bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cuticular waxes from Ivy leaves (Hedera helix L.): analysis of high‐molecular‐weight esters
Authors: Santos Sara , Schreiber Lukas , Graça José 
Published: November 2006

AbstractSoluble waxes were extracted from the cuticle of ivy (Hedera helix L.) leaves with dichloromethane in a yield of ca. 13%. The cuticular waxes were directly analysed by GC‐MS, high‐temperature GC‐MS and ESI‐MS/MS. The GC‐MS analysis showed mostly n‐alkanols (45.3%), monoacids (18.8%), triterpenes (9.7%), n‐aldehydes (8.7%) and n‐alkanes (7.7%). The high‐temperature GC‐MS and the ESI‐MS/MS analyses showed the presence of ester waxes, namely alkyl alkanoates and alkyl coumarates. Alkyl alkanoates comprised esters of the hexadecanoic acid with n‐alkanols ranging from C16 to C34. Alkyl coumarates included esters of coumaric acid with n‐alkanols ranging from C16 to C32. The cuticular waxes were hydrolysed and the resulting organic and aqueous phases analysed by GC‐MS. The hydrolysate showed a major increase in the quantities of n‐alkanols, hexadecanoic acid and coumaric acid derived from the alkyl and acyl moieties from the ester waxes. A content of ester waxes of 38% was estimated based on the results from the GC‐MS analysis of the non‐hydrolysed and hydrolysed cuticular waxes. Alkyl alkanoates were analysed by ESI‐MS/MS as [M + Li]+ adduct ions and the alkyl coumarates as [M − H]− deprotonated ions. The ESI‐MS/MS analysis allowed the detection of a wider range of ester waxes than high‐temperature GC‐MS, and was shown to be a useful technique for the qualitative analysis of ester waxes from plant cuticles. Copyright © 2006 John Wiley & Sons, Ltd.
Solid state 19F NMR study of crystal transformation in PVDF and its nanocomposites
Authors: Pallathadka Pramoda K. , Tay S.S. , Tianxi Liu , Sprenger Peter 
Published: November 2006

AbstractThe polymorphism of poly(vinylidene fluoride) (PVDF) and its nanocomposites was studied by means of solid state nuclear magnetic resonance spectroscopy. 13C cross polarization magic angle spinning (13C CP MAS) NMR spectra were recorded using simultaneous high‐power decoupling on both the proton and fluorine channels. Both 1H → 13C and 19F → 13C CP experiments were conducted, giving identical results apart from intensity variations due to the CP efficiency. Two main resonances for the CF2 and the CH2 groups were observed for both neat PVDF (PVDF‐C0) and the nanocomposite containing 2 wt% clay (PVDF‐C2) samples. 19F CP MAS spectra were obtained from long proton spin‐lock experiments with a shorter contact time. The results showed two strong resonances at −84 and −98 ppm with equal intensities, representing the α‐form crystalline structure of PVDF. It was shown that the clay induces the crystallization of PVDF in β‐form. Our earlier investigations using thermal analysis and X‐ray scattering methods also showed crystal transformation of PVDF in its clay nanocomposites. POLYM. ENG. SCI. 46:1684–1690, 2006. © 2006 Society of Plastics Engineers
Positional distribution of CLA in TAG of lamb tissues
Authors: Paterson Lyn J. , Weselake Randall J. , Mir Priya S. , Mir Zahir 
Published: November 2006

AbstractThe content and positional distribution of CLA in TAG fractions of lamb tissues was examined with either preformed CLA or the linoleic acid precursor of CLA in the diet as experimental treatments. The CLA content of phospholipid (PL) from these tissues was also examined. Thirteen lambs were randomized to the following dietary treatments: (i) control diet (no supplement); (ii) CLA supplementation (0.33 g d−1 for 21 d prior to weaning) to milk‐replacer of pre‐ruminating lambs, or (iii) feeding linoleic acid‐rich oil (6% safflower oil on a dry matter basis) to weaned ruminating lambs. At slaughter, tissue samples were procured from diaphragm, rib muscle, and subcutaneous (SC) adipose tissue. Safflower oil supplementation in the diet resulted in an increase in CLA content of the TAG from diaphragm, rib muscle, and SC adipose tissue by about threefold (P<0.05) on a mol% basis. CLA was localized to the sn‐1/3 positions of TAG. Animals that received pre‐formed CLA, however, had increased proportions of CLA at the sn‐2 position of TAG from SC adipose tissue, suggesting that there were tissue‐specific dietary effects and possible age‐related effects on the mode of FA incorporation into TAG. Safflower oil supplementation in the diet had no effect on the CLA content of PL from diaphragm, rib muscle, and SC adipose tissue, suggesting that CLA was preferentially incorporated into the TAG of these tissues.
Dietary CLA alters yolk and tissue FA composition and hepatic histopathology of laying hens
Authors: Cherian Gita , Holsonbake Troy B. , Goeger Mary P. , Bildfell Rob 
Published: November 2006

AbstractThe effect of dietary CLA along with n‐3 PUFA on yolk FA profile and hepatic lipid accumulation was investigated. Laying hens (n=40) were randomly assigned to four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n‐3 PUFA. Dietary CLA did not affect the total lipid content of egg yolk (P>0.05). The amounts of CLA isomers (cis‐9 trans‐11, trans‐10 cis‐12) in the egg yolk were proportional to the levels of CLA in the diet (P<0.05). The total CLA content in the egg yolk was 0, 0.97, 2.4, and 5.3 wt%, respectively (P<0.05). Addition of CLA resulted in an increase in saturated FA (P<0.05) with a concomitant reduction in monounsaturated FA (P<0.05) in the yolk, liver, abdominal fat, breast, and thigh muscle. No difference in saturated and monounsaturated FA content in heart and spleen tissue was noted. Dietary CLA at all concentrations resulted in an increase (P<0.05) in the total number of fat vacuoles and lipid infiltration in hepatocytes. The number of cells with 75% or higher lipid vacuolation in the cytoplasm was also increased (P<0.05) by 2.0% CLA. Dietary CLA at 0.5% levels resulted in an increase (P<0.05) in the total lipid content of hepatic tissue. The total lipid content in leg muscle was lower (P<0.05) in CLA‐fed birds. However, no effect of CLA on lipid content of breast muscle, heart, spleen and adipose tissue was observed (P>0.05). The current study used CLA in a FFA form. The effects of using CLA in other form such as TG on avian hepatic tissue need to be investigated.
Impaired lipoprotein metabolism in obese offspring of streptozotocin‐induced diabetic rats
Authors: Merzouk Hafida , Madani Sihem , Hichami Aziz , Prost Josiane , Moutairou Kabirou , Belleville Jacques , Khan Naim Akhtar 
Published: November 2006

AbstractThe time course of changes in lipoprotein metabolism of obese offspring of mildly diabetic rats was studied with respect to serum lipoprotein composition as well as LCAT and tissue lipoprotein lipase (LPL) activities. Mild hyperglycemia in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. At birth, obese pups had higher serum glucose, insulin, and lipoprotein (VLDL, LDL‐HDL1, HDL2–3) levels than control pups. After 1 mon of life, all of these parameters in obese rats became similar to those of controls. However, LCAT, adipose tissue LPL, and hepatic triacylglycerol lipase activities were high. At 2 mon of age, VLDL‐TAG levels were higher in obese females than in controls. By the age of 3 mon, obese offspring had developed insulin resistance with hyperglycemia, hyperinsulinemia, and higher serum lipoprotein concentrations. Indeed, qualitative abnormalities of lipoproteins were seen and were typical of obese and diabetic human beings. Fetal hyperinsulinemia should be considered as a risk factor for later metabolic diseases, including dyslipoproteinemia.
High oleic acid oil suppresses lung tumorigenesis in mice through the modulation of extracellular signal‐regulated kinase cascade
Authors: Yamaki Tatsuya , Yano Tomohiro , Satoh Haruna , Endo Tatsuo , Matsuyama Chinami , Kumagai Hitomi , Miyahara Mitsuyoshi , Sakurai Hidetoshi , Pokorny Jan , Shin Sung Jae , Hagiwara Kiyokazu 
Published: November 2006

AbstractThis study was undertaken to estimate the effect of dietary high oleic acid oil (OA) on 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK)‐induced lung tumorigenesis in mice. Diet containing 10% oil was fed to mice through experimental periods. On day 30 after NNK injection (100 mg/kg body weight, i.p.), the treatment increased the level of prostaglandin E2 (PGE2) as well as proliferating cell nuclear antigen, a marker of cell proliferation in a high linoleic acid oil (LA)‐fed group but not in an OA‐fed group. The NNK treatment also induced the activation of an extracellular signal‐regulated kinase (Erk) cascade (Erk, Mek and Raf‐1) in an LA‐fed group. On the other hand, OA feeding abolished the NNK‐induced activation of the Erk cascade. In conjugation with these events, OA feeding reduced lung tumor incidence and tumor multiplicity (percentage of mice with tumors) in mice compared with LA feeding at the 20th experimental week. These results suggest that OA suppresses lung tumorigenesis and that this suppression is correlated with the inhibition of PGE2 production and inactivation of the Erk cascade.
Enrichment of LDL with EPA and DHA decreased oxidized LDL‐induced apoptosis in U937 cells
Authors: Wu Tianying , Geigerman Cissy , Lee Ye‐Sun , Wander Rosemary C. 
Published: November 2006

AbstractOxidized LDL (oxLDL) may contribute to the accumulation of apoptotic cells in atherosclerotic plaques. Although it is well established in monophasic chemical systems that the highly unsaturated EPA and DHA will oxidize more readily than FA that contain fewer double bonds, our previous studies showed that enrichment of LDL, which has discrete polar and nonpolar phases, with these FA did not increase oxidation. The objective of this study was to compare the extent of apoptosis induced by EPA/DHA‐rich oxLDL to that induced by EPA/DHA‐non‐rich oxLDL in U937 cells. LDL was obtained from one healthy subject three times before and after supplementation for 5 wk with 15 g/d of fish oil (FO), an amount easily obtainable from a diet that contains fatty fish. After supplementation, an FPA/DHA‐rich LDL was obtained. Oxidative susceptibility of LDL, as determined by measuring the formation of conjugated dienes and the accumulation of cholesteryl ester hydroperoxides, was not higher in EPA/DHA‐rich LDL. The oxLDL‐induced cell apoptosis was detected by the activation of caspase‐3, the translocation of PS to the outer surface of the plasma membrane using the Annexin V‐fluorescein isothiocyanate binding assay, and the presence of chromatin condensation and nuclear fragmentation using the 4,6‐diamidino‐2‐phenylindole staining assay All three measures showed that after FO supplementation, EPA/DHA‐rich oxLDL‐induced cell apoptosis decreased. The decrease was not related to the concentration of lipid hydroperoxides. This study suggests that a possible protective effect of EPA/DHA‐rich diets on atherosclerosis may be through lessening cell apoptosis in the arterial wall.
Evaluation of two GC columns (60‐m SUPELCOWAX 10 and 100‐m CP sil 88) for analysis of milkfat with emphasis on CLA, 18∶1, 18∶2 and 18∶3 isomers, and short‐ and long‐chain FA
Authors: Kramer John K. G. , Blackadar C. Brian , Zhou Jianqiang 
Published: November 2006

AbstractMilkfat is a complex mixture of many diverse FA, some of which have demonstrated health benefits including anticancer properties. Attempts are under way to enrich milkfats with long‐chain n−3 PUFA and CLA. It has been recommended that the analysis of these milkfats requires gas chromatography (GC) equipped with long, highly polar capillary columns. However, many analyses have been reported using CARBOWAXTM type (polyethylene glycol) capillary columns, such as SUPELCOWAX 10, even though the separation characteristics of many of the FA and their isomers present in milkfats have not been described in detail. This includes the isomers of CLA, cis‐ and trans‐octadecenoic acid (18∶1), linoleic acid (18∶2n−6), and linolenic acid (18∶3n−3), and the long‐chain PUFA. On the other hand, the resolution of these FA and their isomers has been more fully described using the highly polar capillary columns, such as CP Sil 88 and SP2560 because of the improved resolution obtained using these polar columns. The present study was undertaken to characterize the separation of these FA present in milkfats using a 60‐m SUPELCOWAX 10 column, to compare the results to those from a 100‐m CP Sil 88 column, and to determine if these two columns could possibly serve to complement each other for the analysis of total milkfat. The advantages of the SUPELCOWAX 10 column were a better resolution of the short‐chain saturated from their monounsaturated FA (MUFA) analogs, and a complete separation of the α‐linolenic (18∶3n−3) and eicosadecenoic acid (20∶1) isomers. It also provided an alternative elution order of the linoleic (18∶2n−6), 18∶3n−3 and γ‐linolenic (18∶3n−6) acid isomers. On the other hand, the CP Sil 88 column provided a better resolution of the CLA isomers, MUFA, the isolated cis and trans MUFA fractions, the PUFA, and many the 18∶2n−6 and 18∶3n−3 isomers. A complete analysis of milk lipids using the CP Sil 88 column required the prior separation of total FAME using silver ion‐TLC. The results of the present study confirm that the 100‐m highly polar capillary GC columns are mandatory for the analysis of milk lipids, and at best, the 60 m SUPELCOWAX 10 capillary column serves as a complementary GC column to provide different separations in certain regions based on its intermediate polarity.
Isolation and characterization of a Δ5 FA desaturase from Pythium irregulare by heterologous expression in Saccharomyces cerevisiae and oilseed crops
Authors: Hong Haiping , Datla Nagamani , Mackenzie Samuel L. , Qiu Xiao 
Published: November 2006

AbstractBy using the polymerase chain reaction approach with two degenerate primers targeting the heme‐binding and the third histidine‐rich motifs in microsomal carboxyl‐directed desaturases, we identified a cDNA PiD5 from Pythium irregulare encoding a Δ5 desaturase. The substrate specificity of the enzyme was studied in detail by expressing PiD5 in a yeast (Saccharomyces cerevisiae) mutant strain, AMY‐2α, where ole1, a Δ9 desaturase gene, is disrupted. The result revealed that the encoded enzyme could desaturate unsaturated FA from 16 to 20 carbons beginning with Δ9 and Δ11 as well as Δ8 ethylenic double bonds. Introduction of PiD5 into Brassica juncea under the control of a CaMV 35S constitutive promoter resulted in accumulation of several Δ5‐unsaturated polymethylene‐interrupted FA (Δ5‐UPIFA) including 18∶2−5,9, 18∶2−5,11, 18∶3−5,9,12, and 18∶4−5,9,12,15 in vegetative tissues. The transgenic enzyme could also desaturate the exogenously supplied homo‐γ‐linolenic acid (20∶3−8,11,14) to arachidonic acid (20∶4−5,8,11,14). Introduction of PiD5 into B. juncea and flax under the control of seed‐specific promoters resulted in production of Δ5‐UPIFA, representing more than 10% of the total FA in the seeds.
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

AbstractPrevious 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

AbstractThe 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

AbstractMost 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

AbstractSimultaneous 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.