bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipids from the paracloacal glands of the American alligator (Alligator mississippiensis)
Authors: Weldon P. J. , Shafagati A. , Wheeler J. W.
Published: November 2006

Lipids from the paracloacal glands of adult and of immature American alligators (Alligator mississippiensis) were analyzed by gas chromatography‐mass spectrometry. Acetate esters (C12−C18) were indicated in the adults' secretions. Immature alligators contain C10−C18 acetates, C12−C18 dodecanoates, tetradecanoates and other high molecular weight esters, and C10−C16 3‐methyl‐butanoates. Cholesterol, C16 and C18 free fatty acids, and α‐tocopherol (vitamin E) were detected in some samples. The results are compared with those published for South American caiman species.
Lipid metabolic interrelationships and phospholipase activity in gustatory epithelium ofictalurus punctatus in vitro
Authors: Rabinowitz Joseph L. , Huque Taufiqul , Brand Joseph G. , Bayley Douglas L.
Published: November 2006

The catfish,Ictalurus punctatus, is an important model for studying the biochemical mechanisms of taste at the peripheral level. The type, amount and metabolic activity of the lipids within this tissue play important roles in taste transduction by forming the matrix in which the receptors for taste stimuli are imbedded and by acting as precursors to second messengers. The metabolic interconversions that occur among the lipids on the taste organ (barbels) of this animal are reported here. When sodium [32P]phosphate was incubated with minced pieces of epithelium from the taste organ ofI. punctatus, phospholipids became labeled. Maximal incorporation occurred near 20 min for lysophosphatidylcholines (LPC),phosphatidylcholines (PC) and phosphatidylinositols (PI). The phosphatidylethanolamines (PE) and phosphatidylserines (PS) became labeled more slowly. The label in LPC and PC declined from 20 min to 120 min, while that of the other fractions increased or was stable over the 20–120 min time period. Upon addition of 1,2‐di‐[1′‐14C]palmitoyl‐sn‐glycero‐3‐phosphocholine to the medium,14C was found within minutes in all of the phospholipids assayed. The amount of label incorporated increased with time, with maximum labeling for all phospholipids occurring at 15 min. However,14C appeared predominantly first (by 5 min) in a neutral lipid fraction (fraction AG, consisting of free fatty acids, mono‐ and diglycerides, triglycerides and methyl esters), then declined rapidly as the phospholipids gradually incorporated more label. Within minutes of addition of 1‐[1′‐14C]palmitoyl‐sn‐glycero‐3‐phosphocholine (lysophosphatidylcholine) the14C‐label was detected in the neutral lipid fraction AG, then in the PC fraction, and later in the other phospholipids. The PC fraction was maximally labeled by 40 min.

Using the appropriate radiolabeled substrates, lysophosphatidylcholine phospholipase A1 and phosphatidylcholine phospholipase D activities were detected in this tissue. Very low activity of a phosphatidylcholine phospholipase A2 was observed. The experiments indicate that there are active and rapid exchange, degradation, synthesis and scavenger pathways of phospholipids in the taste organ of this animal, and suggest that phospholipases A1 and D‐type activities are primarily responsible for the rapid breakdown of LPC and PC.
Effect of dietary palm oil and its fractions on rat plasma and high density lipoprotein lipids
Authors: Sundram Kalyana , Khor Hun Teik , Ong Augustine S. H.
Published: November 2006

Male Sprague Dawley rats were fed semipurified diets containing 20% fat for 15 weeks. The dietary fats were corn oil, soybean oil, palm oil, palm olein and palm stearin. No differences in the body and organ weights of rats fed the various diets were evident. Plasma cholesterol levels of rats fed soybean oil were significantly lower than those of rats fed corn oil, palm oil, palm olein or palm stearin. Significant differences between the plasma cholesterol content of rats fed corn oil and rats fed the three palm oils were not evident. HDL cholesterol was raised in rats fed the three palm oil diets compared to the rats fed either corn oil or soybean oil. The cholesterol‐phospholipid molar ratio of rat platelets was not influenced by the dietary fat type. The formation of 6‐keto‐PGF1α was significantly enhanced in palm oil‐fed rats compared to all other dietary treatments. Fatty acid compositional changes in the plasma cholesterol esters and plasma triglycerides were diet regulated with significant differences between rats fed the polyunsaturated corn and soybean oil compared to the three palm oils.
Separation and differential activation of rat liver cytosolic cholesteryl ester hydrolase, triglyceride lipase and retinyl palmitate hydrolase by cholestyramine and protein kinases
Authors: Ghosh Shobha , Kounnas Maria Z. , Grogan W. McLean
Published: November 2006

Cholesteryl ester hydrolase (CEH), triacylglycerol lipase (TGL) and retinyl palmitate hydrolase (RPH) were measured in 104,000 ×g supernatants from rat liver under optimal conditions for measurement of cytosolic CEH. Similar levels of hydrolytic activity were seen with oil droplet dispersions of cholesteryl oleate, trioleoylglycerol and retinyl palmitate. No cytosolic TGL activity was seen with substrate presented in the triton‐albumin emulsion used for measurement of lipoprotein lipase‐like TGL associated with hepatic plasma membrane. Cytosolic CEH, TGL and RPH were differentially partially purified by both ammonium sulfate precipitation and anion exchange fast protein liquid chromatography (FPLC). Of the three activities, only CEH was stimulated by cholestyramine feeding and by activators of protein kinases A and C. All three activities were inhibited by alkaline phosphatase treatment, although to different degrees. It is concluded that these activities are catalyzed by at least three differentially regulated enzymes with a high degree of specificity for their respective substrates.
Identification of the new 18‐hexacosenoic acid in the spongeThalysias juniperina
Authors: Carballeira Nestor M. , Shalabi Fathi , Maldonado Maria E.
Published: November 2006

The phospholipid fatty acids from the spongeSpheciospongia cuspidifera were studied revealing the presence of the rare 10‐octadecenoic acid (10−18∶1) and a new 2‐methoxyhexadecenoic acid. The phospholipid fatty acids fromThalysias juniperina were also studied revealing the presence of the hitherto unreported 18‐hexacosenoic acid (18−26∶1). These results tend to indicate that the biosynthetic pathway from 10−18∶1 to 18−26∶1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by31P‐NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.
(3H/14C)Beta‐methylheptadecanoic acid subcellular distribution and lipid incorporation in mouse heart
Authors: Livni Eli , Ito Susumu , Kassis Amin I. , Elmaleh David R.
Published: November 2006

Beta‐methylfatty acids are transported into myocardial cells as other fatty acids would be, but are incapable, for example, of undergoing complete catabolism. Our previous studies have established the structure‐location relationship and the imaging characteristics of these analogs. In the present study in mouse myocardium, microautoradiography and electron microscopy were used to show the distribution of [7,8‐3H] beta‐methylheptadecanoic acid ([3H]BMHA) in mitochondria and lipid droplets. Thin‐layer chromatography demonstrated the presence of [1‐14C] beta‐methylheptadecanoic acid ([14C]BMHA) and its metabolites in various lipid pools. These studies complement our earlier findings which showed that similarities exist in the initial metabolic fate of BMHA and physiological fatty acids.
Effect of phosphatidylcholine on the α‐lactalbumin‐induced fusion of vesicles
Authors: Park Byoung Sun , Kim Jeongha , Kim Uh Hee , Kim Hyoungman
Published: November 2006

Previous studies on α‐lactalbumin induced fusion of phosphatidylserine/phosphatidylethanolamine vesicles are extended to vesicles composed of various combinations of phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine and cardiolipin. It was found that inclusion of phosphatidylcholine in the vesicles results in a depression of fusion. This depression of fusion appears to be caused by a reduction in the amount of irreversibly bound α‐lactalbumin to vesicles containing phosphatidylcholine. It is suggested that in this system fusion is dependent upon the extent by which a particular protein segment penetrates the bilayer.
Hepatic biotransformation and choleretic effect of 7‐ketolithocholic acid in the rat
Authors: Kanai Setsuko , Sato Yuko , Nokubo Munetaka , Kitani Kenichi
Published: November 2006

Hepatic biotransformation and the effect on bile flow of 7‐ketolithocholic acid (7‐oxo‐3α‐hydroxy‐5β‐cholan‐24‐oic acid), in comparison to ursodeoxycholic acid, were examined in rats under conditions of continuous infusion of solutions of sodium salts of these bile acids (1.2μmol/min/100 g body wt) for 2 hr. Both bile salts elevated the bile flow rate as well as the bile bicarbonate concentration to a similar degree. The minor difference observed was a transient (10–20 min) and subtle drop of bile flow during the first hour in rats given 7‐ketolithocholate. In ursodeoxycholate infused rats, the major bile salt in the bile was its taurine conjugate, although excretion of tauroursodeoxycholate dropped considerably during the second hour. In 7‐ketolithocholate infused rats, the major bile salt in the bile was again, its taurine conjugate, but ursodeoxycholate and chenodeoxycholate and their conjugates were also excreted. In contrast to ursodeoxycholate infused rats, the drop in excretion of taurine conjugates and the increase of glycine conjugates in rats infused with 7‐ketolithocholate were more rapid. In rats infused with 7‐ketolithocholate, excretion of ursodeoxycholate and its conjugates was significantly higher than the corresponding values for chenodeoxycholate, suggesting that 7‐ketolithocholate is reduced predominatly to the 7β‐epimer in this species. However, the concentration of ursodeoxycholate and its conjugates excreted into the bile in rats infused with 7‐ketolithocholate was only 10% of that of rats infused with ursodeoxycholate, yet the magnitude of choleresis and the rise in bile bicarbonate concentration were similar in both experiments. Therefore, it is suggested that the bicarbonate‐rich bile, induced by 7‐ketolithocholate infusion, is caused mainly by 7‐ketolithocholate rather than by its metabolite, ursodeoxycholate.
Thiobarbituric acid‐reactive substances from peroxidized lipids
Authors: Kosugi Hiroko , Kojima Takashi , Kikugawa Kiyomi
Published: November 2006

The thiobarbituric acid (TBA) reaction was performed on linoleic acid 13‐monohydroperoxide, autoxidized fatty esters, edible fats and oils, rat liver microsomal lipids, and on human erythrocyte ghost lipids in order to determine which substances from peroxidized lipids are TBA‐reactive. The reaction was carried out in 2% acetic acid containing butylated hydroxytoluene using two different reaction modes: a one‐step mode which involves heating at 100°C, and a two‐step mode which involves first treatment at 5°C and subsequent heating at 100°C. Yields of the red 1∶2 malonaldehyde/TBA adduct, as estimated by absorbance, fluorescence intensity and high‐performance liquid chromatography, were much higher than the malonaldehyde content as determined by direct chemical analysis. Yields of red pigment obtained by the two‐step mode were slightly higher than those obtained by the one‐step mode. Pigment yields were dramatically increased by addition oft‐butyl hydroperoxide. Red pigment formation from alkenals and alkadienals was similarly enhanced by the two‐step mode or by addition oft‐butyl hydroperoxide, whereas pigment formation from malonaldehyde was not. It appears likely that a component of the total red pigment formed from the peroxidized lipids was due to aldehyde species other than malonaldehyde.
Gas chromatographic analysis of free and bound malonaldehyde in rat liver homogenates
Authors: Ichinose T. , Miller M. G. , Shibamoto Takayuki
Published: November 2006

A gas chromatographic method for the measurement of free and bound malonaldehyde (MA) in rat liver homogenate was developed to investigate biological damage caused by lipid peroxidation. Free MA was derivatized by reaction withN‐methylhydrazine (NMH) to form 1‐methylpyrazole (1‐MP), which was subsequently analyzed by capillary gas chromatography (GC). Bound forms of MA were determined by first hydrolyzing samples in acetic acid, then measuring the free MA as 1‐MP. Bound MA in rat liver was released within 15 min by acid hydrolysis. A slight increase in bound MA levels in rat liver was observed 1 hr after CCl4 treatment, with bound MA then returning to control levels. Free MA levels and thiobarbituric acid assay (TBA) values did not show appreciable changes over a 24‐hr period after CCl4 administration. However, the TBA values were approximately ten times the MA values in most samples.
The occurrence of estrone and estriol intrichostrongylus colubriformis (nematoda)
Authors: Lee Hui‐Minn , Parish Edward J. , Bone Leon W.
Published: November 2006

Mammalian sex steroids and cholesterol wre isolated from the lipid extract of the zooparasitic nematodeTrichostrongylus colubriformis. In addition to the previously identified sex steroids progesterone and testosterone, estrone and estriol were detected and isolated from the mixture. The steroids were analyzed by thin‐layer gas‐liquid and high‐performance liquid chromatography, and their structures confirmed by proton nuclear magnetic resonance and mass spectroscopy.
Time dependent changes occurring in rat liver microsomes upon lipid peroxidation
Authors: Ifoh Fumiaki , Minamide Yoshiyuki , Horie Toshiharu , Awazu Shoji
Published: November 2006

Steady‐state fluorescence anisotropy of diphenylhexatriene and n‐(9‐anthroyloxy)stearic acids (n=2,12) in rat liver microsomes showed a marked increase in the early stages of enzymatically or non‐enzymatically induced lipid peroxidation. The changes in fluorescence anisotropy occurred in parallel with the formation of thiobarbituric acid‐reactive substances (TBA‐RS). Parallel to these changes, the fluorescence emitted from peroxidized microsomes increased markedly in the early stages of lipid peroxidation. In contrast to the changes in the fluorescence anisotropy and in the formation of TBA‐RS, the fluorescence showed a continuing increase over the three hr period of lipid peroxidation. Glucose‐6‐phosphatase was inactivated in the early stages of lipid peroxidation, whereas NADH‐cytochrome b5 reductase underwent a slow deactivation over three hr. The apparently slow deactivation of the peripheral protein may be explained by the formation of fluorescent substances.
Overexpression of aRhizopus delemar lipase gene inEscherichia coli
Authors: Joerger Rolf D. , Haas Michael J.
Published: November 2006

A cloned complementary deoxyribonucleic acid encoding the precursor polypeptide of an extracellular lipase from the fungusRhizopus delemar was altered by site‐directed mutagenesis to generate deoxyribonucleic acid fragments that specifically code for the polypeptides of the proenzyme and the mature form of the lipase. Attempts to produce these polypeptides in enzymatically active form inEscherichia coli revealed toxic effects toward the host. Therefore the polypeptides were expressed as inactive and insoluble forms in the cytoplasm ofE. coli BL21 (DE3) cells using plasmid vector pET11‐d. With this tightly regulated high‐level expression system, lipase and prolipase polypeptides were produced to estimated levels of up to 21% and 15%, respectively, of total cellular protein. The insoluble polypeptides were solubilized in 8 M urea. Refolding into active forms was achieved by treatment with the redox system cystine/cysteine and dilution. Refolded mature lipase was purified to homogeneity by affinity and ion exchange chromatography. The enzyme had a specific activity comparable to that of lipase from the fungal culture. The quantities of pure enzyme obtained from a 1‐L culture ofE. coli exceeded those obtained from the fungal culture by a factor of at least 100. Refolded recombinant prolipase was purified essentially to homogeneity and had a specific activity similar to that of the mature enzyme. Its pH optimum was 7.5, rather than the pH 8 determined for recombinant mature lipase and for the enzyme purified from the fungal culture. Recombinant prolipase retained activity after 15 min incubation at 65°C, while mature lipase retained activity only up to 45°C.
CDPcholine:1,2‐diacylglycerol cholinephosphotransferase from rat liver microsomes. I. Solubilization and characterization of the partially purified enzyme and the possible existence of an endogenous inhibitor
Authors: Ishidate Kozo , Matsuo Ritsuko , Nakazawa Yasuo
Published: November 2006

The solubilization and partial purification of cholinephosphotransferase (CDPcholine:1,2‐diacylglycerol cholinephosphotransferase, EC 2.7.8.2) from rat liver microsomes were examined in the presence of ionic (sodium deoxycholate), nonionic (Triton X‐100,n‐octylglycoside), or zwitter ionic (CHAPS) detergents. Among the four detergents tested, only sodium deoxycholate was found to be an efficient solubilizer of cholinephosphotransferase activity from microsomal membranes, whereas the other three detergents caused irreversible inactivation of the enzyme at the solubilization step. Addition of phospholipids at the solubilization step, or after solubilization of the membrane proteins, could not preserve or reconstitute activity to any extent. The sodium deoxycholate‐solubilized activity was partially purified by gel permeation chromatography (Superose 12HR). The partially purified preparation appeared to consist of a large aggregate containing phospholipids; further dissociation of the protein‐phospholipid complex caused complete inactivation of the enzyme. The partially purified cholinephosphotransferase showed a specific activity of 100–130 nmol/min/mg protein, which is the highest activity reported to date from any tissue source; this amounts to a 4‐fold enrichment of cholinephosphotransferase activity from the original KCl‐washed rat liver microsomes. Ethanolaminephosphotransferase (CDPethanolamine:1,2‐diacylglycerol ethanolaminephosphotransferase, EC 2.7.8.1) activity was copurified and 6‐fold enriched with a total recovery of 60%. During the purification of cholinephosphotransferase activity, a putative endogenous inhibitor of cholinephosphotransferase was also solubilized and was isolated from the microsomal membranes. This heat‐labile, nondialyzable inhibitor was shown to act specifically on cholinephosphotransferase and not on ethanolaminephosphotransferase. Further characterization of the inhibitory activity revealed that it may act at the binding step of the cholinephosphotransferase to its lipid substrate, diacylglycerol.
Hypertension in rats does not potentiate hypercholesterolemia and aortic cholesterol deposition induced by a hypercholesterolemic diet
Authors: Mori Hiromi , Ishiguro Kyohko , Okuyama Harumi
Published: November 2006

The effect of a hypercholesterolemic diet (HCD) on hyperlipemia and atherogenesis was investigated using normotensive Wistar/Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and stroke‐prone SHR (SHRSP), with systolic blood pressures increasing in that order. Feeding an HCD diet containing cholesterol, cholate and suet induced hypercholesterolemia in all the strains examined as compared with a normal diet. The plasma cholesterol levels were significantly higher in WKY than in SHR and SHRSP fed the HCD diet. The HCD diet also induced hepatic fat deposition, particularly deposition of cholesteryl esters, a slight increase in aortic cholesterol deposition, and elevation of both monoenoic/saturated fatty acid ratios and linoleate/arachidonate ratios in tissue lipids. The changes induced in the three strains by the HCD diet were not positively correlated with blood pressures. The HCD diet affected hepatic acyl‐CoA:cholesterol acyltransferase and plasma lecithin:cholesterol acyltransferase activities differently in WKY and SHR which, in addition to the induction of Δ9 desaturase, may partly account for the difference in the diet‐induced changes in the fatty acid compositions of plasma cholesteryl esters. The results indicate that hypertensionper se does not stimulate the development of hypercholesterolemia and arterial cholesterol deposition induced by an HCD diet, suggesting that other factors are involved.
The relationship between fatty acid peroxidation and α‐tocopherol consumption in isolated normal and transformed hepatocytes
Authors: Cogrel Pascale , Morel Isabelle , Lescoat Gerard , Chevanne Martine , Brissot Pierre , Cillard Pierre , Cillard Josiane
Published: November 2006

The response of normal and transformed rat hepatocytes to oxidative stress was investigated. Isolated normal rat hepatocytes and differentiated hepatoma cells (the Fao cell line was derived from the Reuber H 35 rat hepatoma) in suspension were incubated with the ADP/Fe3+ chelate for 30 min at 37°C. Membrane lipid oxidation was assessed by measuring (i) free malondialdehyde (MDA) production by a high‐performance liquid chromatography (HPLC) procedure, (ii) membrane fatty acid disappearance as judged by capillary gas chromatography, and (iii) α‐tocopherol oxidation as determined by HPLC and electrochemical detection. The addition of iron led to increased MDA production in normal as well as in transformed cells, and to simultaneous consumption of polyunsaturated fatty acids (PUFA) and α‐tocopherol. In addition, in Fao cells more α‐tocopherol was consumed during lipid peroxidation while less PUFA was oxidized. Lipid peroxidation was lower in tumoral hepatocytes than in normal cells. This could be due to a difference in membrane lipid composition because of a lower PUFA content and a higher α‐tocopherol level in Fao cells. During oxidation, Fao cells produced 1.5 to 2 times less MDA than normal cells, while in the tumoral cells the amount of oxidized PUFA having 3 or more double bonds was 7 to 8 times lower. Therefore, measuring MDA alone as an index of lipid peroxidation did not allow for proper comparison of the membrane lipid oxidizability of transformed cellsvs. the membrane lipid oxidizability of normal cells.
Determination of 4‐hydroxynonenal by high‐performance liquid chromatography with electrochemical detection
Authors: Goldring Christopher , Casini Alessandro F. , Maellaro Emilia , Del Bello Barbara , Comporti Mario
Published: November 2006

4‐Hydroxy‐trans‐2‐nonenal (HNE) is a highly reactive product of lipid peroxidation originating from the breakdown of phospholipid‐bound polyunsaturated fatty acids of cellular membranes. Despite its biological relevance, this aldehyde is only occasionally determined due to the complexity of previously described procedures. Here we present a simple and very sensitive method for the detection of HNE in biological samples. The method is based on the measurement of the 2,4‐dinitrophenylhydrazone (DNPH) of the aldehyde by electrochemical detection after separation by reverse‐phase high‐performance liquid chromatography (HPLC). The greater sensitivity of this procedure as compared to the ultraviolet detection method commonly employed to measure DNPH derivatives of aldehydes after HPLC will allow the detection of HNE below the pmol level. The detection of HNE is highly reproducible even in normal tissues and cells. Increased amounts of HNE were detected in the livers of animals intoxicated with prooxidant agents such as carbon tetrachloride, bromotrichloromethane or bromobenzene. An exponential increase in HNE (and in malondialdehyde) was measured in peroxidizing liver microsomes (in the NADPH/Fe‐dependent system). The method is also suitable for the study of very small samples, since HNE could be detected in approximately 1 million cultured cells (polyoma virus‐transformed baby hamster kidney fibroblasts); the level rose after exposure of the cells to a Fe3+/ADP prooxidant system.
Microplate methods for determination of serum cholesterol, high density lipoprotein cholesterol, triglyceride and apolipoproteins
Authors: Shireman Rachel B. , Durieux Janine
Published: November 2006

Microtiter plate methods were developed for the enzymatic determination of serum total cholesterol (TC), high density lipoprotein cholesterol (HDL‐C) and triglyceride (TG), and for the turbidometric determination of apolipoproteins. The micromethods resulted in accurate, precise values that were in good agreement with the conventional spectrophotometric assays. The coefficient of variation for TC determinations was 4.5% or less and bias was 5% or less. The lipid micromethod assays are sensitive to 10 mg/dL or less, and the apolipoprotein assay to 1 mg/dL. Less than 100 μL of serum suffices for TC, TG and apoprotein assays; HDL‐C requires an additional 100 μL of serum. Advantages of the micromethods include reductions in assay time and in the amount of reagents required.
A lack of correlation among fatty acids associated with different lipid classes in human milk
Authors: Clark Richard M. , Hundrieser Kenneth E.
Published: November 2006

The fatty acids associated with triacylglycerol, cholesteryl ester, phosphatidylethanolamine, phosphatidylcholine and sphingomyelin in human milk were compared. Ten milk samples were selected for lipid class analysis based on their total lipid polyunsaturated/saturated fatty acid ratio (P/S ratio). The P/S ratio of the selected milk samples ranged from 0.3 to 0.8. Linoleic acid was the predominant fatty acid in milk to affect the P/S ratio. The percentage of linoleic acid in milk triacylglycerol was correlated (r=0.84,P<0.05) with the total milk lipid P/S ratio. Linoleic acid esterified to cholesterol was not correlated with total milk lipid P/S ratio but was correlated (r=−0.66,P<0.05) with the quantity of lipid in the milk. Linoleic acid in the phospholipid classes did not correlate with shift in P/S ratio of the total milk lipid or linoleic acid content of other lipid classes.
Docosahexaenoic acid in developing brain and retina of piglets fed high or low α‐linolenate formula with and without fish oil
Authors: Arbuckle L. Dianne , Innis Sheila M.
Published: November 2006

Docosahexaenoic acid (22∶6n−3) can be synthesized in the liver and/or brain from α‐linolenic acid (18∶3n−3) and is required in large amounts in structural membranes of developing brain and retina. The adequacy and efficacy of formulas containing 18∶3n−3 and/or fish oil in providing 22∶6n−3 for deposition was investigated in piglets fed formula from birth to 15 days. The test formulas contained high (HL) or low (LL) 18∶3n−3 (3.9 or 0.7% of the total formula fatty acids, respectively), or low 18∶3n−3 plus fish oil (LL+FO) to provide C20 and C22 n−3 polyunsaturated fatty acids (0.8% of total fatty acids). Fatty acid analyses of synaptic plasma membrane and retina ethanolamine phospholipids (EPL), which are especially enriched in 22∶6n−3, were compared to those of 15‐day‐old piglets fed sow milk (SM). Feeding LL resulted in lower 22∶6n−3 in synaptic plasma membrane. Fatty acid levels in HL and LL+FO piglets were equivalent to SM, with the exception of lower 22∶5n−3 in the synaptic plasma membrane of LL+FO and in the retina of HL and LL+FO‐fed piglets. Levels of 22∶4n−6 were also lower in the retina of the LL+FO group. The results suggest formula 18∶3n−3 is at least 24% as effective as C20 and C22 n−3 fatty acids as a source of membrane 22∶6n−3. This study shows dietary 18∶3n−3, as the only n−3 fatty acid, can support deposition of comparable percentage of 22∶6n−3 to natural milk. Fish oil also supported tissue levels of 22∶6n−3 similar to natural milk; however, lower 22∶4n−6 may indicate possible inhibitory effects on n−6 metabolism.
Does a threshold for the effect of dietary omega‐3 fatty acids on the fatty acid composition of nuclear envelope phospholipids exist?
Authors: Venkatraman J. T. , Toohey T. , Clandinin M. T.
Published: November 2006

Existence of a dietary maximal level or threshold for incorporation of ω3 fatty acids into membrane phospholipids is of interest as it may further define understanding of the dietary requirement for ω3 fatty acids. To test whether feeding increasing levels of dietary ω3 fatty acids continues to increase membrane ω3 fatty acid content, weanling rats were fed a nutritionally adequate semipurified diet which provided increasing amounts of C20 and C22 ω3 fatty acids, such as 20∶5ω3 and 22∶6ω3. Dietary 20∶5ω3 and 22∶6ω3 were provided by substituting a purified shark oil concentrate of high 22∶6ω3 content for safflower oil high in 18∶2ω6. After four weeks of feeding, nuclear envelopes from four animals in each diet group were prepared, lipid was extracted and phospholipids separated. Arachidonic acid content in membrane phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine was significantly reduced by feeding increased dietary levels of ω3 fatty acids. Decline of 20∶4ω6 level in phospholipid tended to stabilize when the dietary content of total ω3 fatty acids reached 4–5% of total fatty acids. Above this level, dietary ω3 fatty acids did not result in a further decrease in membrane content of 20∶4nω6. Increase in membrane phospholipid content of 20∶5ω3 occurred as the dietary intake of ω3 fatty acids increased from 1.1% to 5% of total fatty acids. A dietary ω3 fatty acid level of 2.2–3% was sufficient to result in maximum incorporation of 22∶6ω3 into membrane phosphatidylcholine and phosphatidylethanolamine, but not into phosphatidylinositol or phosphatidylserine.
Esterification of fatty acids by bovine intramuscular and subcutaneous adipose tissues
Authors: Lin Kuen‐Chiun , Cross H. Russell , Smith Stephen B.
Published: November 2006

Exogenous fatty acid esterification in intramuscular and subcutaneous adipose tissues from 72‐hr fasted orad libitum fed Angus cattle was investigated. Intramuscular (interfascicular) and subcutaneous adipose tissue snips were obtained from the longissimus dorsi muscle and were incubated with radioisotopically labeled fatty acids (palmitate, stearate, oleate, linoleate or linolenate) at three different concentrations (0.3 mM, 0.6 mM and 2.0 mM) to assess rates of fatty acid incorporation into glycerolipids. Rates of fatty acid esterificationin vitro increased with fatty acid concentration in both intramuscular and subcutaneous adipose tissues. For all of the fatty acids investigated, triglycerides were the predominant products (60–85%). Subcutaneous adipose tissue had larger adipocytes and more actively (P<0.05) esterified fatty acids, with the exception of palmitate, than intramuscular adipose tissue. The rate of palmitate esterification was not different between tissues, although intramuscular adipose tissue esterified a greater proportion (P<0.10) of palmitate as triglyceride (85%) than did subcutaneous adipose tissue (75%). Relative rates of incorporation of fatty acids into lipids in intramuscular and subcutaneous adipose tissues were: palmitate > linolenate > linoleate > stearate. In general, 72‐hr fasting did not significantly reduce the rates of fatty acid incorporation in bovine adipose tissues. Results of this study revealed that: i) rates of exogenous fatty acid incorporation into adipose tissue lipids were dependent on the medium fatty acid concentration and adipose tissue depot; and ii) the relative esterification rates of the various fatty acidsin vitro did not necessarily reflect the proportion of these fatty acids in bovine adipose tissues.
Separation and spectral data of the six isomeric ozonides from methyl oleate
Authors: Wu Mingdan , Church Daniel F. , Mahier Thomas J. , Barker Steven A. , Pryor William A.
Published: November 2006

The structures of the products obtained on ozonation of methyl oleate have been re‐examined. The assignments for the six isomeric ozonides of methyl oleate have been made by1H and13C nuclear magnetic resonance (NMR), which were consistent with the retention times observed in high‐performance liquid chromatography; the assignments were confirmed by mass and infrared spectroscopy. Two triplets for the ozonide ring protons of thecis andtrans isomers in the normal (MOO1) and the two cross ozonides (MOO1 and MOO3) can be resolved by 400 MHz NMR. For MOO1 and MOO3, where the two ring carbons are equivalent, two peaks for the ring carbons of each cross ozonides are resolved in the13C NMR spectra, one for thecis and one for thetrans isomer. For MOO2, four peaks for the ring carbons are resolved in the13C NMR spectra, two for thecis and two for thetrans isomer.
Lipids of the earthwormLumbricus terrestris
Authors: Albro Phillip W. , Schroeder Joanna L. , Corbett Jean T.
Published: November 2006

The lipid composition of the earthwormLumbricus terrestris has been reexamined under conditions intended to avoid enzymatic and chemical alterations during storage, extraction, and fractionation procedures. The simple lipids included aliphatic hydrocarbons, steryl esters, glycerides, and at least nine different sterols, all though to be derived from the diet. Free fatty acids, previously considered to be major components of worm lipids, comprised only 0.3% of the total lipid weight. Phospholipids included (in order of relative abundance) phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, as well as sphingomyelin. Glycolipids included cerebrosides and sulfatides containing both glucose and galactose, and gangliosides containing glucosamine and sialic acid. The fatty acid compositions of these lipid classes appeared to be a mixture of what are considered typical plant, bacterial, and animal acids. Several fatty acids found in the worms, includingcis‐vaccenic and eicosapentaenoic acids, were essentially absent from the dietary components, and it is concluded that these acids were synthesized in the worms. The earthworm derives much of its lipid adventitiously, but exerts at least some control over its tissue lipid composition.
Changes in fatty acid composition of phospholipids from liver microsomes and nuclei in rats fed a choline‐free diet
Authors: Kapoor Randhir , Ghoshal Amiya K. , Farber Emmanuel
Published: November 2006

Male F‐344 rats were fed a choline‐free (CF) diet, and changes in phospholipid content, phospholipid fatty acids and phospholipase A2 activity in liver nuclei and microsomes were examined during the first 72 hr. Both nuclei and microsomes showed a decrease in phosphatidylcholine (PC) content. Microsomes showed an increase in PC arachidonate while nuclei showed a decrease. Also, microsomes showed increased activity of phospholipase A2 (PLA2) while nuclei did not. These observations are consistent with the hypothesis that the absence of diene conjugates in liver microsomes in the rats on the CF diet may reflect the increased rate of removal of peroxidized fatty acids by phospholipase A2.
Levels of thiobarbituric acid reactive substances and the cytocidal potential of gammalinolenic and docosahexaenoic acids on ZR‐75‐1 and CV‐1 cells
Authors: Bégin M. E. , Ells G.
Published: November 2006

To clarify the mechanism by which gammalinolenic acid (GLA) is more tumoricidal than docosahexaenoic acid (DHA), we have compared the incorporation of the respective exogenously added ethyl esters GLAe and DHAe into the phospholipids of tumorigenic ZR‐75‐1 and nontumorigenic CV‐1 cells relative to the ability of the cells to survive and to accumulate thiobarbituric acid reactive substances (TBARS). GLA and DHA were incorporated in the phospholipids to the same extent, but GLA disappeared more rapidly than DHA in both cell lines. GLAe induced about twice as much intracellular TBARS as DHAe in both cell lines, but killed ZR‐75‐1 cells four times more effectively than DHAe. DHAe induced 11–15 fmoles malondialdehyde‐equivalents (MDA‐eq)/cell in both ZR‐75‐1 and CV‐1 cells, whereas GLAe induced 5–6 times more TBARS in ZR‐75‐1 cells (26–30 fmoles MDA‐eq/cell) than in CV‐1 cells (5–6 fmoles MDA‐eq/cell). The results show that there is no difference in GLA and DHA incorporation into phospholipids, but that their metabolism differs in the two cell types. The data also suggest that the cytocidal potential is related to TBARS levels in a nonlinear fashion. The relationship between excess prostaglandin production and excessive cell death due to GLA is discussed.
Phospholipid composition of cultured human endothelial cells
Authors: Murphy Eric J. , Joseph Laurie , Stephens Ralph , Horrocks Lloyd A.
Published: November 2006

Detailed analyses of the phospholipid compositions of cultured human endothelial cells are reported here. No significant differences were found between the phospholipid compositions of cells from human artery, saphenous and umbilical vein. However, due to the small sample sizes, relatively large standard deviations for some of the phospholipid classes were observed. A representative composition of endothelial cells is: phosphatidylcholine 36.6%, choline plasmalogen 3.7%, phosphatidylethanolamine 10.2%, ethanolamine plasmalogen 7.6%, sphingomyelin 10.8%, phosphatidylserine 7.1%, lysophosphatidylcholine 7.5%, phosphatidylinositol 3.1%, lysophosphatidylethanolamine 3.6%, phosphatidylinositol 4,5‐bisphosphate 1.8%, phosphatidic acid 1.9%, phosphatidylinositol 4‐phosphate 1.5%, and cardiolipin 1.9%. The cells possess high choline plasmalogen and lysophosphatidylethanolamine contents. The other phospholipids are within the normal biological ranges expected. Phospholipids were separated by high‐performance liquid chromatography and quantified by lipid phosphorus assay.
Unusual tetraene sterols in some phytoplankton
Authors: Patterson G. W. , Gladu P. K. , Wikfors G. H. , Lusby W. R.
Published: November 2006

Sterols were analyzed from four phytoplankton strains which are under investigation as possible sources of food for oysters in culture. One strain ofPyramimonas contained only 24‐methylenecholesterol as a major sterol component.Pyramimonas grossii, Chlorella autotrophica andDunaliella tertiolecta each contained a complex mixture of C28 and C29 sterols with Δ7, Δ5,7 and Δ5,7,9(11) nuclear double bond systems. Sterols were found both with and without the C‐22 side chain double bond. Ergosterol and 7‐dehydroporiferasterol were the principal sterols in each of the latter three species, which also contained the rare tetraene sterols, 24‐methylcholesta‐5,7,9(11),22‐tetraen‐3β‐ol and 24‐ethylcholesta‐5,7,9(11),22‐tetraen‐3β‐ol.
Comparison of the effect of the amount and degree of unsaturation of dietary fat on plasma low density lipoproteins in vervet monkeys
Authors: Kruger M. , Smuts C. M. , Benadé A. J. S. , Fincham J. E. , Lombard C. J. , Albertse E. A. , van der Merwe K. J.
Published: November 2006

The effects of the degree of unsaturation and of the amount of dietary fat on low density lipoprotein (LDL) concentration and composition were determined in vervet monkeys. Diets with fat contents of 41, 31 and 18% energy, each with a low and a high polyunsaturated to saturated fatty acid ratio (P/S; 0.27–0.38 and 1.13–1.47) were fed to six female vervet monkeys for two months. Another six females were given a low fat, high P/S diet for the same period of time, to serve as a reference. The cholesterol contents of the diets were low (21–33 mg per day) and relatively constant. LDL cholesterol concentrations decreased significantly (P≤0.01) when the dietary fat content decreased from 31 to 18% of energy. The dietary P/S ratio only affected LDL cholesterol concentrations during moderate (31% of energy) fat intake, where LDL cholesterol increased (P≤0.01) with a decrease in dietary P/S. Substantial individual variations were observed in LDL cholesterol concentration responses to dietary fat changes. The changes in LDL cholesterol concentrations were the result of changes in the concentration of LDL particles, as the molecular composition did not differ significantly between dietary periods. The high density lipoprotein choelsterol and the plasma triacylglycerol concentrations were not influenced by the dietary fat changes. During the high P/S diets, the percentage of 18∶2 (linoleic acid) increased (P≤0.01) and that of 18∶1 (oleic acid) decreased (P≤0.01) in LDL esterified cholesterol, as compared to the low P/S diets. In adipose tissue triacylglycerol the percentage of 18∶2 was three times higher (P≤0.01) during the high P/S diets than during the low P/S diets. A decrease in the amount of dietary fat (from 31 to 18% of energy) was associated with an increase in the percentage of 18∶1 in LDL esterified cholesterol.
Effects of dietary linseed oil and marine oil on lipid peroxidation in monkey liverin vivo andin vitro
Authors: Kaasgaard Svend G. , Hølmer Gunhild , Høy Carl‐Erik , Behrens Willy A. , Beare‐Rogers Joyce L.
Published: November 2006

Diets rich in linoleic acid (CO) from corn oil, or in linoleic acid and either α‐linolenic acid (LO) based on linseed oil or n−3 fatty acids (MO) from menhaden oil were fed to male and female Cynomolgus monkeys for 15 wk. In the liver a 40% reduction of α‐tocopherol occurred in the MO group relative to the CO and LO groups followed by increased formation of lipofuscinin vivo. A four‐fold increase of α‐tocopherol in the MO diet (MO+E) brought the level in the liver to that found with CO and LO. The increased peroxidation in the MO group in the liver phospholipids was associated with the replacement of 60% of the n−6 fatty acids by n−3 fatty acids from menhaden oil. Similar fatty acid profiles were found in groups fed MO and MO+E, respectively. Compared to the CO fed group, feeding α‐linolenic acid only resulted in a slight incorporation of n−3 fatty acids in the liver membranes mainly due to a direct incorporation of α‐linolenic acid. However, in monkeys fed menhaden oil more than 30% of the total fatty acids in the liver phospholipids were n−3 fatty acids. The various diets did not influence the activity of liver catalase (EC 1.11.1.6) nor superoxide dismutase (EC 1.15.1.1), but glutathione‐peroxidase activity (EC 1.11.1.9) was higher in monkeys fed the MO diet. The catalase activity in females was 20% higher than in males. In anin vitro assay, liver microsomes from monkeys fed the MO diet or the MO diet supplemented with tocopherol produced similar amounts of thiobarbituric acid reactive substances and at a much higher rate than microsomes from the CO and LO groups. It appeared that α‐tocopherol did not protect long‐chain n−3 C20 and C22 fatty acids as well as n−6 fattya acids against peroxidation. The present data showed that monkeys were not fully able to compensate for increased peroxidative stress but a four‐fold supplement of vitamin E to the diets reduced the oxidation.
Modulation of cyclic nucleotide phosphodiesterase by dietary fats in rat heart
Authors: Dubois Madeleine , Croset Martine , Némoz Georges , Lagarde Michel , Prigent Annie‐France
Published: November 2006

Feeding oils of different fatty acid composition modifies the fatty acid composition of cardiac membrane phospholipids, thereby inducing changes in cardiac contractility and altering response of adenylate cyclase to catecholamines. In the present study, the effect of such dietary manipulations on cyclic nucleotide phosphodiesterase, which is involved in the control of cyclic nucleotide intracellular levels and in the control of cardiac contractility, was investigated. Rats were fed either a saturated fatty acid‐enriched diet (8 weight percent [%] coconut oil +2% sunflower oil), an n−6 fatty acid‐enriched diet (10% sunflower oil) or an n−3 fatty acid‐enriched diet (8% fish oil +2% sunflower oil). The fatty acid composition of cardiac phospholipids, as well as the nonesterified fatty acid content of heart were markedly altered by the diets. The 18∶2n−6 and 20∶4n−6 content of cardiac phospholipids was markedly (−49%) depressed by fish oil as compared with sunflower oil feeding, but the nonesterified fatty acid level of heart membrane was lowest in coconut oil‐fed rats. In addition, fish oil feeding more drastically depressed the n−6/n−3 fatty acid ratio in the nonesterified fatty acid pool than in cardiac phospholipids. Cyclic AMP phosphodiesterase activity was the lowest in both the particulate and soluble fractions of heart from rats fed sunflower oil, whereas cyclic GMP phosphodiesterase activity was not altered by the diets. Cyclic AMP phosphodiesterase activity was decreased by 18 and 12% in heart membranes of the sunflower oil group as compared to that of the coconut oil and fish oil groups, respectively. In heart cytosol, the activity decreased by 30% when compared with the activity of the coconut oil group. Additionalin vitro experiments showed that polyunsaturated fatty acids were more potent inhibitors of cyclic AMP phosphodiesterase than saturated fatty acids. These results suggest that polyunsaturated fatty acid‐enriched diets might decrease heart cyclic AMP phosphodiesterase activity by increasing non‐esterified polyunsaturated fatty acids, especially those of the n−6 series, but more complex and indirect mechanisms are very likely to be involved.
trans fatty acids, 5. Fatty acid composition of lipids of the brain and other organs in suckling piglets
Authors: Pettersen Jan , Opstvedt Johannes
Published: November 2006

The effects of dietarytrans fatty acids on the fatty acid composition of the brain in comparison with other organs were studied in 3‐wk‐old suckling piglets. In Experiment (Expt.) 1 the piglets were delivered from sows fed partially hydrogenated fish oil (PHFO) (28%trans), partially hydrogenated soybean oil (PHSBO) (36%trans) or lard (0%trans). In Expt. 2 the piglets were delivered from sows fed PHFO, hydrogenated fish oil (HFO) (19%trans) or coconut fat (CF) (0%trans) with two levels of dietary linoleic acid (1 and 2.7%) according to factorial design. In both experiments the mother's milk was the piglets' only food. The level of incorporation oftrans fatty acids in the organs was dependent on the levels in the diets and independent of fat source (i.e., PHSBO, PHFO or HFO). Incorporation oftrans fatty acids into brain PE (phosphatidylethanolamine) was non‐detectable in Expt. 1. In Expt. 2, small amounts (less than 0.5%) of 18∶1trans isomers were found in the brain, the level being slightly more on the lower level of dietary linoleic acid compared to the higher. In the other organs the percentage of 18∶1trans increased in the following order: heart PE, liver mitochondria PE, plasma lipids and subcutaneous adipose tissue. Small amounts of 20∶1trans were found in adipose tissue and plasma lipids. Other very long‐chain fatty acids from PHFO or HFO (i.e., 20∶1cis and 22∶1cis+trans) were found in all organ lipids except for brain PE. Dietarytrans fatty acids increased the percentage of 22∶5n−6 in brain PE. Except for the brain and the heart, dietarytrans fatty acids reduced the percentage of saturated fatty acids and increased the percentage of monoenoic acids (includingtrans). The overall conclusion was that dietarytrans fatty acids had no noticeable effect on the brain PE composition but slight to moderate effects on the fatty acid profile of other organs of suckling piglets.