoic acid at any dose (<5.0 μg/mL) had no effect on the proliferation of endothelial cells cultured on plastic plates without collagen gel. However, when the cells were cultured between collagen gels, eicosapentaenoic acid inhibited cell growth in a dose‐dependent manner with maximum inhibition being observed at 2.5 μg/mL. These data suggest that eicosapentaenoic acid suppresses tube formation of endothelial cells, at least in part,via its inhibitory effect on cellular proliferation. Thus eicosapentaenoic acid may act as an endogenous inhibitor of angiogenesis under various pathological conditions, including tumor growth and chronic inflammation.
Preparation of methyl 11,14,17‐eicosatrienoate‐8,8,9,9‐d4 and methyl 8,11,14,17‐eicosatetraenoate‐8,9‐d2
Authors: Rakoff Henry 
Published: November 2006

AbstractMethyl 11,14,17‐eicosatrienoate‐8,8,9,9‐d4 was obtained by Wittig coupling of 3,6‐nonadienyltriphenylphosphonium iodide with methyl 11‐oxoundecanoate‐8,8,9,9‐d4. For the synthesis of the phosphonium salt, 2‐pentynol was converted to 1‐bromo‐2‐pentyne with triphenylphosphine dibromide. Grignard coupling of 1‐bromo‐2‐pentyne with 3‐butynol in the presence of cuprous chloride gave 3,6‐nonadiynol. The latter was hydrogenated in the presence of P‐2 nickel catalyst to yield 3,6‐nonadienol. The dienol was convertedvia the bromide and iodide to the phosphonium salt. The aldehyde ester was prepared starting with the coupling of 7‐bromoheptanoic acid and 3‐butynol with lithium amide in liquid ammonia. The hydroxyalkynoic acid obtained was converted to the methyl ester and the hydroxy group was converted to the tetrahydropyranyloxy group. Subsequent deuteration of the methyl 11‐(2‐tetrahydropyranyloxy)‐8‐undecynoate with deuterium gas andtris‐(triphenylphosphine)chlorohodium gave the corresponding tetradeuterated product. The tetrahydropyranyl group was removed and the methyl 11‐hydroxy‐undecanoate‐8,8,9,9‐d4 was oxidized to the aldehyde ester with pyridinium chlorochromate. Methyl 8,11,14,17‐eicosatetraenoate‐8,9‐d2 was obtained by a similar sequence of reactions. The methyl 11‐oxo‐8‐undecenoate‐8,9‐d2 required for the Wittig coupling was obtained by Lindlar deuteration of the protected alkynoic ester to methyl 11‐(2‐tetrahydropyranyloxy)‐8‐undecenoate‐8,9d2. The unsaturated hydroxy ester was oxidized to the aldehyde ester by periodinane with negligible isomerization. The allcis isomers were isolated by silver resin chromatography.
Reactions of dinitrogen pentoxide and nitrogen dioxide with 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine
Authors: Lai C. C. , Finlayson‐Pitts B. J. 
Published: November 2006

AbstractThe reactions of gaseous dinitrogen pentoxide (N2O5) and nitrogen dioxide (NO2) with 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) coated on the inside surface of a glass reaction cell were studied at 298 K. Unsaturated phosphatidylcholines are significant components of pulmonary surfactant in the alveolar region of the lung and hence serve as a simple model to examine reactions of pulmonary surfactant with these oxidant air pollutants. Using high‐performance liquid chromatography (HPLC), Fourier transform infrared and fast atom bombardment mass spectroscopy, the major products of reactions of POPC with N2O5 and NO2 were separated and identified. In the POPC‐N2O5 reaction using either air or helium as a buffer gas, the nitronitrate, vinyl nitro and allylic nitro derivatives, as well as a small amount of thetrans‐isomer of the starting material, were obtained. The nature of the products obtained from the POPC‐NO2 reaction depends on the concentration of NO2 as well as whether air is present. At low NO2 concentrations (PNO2/N2O4≤3.8 Torr) in air or in helium, thetrans‐isomer of POPC was formed almost exclusively. At higher NO2 concentrations (PNO2/N2O4≥20 Torr) in helium, the dinitro, vinyl nitro and nitro alcohol derivatives were formed. In the presence of air (or 24%18O2 in helium), a nitronitrate and a dinitronitrate were additional products. Mechanisms for the formation of the observed products and implications for the inhalation of oxides of nitrogen are discussed.
Determination of phospholipase D‐mediated hydrolysis of phosphatidylethanolamine
Authors: Kiss Zoltan 
Published: November 2006

AbstractWhile phospholipase D‐mediated hydrolysis of phosphatidylcholine is well documented, we have recently shown that phospholipase D‐mediated hydrolysis of phosphatidylethanolamine (PtdEtn) [Kiss, Z., and Anderson, W.B.,J. Biol. Chem. 264, 1483–1487 (1989);J. Biol. Chem. 265, 7345–7350 (1990)] is equally prominent. This made it necessary to define in detail the conditions required for the detection of agonist‐stimulated PtdEtn hydrolysis. Using the [14C]ethanolamine‐prelabeled rat‐1 fibroblast model and 12‐O‐tetradecanoylphorbor 13‐acetate (TPA) as a model compound with the known ability to stimulate phospholipase D, we demonstrated that optimal detection of TPA‐induced ethanolamine release requires i) fractionation of water‐soluble ethanolamine products; ii) addition of unlabeled ethanolamine to quench the phosphorylation of newly formed [14C]ethanolamine; and/or iii) prolonged preincubation of prelabeled cells in an isotope‐free medium before the addition of TPA. This preincubation step reduces the cellular content of unincorporated14C‐labeled ethanolamine metabolites and improves the signal‐to‐noise ratio.
Synthesis of a phosphatidyl derivative of vitamin E and its antioxidant activity in phospholipid bilayers
Authors: Koga Takuro , Nagao Akihiko , Terao Junji , Sawada Kohei , Mukai Kazuo 
Published: November 2006

AbstractA novel phospholipid containing a chromanol structure at its polar head group was synthesized from egg yolk phosphatidylcholine and 2,5,7,8‐tetramethyl‐6‐hydroxy‐2‐(hydroxyethyl)chroman by transphosphatidylation catalyzed by phospholipase D fromStreptomyces lydicus. The structure of the product synthesized was shown by spectral analysis to be 1,2‐diacyl‐sn‐glycero‐3‐phospho‐2′‐hydroxyethyl‐2′ 5′,7′,8′‐tetramethyl‐6′‐hydroxychroman. The phosphatidylchromanol (PCh) showed antioxidant activity against radical chain oxidation of methyl linoleate in solution in a manner similar to that ofd‐α‐tocopherol (α‐Toc) and 2,2,5,7,8‐pentamethyl‐6‐chromanol. However, PCh was less effective as a chain‐breaking antioxidant than was α‐Toc when unilamellar egg yolk phosphatidylcholine liposomes were exposed to either a water‐soluble or a lipid‐soluble radical initiator. It is likely that the phospholipid nature of PCh affects the location and the mobility of the chromanol moiety in the membrane bilayer resulting in a decrease in antioxidant activity. On the other hand, the antioxidant activity of PCh was little different from that of α‐Toc in unilamellar liposomes when exposed to a lipid‐soluble radical initiator in the presence of ascorbic acid. It appears that PCh in phospholipid bilayers can be regenerated by ascorbic acid in aqueous phase as can be α‐Toc. The new phospholipid, phosphatidylchromanol, should prove useful as a chain‐breaking antioxidant in phospholipid membranes.
Butylated hydroxyanisole inhibits tumor necrosis factor‐induced cytotoxicity and arachidonic acid release
Authors: Brekke Ole‐Lars , Espevik Terje , Bjerve Kristian S. 
Published: November 2006

AbstractThe mechanisms by which the antioxidant butylated hydroxyanisole (BHA) inhibits recombinant tumor necrosis factor alpha (rTNF‐α)‐induced cytotoxicity have been studied in WEHI 164 clone 13 (WEHI) and L929 fibrosarcoma cells. When BHA was added simultaneously with rTNF‐α, it completely inhibited rTNF‐α cytotoxicity in the WEHI and L929 cells. BHA also inhibited the toxicity when added 2 h after rTNF‐α in WEHI cells, suggesting that BHA inhibits some late intracellular event(s) in rTNF‐α cytotoxicity. Pretreating WEHI cells with BHA for 4 h did not decrease the binding of rTNF‐α to its receptors as measured using flow cytometry. BHA inhibited rTNF‐α toxicity in the presence of actinomycin D and cycloheximide, indicating that neither mRNA nor protein synthesis is necessary for the BHA effect. The antioxidant butylated hydroxytoluene (BHT) and indomethacin did not inhibit the rTNF‐α‐induced cytotoxicity nor the rTNF‐α‐induced release of [3H]arachidonic acid. By comparison, BHA completely inhibited the rTNF‐α‐induced release of arachidonic acid, suggesting that BHA somehow inhibits rTNF‐α‐induced activation of phospholipase(s). In WEHI cells, rTNF‐α increased the level of protein‐associated thiobarbituric acid reactive substances (TBARS) dose‐dependently. BHA, but not BHT, blocked rTNF‐α‐induced cytotoxicity and rTNF‐α‐induced accumulation of protein‐associated TBARS, suggesting that rTNF‐α cytotoxicity is correlated with protein‐associated TBARS. In conclusion, the results suggest that BHA blocks some post receptor event in rTNF‐α‐induced cytotoxicity, and that activation of phospholipase(s) coupled with the enzymatic formation of specific oxidized lipids could be a pivotal event in rTNF‐α‐induced cytotoxicity.
Mass determination of the fatty acids released from tannin‐stimulated rabbit alveolar macrophages
Authors: Ralston Nicholas V. C. , Rohrbach Michael S. 
Published: November 2006

AbstractPrevious studies with macrophages that had been prelabeled with [14C]arachidonic acid (20∶4) have shown that condensed tannin is a potent agonist for the release of arachidonic acid. However, it has not been demonstrated that the percentage release of [14C]20∶4 accurately reflects the metabolic activity of the endogenous 20∶4 pool. In order to measure the 20∶4 mass release relative to the total cellular 20∶4 pool, the free fatty acids of freshly isolated alveolar macrophages were derivatized with a fluorescent reagent, and then separated and quantified by high‐performance liquid chromatography. The amounts of esterified fatty acids were measured by gas chromatography of the methyl esters. Free fatty acid levels were compared to those of the total esterified plus unesterified fatty acids to determine the actual percentage released of each fatty acid. Tannin‐stimulated release of 20∶4 mass reflected that previously reported for the release of [14C]20∶4 label but at a slower rate and at a much lower percentage indicating that [14C]20∶4 had been incorporated into part of a more reactive pool. The specificity of the fatty acid release induced by tannin and β‐1,3‐glucan, a known agonist for 20∶4 release, was also examined. Both agonists promoted an increase in the levels of free 20∶4 and of other fatty acids. A comparison of the absolute increases of each of the fatty acids indicated that tannin caused a preferential increase in the mass of free 20∶4, whereas β‐1,3‐glucan evoked a selective increase in the mass of 16∶0.
Essential fatty acids alter the activity of manganese‐superoxide dismutase in rat heart
Authors: Phylactos Andreas C. , Harbige Laurence S. , Crawford Michael A. 
Published: November 2006

AbstractThe effects of oil‐derived dietary essential fatty acids on the activities of mitchondrial Mn‐SOD (manganese‐superoxide dismutase) and cytosolic cupric zinc‐superoxide dismutase (Cu/Zn‐SOD) were investigated in rat heart. A control group of rats was fed a stock diet for 29 d, and a second group was fed on a fat‐free diet. Three other groups were fed fat‐free diets that were supplemented with (i) borage oil, which is rich in linoleic (18∶2n−6) and γ‐linolenic (18∶3n−6) acids, (ii) fungal oil, which is rich in γ‐linolenic, but low in linoleic acid, or (iii) evening primrose oil, which is rich in linoleic acid and low in γ‐linolenic acid. An increase in the percentage composition of arachidonic acid (20∶4n−6) in both the choline and ethanolamine phospholipids, together with a decrease in linoleic acid in ethanolamine phospholipids, were found in heart membranes after feeding the rats with diets containing borage oil or fungal oil as compared to those fed the stock diet. The respective activities of Mn‐SOD in rats fed the borage or fungal oil diets were also significantly higher than in rats fed the stock diet alone. No change in cytosolic Cn/Zn‐SOD activity was observed. Dietary supply of linoleic acid‐rich evening primrose oil resulted in an increased proportion of choline phospholipid linoleic acid without any changes in arachidonic acid content or in the activity of Mn‐SOD. By contrast, a reduction in the activity of Mn‐SOD was detected in rats fed a fat‐free diet. These results show that the activity of heart mitochondrial Mn‐SOD is influenced by dietary essential fatty acids, whereas the activity of cytosolic Cu/Zn‐SOD remained unaffected.
Interactions between medium‐chain and long‐chain triacylglycerols in lipid and energy metabolism in growing chicks
Authors: Mabayo Remedios T. , Furuse Mitsuhiro , Murai Atsushi , Okumura Jun‐ichi 
Published: November 2006

AbstractThe combined effects of dietary medium‐chain triacylglycerols (MCT) and long‐chain triacylglycerols (LCT) on lipid and energy utilization in chicks were investigated. Corn oil was used as the LCT source, and trioctanoin (8∶0) was used as the MCT source. The efficiency of dietary energy utilization (such as metabolizable energy values and fat and energy retention) decreased linearly as the level of MCT increased, but the efficiency of dietary protein utilization (protein retained per protein consumed) was not affected in a consistent manner. Fecal saturated and monounsaturated fatty acid composition was dependent on the dietary fatty acid composition, whereas fecal linoleic acid content was not. It is concluded that dietary MCT and LCT influence each other to some degree, with respect to protein and lipid metabolism in chicks. Moreover, in most cases, the nutritional characteristics of each triacylglycerol, including food efficiency and fat and energy retention, are independent of each other in growing chicks.