bluuebunny/crossref_metadata_2025 huggingface dataset:
The steryl ester and phospholipid fatty acids of the spongeAgelas conifera from the Colombian Caribbean
Authors: Duque Carmenza , Cepeda Nestor , Martínez Alejandro
Published: November 2006

The steryl ester and phospholipid fractions of the marine spongeAgelas conifera were isolated and analyzed. The fatty acyl components of the steryl ester and phospholipid fractions as determined by gas chromatography and gas chromatography/mass spectrometry were very similar and consisted of 56.8 and 62.7% of C14−C20 acids (normal; branched, especiallyiso andanteiso; and monounsaturated, particularly Δ9 and Δ11 acids) and of 43.1 and 35.5% of C24−C26 acids (Δ5,9 diunsaturated acids), respectively. The major constituent fatty acids detected were 13‐methyltetradecanoic,n‐hexadecanoic, 10‐methylhexadecanoic, 11‐octadecenoic, 12‐methyloctadecanoic, 5,9‐pentacosadienoic and 5,9‐hexacosadienoic acids. The phospholipids isolated were identified as phosphatidylcholine (37%), phosphatidylserine (34%), phosphatidylethanolamine (16%) and phosphatidylinositol (11%). The distribution of fatty acids within the phospholipid classes was also determined.
Age‐related accumulation of phosphatidylcholine hydroperoxide in cultured human diploid cells and its prevention by α‐tocopherol
Authors: Suzuki Toshihide , Miyazawa Teruo , Fujimoto Kenshiro , Otsuka Miki , Tsutsumi Masako
Published: November 2006

The levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population doubling levels were determined by high‐performance liquid chromatography combined with chemiluminescence detections. This methodology utilizes a mixture of cytochromec and luminol as post‐column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased with age from 0.34 to 27.72 pmol/106 cells. At the end of the cells'in vitro lifespan (51st population doubling level), the hydroperoxide content per 106 cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous α‐tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extent the lifespanin vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging of human fetal liploid fibroblasts.
Occurrence of n−5 monounsaturated fatty acids in jujube pulp lipids
Authors: Yamamoto Kohei , Shibahara Akira , Sakuma Akiko , Nakayama Takao , Kajimoto Goro
Published: November 2006

The pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis‐monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic (cis‐9‐hexadecenoic) acid andcis‐vaccenic (cis‐11‐octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance of n−5 monoenoic acid isomers.
Lyso platelet activating factor (LysoPAF) and its enantiomer. Total synthesis and carbon‐13 NMR spectroscopy
Authors: Murari M. P. , Murari R. , Parthasarathy S. , Guy C. A. , Kumar V. V. , Malewicz B. , Baumann Wolfgang J.
Published: November 2006

Described is a reaction sequence for the total synthesis of lyso platelet activating factor (lysoPAF; 1‐O‐alkyl‐sn‐glycero‐3‐phosphocholine) and its enantiomer. The procedure is versatile and yields optically pure isomers of defined chain length. The synthesis is equally suited for the preparation of lysoPAF analogues and its enantiomers with unsaturation in the long aliphatic chain. First,rac‐1(3)‐O‐alkylglycerol is prepared by alkylation ofrac‐isopropylideneglycerol with alkyl methanesulfonate followed by acid‐catalyzed removal of the ketal group. The primary hydroxy group of alkylglycerol is then protected by tritylation, the secondary hydroxy group is acylated, and the protective trityl group is removed under mild acidic conditions with boric acid on silicic acid, essentially without acyl migration. Condensation of the diradylglycerol with bromoethyl dichlorophosphate in diethyl ether, hydrolysis of the resulting chloride, and nucleophilic displacement of the bromine with trimethylamine givesrac‐1‐O‐alkyl‐2‐acylglycero‐3‐phosphocholine in good overall yield. The racemic alkylacylglycerophosphocholine is finally treated with snake venom phospholipase A2 (Ophiophagus hannah) which affords 1‐O‐alkyl‐sn‐glycero‐3‐phosphocholine (lysoPAF) of natural configuration in optically pure form. The “unnatural” 3‐O‐alkyl‐2‐O‐acyl‐sn‐glycerol‐1‐phosphocholine enantiomer, which is not susceptible to phospholipase A2 cleavage, gives 3‐O‐alkyl‐sn‐glycero‐1‐phosphocholine upon deacylation with methanolic sodium hydroxide. Homogeneity and structure of the intermediates and final products were ascertained by carbon‐13 nuclear magnetic resonance spectroscopy on monomeric solutions.
Effects of free fatty acids on the binding of steroid hormones to bovine serum albumin
Authors: Watanabe Sadao , Tani Takayuki , Watanabe Shigenobu , Senō Manabu
Published: November 2006

The effects of binding of free fatty acids (FFA) to bovine serum albumin (BSA) on steroid hormone binding to BSA were examined. The FFA studied included myristic, palmitic, stearic, oleic and linoleic acids. The binding coefficient K was estimated from the changes in the equilibrium partition coefficient between the aqueous and the hexane phase caused by the addition to BSA to the aqueous phase. A noticeable effect of FFA binding (molar ratio FFA/BSA, 2∶1) on the affinities of α‐estradiol, ethynylestradiol and dehydroisoandrosterone to BSA was not observed: however, the affinities of progesterone, androsterone and testosterone were distinctly enhanced by FFA binding. Furthermore, the elution profiles of gel filtration chromatography clearly showed that progesterone and testosterone are easily liberated from the hormone/BSA complexes and that stronger binding of these hormones to BSA is caused by binding of FFA to BSA. The affinity of ethynylestradiol to BSA is stronger than that of progesterone and testosterone and is not affected by palmitic acid binding to BSA.
Erythrocyte membrane lipid alterations in undernourished cerebral palsied children during high intakes of a soy oil‐based enteral formula
Authors: Harper Mary Ellen , Patrick John , Kramer John K. G. , Wolynetz Mark S.
Published: November 2006

Five undernourished children with severe cerebral palsy (CP) were tube‐fed sufficient volumes of IsocalTM to allow rapid weight gain. IsocalTM provided, on average, 88% of their daily energy intake for at least 25 days. The purpose of our study was to correct the undernutrition and to analyze the major erythrocyte phospholipids before and after feeding periods for possible feeding and disease‐related differences. The fatty acid profiles of erythrocyte membranes from CP children were compared with those from 12 healthy children and with the fatty acid composition of the formula. There were no clinical or biochemical indications of essential fatty acid deficiency. The feeding of a soy oil‐based formula increased the proportions of 18∶2n−6 in the phospholipids. The increases occurred predominantly in phosphatidylcholine followed by phosphatidylethanolamine. Despite such large dietary intakes of soy oil, no changes were observed in the phospholipid concentrations of 20∶4n−6, 18∶3n−3, 20∶5n−3, or in the C22n−6 and C22n−3 fatty acids. These findings are consistent with an inhibition of the Δ6 desaturase by high dietary linoleate.
Selective reduction of fatty acid oxidation in colonocytes: Correlation with ulcerative colitis
Authors: Roediger W. E. W. , Nance S.
Published: November 2006

Attempts were made to define which fatty acid (2∶0 to 18∶1) was optimally oxidized by isolated colonocytes (colonic epithelial cells) and to select inhibitors of fatty acid oxidation which would be analogous in their action to the inhibition of fatty acid oxidation observed in colonocytes involved with ulcerative colitis. Isolated colonic epithelial cells of Sprague‐Dawley rats were used with 2‐mercaptoacetate, dichloroacetate, 3‐mercaptopropionate, 4‐mercaptobutyrate, 4‐sulfatebutyrate, 2‐bromobutyrate, sulfite ions and nitrite ions. n‐Butyrate (4∶0) was maximmaly oxidized to CO2 and ketone bodies (mean value 5.46 μmol/min/g dry wt). Oxidation of butyrate to CO2 was diminished by 2‐bromobutyrate, sulfite ions and all mercapto fatty acids. Both fatty acid oxidation and glucose oxidation were significantly inhibited by 2‐bromobutyrate, while mercapto fatty acids and sulfite inhibited fatty acid oxidation (p<0.01) without significantly changing glucose oxidation. Observation with 2‐mercaptoacetate and sulfite correlate with early changes of fatty acid oxidation observed in cases of ulcerative colitis, and warrant further study with isolated colonocytes of man.
Metabolic fate of sphingomyelin of high‐density lipoprotein in rat plasma
Authors: Bentejac Marc , Bugaut Maurice , Delachambre Marie Claire , Lecerf Jean
Published: November 2006

The metabolic fate of high density lipoprotein (HDL) sphingomyelin in plasma was studied in rats over a 24‐hr period after injection of HDL containing sphingomyelin which was14C‐labeled in the stearic (18∶0) or lignoceric acid (24∶0) moiety and3H‐labeled in the choline methyl groups. Decay of label in plasma followed three phases. The first two phases were similar for both isotopes and both types of sphingomyelin (t1/2≃10 and 110 min). However, during the third phase (from 10 hr after injection),3H label disappeared more slowly than14C label from 18∶0 sphingomyelin, whereas the3H/14C ratio remained relatively constant when 24∶0 sphingomyelin was used. Intact, doubly‐labeled 18∶0 sphingomyelin disappeared from HDL rapidly (t1/2=38 min) by tissue uptake and by transfer to very low density lipoprotein (VLDL). VLDL contained up to 12% of the sphingomyelin 1 hr after injection. This is the first demonstration of a transferin vivo of sphingomyelin from HDL to VLDL. A similarly rapid transfer was also observedin vitro. Some nontritated, [14C]18∶0 or [14C]24∶0 sphingomyelin was redistributed more slowly into HDL. Doubly‐labeled phosphatidylcholine appeared in VLDL and HDL within 1 hr after injection and reached 1.8 and 2.1% of the injected14C and3H in VLDL at 1 hr, and 4.8 and 6.9% in HDL at 3 hr, respectively.
A fluorimetric method for measuring lipase activity based on umbelliferyl esters
Authors: de Monpezat Thierry de Laborde , de Jeso Bernard , Butour Jean‐Luc , Chavant Louis , Sancholle Michel
Published: November 2006

A new fluorimetric method for measuring lipase activity is described. The fluorescent compound umbelliferone (UMB) was esterified with various unsaturated and saturated fatty acids of different carbon chain lengths, and the non‐fluorescent esters were used as substrates for measuring the activity of two lipases purified fromRhizopus delemar andCandida cylindracea. The fluorescence intensity of UMB liberated by hydrolysis of the substrates gives an indication of the lipase activity towards the respective esters. UMB was found to be somewhat more sensitive and stable than 4‐methylumbelliferone (4‐MU), which has been used previously. The highly sensitive method (nmoles UMB/mL/hr) described here was tested on five different esters. The method has the advantage of not requiring extraction of the lipolysis products. It also can be carried out quickly, in two to three minutes, and thus lends itself to the screening of lipase‐producing micro‐organisms. The method offers an interesting alternative or can be complementary to assays based on the use of 4‐methylumbelliferone esters as substrates.
Studies on the transfer of tocopherol between lipoproteins
Authors: Traber Maret G. , Lane Jerome C. , Lagmay Nora R. , Kayden Herbert J.
Published: November 2006

The net transfer of labeled α‐tocopherol from donor to acceptor lipoproteins at physiological concentrations was investigated. Labeled lipoproteins were isolated i) followingin vitro addition of [3,4‐3H]all rac‐α‐tocopherol to plasma, or ii) from plasma obtained 12–16 h after ingestion by normal subjects of an oral dose (100 mg each) of 2R,4′R,8′R‐α‐[5,7‐(C2H3)2]tocopheryl acetate and 2S,4′R′,R‐α‐[5‐C2H3]tocopheryl acetate. A constant amount (on a protein basis) of labeled lipoprotein was incubated with an increasing amount of unlabeled acceptor lipoprotein for 2 h at 37°C. No discrimination between stereoisomers of α‐tocopherol was detected. Labeled VLDL and labeled LDL (very low and low density lipoproteins, respectively) tended to retain their labeled tocopherol. Labeled high density lipoproteins (HDL) readily transferred the labeled tocopherol to VLDL (>60% transferred), while the transfer to LDL was dependent upon the ratio of labeled HDL/LDL with a lower net transfer at higher ratios. This dependency of the distribution of tocopherol upon the ratio of HDL/LDL was also observedin vivo. The tocopherol/mg HDL protein was measured in 11 subjects with varying HDL levels. As the %HDL in the plasma increased from 14 to 50%, the tocopherol/HDL protein also increased (r2=0.37,P<0.05).
Lipoprotein receptor mediated metabolism of [14C]arachidonic acid labeled chylomicron remnants by Hep G2 cells
Authors: Chen Qi , Florén Claes‐Henrik , Nilsson Åke
Published: November 2006

During lipolysis of chylomicron triacylglycerol by lipoprotein lipase, arachidonic acid (AA) esters are hydrolyzed at a slower rate than the predominant 16–18 carbon fatty acid esters. The further metabolism of the AA that is hereby enriched in the chylomicron remnant acylglycerols has not been investigated. In the present study, we examined the low density lipoprotein (LDL) dependent and independent metabolism of [14C]AA present in chylomicron remnants in the human hepatoma cell line Hep G2. Mesenteric duct cannulated rats were fed [14C]AA and [3H]cholesterol in corn oil, and the chyle obtained was injected intravenously into hepatectomized rats to form chylomicron remnants labeled with [14C]AA in the triacylglycerol (TG) and with3H in the cholesteryl ester portion. The remnants were then incubated with Hep G2 cells. The uptake of [14C]AA within 2–4 h was similar to that of [3H]cholesteryl ester. After uptake into the cells, [14C]AA was preferentially incorporated into phospholipids, a high proportion being found in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol. [14C]AA and [3H]cholesteryl ester uptake were influenced to similar extents by factors unknown to regulate the LDL receptor and by an anti‐LDL receptor antibody. Addition of compactin thus increased the uptake of [14C]AA by 50% in 4 h and mevalonolactone decreased the uptake by 86%. Using an anti‐LDL receptor antibody, 25.0% of [3H]cholesterol/cholesteryl ester and 37.7% of [14C]AA binding to the cells at 4°C were blocked. There was no lipolysis of [14C]TG or [14C]diacylglycerol by lipase secreted into the medium during incubations. The study shows that after the uptake of chylomicron remnants by Hep G2 cells, which in part occursvia the LDL receptor, AA is liberated from the acylglycerols and is preferentially incorporated into phospholipids.
Myogenic differentiation of the muscle clonal cell line BC3H‐1 is accompanied by changes in its lipid composition
Authors: Pediconi M. F. , Politi L. E. , Bouzat C. B. , De Los Santos E. B. , Barrantes F. J.
Published: November 2006

Phospholipid and neutral lipid composition was studied in the course of myogenic differentiation of the clonal cell line BC3H‐1. Total phospholipid content increased during differentiation, predominantly in the major classes of choline and ethanolamine glycerophospholipids. The contents of other lipids, such as triacylglycerols, diminished more than 50% during this period. The content and distribution of fatty acids also underwent marked differentiation‐dependent changes. The polyunsaturated (tetrapenta‐ and hexaenoic) fatty acid species of several phospholipid classes diminished during differentiation, especially those in choline, serine and inositol glycerophospholipids. Most noticeable were the changes in phosphatidylserine; long‐chain fatty acids having 20 to 22 carbon atoms and 4 to 6 double bonds decreased from about 30 to about 10 mol%. Although increased levels of saturation in other phospholipid fatty acyl chains appear to accompany the myogenic changes of BC3H‐1 cells, some unsaturated fatty acids, such as oleic acid (18∶1), increased by as much as 80% during the same period, suggesting the activation of a Δ9 desaturase. Sphingomyelin contained only saturated and monoenoic fatty acids and exhibited a four‐ to five‐fold decrease in its content of monoenoic acyl groups. Diacylglycerols became enriched in arachidonate and docosahexaenoate. The amount of cholesterol and its esters increased slightly during differentiation of BC3H‐1 cells. The data show that several metabolic pathways change during myogenic differentiation of the BC3H‐1 clonal cell line, particularlyde novo biosynthetic pathways, elongation/desaturation reactions, and acyl chain turnover. As a consequence of this, the lipid composition of the myoblast form of the BC3H‐1 cell, in which the nicotinic acetylcholine receptor and other cell surface receptors are expressed, is thus different from that of the nondifferentiated cell.
Specificity of soybean lipoxygenase‐1 in hydrated reverse micelles of sodiumbis(2‐ethylhexyl)sulfosuccinate (aerosol OT)
Authors: Shkarina Tatyana N. , Kühn Hartmut , Schewe Tankred
Published: November 2006

Soybean lipoxygenase‐1 (EC 1.13.11.33) was purified by fast protein liquid chromatography on a MONO Q column and studied with respect to the conversion of linoleic and arachidonic acids in reverse micelles of sodiumbis(2‐ethylhexyl)sulfosuccinate inn‐octane. In this system the specific activities were lower by one order of magnitude than those in the corresponding aqueous system. High‐performance liquid chromatography analyses indicated the predominant formation of 13S‐hydroperoxy‐9Z,11E‐octadecadienoic acid (13‐HpODE) from linoleic acid and of 15S‐hydroperoxy‐5Z,8Z,11Z,13E‐eicosatetraenoic acid (15) from arachidonic acid both in the aqueous system and in the reverse micelles. After sedimentation of the hydrated reverse micelles by ultracentrifugation, both linoleic acid and 13‐HpODE were found to be enriched in the micelles with only small amounts of these compounds present inn‐octane. It is proposed that substrates and products of the lipoxygenase reaction are located mainly in the surfactant shell of the hydrated reverse micelles and reach the micelle‐entrapped enzyme by diffusion into the aqueous interior space.
Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage
Authors: Jacobsohn Myra K. , Lehman Melanie M. , Jacobsohn Gert M.
Published: November 2006

Pigment leakage from sheep and horse erythrocytes and from red beet tissue induced by non‐polar solvents was determined as a function of pH. The results were compared to disruption of multilamellar vesicles (MLV) composed of phospholipids with equimolar cholesterol under identical conditions of solvent exposure and pH. Solvent access to cholesterol was used to measure vesicle disruption. MLV were made from 1,2‐dioleoyl phosphatidylethanolamine sphingomyelin (SP) and various phosphatidylcholines to simulate the major lipid components of membranes. Pigment leakage from erythrocytes caused by petroleum hydrocarbon (b.p. 60–80°C) was maximal at pH 2–4 and at pH 10, but minimal at pH 6.8; alcohols caused less pigment leakage than petroleum hydrocarbon. Betacyanin leakage from beet tissue induced by petroleum hydrocarbon was maximal at pH 2, with very little leakage at pH 4, 6.6 and pH 10. Alcohols caused minimal damage to beet tissue above pH 2. Cholesterol removal by petroleum hydrocarbon from MLV of mixed lipid composition was maximal at pH 2–4, reduced at pH 6.8 and minimal at pH 10. Lipid mixtures in which fatty acyl side chains of one phospholipid were of a different length than the other lost more sterol than mixtures in which the acyl side chains were of identical chain length. MLV with more than 25% SP lost more sterol than those with less or no SP. Results show that in mixtures of phospholipids, SP exposes the hydrocarbon phase of a bilayer to solvent extraction, a property that was also observed in native membranes. Erythrocyte membranes, which contain SP, were more severely damaged by petroleum hydrocarbon than beet cells, which have none. Membranes from erythrocytes were more prone to solvent disruption at pH 10 than MLV, but they were more resistant at physiological pH. It is suggested that conformational changes in membrane proteins due to shifts in pH cause exposure of hydrophobic portions of surrounding lipids to the environment. At neutral pH, the native conformation of proteins is expected to stabilize the bilayer of membranes.
Evaluation of an oleic acid water‐in‐oil‐in‐water‐type multiple emulsion as potential drug carrierviathe enteral route
Authors: Oba Noriyuki , Sugimura Hisao , Umehara Yasuhiko , Yoshida Masayuki , Kimura Talzo , Yamaguchi Takaji
Published: November 2006

A water‐in‐oil‐in‐water (W/O/W) emulsion composed of oleic acid was used as a carrier of carboxyfluorescein (CF)viathe enteral route, as a model for future drug transport. The absorption of CF in the small intestine of rats given the emulsion (W/O/W group) was compared with the absorption in a group administered CF alone (CF group), and a surface‐active agent in CF solution (MM group). Higher amounts of CF were absorbed in the W/O/W and MM groups than in the CF group. At 120 min, the amount of CF remaining in the intestinal tract was smaller in the MM group than in the W/O/W group. In the early period, CF excretion into bile was higher in the MM group than in the W/O/W group was higher than in the MM group (non‐specific). The blood CF level was significantly higher at 240 and 360 min in the W/O/W group than in the other two groups. The highest concentration in lymph was found in the W/O/W group. The W/O/W emulsion was considered superior to the micelles because it maintained a higher blood level of CF over long periods and transferred it to the lymph. This suggests that the W/O/W emulsion is applicable as a drug carrierviathe enteral route.
Effect of dietary linoleic acid content on the distribution of triacylglycerol molecular species in rat adipose tissue
Authors: Huang Yung‐Sheng , Lin X. , Smith R. S. , Redden P. R. , Jenkins D. K. , Horrobin D. F.
Published: November 2006

The present study examined the effect of varying dietary linoleate intake (0.01, 0.24, 2.4, 24, 80 or 160 g/kg diet) for 24 weeks on the distribution of triacylglycerol (TG) molecular species in rat epididymal adipose tissue. Adipose TG fractions were purified by thin‐layer chromatography and separated into different molecular species by reversephase high‐performance liquid chromatography. The identification of TG species was based on fatty acid composition, retention time and the theoretical carbon number. When the dietary 18∶2n−6 content was equal to or less than 24 g/kg, no significant amounts of n−6 fatty acids (mainly 18∶2n−6) were observed in adipose tissue TG despite the fact that the levels of 20∶4n−6 in liver phospholipids increased significantly. There were 12 major molecular species in adipose tissue when the dietary 18∶2n−6 content was less than 2.4 g/kg. When the diteary 18∶2n−6 content reached 24 g/kg, an additional six TG species containing one, two or three molecules of 18∶2n−6 were observed. The levels of TG molecules containign two or three 18∶2n−6 residues were further increased when the diet contained very large amounts of linoleic acid (160 g/kg). Conversely, those TG species containing only one 18∶2n−6 residue became less abundant. It is suggested that the accumulation of these linoleate‐rich TG molecular species in adipose tissue, particularly di‐ and trilinoleoyl containing TG, is the result of an adequate or an excessive intake of linoleic acid.
Site‐specific differences in the fatty acid composition of human adipose tissue
Authors: Calder P. C. , Harvey D. J. , Pond C. M. , Newsholme E. A.
Published: November 2006

The fatty acid composition of triacylglycerols from fifteen distinct adipose depots taken from each of seven adult male human subjects was compared. Oleic, palmitic, linoleic, stearic, myristic, palmitoleic and vaccenic acids accounted for more than 90% of the triacylglycerol fatty acids in all sites from all subjects; a number of other fatty acids were also identified and quantified. There were large differences in theaverage fatty acid composition between individual subjects. There were no site‐specific differences in the proportions of myristic (3.8–4.7% of triacylglycerol fatty acids), palmitic (23–29%), linoleic (6.7–9.8%) or vaccenic (4.1–4.7%) acids or in the proportions of any of the less abundant fatty acids. There were some significant site‐specific differences in the proportions of palmitoleic, oleic and stearic acids. The calf depot contained more palmitoleic acid (6.41±1.09%) than the trapezius (3.12±0.55%), perirenal (3.59±0.50%) and mesenteric (3.70±0.43%) depots, more oleic acid (42.13±1.27%) than the trapezius (36.03±2.18%), perirenal (36.50±1.56%) and breast (37.13±1.55%) depots and less stearic acid (5.18±0.89%) than the trapezius (8.57±0.97%), perirenal (8.49±0.75%), mesenteric (7.87±0.42%), breast (8.02±0.75%) and clavicular (8.34±0.78%) depots. The buttock depot contained less stearic acid (6.06±0.65%) than the perirenal, mesenteric and clavicular depots, while the anterior thigh depot contained less stearic acid (6.07±0.70%) than the perirenal depot. These findings indicate that, while most human adipose depots differ little in fatty acid composition, some sites, in particular the calf, perirenal, trapezius and mesenteric depots, have site‐specific properties.
Mechanisms of free radical oxidation of unsaturated lipids
Authors: Porter Ned A. , Caldwell Sarah E. , Mills Karen A.
Published: November 2006

The primary producs formed from the autoxidation of lipids can be understood based upon a mechanism that involves five different reaction types. These reactions are: reaction of a carbon radical and molecular oxygen, atom transfer of a hydrogen from substrate to the chain carrying peroxyl, fragmentation of the chain carrying peroxyl to give oxygen and a carbon radical, rearrangement of the peroxyl, and cyclization of the peroxyl. The mechanisms of these primary reaction steps has been the focus of extensive research over the past fifty years, and the current level of understanding of these transformations is the subject of this review.
Cholesteryl ester transfer protein inhibition in hypercholesterolemic hamsters: Kinetics of apoprotein changes
Authors: Zuckerman Steven H. , Evans Glenn F.
Published: November 2006

Inhibition of cholesteryl ester transfer protein (CETP) activity in hypercholesterolemic hamsters results in elevated high‐density lipoprotein (HDL) cholesterol, an increase in HDL size, and the appearance of apolipoprotein E (apo E)‐rich, apo A‐I‐poor particles. The present study has focused on the kinetics of apoprotein redistribution among the HDL particles and the relative increase in HDL‐associated apo E and CETP in hypercholesterolemic hamsters, following inhibition of transfer activity using the monoclonal antibody, TP2. A 60% inhibition in CETP activity was observed 24 h after antibody injection and was associated with an increase in HDL cholesterol and HDL size. Increased amounts of apo E were associated with these HDL particles and remained in this fraction throughout the duration of the study. In contrast, while CETP was also detected on large HDL particles, this distribution shifted back toward the pretreatment pattern by 14 d. The dynamic changes in apoprotein distribution may represent a compensatory physiologic response following disruption of reverse cholesterol transport.
Uptake by macrophages of low‐density lipoprotein damaged by nitrogen dioxide in air
Authors: Kikugawa Kiyomi , Beppu Masatoshi , Okamoto Yutaka
Published: November 2006

In order to know whether nitrogen dioxide, an environmental and endogenous free radical toxin, can participate in the formation of atherosclerotic lesions, damage to low‐density lipoprotein (LDL) by nitrogen dioxide and uptake of the damaged LDL by macrophages were investigated. A solution of LDL at pH 7.5 was exposed to an atmosphere of nitrogen dioxide (70 ppm) in air at 37°C for 5 or 10 h. Lipid oxidation was induced by the exposure as assessed by the formation of thiobarbituric acid reactive substances. Apolipoprotein B was covalently cross‐linked via nondisulfide bonds. Fluorescence analysis showed that tryptophan residues were extensively decreased, and amino acid analysis indicated that the contents of histidine, lysine, and tyrosine residues were decreased by 30–40, 10–20, and 20–30%, respectively. Binding of LDL to thioglycolate‐induced mouse peritoneal macrophages was markedly increased by the exposure as observed by the binding of mouse erythrocytes coated with LDL. The activity of LDL to convert macrophages into lipid‐laden foam cells was also increased by the exposure. Modification of lysine residues of apo B with lipid oxidation products formed by the exposure may be responsible for the uptake by macrophages. The results suggest the possibility that exposure of LDLin vivo to nitrogen dioxide participates in the formation of atherosclerotic lesions.
Antioxidant activity of thiocholesterol on copper‐induced oxidation of low‐density lipoprotein
Authors: Tanaka Mitsuo , Nakagawa Mitsuo
Published: November 2006

The effect of thiocholesterol (SH‐Chol) on the copper‐inducedin vitro oxidation of low‐density lipoprotein (LDL; 1.019<d<1.063) was investigated. Among the antioxidants tested, including cysteine, glutathione, 2‐mercaptoethanol, dithiothreitol, probucol, thiopalmitic acid,. and SH‐Chol, SH‐Chol was the most effective antioxidant in copper‐induced LDL oxidation. Also, SH‐Chol completely inhibited the formation oxysterols i.e., 7‐hydroxycholesterol and 7‐ketocholesterol, in LDL particles and reduced 1,1‐diphenyl‐2‐picrylhydrazyl used as stable free‐radical model. Moreover, SH‐Chol suppressed the degradation of endogenous α‐tocopherol in LDL particles. These findings indicate that SH‐Chol acts as antioxidant in the oxidative damage of LDLin vitro and as a free‐radical scavenger in lipid peroxidation.
Thermotropic behavior of stratum corneum lipids containing a pseudo‐ceramide
Authors: Mizushima Hiromoto , Fukasawa Jun‐ichi , Suzuki Toshiyuki
Published: November 2006

The mechanism of the self‐assembly of the lamellar structure of natural stratum corneum lipids (SCL) has been a subject of considerable interest. We have examined this question by using a synthetic pseudo‐ceramide (sphingolipid E, SLE) which was analogous to the naturally occurring ceramide type 2. The thermotropic properties and the structural characteristics of SLE, together with other main components of SCL, fatty acids, and cholesterol, were investigated by differential scanning calorimetry and X‐ray analysis. A mixture of SLE and stearic acid was in a stable α‐form having a lamellar structure, which is very similar to that of natural SCL. However, lipid mixtures in which stearic acid were replaced by oleic acid did not form lamellar structures, and existed in the crystalline states. This indicates that the stable bilayer formation of the natural SCL is strongly dependent on the molecular fatty acid structure. Moreover, incorporation of cholesterol (0–50%) into equimolar mixtures of SLE/stearic acid and of SLE/oleic acid caused a marked decrease of melting entropies, while the aggregation states of both systems were not changed. This effect of cholesterol can be attributed to the disorder of the molecular packing. These results suggest that the hydrophobic interactions between the SCL are important for bilayer formation as are the hydrophilic interactions between the polar groups.
Monohexosylceramides of larval and adult forms of the tapeworm,spirometra erinacei
Authors: Kawakami Yasushi , Kojima Hisako , Nakamura Kazuo , Suzuki Minoru , Uchida Akihiko , Murata Yoshihiko , Tamai Yoichi
Published: November 2006

The occurrence of glycosphingolipids with unique carbohydrate structures in different species of cestode, Platyhelminth, which had been shown, previously, prompted us to study the molecular species of the monohexosylceramides (cerebrosides) in the pseudophyllidean cestode,Spirometra erinacei. The purpose of the study was to obtain a basis for future investigations of the physiological role of glycolipids in parasitism. Cerebrosides were isolated froms. erinacei at two growth stages, i.e., from the larval form (plerocercoid) and from the adult tapeworms (intestinal form). The cerebrosides were separated into four subfractions by silica gel column chromatography, and their constituents were analyzed by gasliquid chromatography, gas chromatography/mass spectrometry, and high‐performance liquid chromatography/mass spectrometry. The hexoses of the cerebrosides consisted primarily of galactose in both growth stages, while only a small amount of glucose was detected. The ceramides were composed of sphinganine (d18∶0) and phytosphingosine (t18∶0) as sphingoid bases, and of nonhydroxy fatty acids ranging from C16 to C30 and hydroxy stearic acid (18h∶0). The cerebrosides of adult tapeworms contained more 18h∶0 than those of plerocercoids. The combination of hexoses and ceramides in the cerebroside molecules was slightly different in the two growth stages: the glucocerebrosides of plerocercoids contained only d18∶0‐nonhydroxy fatty acids in their ceramide moieties, whereas those of adult tapeworms contained varying ceramide moieties. Our data indicate that the molecular species of glycolipids present were essentially homeostatic throughout growth in spite of the entirely different environmental conditions, although there were slight differences in the hexose distribution in the two growth stages.
The structure of the core polyol of the ether lipids fromSulfolobus acidocaldarius
Authors: Sugai Akihiko , Sakuma Rie , Fukuda Ikuko , Kurosawa Norio , Itoh Yuko H. , Kon Kazuo , Ando Susumu , Itoh Toshihiro
Published: November 2006

The major ether‐type lipid structures ofSulfolobus acidocaldarius (ATCC33909) were composed of caldarchaeol and calditoglycerocaldarchaeol. However, the characterization by nuclear magnetic resonance spectroscopy and mass spectrometry showed that the structure of calditol in calditoglycerocaldarchaeol is not nonitol, 2‐(1′,2′,3′‐trihydroxypropyl)1,2,3,4,5,6‐hexahydroxyhexane, but 2‐hydroxymethyl‐1‐(2,3‐dihydroxypropoxy),2,3,4,5‐cyclopentanetetraol with an ether linkage in the molecule. Such an intermolecular ether linkage was resistant, to BCl3 treatment, but nonresistant to 57% HI degradation treatment conducted at 100°C for 60 h, producting 2‐hydroxymethyl‐1,2,3,4,5‐cyclopentanepentaol from calditol as reaction product. Further, it was confirmed that the structure of calditol is essentially a derivative of glycerol, and hydrocarbon chains were conjugated to the glycerol‐like site in the structure. The calditol with an ether linkage in the molecule suggested an important role regarding the properties of heat‐resistance and acid‐resistance observed inSulfolobales.
Role of cyclic adenosine monophosphate in phospholipid synthesis inMycobacterium smegmatis ATCC 607
Authors: Kaur Harpinder , Khuller G. K.
Published: November 2006

The present study was undertaken to examine the influence of intracellular levels of cyclic AMP on phospholipid synthesis inMycobacterium smegmatis ATCC 607. The cyclic AMP levels were modulated by growing cells in the presence of activator (forskolin) and inhibitor (atropine) of adenylate cyclase, the synthesizing enzyme of cyclic AMP. Forskolin‐grown cells exhibited a 1.4‐fold increase in the level of cAMP while a similar decrease (1.8‐fold) was seen with atropine‐grown cells. These altered levels of cAMP in turn affected the total content, composition and synthesis of phospholipids. Total phospholipid content increased and decreased in cells grown in the presence of forskolin and atropine, respectively. These observations were further supported by alterations in [14C]acetate incorporation as well as in activities of glycerol kinase and glycerol‐3‐phosphate acyltransferase, the key enzymes of phospholipid synthesis. Protein phosphorylation mechanism seems to be involved in phospholipid metabolism as the activities of protein kinase increased and decreased in cells grown in forskolin or atropine cells. Our results demonstrate a correlation between phospholipid synthesis and intracellular levels of cAMP inM. smegmatis.
Purification and properties of an extracellular lipase from the fungusBotrytis cinerea
Authors: Comménil Pascal , Belingheri Lionel , Sancholle Michel , Dehorter Bertrand
Published: November 2006

An extracellular lipase (EC 3.1.1.3) from the fungusBotrytis cinerea has been purified to homogeneity and characterized. The purification included ammonium sulfate fractionation and sequential column chromatography. The purification of the preparation was 31‐fold and recovery yield was 21%. The purified enzyme was associated with esterase activity according to activity staining on polyacrylamide gel. The molecular weight was determined as 60 kDa on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and estimated at 72 kDa using gel filtration, which suggests that the enzyme may be a monomer. The isoelectric point was 6.5, and optimal activity was obtained at 38°C and pH 6.0. This lipase showed a high specificity for synthetic substrates containing long‐chain unsaturated fatty acids using umbelliferone esters. The effect of β‐cyclodextrin on the hydrolysis of olive oil has been studied. The specific activity was 25 μmole/min/mg in the absence of β‐cyclodextrin and 132 μmole/min/mg in its presence.
Fatty acid composition of erythrocyte, platelet, and serum lipids in strict vegans
Authors: Ågren Jyrki J. , Törmälä Marja‐Leena , Nenonen Mikko T. , Hänninen Osmo O.
Published: November 2006

The fatty acid composition of erythrocytes, platelets, and serum lipids was compared between subjects who had been eating a strict uncooked vegan diet (“living food”) for years and omnivore controls. The vegan diet contains equal amounts of fat but more monounsaturated and polyunsaturated and less saturated fatty acids than the mixed diet of the control group. In vegans, the proportion of linoleic acid was greater in all lipid fractions studied. Also, the levels of other n−6 fatty acids were greater, with the exception of arachidonic acid levels, which were similar in most fractions. In erythrocytes, platelets and serum phospholipid fractions, this increase was mainly at the expense of the n−3 fatty acids. The proportions of eicosapentaenoic and docosahexaenoic acid were only 29–36% and 49–52% of those in controls, respectively. In vegans the ratio of n−3 to n−6 fatty acids was only about half that in omnivores. In addition to the lower levels of n−3 fatty acids, the proportions of palmitic and stearic acids were lower in serum cholesteryl esters, triglycerides and free fatty acids of vegans. The proportion of oleic acid was slightly lower only in serum cholesteryl esters and erythrocyte phosphatidylserine. The results show that, in the long term, the vegan diet has little effect on the proportions of oleic and arachidonic acids, whereas the levels of n−3 fatty acids are depressed to very low levels with prolonged consumption of the high linoleic and oleic acid components of this diet.
Characterization of the diacylglycerol acyltransferase activity in the membrane fraction from a fungus
Authors: Kamisaka Yasushi , Yokochi Toshihiro , Nakahara Toro , Suzuki Osamu
Published: November 2006

In an attempt to clarify the mechanism of lipid accumulation inMortierella ramanniana var.angulispora, diacylglycerol acyltransferase (DGAT) in the membrane fraction from this fungus was characterized. The enzyme had an optimum pH of 7.0–7.5, and enzyme activity was blocked by SH‐reagents. Metal ions were not essential for maintaining DGAT activity.n‐Octyl‐β‐d‐glucoside, 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propanesulfonate and Tween 80 were found to preserve activity, while Triton X‐100 and sucrose monolaurate inhibited it. As the inhibition of DGAT activity by Triton X‐100 was overcome by the addition of diacylglycerol (DG), the dependency of DGAT activity on exogenous DG was determined in the presence of 0.1% Triton X‐100. DGAT activity in the membrane fraction was traced in fungi cultured for different time periods or in media at different carbon to nitrogen (C/N) ratios. Although the increase in total lipid content with culture time was accompanied by an increase in DGAT activity, total lipid changes related to changes in C/N ratio did not correlate with DGAT activity. Factors other than DGAT activity in the membrane fraction would appear to be involved in the regulation of total lipid content in this fungus.
Atherosclerosis and plasma and liver lipids in nine inbred strains of mice
Authors: Nishina Patsy M. , Wang Jiajin , Toyofuku Wendy , Kuypers Frans A. , Ishida Brian Y. , Paigen Beverly
Published: November 2006

Nine inbred strains of mice, which are progenitors of recombinant inbred sets, were evaluated for aortic lesion formation and plasma and liver lipid levels. This survey was done to determine if a semi‐synthetic high‐fat diet could elicit the same extent of diet‐induced atherosclerosis as that observed in mice fed a natural ingredient highfat diet and to discover strain‐specific plasma and liver lipid variants for future genetic characterization. Evaluation of aortic lesions after 18 wk of diet consumption showed that strains C57BL/6J, C57L/J, SWR/J and SM/J were susceptible to atherosclerosis and that A/J, AKR/J, C3H/HeJ, DBA/2J and SJL/J were relatively resistant. High‐density lipoprotein cholesterol (HDL‐C) levels were negatively correlated to lesion formation. Susceptible strains had decreased HDL‐C levels when switched from chow to the semi‐synthetic high‐fat, high cholesterol diet, whereas resistant strains either showed no change or a slight increase in HDL‐C levels. The exception to this pattern was found in SM mice, which were susceptible to aortic lesion formation but maintained the same HDL‐C level on both chow and high‐fat diets. HDL size differed among the strains, and levels of plasma apolipoprotein A‐I and A‐II correlated with HDL‐C levels. Liver damage was not correlated to HDL‐C levels or to susceptibility to atherosclerosis. Mice from strain A, which are resistant to atherosclerosis, had evidence of liver damage as observed by elevated levels of plasma alanine aminotransferase activity, by liver histology, by increased liver weight and by exceptionally high hepatic cholesterol content. For all strains, the levels of liver cholesterol and triglycerides were inversely correlated with each other; phospholipids did not vary greatly among strains. No remarkable differences in hepatic fatty acid profile were noted among the strains fed the atherogenic diet, but the fatty acid profile did differ considerably from that found in the diet itself.
The esterification of cholesterol in the yolk sac membrane of the chick embryo
Authors: Shand J. H. , West D. W. , McCartney R. J. , Noble R. C. , Speake B. K.
Published: November 2006

The uptake of lipid from the yolk by the yolk sac membrane of the chick embryo is accompanied by the rapid esterification of a large proportion of the yolk cholesterol. This could arise from enhanced acyl‐CoA:cholesterol acyltransferase (ACAT) activity and/or inhibition of cholesteryl ester hydrolase (CEH) activity. The activity of ACAT was therefore measured in microsomes obtained from yolk sac membranes at various stages of development. A high level of activity (up to 929 pmol of cholesteryl oleate formed per min per mg protein) was found during the second half of this period. Supplementation with exogenous cholesterol stimulated ACAT activity in microsomes obtained from the tissue at the earlier, but not at the later, stages of development suggesting that the enzyme became saturated with microsomal cholesterol as development proceeded. Correlating with this, the concentration of cholesterol in the microsomes increased 4‐fold between 9 and 20 d of development. The activity of CEH was very low in the microsomes and could not be detected in the cytosolic fraction. The activity of a protein, which has been shown to function as an inhibitor of CEH, was found to be present at all stages of development. The high activity of ACAT, together with the low activity of CEH and an active CEH inhibitor protein is a combination well suited to promote an essentially unidirectional conversion of cholesterol to cholesteryl ester. This process may be a major determinant of the rate of lipid transfer from the yolk to the embryo.
Triacylglycerol structure of human colostrum and mature milk
Authors: Martin Jean‐Charles , Bougnoux Philippe , Antoine Jean‐Michel , Lanson Monique , Couet Charles
Published: November 2006

Because triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for thesn‐1 position, palmitic acid for thesn‐2 position and linoleic acid for thesn‐3 position. Linoleic and α‐linolenic acids exhibited the same pattern of distribution and they were both found primarily in thesn‐3 (50%) andsn‐1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in thesn‐2 andsn‐3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.
Dietary saturated, monounsaturated, n−6 and n−3 fatty acids, and cholesterol influence platelet fatty acids in the exclusively formula‐fed piglet
Authors: Innis Sheila M. , Dyer Roger , Wadsworth Louis , Quinlan Paul , Diersen‐Schade Deborah
Published: November 2006

Platelet lipid composition is important to normal platelet morphology and function, and is influenced by dietary fatty acids and cholesterol. The fatty acid composition and cholesterol content of infant formulas differs from those of human milk, but the possible effects on platelet lipids in young infants is not known. This was studied in piglets fed from birth to 18 d of age with one of eight formulas differing in saturated fatty acid chain length, or content of 18∶1, 20∶5n−3 plus 22∶6n−3, or cholesterol. A reference group of piglets fed sow milk was also studied. Sow milk has a fatty acid composition and cholesterol content similar to that of human milk. Piglets fed formulas high in 18∶1 (34.9–40.8% wt fatty acids) and low in 16.0 (≤6.5% wt fatty acids) had lower platelet counts and greater platelet size than piglets fed sow milk (40.4% 18∶1, 30.7% 16∶0). Piglets fed formulas high in 16∶0 (27–29.6%) and 18∶1 (40–40.6%), or low in both 16∶0 (5.9–6.1%) and 18∶1 (10.8–11.2%), had similar platelet counts and size to piglets fed sow milk. Platelet phospholipid % 20∶4n−6 was lower in all the groups of piglets fed formula than in the group fed sow milk. Addition of fish oil with 20∶5n−3 plus 22∶6n−3 to the formula further decreased platelet phospholipid 20∶4n−6. Addition of cholesterol to the formula increased the platelet phospholipid % 20∶4n−6 and platelet volume.