bluuebunny/crossref_metadata_2025 huggingface dataset:
The assembly of hepatic very low density lipoproteins: Evidence of a role for the Golgi apparatus
Authors: Valyi‐Nagy Klara , Harris Carla , Swift Larry L.
Published: November 2006

Previous studies from our laboratory have suggested that the assembly of lipoproteins by the liver is not completed in the rough endoplasmic reticulum but continues while the particles are en route to or within the Golgi apparatus. To investigate further the role of the Golgi apparatus in lipoprotein assembly, mice were injected with [3H]glycerol and killed 7.5 to 45 min after injection. Microsomes and Golgi apparatus‐rich fractions were isolated from the livers and separated into membrane and content fractions. TG within microsomal and Golgi membranes were labeled, rapidly reaching peak specific activity within 7.5 min of isotope injection. The specific activity of TG in microsomal membranes decreased to approximately 40% of peak values by 45 min, whereas the specific activity of TG in the Golgi membranes decreased to approximately 30% of peak values by 45 min. To determine whether the turnover of the Golgi membrane TG pool was dependent on microsomal TG transfer protein (MTP), mice were gavaged with an MTP inhibitor, and the labeling experiments were repeated. Inhibition of MTP attenuated the turnover of newly synthesized Golgi membrane TG by approximately 50% and the turnover of microsomal membrane TG by approximately 40%. Based on the rapid turnover of the Golgi membrane TG pool and the attenuation of the turnover of this pool by MTP inhibitor, we propose that lipid is transferred from the Golgi membrane to luminal lipoproteins in an MTP‐dependent manner. The results support our hypothesis that assembly of VLDL continues within the Golgi apparatus.
Comparison of the oxidizability of various glycerophospholipids in bilayers by the oxygen uptake method
Authors: Maeba Ryouta , Yusufu Youltuz , Shimasaki Hiroyuki , Ueta Nobuo
Published: November 2006

The aims of this study were twofold: develop a convenient and rapid procedure for assessing the oxidizability of small quantities of glycerophospholipids in bilayers by the oxygen uptake method, and determine and compare the oxidizability of various glycerophospholipids in bilayers. Our purpose was to educidate phospholipid oxidation characteristics in membranes. The quantitative autoxidation kinetics of dilinoleoyl phosphatidylcholine (DLPC) (18∶2/18∶2) was studied in large unilamellar vesicles (LUV) in aqueous dispersions with watersoluble initiator—2,2′‐azobis(2‐amidinopropane) dihydrochloride—and inhibitor 2‐carboxy‐2,5,7,8‐tetramethyl‐6‐chromanol. The kinetic data indicated a high efficiency of free radical production, resulting in shortening of measuring time; the very low kinetic chain length, particularly in the induction period, suggested the possibility of including large errors in thekinetics data. Nevertheless, the autoxidation of DLPC obeyed the classic rate law: Rp=kp[LH]Ri1/2/(2kt)1/2 (where Rp‐rate of oxygen consumption, kp=rate constant for chain propagation, [LH]‐substrate concentration; Ri1/2‐square root of rate of chain initiation, and 2kt=rate constant for chain termination) in a mixed bilayer system with saturated dimyristoyl PC (14∶0/14∶0), which provided precise and reproducible data. Therefore, the system was used to assess the relative oxidizability of each glycerophospholipid DLPC (18∶2/18∶2), dilinolenoyl PC (18∶3/18∶3), 1‐palmitoyl‐2‐linoleoyl PC (16∶0/18∶2), 1‐palmitoyl‐2‐arachidonoyl PC (16∶0/20∶4), 1‐palmitoyl‐2‐docosahexaenoyl PC (16∶0/22∶6), and dilinoleoyl PE (18∶2/18∶2) in bilayers. The results suggested that the oxidizability of glycerophospholipid in bilayers is substantially influenced by the number of intramolecular oxidizable acyl chains and the content of bis‐allylic hydrogen in a structured environment, and showed deviation of the rate law for autoxidation in PC and PE mixed LUV, which possibly was due to nonhomogeneous phospholipid distribution in vesicles.
31P NMR quantification and monophasic solvent purification of human and bovine lens phospholipids
Authors: Byrdwell William C. , Sato Hidetoshi , Schwarz Arne K. , Borchman Douglas , Yappert M. C. , Tang Daxin
Published: November 2006

Most lipid extraction procedures [Folch, J., Lees, M., and Sloane‐Stanley, G.H., (1957) A Simple Method for the Isolation and Purification of Total Lipids from Animal Tissues, J. Biol. Chem. 226, 497–509; Bligh, E.G., and Dyer, W.J. (1959) A Rapid Method of Total Lipid Extraction and Purification, Can. J. Biochem. Physiol. 37, 911–917] employ biphasic solvent mixtures designed to dissolve the lipids in an organic phase and remove impurities in an aqueous phase. However, when applying these protocols to biological matrices such as that of the ocular lens, the formation of an emulsion layer between the organic and aqueous phases causes poor reproducibility in extraction yields and gives only a small amount of the lipid‐containing chloroform phase. In this study, we quantified phospholipids at each step of the Folch et al. extraction protocol and compared the yield of human and bovine lens phospholipids obtained by the Folch‐based approach and a novel monophasic methanol extraction method designed to circumvent the problems associated with biphasic extraction protocols. A monophasic methanol extraction coupled with 31P NMR spectroscopy was found to be the simplest, quickest, and most effective method for quantifying the phospholipid content of the lens.
Simultaneous evaluation of HMG‐CoA reductase and cholesterol 7α‐hydroxylase activities by electrospray tandem MS
Authors: Ndong‐Akoume Marie‐Yvonne , Mignault Diane , Perwaiz Shahid , Plaa Gabriel L. , Yousef Ibrahim M.
Published: November 2006

Simultaneous evaluation of HMG‐CoA reductase and cholesterol 7α‐hydroxylase activities by electrospray tandem mass spectrometry (ES‐MS‐MS) was performed. The assay was based on the measurement of mevalonolactone (MVL) and 7α‐hydroxycholesterol (7α‐OHC) produced by the incubation of HMG‐CoA with hepatic microsomes in the presence of NADPH and glucose‐6‐phosphate dehydrogenase. Following extraction and purification using a cyanopropyl cartridge, MVL and 7α‐OHC were analyzed, without derivatization, by ES‐MS‐MS. The analysis was achieved in 5 min. Calibration curves were made for MVL and 7α‐OHC, and were linear from 0 to 100 μg. The recovery was >97%. The procedure was validated under similar calibration and recovery experiments, by measuring the above mentioned products as dimethylethylsilyl ether derivatives using the classical technique of GC‐MS. Data obtained by ES‐MS‐MS and GC‐MS showed a good correlation, with no significant differences. ES‐MS‐MS is a simple and reliable method for the evaluation of HMG‐CoA reductase and cholesterol 7α‐hydroxylase activities in liver microsomal preparations.
Distributions of hydroperoxide positional isomers generated by oxidation of 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphocholine in liposomes and in methanol solution
Authors: Wang Xing‐Hua , Ushio Hideki , Ohshima Toshiaki
Published: November 2006

The differences in distribution of geometric isomers of unsaturated PC hydroperoxides generated by free radical oxidation were compared, as corresponding hydroxy analogs, in heterogeneous liposomes and in a homogeneous methanol solution by using HPLC with UV detection due to the presence of conjugated dienes. Identification of fractionated peak components was carried out by GC‐MS. When the oxidation of 1‐palmitoyl‐2‐linoleoyl‐sn‐glycero‐3‐phosphocholine, PC(16∶0/18∶2), was initiated in liposomes by a hydrophilic azo radical initiator, and in a methanol solution by a hydrophobic azo radical initiator, there was no significant difference in the relative percentages of 1‐palmitoyl‐2‐(9‐hydroxy‐trans‐10,trans‐12‐octadecadienoyl)‐sn‐glycero‐3‐phosphocholine (9‐t,t‐OH PC) and 1‐palmitoyl‐2‐(13‐hydroxy‐trans‐9,trans‐11‐octadecadienoyl)‐sn‐glycero‐3‐phosphocholine (13‐t,t‐OH PC) between the PC oxidized in liposomes and in the methanol solution. For the oxidation of 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphocholine, PC(16∶0/20∶4), the relative percentage of 1‐palmitoyl‐2‐(5‐hydroxy‐trans‐6,cis‐8,11,14‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (5‐OH PC) was significantly higher (P<0.01) than that of 1‐palmitoyl‐2‐(15‐hydroxy‐cis‐5,8,11,trans‐13‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (15‐OH PC) in liposomes. For the homogeneous methanol solution of PC(16∶0/20∶4), the relative percentage of 5‐OH PC was close to that of 15‐OH PC. For the PC(16∶0/20∶4) oxidized in bulk with added pentamethylchromanol, the individual amount of 15‐OH PC, 1‐palmitoyl‐2‐(11‐hydroxy‐cis‐5,8trans‐12,cis‐14‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (11‐OH PC), 1‐palmitoyl‐2‐(12‐hydroxy‐cis‐5,8,trans‐10,cis‐14‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (12‐OH PC), 1‐palmitoyl‐2‐(8‐hydroxy‐cis‐5,trans‐9,cis‐11,14‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (8‐OH PC), 1‐palmitoyl‐2‐(9‐hydroxy‐cis‐5,trans‐7,cis‐11,14‐eicosatetraenoyl)‐sn‐glycero‐3‐phosphocholine (9‐OH PC), and 5‐OH PC were close to each other compared to the corresponding values in liposomes and in methanol solution. The results obtained by gel permeation chromatography of the PC liposomes containing hydrophilic 2,2′‐azobis‐2‐amidinopropane) dihydrochloride (AAPH) suggest that the AAPH added to the liposomes of PC(16∶0/20∶4) was partitioned into the water phase and out of the hydrophobic region of the fatty acyl moieties of the PC. These results confirm that the distance that exists in the bis‐allylic carbons of the unsaturated fatty acyl moieties of PC from the interface between the hydrophilic region of PC and the water phases played an important role in influencing hydrogen abstraction to form a symmetrical distribution of hydroperoxide isomers in both the heterogeneous liposomes and the homogeneous methanol solution.
New cerebrosides from the basidiomycete Cortinarius tenuipes
Authors: Tan Jian‐Wen , Dong Ze‐Jun , Liu Ji‐Kai
Published: November 2006

Five cerebrosides (1–5), including three new ones named cortenuamide A (1), cortenuamide B (2), and cortenuamide C (3), were isolated from the fruiting bodies of the basid‐iomycete Cortinarius tenuipes. The structures of those compounds were elucidated as (4E,8E)‐N‐d‐2′‐hydroxytetracosanoyl‐1‐O‐β‐d‐glycopyranosyl‐9‐methyl‐4,8‐sphingadienine (1), (4E,8E)‐N‐d‐2′‐hydroxytricosanoyl‐1‐O‐β‐d‐glycopyranosyl‐9‐methyl‐4,8 sphingadienine (2), (4E, 8E)‐N‐d‐2′‐hydroxydocosanoyl‐1‐O‐β‐d‐glycopyranosyl‐9‐methyl‐4,8‐sphingadienine (3), (4E, 8E)‐N‐d‐2′‐hydroxyoctadecanoyl‐1‐O‐β‐d‐glycopyranosyl‐9‐methyl‐4,8‐sphingadienine (4), and (4E, 8E)‐N‐d‐2′‐hydroxypalmitoyl‐1‐O‐β‐d‐glycopyranosyl‐9‐methyl‐4,8‐sphingadienine (5) by spectral and chemical methods.
Evaluation of apolipoprotein A‐I kinetics in rabbits in vivo using in situ and exogenous radioiodination methods
Authors: Zhang Bo , Shimoji Eiso , Tanaka Hiroaki , Saku Keijiro
Published: November 2006

The kinetics of in vivo clearance of apolipoprotein (apo) A‐I radioiodinated by the iodine monochloride (ICI) method of McFarlane [McFarlane, A.S. (1958) Efficient Trace‐Labelling of Proteins with Iodine, Nature 182, 53] as modified by Bilheimer and co‐workers [Bilheimer, D.W., Eisenberg, S., and Levy, R.I. (1972) The Metabolism of Very Low Density Lipoprotein Proteins. I. Preliminary in vitro and in vivo Observations, Biochim. Biophys. Acta 260, 212–221] and by using the IODO Beads Iodination Reagent were evaluated in rabbits. Both human apoA‐I and rabbit HDL radioiodinated by the IODO Beads Iodination Reagent were cleared faster from plasma of rabbits than those radiolabeled by the ICl method. However, the different radiolabeling procedures in the ICl method, i.e., apoA‐I radiolabeled either exogenously or in situ as a part of intact HDL, were not associated with a significant difference in the in vivo kinetics of apoA‐I in rabbits if apoA‐I was prepared by the guanidine HCl method and used fresh. 125I‐ApoA‐I subjected to delipidation and lyophilization was cleared only slightly faster from the plasma of rabbits than fresh 125I‐apoA‐I. We also found that apoA‐I separated by the guanidine HCl method and used fresh was cleared faster from the plasma of rabbits when it was injected as free apoA‐I without adding serum albumin or after in vitro incubation with rabbit HDL than when injected after reassociation with rabbit plasma. We conclude that the ICl method is a more appropriate radioiodination method for studying the in vivo kinetics of HDL than the IODO Beads Iodination Reagent and that the in vitro incubation conditions before injection are important factors that affect the in vivo kinetics of apo A‐I.
Functionalization of unactivated carbons in 3α,6‐ and 3α,24‐dihydroxy‐5β‐cholane derivatives by dimethyldioxirane
Authors: Iida Takashi , Shiraishi Keisuke , Ogawa Shoujiro , Goto Takaaki , Mano Nariyasu , Goto Junichi , Nambara Toshio
Published: November 2006

Direct remote functionalization of unactivated carbons by dimethyldioxirane (DMDO) was examined for 3α,6‐ and 3α,24‐dihydroxy‐5β‐cholane derivatives. DMDO oxidation of stereoisomeric methyl 3α,6‐diacetoxy‐5β‐cholanoates caused the direct, unexpected 14α‐ and 17α‐hydroxylations, in analogy with that of the 5α‐H analogs, regardless of the differences in stereochemical configuration of the A/B‐ring junction and of the acetoxyl groups at C‐3 and C‐6. On the other hand, the ester derivatives of 3α,24‐dihydroxy‐5β‐cholane with DMDO were transformed into the corresponding 5β‐, 14α‐, and 17α‐hydroxy compounds, whereas the ether derivatives yielded the 5β‐hydroxy, 3‐oxo, and C‐24 oxidized products, accompanied by their dehydrated ones.
Lipids and FA analysis of canine prostate tissue
Authors: Attar‐Bashi Nadia M. , Orzeszko Karyn , Slocombe Ronald F. , Sinclair Andrew J.
Published: November 2006

It is widely reported that an association exists between dietary fat intake and the incidence of prostate cancer in humans. To study this association, there is a need for an animal model where prostate carcinogenesis occurs spontaneously. The canine prostate is considered a suitable experimental model for prostate cancer in humans since it is morphologically similar to the human prostate and both humans and dogs have a predisposition to benign and malignant prostate disease. In this study, the FA and lipids profiles of the normal canine prostate tissue from nine dogs were examined. The total lipid content of the canine prostate tissue was 1.7±0.5% (wet weight). The lipid composition analysis using TLC‐FID showed that the two major lipid classes were phospholipids and TAG. Total FA, phospholipid, and TAG FA analysis showed that the major FA were palmitic acid (16∶0), stearic acid (18∶0), oleic acid (18∶1), linoleic acid (18∶2n−6), and arachidonic acid (20∶4n−6), The n−3 FA were present at <3% of total FA and included α‐linolenic acid (18∶3n−3) (in total and TAG tissue FA), EPA (20∶5n−3) (not in TAG), and DHA (22∶6n−3) (not in TAG). The n−3/n−6 ratio was 1∶11, 1∶13, and 1∶8 in total, phospholipid, and TAG FA, respectively. This study shows the canine prostate has a low level of n−3 FA and a low n−3/n−6 ratio. This is perhaps due to low n−3 content of the diet of the dogs. FA analysis of dogfoods available in Australia showed that the n−3 content in both supermarket and premium bran dogfoods was <3% (wet weight), and the n−3/n−6 ratio was low.
Impact of dietary n−3 FA deficiency on rat bone tissue FA composition
Authors: Li Yong , Greiner Rebecca S. , Salem Norman , Watkins Bruce A.
Published: November 2006

The effect of dietary n−3 FA deficiency on bone tissue FA composition was evaluated in growing rats. Two mixtures combining hydrogenated coconut oil with safflower oil served as the n−3‐deficient dietary treatments and provided two levels of linoleic acid (LA). The n−3 treatments were formulated with added α‐linolenic acid (LNA) from flaxseed oil (diet LNA) or LNA plus DHA, and both were balanced for LA. This study showed that bone is sensitive to changes in dietary n−3 FA and that DHA is more effective than LNA in maintaining DHA levels in these tissues.
Solubilization of carotenoids from carrot juice and spinach in lipid phases: II. Modeling the duodenal environment
Authors: Rich Gillian T. , Faulks Richard M. , Wickham Martin S. J. , Fillery‐Travis Annette
Published: November 2006

We have been investigating the factors determining the bioavailability of carotenoids from vegetables. The previous paper [Rich, G.T., Bailey, A.L., Faulks, R.M., Parker, M.L., Wickham, M.S.J., and Fillery‐Travis, A. (2003) Solubilization of Carotenoids from Carrot Juice and Spinach in Lipid Phases: I. Modeling the Gastric Lumen, Lipids 38, 933–945] modeled the gastric lumen and studied the solubilization pathway of carotenes and lutein from carrot juice and homogenized spinach to oil. Using the same vegetable preparations, we have extended our investigations to solubilization pathways potentially available in the duodenum and looked at the ease of solubilization of carotenes and lutein within simplified lipid micellar and oil phases present within the duodenum during digestion. Micellar solubility of raw spinach carotenoids was low and was enhanced by freezing, which involved a blanching step. The efficiency of solubilization of carotenoids in glycodeoxycholate micelles decreased in the order luteincarrot>luteinblanched‐frozen spinach>caroteneblanched‐frozen spinach>carotenecarrot. Frozen spinach carotenoids were less soluble in simple micelles of taurocholate than of glycodeoxycholate. The results comparing the solubility of the carotenoids in mixed micelles (bile salt with lecithin) with simple bile salt micelles are explained by the relative stability of the carotenoid in the organelle compared to that in the micelle. The latter is largely determined by the polarity of the micelle. Below their critical micelle concentration (CMC), bile salts inhibit transfer of carotenoids from tissue to a lipid oil phase. Above their CMC, the bile salts that solubilize a carotenoid can provide an additional route to the oil from the tissue for that carotenoid by virtue of the equilibrium between micellar phases and the interfacial pathway. Mixed micellar phases inhibit transfer of both carotenoids from the tissue to the oil phase, thereby minimizing this futile pathway.
Localization of clavulons, prostanoids with antitumor activity, within the Okinawan soft coral Clavularia viridis (alcyonacea, clavulariidae): Preparation of a high‐purity Symbiodinium faction using a protease and a detergent
Authors: Hashimoto Naoko , Fujiwara Shoko , Watanabe Kinzo , Iguchi Kazuo , Tsuzuki Mikio
Published: November 2006

To investigate the localization of clavulones (CV), prostanoids with antitumor activity, in the Okinawan soft coral Clavularia viridis, we developed a method for the isolation of Symbiodinium cells from the coral, i.e., treatment of a coral homogenate with a protease, pronase F, and a detergent, Nonidet P‐40. The conditions for the treatment were optimized by monitoring the morphology microscopically and the amount of chlorophyll in the Symbiodinium fraction (SymF) optically. To evaluate the purity of SymF and a Symbiodinium‐free coral fraction (CorF), we analyzed them for proteins and lipids using cultivated Symbiodinium as a reference. TLC of lipids revealed that SymF contained a greater amount of glycolipids, whereas CorF comprised mostly phospholipids. SDS‐PAGE of proteins in SymF and CorF revealed their distinct profiles. Thus, we could obtain each fraction with high purity; we reached the conclusion that CV and arachidonic acid, their possible precursor, are localized exclusively in the insoluble fraction of host coral cells.
Light‐scattering detection of phospholipids resolved by HPLC
Authors: Descalzo A. M. , Insani E. M. , Pensel N. A.
Published: November 2006

An improved method for the analysis of phospholipids by normal‐phase HPLC is described. Addition of methanol and acetonitrile to a gradient based on 2‐propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids (PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration curves were linear within the range of 5–40 μg with detection limits below 1 μg for PE and PC, and CV ranged from 0.6 to 9.6%. PL present in surfactant homogenates were separated by a solid‐phase extraction (SPE) procedure before HPLC analysis. This methodology gave a recovery of 95% and combined SPE‐HPLC and quantification of biological PL within a 30‐min run. The use of ELSD detection of the eluted compounds was precise, linear, and sensitive.
Serum and aortic levels of phytosterols in rabbits fed sitosterol or sitostanol ester preparations
Authors: Kritchevsky David , Tepper Shirley A. , Czarnecki Susanne K. , Wolfe Brian , Setchell Kenneth D. R.
Published: November 2006

Campesterol is present in all the phytosterol‐containing dietary hypocholesterolemic agents in current use. Campesterol is absorbed more efficiently than sitosterol, and the question of its possible atherogenicity has been raised. To test this possibility, rabbits were fed either a semipurified, cholesterol‐free diet that has been shown to be atherogenic for this species or the same diet augmented with 0.5 g of phytosterol‐rich diet preparations (spreads) containing either sitosterol or sitostanol. The diets contained 295 mg phytosterol per 100 g. After 60 d, serum cholesterol levels in the two phytosterol groups were 78±4 mg/dL (sitosterol) and 76±4 mg/dL (sitostanol), respectively. The serum cholesterol level of rabbits fed the control diet was 105±8 mg/dL. Serum campesterol (μg/mL) levels were higher than sitosterol or sitostanol levels in all groups. Aortic phytosterols were present in nanogram quantities compared to cholesterol, which was present in microgram quantities. The ratio of campesterol/sitosterol/sitostanol in the aortas was: control, 1.00∶0.43∶0.02; sitosterol, 1∶00∶0.32∶0.01; sitostanol, 1∶00∶0.34∶0.11. Aortic campesterol was present at 4% the concentration of aortic cholesterol, sitosterol at 1.4%, and sitostanol at 0.14%. Aortic lesions were not present in any of the animals.
Comparison of the effects of dietary sunflower oil and virgin olive oil on rat exocrine pancreatic secretion in vivo
Authors: Díaz Ricardo J. , Yago María D. , Martínez‐Victoria Emilio , Naranjo José A. , Martínez María A. , Mañas Mariano
Published: November 2006

The aim of this study was to investigate the functional consequences in vivo of adapting the rat exocrine pancreas to different dietary fats. Weanling rats were fed diets containing 10 wt% virgin olive oil or sunflower oil for 8 wk. We then examined resting and cholecystokinin‐octapeptide (CCK‐8)‐stimulated pancreatic secretion in the anesthetized animals. To confirm a direct influence of the type of fat upon the gland, the FA composition of pancreatic membranes as well as tissue protein and amylase content were determined in separate rats. The membrane FA profile was profoundly altered by the diets, reflecting the type of dietary fat given, although this was not paralleled by variations in the pancreatic content of protein or amylase. Nevertheless, dietary intake of oils evoked different effects on in vivo secretory activity. Resting flow rate and amylase output were significantly (P<0.05) enhanced by sunflower oil feeding. Time course changes in response to CCK‐8 infusion also showed a different pattern in each group. Secretion of fluid, protein, and amylase increased markedly in all animals, reaching a maximum within 20–40 min of infusion that was followed by a dramatic decline in both groups. In the sunflower oil group, this resulted in values reaching the resting level as soon as 60 min after CCK‐8 infusion was begun. However, after the initial decline, olive oil group values showed a prolonged plateau elevation above the baseline (P<0.05) that was maintained for at least the infusion time. In addition, a positive correlation between flow rate and both protein concentration and amylase activity existed in the olive oil group, but not in the sunflower oil group. The precise mechanism by which these effects are produced remains to be elucidated.
Hyperphagia modifies FA profiles of plasma phospholipids, plasma FFA, and adipose tissue TAG
Authors: Skuladottir Gudrun V. , Olason Pall I. , Jonsson Logi , Skarphedinsson Jon O. , Eriksdottir Vedis H. , Atlason Palmi Th. , Franzson Leifur , Schiöth Helgi B.
Published: November 2006

Hyperphagia was achieved by continuous intracerebroventricular infusion of a melanocortin receptor antagonist (HS024; Neosystem, Strasbourg, France) in rats. The effects of hyperphagia on FA composition and concentration of plasma phospholipids (PL), plasma FFA, and adipose tissue TAG were studied in rats for 8 d [short‐term hyperphagia (STH); n=8], or 28 d [longterm hyperphagia (LTH); n=9]. The control rats were treated with artificial cerebrospinal fluid for 8 d (n=8) or 28 d (n=10). The rats were fed the same regular diet. In STH rats the plasma PL and fasting plasma FFA contained higher concentrations of saturated FA (SFA) and monounsaturated FA (MUFA), and plasma FFA contained lower n−6 PUFA than in the control rats. In LTH rats the plasma PL contained higher concentrations of SFA, MUFA, and n−3 PUFA and higher proportions of 16∶1n−7 and 18∶1n−9 at the expense of 18∶2n−6 than in the control rats. In LTH rats the abundant dietary intake of 18∶2n−6 did not enrich 18∶2n−6 of the plasma PL or adipose tissue TAG. In LTH rats the fasting plasma FFA contained more than twofold higher concentrations of SFA and MUFA, and higher proportions of 16∶1n−7 and 18∶1n−9 at the expense of 18∶2n−6 than in the control rats. This animal obesity model shows that LTH affects the FA composition and concentration of plasma PL, plasma FFA, and adipose tissue TAG, a result consistent with changes associated with increased risk of various diseases in humans. These results also demonstrate that LTH alters the FA composition of plasma PL and adipose tissue TAG in a way that does not reflect the FA composition of dietary fat.
Trans‐18∶1 isomers in rat milk fat as effective biomarkers for the determination of individual isomeric trans‐18∶1 acids in the dams' diet
Authors: Wolff Robert L.
Published: November 2006

Female rats were fed a diet containing by weight 10% partially hydrogenated sunflower oil, 2% sunflower oil, and 1% rapeseed oil during gestation and lactation. The trans‐18∶1 isomer profile of the fat supplement was (in % of total trans 18∶1 acids in the fat supplement): Δ4, 0.5; Δ5, 1.0;Δ6–Δ8, 18∶0; Δ9 (elaidic), 13.5; Δ10, 22.2;Δ11 (vaccenic), 16.0; Δ12, 11.3; Δ13–Δ14, 12.8; Δ15, 2.5; and Δ16, 2.2 (total trans 18∶1 acids in the fat supplement: 40.6%). The cis 18∶1 isomer profile was (in % of total cis‐18∶1 isomers):Δ6, Δ8, 2.1; Δ9 (oleics), 70.9; Δ10, 6.1; Δ11, 8.3; Δ12, 4.0; Δ13, 2.8; Δ14, 4.6, and Δ15, 1.2 (total cis‐18∶1 acids in the fat supplement: 32.6%). Suckling rats from four litters were sacrificed at day 17 or 18 after birth, and their stomach content (milk) was analyzed. The trans‐18∶1 isomer profile of milk was (relative proportions, in % of total): Δ4, 0.3; Δ5, 1.1; Δ6–Δ8, 16.8; Δ9, 15.3; Δ10, 22.0; Δ11, 16.7; Δ12, 11.8; Δ13–14, 11.8; Δ15, 2.5, and Δ16, 1.9 (total trans 18∶1 acids in milk: %). That of cis‐18∶1 isomers was (proportions in % relative to total cis‐18∶1 isomers): Δ6–Δ8, 4.7; Δ9, 72.5; Δ10, 4.0; Δ11, 8.0; Δ12, 7.1; Δ13, 1.9; Δ14, 1.0, and Δ15, 0.7 (total cis‐18∶1 acids in milk: %). These results demonstrate that all isomeric acids, independent of the geometry and the position of the ethylenic bond, are incorporated into milk lipids. With regard to trans‐18∶1 isomers, the distribution profile in milk is identical to that in the dams' diet, i.e., there is no discrimination against any positional isomer between their ingestiona nd their deposition into milk lipids. As a consequence, this study indicates that the trans‐18∶1 isomer profile of milk reflects that in the dams' diet and supports our earlier hypothesis that the profile of trans‐18∶1 isomers in milk can be used to deduce the relative contribution of ruminant fats and partially hydrogenated oils in the diet ot the total intake of trans‐18∶1 isomers. On the other hand, the cis‐18∶1 isomer profile in milk shows significant differences when compared to that in the dams' diet. Surprisingly, there are no major differences for the cis‐Δ9 (oleic) and the cis‐Δ11 (asclepic) isomers, which can be synthesized by the mother. However, there seems to be a significant positive selectivity for the group cis‐Δ6–Δ8, and for the cis‐Δ12 isomer, whereas a negative selectivity occurs for the Δ10 and Δ13 to Δ15 cis isomers.
Isomers of hexadecenoic and hexadecadienoic acids in Androsace septentrionalis (Primulaceae) seed oil
Authors: Tsevegsuren N. , Aitzetmuller K. , Vosmann K.
Published: November 2006

Seeds of Androsace septentrionalis of the genus Androsace (tribus Primuleae) from the plant family Primulaceae were studied for their oil content and FA composition. The seed oil of A. septentrionalis was found to contain two unusual FA rarely occurring in plants: 11‐cis‐hexadecenoic acid (16∶1Δ11c or 16∶1n−5) and 9‐cis,12‐cis‐hexadecadienoic acid (16∶2Δ9c,12c or 16∶2n−4). It also contained an unusually high amount (21.4%) of 9‐cis‐hexadecenoic acid (palmitoleic acid; 16∶1Δ9c or 16∶1n−7), i.e., at a level higher than that of oleic acid, in addition to common FA. Compared with most plant seed oils, at 3.8% the level of 18∶1Δ11c (or 18∶1n−7) also was elevated. The nonidentity of the Androsace 16∶2‐acid with the 16∶2‐acid, which is very typical for Ranunculus spp., as well as its identity with the 16∶2‐acid typically found in Asclepiadaceae was established by co‐chromatography. The structure and composition of the constituent FA of A. septentrionalis were also determined by various chromatographic methods (TLC, Ag+‐TLC, capillary GLC) and spectroscopic methods (IR, GC‐MS). The significant deviation of the Androsace FA pattern from that of other Primuleae, indicating a separate phylogenetic position of Androsace, is discussed.
Tentative identification and quantification of TAG core aldehydes as dinitrophenylhydrazones in autoxidized sunflowerseed oil using reversed‐phase HPLC with electrospray lonization MS
Authors: Sjövall Olli , Kuksis Arnis , Kallio Heikki
Published: November 2006

The molecular species of TAG core aldehydes (aldehydes still esterified to parent molecules) were detected and quantified in dietary‐quality sunflowerseed oil autoxidized for 0‐18 d at 60°C in the dark. The analyses were performed by reversed‐phase HPLC with UV (358 nm) absorption or light scattering and electrospray ionization‐MS (ESI/MS) detection following preparation of the dinitrophenylhydrazone derivatives. Aldehyde production, as estimated by UV and ESI/MS, increased gradually over the 18‐d period following a rapid initial destruction of the core aldehydes accumulated during storage of the commercial oil at 10°C for 3 mon. The contents of hydroperoxides and hydroperoxide core aldehyde combinations were estimated to account for about 5% of total TAG, quantified as area in the chromatographic trace, after 18 d of autoxidation as estimated by an evaporative light scattering detector (ELSD). The major species of core aldehydes were tentatively identified as 9‐oxononanoyl (70%)‐, 12‐oxo‐9,10‐epoxydodecenoyl (10%)‐, and 13‐oxo‐9,11‐tridecadienoyl (5%)‐containing acylglycerols, plus smaller amounts of simple and mixed chain‐length dialdehydes, and hydroxy and epoxy monoaldehyde‐containing acylglycerols (15% of total). Quantitatively, the core aldehydes made up 2–12 g/kg of oil by UV detection and 2–9 g/kg of oil by EsI/MS detection, whereas the hydroperoxides measured in the unreduced state by HPLC with ELSD were estimated at 200 g/kg after 18 d of autoxidation. The major hydroperoxides of sunflowerseed oil were as previously identified.
Effect of ultrasonication and grinding on the determination of lipid class content of microalgae harvested on filters
Authors: Pernet Fabrice , Tremblay Réjean
Published: November 2006

To ensure complete lipid extraction of algal samples collected on glass fiber filters, one must facilitate the access of extracting solvent to the lipids by using ultrasonication, grinding, or a combination of these two methods. This study examines the effect of these three treatments, in combination with storage time and sampling volumes, on the determination of lipid class composition of the diatom Chaetoceros gracilis. The TAG level was significantly influenced by treatment in relation to either storage time or sampling volume. FFA and other degradation products increased markedly with storage time at the expense of TAG and phospholipids (PL). Finally, sampling volume and storage time interacted in their effects on TAG and PL contents in an inverse manner.
Occurrence of high levels of tetracosahexaenoic acid in the jellyfish Aurelia sp.
Authors: Nichols Peter D. , Danaher Kathryn T. , Koslow J. Anthony
Published: November 2006

The FA composition of the pelagic jellyfish Aurelia sp. collected from off‐shore Western Australia waters was determined by capillary GC and GC‐MS, with confirmation of PUFA structure performed by analysis of 4,4‐dimethyloxazoline derivatives. PUFA constituted 47.6% of the total FA, with the essential PUFA eicosapentaenoic acid (FPA), arachidonic acid, and DHA accounting for 34%. Of particular interest, the unusual very long chain PUFA 6,9,12,15,18,21‐tetracosahexaenoic acid (THA, 24∶6n−3) was present at 9.3%, and the rarely reported 6,9,12,15,18‐tetracosapentaenoic acid (24∶5n−6) also was detected at 0.8%. To our knowledge, this represents the first report of THA as a major PUFA in a pelagic marine organism.
Comparative effects of flaxseed and sesame seed on vitamin E and cholesterol levels in rats
Authors: Yamashita Kanae , Ikeda Saiko , Obayashi Mariko
Published: November 2006

Flaxseed and sesame seed both contain more than 40% fat, about 20% protein, and vitamin E, mostly γ‐tocopherol. Furthermore, both contain considerable amounts of plant lignans. However, flaxseed contains 54% α‐linolenic acid, but sesame seed only 0.6%, and the chemical structures of flaxseed and sesame lignans are different. In this study, we investigated the differential effects of flaxseed and sesame seed on plasma and tissue γ‐tocopherol, TBARS, and cholesterol concentrations. Rats were fed experimental diets for 4 wk: vitamin E‐free, (‐VE), γ‐tocopherol, flaxseed (FS), sesame seed (SS), flaxseed oil (FO), FO with sesamin (FOS), and defatted flaxseed (DFF). SS and FOS diets induced significantly higher γ‐tocopherol concentrations in plasma and liver compared with FS, FO, and DFF diets. Groups fed FS, FO, and FOS showed lower plasma total cholesterol compared with the SS and DFF groups. Higher TBARS concentrations in plasma and liver were observed in the FS and FO groups but not in the FOS groups. These results suggest that sesame seed and its lignans induced higher γ‐tocopherol and lower TBARS concentrations, whereas flaxseed lignans had no such effects. Further, α‐linolenic acid produced strong plasma cholesterol‐lowering effects and higher TBARS concentrations.
New glyceroglycolipid and ceramide from Premna microphylla
Authors: Zhan Zha‐Jun , Yue Jian‐Min
Published: November 2006

Iwo new compounds (1,2) were isolated from the ethanolic extract of the leaves of Premna microphylla, together with five known compounds. The structures of compounds 1 and 2 were elucidated as (2S,3S,4R,11E)‐2‐[(2R)‐2‐hydroxytetracosanoylamino]‐11‐octadecene‐1,3,4‐triol (1) and 1‐O(9Z,12Z, 15Z‐octadecatrienoyl)‐3‐O‐[β‐d‐galactopyranosyl‐(1→6)‐O‐β‐d‐galactopyranosyl‐(1→6)‐α‐d‐galactopyranosyl] glycerol (2) by means of spectroscopic and chemical methods.
Maternal fish oil supplementation in lactation: Effect on visual acuity and n−3 fatty acid content of infant erythrocytes
Authors: Lauritzen Lotte , Jørgensen Marianne H. , Mikkelsen Tina B. , Skovgaard Ib M. , Straarup Ellen‐Marie , Olsen Sjúrdur F. , Høy Carl‐Erik , Michaelsen Kim F.
Published: November 2006

Studies on formula‐fed infants indicate a beneficial effect of dietary DHA on visual acuity. Cross‐sectional studies have shown an association between breast‐milk DHA levels and visual acuity in breast‐fed infants. The objective in this study was to evaluate the biochemical and functional effects of fish oil (FO) supplements in lactating mothers. In this double‐blinded randomized trial, Danish mothers with habitual fish intake below the 50th percentile of the Danish National Birth Cohort were randomized to microencapsulated FO [1.3 g/d long‐chain n−3 FA (n−3 LCPUFA)] or olive oil (OO). The intervention started within a week after delivery and lasted 4 mon. Mothers with habitual high fish intake and their infants were included as a reference group. Ninety‐seven infants completed the trial (44 OO‐group, 53 FO‐group) and 47 reference infants were followed up. The primary outcome measures were: DHA content of milk samples (0, 2, and 4 mon postnatal) and of infant red blood cell (RBC) membranes (4 mon postnatal), and infant visual acuity (measured by swept visual evoked potential at 2 and 4 mon of age). FO supplementation gave rise to a threefold increase in the DHA content of the 4‐mon milk samples (P<0.001). DHA in infant RBC reflected milk contents (r=0.564, P<0.001) and was increased by almost 50% (P<0.001). Infant visual acuity was not significantly different in the randomized groups but was positively associated at 4 mon with infant RBC‐DHA (P=0.004, multiple regression). We concluded that maternal FO supplementation during lactation did not enhance visual acuity of the infants who completed the intervention. However, the results showed that infants with higher RBC levels of n−3 LCPUFA had a better visual acuity at 4 mon of age, suggesting that n−3 LCPUFA may influence visual maturation.
Fatty acids induce increased granulocyte macrophage‐colony stimulating factor secretion through protein kinase C‐activation in THP‐1 macrophages
Authors: Bahramian Nahid , Östergren‐Lundén Gunnel , Bondjers Göran , Olsson Urban
Published: November 2006

Insulin resistance and type 2 diabetes are associated with elevated circulating levels of nonesterified FA (NEFA) and lipoprotein remnants. The dyslipidemia is an important contributor to the excess arterial disease associated with insulin resistance and type 2 diabetes, but the mechanisms involved are elusive. In the present study we examined the effect of NEFA on macrophages. For this purpose, we utilized human macrophages, prepared by treating THP‐1 monocytes with phorbol ester. We found that albumin‐bound NEFA at physiological levels increase the secretion of granulocyte macrophage‐colony stimulating factor (GM‐CSF) by the THP‐1 macrophages in a dose‐dependent manner. The effect was registered as an increase in mRNA, and the amount of GM‐CSF secreted correlated with the accumulation of TAG and DAG in the cell. The NEFA‐induced rise in GM‐CSF appeared to be mediated by activation of protein kinase C, probably acting on extracellular signal‐regulated kinases 1 and 2 and being calcium dependent. We speculate that increased secretion of GM‐CSF by resident macrophages in the intima exposed chronically to high levels of NEFA, such as those present in insulin resistance, may contribute to a proatherogenic response of arterial cells.
Lipids rich in phosphatidylethanolamine from natural gas‐utilizing bacteria reduce plasma cholesterol and classes of phospholipids: A comparison with soybean oil
Authors: Müller Hanne , Hellgren Lars I. , Olsen Elisabeth , Skrede Anders
Published: November 2006

We compared the effects of three different high‐lipid diets on plasma lipoproteins and phospholipids in mink (Mustela vison). The 18 mink studied were fed one of the three diets during a 25‐d period in a parallel group design. The compared diets had 0,17, and 67% extracted lipids from natural gas‐utilizing bacteria (LNGB), which were rich in PE. The group with 0% LNGB was fed a diet for which the lipid content was 100% soybean oil. The total cholesterol, LDL cholesterol, and HDL cholesterol of animals consuming a diet with 67% LNGB (67LNGB‐diet), were significantly lowered by 35, 49, and 29%, respectively, and unesterified cholesterol increased by 17% compared with the animals fed a diet of 100% lipids from soybean oil (SB‐diet). In addition, the ratio of LDL cholesterol to HDL cholesterol was 27% lower in mink fed the 67LNGB‐diet than those fed the SB‐diet. When the mink were fed the 67LNGB‐diet, plasma PC, total phospholipids, lysoPC, and PI were lowered significantly compared with the mink fed a SB‐diet. Plasma total cholesterol was correlated with total phospholipids as well as with PC (R=0.8, P<0.001). A significantly higher fecal excretion of unesterified cholesterol, cholesteryl ester, PC, lysoPC, and PE was observed in the 67LNGB‐fed mink compared with the SB‐fed mink. We conclude that phospholipids from the 67LNGB‐diet decreased plasma lipoprotein levels, the LDL/HDL cholesterol ratio, and plasma phospholipid levels, especially lysoPC and PC, compared with the highly unsaturated soybean oil. Our findings indicate that the decrease of plasma cholesterol is mainly caused by a specific mixture of phospholipids containing a high level of PE, and not by the dietary FA composition. The lack of significant differences in the level of plasma PE due to the diets indicates that most of the PE from LNGB has been converted to PC in the liver. Thus, plasma cholesterol may at least be partly regulated by phospholipid methylation from PE to PC in the liver.
Multivariate prediction of clarified butter composition using raman spectroscopy
Authors: Beattie J. Renwick , Bell Steven E. J. , Borgaard C. , Fearon A. M. , Moss Bruce W.
Published: November 2006

Raman spectroscopy has been used to predict the abundance of the FA in clarified butterfat that was obtained from dairy cows fed a range of levels of rapeseed oil in their diet. Partial least squares regression of the Raman spectra against FA compositions obtained by GC showed that good prediction of the five major (abundance >5%) FA gave R2=0.74–0.92 with a SE of prediction (RMSEP) that was 5–7% of the mean. In general, the prediction accuracy fell with decreasing abundance in the sample, but the RMSEP was <10% for all but one of the 10 FA present at levels >1.25%. The Raman method has the best prediction ability for unsaturated FA (R2=0.85–0.92), and in particular trans unsaturated FA (best‐predicted FA was 18∶1tΔ9). This enhancement was attributed to the isolation of the unsaturated modes from the saturated modes and the significantly higher spectral response of unsaturated bonds compared with saturated bonds. Raman spectra of the melted butter samples could also be used to predict bulk parameters calculated from standard analyzes, such as iodine value (R2=0.80) and solid fat content at low temperature (R2=0.87). For solid fat contents determined at higher temperatures, the prediction ability was significantly reduced (R2=0.42), and this decrease in performance was attributed to the smaller range of values in solid fat content at the higher temperatures. Finally, although the prediction errors for the abundances of each of the FA in a given sample are much larger with Raman than with full GC analysis, the accuracy is acceptably high for quality control applications. This, combined with the fact that Raman spectra can be obtained with no sample preparation and with 60‐s data collection times, means that high‐throughput, on‐line Raman analysis of butter samples should be possible.
Inhibitory action of conjugated C18‐fatty acids on DNA polymerases and DNA topoisomerases
Authors: Mizushina Yoshiyuki , Tsuzuki Tsuyoshi , Eitsuka Takahiro , Miyazawa Teruo , Kobayashi Kanako , Ikawa Hiroshi , Kuriyama Isoko , Yonezawa Yuko , Takemura Masaharu , Yoshida Hiromi , Sakaguchi Kengo
Published: November 2006

We reported previously that unsaturated linear‐chain FA of the cis‐configuration with a C18‐hydrocarbon chain such as linoleic acid (18∶2Δ9c, 12c) could potently inhibit the activities of mammalian DNA polymerases and DNA topoisomerases, but their saturated forms could not. There are chemically two classes of unsaturated FA, normal and conjugated, but only the conjugated forms show potent antitumor activity. In this report, we study the inhibitory effects of chemically synthesized conjugated C18‐FA on mammalian DNA polymerases and DNA topoisomerases as compared with normal unsaturated FA. The conjugated α‐eleostearic acid (18∶3Δ9c, 11t, 13t) was the strongest of all the FA tested. For the inhibition, the conjugated form is crucially important. The energy‐minimized 3‐D structures of the FA were calculated, and both a length of less than 20 Å and a width of 8.13–9.24 Å in the C18‐FA structure were found to be important for enzyme inhibition. The 3‐D structure of the active site of both DNA polymerases and topoisomerases must have had a pocket to join α‐eleostearic acid, and this pocket was 12.03 Å long and 9.24 Å wide.
Asymmetric in vitro synthesis of diastereomeric phosphatidylglycerols from phosphatidylcholine and glycerol by bacterial phospholipase D
Authors: Sato Rina , Itabashi Yutaka , Hatanaka Tadashi , Kuksis Arnis
Published: November 2006

Using chiral‐phase HPLC, we determined the stereochemical configuration of the phosphatidylglycerols (PtdGro) synthesized in vitro from 1,2‐diacyl‐sn‐glycero‐3‐phosphocholine (PtdCho, R configuration) or 1,2‐diacyl‐sn‐glycero‐3‐phosphoethanolamine (PtdEtn, R configuration) and glycerol by transphosphatidylation with bacterial phospholipase D (PLD). The results obtained with PLD preparations from three Streptomyces strains (S. septatus TH‐2, S. halstedii K5, and S. halstedii subsp. scabies K6) and one Actinomadura species were compared with those obtained using cabbage and peanut PLD. The reaction was carried out at 30°C in a biphasic system consisting of diethyl ether and acetate buffer. The resulting PtdGro were then converted into bis(3,5‐dinitrophenylurethane) derivatives, which were separated on an (R)‐1‐(1‐naphthyl)ethylamine polymer. In contrast to the cabbage and peanut PLD, which gave equimolar mixtures of the R,S and R,R diastereomers, as previously established, the bacterial PLD yielded diastereomixtures of 30–40% 1,2‐diacyl‐sn‐glycero‐3‐phospho‐1′‐sn‐glycerol (R,S configuration) and 60–70% 1,2‐diacyl‐sn‐glycero‐3‐phospho‐3′‐sn‐glycerol (R,R configuration). The highest disproportionation was found for the Streptomyces K6 species. The present study demonstrates that bacterial PLD‐catalyzed transphosphatidylation proceeds to a considerable extent stereoselectively to produce PtdGro from PtdCho or PtdEtn and prochiral glycerol, indicating a preference for the sn‐3′ position of the glycerol molecule.
Effects of dietary n−3 polyunsaturated fatty acids on T‐Cell membrane composition and function
Authors: Switzer Kirsten C. , McMurray David N. , Chapkin Robert S.
Published: November 2006

Dietary n−3 PUFA have been shown to attenuate T‐cell‐mediated inflammation, in part, by suppressing T‐cell activation and proliferation. n−3 PUFA have also been shown to promote apoptosis, another important mechanism for the prevention of chronic inflammation by maintaining T‐cell homeostasis through the contraction of populations of activated T cells. Recent studies have specifically examined Fas death receptor‐mediated activation‐induced cell death (AICD), since it is the form of apoptosis associated with peripheral T‐cell deletion involved in immunological tolerance and T‐cell homeostasis. Data from our laboratory indicate that n−3 PUFA promote AICD in T helper 1 polarized cells, which are the mediators of chronic inflammation. Since Fas and components of the deathinducing signaling complex are recruited to plasma membrane microdomains (rafts), the effect of dietary n−3 PUFA on raft composition and resident protein localization has been the focus of recent investigations. Indeed, there is now compelling evidence that dietary n−3 PUFA are capable of modifying the composition of T‐cell membrane microdomains (rafts). Because the lipids found in membrane microdomains actively participate in signal transduction pathways, these results support the hypothesis that dietary n−3 PUFA influence signaling complexes and modulate T‐cell cytokinetics in vivo by altering T‐cell raft composition.