bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of vitamins A and E in blood and liver of rats depleted of vitamin A or vitamin E
Authors: Omaye Stanley T. , Chow Faye I.
Published: November 2006

Young Sprague‐Dawley male rats (n=150) were fed a semipurified diet, either without vitamin A (VA), without vitamin E (VE) or supplemented with both vitamins A and E (control). At the end of weeks 0, 1, 3, 5, 6, 7, 8 and 9, groups of rats were anesthetized with methoxyflurane, and blood was collected by cardiac puncture until the rat was exsanguinated. The liver was excised. Whole blood (WB_ from each rat was fractionated into plasma (PLA), leukocytes (LEU), platelets (PLT) and erythrocytes (RBC). Each blood components was extracted with hepatane and livers were extracted with CHCl3/CH3OH (2∶1, v/v). The extracts were analyzed for VA and VE by high performance liquid chromatography. The relationship among blood components in the loss of VA was PLT=LEU>WB>PLA. The relationship among blood components in the loss of VE was PLA>RBC>WB>LEU‐PLT. VA and VE levels in other blood components decreased precipitously between weeks 0 and 4 in the animals placed on deficient diets. These results and correlation analyses between vitamin contents of blood components and of livers indicate inadequacies for the use of certain blood components as monitors of lipid‐soluble vitamin status in the rat.
Identification of 5,9‐hexadecadienoic acid in the marine spongeChondrilla nucula
Authors: Carballeira Nestor M. , Maldonado Lilliam
Published: November 2006

The fatty acid 5,9‐hexadecadienoic was identified in the spongeChondrilla nucula. This is the shortest fatty acid with the Δ5,9 unsaturation yet isolated from a marine sponge.
Mammary tumorigenesis in rats fed diets high in lard
Authors: Rogers A. E. , Conner B. , Boulanger C. , Lee S.
Published: November 2006

Studies were performed to examine the effect of a lard diet on tumorigenesis by 7,12‐dimethylbenzanthracene (DMBA), given parenterally rather than by gavage, to eliminate any effect of the high lard diet on carcinogen absorption. In addition, the effect of low dietary levels of the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in the tumor model was evaluated. The lards fed were analyzed for fatty acid composition and content of certain potential contaminants. DMBA induced tumors when given by intravenous or subcutaneous injection. The high lard diet appeared to enhance tumorigenesis in rats given a dose of 0.25 mg (10% of the gavage dose) by injection into the mammary gland, although the effect was not statistically significant. In other experiments using lard from different sources and DMBA given by gavage, significant enhancement of tumorigenesis was limited to groups fed the high lard diets throughout the experiment or beginning after DMBA exposure. In contrast to earlier results, there was no demonstrable effect of feeding the high lard diets before DMBA administration. Addition of BHA and BHT to the lard at the concentration assayed in commercial lard samples or at the maximum concentration permitted did not influence the tumorigenesis. In groups in which tumorigenesis was enhanced by the high lard diet, the incidence of malignant, invasive tumors was higher than in other groups.
Effect of dietary components on the pathobiology of colonic epithelium: Possible relationship with colon tumorigenesis
Authors: Bird R. P.
Published: November 2006

The concept that diet plays an important role in the initiation and/or development of various types of tumors in man and experimental animals is well documented. The etiology of colon cancer is complex and multifactorial in nature, and these is little information on the dietary components that may act as initiators during colon tumorigenesis. We have evaluated various dietary heterocyclic mutagenic amines present in a typical “Western” diet for their nuclear damaging effect (presumably a genotoxic response) on the colonic epithelium of C57BL/6J mice in vivo. Among the mutagenic amines studied, 2‐amino‐3,4‐dimethylimidazo(4,5‐f)quinoline and 2‐amino‐3‐methylimidazo(4,5‐f)quinoline were very potent inducers of nuclear aberrations. These observations provide us with clues that our daily diet may contain colon‐specific genotoxic components. Promotional effects of dietary fat and/or bile acids on colon tumorigenesis have been well studied. Dietary levels of calcium (0.1, 0.5 or 1.0% by weight) appear to modify the toxicity of orally administered fat or cholic acid (assessed by quantifying cell proliferation). The colons of animals consuming 0.1% or 0.5% calcium diet were more susceptible to the toxicity, whereas the colons of those consuming a 1.0% calcium diet appeared more like control colons. These studies demonstrate a profound effect of dietary constituents on the pathobiology of the colonic epithelium which may have a marked influence on the colon tumorigenesis.
A comparison of lipids from liver and hepatoma subcellular membranes
Authors: Wood Randall , Upreti Girish C. , de Antueno Roberto J.
Published: November 2006

Subcellular fractions of nuclei, mitochondria, endoplasmic reticulum, plasma membrane and cytosol were prepared from liver and hepatoma 72288CTC. Marker enzyme activities, biochemical compositions and electron microscopy were used to establish purity. Hepatoma NADH: cytochrome C reductase and 5′‐nucleotidase exhibited abnormal subcellular distributions.

The lipids from the subcellular fractions were examined in detail. Mitochondria and plasma membranes were characterized by elevated percentages of diphosphatidylglycrerol and sphingomyelin, respectively, in both tissues. All hepatoma subcellular fractions contained dramatically elevated levels of sphingomyelin and cholesterol, two components that form preferential strong complexes in vitro. The fatty acid composition of hepatoma sphingomyelin differed markedlg from liver and, unlike liver, did not exhibit organelle specific compositions. Some hepatoma lipid classes contained reduced percentages of palmitate while others contained higher levels. Hepatoma phosphatidylcholine and phosphatidylethanolamine from organelles contained lower percentages of long chain polyunsaturated fatty acids than liver. Generally, unique fatty acid profiles exhibited by individual phospholipid classes of liver subcellular fractions were absent or much reduced in the hepatoma. The ratios of oleate to vaccenate were near one for most of the phospholipid classes of most liver fractions, but all hepatoma classes, with few exceptions, contained a much higher percentage of oleate in all subcellular fractions. The hypothesis is proposed that the origin of some acyl moieties for the biosynthesis of various hepatome lipid classes differs from liver sources. The possible changes in acyl pools, sources and compartments for complex lipid biosynthesis could result in change in the quantities of molecular species that could contribute to the abnormal properties of the hepatoma membranes.
Molecular species composition of the major diacyl glycerophospholipids from muscle, liver, retina and brain of cod (Gadus morhua)
Authors: Bell M. V. , Dick J. R.
Published: November 2006

The molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from white muscle, liver, retina and brain of cod (Gadus morhua) were determined by high‐performance liquid chromatography of the respective 1,2‐diacylglycerol 3,5‐dinitrobenzoyl derivatives. A minimum of 69 diacyl species was identified. In muscle and liver saturated fatty acid/polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid/PUFA molecular species were predominant, particularly 16∶0/20∶5 and 16∶0/22∶6 in PC, 16∶0/22∶6 and 18∶1/22∶6 in PE and 18∶0/22∶6 and 18∶1/22∶6 in PS. Didocosahexaenoyl species were major components of PC, PE and PS from retina, comprising 29.3, 71.8 and 59.7% of the respective totals. Didocosahexaenoyl species were also abundant in PE and PS from brain, accounting for 13.8 and 24.0% of the totals, respectively. DiPUFA species were important in muscle, totalling 21.2% in PC and 38.3% in PE. PC from all tissues had the largest amounts of species containing only saturated or monounsaturated fatty acids, accounting for 59.8% of PC from brain, including 12.8% of 18∶1/24∶1 plus 24∶1/18∶1.
Diacetone‐D‐glucosyl‐3‐O‐(N,N‐diethylamido)‐thiophosphates of the lipid‐soluble vitamins D2, D3 and E
Authors: Stamatov Stephan D. , Gronowitz Salo
Published: November 2006

The acyclic triamides of phosphorous acid, after appropriate activation, offer a number of advantages over conventional reagents when biologically active lipids are to be phosphorylated. The hexaethyltriamide of phosphorous acid activated by addition of iodine at the optimum molar ratio of 1.05∶0.05 was used as phosphorylating reagent to synthesize diacetone‐D‐glucosyl‐3‐0‐(N,N‐diethylamido)thiophosphates of ergocalciferol, cholecalciferol and DL‐α‐tocopherol in a “one‐pot” procedure in overall yields of 83–87%. The high selectivity of the phosphorylation at the monoester formation stage permits the direct synthesis of asymmetrical diesters. Anisochronicity was detected in the13C and31P nuclear magnetic resonance spectra of the thiophosphates synthesized. The compounds represent new types of glycophospholipid structures which, in addition to carbohydrate and a phosphagen fragment, contain a lipid‐soluble vitamin.
Sterol biosynthesis inhibitors: Their current status and modes of action
Authors: Mercer E. I.
Published: November 2006

The mechanism of each of the reactions in the post‐squalene segment of the fungal and higher plant sterol biosynthetic pathway is outlined. The inhibitors of the enzymes catalyzing the reactions are described and how inhibition is brought about is explained in the areas where it is known.
Involvement of heme components in sterol metabolism ofSaccharomyces cerevisiae
Authors: Lorenz R. Todd , Parks L. W.
Published: November 2006

There is an intimate association between sterol biosynthesis in yeast and aerobicity. Besides the requirement for molecular oxygen for the epoxidation of squalene, cytochrome hemoproteins are involved in demethylation and desaturation steps. Regulatory effects of hemes on sterol formation have been demonstrated using specifically defective mutants of yeast. Heme competency participates in a mechanism whereby wild‐type cells are prevented from taking exogenous sterols from the growth media. The multiple interactions of hemes and sterols appear to be associated with the variously defined functions for sterols in the yeast cells.
Free and combined sterols ofPavlova gyrans
Authors: Gladu Patricia K. , Patterson Glenn W. , Wikfors Gary H. , Lusby William R.
Published: November 2006

Pavlova gyrans, a unicellular alga of interest as food for oysters, was cultured axenically and examined for sterol composition. Desmethyl monohydroxy sterols, which are frequently seen in algae, made up 40% of the total sterols and were observed primarily in the free sterol fraction. The principal sterols of this group were 5‐ergostenol, poriferasterol, and clionasterol, as well as some poriferast‐22‐enol and poriferastanol. Several “methyl” sterols with unusual structures made up 27% of the total sterols. The principal “methyl sterols” were 4α‐methyl ergostanol, 4α‐methyl poriferastanol, and 4α‐methyl poriferast‐22‐enol. Methyl sterols were found primarily in the ester fraction. Also observed was a new class of dihydroxysterols composing 33% of the total sterols. These sterols are structurally related to the methyl and desmethyl sterols ofPavlova but contain an extra nuclear hydroxyl which can be acetylated when present on a desmethyl sterol, but which is nonreactive with acetic anhydride in 4α‐methyl sterols. None of these sterols were observed in ester form but are concentrated in the acid‐hydrolyzable, bound fraction. The unique nature of these sterols suggests potential taxonomic utility.
Sterols ofKalanchoe pinnata: First report of the isolation of both C‐24 epimers of 24‐alkyl‐Δ25‐sterols from a higher plant
Authors: Akihisa Toshihiro , Kokke W. C. M. C. , Tamura Toshitake , Matsumoto Taro
Published: November 2006

Eighteen sterols were isolated from the aerial parts ofKalanchoe pinnata (Crassulaceae) including four novel sterols,viz. (24R)‐stigmasta‐5,25‐dien‐3β‐ol (24‐epiclerosterol), (24R)‐5α‐stigmasta‐7,25‐dien‐3β‐ol, 5α‐stigmast‐24‐en‐3β‐ol, and 25‐methyl‐5α‐ergost‐24(28)‐en‐3β‐ol. 24‐Epiclerosterol and its Δ7‐analog occur together with their 24S/β‐epimers in the same plant making this the first report of the isolation of both C‐24 epimers of Δ25‐unsaturated 24‐alkylsterols from a non‐marine organism. Iodine‐catalyzed isomerization of stigmasta‐5,24‐dien‐3β‐ol (24‐ethyldesmosterol), the main sterol ofK. pinnata, yielded 24‐epiclerosterol among other products.
Occurrence and levels of ecdysteroids in spinach
Authors: Grebenok Robert J. , Ripa Perry V. , Adler John H.
Published: November 2006

The dominant ecdysteroid in spinach,Spinacia oleracea L., is 20‐hydroxyecdysone (2β,3β,14α, 20R,22R,25‐hexahydroxy‐5β‐cholest‐7‐en‐6‐one) with the presence of a smaller amount of polypodine B (2β,3β,5β,14α,20R,22R,25‐heptahydroxycholest‐7‐en‐6‐one). Ecdysteroids are present in the seed embryo at 14 μg ecdysteroid/seed, and ecdysteroid levels increase, in the plant during growth and development. During the onset of ecdysteroid production, the ratio of ecdysteroid to total sterol shifts from a value of one to about ten over the course of a week. Spinach may serve as a model to study ecdysteroid biosynthesis in plants.
Intake of different eicosapentaenoic acid‐containing lipids and fatty acid pattern of plasma lipids in the rats
Authors: Hamazaki Tomohito , Urakaze Masaharu , Makuta Masahiro , Ozawa Akio , Soda Yasuji , Tatsumi Hiroshi , Yano Saburo , Kumagai Akira
Published: November 2006

The ethyl ester of eicosapentaenoic acid (EPA) is the only pure EPA‐containing lipid available in bulk for oral administration. However, there is doubt as to whether EPA ethyl ester can efficiently increase the plasma levels of EPA in comparison with the ability of other kinds of EPA‐containing lipids to do so. Therefore, two other kinds of EPA‐containing lipids were prepared to study the efficiency of oral administration of those lipids for increasing the EPA content in plasma phospholipids and cholesteryl esters. EPA‐containing lipids which were investigated were [A], 1,2,3‐trieicosapentaenoyl‐glycerol, [B] 2‐eicosapentaenoyl‐phosphatidylcholine and [C] ethyl ester of EPA. An adjusted amount of lipids [A], [B] and [C] was administered to rats through a gastric tube for 4 days (the first experiment) or for 10 days (the second experiment), and the fatty acid composition of plasma phospholipids and cholesteryl esters was determined. In the first experiment, there were no significant differences in the efficiency for increasing EPA levels in either phospholipids or cholesteryl esters among the lipids. In the second experiment, the EPA levels of both plasma phospholipids and cholesteryl esters of rats administered ethyl ester of EPA were significantly higher than those of rats administered 2‐eicosapentaenoyl‐phosphatidylcholine. The EPA levels of the rats administered 1,2,3‐trieicosapentaenoylglycerol were between the levels of the two groups mentioned above, but the differences in the EPA levels were not significant. Although an ethyl ester‐type molecule is not a naturally occurring lipid, ethyl ester of EPA is equal to 1,2,3‐trieicosapentaenoyl‐glycerol and appears to be superior to 2‐eicosapentaenoyl‐phosphatidylcholine as to the efficiency for increasing EPA levels in total plasma phospholipids and plasma cholesteryl esters.
L‐carnitine effect on plasma lipoproteins of hyperlipidemic fat‐loaded rats
Authors: Maccari F. , Arseni A. , Chiodi P. , Ramacci M. T. , Angelucci L. , Hulsmann W. C.
Published: November 2006

The effect of oral L‐carnitine administration to rats fed olive oil has been studied. Carnitine significantly decreased triglyceride, cholesterol and phospholipid levels. Particularly, the levels of chylomicron and very low density lipoproteins in the blood were lowered. Low density lipoprotein levels were not affected, and high density lipoproteins were found to be decreased by 20%. Because carnitine did not change the composition of chylomicron and very low density lipoproteins fraction or affect the gastrointestinal triglyceride residue (about 1/3 of the original load), an effect of carnitine on hepatic fatty acid handling is most likely. The lowering of plasma free fatty acid levels by carnitine administration is in favor of an effect of carnitine on fatty acid handling. The effect on the liver is illustrated by the study of acetoacetate formation in in vitro perfused livers from previously olive oil loaded±carnitine‐treated rats. Carnitine pretreatment stimulated ketogenesis. It is speculated that carnitine administration, by promoting β‐oxidation, lowers the production of very low density lipoproteins. This may be accomplished partly by an increase in the hepatic level of fatty acid binding protein, which also has been observed.
Polyunsaturated fatty acids in tissues of rats fed trielaidin and high or low levels of linolenic acid
Authors: Astorg Pierre‐Olivier , Chevalier Joëlle
Published: November 2006

Male and female weanling rats that were born to dams fed a diet low in linolenic acid received diets of 15% lipids by weight containing 45% elaidic acid (as trielaidin) and 8.5% or 0.1% linolenic acid for 10 weeks. Four other groups, in which palmitic or oleic acid replaced elaidic acid in the diet, served as controls. The fatty acid profiles of several lipid classes were determined in adipose tissue, adrenals, testes, heart and brain. Elaidic acid was incorporated into tissue lipids in varying degrees, depending on the organ and on the lipid class. Feeding elaidic acid induced no changes in the polyunsaturated fatty acid (PUFA) profiles of testes lipids but resulted in definite modifications of the PUFA patterns of heart phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In linolenic acid‐deprived rats, arachidonic acid was decreased in PC and linoleic acid was increased in both PC and PE; 22∶5n−6 was strongly depressed in both PC and PE. In linolenic acid‐fed rats, 22∶6n−3 was decreased in PC and PE. These changes, on the whole, were more evident in females, and some also were observed in adrenal cholesteryl esters but only slightly in brain phospholipids. the apparent inhibition of the biosynthesis of PUFA induced by dietary elaidic acid appeared to be complex and of greater intensity in the n−6 fatty acid series than in their n−3 homologues.
Effect of marginal zinc deficiency on the apolipoprotein‐B content and size of mesenteric lymph chylomicrons in adult rats
Authors: Koo Sung I. , Lee Christine C. , Norvell John E.
Published: November 2006

To investigate the mechanisms underlining the impaired intestinal absorption of lipids in zinc deficiency, the apo‐B content and chemical composition of chylomicrons from marginally zinc‐deficient rats fed 2.8 ppm of dietary zinc (ZD) were compared with those from pair‐fed (PF) and ad libitum control (CT) groups fed an adequate level (30.8 ppm) of zinc. Chylomicrons, obtained by cannulating the mesenteric lymph, were isolated by ultracentrifugation at 1.3×106 g/min at 12 C and purified by 2% agarose column chromatography. Apolipoprotein‐ (apo) B was separated by the method of isopropanol precipitation. The apo‐B concentration of chylomicrons was lowered significantly in ZD group. The apo‐B contents of chylomicrons in ZD, PF and CT rats, as expressed as % chylomicron protein, were 8.7±0.1, 11.5±0.5 and 10.7±0.7%, respectively. No significant differences were noted between ZD and PF groups in total protein (TP), phospholipid (PL), triglyceride (TG) and cholesterol (CH), although there was a slight decrease in TG and an increase in CH in CT rats compared with ZD and PF groups. The ratio of the core to surface constituents, as determined by TG/(TP+PL), was significantly higher in ZD group relative to the controls, suggesting that chylomicrons from ZD rats were larger. This finding was consistent with the appearance of larger chylomicron particles in the lacteal of the intestinal mucosa following lipid ingestion. These findings suggest that the intestinal synthesis of apo‐B may be defective in zinc‐deficient rats and may explain in part the impaired absorption of dietary lipids observed in zinc deficiency.
Extraction and quantitation of total cholesterol, dolichol and dolichyl phosphate from mammalian liver
Authors: Crick Dean C. , Carroll Kenneth K.
Published: November 2006

A procedure is described for the determination of total cholesterol, dolichol and dolichyl phosphate (Dol‐P) in mammalian liver. It is based on extraction of these compounds into diethyl ether after alkaline saponification of the tissue. Extractability is affected by the length of saponification and concentration of potassium hydroxide (KOH) in the saponification mixture. After extraction, total cholesterol and dolichol are quantitated directly by reverse‐phase high pressure liquid chromatography (HPLC) on C18. Dol‐P requires further purification before quantitation by HPLC, this is accomplished by chromatography on silicic acid. These methods gave recoveries of over 90% for cholesterol and dolichol and about 60% for Dol‐P, using [4‐14C]cholesterol, a polyprenol containing 15 isoprene units, and [1‐14C]Dol‐P as recovery standards. Concentrations of total cholesterol, dolichol and Dol‐P in livers from one month‐old‐CBA mice were found to be 5.7±0.7 mg/g, 66.3±1.2 μg/g and 3.7±0.3 μg/g, respectively.
Analysis of disteryl ethers
Authors: Schulte Erhard , Weber Nikolaus
Published: November 2006

Disteryl ethers isolated from a vegetable oil and a table margarine were analyzed by capillary gas chromatography. The composition of disteryl ethers in such products reveals whether vegetable oils are mixed with animal fats and if these materials have been subjected to in dustrial bleaching
Effects of eicosatetraynoic acid on membrane lipids of trout liver and intestine
Authors: Pelletier X. , Leray C.
Published: November 2006

After two months feeding either an (n‐3) or an (n‐6) fatty acid‐rich diet, two groups of trout were switched to the (n‐6) or the (n‐3) fatty acid‐rich diet, respectively. Half of each group was treated with 0.03% 5,8,11,14‐eicosatetraynoic acid (ETYA) in the diet. Liver and intestinal brush border membrane lipids were analyzed. No effect was observed on their cholesterol content. ETYA induced an accumulation of 18∶2(n‐6), and it did not affect the 20∶4(n‐6) content but decreased the 22∶5(n‐6) content. ETYA induced an increase of 18∶3(n‐3) content in the brush border membrane and a decrease of the 22∶6(n‐3) content in the liver. Those results suggest that ETYA blocks mainly the Δ6‐desaturase, which should have two different sites in the liver and one in the intestine.
The filamentous fungusmortierella alpina, high in arachidonic acid
Authors: Totani Nagao , Oba Kenkichi
Published: November 2006

Arachidonic acid is not available readily, although it is widely distributed in animal tissue. We found that in some strains ofMortierella alpina, arachidonic acid accounted for 68.5–78.8% of the total fatty acids. This is more than twice the arachidonic acid content of any organism previously reported. The content of arachidonic acid per dry cell weight was about 25%. Our findings offer a method for the efficient isolation of arachidonic acid in large amounts.
Effect of ethanol on platelet phospholipase A2
Authors: Stubbs Christopher D. , Rubin Raphael
Published: November 2006

Platelet aggregation is known to be inhibited by ethanol, and this has been suggested to be one of the attenuating effects of ethanol in cardiovascular disease. Recent studies have implicated an inhibition of phospholipase A2 induced arachidonic acid release, since the production of prostanoids that are formed from arachidonic acid and are involved in the aggregation process has been shown to be diminished by ethanol. Phospholipase A2 is found in platelets in both a cytosolic form, from where it may translocate to the plasma membrane to release arachidonic acid, and in a secretory form which is released extracellularly upon activition. In the present study, the effect of ethanol on the secretion of phospholipase A2 and on its activity was determined. It was found that ethanol inhibited trast, the activity of the cytosolic form of phospholipase A2 was inhibited by ethanol.
Effects of dietary n−3 fatty acid‐enriched chicken eggs on plasma and tissue cholesterol and fatty acid composition of rats
Authors: Jiang Zhirong , Sim Jeong S.
Published: November 2006

The purpose of this study was to examine the effects of feeding n−3 polyunsaturated fatty acid (PUFA)‐enriched chicken eggs on plasma and liver cholesterol levels and fatty acid composition in rats. Eggs were collected from laying hens fed diets containing 10% flax seed (Hn−3), 12% sunflower seed (Hn−6), or wheat and soybean meal control (CON). Yolk powders were prepared and fed at the 15% level to weanling female Sprague‐Dawley rats for 28 days. Consumption of n−3 PUFA‐enriched yolks significantly reduced both plasma and liver total cholesterol. Liver total lipids and phospholipids of rats fed Hn−3 diet were enriched with linolenic, eicosapentaenoic, and docosahexaenoic acids with a concomitant reduction of arachidonic acid in liver phospholipids. The plasma cholesterol of rats fed yolk powders enriched with n−6 PUFA (mainly linoleic acid) was reduced to the same extent as in those fed the n−3 enriched, but the liver cholesterol was significantly increased, indicating differential effects of dietary n−3 and n−6 PUFA. The results demonstrated that the cholesterolemic and tissue lipid modulating properties of chicken eggs could be modified in a favorable way by altering the fatty acid composition of yolk lipids through manipulation of laying hen diets.
An extended method for separating and quantitating molecular species of phospholipids
Authors: Wiley Margaret G. , Przetakiewicz Marek , Takahashi Mareyuki , Lowenstein John M.
Published: November 2006

AN improved and extended method for separating and quantitating molecular species of four phospholipid classes is presented. Crude lipid extract is first separated into phospholipid classes on a silica column. Each phospholipid class is then separated into molecular species without derivatization using high‐performance liquid chromatography on columns packed with octadecyl silica. Quantitation of individual species is achieved by measuring absorbance at 205 nm. Factors for converting absorbancies to mol fractions have been determined. Quantitation by absorbance at 205 nm agrees well with quantitation by gas chromatography which is preferred to quantitation by phosphate analysis. One hundred phospholipid species have been identified. A table of relative retention times of molecular species is provided. Examples of quantitative analyses of species composition are presented.
Incorporation of lipids labeled with various fatty acids into the cytoskeleton of aggregating platelets
Authors: Packham M. A. , Guccione M. A. , Bryant N. L. , Livne A.
Published: November 2006

Earlier studies showed that during the first 20 to 25 seconds of aggregation induced by thrombin (0.1 U/mL) or adenosine diphosphate (ADP) (2μM) of rabbit or human platelets prelabeled with [3H]palmitic acid, labeled lipid became associated with the cytoskeleton (isolated after lysis with 1% Triton X‐100, 5 mM EGTA [ethylene glycol‐bis‐(β‐aminoethyl ether(N,N,N′,N′‐tetraacetic acid] in the presence of 0.5 mM leupeptin and 50 mM benzamidine). In comparison with labeled lipid in intact platelets, the labeled lipid that was associated with the cytoskeleton was enriched in phospholipids and ceramide. To determine whether these effects were specific for lipids labeled with palmitic acid, we studied rabbit platelets in which lipids had been labeled by incubation of the platelets with pairs of14C‐ or3H‐labeled palmitic, stearic, arachidonic, and linoleic acids. Examination of the distribution of label among the lipid classes of intact platelets showed that phospholipids contained most of the label. Under the conditions of limited, thrombin‐induced aggregation used, labeled lipids were not lost from the platelets and the distribution of label among the lipid classes was essentially unchanged. There were major differences in the incorporation of labeled lipids into the cytoskeleton. The greatest incorporation (2.1 to 2.8% of the label in the platelets) was observed with palmitic acid‐labeled lipids; by direct comparison, only 44% as much of the label of stearic acid‐labeled lipids, 21% as much of the label of linoleic acid‐labeled lipids, and only 6% as much of the label of arachidonic acid‐labeled lipids was incorporated into the cytoskeleton. Thus the pool of phospholipid that is readily labeled with arachidonic acid appears to be selectively excluded from the cytoskeleton. Also noteworthy is the 4‐ to 5‐fold enrichment of the cytoskeleton with labeled ceramide; an average of 16% of the label from stearic acid in the cytoskeleton was in ceramide. We suggest that ceramide and phospholipids that are readily labeled with saturated fatty acids are selectively incorporated into the cytoskeleton during the early stages of aggregation and may be specifically associated with the points of contact between platelets.
Effect of acylation stimulating protein on the triacylglycerol synthetic pathway of human adipose tissue
Authors: Yasruel Zivart , Cianflone Katherine , Sniderman Allan D. , Rosenbloom Mark , Walsh Mark , Rodriguez Miguel A.
Published: November 2006

Acylation stimulating protein (ASP) is a 14 kDa plasma protein which causesin vitro triacylglycerol synthesis in human adipocytes and fibroblasts to increase substantially. ASP was found to stimulate human adipose tissue microsomal glycerophosphate acyltransferase and diacylglycerol acyltransferase activities by 23% and 90%, respectively. However, phosphatidate phosphohydrolase activity showed no increase in activity, nor did microsomal acyl‐CoA synthetase activity. Moreover, ASP did not decrease the apparent Km of diacylglycerol acyltransferase (DGAT), but rather increased its apparent Vmax suggesting direct interaction of ASP with DGAT.
Alterations of hepatic acetyl‐CoA carboxylase by 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin
Authors: McKim J. M. , Marien K. , Schaup H. W. , Selivonchick D. P.
Published: November 2006

The effect of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) on acetyl‐CoA carboxylase (ACC) activity and synthesis was examined. Male Wistar rats received a singlei. p. injection of TCDD (53 μg/kg), and nine days later body weight, liver weight, hepatic lipid, ACC activity and mass were determined and compared to pair‐fed controls. Body weights of TCDD‐treated animals decreased, while liver weights increased resulting in an increase in liver to body weight ratios. ACC activity was decreased by 65%, however sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and Western analysis using a biotin specific probe revealed that ACC protein levels were not appreciably changed. In addition, there was a large increase in exogenous lipid material in TCDD‐treated livers as determined by osmium tetroxide staining. These data suggest that the decrease in ACC activity may be due to direct inhibition of the enzyme by negative allosteric interactions with free fatty acids released from adipose tissue that subsequently accumulate in liver.
Steryl esters in a cell suspension culture of celery (Apium graveolens)
Authors: Dyas Lynne , Prescott Mark C. , Evershed Richard P. , Goad L. John
Published: November 2006

Arange of analytical techniques was used to investigate the composition of the steryl fatty acyl esters in a cell suspension culture of celery (Apium graveolens). Gas chromatography (GC) and GC‐mass spectrometry (GC‐MS), using electron ionization (EI) and negative ion chemical ionization (NICI), were employed to characterize the intact steryl esters. Assignments were supported by analysis of the sterol and fatty acid moieties released from the intact molecular species by alkaline hydrolysis. A selectivity for sterol esterification was noted, with the major free sterol, stigmasterol, occurring only in a very small amount in the esterified form. Instead, the precursors to Δ5‐phytosterols, particularly cycloartenol, predominated in the ester fraction. The pentacyclic triterpene, β‐amyrin, was also found as the palmitate and linoleate esters. Changes in composition and abundance of the steryl esters during the different growth phases of a celery cell suspension culture were investigated. The total amount of esterified sterols exceeded that of free sterols throughout the growth cycle. The changes observed during growth highlighted differences between the esters of precursor sterols and those of the 4‐desmethyl‐sterols, and it is postulated that the various steryl esters perform different functions in cell metabolism.
Stereospecific analysis of triacyl‐sn‐glycerols by chiral high‐performance liquid chromatography
Authors: Takagi Toru , Ando Yasuhiro
Published: November 2006

A method for the stereospecific analysis of triacyl‐sn‐glycerols by high‐performance liquid chromatography (HPLC) on a chiral column is described. Triacyl‐sn‐glycerols were partially degraded with ethyl magnesium bromide, and the monoacylglycerols produced were separated as 1‐ and 2‐monoacylglycerol fractions by thin‐layer chromatography on boric acid‐impregnated silica gel plates. The 1‐monoacylglycerols were resolved intosn‐1 andsn‐3 monoacylglycerol fractions by HPLC on a chiral column (Sumichiral OA‐4100) after derivatization with 3,5‐dinitrophenyl isocyanate. Fatty acid methyl esters obtained from the original triacyl‐sn‐glycerols, 1‐ and 2‐monoacylglycerol fractions, andsn‐1 andsn‐3 monoacylglycerol fractions were analyzed by gas chromatography on open‐tubular columns. Stereospecific acyl distributions in triacyl‐sn‐glycerols were calculated from the data. The acyl distributions of several oils were obtained. The method is rapid, simple and gave reproducible results.
4‐Desmethylsterols from the marine bivalveMacoma balthica
Authors: Jarzebski Andrzej
Published: November 2006

4‐Desmethylsterols fromMacoma balthica L. were investigated by gas chromatography and gas chromatography/mass spectrometry after isolation by argentation and column chromatography. Twenty‐three Δ0‐ and Δ5‐sterols with saturated and unsaturated side chains were identified. It is suggested that sterols inM. balthica are derived from dietary sources. The great diversity of minor 4‐desmethylsterols is likely to be due to their role as intermediates in the metabolism of dietary sterols.
Multiple forms of the enzyme glycerophosphodiesterase are present in human brain
Authors: Ross Brian M. , Sherwin Allan L. , Kish Stephen J.
Published: November 2006

Brain levels of glycerophosphodiesters, including glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE), are altered in many human central nervous system disorders. Although much information is available on the enzymes responsible for the formation of these phospholipid metabolites, little information is known regarding their catabolism, by glycerophosphodiesterases, in human brain. In both autopsied and biopsied temporal cortex, a phosphocholine‐producing lycerophosphodiesterase activity was observed. In the presence of 1 mM EDTA, the enzyme possessed a pH optimum of 9.0, while the addition of 5 mM zinc acetate shifted the pH optimum to 10.5. When assayed at pH 9.0 in the absence of zinc acetate, the Km and Vmax were 104±2 μM and 77±18 nmol/h/mg protein, respectively, while assaying at pH 10.5 in the presence of 5 mM zinc acetate yielded a Km of 964±56 μM, and a Vmax of 534±114 nmol/h/mg protein. Furthermore, whereas submillimolar concentrations of zinc acetate stimulated the activity of the enzyme in a dose‐dependent manner when assayed at pH 10.5 (EC50=20.3±3.0 μM), this did not result in a reciprocal inhibition of glycerophosphocholine phosphodiesterase (GPC PD) activity when assayed at a more acidic pH. This may suggest that human brain contains two phosphocholine‐producing GPC PD activities, differentiable by their sensitivity to zinc ions. An activity capable of hydrolyzing GPE to form phosphoethanolamine could not be detected in either biopsied or autopsied brain. However, a choline/ethanolamine‐producing glycerophosphodiesterase activity could be readily detected in biopsied, but not autopsied brain. This novel enzyme possessed a neutral pH optimum and was dependent upon divalent cations for activity. In conclusion, human brain contains at least two different glycerophosphodiesterases, a phosphocholine, and a choline/ethanolamine‐producing activity, only one of which can be detected in autopsied tissue. The results of previous studies measuring brain glycerophosphodiesterase activity in degenerative brain conditions may need to be reevaluated in the light of these observations.
Regulation of cholesterol synthesis in four colonic adenocarcinoma cell lines
Authors: Cerda Sonia R. , Wilkinson John , Broitman Selwyn A.
Published: November 2006

Colon tumor cells, unlike normal human fibroblasts, exhibited an uncoupling of low density lipoprotein (LDL)‐derived cholesterol from cellular growth, when endogenous cholesterol synthesis was inhibited by mevinolin, a hydroxymethylglutaryl‐CoA reductase (HMG‐CoAR) competitive inhibitor [Fabricant, M., and Broitman, S.A. (1990)Cancer Res. 50, 632–636]. Further evaluation of cholesterol metabolism was conducted in two undifferentiated (SW480, SW1417) and two differentiated (HT29, CACO2) colonic adenocarcinoma (adeno‐CA) cell lines and an untransformed human fibroblast, AG1519A. Cells grown in monolayer culture to near subconfluency were used to assess endogenous cholesterol synthesis by14C‐acetate incorporation, in response to the following treatments in lipoprotein‐deficient serum (LPDS)‐supplemented minimum essential medium (MEM): LPDS alone, LDL, mevinolin, mevinolin with LDL, and 25‐hydroxy‐cholesterol (25‐OH‐CH). Complete fetal bovine serum (FBS)‐supplemented MEM was used as control. All colon tumor lines exhibited similarly high endogenous cholesterol synthesis in both FBS and LPDS relative to the fibroblasts which demonstrated low basal levels in FBS and maximal synthesis in LPDS. LDL treatment did not inhibit cholesterol synthesis in colon tumor cells, but suppressed that in the fibroblast by 70%. Sterol repression of cholesterol synthesis mediated by 25‐OH‐CH occurred in all cells. Mevinolin caused a reduction in cholesterol synthesis in the colonic cancer cell lines, which was not further decreased by concurrent addition of LDL. In contrast, in mevinolin‐treated fibroblasts, LDL further inhibited cholesterol synthesis. When the effect of cell density on cholesterol synthesis regulation was evaluated under conditions of sparse density in SW480 and SW1417, results indicated that (i) basal rates of cholesterol synthesis were higher, (ii) LDL inhibited cholesterol synthesis more effectively, and (iii) mevinolin or 25‐OH‐CH had a more pronounced effect than in subconfluent cells. Evaluation of LDL receptor activity through125I‐LDL binding and internalization studies demonstrated LDL receptor expression was reduced by 37% in normal density cells relative to the low density cultures. In contrast to cholesterol synthesis, exogenous LDL could inhibit LDL receptor activity at both densities. Thus subconfluent growing colonic adenoCA cell lines retain the capacity for sterol repression, but, in contrast to normal fibroblasts, exhibit a high endogenous cholesterol synthesis which LDL cannot regulate.
Functional and ultrastructural effects of essential fatty acid deficiency in kidney epithelial cells
Authors: Stoll Lynn L. , Spector Arthur A.
Published: November 2006

Madin‐Darby canine kidney (MDCK) epithelial cells were grown in culture medium supplemented with 1% fetal bovine serum (FBS) to provide a cell culture model of essential fatty acid deficiency (EFAD). 5,8,11‐Eicosatrienoic acid (20∶3n−9) accumulated in cellular phospholipids, and arachidonic acid (20∶4) decreased. A large increase in cellular cholesterol/phospholipid ratio was observed. Hemicyst formation was greatly reduced from normal levels in the EFAD‐MDCK cells. Scanning and transmission electron microscopy revealed that EFAD‐MDCK were much flatter than their normal counterparts. They had much less dense surface microvilli, mitochondria and other organelles were very sparse, except in the perinuclear area, and much of the peripheral cytoplasm was amorphous. The EFAD was rapidly reversed by the addition of as little as 10 μM linoleic or arachidonic acid to the medium. Cells supplemented with 10% FBS, the usual culture condition, displayed borderline EFAD, with intermediate levels of 20∶3n−9 and 20∶4 and hemicyst formation. These studies suggest that EFAD reduces water and electrolyte transport in renal tubular epithelium.
Effect of marine oils supplementation on coagulation and cellular activation in whole blood
Authors: Østerud Bjarne , Elvevoll Edel , Barstad Harald , Brox Jan , Halvorsen Hanne , Lia Karin , Olsen Jan Ole , Olsen Ragnar L. , Sissener Charlotte , Rekdal Øystein , Vognild Eva
Published: November 2006

A study was performed to explore the effects of supplemental intake of various marine oils known to be part of the Eskimo diet. Healthy men and women (134) were randomly selected to consume 15 mL/d of oil from blubber of seal, cod liver, seal/cod liver, blubber of Minke whale, or no oil for ten weeks. Total cholesterol was unchanged in the oil groups, whereas high density lipoprotein cholesterol increased 7% in the seal/cod liver oil (CLO) group (P<0.05) and 11% in the whale oil group (P<0.005). Triacylglycerol was significantly reduced in the CLO group only. The concentration of prothrombin fragment 1+2 was reduced 25% (P<0.05) after whale oil supplementation. No change in fibrinogen or factor VIIc was detected. Tumor necrosis factor generation in lipopolysaccharide (LPS)‐stimulated blood was 30% reduced after whale oil (P<0.05), but was unaffected by intake of seal or CLO. The LPS‐induced tissue factor activity in monocytes was reduced to a significant degree only in the seal/CLO group (34%) and whale oil group (35%) (P<0.05). The most dramatic change in thromboxane B2 in LPS‐stimulated blood was seen after whale oil intake with 44% reduction (P<0.01). Supplementation of a regular diet with a combination of seal oil and CLO and especially with whale oil seems to have beneficial effects on several products thought to be associated with cardiovascular and thrombotic diseases.
Molecular architecture and biophysical properties of phospholipids during thermal adaptation in fish: An experimental and model study
Authors: Fodor Elfrieda , Jones Richard H. , Buda Csaba , Kitajka Klara , Dey Indranil , Farkas Tibor
Published: November 2006

Phospholipids from livers of carps (Cyprinus carpio L.) adapted to winter (5°C) and summer (25°C) temperatures were isolated, and the fatty acid composition of total phospholipids, as well as molecular species composition of diacyl phosphatidylcholines and ethanolamines, were determined. Order parameter of 5‐doxyl stearic acid and steady‐state fluorescence anisotropy of different anthroyloxy fatty acids—[2‐, 12(N‐9‐anthroyloxy)stearic acid and 16(N‐9‐anthroyloxy)palmitic acid—embedded in native and synthetic (16∶0/16∶0, 16∶0/22∶6, 18∶0/22∶6, 18∶1/22∶6, 20∶4/20∶4, 22∶6/22∶6 phosphatidylcholines and 16∶0/18∶1, 18∶1/22∶6 phosphatidylethanolamines) phospholipid vesicles was also determined between −30 and 30°C and 5 and 30°C, respectively. There is an accumulation of 1‐monoenoic, 2‐polyenoic diacyl phosphatidylcholine and ethanolamine with a concomitant reduction of 1‐stearoyl,2‐docosahexaenoyl species in the cold‐adapted state. Despite a 30% accumulation of long‐chain polyunsaturated fatty acids in phospholipids in cold, there is only a 5°C downshift in the solid‐gel to liquid‐crystalline phase transition temperature (−8 vs. −13°C). Vesicles from total phospholipids of cold‐adapted fish proved to be more disordered in all segments than from the warmadapted ones when assayed using 2,12‐(N‐9‐anthroyloxy)stearic and 16‐(N‐9‐anthroyloxy)palmitic acid. Vesicles made from purified phosphatidylcholines showed the same pattern, but they were more disordered than the corresponding total phospholipids. This could be modelled using mixed phospholipid vesicles made of synthetic 16∶0/22∶6 phosphatidylcholine (75%) and either 18∶1/22∶6 phosphatidylethanolamine (25%) vs. 16∶0/18∶1 phosphatidylethanolamine (25%) and comparison of the anisotropy parameters of 100% 16∶0/22∶6 and 100% 18∶1/22∶6 phosphatidylcholine vesicles. Mixing either 16∶0/18∶1 (25%) or 18∶1/22∶6 (25%) phosphatidylethanolamines to 18∶0/22∶6 (75%) phosphatidylcholine shifted down or up, respectively, the transition temperature of vesicles compared to 100% 18∶0/22∶6 vesicles assayed by electron spin resonance spectroscopy using 5‐doxylstearic acid. It is concluded that it is not the gross amount of long‐chain polyunsaturated fatty acids in phospholipids, but rather their specific combination withcis Δ9 monounsaturated fatty acids in the positionsn‐1, especially in phosphatidylethanolamines, that is important in determining the physical properties of biomembranes in relation to adaptational temperature.
Composition of phospholipids of white muscle of six tuna species
Authors: Medina Isabel , Aubourg Santiago P. , Martín Ricardo Pérez
Published: November 2006

A comparative study of the phospholipids of white muscle of six of the comercially utilized tuna species, including quantitative analyses of phospholipid classes and studies of the acyl composition of the major components. Plasmalogen compounds also were identified and quantified. Choline and ethanolamine glycerophospholipids were the most abundant classes in all the samples, as well as the only molecules containing plasmalogens (16∶0, 18∶0, and 18∶1 alkenyl ether chains). The patterns of fatty acid distribution within each of the phospholipid classes showed general similarities in the species analyzed. However, ratios between certain saturated and polyunsaturated fatty acids in different phospholipid classes showed remarkable diffences. The high content of n−3 polyunsaturated fatty acids in the principal phospholipids, such as the plasmalogens, and taking into account the fatty acids possible importance in human nutrition, indicates that the white muscle of tuna species may be a potentially important dietary item.
Palmolein and groundnut oil have comparable effects on blood lipids and platelet aggregation in healthy Indian subjects
Authors: Ghafoorunissa  , Reddy Vinodini , Sesikaran B.
Published: November 2006

Substitution of palmolein (POL) for groundnut oil (GNO) doubles saturated fatty acids and decreases by half the linoleic acid (18∶2n−6) content of Indian diets. The effects of this substitution on selected parameters of cardiovascular risk and membrane functions were studied in middle‐aged subjects. Both metabolic (short‐term) and “in‐home” (long‐term) studies were conducted, and the subjects were crossed over from GNO to POL or vice versa. During both studies and in both sexes, blood pressure, plasma levels of total cholesterol and triglycerides and their distributions in various lipoprotein fractions were not altered. The lower 18∶2n−6 and higher 16∶0 intakes were reflected in fatty acid compositions of cholesteryl esters and triglycerides. However, the plasma and platelet phospholipid fatty acid patterns did not shift toward saturation. The observation that the levels of long‐chain polyunsaturated fatty acids in phospholipids were similar at the end of GNO and POL regimens indicates that 18∶2n−6 furnished during POL regimen may be sufficient to maintain the levels of arachidonic acid in cell membranes. Platelet aggregation, erythrocyte membrane fluidity, and activity of Na+,K+ ATPase, a membrane‐bound enzyme, were essentially similar at the end of the two oil regimens. These results indicate that POL is comparable to GNO and may not induce hypercholesterolemia in Indian subjects consuming cereal‐based diets containing 30% total fat calories and low cholesterol.