bluuebunny/crossref_metadata_2025 huggingface dataset:
Psyllium, not pectin or guar gum, alters lipoprotein and biliary bile acid composition and fecal sterol excretion in the hamster
Authors: Trautwein Elke A. , Rieckhoff Dörte , Kunath‐Rau Angelika , Erbersdobler Helmut F.
Published: November 2006

Different soluble dietary fibers known to alter cholesterol metabolism were fed to golden Syrian hamsters, and their specific impact on lipoproteins, biliary bile acid profile, and fecal sterol excretion was evaluated. Semipurified diets containing 20% fat; 0.12% cholesterol; and 8% of psyllium (PSY); high (hePE) and low (lePE) esterified pectin; or high (hvGG) and low (lvGG) viscous guar gum were fed for 5 wk. Compared to control, PSY caused a significant reduction in plasma cholesterol (2.9±0.5 vs. 5.5±0.5 mmol/L), whereas hePE, lePE, hvGG, or lvGG had no apparent effect on plasma lipids. Hepatic total and esterified cholesterol were substantially decreased with PSY, pectin and guar gum, whereby PSY produced the most pronounced effect. Distinctive changes existed in the bile acid profile related to the different fibers. In contrast to pectin and guar gum, PSY caused a significant increase in the cholate:chenodeoxycholate and the glycine:taurine conjugation ratio. Pectin and guar gum did not alter daily fecal neutral sterol excretion while PSY caused a 90% increase due to a higher fecal output. Daily fecal bile acid excretion and total fecal bile acid concentration were significantly increased by PSY, whereas hePE, lePE, hvGG, and lvGG revealed no or only minor effects. Taken together, the disparate hypocholesterolemic effects of PSY, pectin, and guar gum on cholesterol and bile acid metabolism in the hamster are possibly related to different physicochemical properties, e.g., viscosity and susceptibility to fermentation, affecting the fiber‐mediated action in the intestine.
Mechanism of lower oxidizability of eicosapentaenoate than linoleate in aqueous micelles. II. Effect of antioxidants
Authors: Yazu Kazumasa , Yamamoto Yorihiro , Niki Etsuo , Miki Keiji , Ukegawa Koji
Published: November 2006

We have reported that the peroxyl radicals derived from methyl eicosapentaenoate (20:5n‐3) are more polar than those from methyl linoleate (18:2n‐6) since the former peroxyl radicals have at least two molecules of oxygen in a molecule while the latter peroxyl radical has one. This lowers the oxidizability for 20:5n‐3 in aqueous Triton X‐100 micelles by enhancing the termination reaction rate for peroxyl radicals and by reducing the rate of propagation since there may be more polar peroxyl radicals derived from 20:5n‐3 at the surface than within the micelle core. In this study, we measured the effect of three antioxidants, di‐tert‐butyl‐4‐methylphenol (BHT), 2,2,5,7,8‐pentamethyl‐6‐chromanol (PMC) and 2‐carboxy‐2,5,7,8‐tetramethyl‐6‐chromanol (Trolox), on the oxidation of lipids in aqueous micelle. Antioxidants give a clear induction period during oxidation of 18:2n‐6 initiated with a water‐soluble radical initiator, and its induction length decreases in the order of BHT>PMC>Trolox. This is consistent with the proposed location of three antioxidants: being in the core of micelle, at the surface, or in aqueous phase, respectively. However, BHT does not inhibit the oxidation of 20:5n‐3 efficiently, and its rate of oxidation is slower than that observed in the oxidation of 18:2n‐6, supporting the idea that polar peroxyl radicals derived from 20:5n‐3 are preferentially located at the surface of the micelle. Similar results were obtained when oxidation was initiated with a lipid‐soluble radical initiator except antioxidants had lesser effect on the oxidation rate of 20:5n‐3.
Partial purification and characterization of sphingosine N‐acyltransferase (ceramide synthase) from bovine liver mitochondrion‐rich fraction
Authors: Shimeno Hiroshi , Soeda Shinji , Sakamoto Masahiko , Kouchi Takeshi , Kowakame Takashi , Kihara Taro
Published: November 2006

Sphingosine N‐acyltransferase (ceramide synthase, E.C. 2.3.1.24) was solubilized from bovine liver mitochondrion‐rich fraction with n‐ocytl β‐d‐thioglucoside as the detergent and partially purified by sequential chromatography on columns of DE‐32, shingosine affinity, and Sepharose CL‐6B. The partially purified preparation migrated on SDS‐polyacrylamide gel electrophoresis as two major protein bands of 62 and 72 kDa. The molecular mass of the enzyme estimated by gel filtration was 240–260 kDa, suggesting that the partially purified enzyme is present in a subunit form or simply has an aggregative nature. The specific activity of the final preparation for the condensation of sphingosine with stearoyl‐CoA increased by 98.7‐fold compared with the starting material. The optimal pH value for the ceramide synthesis was 7.5. The partially purified enzyme had an apparent Km of 146 μM and a Vmax of 11.1 nmol/min/mg protein for stearoyl‐CoA. The Km and Vmax values toward sphingosine were 171 μM and 11.3 nmol/min/mg protein, respectively. Interestingly, sphinganine was also a good substrate for this enzyme, and the Km and Vmax values were 144 μM and 8.5 nmol/min/mg protein, respectively.
Fatty acid composition of bacteria associated with the toxic dinoflagellate Ostreopsis lenticularis and with caribbean Palythoa species
Authors: Carballeira Néstor M. , Emiliano Anastacio , Sostre Anthony , Restituyo José A. , González Ileana M. , Colon Gretchen M. , Tosteson Carmen G. , Tosteson Thomas R.
Published: November 2006

The fatty acid composition of a Pseudomonas sp. (Alteromonas) and its host, the dinoflagellate Ostreopsis lenticularis, vectors in ciguatera fish poisoning, has been studied. The major fatty acids in O. lenticularis were 16∶0, 20∶5n‐3, and 22∶6n‐3, but 18∶2n‐6, 18∶3n‐3, and 18∶n‐3 were also identified. In contrast to other dinoflagellates, 18∶5n‐3 was not detected in O. lenticularis. Even‐chain fatty acids such as 9–16∶1, 11–18∶1, and 13–20∶1 predominated in the Pseudomonas sp. from O. lenticularis, but 16–20% of (E)‐11‐methyl‐12‐octadecenoic acid was also identified. The chirality of the latter was confirmed by total synthesis (28% overall yield) starting from oxacyclotridecan‐2‐one. The fatty acid compositions of two other Pseudomonas species, from the palytoxin‐producing zoanthids Palythoa mamillosa and P. caribdea, were also studied and were similar to that of the Pseudomonas sp. from O. lenticularis. The possibility of using some of these fatty acids as chemotaxonomic lipids in identifying marine animals that consume toxic dinoflagellates or zoanthids is discussed.
Effect of the degree of hydrogenation of dietary fish oil on the trans fatty acid content and enzymatic activity of rat hepatic microsomes
Authors: Morgado Nora , Galleguillos Angélica , Sanhueza Julio , Garrido Argelia , Nieto Susana , Valenzuela Alfonso
Published: November 2006

The degree of fat hydrogenation and the trans fatty acid content of the diet affect the fatty acid composition of membranes, and the amount and the activity of some membrane enzymes. We describe the effects of four isocaloric diets containing either sunflower oil (SO, 0% trans), fish oil (FO, 0.5% trans), partially hydrogenated fish oil (PHFO, 30% trans), or highly hydrogenated fish oil (HHFO, 3.6% trans) as fat sources on the lipid composition and the trans fatty acid content of rat hepatic microsomes. We also describe the effect of these diets on the cytochrome P‐450 content and on the aminopyrine N‐demethylase, aniline hydroxylase, and UDP‐glucuronyl transferase microsomal activities. Cytochrome P‐450 content was dependent on the degree of unsaturation of the diet, being higher for the FO‐containing diet and lower for the HHFO diet. Aminopyrine N‐demethylase activity also correlated with the degree of unsaturation of the diet as did the cytochrome P‐450 content did (FO>SO>PHFO>HHFO). Aniline hydroxylase activity appeared to be independent of the degree of unsaturation of the dietary fat, but correlated with the trans fatty acid content of the diet, which was also reflected in the trans content of the microsomal membranes. UDP‐glucuronyl transferase activity was higher for the FO‐containing diet than for the SO diet, showing intermediate values after the PHFO and HHFO diets.
Cyclic fatty acid monomers from dietary heated fats affect rat liver enzyme activity
Authors: Lamboni Courdjo , Sébédio Jean‐Louis , Perkins Edward G.
Published: November 2006

This study was conducted to investigate the effects of dietary cyclic fatty acid monomers (CFAM), contained in heated fat from a commercial deep‐fat frying operation, on rat liver enzyme activity. A partially hydrogenated soybean oil (PHSBO) used 7 d (7‐DH) for frying foodstuffs, or 0.15% methylated CFAM diets was fed to male weanling rats in comparison to a control group fed a nonheated PHSBO (NH) diet in a 10‐wk experiment. All diets were isocaloric with 15% fat. Animals fed either CFAM or 7‐DH diets showed increased hepatic content of cytochrome (cyt.) b5 and P450 and increased activity of (E.C. 1.6.2.4) NADPH‐cyt. P450 reductase in comparison to the control rats. In addition, the activities of (E.C. 2.3.1.21) carnitine palmitoyltransferase‐l and (E.C. 1.1.1.42) isocitrate dehydrogenase were significantly decreased when compared to that of rats fed the NH diet. A significantly depressed activity of (E.C. 1.1.1.49) glucose 6‐phosphate dehydrogenase was also observed for these animals compared to the control rats fed NH diet. Moreover, liver and microsomal proteins were significantly increased when CFAM or 7‐DH diets were fed to animals in comparison to controls while liver glycogen was decreased significantly in experimental groups of rats. The results obtained in this study indicate that the CFAM in the diet from either synthetic sources or used fats increase the activity of liver enzyme systems that detoxify them.
Magnesium silicate treatment of dietary heated fats: Effects on rat liver enzyme activity
Authors: Perkins Edward G. , Lamboni Courdjo
Published: November 2006

In an effort to reduce the deleterious nutritional effects of oxidation products generated in heated fats, a partially hydrogenated soybean oil (PHSBO) used 7 d (7‐DH) for frying foodstuffs was obtained from a commercial deep‐fat frying operation. The used fat was treated with magnesium silicate (T‐7DH). Isocaloric diets containing 15% of either 7‐DH or T‐7‐DH fats were prepared and fed to male weanling rats for 10 wk in a pair‐feeding experiment and compared to control rats fed nonheated PHSBO (NH). Animals fed the 7‐DH diet showed higher liver enzyme cytochrome b5 and P450 activity than the T‐7DH diet compared to the NH group, suggesting a positive effect of the treatment. These results suggested the presence of lower amounts of harmful compounds in the diet containing the heated used oil which had been treated with the active adsorbent.
Distribution of α‐and γ‐tocopherols in Atlantic salmon (Salmo salar) tissues
Authors: Parazo Monina P. M. , Lall Santosh P. , Castell John D. , Ackman Robert G.
Published: November 2006

Groups of Atlantic salmon parr (mean initial weight 9.5 g) were fed three diets, the first containing no tocopherol supplement, the others supplemented with either all‐rac‐α‐tocopherol (A‐T) or RRR‐γ‐tocopherol (G‐T). Tocopherol concentrations in the liver, serum, testes, kidney, brain, gill, muscle, and perivisceral fat were measured after 36 wk. Despite a higher dietary intake of G‐T, compared to A‐T, deposition of γ‐tocopherol (γT) was less efficient than of α‐tocopherol (αT) in most tissues except in the perivisceral fat, an adipose tissue. In fish fed the G‐T diet, the γT/αT ratio was highest in the perivisceral fat and lowest in the liver, indicating that the liver is the most discriminatory organ for retaining αT as compared to γT, and the perivisceral fat is more suitable for the storage of γT. A negative correlation (P<0.01) was observed between the γT/αT ratio and the corresponding tissue phospholipid content, suggesting that γT is less efficiently deposited compared to αT in the phospholipid‐rich membranes which are presumed to be the functional site for lipid antioxidants in vivo. During restricted intake of αT, the liver and muscle exhibited the greatest reduction of this tocopherol among the tissues analyzed. The presence of minimal αT in the muscle from fish fed the tocopherol‐unsupplemented diet led to greater susceptibility to lipid peroxidation after frozen storage than was the case for muscle containing higher concentrations of either αT or γT. However, both αT and γT were effective stabilizers of salmon muscle lipids during frozen storage.
Cholesterol oxidation in meat from chickens fed α‐tocopherol‐and β‐carotene‐supplemented diets with different unsaturation grades
Authors: Maraschiello C. , Esteve E. , García Regueiro J. A.
Published: November 2006

The production of B‐ring and side‐chain oxysterols was evaluated in meat from chickens fed diets differing by the kind of oil or fat added. The effect of supplementary levels of natural antioxidants, as α‐tocopherol and β‐carotene, on the meat cholesterol oxidative stability was also studied. Lard, sunflower and olive oil were used as dietary fat. Raw and cooked meats were analyzed for oxysterols, and cholesterol was also quantified. Oxysterol analyses were carried out by combining the use of solid‐phase extraction, thin‐layer chromatography, capillary gas chromatography, and capillary gas chromatography‐mass spectrometry. Oxysterols were detected within the 0.1–0.5 μg/g range in raw meat. Cooking increased the oxysterol content of the meat, and levels as high as 5 μg/g muscle tissue were observed. B‐Ring oxysterols were mainly produced: the α‐and the β‐epoxycholesterols, the 7α‐and 7β‐hydroxycholesterols, and the 7‐ketocholesterol. The results showed that the meat from the chickens fed the olive oil‐based diet containing α‐tocopherol at 200 mg/kg of diet presented the best cholesterol oxidative stability. A positive effect could not be found for dietary β‐carotene administered at levels of 15 and 50 mg/kg of diet. Furthermore, a significant decrease in the tissue cholesterol content was observed with the olive and the sunflower oil‐based diets.
Tanacetum (Chrysanthemum) corymbosum seed oil—A rich source of a novel conjugated acetylenic acid
Authors: Tsevegsuren Nanzad , Christie William W. , Lösel Dorothy
Published: November 2006

A new conjugated trans,trans‐diunsaturated acetylenic acid (17%), found for the first time in nature as a main component of the seed oil of Tanacetum (Chrysanthemum) corymbosum, was shown to be octadeca‐8t,10t‐dien‐12‐ynoic acid. Another already known naturally occurring acetylenic acid, crepenynic acid (10%), was found also in the seed oil. The structure of this new unusual fatty acid was confirmed by chromatographic (thin‐layer chromatography, gas chromatography, high‐performance liquid chromatography) and spectroscopic (infrared, ultraviolet, mass spectrometry) methods by using different chemical derivatizations (deuteration, preparation of picolinyl ester, dimethyloxazoline, and maleic anhydride adduct).
Fullerene lipids: Synthesis of dialkyl 1,2‐[6,6]‐methano‐[60]‐fullerene dicarboxylate derivatives
Authors: Lie Ken Jie Marcel S. F. , Cheung Sunny Wai‐Hung
Published: November 2006

Reaction of C60 fullerene with dialkyl bromomalonate (where the alkyl groups consist of short‐, medium‐, and long‐saturated chains or unsaturated long chains) in the presence of sodium hydride gives [6,6]‐bridged mono‐adducts of methanofullerene. The spectroscopic properties of such fullerenoid lipids are reported.
9‐Hydroxy‐traumatin, a new metabolite of the lipoxygenase pathway
Authors: Gardner Harold W.
Published: November 2006

9‐Hydroxy‐traumatin, 9‐hydroxy‐12‐oxo‐10E‐dodecenoic acid, was isolated as a product of 13S‐hydroperoxy‐9Z, 11E‐octadecadienoic acid as catalyzed by enzyme preparations of both soybean and alfalfa seedlings. This suggested that 9Z‐traumatin, 12‐oxo‐9Z‐dodecenoic acid, was being converted into 9‐hydroxy‐traumatin in an analogous manner to the previously identified enzymic conversion of 3Z‐nonenal and 3Z‐hexenal into 4‐hydroxy‐2E‐nonenal and 4‐hydroxy‐2E‐hexenal, respectively. Other metabolites of 13S‐hydroperoxy‐9Z,11E‐octadecadienoic acid were similar for both soybean and alfalfa seedling preparations, and they are briefly described.
Rate constants for quenching singlet oxygen and activities for inhibiting lipid peroxidation of carotenoids and α‐tocopherol in liposomes
Authors: Fukuzawa Kenji , Inokami Yasuki , Tokumura Akira , Terao Junji , Suzuki Asahi
Published: November 2006

The 1O2 quenching rate constants (kQ) of α‐tocopherol (α‐Toc) and carotenoids such as β‐carotene, astaxanthin, canthaxanthin, and lycopene in liposomes were determined in light of the localization of their active sites in membranes and the micropolarity of the membrane regions, and compared with those in ethanol solution. The activities of α‐Toc and carotenoids in inhibiting 1O2‐dependent lipid peroxidation (reciprocal of the concentration required for 50% inhibition of lipid peroxidation: [IC50]−1) were also measured in liposomes and ethanol solution and compared with their kQ values. The kQ and [IC50]−1 values were also compared in two photosensitizing systems containing Rose bengal (RB) and pyrenedodecanoic acid (PDA), respectively, which generate 1O2 at different sites in membranes. The kQ values of α‐Toc were 2.9×108M−1s−1 in ethanol solution and 1.4×107 M−1s−1 (RB system) or 2.5×106 M−1s−1 (PDA system) in liposomes. The relative [IC50]−1 value of α‐Toc in liposomes was also five times higher in the RB system than in the PDA‐system. In consideration of the local concentration of the OH‐group of α‐Toc in membranes, the kQ value of α‐Toc in liposomes was recalculated as 3.3×106 M−1s−1 in both the RB and PDA systems. The kQ values of all the carotenoids tested in two photosensitizing systems were almost the same. The kQ value of α‐Toc in liposomes was 88 times less than in ethanol solution, but those of carotenoids in liposomes were 600–1200 times less than those in ethanol solution. The [IC50]−1 value of α‐Toc in liposomes was 19 times less than that in ethanol solution, whereas those of carotenoids in liposomes were 60–170 times less those in ethanol solution. There were no great differences (less than twice) in the kq and [IC50]−1 values of any carotenoids. The kQ values of all carotenoids were 40–80 times higher than that of α‐Toc in ethanol solution but only six times higher that of α‐Toc in liposomes. The [IC50]−1 values of carotenoid were also higher than that of α‐Toc in ethanol solution than in liposomes, and these correlated well with the kQ values.
Dietary oxidized cholesterol modulates cholesterol metabolism and linoleic acid desaturation in rats fed high‐cholesterol diets
Authors: Osada Kyoichi , Kodama Takehiro , Yamada Koji , Nakamura Shingo , Sugano Michihiro
Published: November 2006

The interactive effect of high dietary levels of oxidized cholesterol on exogenous cholerterol and linoleic acid metabolism was examined in male 4‐wk‐old Sprague‐Dawley rats given high‐cholesterol diets. The rats were pair‐fed purified diets free of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing 93% oxidized cholesterol) for 3 wk. Hepatic 3‐hydroxy‐3‐methylglutaryl CoA reductase activity was reduced in rats given cholesterol alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7α‐hydroxylase activity was lowered only when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the other hand, the activity of hepatic Δ6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity. As a result, the Δ6 desaturation index, 20∶3n‐6+20∶4n‐6/18∶2n‐6, in liver and serum phosphlipids tended to be higher in the group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at high levels together with a high cholesterol diet.
The cholesterol‐lowering effect of guar gum in rats is not accompanied by an interruption of bile acid cycling
Authors: Favier Marie‐Laure , Bost Pierre‐Etienne , Demigné Christian , Rémésy Christian
Published: November 2006

A viscous hydrocolloid (guar gum, GG; 2.5% of the diet) or a steroid sequestrant (cholestyramine; 0.5% of the diet) was included in semipurified diets containing 0.2% cholesterol to compare the cholesterol‐lowering effects of each agent in rats. In the present model, GG significantly lowered plasma cholesterol (−25%), especially in the density <1.040 kg/L fraction, whereas cholestyramine was less potent. Bile acid fecal excretion significantly increased only in rats fed cholestyramine, similar to the cecal bile acid pool; the biliary bile acid secretion was accelerated by GG, but not their fecal excretion, whereas GG effectively enhanced neutral sterol excretion. As a result, the total steroid balance (+13 μmol/d in the control) was shifted toward negative values in rats fed the GG or cholestyramine diets (−27 or −50 μmol/d, respectively). Both agents induced liver 3‐hydroxy‐3‐methylglutaryl‐CoA reductase, but cholestyramine was more potent than GG in this respect. The present data suggest that, at a relative low dose in the diet, GG may be more effective than cholestyramine in lowering plasma cholesterol by impairing cholesterol absorption and by accelerating the small intestine/liver cycling of bile acids, which is interestingly, accompanied by reduction of bile acid concentration in the large intestine.
Surface composition regulates clearance from plasma and triolein lipolysis of lipid emulsions
Authors: Arimoto Itaru , Matsumoto Chizuko , Tanaka Masafumi , Okuhira Keiichirou , Saito Hiroyuki , Handa Tetsurou
Published: November 2006

Sphingomyelin (SM) and cholesterol (Chol) are major surface lipid constituents of plasma lipoproteins. We investigated the effects of SM and Chol on the plasma clearance of lipid emulsions as a model for lipoprotein particles in rats. The presence of Chol facilitated the removal of emulsion particles from plasma, whereas SM delayed particle removal. Preinjection of lactoferrin, an inhibitor of the apolipoprotein E (apoE) receptor, revaled that the differences in clearance of emulsions were due to the differences in affinity for the apoE receptor. Measurement of apolipoprotein binding suggested that the balance of apoE and apoC (apoC‐II and apoC‐III) bound to emulsions caused the difference in plasma clearance of emulsion particles. That is to say, SM in the emulsion surface decreased binding of apoE, which led to a longer circulation of emulsion particles in plasma. Chol, on the other hand, decreased the ratio of apoC to apoE, which may have promoted emulsion uptake through the apoE receptor. We also examined in vitro lipolysis using immobilized lipoprotein lipase (LPL) in a heparin affinity column. Lipolysis rates were significantly reduced by the incorporation of SM into the emulsion surface, but not by the incorporation of Chol, indicating that SM in the lipoprotein surface is an important lipid component regulating LPL‐mediated lipolysis. Our results suggest that the presence of SM and Chol in the lipoprotein surface plays an important role in the circulation behavior and LPL‐mediated lipolysis of lipid emulsions through their effect on the selectivity of plasma protein binding.
Remodeling of phospholipid fatty acids in mitochondrial membranes of estivating snails
Authors: Stuart J. A. , Gillis T. E. , Ballantyne J. S.
Published: November 2006

The effects of estivation on the phospholipid‐specific fatty acid composition of mitochondrial membranes in the hepatopancreas of the terrestrial snail Cepaea nemoralis were investigated. The fatty acid composition of all phospholipids was significantly altered in snails estivating for 6 wk, indicating that substantial remodeling occurs. The most profound changes occurred in cardiolipin (CL). CL of estivating snails was 13‐fold more saturated, contained 9‐fold more monoenes, and had 45% fewer polyenes than in active snails. These differences were due, in part, to a reduction in linoleic acid (18:2n‐6) content of CL from estivators. As in mammals, CL of active snails appears to preferentially incorporate 18:2n‐6, which accounts for 60% of the acyl chains in this phospholipid. This proportion was reduced by 50% in estivators. Changes in the fatty acyl content of other phospholipids of estivating snails included increased monoenes in phosphatidylethanolamine (PE) and phosphatidylinositol, reduced ratios of n‐3/n‐6 polyenes in PE and phosphatidylcholine (PC), and an increased n‐3/n‐6 ratio in phosphatidylserine (PS). Arachidonic acid (20:4n‐6) levels were reduced in PS but increased in CL and PC. Taken together, these alterations to fatty acid composition are consistent with decreased biological activity of membrane‐related processes which occur in conjunction with the reduction of mitochondrial aerobic metabolism observed during estivation.
Changes in tissue polyunsaturated fatty acids with age, in spontaneously hypertensive rats
Authors: Delachambre Marie‐Claire , Narce Michel , Asdrubal Philippe , Poisson Jean‐Pierre
Published: November 2006

The relationship between the biosynthesis of long‐chain fatty acids and their distribution in the key organs of hypertension is of considerable interest because of their role in the production of vasoactive eicosanoids and their effects on membrane properties. The present study analyzed the fatty acid compositions of the total lipids in the kidney, aorta, heart, and hepatocytes of 1‐, 3‐, and 6‐mon‐old spontaneously hypertensive rats (SHR) and their normotensive controls, Wistar Kyoto rats (WKY) by capillary gas chromatography. The major changes concerned the polyunsaturated fatty acids (PUFA). The percentage of arachidonic acid (AA) was significantly greater in the 1‐mon‐old SHR kidney than in the WKY kidney, but it was lower at 3 and 6 mon. The percentage of eicosapentaenoic acid was very low in the SHR kidney. The results for the aorta were similar, with marked decreases in 18:2n−6 and 18:3n−3 in SHR aged 1 and 6 mon. Despite a higher proportion of 18:2n−6 and AA at 6 mon, there was no major change in the SHR heart lipids. The fatty acid spectrum in the liver provides additional evidence for the previously reported inhibition of desaturase activities in SHR. Thus, this study shows that the PUFA composition is modified differently in different tissues in SHR, and this may be related to the pathogenesis of hypertension in these animals.
A new conjugated linoleic acid isomer, 7 trans, 9 cis‐octadecadienoic acid, in cow milk, cheese, beef and human milk and adipose tissue
Authors: Yurawecz Martin P. , Roach John A. G. , Sehat Najibullah , Mossoba Magdi M. , Kramer John K. G. , Fritsche Jan , Steinhart Hans , Ku Youh
Published: November 2006

The identity of a previously unrecognized conjugated linoleic acid (CLA) isomer, 7 trans, 9 cis‐octadecadienoic acid (18∶2) was confirmed in milk, cheese, beef, human milk, and human adipose tissue. The 7 trans, 9 cis‐18∶2 isomer was resolved chromatographically as the methyl ester by silver ion‐high‐performance liquid chromatography (Ag+‐HPLC); it eluted after the major 9 cis, 11 trans‐18∶2 isomer (rumenic acid) in the natural products analyzed. In the biological matrices in‐vestigated by Ag+‐HPLC, the 7 trans, 9 cis‐18∶2 peak was generally due to the most abundant minor CLA isomer, ranging in concentration from 3 to 16% of total CLA. By gas chromatography (GC) with long polar capillary columns, the methyl ester of 7 trans, 9 cis‐18∶2 was shown to elute near the leading edge of the major 9 cis, 11 trans‐18∶2 peak, while the 4,4‐dimethyloxazoline (DMOX) derivative permitted partial resolution of these two CLA isomers. The DMOX derivative of this new CLA isomer was analyzed by gas chromatography‐electron ionization mass spectrometry (GC‐EIMS). The double bond positions were at Δ7 and Δ9 as indicated by the characteristic mass spectral fragment ions at m/z 168, 180, 194, and 206, and their allylic cleavages at m/z 154 and 234. The cis/trans double‐bond configuration was established by GC‐direct deposition‐Fourier transform infrared as evidenced from the doublet at 988 and 949 cm−1 and absorptions at 3020 and 3002 cm−1. The 7 trans, 9 cis‐18∶2 configuration was established by GC‐EIMS for the DMOX derivative of the natural products examined, and by comparison to a similar product obtained from treatment of a mixture of methyl 8‐hydroxy‐and 11‐hydroxyoctadec‐9 cis enoates with BF3, in methanol.
Analysis of ubiquinone and tocopherol levels in normal and hyperlipidemic human plasma
Authors: Zhang Yiyi , Eriksson Mats , Dallner Gustav , Appelkvist Eeva‐Liisa
Published: November 2006

The type and amount of lipophilic antioxidants in plasma of hyperlipidemic patients are of great importance since they play a central role in preventing deleterious oxidation of blood lipids and proteins. Isolation and quantitation of lipophilic antioxidants from hyperlipidemic plasma samples meet great obstacles because of increased levels of various intermediary lipid products. This study was designed to develop a rapid and efficient extraction and separation procedure for simultaneous analysis of ubiquinone‐9 and‐10 as well as α‐, δ‐, and γ‐tocopherol isomers. The levels of ubiquinone‐10, α‐ and γ‐tocopherol were analyzed in human plasma samples using high‐performance liquid chromatography. Lipid extraction was performed by petroleum ether/methanol/water. After phase separation, ubiquinone was reduced to ubiquinol by sodium borohydride and the lipids were separated on a C18 column. A binary gradient with solvents containing lithium perchlorate was used, and an electrochemical detector was employed for quantitation. This procedure was also efficient for the analysis of antioxidant lipids in samples containing a large number of accumulated and interfering lipid intermediates. Thus, the procedure described here is useful for efficient and rapid quantitation of ubiquinones and tocopherols in human plasma samples, especially those originating from hyperlipidemic patients.
Evidence that commercial calf and horse sera can contain substantial amounts of trans‐10,cis‐12 conjugated linoleic acid
Authors: Park Yeonhwa , Pariza Michael W.
Published: November 2006

We analyzed fetal calf, newborn calf, horse, and adult cow sera for conjugated linoleic acid (CLA). All sera samples contained CLA, but the amounts varied. The predominant isomer was cis‐9,trans‐11 CLA but some samples appeared to contain substantial amounts of an isomer with the retention time of trans‐10,cis‐12 CLA.
Lectin may contribute to the atherogenicity of peanut oil
Authors: Kritchevsky David , Tepper A. , Klurfeld David M.
Published: November 2006

Peanut oil is unexpectedly atherogenic for rats, rabbits, and primates. The lesions it produces are more fibrous than fatty. The mechanism underlying the atherogenicity of peanut oil has been elusive. Randomization of peanut oil reduces significantly its atherogenic properties, but native and randomized peanut oils have similar rates of lipolysis, and rats fed the two oils absorb and transport lipids in a similar fashion. Peanut oil differs from other oils in having a relatively high lectin content, and the randomization process markedly reduces the lectin content as well. The biologically active lectin of peanut oil has an affinity for glycoproteins found specifically on arterial smooth muscle cells. Peanut lectin has been shown to stimulate growth of smooth muscle and pulmonary arterial cells. Vigorous washing of peanut oil reduces its lectin content by 46%. Compared to rabbits fed cholesterol and peanut oil, rabbits fed cholesterol and washed peanut oil exhibited less severe atherosclerosis in the aortic arch (by 9%) and in the thoracic aorta (by 31%). The data suggest that peanut oils' endogenous lectin may contribute significantly to its atherogenic properties.
The signature 10‐hydroxy stearic acid thought to correlate with infectivity in oocysts of Cryptosporidium species is an artifact
Authors: Burkhalter Robert S. , Smith Carol A. , White David C. , Fayer Ronald , White Andrew B.
Published: November 2006

Heating or freezing leads to loss in infectivity of oocysts of Cryptosporidium parvum toward neonatal BALB/c mice and is reflected in the profile of the polar lipid fatty acids. Upon loss of infectivity, the ratio of polar lipid to neutral lipid fatty acid decreased and the relative proportions of 18∶1n‐9 also decreased; proportions of 18∶2n‐6 and 20∶5n‐6 increased, whereas the proportions of 16∶0 remained constant with freezing. During these investigations, a novel fatty acid, 10‐OH 18∶0, was discovered in the glycolipid fraction. The identification of a fatty acid unique to species of Cryptosporidium was thought to provide a specific biomarker for this organism. Cryptosporidium also demonstrated fluctuations in absolute quantities of 10‐OH 18∶0 with events that lead to loss of infectivity. This led to the presumed correlation of this biomarker with infectious Cryptosporidium. The 10‐OH 18∶0 was putatively localized at the sn‐2 position of phosphatidylethanolamine. High‐performance liquid chromatography/electrospray ionization mass spectrometry revealed that the 10‐OH 18∶0 existed principally in the free fatty acid form. Herein, we establish that the free fatty acid 10‐OH 18∶0 was, in actuality, an artifact of the procedures for sample preparation.
Analysis of novel hydroperoxides and other metabolites of oleic, linoleic, and linolenic acids by liquid chromatography‐mass spectrometry with ion trap MSn
Authors: Oliw Ernst H. , Su Chao , Skogström Torun , Benthin Günther
Published: November 2006

Linoleate is oxygenated by manganese‐lipoxygenase (Mn‐LO) to 11S‐hydroperoxylinoleic acid and 13R‐hydroperoxyoctadeca‐9Z,11E‐dienoic acid, whereas linoleate diol synthase (LDS) converts linoleate sequentially to 8R‐hydroperoxylinoleate, through an 8‐dioxygenase by insertion of molecular oxygen, and to 7S,8S‐dihydroxylinoleate, through a hydroperoxide isomerase by intramolecular oxygen transfer. We have used liquid chromatography‐mass spectrometry (LC‐MS) with an ion trap mass spectrometer to study the MSnmass spectra of the main metabolites of oleic, linoleic, α‐linolenic and γ‐linolenic acids, which are formed by Mn‐LO and by LDS. The enzymes were purified from the culture broth (Mn‐LO) and mycelium (LDS) of the fungusGaeumannomyces graminis. MS3analysis of hydroperoxides and MS2analysis of dihydroxy‐ and monohydroxy metabolites yielded many fragments with information on the position of oxygenated carbons. Mn‐LO oxygenated C‐11 and C‐13 of 18∶2n−6, 18∶3n−3, and 18∶3n−6 in a ratio of ∼1∶1–3 at high substrate concentrations. 8‐Hydroxy‐9(10)expoxystearate was identified as a novel metabolite of LDS and oleic acid by LC‐MS and by gas chromatography‐MS. We conclude that LC‐MS with MSnis a convenient tool for detection and identification of hydroperoxy fatty acids and other metabolites of these enzymes.
Characterization of phospholipase D activity in bovine photoreceptor membranes
Authors: Salvador G. A. , Giusto N. M.
Published: November 2006

Phospholipase D (E.C. 3.1.4.4.) was detected in isolated bovine rod outer segments (ROS) and its properties determined. The enzyme activity was assayed using either a sonicated microdispersion of 1,2‐diacyl‐sn‐[23H]glycerol‐3‐phosphocholine (PC), or [14C]ethanol. Using [3H]PC and ethanol as a substrate, we were able to detect the hydrolytic properties as well as the transphosphatidylation reaction catalyzed by phospholipase D (PLD): formation of [3H]phosphatidic acid and phosphatidylethanol [3H]PtdEt; whereas with [14C]ethanol or [3H]glycerol in the absence of exogenous PC, only transphosphatidylation reactions were detected (formation of [14C]PtdEt or [3H]phosphatidylglycerol, respectively). The use of varying concentrations of [3H]PC and 400 mM of ethanol gave an apparent Km value for PC of 0.51 mM and a Vmax value of 111 nmol × h−1 × (mg protein)−1. The activity was linear up to 60 min of incubation and up to 0.2 mg of protein. The optimal ethanol concentration was determined to be 400 mM, with an apparent Km of 202 mM and a Vmax value for ethanol of 125 nmol × h−1 × (mg protein)−1. A clear pH optimum was observed around 7. PLD activity was increased in the presence of 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propane‐sulfonate or sodium deoxycholate and inhibited with Triton X‐100. The enzyme activity was also activated in the presence of Ca2+ or Mg2+ (1 mM) although these ions were not required for measuring PLD activity. The high specific activity of PLD found in purified ROS compared to the activity found in other subcellular fractions of the bovine retina suggests that this enzymatic activity is native to ROS. The present report is the first evidence of PLD activity associated with photoreceptor ROS.
Lipase specificity toward some acetylenic and olefinic alcohols in the esterification of pentanoic and stearic acids
Authors: Lie Ken Jie Marcel S. F. , Fu Xun
Published: November 2006

The esterification of five medium‐ and long‐chain acetylenic alcohols (2‐nonyn‐1‐ol, 10‐undecyn‐1‐ol, 6‐octadecyn‐1‐ol, 9‐octadecyn‐1‐ol, and 13‐docosyn‐1‐ol), seven olefinic alcohols (cis‐3‐nonen‐1‐ol, 10‐undecen‐1‐ol, cis‐6‐octadecen‐1‐ol, cis‐9‐octadecen‐1‐ol, trans‐9‐octadecen‐1‐ol, trans‐9, trans‐11‐octadecadien‐1‐ol, cis‐9, cis‐12‐octadecadien‐1‐ol), and four short‐chain unsaturated alcohols (allyl alcohol, 3‐butyn‐1‐ol, 3‐pentyn‐1‐ol, and cis‐2‐penten‐1‐ol) with pentanoic or stearic acid in the presence of various lipase preparations was studied. With the exception of 2‐nonyn‐1‐ol, where Lipase AY‐30 (Candida rugosa) was used as the biocatalyst, the esterification of C11, C18, and C22 acetylenic alcohols with pentanoic acid appeared to be generally unaffected by the presence of an acetylenic bond in the alcohol as relatively high yields of the corresponding esters (78–97%) were obtained. However, medium‐ and long‐chain olefinic alcohols were discriminated by Lipase AY‐30, Lipolase 100T (Rhizomucor miehei), and especially by porcine pancreatic lipase (PPL), when esterification was conducted with pentanoic acid. Esterification of medium‐and long‐chain acetylenic or olefinic alcohols with a long‐chain fatty acid, stearic acid, was very efficient except when Lipase AY‐30 and Lipolase 100T were used. Short‐chain unsaturated alcohols were much more readily discriminated. 3‐Pentyn‐1‐ol and 3‐butyn‐1‐ol were difficult (<5% yield) to esterify with pentanoic or stearic acid in the presence of Lipase AY‐30 and PPL, respectively. Very low yields (<26%) of esters were produced when 3‐butyn‐1‐ol and 3‐pentyn‐1‐ol were reacted with pentanoic or stearic acid, when catalyzed by lipase from Candida cylindracea, No reaction took place between 3‐butyn‐1‐ol and stearic acid in the presence of Lipase AY‐30. Esterification of short‐chain acetylenic and olefinic alcohols was most efficiently achieved with Lipolase 100T (Rhizomucor miehei), Lipozyme IM20 (Rh. miehei), or Novozyme 435 (Candida antarctica) as the biocatalyst.
The triggering signal dictates the effect of docosahexaenoic acid on lymphocyte function in vitro
Authors: Jenski Laura J. , Scherer John M. , Caldwell LaDawn D. , Ney Victori A. , Stillwell William
Published: November 2006

Docosahexaenoic acid (DHA) is an n‐3 fatty acid beneficial to several human conditions including inflammation and autoimmune disease. To better understand the effect of DHA on immunity, we monitored the rise in cytosolic free calcium, interleukin 2 receptor (IL2R) expression, and proliferation of splenic lymphocytes triggered with three different stimuli in the presence or absence of DHA. We found that 10 μg DHA/mL suppressed concanavalin A‐induced mitogenesis and the mixed lymphocyte reaction while concurrently enhancing proliferation stimulated with anti‐Thy‐1 antibodies. Proliferation, as measured by [3H]thymidine incorporation after 2 to 5 d of culture, was affected by DHA, but earlier activation effects such as elevation of cytosolic free calcium and IL2R expression were not altered. These results imply that DHA incorporated into membrane phospholipids differentially affects the activity of distinct membrane‐bound receptors and signaling molecules. This result suggests that DHA may be used to modulate immune responses selectively, e.g., to suppress, undesired autoimmunity while maintaining protective immunity.
Different degrees of moderate iron deficiency modulate lipid metabolism of rats
Authors: Stangl Gabriele I. , Kirchgessner Manfred
Published: November 2006

Severe iron deficiency affects lipid metabolism. To investigate whether moderate iron depletion also alters lipid variables—including lipid levels in serum and liver, hepatic lipogenesis, and fatty acid composition indicative of an impaired desaturation—we carried out experiments with rats fed 9, 13, and 18 mg iron/kg diet over a total of 5 wk. The study also included three pair‐fed control groups and an ad libitum control group, fed with 50 mg iron/kg diet. The iron‐depleted rats were classified as iron‐deficient on the basis of reduced serum iron, hemoglobin concentration, and hematocrit. All moderately iron‐deficient rats had significantly lower cholesterol concentrations in liver and serum lipoproteins than their pair‐fed controls. Rats with the lowest dietary iron supply had higher concentrations of hepatic phosphatidylcholine (PC) and phosphatidylethanolamine (PE), lower activities of glucose‐6‐phosphate dehydrogenase, malic enzyme and fatty acid synthase, and higher triacylglycerol concentrations in serum lipoproteins than the corresponding pair‐fed control rats. Moderate iron deficiency also depressed the serum phospholipid level. Moreover, several consistent significant differences in fatty acid composition of hepatic PC and PE occurred within moderate iron deficiency, which indicate impaired desaturation by Δ‐9 and Δ‐6 desaturases of saturated and essential fatty acids. We conclude that lipid variables, including cholesterol in liver and serum lipoproteins as well as fatty acid desaturation, reflect the gradations of iron status best and can be used as an indicator of the degree of moderate iron deficiency.
Effects of dietary methionine and cystine on lipid metabolism in hepatoma‐bearing rats with hyperlipidemia
Authors: Kawasaki Masashi , Funabiki Ryuhei , Yagasaki Kazumi
Published: November 2006

Abnormal lipid metabolism and its restoration by dietary methionine (Met) and cystine (Cys) were studied in Donryu rats subcutaneously implanted with an ascites hepatoma cell line of AH109A. The hepatoma‐bearing rats exhibited byperlipidemia characterized by rises in serum triglyceride and cholesterol levels. Decreased lipoprotein lipase (LPL) activities in epididymal adipose tissue, cardiac muscle, and gastrocnemius as well as increased fatty acid mobilization from adipose tissue were considered to be responsible for the hepatoma‐induced hypertriglyceridemia, while increased hepatic cholesterogenesis and decreased steroid excretion into feces were thought to be responsible for the hepatoma‐induced hypercholesterolemia. Dietary‐supplemented Met or Cys reduced the AH109A‐induced hypertriglyceridemia with suppression of fatty acid synthesis in the host liver. Met restored the fall of LPL activities, while Cys did not. Dietary Met or Cys also reduced the hypercholesterolemia with restoration of decreased bile acid excretion into feces. These results suggest that dietary Met or Cys is hypolipidemic in the hepatoma‐bearing rats with slight differences in their modes of action.
An efficient ultrasound‐assisted zinc reduction of fatty esters containing conjugated enynol and conjugated enynone systems
Authors: Lie Ken Jie Marcel S. F. , Mustafa Jamal , Pasha Mohammed Khysar
Published: November 2006

Reduction of methyl 8‐hydroxy‐11‐E/Z‐octadecen‐9‐ynoate (1) with zinc in either aqueous n‐propanol or water under concomitant ultrasound irradiation furnished a mixture of methyl 8‐hydroxy‐9Z,11E‐octadecadienoate (3a) and methyl 8‐hydroxy‐9Z, 11Z‐octadecadienoate (3b) (96% yield). Reduction of methyl 8‐oxo‐11‐E/Z‐octadecen‐9‐ynoate (2) under similar conditions gave methyl 8‐oxo‐10‐Z‐octadecenoate exclusively (4, 70%). The latter compound was epoxidized and converted to a C18 furanoid fatty ester (6, methyl 8,11‐epoxy‐8,10‐octadecadienoate) in 70% yield.
Assessment of the arachidonic acid content in foods commonly consumed in the American diet
Authors: Taber Laura , Chiu Chun‐Hung , Whelan Jay
Published: November 2006

Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB‐8). The cooked portions were prepared as described in HB‐8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB‐8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB‐8. In contrast, the AA and n‐3 fatty acid contents in tuna were almost half the HB‐8 values. The present data indicate that HB‐8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.
Fish oil supplementation with and without added vitamin E differentially modulates plasma antioxidant concentrations in healthy women
Authors: Turley E. , Wallace J. M. W. , Gilmore W. S. , Strain J. J.
Published: November 2006

The purpose of this study was to assess the effect of fish oil with or without vitamin E on plasma vitamin antioxidants. Thirty‐three apparently healthy women aged 18–28 yr were recruited from the university environs, and 30 completed the double‐blinded, parallel design supplementation trial. Blood samples were collected at baseline (week 0) and following 28 d of supplementation with three capsules/d (0.8 g×3) of either fish oil (FO) or FO with vitamin E (3 IU/g) (FOE). An additional blood sample was taken at day 91 (washout). Plasma antioxidant vitamins, fatty acid composition, and lipid peroxides were measured. Plasma α‐tocopherol concentrations were increased significantly in both groups postsupplementation FO (P=0.018) and FOF (P=0.003) compared with baseline and washout values. Plasma retinol concentration was significantly increased (P=0.034) compared with baseline and washout values following supplementation with FOE but not FO, while plasma β‐carotene was significantly increased (P=0.036), compared with baseline and washout values, following supplementation with FO but not FOE. There was a trend (P=0.059) toward decreased plasma ascorbic acid following FO supplementation compared with baseline and washout. Plasma lipid peroxides did not change following either supplementation. Results suggest that low‐dose FO feeding with and without vitamin E differentially modulates plasma antioxidant vitamins but has no significant effect on lipid peroxidation.