bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for specific ceramidase present in the intestinal contents of rats and humans
Authors: Duan Rui‐Dong , Cheng Yajun , Yang Liping , Ohlsson Lena , Nilsson Åke
Published: November 2006

A neutral ceramidase activity stimulated by bile salt was previously identified in the intestinal content. Recently, bile salt stimulated lipase (BSSL) was found to have ceramidase activity. It is unknown whether the ceramidase activity previously found is attributable to BSSL. To address this question, we compared the behaviors of high quaternary aminoethyl (HQ) anion exchange chromatography, the distributions, the stability, and the responses to lipase inhibitor between ceramidase and pancreatic BSSL. The proteins from whole small intestinal contents of humans and rats were precipitated by acetone and dissolved in 20 mM Tris buffer pH 8.2. These proteins had neutral ceramidase activity but not BSSL activity against p‐nitrophenyl acetate. When the proteins were subject to HQ chromatography, two peaks of ceramidase activity were identified, which had acid and neutral pH optima, respectively. Neither of them had BSSL activity against p‐nitrophenyl acetate. Western blot using BSSL antiserum failed to identify BSSL protein in the fractions, with high neutral ceramidase activity. In rat intestinal tract, pancreatic BSSL activity was high in the duodenum and declined rapidly in the small intestine, whereas neutral ceramidase activity was low in the duodenum and maintained a high level until the distal part of the small intestine. In addition, orlistat, the inhibitor of lipase, abolished human BSSL activity against p‐nitrophenyl acetate and slightly reduced its activity against ceramide but had no inhibitory effect on ceramidase activity isolated by HQ chromatography. In conclusion, we provide the evidence for a specific ceramidase other than pancreatic BSSL present in the intestinal content. The enzyme may play important roles in digestion of dietary sphingolipids.
Incubation of lipid emulsions with plasma lipoproteins modifies the fluidity of each particle
Authors: Chanson Nathalie F. , Lontie Jean‐François , Carpentier Yvon A. , Motta Claude
Published: November 2006

Lipid emulsions (LE) contain triglyceride (TG)‐rich particles (TGRP) and phospholipid‐rich particles (PLRP). Various lipid and protein exchanges take place during in vitro incubations of LE with lipoproteins. These composition changes affect physical properties of particles. The aim of this study was to determine the role of different LE particles and the effect of TG composition on physical modifications. Low density lipoproteins (LDL: 1.025<d<1.040 g/mL) or high density lipoproteins (HDL: 1.085<d<1.150 g/mL) were incubated with the following four LE or their TGRP or PLRP, which were manufactured with the same phospholipid emulsifier: long‐chain triglycerides (LCT): 100% soybean oil; medium‐chain triglycerides (MCT)/LCT (MCT/LCT, 5∶5, w/w); FO (100% fish oil); and MLF541 (MCT/LCT/FO, 5∶4∶1, by wt). After incubation, modified LE particles and lipoproteins were analyzed by fluorescence polarization. Observed physical modifications were significant in emulsion particles (ordering effect) but not in lipoporteins and also were significant for TG composition effect. Since intact emulsion contained a large excess of TGRP over PLRP, it is not surprising that intact emulsion had the same behavior as TGRP alone, and that PLRP had the same physical characteristics as lipoproteins. TG loss and cholesterol and protein acquisitions by emulsion particles rigidify their envelope. The two emulsions containing FO were less ordered after incubation. In conclusion, incubation of LE with lipoproteins changes physical properties of each kind of particle, and TG composition of the emulsion affects emulsion particle changes but has no effect on LDL and HDL. These order modifications induce more effective exchanges between LE particles and lipoproteins and modify their metabolism; HDL changes may increase the reverse cholesterol transport.
Comparative studies on individual isomeric 18∶1 acids in cow, goat, and ewe milk fats by low‐temperature high‐resolution capillary gas‐liquid chromatography
Authors: Precht Dietz , Molkentin Joachim , Destaillats Frédéric , Wolff Robert L.
Published: November 2006

The trans‐ as well as the cis‐18∶1 isomer profiles were established in cow, goat, and ewe cheese fats, with the assumption that these are representative of the corresponding milks. Argentation thin‐layer chromatography was combined with low‐temperature high‐resolution gas‐liquid chromatography on 100‐m highly polar capillary columns, thus adding precision to earlier data for these species. Despite differences in the absolute content of trans‐18∶1 isomers between species, the relative profiles were essentially similar. Except for the minor trans Δ6–Δ8 group, all trans‐18∶1 isomers with their ethylenic bonds between positions Δ4 and Δ16 (including the resolved critical pair Δ13/Δ14) were separated and quantitated individually. As expected, vaccenic (trans Δ9−18∶1) acid was the main isomer, accounting for as much as 37 to 50% of the total fraction. It was observed that the goat trans‐18∶1 isomer profile was usually rather close to that of cows in winter (barn feeding), whereas that of the ewe shows a seasonal dependence. The trans‐18∶1 profile of ewe milk fats from this study resembles that of cows in the transition period between winter and summer (pasture) feeding. Regarding the cis‐18∶1 acid fraction, two isomers (oleic and cis‐vaccenic acids) accounted for ca. 97% of that fraction for the three species, with the cis‐Δ12 isomer ranked third. The analytical procedure employed here appears a convenient alternative to oxidative‐based procedures (generally ozonolysis), taking less time and alleviating some draw‐backs of the latter procedure.
Enrichment of eggs with n−3 polyunsaturated fatty acids: Effects of vitamin E supplementation
Authors: Grune Tilman , Krämer Klaus , Hoppe Peter P. , Siems Werner
Published: November 2006

Eggs enriched with n−3 polyunsaturated fatty acids (PUFA) could contribute to dietary intake of these healthful fatty acids (FA). Because n−3 PUFA are highly susceptible to peroxidation, a first part of the study with Leghorn laying hens was carried out to investigate the influence of different levels of fish oil (0, 0.7, 1.4, 2.8, or 5.6%, respectively) in the diet on n−3 PUFA, cholesterol, vitamin E, and lipid peroxidation product contents in eggs. Addition of fish oil to a complete diet based on wheat, rye, tapioca, and soybean constituents containing 11 IU vitamin E/kg resulted in increased n−3 PUFA content in egg yolk, mainly due to accumulation of docosahexaenoic acid. Cholesterol was not altered up to 2.8% fish oil in the diet. The vitamin E content of the yolk was insufficient for the protection of PUFA from peroxidation. Addition of up to 2.8% fish oil to laying hen diets increased the n−3 PUFA content of yolks with a concomitant imbalance between vitamin E and PUFA, leading to increased levels of cytotoxic aldehydic lipid peroxidation products such as malondialdehyde (MDA). In a second part of the studies, the balance between vitamin E, PUFA, and lipid peroxidation was analyzed during the period of storage of n−3 PUFA‐enriched eggs produced after feeding the laying hens with 1.5% fish oil diets with different concentrations of vitamin E (0, 5, 10, 20, 40, 80, 160 IU/kg). Storage of eggs resulted in a marked loss of vitamin E in yolk. In stored eggs, the cytotoxic lipid peroxidation products MDA, 4‐hydroxynonenal, and 4‐hydroxyhexenal were reduced in response to vitamin E supplementation. To prevent the increase of cytotoxic aldehydic lipid peroxidation during production and storage of n−3 PUFA‐enriched eggs, a high vitamin E supplementation with at least 80 IU vitamin E/kg is needed.
Diferuloylputrescine and p‐coumaroyl‐feruloylputrescine, abundant polyamine conjugates in lipid extracts of maize kernels
Authors: Moreau Robert A. , Nuñez Alberto , Singh Vijay
Published: November 2006

Extraction of corn bran or corn fiber with polar solvents such as methylene chloride, ethanol or chloroform/methanol yielded common lipids and two unknown high‐performance liquid chromatography (HPLC) peaks, each with an ultraviolet absorbance maximum at 320 nm. HPLC‐mass spectrometry revealed that the unknowns were diferuloylputrescine (DFP) and p‐coumaroyl‐feruloylputrescine (CFP). When compared to extracts of corn fiber (a pericarp‐enriched fraction from the wet milling of corn), comparable extracts of corn bran (a pericarp‐ enriched fraction from the dry milling of corn) yielded three‐ to eightfold higher levels of DFP and CFP. Extraction of corn bran or fiber with an accelerated solvent extractor revealed that elevated temperatures greatly enhanced the extraction of DFP and CFP by methylene chloride and ethanol. “Corn bran oil,” prepared by extraction of corn bran with hot methylene chloride, contained 14 wt% DFP and 3 wt% CFP. However, when hexane was used as a solvent, accelerated solvent extraction of the corn bran or fiber did not extract any DFP or CFP. Extraction of wheat bran or psyllium hulls with hot methylene chloride did not yield any detectable DFP or CFP. Because it has been suggested that polyamine conjugates such as DFP and CFP may function as natural pesticides, a rapid method was developed to purify them so that their biological activity could be evaluated.
Characterization of lipoxygenase oxidation products by high‐performance liquid chromatography with electron impact‐mass spectrometric detection
Authors: Nuñez Alberto , Foglia Thomas A. , Piazza George J.
Published: November 2006

Lipoxygenase (LOX) is an enzyme that oxygenates polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. For example LOX found in plants produce the corresponding 13‐ and 9‐hydroperoxide derivatives of linoleic acid (13‐HPOD and 9‐HPOD). Identification of the HPOD products is usually accomplished by using gas chromatography with mass spectrometric (MS) detection, which requires extensive derivatization of the thermally unstable hydroperoxy group. Here we report a high‐performance liquid chromatographic method in combination with electron impact (EI)‐MS detection that separates and characterizes the HPOD isomers generated by soybean LOX type I oxygenation of linoleic (LA) and linolenic acids as well as HPOD products produced by photosensitized oxidation of LA. The method does not required derivatization of the hydroxyperoxide group, and location of its position can be determined by the EI‐MS fragmentation pattern. The method has been used for the analysis of HPOD produced by action of partially purified LOX from the micro‐alga Chlorella pyrenoidosa on LA. The study suggests the presence of two LOX isozymes in the micro‐alga that oxygenate LA to its 13‐HPOD and 9‐HPOD derivatives. Moreover, the 9‐LOX isozyme under anaerobic conditions cleaves 13‐HPOD to 13‐oxo‐tridecadienoic acid and pentane but does not cleave 9‐HPOD.
Mixed‐chain phospholipids: Structures and chain‐melting behavior
Authors: Huang Ching‐hsien
Published: November 2006

It has long been established that diacyl phospholipids isolated from animal cell membranes are predominantly of a mixed‐chain variety, meaning that the sn‐1 and sn‐2 acyl chains are saturated and unsaturated acyl chains, respectively. In general, monoenoic and dienoic acids are found in the sn‐2 acyl chain of phosphatidylcholine (PtdCho), whereas polyenoic acids are in phosphatidylethanolamine (PtdEth). These unsaturated chains contain only cis‐double bonds, which are always methylene‐interrupted. In recent years, the structures and the chain‐melting behavior of mixed‐chain PtdCho and PtdEth have been systematically studied in this laboratory. Specifically, we have examined the effects of chain unsaturation of the sn‐2 acyl chain on the phase transition temperature (Tm) of many PtdCho and PtdEth by high‐resolution differential scanning calorimetry (DSC). The Tm values, for instance, obtained from all‐unsaturated mixed‐chain PtdEth derived from a common precursor can be grouped together according to their chemical formula to form a Tm‐diagram. Hence, all the Tm values can be compared simply, systematically, and simultaneously using the Tm‐diagram. In addition, the energy‐minimized structures of mixed‐chain phospholipids containing different numbers/positions of methylene‐interruped cis‐double bonds have been simulated by molecular mechanics calculations (MM). In this review, the results of our MM and DSC studies carried out with various mixed‐chain phospholipids are summarized. In addition, we emphasize that the combined approach of MM and DSC yields unique uniformation that can correlate the various Tm‐profiles seen in the Tm‐diagram with the structural variation of mixed‐chain lipids as caused by the introduction of different numbers/positions of methylene‐interrupted cis‐double bonds.
Inhibitory effect of conjugated linoleic acid on linoleic acid elongation in transformed yeast with human elongase
Authors: Chuang Lu‐Te , Leonard Amanda E. , Liu Jim‐Wen , Mukerji Pradip , Bray Tammy M. , Huang Yung‐Sheng
Published: November 2006

Conjugated linoleic acid (CLA; 18∶2) refers to a group of positional and geometric isomers derived from linoleic acid (LA; Δ9, 12–18∶2). Using a growing baker's yeast (Saccharomyces cerevisiae) transformed with human elongase gene, we examined the inhibitory effect of CLA at various concentrations (10, 25, 50, and 100 μM) on elongation of LA (25 μM) to eicosadienoic acid (EDA; Δ11,14–20∶2). Among four available individual CLA isomers, only c9,t11‐ and t10,c12‐isomers inhibited elongation of LA to EDA. The extent of inhibition (ranging from 20 to 60%) was related to the concentration of CLA added to the medium. In the meantime, only these two isomers, when added at 50 μM to the media, were elongated to conjugated EDA (c11,t13‐ and t12,c14–20∶2) by the same recombinant elongase at the rate of 28 and 24%, respectively. The inhibitory effect of CLA on LA elongation is possibly due to competition between CLA isomers and LA for the recombinant elongase. Thus, results from this study and a previous study suggest that the biological effect of CLA is exerted through its inhibitory effect on Δ6‐desaturation as well as elongation of LA which results in a decrease in long‐chain n−6 fatty acids and consequently the eicosanoid synthesis.
A unique antioxidant activity of phosphatidylserine on iron‐induced lipid peroxidation of phospholipid bilayers
Authors: Dacaranhe Clemente Dique , Terao Junji
Published: November 2006

The relationship between the antioxidant effect of acidic phospholipids, phosphatidic acid (PA), phosphatidylglycerol (PG) and phosphatidylserine (PS), on iron‐induced lipid peroxidation of phospholipid bilayers and their abilities to bind iron ion was examined in egg yolk phosphatidylcholine large unilamellar vesicles (EYPC LUV). The effect of each acidic phospholipid added to the vesicles at 10 mol% was assessed by measuring phosphatidylcholine hydroperoxides (PC‐OOH) and thiobarbituric acid‐reactive substances. The addition of dipalmitoyl PS (DPPS) showed a significant inhibitory effect, although the other two acidic phospholipids, dipalmitoyl PA (DPPA) and dipalmitoyl PC (DPPG), did not exert the inhibition. Neither dipalmitoyl PC (DPPC) nor dipalmitoyl phophatidylethanolamine (DPPE) showed any remarkable inhibition on this system. None of the tested phospholipids affected the lipid peroxidation rate remarkably when the vesicles were exposed to a water‐soluble radical generator. The iron‐binding ability of each phospholipid was estimated on the basis of the amounts of iron recovered in the chloroform/methanol phase after separation of the vesicle solution to water/methanol and chloroform/methanol phases. EYPC LUV containing DPPS, DPPA, and DPPG had higher amounts of bound iron than those containing DPPC and DPPE, indicating that these three acidic phospholipids possess an iron‐binding ability at a similar level. Nevertheless, only DPPS suppressed iron‐dependent decomposition of PC‐OOH significantly. Therefore, it is likely that these three acidic phospholipids possess a significant iron‐binding ability, although this ability per se does not warrant them antioxidative activities. The ability to suppress the iron‐dependent decomposition of PC‐OOH may explain the unique antioxidant activity of PS.
Antioxidative activity of 3,4‐dihydroxyphenylacetic acid and caffeic acid in rat plasma
Authors: Raneva Violeta , Shimasaki Hiroyuki , Ishida Yumi , Ueta Nobuo , Niki Etsuo
Published: November 2006

The purpose of the present paper is to study and compare in vitro the inhibitory effect of 3,4‐dihydroxyphenylacetic acid (DOPAC) and caffeic acid (CA) on lipid peroxidation in rat plasma. Rat plasma was oxidized at 37°C by the radical initiators 2,2′‐azobis(2‐amidinopropane) dihydrochloride (AAPH) or 2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile) (MeO‐AMVN). The consumption of endogenous α‐tocopherol (α‐TOH) and the accumulation of conjugated diene hydroperoxides were measured by high‐performance liquid chromatography and by ultraviolet spectroscopy, respectively. α‐TOH was consumed at the same rate in the presence of 20 mM AAPH or 2 mM MeO‐AMVN. DOPAC and CA suppressed the α‐TOH consumption in a dose‐dependent manner. A concentration of 50 μM of both phenolic acids was sufficient to induce a lag phase and to delay the rate of α‐TOH consumption. The effect was more pronounced in rat plasma oxidation by AAPH than by MeO‐AMVN. CA spared vitamin E more effectively than DOPAC in both oxidations. DOPAC and CA suppressed the formation of conjugated diene hydroperoxides. DOPAC and CA at concentration 50 μM suppressed α‐TOH consumption during oxidation of soybean phosphatidylcholine (2.8 mM) multilamellar vesicles containing 15 μM α‐TOH, in which the lipophilic initiator 2,2′‐azobis (2,4‐dimethylvaleronitrile) (6 mM) was incorporated. In conclusion, we demonstrated that DOPAC and CA in micromolar concentrations have antioxidant activity in rat plasma, a medium very close to the conditions in vivo, suggesting that supplementation with the phenolic acids will provide significant antioxidant protection.
Postprandial triglyceride‐rich lipoprotein metabolism and insulin sensitivity in nonalcoholic steatohepatitis patients
Authors: Cassader Maurizio , Gambino Roberto , Musso Giovanni , Depetris Nadia , Mecca Fabio , Cavallo‐Perin Paolo , Pacini Giovanni , Rizzetto Mario , Pagano Gianfranco
Published: November 2006

Nonalcoholic steatohepatitis (NASH) is a syndrome frequently associated with obesity, diabetes mellitus, and dyslipidemia. Increased fasting insulinemia and blood glucose levels may trigger a reduced catabolism of lipoproteins rich in triglycerides by lipoprotein lipase (LPL) and an increase in their fasting and postprandial levels. An association between postprandial lipemia and coronary heart disease has been observed, and many studies now support this concept. The most important result of our study is the increase in triglyceride‐rich lipoproteins response after a fat load in NASH patients, the increase of incremental area under the postprandial curve, and the duration of the hypertriglyceridemic peaks. The persisting postprandial plasma triglyceride elevation in NASH patients was mostly due to the elevated plasma level of large triglyceride‐rich particles. These data are coupled with lower plasma HDL2‐cholesterol levels. As for lipoprotein analyses, the number of apolipoprotein B100 (ApoB100) particles is not significantly different between the two groups, and the higher content of triglycerides in NASH very low density lipoproteins (VLDL) increases the triglyceride‐to‐ApoB ratio and the particle size. A decreased enzymatic activity of LPL or a defective assembly and secretion of VLDL from hepatocytes due to a moderate reduction in microsomal triglyceride transfer protein could be involved in the overloading of VLDL. Moreover, the undetectable levels of ApoB48 in triglyceride‐rich lipoproteins fraction A could be related to the synthesis of smaller and denser chylomicrons. NASH patients not only are insulin resistant but also tend to present alterations in fatty meal delivery, suggesting that an increase in fasting plasma insulin and glucose, with insulin resistance, joins with depressed metabolism of triglyceride‐rich lipoproteins. An increase in postprandial triglyceride levels with production of large VLDL suggests an atherogenic behavior of lipid metabolism, in accordance with the high prevalence of the metabolic syndrome in NASH patients. This paper suggests that a fat load may be useful in early detection of atherogenic risk in the presence of otherwise normal fasting plasma lipids.
Arachidyl amido cholanoic acid (aramchol) is a cholesterol solubilizer and prevents the formation of cholesterol gallstones in inbred mice
Authors: Gilat Tuvia , Leikin‐Frenkel Alicia , Goldiner Ilana , Laufer Hava , Halpern Zamir , Konikoff Fred M.
Published: November 2006

We have recently synthesized fatty acid bile acid conjugates (FABAC) that were able to reduce and retard cholesterol crystallization in model and human biles. When given orally, they prevented the formation of cholesterol crystals in the bile of hamsters. The aim of the present study was to determine whether the FABAC are cholesterol solubilizers, whether they can dissolve pre‐existing crystals, whether they can prevent the formation of cholesterol gallstones, and to investigate the optimal type of bond between the fatty acid and bile acid. The presence of cholesterol crystals was determined by light microscopy, and the total crystal mass of precipitated crystals was measured by chemical means. Inbred (C57J/L) mice on a lithogenic diet were used to evaluate cholesterol crystal formation, dissolution, and gallstone formation in vivo. Arachidyl amido cholanoic acid (Aramchol) was the FABAC used in the present experiments. At equimolar amounts, the cholesterol‐solubilizing capacity of Aramchol was higher than that of taurocholate and similar to that of phosphatidylcholine. The addition of Aramchol dissolved approximately 50% of preexisting crystals in model bile solutions. The same phenomenon was demonstrated in human bile ex vivo, with a dose‐response effect. All inbred mice developed cholesterol crystals in bile after 10–14 d on the lithogenic diet. Thereafter, supplementation of the diet with Aramchol progressively reduced the proportion of mice with crystals to 25% after 28 d. On the lithogenic diet, 100% of inbred mice developed cholesterol gallstones in the gallbladder by day 21. None of the mice whose diet was supplemented with 0.5 mg or 1.0 mg of Aramchol/d developed stones or crystals. FABAC are a new class of molecules that are cholesterol solubilizers and which are able to dissolve cholesterol crystals in bile. Upon oral administration, they dissolve pre‐existing cholesterol crystals and prevent the formation of gallstones in gallstone‐susceptible mice.
Alterations in fatty acid composition of tissue phospholipids in the developing retinal dystrophic rat
Authors: Alessandri J. M. , Goustard‐Langelier B.
Published: November 2006

Alterations in lipid composition occur in the retinal pigment epithelium and photoreceptor cells of the Royal College of Surgeons (RCS) dystrophic rat, a model for inherited retinal degeneration. With respect to lipid composition of nonretinal tissues, the developmental timing of lipid alterations and the incidence of dystrophy are unknown. We determined the fatty acid composition in choline phosphoglycerides (ChoGpl) and ethanolamine phosphoglycerides (EtnGpl) in the brain, liver, and retina from dystrophic RCS rats and from their nondystrophic congenics (controls) at the ages of 3 and 6 wk. At 3 wk, the fatty acid compositions were specific to individual phospholipid classes without any difference between dystrophic and nondystrophic tissues. In plasma phospholipids, there was an age‐related increase in the relative contents of monounsaturated and n‐3 polyunsaturated fatty acids, with only minor differences between dystrophic and nondystrophic rats. At 6 wk, the fatty acid compositions in ChoGpl and EtnGpl from dystrophic brain and retina were significantly different from those of nondystrophics. The effect of strain on developmental changes in brain fatty acid composition was significant for 18∶0 and 22∶6n−3 in EtnGpl and for 16∶0, 18∶0, 18∶1n−9, and 20∶4n−6 in ChoGpl. The brain ChoGpl fatty acid composition in nondystrophic rats was similar at 6 wk to that of normal rats, and there were almost no postweaning changes in the dystrophics. In retinal phospholipids, the effect of dystrophy was to increase the 20∶4n−6 content in EtnGpl and to decrease 22∶6n−3 in ChoGpl. The 18∶2n−6 and 22∶6n−3 contents in dystrophic liver ChoGpl were also significantly affected, while no difference was observed in the EtnGpl fraction. The dystrophy affected the phospholipid fatty acid developmental changes in a tissue‐ and class‐specific manner. Fatty acid metabolism could be selectively altered in neural and nonneural tissues of developing dystrophic RCS rats.
Biosynthesis and tissue deposition of docosahexaenoic acid (22∶6n−3) in rainbow trout (Oncorhynchus mykiss)
Authors: Bell M. V. , Dick J. R. , Porter A. E. A.
Published: November 2006

Rainbow trout (Oncorhynchus mykiss) weighing ca. 5 g and previously acclimated for 8 wk on a diet comprising vegetable oil (11%), fish meal (5%), and casein (48%) as the major constituents were fed a pulse of diet containing deuterated (D5) (17,17,18,18,18)‐18∶3n−3 ethyl ester. The synthesis and tissue distribution of D5‐22∶6n−3 was determined 3,7,14, 24, and 35 d after the pulse. The whole‐body accumulation of D5‐22∶6n−3 was linear over the first 7 d, corresponding to a rate of 0.54±0.12 μg D5‐22∶6n−3/g fish/mg D5‐18∶3n−3 eaten/d. Maximal accretion of D5‐22∶6n−3 was 4.3±1.2 μg/g fish/mg of D5‐18∶3n−3 eaten after 14 d. The amount of D5‐22∶6n−3 peaked in liver at day 7, in brain and eyes at day 24, and plateaued after day 14 in visceral and eye socket adipose tissue and in the whole fish. The majority of D5‐22∶6n−3 was found in the carcass (remaining tissues minus the above tissues analyzed separately) at all times. On a per milligram lipid basis, liver and eyes had the highest concentration of D5‐22∶6n−3. The experimental diet also contained 21∶4n−6 ethyl ester as a marker to estimate the amount of food eaten by individual fish. From such estimates it was calculated that the great majority of the D5‐tracer was catabolized, with the combined recovery of D5‐18∶3n−3 plus D5‐22∶6n−3 being 2.6%. The recovery of 21∶4n−6 was 57.6%. The concentration of 22∶6n−3 in the fish decreased during the 13‐wk period, and the amount of 22∶6n−3 synthesized from 18∶3n−3 was only about 5% of that obtained directly from the fish meal in the diet.
An octaethylene glycol monododecyl ether‐based mixed micellar assay for determining the lipid acyl hydrolase activity of patatin
Authors: Jimenez Mercedes , Escribano Josefa , Pérez‐Gilabert Manuela , Chazarra Soledad , Cabanes Juana , García‐Carmona Francisco
Published: November 2006

Patatin was extracted from potato tubers (Solanum tuberosum L. cv. Spunta) and purified to homogeneity by ammonium sulfate salt fractionation and one sole chromatographic step. A spectrophotometric mixed micellar assay for patatin lipid acyl hydrolase (LAH) activity was designed with the detergent octaethylene glycol monododecyl ether (C12E8). Patatin LAH used p‐nitrophenyl butyrate (PNP‐butyrate) as substrate when solubilized in (C12E8) micelles. In the mixed micellar system, patatin LAH responds to the PNP‐butyrate surface concentration expressed as mol% (=[PNP‐butyrate]·100/([detergent]‐critical micellar concentration)) and not to the molarity of PNP‐butyrate. The kinetic parameters were determinined; Vmax was independent of the mixed micelle concentration, as was Km, when expressed as mol%. However, Km was dependent on C12E8 concentration when expressed in molar concentration. C12E8/PNP‐butyrate proved to be a reliable system for assaying patatin LAH activity and is superior to the commonly used Triton X‐100 and SDS methods. It permits investigation of the substrate requirements of patatin LAH activity because the concentration‐independent Km can be determined both in mol% and as the absolute number of substrate molecules per micelle. In addition, the detergent did not affect the enzyme activity.
Transforming growth factor beta in human milk does not change in response to modest intakes of docosahexaenoic acid
Authors: Hawkes J. S. , Bryan D‐L. , Neumann M. A. , Makrides M. , Gibson R. A.
Published: November 2006

Long‐chain polyunsaturated fatty acids have been associated with aspects of immune regulation including cytokine production. The purpose of this study was to investigate the effect of maternal dietary supplementation with tuna oil, rich in docosahexaenoic acid (DHA), on the concentration of transforming growth factor beta 1 (TGFβ1) and TGFβ2 in breast milk. In this randomized, dietary intervention trial, mothers of term infants consumed a daily supplement of 2000 mg oil containing either placebo (n=40), 300 mg DHA (n=40), or 600 mg DHA (n=40). The DHA increase in milk and plasma was proportional to dietary DHA. There was no relationship between milk DHA status and TGFβ1 and TGFβ2 levels.
Influence of dietary supplementation with long‐chain n−3 or n−6 polyunsaturated fatty acids on blood inflammatory cell populations and functions and on plasma soluble adhesion molecules in healthy adults
Authors: Thies F. , Miles E. A. , Nebe‐von‐Caron G. , Powell J. R. , Hurst T. L. , Newsholme E. A. , Calder P. C.
Published: November 2006

Greatly increasing the amounts of flaxseed oil [rich in α‐linolenic acid (ALNA)] or fish oil (FO); [rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in the diet can decrease inflammatory cell functions and so might impair host defense. The objective of this study was to determine the effect of dietary supplementation with moderate levels of ALNA, γ‐linolenic acid (GLA), arachidonic acid (ARA), DHA, or FO on inflammatory cell numbers and functions and on circulating levels of soluble adhesion molecules. Healthy subjects aged 55 to 75 yr consumed nine capsules per day for 12 wk. The capsules contained placebo oil (an 80∶20 mix of palm and sunflowerseed oils) or blends of placebo oil with oils rich in ALNA, GLA, ARA, or DHA or FO. Subjects in these groups consumed 2 g ALNA; approximately 700 mg GLA, ARA, or DHA; or 1 g EPA plus DHA (720 mg EPA+280 mg DHA) daily from the capsules. Total fat intake from the capsules was 4 g per day. None of the treatments affected inflammatory cell numbers in the bloodstream; neutrophil and monocyte phagocytosis or respiratory burst in response to E. coli; production of tumor necrosis factor‐α, interleukin‐1β, and interleukin‐6 in response to bacterial lipopolysaccharide; or plasma concentrations of soluble intercellular adhesion molecule‐1. In contrast, the ALNA and FO treatments decreased the plasma concentrations of soluble vascular cell adhesion molecule‐1 (16 and 28% decrease, respectively) and soluble E‐selectin (23 and 17% decrease, respectively). It is concluded that, in contrast to previous reports using higher amounts of these fatty acids, a moderate increase in consumption of long‐chain n−6 or n−3 polyunsaturated fatty acids does not significantly affect inflammatory cell numbers or neutrophil and monocyte responses in humans and so would not be expected to cause immune impairment. Furthermore, we conclude that moderate levels of ALNA and FO, which could be incorporated into the diet, can decrease some markers of endothelial activation and that this mechanism of action may contribute to the reported health benefits of n−3 fatty acids.
Effects of dietary virgin olive oil phenols on low density lipoprotein oxidation in hyperlipidemic patients
Authors: Masella Roberta , Giovannini Claudio , Varì Rosaria , Di Benedetto Roberta , Coni Ettore , Volpe Roberto , Fraone Nadia , Bucci Antonello
Published: November 2006

The aim of this study was to assess the effects of the dietary intake of extra virgin olive oil on the oxidative susceptibility of low density lipoproteins (LDL) isolated from the plasma of hyperlipidemic patients. Ten patients with combined hyperlipidemia (mean plasma cholesterol 281 mg/dL, triglycerides 283 mg/dL) consumed a low‐fat, low‐cholesterol diet, with olive oil (20 g/d) as the only added fat, with no drug or vitamin supplementation for 6 wk. Then they were asked to replace the olive oil they usually consumed with extra virgin olive oil for 4 wk. LDL were isolated at the beginning, and after the 4 wk of dietary treatment. LDL susceptibility to CuSO4‐mediated oxidation was evaluated by measuring the extent of lipid peroxidation. We also determined fatty acid composition and vitamin E in plasma and LDL and plasma phenolic content. Extra virgin olive oil intake did not affect fatty acid composition of LDL but significantly reduced the copper‐induced formation of LDL hydroperoxides and lipoperoxidation end products as well as the depletion of LDL linoleic and arachidonic acid. A significant increase in the lag phase of conjugated diene formation was observed after dietary treatment. These differences are statistically correlated with the increase in plasma phenolic content observed at the end of the treatment with extra virgin olive oil; they are not correlated with LDL fatty acid composition or vitamin E content, which both remained unmodified after the added fat change. This report suggests that the daily intake of extra virgin olive oil in hyperlipidemic patients could reduce the susceptibility of LDL to oxidation, not only because of its high monounsaturated fatty acid content but probably also because of the antioxidative activity of its phenolic compounds.
Production of docosahexaenoic acid by Crypthecodinium cohnii grown in a pH‐auxostat culture with acetic acid as principal carbon source
Authors: Ratledge Colin , Kanagachandran K. , Anderson Alistair J. , Grantham David J. , Stephenson Janet C.
Published: November 2006

Crypthecodinium cohnii, a marine alga used for the commercial production of docosahexaenoic acid (DHA), was cultivated in medium containing sodium acetate as principal carbon source; the pH was maintained at a constant value by addition of acetic acid, which also provided an additional carbon source in a controlled manner. The accumulation of lipid by C. cohnii in this pH‐auxostat culture was significantly greater than previously reported for batch cultures using glucose as principal carbon source. Of six strains tested in pH‐auxostat cultures, C. cohnii ATCC 30772 was the best, with the cells reaching 20 to 30 g dry weight per liter after 98 to 144 h and containing in excess of 40% (w/w) total lipid, with DHA representing approximately half of the total fatty acids in the triacylglycerol fraction. A productivity of 36 mg DHAL−1 h−1 was achieved during cultivation for 98 h using a 5% (vol/vol) inoculum, and DHA production was in excess of 3 g per liter of culture. Most of the DHA was present in neutral lipids.
Sphingophosphonolipids, phospholipids, and fatty acids from aegean jellyfish Aurelia aurita
Authors: Kariotoglou Dimitrios M. , Mastronicolis Sofia K.
Published: November 2006

The goal of this study is to elucidate and identify several sphingophosphonolipids from Aurelia aurita, an abundant but harmless Aegean jellyfish, in which they have not previously been described. Total lipids of A. aurita were 0.031–0.036% of fresh tissue, and the lipid phosphorus content was 1.3–1.7% of total lipids. Phosphonolipids were 21.7% of phospholipids and consisted of a major ceramide aminoethyl‐phosphonate (CAEP‐1; 18.3%), as well as three minor CAEP (II, III, IV) methyl analogs at 1.3, 1.1, and 1.0%, respectively. The remaining phospholipid composition was: phosphatidylcholine, 44.5%, including 36.2% glycerylethers; phosphatidylethanolamine, 18.6%, including 4.5% glycerylethers; cardiolipin, 5.6%; phosphatidylinositol, 2.6%; and lysophosphatidylcholine, 5.0%. In CAEP‐1; saturated fatty acids of 14–18 carbon chain length were 70.8% and were combined with 57.3% dihydroxy bases and 23.4% trihydroxy bases. The suite of the three minor CAFP methyl analogs were of the same lipid class based on the head group, but they separated into three different components because of their polarity as follows: CAEP‐II and CAEP‐III differentiation from the major CAEP‐I was mainly due to the increased fatty acid unsaturation and not to a different long‐chain base, but the CAEP‐IV differentiation from CAEP‐I, apart from fatty acid unsaturation, was due to the increased content of hydroxyl groups originated from both hydroxy fatty acids and trihydroxy long‐chain bases. Saturated fatty acids were predominant in total (76.7%), polar (83.0%), and neutral lipids (67.6%) of A. aurita. The major phospholipid components of A. aurita were comparable to those previously found in a related organism (Pelagia noctiluca), which can injure humans.
Separation and identification of phospholipid peroxidation products
Authors: Milne Ginger L. , Porter Ned A.
Published: November 2006

The molecular species in mixtures of phospholipid hydroperoxides are difficult to separate and identify by typical chromatographic and mass spectrometric techniques. As reported by Havrilla and coworkers, silver ion coordination ionspray mass spectrometry (CIS‐MS) has proven to be a powerful technique for the identification of mixtures of hydroperoxides. This ionization technique, which involves the formation of Ag+ adducts of the hydroperoxides, provides valuable, unambiguous structural information about the hydroperoxides. Herein, we report a method for the analysis and identification of phospholipid hydroperoxides using CIS‐MS. We also report an improved method for the separation of phospholipid hydroperoxides by reversed‐phase high‐performance liquid chromatography (RP‐HPLC), which, for the first time, separates some of the hydroperoxide isomers. CIS‐MS can be coupled with this RP‐HPLC method by the addition of AgBF4 to the mobile phase or to the HPLC effluent postcolumn, thus allowing powerful HPLC‐MS techniques to be used to identify complex mixtures of phospholipid hydroperoxides.
Plasma kinetics of a cholesterol‐rich emulsion in young, middle‐aged, and elderly subjects
Authors: Pinto Lígia B. , Wajngarten Mauricio , Silva Edson L. , Vinagre Carmen C. , Maranhão Raul C.
Published: November 2006

Low density lipoprotein (LDL) plasma concentration is increased in the elderly. In this group, the incidence of coronary artery disease (CAD) is greater and LDL remains an important risk factor for CAD development. In this study, the plasma kinetics of a cholesterol‐rich emulsion that binds to LDL receptors was studied in 10‐subject groups of the elderly (70±4 yr), middle‐aged (42±5 yr) and young (23±2 yr). All were normolipidemic, nonobese, nondiabetic subjects who did not have CAD. The emulsion was labeled with 14C‐cholesteryl oleate and injected intravenously into the subjects. Blood samples were drawn at regular intervals over 24 h to determine the plasma decay curve of the emulsion radioactive label and to estimate its plasma fractional clearance rate (FCR, in h−1). FCR of the emulsion label was smaller in elderly compared to young subjects (0.032±0.035 and 0.071±0.049 h−1, respectively; mean±SD, P<0.05). FCR of the middle‐aged subjects (0.050±0.071 h−1) was intermediate between the values of the elderly and young subjects, although not statistically different from them. A negative correlation was found between the emulsion FCR and subjects’ age (r=−0.47, P=0.008). We conclude that aging is accompanied by progressively diminished clearance of the emulsion cholesterol esters and, by analogy, of the native LDL.
Incorporation of α‐tocopherol in marine lipid‐based liposomes: in vitro and in vivo studies
Authors: Nacka Fabienne , Cansell Maud , Méléard Philippe , Combe Nicole
Published: November 2006

Liposomes made from a natural marine lipid extract and containing a high polyunsaturated n−3 fatty lipid ratio were envisaged as oral route vectors and a potential α‐tocopherol supplement. The behavior of vesicles obtained by simple filtration and of giant vesicles prepared by electroformation was investigated in gastrointestinal‐like conditions. The influence of α‐tocopherol incorporation into liposomes was studied on both physical and chemical membrane stability. Propanal, as an oxidation product of n−3 polyunsaturated fatty acids, was quantified by static headspace gas chromatography when α‐tocopherol incorporation into liposome ratios ranged from 0.01 to 12 mol%. Best oxidative stability was obtained for liposomes that contained 5 mol% α‐tocopherol. Compared to the other formulas, propanal formation was reduced, and time of the oxidation induction phase was longer. Moreover, α‐tocopherol induced both liposome structural modifications, evidenced by turbidity, and phospholipid chemical hydrolysis, quantified as the amount of lysophospholipids. This physicochemical liposome instability was even more pronounced in acid storage conditions, i.e., α‐tocopherol incorporation into liposome membranes accelerated the structural rearrangements and increased the rate of phospholipid hydrolysis. In particular, giant vesicles incubated at pH 1.5 underwent complex irreversible shape transformations including invaginations. In parallel, the absorption rate of α‐tocopherol was measured in lymph‐cannulated rats when α‐tocopherol was administrated, as liposome suspension or added to sardine oil, through a gastrostomy tube. α‐Tocopherol recovery in lymph was increased by almost threefold, following liposome administration. This may be related to phospholipids that should favor α‐tocopherol solubilization and to liposome instability in the case of a high amount of α‐tocopherol in the membranes. A need to correlate results obtained from in vitro liposome behavior with in vivo lipid absorption was demonstrated by this study.
Novel vitamin E derivative with 4‐substituted resorcinol moiety has both antioxidant and tyrosinase inhibitory properties
Authors: Shimizu Kuniyoshi , Kondo Ryuichiro , Sakai Kokki , Takeda Norio , Nagahata Tetsuji , Oniki Takayuki
Published: November 2006

A novel vitamin E derivative, (6″‐hydroxy‐2″,5″,7″,8″‐tetramethylchroman‐2″‐yl) methyl 3‐(2′,4′‐dihydroxyphenyl)propionate (TM4R), which has a chromanoxyl ring and 4‐substituted resorcinol moieties, was synthesized; and its inhibitory effects on tyrosinase, antioxidant ability, and lightening effect of ultraviolet B (UVB)‐induced hyperpigmentation were estimated. TM4R showed potent inhibitory activity on tyrosinase, which is the rate‐limiting enzyme in melanogenesis. The scavenging activities of TM4R on 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl radicals were found to be nearly the same as those of α‐tocopherol. Furthermore, an efficient lightening effect was observed following topical application of TM4R to UVB‐stimulated hyperpigmented dorsal skin of brownish guinea pigs. These results suggest that TM4R may be a candidate for an efficient whitening agent, possibly by inhibiting tyrosinase activity and biological reactions caused by reactive oxygen species.
Sterol biosynthesis by the arbuscular mycorrhizal fungus Glomus intraradices
Authors: Fontaine Joël , Grandmougin‐Ferjani Anne , Hartmann Marie‐Andrée , Sancholle Michel
Published: November 2006

Ri‐T‐DNA‐transformed carrot roots were used for investigating sterol metabolism by the arbuscular mycorrhizal (AM) fungus Glomus intraradices under three distinct experimental conditions: (i) a symbiotic stage (fungus still attached to the host roots); (ii) a detached stage (fungus physically separated from the roots); and (iii) a germinating stage (germinating spores). In all three stages, G. intraradices was found to contain a mixture of 24‐alkylated sterols, with 24‐methyl and 24‐ethyl cholesterol as the main compounds, but no ergosterol, the predominant sterol in most fungi. Feeding experiments with [1‐14C]sodium acetate were performed to check the ability of the fungus to synthesize sterols. Whatever the experimental conditions, G. intraradices was able to actively take up exogenous acetate and to incorporate it into sterols and their precursors. Our data provide first evidence for de novo sterol synthesis by an AM fungus.
A new trihydroxy fatty acid from the ascomycete, Chinese truffle Tuber indicum
Authors: Gao Jin‐Ming , Wang Chen‐Ying , Zhang An‐Ling , Liu Ji‐Kai
Published: November 2006

From the chloroform/methanol extract of the fruiting bodies of the ascomycete Chinese truffle Tuber indicum Cooke et Massee, a new trihydroxylated monounsaturated fatty acid (1) has been isolated. The structure of this new linoleic acid‐derived metabolite was established as 9,10,11‐trihydroxy‐(12Z)‐12‐octadecenoic acid by means of spectroscopic and chemical methods. The fatty acid composition of the chloroform‐soluble fraction of this fungus was analyzed by gas chromatography‐mass spectrometry. The content of the predominant unsaturated fatty acids (oleic and linoleic acids) is as high as 68%. The use of dimethyl disulfide adduct was effective in the determination of the position of the double bond, and the glycol oxidation fission reaction with sodium metaperiodate supported on silica gel was helpful in establishing the location of the trihydroxylic groups in the new fatty acid.
Lipids and endothelium‐dependent vasodilation—A review
Authors: Lind Lars
Published: November 2006

Studies using bothin vitroandin vivotechniques have repeatedly shown that endothelium‐dependent vasodilation (EDV) is impaired in different forms of experimental as well as human hypercholesterolemia. Clearly this impaired EDV can be reversed by lowering cholesterol levels by diet or medical therapy. Competitive blocking ofl‐arginine, changes in nitric oxide synthase acitivity, increased release of endothelin‐1, and inactivation of nitric oxide due to superoxide ions all contribute to the impairment in EDV during dyslipidemia. The oxidation of low density lipoprotein, with its compound lysophosphatidylcholine, plays a critical role in these events. However, data on the role of triglycerides and fat‐rich meals regarding EDV are not so consistent as data for cholesterol, although a view that the compositions of individual fatty acids and antioxidants are of major importance is emerging. Thus, this review shows that while impaired FDV is a general feature of hypercholesterolemia, the mechanisms involved and the therapeutic opportunities available still have to be investigated. Furthermore, discrepancies regarding the role of triglycerides and fat content in food may be explained by divergent effects of different fatty acids on the endothelium.