bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipids and fatty acids of the horseshoe crabsTachypleus gigas andCarcinoscorpius rotundicauda
Authors: Pakrashi Satyesh C. , Duffa Pradeep K. , Achari Basudeb , Misra Suniti , Choudhury Amalesh , Chattopadhyay Subhashis , Ghosh Amitabha
Published: November 2006

Total lipids from hepatopancreas of the horseshoe crabs,Tachypleus gigas andCarcinoscorpius rotundicauda, obtained in 7.6 and 3.3% wet weight respective yields, were fractionated by various chromatographic techniques and identified by gas‐liquid chromatography and spectroscopic methods. Fatty acid‐containing lipids were rich in 16∶0 (8.0–25%), 18∶1ω9 (6.9–22%) and 18∶2ω6 (6.8–18.5%); appreciable amounts of 16∶1ω7, 18∶3ω3, 20∶5ω3 and 22∶6ω3 were also present. The level of 26∶0 in the hydrocarbon fractions was unusually high (64 and 68%). Carbon chain lengths of major wax esters were 44, 46 and 48 forT. gigas and 38, 40 and 42 forC. rotundicauda. 1‐O‐Alkyl diglycerides were 7.2 and 9.1% of the total lipids in the two species and contained 14∶0(20%), 16∶0(60%) and 18∶0(20%) alkyl chains along with a relatively higher percentage (32–35%) of saturated fatty acids. High levels of cholesterol (>50% of total sterol) in the free and combined state were encountered in both samples, phospholipid contents being 40 and 35%, respectively, and contained highest levels of unsaturated fatty acids.
Black currant seed oil feeding and fatty acids in liver lipid classes of guinea pigs
Authors: Crozier G. L. , Fleith M. , Traitler H. , Finot P. A.
Published: November 2006

Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma‐linolenic (18∶3 n−6) and stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine were determined.

Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids, proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant seed oil group compared with the walnut oil group.

Feeding black currant seed oil resulted in significant increases of dihomogamma‐linolenic acid (20∶3 n−6) in all liver lipid classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo‐gamma‐linolenic acid/arachidonic acid was significantly (2.5‐fold in PI to 17‐fold in cholesteryl esters) higher in all lipid classes from the black currant seed oil fed group.
Three new and bioactive icosanoids from the temperate red marine algaFarlowia mollis
Authors: Solem Michele L. , Jiang Zhi D. , Gerwick William H.
Published: November 2006

Three new dihydroxyicosanoids, 12(R),13(R)‐dihydroxyicosa‐5(Z), 8(Z),10(E),14(Z)‐tetraenoic acid, 12(R),13(R)‐dihydroxyicosa‐5(Z), 8(Z),10(E),10(Z),17(Z)‐pentaenoic acid and 10(R*),11(R*)‐dihydroxyoctadeca‐6(Z),8(E),12(Z)‐trienoic acid, have been isolated from a previously unstudied temperate red marine alga,Farlowia mollis (Cryptonemiales, Rhodophyta). The structures of these new metabolites have been deduced from detailed nuclear magnetic resonance and mass spectrometry analyses on stabilized diacetate‐methyl esters and stereochemistry deduced by1H NMR couplings and CD analysis of a dibenzoate derivative. Collectively, these new natural products modulate fMLP‐induced superoxide anion generation in human neutrophils, inhibit the conversion of arachidonic acid to lipoxygenase products by human neutrophils, and inhibit the functioning of the dog kidney Na+/K+ ATPase.
Fish oil prevents change in arachidonic acid and cholesterol content in rat caused by dietary cholesterol
Authors: Garg M. L. , Wierzbicki A. , Keelan M. , Thomson A. B. R. , Clandinin M. T.
Published: November 2006

Rats were fed diets high in either saturated fat (beef tallow) or α‐linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil. Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6‐, 5.5‐, 2.6‐fold, respectively). Feeding fish oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high dietary load of cholesterol.
Developmental regulation of sterol biosynthesis inCucurbita maxima L.
Authors: Fenner Gregeory P. , Patterson Glenn W. , Lusby William R.
Published: November 2006

Twenty‐two sterols were identified by capillary gas chromatography and capillary gas chromatography/mass spectroscopy inCucurbita maxima grown under green‐house conditions. Both whole plants and individual tissues (leaves, stems, roots, cotyledons, flowers) were analyzed at weekly intervals during the 12‐week development of the plant. In whole plants, sterol accumulation parallels plant growth except for a period in the mid‐life cycle where there is a reduction in the amount of sterol accumulated on a total sterol/plant and mg sterol/g dry wt basis. This reduction in the amount of sterol is coincident with the visual onset of flowering. During development, the percent contribution of each class of sterol (Δ5_, Δ7_, Δ0_‐sterols) remains relatively constant. However, the percent contribution of an individual sterol species varies depending on the tissue examined and the developmental period selected for analysis. While the young plant (<2 weeks) possesses elevated levels of sterols with the Δ25(27)‐double bond, the trend was toward a reduction in the amounts of these sterols with development. Leaves and stems accumulate large quantities of 24ζ‐ethyl‐5α‐cholesta‐7,22‐dien‐3β‐ol (7,22‐stigmastadienol) and 24ζ‐ethyl‐5α‐cholest‐7‐en‐3β‐ol (7‐stigmastenol), while roots accumulate only 7,22‐stigmastadienol as their principal sterol. Male flowers and roots were found to contain elevated levels of Δ5_‐sterols.
Effects of dietary n−3 polyunsaturated fatty acids on phospholipid composition and calcium transport in mouse cardiac sarcoplasmic reticulum
Authors: Croset M. , Black J. M. , Swanson J. E. , Kinsella J. E.
Published: November 2006

The effects of dietary n−3 and n−6 polyunsaturated fatty acids on the fatty acid composition of phospholipid, Ca++· Mg++ ATPase and Ca++ transport activities of mouse sarcoplasmic reticulum were investigated. Mice were fed a 2 weight percent fat diet containing either 0.5 weight percent ethyl esters of 18∶3n−3, 20∶5n−3 or 22∶6n−3 as a source of n−3 polyusaturated fatty acid or 0.5 weight percent safflower oil as a cource of n−6 polyunsaturated fatty acid for 10 days. Olive oil (2 weight percent) was used as a control diet. Although feeding n−6 polyunsaturated fatty acid induced very little modifications of the phospholipid sarcoplasmic reticulum fatty acid composition, feeding n−3 polyunsaturated fatty acid altered it markedly. Inclusion of 18∶−3, 20∶5n−3 or 22∶6n−3 in the diet caused an accumulation of 22∶6n−3, which replaced 20∶4n−6 and 18∶2n−6 in phospholipid sarcoplasmic reticulum. The saturated fatty acids were significantly increased with a concurrent reduction of 18∶1n−9. These changes in the fatty acid composition resulted in a decrease in the values of the n−6/n−3 polyunsaturated fatty acid ratio and a decrease in the ratio of 20 carbon to 22 carbon fatty acids esterified in the phospholipid sarcoplasmic reticulum. This was associated with a decrease in Ca++ uptake by n−3 polyunsaturated fatty acid enriched sarcoplasmic reticulum vesicles as compared with n−6 fatty acid and control diet sarcoplasmic reticulum vesicles. However, neither the affinity for Ca++ nor the maximal velocity of ATP hydrolysis activity of Ca++·MG++ ATPase were altered by the different diets. The data suggest that the incorporation of 22∶6n−3 and/or the decrease of 20∶4n−6 plus 18∶2n−6 in the phospholipid sarcoplasmic reticulum may affect the membrane lipid bilayer structure and make it more permeable to Ca++.
Skeletal lipid depletion in spawning salmon
Authors: Phleger C. F. , Laub R. J. , Benson A. A.
Published: November 2006

Skeletal tissues in Pacific salmon are composed of significant amounts of lipid (which serves as an energy supply), that is then depleted during migration and freshwater spawning. The vertebral centra and neurocrania of ocean prespawning pink salmonOncorhynchus gorbuscha, although composed respectively of 2.9–13% and 0.5–6.3% lipid (each by dry weight), amount only to 0–1.6% and 0–1.4% in river postspawning individuals. The skeletal lipids are 91–98% triacylglycerol with only small amounts of phospholipid and cholesterol. Triacylglycerols of carbon numbers 47, 49 and 51 are selectively depleted during spawning, whereas there are increases in the relative amounts of those of carbon numbers 55, 57, 59 and 61. The patterns of variation of the skeletal lipids of coho salmon,O. kisutch, chum salmon,O. keta, and sockeye salmon,O. nerka are similar to those ofO. gorbuscha.
Effects of dietary fish oil on human mammary carcinoma and on lipid‐metabolizing enzymes
Authors: Borgeson Charlotte E. , Pardini Lani , Pardini Ronald S. , Reitz Ronald C.
Published: November 2006

The growth rate of a human mammary carcinoma, MX‐1, was significantly reduced in athymic “nude” mice fed fish oil. Tumors from the fish oil‐fed animals also showed a greater sensitivity to two anti‐neoplastic agents, mitomycin C and doxorubicin. Mitochondria were isolated from control livers, host livers and tumors from fish oil‐and corn oil‐fed animals, and increased levels of 20∶5n−3 and 22∶6n−3 were found in mitochondrial lipids in all three tissues from the fish oil‐fed animals. To investigate the effect of dietary n−3 fatty acids on lipid metabolism, the activity of the acyl‐CoA:carnitine acyltransferase and three acyl‐CoA desaturases were measured. Carnitine acyltransferase activity toward all four acyl‐CoA substrates tested was markedly increased in mitochondria from liver by feeding fish oil. In mitochondria from tumors, feeding fish oil resulted in an increased activity toward only 18∶3n−3. These data suggest that fish oil may induce an increase in the oxidation of fatty acids. The Δ9‐desaturase activity was decreased in microsomes from liver and tumor from fish oil‐fed animals. However, both the Δ6 and Δ5 desaturases were increased in tumor and in control liver as a result of feeding fish oil. The Δ5 desaturase was not altered in microsomes from the host animals. The effect of fish oil on the Δ5 and Δ6 desaturases may involve alterations to metabolism of specific polyunsaturated fatty acids especially in the tumor tissue.
The common occurrence of furan fatty acids in plants
Authors: Hannemann Kerstin , Puchta Volker , Simon Ernst , Ziegler Herta , Ziegler Gunter , Spiteller Gerhard
Published: November 2006

The observation that F‐acids (1) occur in rat chow initiated a search for F‐acids in human diet. We observed that the amount of F‐acids with a pentyl side chain in α‐position taken up with a one‐day diet correlates well with the amount of excreted degradation products, the pentyl urofuran acids (2), (3) and (4). Therefore it can be concluded that F‐acids with a pentyl side chain are not produced in the human body but are introduced through the diet. The origin of F‐acids carrying an α‐propyl side chain is less clear. The amount of propyl‐urofuran acids (2) and (3) excreted in urine was found in one case out of three to be five times higher than the amount of F‐acids carrying a propyl group in α‐position taken up by the diet. Therefore, it can presently not be excluded that a portion of the propyl F‐acids is produced by the body.

F‐acids found in human food are mainly introduced into the body by vegetables and fruits. F‐acids were found also in birch leaves in considerable amounts, as well as in grasses, dandelion and clover leaves. Thus, we can conclude that F‐acids are common constituents of plants.
Modulation of eicosanoid production and cell‐mediated cytotoxicity by dietary α‐linolenic acid in BALB/c mice
Authors: Fritsche Kevin L. , Johnston Patricia V.
Published: November 2006

The effects of dietary α‐linolenic acid (18∶3n−3) on fatty acid composition, eicosanoid production, and cell‐mediated cytotoxic activity of immune cells before and after challenge with virus or poly I‐C from BALB/c mice were studied. Weanling BALB/c mice were fed purified diets containing either 10%‐by‐weight corn oil or linseed oil providing a ratio of 18∶3n−3 to 18∶2n−6 of 1/32 or 2/1, respectively, for 6–10 weeks. Fatty acid analysis of splenocyte phospholipids showed an appreciable increase in the percentage of n−3, and a decrease in n−6, fatty acids in splenocytes from mice fed the linseed oil diet. Splenocyte prostaglandin E and peritoneal exudate cell leukotriene C production was significantly lower in the linseed oilfed mice. In general, cell‐mediated cytotoxic activity was similar for immune cells from linseed oil and corn oil‐fed mice. However, 6 days after the viral challenge, splenocyte cell‐mediated cytotoxic activity was significantly higher in linseed oil mice. This higher activity was associated with nonspecific cytotoxicity rather than that of viral‐specific cytotoxic T‐lymphocytes. Cell yields from the spleen and peritoneum were frequently significantly higher in linseed oil mice. Interactions between dietary 18∶3n−3, eicosanoid production, and immune cell proliferation and/or migration are discussed. In summary, feeding mice a diet rich in 18∶3n−3 elevates immune cell n−3 fatty acid content, reduces eicosanoid synthesis and, to a limited extent, enhances the cell‐mediated cytotoxic response to a viral challenge.
Synergistic enhancement of the antiproliferative activity ofcis‐diamminedichloroplatinum(II) by the ether lipid analogue BM41440, an inhibitor of protein kinase C
Authors: Hofmann Johann , Ueberall Florian , Posch Lydia , Maly Karl , Herrmann Dieter B. J. , Grunicke Hans
Published: November 2006

The new phospholipid analogue 3‐hexadecylmercapto‐2‐methoxy‐methyl‐propyl‐1‐phosphocholine inhibits the phospholipid‐calcium‐dependent protein kinase, partially purified from Walker carcinoma cells with a Ki value of 0.56 μM. The compound inhibits the phorbol ester stimulated phosphorylation of the ribosomal protein S6 indicating that the depression of Ca2+‐phospholipid‐dependent protein kinase by the alkyl phospholipid also occurs in intact cells. The dose effect curve for the inhibition of cell proliferation by 3‐hexadecylmercapto‐2‐methoxy‐methyl‐propyl‐1‐phosphocholine in Walker cells exhibits a close correlation to the dose effect curve for the depression of Ca2+‐phospholipid‐dependent protein kinase activity. Although alternative mechanisms cannot be excluded, the data suggest that the growth inhibitory activity of 3‐hexadecylmercapto‐2‐methoxy‐methyl‐propyl‐1‐phosphocholine correlates with the inhibition of Ca2+‐phospholipid‐dependent protein kinase. The antiproliferative activity of 3‐hexadecylmercapto‐2‐methoxymethyl‐propyl‐1‐phosphocholine is synergistically enhanced bycis‐diamminedichloroplatinum(II).
Quantification, characterization and fatty acid composition of lysophosphatidic acid in different rat tissues
Authors: Das Arun K. , Hajra Amiya K.
Published: November 2006

The amount and composition of lysophosphatidate present in different rat tissues have been estimated by an internal standard method in which a synthetic unnatural isomer (1‐heptadecanoyl‐rac‐glycerol‐3‐phosphate) was added to the total lipid extracts, and the fatty acid composition of purified lysophosphatidate was determined. Lipids from tissues were extracted under acidic conditions, and the lysophosphatidate was purified by solvent partitions followed by thin‐layer chromatography in multiple solvent systems. The purified lipid was shown to be 1‐acyl‐sn‐glycerol‐3‐phosphate by chromatographic and chemical analysis, by its resistance to hydrolysis when treated with phospholipase A2 and also by its complete conversion to 1‐acyl‐sn‐glycerol when treated with alkaline phosphatase. The fatty acid consituents of this lipid were determined by gas‐liquid chromatography of the derived methyl esters. The concentrations (nmol/g of tissue) of lysophosphatidate in various tissues were: 86.2±4.2 in brain, 60.3±6.3 in liver, 46.4±6.5 in kidney, 30.6±5.0 in testis, 22.3 in heart and 19.3 in lung. Mostly (80%) saturated fatty acids were found to be present in this lyso lipid. A significantly high level of stearic acid was present in this lipid from all the tissues (50–60% in liver, kidney, brain and testis, and about 40% in heart and lung) compared to plamitic acid (10–15% in liver, kidney and brain and 25–30% in testis, heart and lung). The fatty acid compositions of phosphatidic acid, the putative product of lysophosphatidate acylation, from different tissues were also determined and palmitate was found to be the major saturated fatty acid. These results suggest that tissue lysophosphatidic acid is not only formed byde novo biosynthesis but is also generated via the breakdown of phospholipids such as phosphoinositides.
The essential fatty acid requirement for azoxymethane‐induced intestinal carcinogenesis in rats
Authors: Bull Arthur W. , Bronstein Joel C. , Nigro Norman D.
Published: November 2006

The essential fatty acid requirement for the development of intestinal carcinogenesis was determined and compared to the overall essential fatty acid status of the animals as measured by the triene/tetraene ratio in the plasma, liver and colon. To induce tumors, male Sprague‐Dawley rats were given two weekly injections (20 mg/kg body wt) of azoxymethane. Two weeks after the last injection, the rats were divided into groups of 25 and given one of six diets containing various levels of essential fatty acids (as linoleate). The diets contained 5% total fat and were prepared by mixing safflower oil (high essential fatty acids, beef fat (low essential fatty acids), and medium chain triglyceride oil (no essential fatty acids). One group of rats was fed a 20% beef fat diet. The range of essential fatty acids was from <0.03% to 1.28% (w/w). Twenty‐six weeks after the first azoxymethane injection, the animals were killed and intestinal tumor incidence and multiplicty were determined. Samples of plasma, liver and colon were also taken for measurement of the triene/tetraene ratio by gas chromatography.

Large bowel tumor incidence showed a dependence on the essential fatty acid content of the diet. The results were as follows: (percent essential fatty acids: percent tumor incidence) Group A (1.28∶ 72.4), Group B (0.60∶ 73.3), Group C (0.11∶ 55.2), Group D (0.08∶ 39.3), Group E (<0.03∶ 37.9) and Group F, which was fed 20% beef fat, (0.34∶ 88.5). These data suggest the essential fatty acid requirement for colon tumorigenesis is much lower than values previously reported for tumorigenesis in the breast and pancreas. The plasma and liver triene/tetraene ratios showed clear‐cut essential fatty acid deficiency (ratio >0.4) in Groups D and E, although no clinical symptoms were evident. In all dietary groups, the triene/tetraene ratio in the colon was lower than 0.3. In addition in the colon, the percentage of fatty acids present as 20 carbon polyunsaturated fatty acids was lower than in the plasma and liver. These data suggest the colon possesses low levels of the fatty acid desaturase and elongase needed for conversion of linoleate to 20 carbon fatty acids, and therefore, that the colonic requirement for essential fatty acids may be low. Furthermore, in the absence of other clinical symptoms, the reduced tumorigenesis observed in the groups fed low essential fatty acids suggests the essential fatty acid requirement of tumor tissue may be higher than that of normal colon mucosa.
Impact of lemongrass oil, an essential oil, on serum cholesterol
Authors: Elson C. E. , Underbakke G. L. , Hanson P. , Shrago E. , Wainberg R. H. , Qureshi A. A.
Published: November 2006

To test the hypothesis that non‐sterol mevalonate pathway end products lower serum cholesterol levels, we asked 22 hypercholesterolemic subjects (315±9 mg cholesterol/dl) to take a daily capsule containing 140 mg of lemongrass oil, an essential oil rich in geraniol and citral. The paired difference in serum cholesterol levels of subjects completing the 90‐day study approached significance (P<0.06, 2‐tailed t‐test). The subjects segregated into two groups, one consisting of 14 subjects resistant to the protocol and the other consisting of 8 subjects who responded. Paired differences in cholesterol level at 30, 60 and 90 d for resistant subjects were +2±6, +2±7 and −1±6 mg/dl; paired differences for the responding subjects were −25±10 (p<0.05), −33±8 (p<0.01) and −38±10 (p<0.025), respectively. The paired difference (+8±4) in the cholesterol levels of six responders 90 days after the discontinuation of lemongrass oil was not significant.
Suppression of growth in a leukemic T cell line by n−3 and n−6 polyunsaturated fatty acids
Authors: Chow S. C. , Sisfontes L. , Björkhem I. , Jondal M.
Published: November 2006

Proliferation in a lekemic T cell line (Jurkat) was suppressed in a dose dependent manner by n−6 and n−3 polyunsaturated fatty acids (PUFA) added to the culture medium. At high concentrations, PUFA have a cytotoxic effect on Jurkat cells. The inhibitory effect of the PUFA was not due to production of prostaglandins, and lipid peroxidation was only partly responsible. In addition to production of peroxides and aldehydes, lipid peroxidation also reduced the plasmalogen levels in these cells. The antioxidant α‐tocopherol blocked lipid peroxidation and restored the plasmalogen levels to normal. α‐Tocopherol did not totally restore cell proliferation although the MDA‐like products in these cultures (supplemented with PUFA) were reduced to control level. Cultures supplemented with n−6 PUFA seemed to respond better to α‐tocopherol than n−3 PUFA. This suggests that n−6 PUFA may exert their growth inhibitory effect predominantly via lipid peroxidation while different mechanisms might be operating for the n−3 PUFA.
Effects of cholestyramine and squalene feeding on hepatic and serum plant sterols in the rat
Authors: Strandberg Timo E. , Tilvis Reijo S. , Miettinen Tatu A.
Published: November 2006

Hepatic and serum phytosterol concentrations were compared in the rat under basal conditions and during activated cholesterol and bile acid production due to squalene and cholestyramine feeding. Both treatments consistently decreased hepatic and serum levels of sitosterol and campesterol and, unlike esterified cholesterol, esterified plant sterols were not increased in liver during squalene feeding. Serum levels of phytosterols were decreased quite proportionately to those in the liver. The hepatic levels of sitosterol and campesterol closely correlated with each other, but not with cholesterol levels. The percentage esterification of both phytosterols was lower than that of cholesterol. The results indicate that activation of hepatic sterol production leads to depletion of hepatic plant sterols. It is suggested that poor esterification of plant sterols may contribute to this decrease.
Effect of hyperpnea on enzymes of the CDPcholine path for phosphatidylcholine synthesis in rat lung
Authors: Barr Heather A. , Nicholas Terence E. , Power John H. T.
Published: November 2006

We have examined the activity of three enzymes in pulmonary surfactant phosphatidylcholine synthesis following the hyperpnea induced by having rats either inspire 5% CO2/13%O2/82% N2 for 24 hr or swim in thermoneutral water for 30 min. Both stimuli markedly increase frequency and tidal volume of breathing and promote the release of surfactant. Lungs were perfused to remove blood, lavaged, and then homogenized in 1 mM Hepes, 0.15M KCl at pH 7.0. The homogenate was centrifuged at 9,000 g (av) for 10 min to sediment the mitochondria and lamellar bodies and at 100,000 g (av) for 60 min to obtain the microsomal and cytosol fractions. Incubations were carried out under determined optimal conditions and zero order kinetics. Choline kinase (CK), cholinephosphate cytidylytransferase (CP‐cyT) and choline phosphotransferase (CPT) were assayed by the incorporation of [methyl‐14C] choline chloride into phosphocholine, [methyl‐14C]phosphocholine into CDPcholine, and [14C]CDPcholine into phosphatidylcholine, respectively. The incubation products were separated by thin‐layer chromatography. Whereas both forms of hyperpnea increased the activity of CP‐cyT in the microsomal fraction, they had no effect on the activity of either cytosolic CP‐cyT and CK, or microsomal CPT. A similar increase in tidal volume in an isolated perfused rat lung had no effect. We conclude that,in vivo, hyperpnea increases the activity of CP‐cyT, the rate‐limiting enzyme in phosphatidylcholine synthesis. Whether this is due to an increase in the amount of enzyme, or of a cofactor, is unknown.
Acyl lipid metabolism in the oleaginous yeastRhodotorula gracilis (CBS 3043)
Authors: Rolph Carole E. , Moreton Rod S. , Harwood John L.
Published: November 2006

The effects of culture conditions on acyl lipid metabolism in the oleaginous yeastRhodotorula gracilis (CBS 3043) have been investigated. Growth ofR. gracilis under conditions of nitrogen‐limitation resulted in the accumulation of large quantities of triacylglycerols. Thin layer and gas chromatographic analysis of total lipid extracts revealed that the majority of this storage lipid was produced by stationary‐phase cells. In contrast, no such increase in triacylglycerol biosynthesis could be detected in carbon‐limited cells. Freeze‐fracture electron microscopy evidence supported these findings. Growth medium composition was found to have little effect on the relative abundance of the primary phospholipid classes present inR. gracilis. The acyl compositions of triacylglycerols were similarly unchanged by alterations in the composition of the growth medium. In contrast, the degree of unsaturation exhibited by the phospholipid fractions appeared to be particularly sensitive to this external parameter. Acyl quality of triacylglycerol pools extracted from nitrogen‐limited cells were observed to become increasingly saturated as cultures increased in age.

Growth of nitrogen‐limited cells at a lower growth temperature was observed to have little effect on triacylglycerol accumulation. However, both triacylglycerol and phospholipid fractions extracted from these cultures were found to contain increased proportions of the polyunsaturated fatty acid, α‐linolenate.
Microsomal lipid peroxidation: Effect of vitamin E and its functional interaction with phospholipid hydroperoxide glutathione peroxidase
Authors: Maiorino Matilde , Coassin Mariagrazia , Roveri Antonella , Ursini Fulvio
Published: November 2006

The role of vitamin E in the protection against iron dependent lipid peroxidation was studied in rat liver microsomes and Triton‐dispersed microsomal lipid micelles. In these systems, an antioxidant effect of vitamin E at a physiological ratio to phospholipids could be observed only in the presence of phospholipid hydroperoxide glutathione peroxidase (PHGPX) and glutathione. The rationale of this cooperation is discussed on the basis of the hydroperoxyl radical scavenging capacity of vitamin E and the reduction of membrane hydroperoxides by PHGPX. The scavenging of lipid hydroperoxyl radicals by vitamin E, although inhibiting propagation of the peroxidative chain, produces lipid hydroperoxides from which ferrous iron generates alkoxyl radicals that react with vitamin E almost as fast as with fatty acids. Therefore, only if membrane hydroperoxides are continuously reduced by this specific peroxidase does the scavenging of hydroperoxyl radicals by vitamin E lead to an effective inhibition of lipid peroxidation.
Effect of magnesium deficiency on Δ6 desaturase activity and fatty acid composition of rat liver microsomes
Authors: Mahfouz M. M. , Kummerow F. A.
Published: November 2006

Experimental Mg2+ deficiency was induced in a group of rats by feeding them a Mg2+‐deficient diet for 23 days. They were pair‐fed to compare with a control group of rats fed a Mg2+‐sufficient diet. In the Mg2+‐deficient group the plasma total cholesterol and triglyceride levels were increased while HDL‐cholesterol was decreased. In the Mg2+‐deficient group the plasma level of thiobarbituric acid reacting substances (TBARS) used as a measure for lipid peroxidation was increased. The increase was attributed to the increased cytosolic Ca2+ in Mg2+‐deficiency which can cause: 1) increase of hydro and endoperoxide levels as a consequence of the increase of arachidonic acid release and eicosanoid synthesis in Mg2+‐deficiency, and 2) inhibition of the mitochondrial respiratory activity and activation of Ca2+‐dependent proteases which may activate the conversion of xanthine dehydrogenase to xanthine oxidase which generates active O2 species. In the Mg2+‐deficient group, the fatty acid composition of the liver microsomes indicated a slower rate of conversion of linoleic acid to arachidonic acid which was consistent with the decrease of Δ6 desaturase activity in liver microsomes of Mg2+‐deficient rats as measuredin vitro. The decrease of Δ6 desaturase activity was attributed to the lower concentration of actual enzyme molecules as a result of the decreased rate of protein synthesis in Mg2+‐deficiency. The possible effects of the increased catecholamine release in Mg2+‐deficiency are discussed.
Dietary fish oil augments the function and fluidity of the intestinal brush‐border membrane of the carp
Authors: Behar D. , Cogan U. , Viola S. , Mokady S.
Published: November 2006

Two groups of carps were raised on a commerical nutritionally complete diet: one was the control group, the other was fed the same diet enriched with 7% fish oil. The experiment lasted seven months (July through February), during which time the environmental temperature dropped gradually from 25°C to 13°C. Intestinal microvillus membranes were isolated after four and seven month feeding and examined for fluidity by fluorescence polarization with 1,6‐diphenyl‐1,3,5‐hexatriene. The functionality of the membrane was assessed by the activity of the intrinsic enzyme alkaline phosphatase.

The experimental group exhibited increased membrane fluidity and elevated enzyme activity only when the environmental temperature decreased to 13°C. These changes in the membrane properties seemed to correlate with alterations in the fatty acid profile of the membrane phospholipids. Whereas the control group showed some increase in the n−3 C20∶5, C22∶5, and C22∶6 fatty acids most likely due to cold adaptation, the membranes isolated from the group fed fish oil showed a considerably higher level of these fatty acids reflecting the combined effect of the dietary manipulation and cold adaptation.
Thiol esters of 2‐mercaptoethanol and 3‐mercapto‐1,2‐propanediol
Authors: Sonnet Philip E. , Moore Gordon G.
Published: November 2006

2‐Mercaptoethanol and 3‐mercapto‐1,2‐propanediol are selectively S‐acylated by fatty acids with dicyclohexylcarbodiimide (DCC) catalyzed by 4‐dimethylaminopyridine. Since reaction of such thiols with acid halides produces mixtures of S‐ and O‐acylated materials, the procedure using DCC is more efficient. Such thiol esters are valuable as substrates in the study of lipase activity, using Ellman's Reagent in a continuous spectrophotometric assay. This selective synthesis will facilitate the study of fatty acid residues that are less available. Rearrangement of S‐ to O‐acylated compounds occurs only slowly under the conditions of the lipase assay and should not significantly affect activity measurements. Using DCC, it is possible to sequentially esterify 2‐mercaptoethanol to form unsymmetrical diesters.
The simultaneous separation and quantitation of human milk lipids
Authors: Collins Sarah E. , Jackson Marjorie B. , Lammi‐Keefe Carol J. , Jensen Robert G.
Published: November 2006

A protocol using a dry column method was modified for the extraction of total lipids and the simultaneous separation and quantitation of neutral and polar lipids in human milk. The triacylglycerol, cholesterol, phospholipid and vitamin E contents of the lipid extracts were determined and compared with lipids extracted using a modified Folch procedure. Good precision for the extraction of neutral, polar and total lipids, as well as the different lipid classes, was demonstrated. No significant differences were found between the two methods with respect to the amount of cholesterol, phospholipid, total lipid or vitamin E extracted, thus validating the method as an extraction technique. We discuss the relationship between vitamin E and the three major milk lipids as an indicator of the vitamin's place of origin in the mammary gland. Our findings do not support the idea that vitamin E in mature milk has its original location in the apical membrane.
Effects of dietary casein and soy protein on metabolism of radiolabelled low density apolipoprotein B in rabbits
Authors: Samman Samir , Khosia Pramod , Carroll Kenneth K.
Published: November 2006

Rabbits fed semipurified diets containing casein have elevated plasma cholesterol levels compared to those fed soy protein. As part of continuing studies on the mechanism of casein‐induced hypercholesterolemia, two groups of six rabbits were fed these diets for 14 to 16 weeks. Animals fed the casein diet were found to have significantly higher plasma concentrations of protein, cholesterol, triacylglycerol, phospholipid and apolipoprotein B (apo B) associated with low density lipoprotein (LDL) than those fed the soy protein diet. Kinetic studies showed that the fractional catabolic rate of LDL‐apo B was significantly lower in animals fed casein than in those fed soy protein regardless of whether the tracer LDL was obtained from donors fed casein or soy protein. The production rate of LDL‐apo B was higher in casein‐fed animals but this was not statistically significant. These results show that the efficiency of removal of LDL is significantly reduced in animals fed casein compared to those fed soy protein, and that the source of LDL did not affect the efficiency of its subsequent removal. The acumulation of LDL in casein‐fed animals is consistent with down‐regulation of the LDL receptor.
In vivo incorporation of lauric acid into rat adipose tissue triacylglycerols
Authors: Bugaut Maurice
Published: November 2006

An in vivo approach was taken to examine fatty acid esterification in adipose tissue using a coconut oilenriched diet. Rats were fed a diet containing cocounut oil (50% lauric acid) for six weeks. Triacylglycerols from perirenal adipose tissue were fractionated by silver nitrate‐thin layer chromatography and, then, preparative gas chromatography. The distribution of 169 triacylglycerol types accounting for 97% of total triacylglycerols was determined. There was evidence for a very high content of mixed triacylglycerols composed of intermediate (12∶0 and 14∶0) and long acyl moieties. No significant differences were observed between the experimental distribution of triacylglycerol types and the random distribution, calculated from the total fatty acid composition. This indicated that most long chain triacylglycerols stored before coconut oil feeding would have been rearranged after the six weeks of coconut oil feeding. The experimental proportion of trilauroylglycerol reached 2%, as expected from its random proportion, and the proportions of dilauroylacylglycerols were slightly higher than the random values. Present results were compared with those previously obtained from triacylglycerols of adipose tissue of rats fed a low‐fat standard diet (1,2). From our results and those of other authors, it is suggested that lauric acid is a good substrate forsn‐glycero‐3‐phosphate acyltransferase and diacylglycerol acyltransferase in rat adipose tissue.
Effects of cholesterol oxidation derivatives on cholesterol esterifying and cholesteryl ester hydrolytic enzyme activity of cultured rabbit aortic smooth muscle cells
Authors: Morin Robert J. , Peng Shi‐Kaung
Published: November 2006

The effects of 5 μg/ml of 25‐hydroxycholesterol; cholestane‐3β, 5α,6β‐triol; and cholesterol on acyl CoA cholesterol acyltransferase, acid cholesteryl ester hydrolase and neutral cholesteryl ester hydrolase was studied in cultured rabbit aortic smooth muscle cells. After 1 hour incubation, 25‐hydroxycholesterol resulted in a fourfold stimulation of acyl CoA cholesterol acyltrans‐ferase activity. No stimulation by 25‐hydroxycholesterol was noted before 15 minutes or after 5 hours of incubation. Neither cholestane‐3β,5α,6β‐triol nor cholesterol influenced acyl CoA cholesterol acyltransferase activity at any time interval. No significant effects of any of the sterols were noted on acid cholesteryl ester hydrolase or neutral cholesteryl ester hydrolase activity. The imbalance between acyl CoA cholesterol acyl trans‐ferase and hydrolase activities induced by 25‐hydroxycholesterol could result in cholesteryl ester accumulation by arterial smooth muscle cells, which may be associated with atherosclerosis.
An improved procedure for bile acid extraction and purification and tissue distribution in the rat
Authors: Locket Patricia L. , Gallaher Daniel D.
Published: November 2006

Two bile acid extraction procedures were compared using endogenously radiolabeled tissues and feces. The method of Setchell et al. (J. Lipid Res. 24, 1085–1100, 1983) resulted in essential complete extraction, whereas that of Manes and Schneider (J. Lipid Res. 6, 376–377, 1971) gave recoveries between 56–82%. The time requirement for the method of Setchell et al. could be drastically reduced with no loss in extraction efficiency. Using extracts from endogenously labeled material, a purification procedure using C18 solid‐phase extraction cartridges was developed that recovers >90% of bile acids. The distribution of bile acids within the intestinal tract and liver of the rat was determined.
Comparative study of methods for measuring cholesterol in biological fluids
Authors: Cheillan Franck , Lafont Huguette , Termine Elise , Hamann Yolande , Lesgards Guy
Published: November 2006

A method combining enzymatic and electrochemical detection of cholesterol in biological fluids was compared with conventional detection methods: two chromatographic methods—gas chromatography or high performance liquid chromatography—and two enzymatic methods with colorimetric detection either by kinetic measurement or at the end of the reaction. For serum, enzymatic determination is accurate with both colorimetric detection methods; but for bile, colorimetric detection is difficult to perform due to interference from bile pigments. Enzymatic cholesterol determination, combined with electrochemical detection, is simpler and gives results in good agreement with those of chromatographic methods.
Very low density lipoprotein secretion by cultured hepatocytes of rabbits fed purified or autoxidized cholesterol
Authors: Kosykh Vladimir A. , Lankin Vadim Z. , Podrez Eugeniy A. , Novikov Dmitriy K. , Volgushev Sergey A. , Victorov Alexander V. , Repin Vaddim S. , Smirnov Vladimir N.
Published: November 2006

The main objectives of this study were to compare the effects of dietary commercial cholesterol (containing 5% of oxidized cholesterol derivatives) and purified cholesterol on the secretion rate of very low density lipoprotein apolipoproteins and lipids by cultured rabbit hepatocytes and to verify the hypothesis that products of cholesterol autoxidation stimulate the rapid development of hypercholesterolemia. Rabbits fed dietary (old) commercial cholesterol for six weeks showed a fivefold increase in the serum concentration of cholesterol compared with that in purified cholesterol‐fed rabbits. The secretion rates of very low density lipoprotein total protein and very low density lipoprotein [3H]apolipoproteins were similar for the hepatocytes of these two cholesterol‐fed groups of animals and were two‐ and threefold greater, respectively, than for cells from control rabbits. Cholesteryl ester content of the hepatocytes from dietary (old) commercial cholesterol‐fed rabbits was dramatically increased in comparison with hepatocytes from control and purified cholesterol‐fed rabbits. The elevated intracellular cholesteryl ester content is assumed to account for such an increase of very low density lipoprotein‐cholesteryl ester secretion by cells prepared from dietary (old) commercial cholesterol‐fed rabbits. These effects appear to be caused by activation of cholesterol esterification by oxidized cholesterol derivatives. The rapid development of hypercholesterolemia induced by dietary (old) commercial cholesterol is associated, at least in part, with the stimulated production of hepatic very low density lipoprotein apolipoproteins and cholesteryl esters.
Effect of marginal zinc deficiency on lipoprotein lipase activities in postheparin plasma, skeletal muscle and adipose tissues in the rat
Authors: Koo Sung I. , Lee Christine C.
Published: November 2006

The activities of lipoprotein lipase in postheparin plasma, retroperitoneal adipose and gastrocnemius muscle tissues were determined in the rats fed 2.8 ppm of dietary zinc for eight weeks, as compared with pair‐fed and ad libitumfed rats given 30.8 ppm of zinc. The postheparin lipoprotein lipase activity, as determined by using a lipid emulsion labeled with [3H]triolein as the substrate, was significantly lower in the first group of rats, relative to that in the second and third groups. Tissue lipoprotein lipase activities were compared using the lipid emulsion and activator serum obtained from the zinc‐deficient rats and the ad libitum‐fed rats. The activator sera were devoid of very low density and low density lipoproteins, but enriched in high density lipoproteins. Muscle lipoprotein lipase activities were significantly lower when assayed with the activator serum from the zinc‐deficient compared with the activities determined with the activator serum from the ad libitum‐fed. Similarly, muscle lipoprotein lipase activities were lower in all groups when [3H]‐triolein‐labeled chylomicrons from the zinc‐deficient were used as the substrate, compared with the activities determined using the chylomicrons from the ad libitum‐fed. Lipoprotein lipase activities in the adipose tissues were not affected by the different sources of the activator sera and chylomicrons. The results strongly suggest that the decrease in postheparin lipoprotein lipase activity in zinc deficiency is not due to changes in tissue lipoprotein lipase enzyme per se, but to compositional alterations in with regard to C apolipoproteins, modulators of lipoprotein lipase activity.
Bradykinin‐increased phospholipid deacylation‐reacylation in rat renal medulla is inhibited by dBc AMP
Authors: Sterin‐Speziale Norma , Kahane Verónica L. , Setton Clara P. , Speziale Emir H.
Published: November 2006

The effect of bradykinin on the mobilization of arachidonic acid was analyzed separately by acylation and degradation.

Acylating activity was determined by the incorporation of [14C]arachidonic acid into the phospholipids at different times. Different concentrations of bradykinin had no effect on the phospholipid acylating activities.

The degradation of the phospholipids was performed on renal medullary slices prelabeled with [14C]arachidonic acid. Treatment with bradykinin produced an initial degradation of phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, with a concomitant increase in lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylinositol within 5 min of incubation. Phosphatidylcholine‐, phosphatidylethanolamine‐and phosphatidylinositol‐labeling increased thereafter and reached the control values after 10 min of incubation.

After 30 min, incubation of prelabeled slices with bradykinin produced a significant concentration‐dependent increase in the phospholipid‐labeling by reutilization of [14C]arachidonic acid.

The effect of bradykinin on the phospholipid‐labeling was blocked by preincubation with increasing concentrations of dBc AMP.

Mepacrine also blocked the bradykinin stimulation in phosphatidylcholine and phosphatidylethanolamine, but had no effect on bradykinin‐induced changes in the phosphatidylinositol arachidonic acid moiety.
Dietary induction of cholesterol gallstones in hamsters from three different sources
Authors: Cohen Bertram I. , Matoba Naoyuki , Mosbach Erwin H. , McSherry Charles K.
Published: November 2006

Cholesterol gallstones were produced in young male, golden Syrian hamsters, obtained from three different suppliers, by administering a nutritionally adequate, semipurified diet for periods of either 5 or 10 weeks. The major components of the lithogenic diet were casein, cornstarch, butterfat, corn oil and 0.3% cholesterol. The hamsters were obtained from Sesco, Harlan Sprague‐Dawley (Engle hamster) and Charles River (Lakeview hamster). There were profound differences among the three groups with respect to gallstone formation and cholesterol metabolism: The highest incidence of gallstones occurred in Sesco hamsters, 44.4% and 63.6% after 5 and 10 weeks on the lithogenic diet, respectively. In the Engle hamster, after a 5‐week feeding, cholesterol crystals and gallstones were absent. When the feeding period was extended to 10 weeks, cholesterol gallstones were present in 45.5% of the animals. In the Lakeview hamsters, neither gallstones nor cholesterol crystals were found in the gallbladder after a 5‐week period. After 10 weeks, cholesterol gallstones were found in only a single hamster. In all groups, the lithogenic diet produced large increases of liver, serum and biliary cholesterol concentrations and increased liver weights. When the animals were fed for 5 weeks, only the bile of Sesco hamsters became supersaturated. Supersaturated bile was induced in all groups after a 10‐week feeding of the lithogenic diet with cholesterol saturation ranging from 1.47 to 1.97. These data indicate that it is possible to induce cholesterol gallstones in hamsters by means of a nutritionally adequate, semipurified diet of moderate cholesterol content. The source of the animals appears to be an important variable, because there were significant differences among the hamsters of differing origins, in cholesterol metabolism and rates of gallstone formation.
Determination of ethane and pentane in free oxygen radical‐induced lipid peroxidation
Authors: Pitkänen O. M. , Hallman M. , Andersson S. M.
Published: November 2006

It has been proposed that ethane and pentane reflect free oxygen radical‐induced lipid peroxidation. However, methodological difficulties limit the use of these gases for assessment of free oxygen radical activity. In the present report we describe an improved method for the accurate analysis of picomole quantities (≥1 pmol) of ethane and pentane. They are first quantitatively trapped into an adsorbent and then heat‐desorbed directly into a capillary column for gas chromatographic quantitation. During oxidation of linolenic (n−3) and linoleic (n−6) acid, ethane and pentane were formed, respectively. Nonstimulated granulocytes formed pentane. Upon addition of phorbol 13‐myristate 12‐acetate, the generation of pentane was increased by 540%. Addition of superoxide dismutase plus catalase inhibited lipid peroxidation in both a cell‐free system and in isolated cells.

The present method is useful in the evaluation of free oxygen radical induced damage.