bluuebunny/crossref_metadata_2025 huggingface dataset:
Eicosapentaenoic and docosahexaenoic acid affect mitochondrial and peroxisomal fatty acid oxidation in relation to substrate preference
Authors: Madsen Lise , Rustan Arild C. , Vaagenes Hege , Berge Kjetil , Dyrøy Endre , Berge Rolf K.
Published: November 2006

Decreased triacylglycerol synthesis within hepatocytes due to decreased diacylglycerol acyltransferase (DGAT) activity has been suggested to be an important mechanism by which diets rich in fish oil lower plasma triacylglycerol levels. New findings suggest that eicosapentaenoic acid (EPA), and not docosahexaenoic acid (DHA), lowers plasma triacylglycerol by increased mitochondrial fatty acid oxidation and decreased availability of fatty acids for triacylglycerol synthesis. To contribute to the understanding of the triacylglycerol‐lowering mechanism of fish oil, the different metabolic properties of EPA and DHA were studied in rat liver parenchymal cells and isolated rat liver organelles. EPA‐CoA was a poorer substrate than DHA‐CoA for DGAT in isolated rat liver microsomes, and in the presence of EPA, a markedly lower value for the triacyl[3H]glycerol/diacyl[3H]glycerol ratio was observed. The distribution of [1‐14C]palmitic acid was shifted from incorporation into secreted glycerolipids toward oxidation in the presence of EPA (but not DHA) in rat liver parenchymal cells. [1‐14C]EPA was oxidized to a much greater extent than [1‐14C]DHA in rat liver parenchymal cells, isolated peroxisomes, and especially in purified mitochondria. As the oxidation of EPA was more effective and sensitive to the CPT‐I inhibitor, etomoxir, when measured in a combination of both mitochondria and peroxisomes, we hypothesized that both are involved in EPA oxidation, whereas DHA mainly is oxidized in peroxisomes. In rats, EPA treatment lowered plasma triacylglycerol and increased hepatic mitochondrial fatty acid oxidation and carnitine palmitoyltransferase (CPT)‐I activity in both the presence and absence of malonyl‐CoA. Whereas only EPA treatment increased the mRNA levels of CPT‐I, DHA treatment increased the mRNA levels of peroxisomal fatty acyl‐CoA oxidase and fatty acid binding protein more effectively than EPA treatment. In conclusion, EPA and DHA affect cellular organelles in relation to their substrate preference. The present study strongly supports the hypothesis that EPA, and not DHA, lowers plasma triacylglycerol by increased mitochondrial fatty acid oxidation.
Effects of conjugated linoleic acid isomers on the hepatic microsomal desaturation activities in vitro
Authors: Bretillon L. , Chardigny J. M. , Grégoire S. , Berdeaux O. , Sébédio J. L.
Published: November 2006

The influence of individual conjugated linoleic acid (CLA) isomers on the Δ6 desaturation of linoleic and α‐linolenic acids and on the Δ9 desaturation of stearic acid was investigated in vitro, using rat liver microsomes. The Δ6 desaturation of 18∶2n−6 was decreased from 23 to 38% when the ratio of 9cis,11trans‐18∶2 to 18∶2n−6 increased from 0.5 to 2. The compound 10trans,12cis‐18∶2 exhibited a similar effect only at the highest concentration. The Δ6 desaturation of α‐linolenic acid was slightly affected by the presence of CLA isomers. The sole isomer to induce an inhibitory effect on the Δ9 desaturation of stearic acid was 10trans,12cis‐18∶2.
Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver
Authors: Sakono Masanobu , Miyanaga Fumiko , Kawahara Satoshi , Yamauchi Kiyoshi , Fukuda Nobuhiro , Watanabe Kazumasa , Iwata Toshio , Sugano Michihiro
Published: November 2006

The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post‐perfused liver cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA‐fed rats produced significantly more ketone bodies; and the ratio of β‐hydroxybutyrate to acetoacetate, an index of mitochondrial redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant. Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced β‐oxidation of fatty acids at the expense of esterification of fatty acid in the liver.
Effects of conjugated linoleic acid on oxygen diffusion‐concentration product and depletion in membranes by using electron spin resonance spin‐label oximetry
Authors: Yin Jun Jie , Mossoba Magdi M. , Kramer John K. G. , Yurawecz Martin P. , Eulitz Klaus , Morehouse Kim M. , Ku Yuoh
Published: November 2006

The effect of conjugated linoleic acid (CLA) on the relation between structure and function of membranes is described in this paper. Electron spin resonance (ESR) spin‐label oximetry was used in the present study to evaluate if oxygen transport and oxygen depletion were affected by incorporation of CLA instead of linoleic acid into membrane phospholipids. Specifically, 1‐stearoyl‐2(9 cis, 11 trans‐octadecadienoyl)‐phosphorylcholine (SCLAPC) was incorporated into soy plant phosphatidylcholine (soy PC) or egg yolk PC (EYPC) bilayers. The use of spin labels attached to different carbons along the fatty acid chain makes it possible to carry out structural and oximetric determinations with the same test sample. For example, the incorporation of 5 mol% SCLAPC increased the oxygen diffusion‐concentration product in soy PC or EYPC liposomes at 37°C, slightly decreased the ordering of the hydrocarbon chains at the C10 and C12 positions (in the region of the conjugated double bonds), and increased the rate of oxygen depletion from the aqueous medium. Similar results were not obtained by incorporating 5 mol% of 1‐stearoyl‐2‐linoleoyl‐PC (SLPC). In our model system, free‐radical generation was initiated by extended incubation of the liposomes, by induction by 2,2′‐azobis(2‐amidinopropane)hydrochloride, or by ultraviolet irradiation of H2O2. The rate of consumption of molecular oxygen was studied by monitoring the oxygen concentration in the aqueous phases of the liposomes. The effect of 5 mol% SCLAPC in soy PC was significantly larger than 5 mol% SLPC in soy PC; the response patterns with soy PC and EYPC were similar. Furthermore, 5 mol% SCLAPC in 1‐palmitoyl‐2‐linoleoyl‐PC showed similar oxygen consumption to that observed with 5 mol% SCLAPC in EYPC. On the other hand, 5 mol% SCLAPC in synthetic PC membranes containing saturated or monounsaturated fatty acids showed low oxygen depletion rates. The perturbation of membrane structure and the increase of the relative oxygen diffusion‐concentration products provided a potential mechanism by which CLA incorporated into membrane lipids could affect oxidative stress.
Interaction of curcumin with human serum albumin—A spectroscopic study
Authors: Pulla Reddy A. Ch , Sudharshan E. , Appu Rao A. G. , Lokesh B. R.
Published: November 2006

Curcumin (diferuloyl methane) has a wide range of physiological and pharmacological actions. Curcumin interaction with human serum albumin (HSA) has been followed by fluorescence quenching and circular dichroism (CD) measurements. Based on fluorescence measurements, the equilibrium constant for the interaction is 2.0±0.2×105M−1. Binding of curcumin to HSA induces an extrinsic CD band in the visible region. From the induced CD band measurements, the equilibrium constant has a value of 2.1±0.3×104M−1. Thus, HSA has two kinds of affinity sites for curcumin, one with high affinity and the other with lower affinity. Job's plot indicated a binding stoichiometry of 1∶1 for the high‐affinity site. The equilibrium constant was invariant with temperature in the range of 15 to 45°C, suggesting the role of hydrophobic interactions in the binding of curcumin to HSA. Curcumin does not change the conformation of the HSA molecule. These measurements have implications in the understanding of the curcumin transport under physiological conditions.
Solubilization and stabilization of carotenoids using micelles: Delivery of lycopene to cells in culture
Authors: Xu Xiaoying , Wang Yan , Constantinou Andreas I. , Stacewicz‐Sapuntzakis Maria , Bowen Phyllis E. , van Breemen Richard B.
Published: November 2006

The use of the organic cosolvents tetrahydrofuran and dimethylsulfoxide was found to be unsuitable for prostate tunor cell cultures because of solvent cytotoxicity and the poor solubility and instability of lycopene. For example, the half‐life of lycopene in organic/aqueous solution was found to be less than 2 h. Therefore, a micellar preparation of lycopene was developed for the solubilization and stabilization of lycopene in cell culture media. Neither the micelles themselves nor lycopene solubilized in micelles at concentrations up to 10 μg/mL. in the cell culture media produced cytotoxicity or inhibition of cell proliferation in either LNCaP human prostate cells or Hs888Lu human lung cells. Lycopene solubilized in micelles was stable for at least 96 h under standard cell culture conditions so that a constant lycopene supply could be provided to the cells. During the culture process, lycopene was taken up by LNCaP cells and reached a plateau at approximately 12 h. Micelles provide a convenient, inexpensive, and nontoxic vehicle for dissolving and stabilizing carotenes such as lycopene in tissue culture media and then delivering them to cells growing in culture.
Regulation of mevalonate synthesis in low density lipoprotein receptor knockout mice fed n‐3 or n‐6 polyunsaturated fatty acids
Authors: El‐Sohemy Ahmed , Archer Michael C.
Published: November 2006

3‐Hydroxy‐3‐methylglutaryl (HMG)‐CoA reductase, the rate‐limiting enzyme in cholesterol biosynthesis, catalyzes the formation of mevalonate which is also required for cell proliferation. Changes in HMG‐CoA reductase may mediate the differential effects of n‐3 and n‐6 polyunsaturated fatty acids (PUFA) on experimental mammary tumorigenesis, but the mechanisms by which these fatty acids regulate HMG‐CoA reductase are unclear. To determine whether the low density lipoprotein receptor (LDL‐R) is required for this regulation, groups of female LDL‐R knockout (−/−) and wild‐type (+/+) mice were fed 7% fat diets rich in either n‐3 (menhaden oil) or n‐6 (safflower oil) PUFA for 1 wk. Dietary PUFA and deletion of the LDL‐R had independent effects on HMG‐CoA reductase and serum lipids, and a significant diet‐gene interaction was observed. The effects of PUFA on HMG‐CoA reductase in the mammary gland, but not the liver, were mediated by the LDL‐R. We also observed that differences in HMG‐CoA reductase and serum LDL‐cholesterol, high density lipoprotein cholesterol, and triglycerides between −/− and +/+ mice were dependent on whether the mice were fed n‐3 or n‐6 PUFA. Differences between −/− and +/+ mice were much greater when animals were fed n‐6 PUFA rather than n‐3 PUFA. These results show that the LDL‐R mediates the effects of PUFA on HMG‐CoA reductase in the mammary gland but not the liver. Furthermore, the composition of dietary PUFA profoundly influences the effects of deleting the LDL‐R on HMG‐CoA reductase and serum lipids and suggests that diet may influence the phenotype of other knockout or transgenic animals.
Effects of ψ‐linolenic acid and docosahexaenoic acid in formulae on brain fatty acid composition in artificially reared rats
Authors: Ward G. R. , Huang Y. ‐S. , Xing H. ‐C. , Bobik E. , Wauben I. , Auestad N. , Montalto M. , Wainwright P. E.
Published: November 2006

This study evaluated the effects of dietary supple‐mentation with ψ‐linolenic acid (GLA, 18∶3n−6) and docosahexaenoic acid (DHA, 22∶6n−3) on the fatty acid composition of the neonatal brain in gastrostomized rat pups reared artificially from days 5–18. These pups were fed rat milk substitutes containing fats that provided 10% linoleic acid and 1% α‐linolenic acid (% fatty acids) and, using a 2×3 factorial design, one of two levels of DHA (0.5 and 2.5%), and one of three levels of GLA (0.5, 1.0, and 3.0%). A seventh artificially reared groups served as a reference group and was fed 0.5% DHA and 0.5% arachidonic acid (AA, 20∶4n−6); these levels are within the range of those found in rat milk. The eighth group, the suckled control group, was reared by nursing dams fed a standard American Institute of Nutrition 93M chow. The fatty acid composition of the phosphatidylethanolamine, phosphatidyl‐choline, and phosphatidylserine/phosphatidylinositol membrane fractions of the forebrain on day 18 reflected the dietary composition in that high levels of dietary DHA resulted in increases in DHA but decreases in 22∶4n−6 and 22∶5n−6 in brain. High levels of GLA increased 22∶4n−6 but, in contrast to previous findings with high levels of AA, did not decrease levels of DHA. These results suggest that dietary GLA, during development, differs from high dietary levels of AA in that it does not lead to reductions in brain DHA.
Infant cerebellar gray and white matter fatty acids in relation to age and diet
Authors: Jamieson E. C. , Farquharson J. , Logan R. W. , Howatson A. G. , Patrick W. J. A. , Weaver L. T. , Cockburn F.
Published: November 2006

There is little evidence as to the fatty acid composition of the cerebellum in infancy and it remains uncertain whether milk diet can influence its composition. We therefore examined cerebellar gray and white matter of infants less than 6 mon old who had died unexpectedly. The fatty acid content of 33 gray and 21 white matter specimens from infants born at term and 6 gray and 5 white matter specimens from pretern infants was assessed by gas chromatographic/mass spectrometric analysis. Infants were grouped according to whether they had received human or manufactured formula milk. Whereas cerebellar cortex docosahexaenoic acid (DHA, 22∶6n−3) concentrations were significantly lower (P<0.01) in the formula‐fed than breast‐fed infants, no differences existed between the term (n=10) and preterm (n=5) Scientific Milk Adaptation (SMA) formula‐fed infants. Cerebellar white matter DHA concentrations were similarly lower (P<0.01) in the SMA formula‐fed infants (n=8) than in an age‐matched breast‐fed group. Low concentrations of cerebellar white matter lignoceric (24∶0) and nervonic acid (24∶1n−9) in two 7‐wk‐old preterm infants appeared to correlated with postgestational rather than chronological age. Dietary long‐chain polyunsaturated fatty acids particularly DHA, are probably essential for normal development of the infant cerebellum.
Arachidonic, eicosapentaenoic, and biosynthetically related fatty acids in the seed lipids from a primitive gymnosperm, Agathis robusta
Authors: Wolff Robert L. , Christie William W. , Pédrono Frédérique , Marpeau Anne M.
Published: November 2006

The fatty acid composition of the seeds from Agathis robusta, an Australian gymnosperm (Araucariaceae), was determined by a combination of chromatographic and spectrometric techniques. These enabled the identification of small amounts of arachidonic (5,8,11,14–20∶4) and eicosapentaenoic (5,8,11,14,17–20∶5) acid for the first time in the seed oil of a higher plant. They were apparently derived from γ‐linolenic (6,9,12–18∶3) and stearidonic (6,9,12,15–18∶4) acids, which were also present, via chain elongation and desaturation, together with other expected biosynthetic intermediates [bis‐homo‐γ‐linolenic (8,11,14–20∶3) and bishomo‐stearidonic (8,11,14,17–20∶4) acids]. Also present were a number of C20 fatty acids, known to occur in most gymnosperm families, i.e., 5,11–20∶2, 11,14–20∶2 (bishomo‐linoleic), 5,11,14–20∶3 (sciadonic), 11,14,17–20∶3 (bishomo‐α‐linolenic), and 5,11,14,17–20∶4 (juniperonic) acids. In contrast to most other gymnosperm seed lipids analyzed so far, A. robusta seed lipids did not contain C18 Δ5‐desaturated acids [i.e., 5,9–18∶2 (taxoleic), 5,9,12–18∶3 (pinolenic), or 5,9,12,15–18∶4 (coniferonic)]. These structures support the simultaneous existence of Δ6‐ and Δ5‐desaturase activities in A. robusta seeds. The Δ6‐ethylenic bond is apparently introduced into C18 polyunsaturated acids, whereas the Δ5‐ethylenic bond is introduced into C20 polyunsaturated acids. A general metabolic pathway for the biosynthesis of unsaturated fatty acids in gymnosperm seeds is proposed. When compared to Bryophytes, Pteridophytes (known to contain arachidonic and eicosapentaenoic acids), and species from other gymnosperm families (without such acids), A. robusta appears as an “intermediate,” with the C18 Δ6‐desaturase/C18→C20 elongase/C20 Δ5‐desaturase system in common with the former subphyla, and the unsaturated C18→C20 elongase/C20 Δ5‐desaturase system specific to gymnosperms. The following hypothetical evolutionary sequence for the C18 Δ6/Δ5‐desaturase class in gymnosperm seeds is suggested: Δ6 (initial)→Δ6/Δ5 (intermediate)→Δ5 (final).
Lipids of the pawpaw fruit: Asimina triloba
Authors: Wood Randal , Peterson Scott
Published: November 2006

The fatty acid composition and structure of pawpaw fruit (Asimina triloba) triglycerides were examined and found to contain fatty acids ranging from C6 to C20. Octanoate represented 20% of the fatty acids while other medium‐chain fatty acids were present in low amounts. Analysis of the intact triglycerides by high‐temperature gas‐liquid chromatography gave an unusual three‐cycle carbon number distribution. Analysis of triglyceride fractions separated according to degree of unsaturation suggested that one octanoate was paired with diglyceride species containing long‐chain fatty acids. Determination of the double‐bond positions of monoene fatty acids revealed cis Δ9 and cis Δ11 hexadecenoate and cis Δ9, cis Δ11, and cis Δ13 octadecenoate isomers were present in significant quantities. Octanoate and positional monoene fatty acid isomers were found only in the fruit lipids and not in the seed lipids. Phenacyl esters of fatty acids were found to be useful derivatives for structure determination using multiple types of analyses.
Stability of cyclopropane and conjugated linoleic acids during fatty acid quantification in lactic acid bacteria
Authors: Dionisi Fabiola , Golay Pierre‐Alain , Elli Marina , Fay Lauren B.
Published: November 2006

Seven methods commonly used for fatty acid analysis of microgrganisms and foods were compared to establish the best for the analysis of lyophilized lactic acid bacteria. One of these methods involves fat extraction followed by methylation of fatty acids, while the other methods use a direct methylation of the samples, under different operating conditions (e.g., reaction temperature and time, reagents, and pH). Fatty acid methyl esters were identified by gas chromatography‐mass spectrometry and quantified by on‐column capillary gas chromatography. Two reliable methods for the analysis of fatty acids in bacteria were selected and further improved. They guarantee high recovery of classes of fragile fatty acids, such as cyclopropane and conjugated acids, and a high degree of methylation for all types of fatty acid esters. These two direct methylation methods have already been successfully applied to the analysis of fatty acids in foods. They represent a rapid and highly reliable alternative to classical time‐and solvent‐consuming methods and they give the fatty acid profile and the amount of each fatty acid. Using these methods, conjugated linoleic acids were identified and quantified in lactic acid bacteria.
Synthesis of trans‐4,5‐epoxy‐(E)‐2‐decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization
Authors: Lin Jianming , Fay Laurent B. , Welti Dieter H. , Blank Imre
Published: November 2006

The volatile compound trans‐4,5‐epoxy‐(E)‐2‐decenal (1) was synthesized in two steps with good overall yields. The newly developed method is based on trans‐epoxidation of (F)‐2‐octenal with alkaline hydrogen peroxide followed by a Wittig‐type chain elongation with the ylide formylmethylene triphenylphosphorane. For the synthesis of [4,5‐2H2]‐trans‐4,5‐epoxy‐(E)‐2‐decenal (d‐1), [2,3‐2H2]‐(E)‐2‐octenal was prepared by reduction of 2‐octyn‐1‐ol with lithium aluminum deuteride and subsequent oxidation of [2,3‐2H2]‐(E)‐2‐octen‐1‐ol with manganese oxide. Compound d‐1 was used as internal standard for the quantification of 1 by isotope dilution assay. Among various mass spectrometry (MS) ionization techniques tested, negative chemical ionization with ammonia as reagent gas gave best results with respect to both sensitivity and selectivity. The detection limit was found to be at about 1 pg of the analyte introduced into the gas chromatography‐MS system.
Acyclic and incompletely cyclized triterpene alcohols in the seed oils of theaceae and Gramineae
Authors: Akihisa Toshihiro , Koike Kazuo , Kimura Yumiko , Sashida Norio , Matsumoto Taiji , Ukiya Motohiko , Nikaido Tamotsu
Published: November 2006

The triterpene alcohol constituents of the non‐saponifiable lipids of two Theaceae seed oils, sasanqua and camellia oils, and two Gramineae seed oils, wheat germ and rice bran oils, were investigated. This led to the isolation and characterization of one acyclic and eight incompletely cyclized triterpene alcohols. They are camelliol A, camelliol B, camelliol C, achilleol A, helianol, isohelianol, sasanquol, graminol A [(13R, 14R)‐3,4‐seco‐25(10→9)abeo‐8α,9β,10α‐podioda‐4,17,21‐trien‐3‐ol], and (2Z,6Z,10Z,14E,18E)‐farnesylfarnesol. Two other compounds isolated were characterized as (2Z,6Z,10E,14E)‐geranylfarnesol, a sesterterpene alcohol, and phytol, a diterpene alcohol. Graminol A and (2Z,6Z,10E,14E)‐geranylfarnesol are considered to be new natural products.
Wax ester‐synthesizing activity of lipases
Authors: Tsujita Takahiro , Sumiyoshi Maho , Okuda Hiromichi
Published: November 2006

The synthesis/hydrolysis of wax esters was studied in an aqueous solution using purified rat pancreatic lipase, porcine pancreatic carboxylester lipase, and Pseudomonas fluorescens lipase. The equilibrium between wax ester synthesis and hydrolysis favored ester formation at neutral pH. The synthesizing activities were measured using free fatty acid or triacylglycerol as the acyl donor and an equimolar amount of long‐chain alcohol as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with these lipases, was ester was synthesized, in a dose‐ and time‐dependent manner, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was about 0.9/0.1. These lipases catalyzed the hydrolysis of palmityl oleate emulsified with gum arabic, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was also about 0.9/0.1. The apparent equilibrium ratio of wax ester/free fatty acid catalyzed by lipase depended on incubation pH and fatty alcohol chain length. When equimolar amounts of trioleoylglycerol and fatty acyl alcohol were incubated with pancreatic lipase, carboxylester lipase, or P. fluorescens lipase, wax esters were synthesized dose‐dependently. These results suggest that lipases can catalyze the synthesis of wax esters from free fatty acids or through degradation of triacylglycerol in an aqueous medium.
Metabolism of n−3 and n−6 fatty acids in Atlantic salmon liver: Stimulation by essential fatty acid deficiency
Authors: Ruyter B. , Thomassen M. S.
Published: November 2006

Oxidation, esterification, desaturation, and elongation of [1‐14C]18∶2n−6 and [1‐14C]18∶3n−3 were studied using hepatocytes from Atlantic salmon (Salmo salar I.) maintained on diets deficient in n−3 and n−6 polyunsaturated fatty acids (PUFA) or supplemented with n−3 PUFA. For both dietary groups, radioactivity from 18∶3n−3 was incoporated into lipid fractions two to three times faster than from 18∶2n−6, and essential fatty acids (FFA) deficiency doubled the incorporation. Oxidation to CO2 was very low and was independent of substrate or diet, whereas oxidation to acid‐soluble products was stimulated by EFA deficiency. Products from 18∶2n−6 were mainly 18∶3n−6, 20∶3n−6, and 20∶4n−6, with minor amounts of 20∶2n−6 and 22∶5n−6. Products from 18∶3n−3 were mainly 18∶4n−3, 20∶5n−3, and 22∶6n−3, with small amounts of 20∶3n−3. The percentage of 22∶6n−3 in the polar lipid fraction of EFA‐deficient hepatocytes was fourfold higher than in n−3 PUFA‐supplemented cells. This correlated well with our other results obtained after abdominal injection of [1‐14C]18∶3n−3 and [1‐14C]18∶2n−6. In hepatocytes incubated with [4,5‐3H]‐22∶6n−3, 20∶5n−3 was the main product. This retrocon‐version was increased by EFA deficiency, as was peroxisomal β‐oxidation activity. This study shows that 18∶2n−6 and 18∶3n−3 can be elongated and desaturated in Atlantic salmon liver, and that this conversion and the activity of retroconversion of very long chain PUFA is markedly enhanced by FFA deficiency.
Thioglycolate‐elicited rat macrophages exhibit alterations in incroporation and oxidation of fatty acids
Authors: Peres C. M. , Procopio J. , Costa M. , Curi R.
Published: November 2006

Incorporation and oxidation of fatty acids (FA) were investigated in resident and thioglycolate‐clicited (TG‐elicited) rat macrophages (Mϕ). Both cell types presented a time‐dependent incorporation of [14C]‐labeled palmitic acid (PA), oleic acid (OA), linoleic acid (LA), and arachidonic acid (AA) up to 6h. The total amount of [14C]‐FA incorporated by resident Mϕ after 6 h was: AA>PA=LA>OA. TG‐elicited cells presented a 50% reduction in the incorporation of LA, PA, and AA, whereas that of OA remained unchanged as compared to resident Mϕ. The FA were oxidized by resident Mϕ as follows: LA>OA>PA>AA. TG elicitation promoted a reduction of 42% in LA oxidation and a marked increase in AA oxidation (280%). The increased oxidation of AA in TG‐elicited cells may account for the lower production of prostaglandins in Mϕ under these conditions. The full significance of these findings for Mϕ function, however, remains to be examined.
Fatty acid Δ9‐Desaturation in the Triatoma infestans fat body: Response to food and trehalose administrationsin the Triatoma infestans fat body: Response to food and trehalose administrations
Authors: González María S. , Brenner Rodolfo R.
Published: November 2006

The effects of food intake and carbohydrate administration on fatty acid Δ9‐desaturation were investigated in isolated microsomes from Triatoma infestans fat body. Fifth instar nymphs, which were solely blood‐fed just after the molt and then fasted, were used as controls and for determination of optimal assay conditions. Both [1‐14C]palmitic and [1‐14C]stearic acids in a medium containing ATP, CoA, MgCl2, NADH, NaF, and O2 were tested. For the control group, optimal conditions were a pH of 6.8–7.2, an incubation temperature of 29°C, and an incubation time of 10 min. Δ9‐desaturation depended on the presence of reduced pyridine dinucleotides; NADH and NADPH were equally efficient. Stearic acid showed a higher apparent Vmax than palmitic acid, but the apparent Km were very similar. When fifth instar nymphs were blood‐fed weekly, a marked increase of Δ9‐desaturation was observed for both acids. Higher desaturation activity was also induced by injection of the carbohydrate trehalose into the hemolymph of fasted nymphs. These results indicate that insect Δ9‐desaturation, like the mammalian counterpart, is sensitive to dietary changes and carbohydrate administration. *** DIRECT SUPPORT *** A01K6035 00008
Lipid composition of eggs of an oviparous lizard (Bassiana duperreyi)
Authors: Speake Brian K. , Thompson Michael B. , McCartney Ruth J.
Published: November 2006

Lipid analysis was performed on freshly ovulated eggs (n=5) of the oviparous lizard Bassiana duperreyi. The fresh weight of the whole egg contents was 132.0±4.3 mg (mean+SF) of which lipid constituted 21.9+1.1% (w/w). Iriacylglycerol formed an exceptionally high proportion (85.4+ 0.5%, w/w) of the total lipid, whereas phospholipid, free cholesterol, cholesteryl ester, and free fatty acid, respectively, contributed 11.2±0.3, 1.4±0.1,1.3±0.1, and 0.6±0.1% of the total lipid mass. Linoleic and α‐linolenic acids were the major polyunsaturates of the triacylglycerol fraction, respectively, forming 16.3±0.1 and 8.3±0.1% (w/w) of the fatty acids. Linoleic acid was the major fatty acid (29.0±0.1%) of the total phospholipid, which also contained substantial amounts of arachidonic (6.4±0.1%) and eicosapentaenoc (3.0±0.1%) acids, but a relatively low proportion (1.6±0.1%) of docosahexaenoic acid. Phosphatidylcholine formed the major phospholipid class (73.8±2.3% w/w of total phospholipid) and was enriched in linodeic acid, whereas phosphatidylethanolamine, which formed 20.4±1.9% (w/w) of total phospholipid, contained higher proportions of arachidonic and docosahexaenoic acids.
Competition between Li+ and Mg2+ for red blood cell membrane phospholipids: A 31P, 7Li, and 6Li nuclear magnetic resonance study
Authors: Srinivasan Chandra , Minadeo Nicole , Geraldes Carlos F. G. C. , de Freitas Duarte Mota
Published: November 2006

The mode of action of the lithium ion (Li+) in the treatment of manic depression or bipolar illness is still under investigation, although this inorganic drug has been in clinical use for 50 yr. Several research reports have provided evidence for Li+/Mg2+ competition in biomolecules. We carried out this study to characterize the interactions of Li+ and Mg2+ with red blood cell (RBC) membrane components to see whether Li+/Mg2+ competition occurs. 31P nuclear magnetic resonance chemical shift measurements of the phospholipids extracted from the RBC membranes indicated that the anionic phospholipids, phosphatidylserine and phosphatidylinositol, bind Li+ and Mg2+ most strongly. From 6Li relaxation measurements, the Li+ binding constant to the phospholipid extract was found to be 45±5M−1. Thus, these studies showed that the phospholipids play a major role in metal ion binding. 7Li spin‐lattice relaxation measurements conducted on unsealed and cytoskeleton‐depleted RBC membrane in the presence of magnesium indicated that the removal of the cytoskeleton increases lithium binding to the more exposed anionic phospholipids (357±24 M−1) when compared to lithium binding in the unsealed RBC membrane (221±21 M−1). Therefore, it can be seen that the cytoskeleton does not play a major role in Li+ binding or in Li+/Mg2+ competition.
Separation and determination of glycolipids from edible plant sources by high‐performance liquid chromatography and evaporative light‐scattering detection
Authors: Sugawara Tatsuya , Miyazawa Teruo
Published: November 2006

Glycolipids from edible plant sources were accurately quantified by silica‐based, normal‐phase high‐performance liquid chromatography using an evaporative light‐scattering detector. Five major glycolipid classes (acylated steryl glucoside, steryl glucoside, ceramide monohexoside, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol) were separated and determined with a binary gradient system consisting of chloroform and methanol/water (95∶5, vol/vol) without any interference from other lipid classes and pigments. The described method was applied to 48 edible plants available in Japan including cereals, legumes, vegetables, and fruits. Examined plant species contained glycolipids in wide concentration ranges, such as 5–645 mg/100 g tissue.
Effect of the nonenzymatic glycosylation of high density lipoprotein‐3 on the cholesterol ester transfer protein activity
Authors: Lemkadem B. , Loiseau D. , Larcher G. , Malthiery Y. , Foussard F.
Published: November 2006

This study examines the relationship between high density lipoprotein‐3 (HDL‐3) glycation and cholesteryl ester transfer mediated by cholesteryl ester transfer protein (CETP). HDL‐3 were glycated with various glucose concentrations (0–200 mM) for 3 d at 37°C with sodium cyanoborohydride as reducing agent and antioxidants. About 47% of the lysine residues were glycated in the presence of 200 mM glucose, resulting in an increase in the cholesterol ester (CE) transfer of about 30%. Apparent kinetic parameters [expressed as maximal transfer (appTmax) and CE concentration at half of Tmax (appKH)] of CETP activity with glycated HDL‐3 showed conflicting and paradoxical data: an increase in CETP activity associated with a decrease of CETP affinity. These alterations were not due to a change in HDL‐3 lipid and protein composition nor to a peroxidative process but were associated with an increase in HDL‐3 electronegativity and a decrease of HDL‐3 fluidity. This study suggests that glycation modifies the apolipoprotein's conformation and solvation which are major determinants of interfacial properties of HDL‐3. These modifications in turn affect CETP reactivity.
Effects of eicosapentaenoic acid and docosahexaenoic acid on plasma membrane fluidity of aortic endothelial cells
Authors: Hashimoto Michio , Hossain Md. Shahdat , Yamasaki Hiroshi , Yazawa Kazunaga , Masumura Sumio
Published: November 2006

We investigated the relative effects of n−3 eicosapentaenoic acid (EPA, 20∶5n−3) and docosahexaenoic acid (DHA, 22∶6n−3) on the plasma membrane fluidity of endothelial cells (EC) cultured from the thoracic aorta by determining fluorescence polarization of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) and its cationic derivative trimethylamino‐DPH (TMA‐DPH). Fluidity assessed by TMA‐DPH demonstrated no significant differences in plasma membranes of vehicle (dimethyl sulfoxide; DMSO)‐, EPA‐, and DHA‐treated EC. Plasma membrane fluidity assessed by DPH polarization, however, was significantly higher in the order of DHA>EPA>DMSO. Total cholesterol content decreased significantly by 28.4 and 15.9% in the plasma membranes of DHA‐ and EPA‐treated cells, respectively. Total phospholipid content remained unaltered in the plasma membranes of the three groups of cells; however, the molar ratio of total cholesterol to phospholipid decreased significantly only in the membranes of DHA‐treated EC. The unsaturation index in the plasma membranes of EPA‐ and DHA‐treated cells increased by 35.7 and 64.3%, respectively, compared with that in the plasma membranes of control cells. The activities of catalase and glutathione peroxidase in the whole‐cell homogenates, and levels of lipid peroxides in either the whole‐cell homogenates or in plasma membrane fractions were not altered in EPA‐ or DHA‐treated EC. These results indicate that the influence of DHA is greater than that of EPA in increasing plasma membrane fluidity of vascular EC. We speculate that the greater effect of DHA compared to EPA is due to its greater ability to decrease membrane cholesterol content or the cholesterol/phospholipid molar ratio, or both, and also to its greater ability in elevating the unsaturation index in the plasma membranes of EC.
Atorvastatin and simvastatin have distinct effects on hydroxy methylglutaryl‐CoA reductase activity and mRNA abundance in the guinea pig
Authors: Conde Karin , Roy Suheeta , Freake Hedley C. , Newton Roger S. , Fernandez Maria Luz
Published: November 2006

The effects of atorvastatin and simvastatin on hydroxy methylglutary (HMG)‐CoA reductase activity and mRNA abundance were studied in guinea pigs randomized to three groups: untreated animals and those treated with 20 mg/kg of atorvastatin or simvastatin. Guinea pigs were fasted for 0, 6, 12, or 18 h in an attempt to remove the drug from their systems. Reductase activity and mRNA levels were analyzed after each time point. Reductase inhibitor treatment resulted in 50–60% lower cholesterol concentrations compared to untreated guinea pigs (P<0.0001), while plasma triacylglycerol (TAG) concentrations did not differ among groups. Plasma cholesterol and TAG were 50–70% lower after 18 h fasting in the three groups (P<0.001). In the nonfasting state, simvastatin and atorvastatin treatment did not affect HMG‐CoA reductase activity compared with untreated animals. However, after 6 h of fasting, simvastatin‐treated guinea pigs had higher HMG‐CoA reductase activity than untreated animals (P<0.01), suggesting that the drug had been removed from the enzyme. In contrast, atorvastatin‐treated guinea pigs maintained low enzyme activity even after 18 h of fasting. Further, HMG‐CoA reductase mRNA abundance was increased by sevenfold after atorvastatin treatment and by twofold after simvastatin treatment (P<0.01). These results suggest that sinvastatin and atorvastatin have different half‐lives, which may affect HMG‐CoA reductase mRNA levels. The increase in reductase activity by simvastatin during fasting could be related to an effect of this statin in stabilizing the enzyme. In contrast, atorvastatin, possibly due to its longer half‐life, prolonged inhibition of HMG‐CoA reductase activity and resulted in a greater increase in mRNA synthesis.
Nondestructive NMR determination of oil composition in transformed canola seeds
Authors: Hutton William C. , Garbow Joel R. , Hayes Thomas R.
Published: November 2006

Magic‐angle spinning (MAS) 13C nuclear magnetic resonance (NMR) spectroscopy is a convenient method for nondestructive, quantitative characterization of seed oil composition. We describe results for intact hybrid and transformed canola seeds. The MAS 13C NMR technique complements and agrees with gas chromatography results. The spectral resolution approaches that of neat, liquid oils. MAS 13C NMR data allow quantitative analysis of major oil components, including saturates and oleic, linoleic, and linolenic acyl chains. 13C NMR directly and quantitatively elucidates, triglyceride regiochemistry and acyl chain cis‐trans isomers that cannot be quickly detected by other methods. MAS 13C NMR can serve as the primary method for development of near‐infrared seed oil calibrations. These NMR methods are nondestructive and attractive for plant‐breeding programs or other studies (e.g., functional genomics) where loss of seed viability is inconvenient.
A rapid and quantitative method for total fatty acid analysis of fungi and other biological samples
Authors: Sönnichsen M. , Müller B. W.
Published: November 2006

A quantitative method for the one‐step esterification and determination of absolute amounts of polyunsaturated fatty acids in biotechnologically produced fungal mycelia is proposed. A system of two internal standards was used to quantify the total fatty acid content of the samples by gas chromatography. The degree of methylation of the analyzed fatty acids was calculated using the internal standards, and subsequently this quotient was used to validate the derivatization and extraction reactions. By utilizing this degree of methylation, the corrected amounts of the various fatty acids in the sample can be calculated.
Sex‐and age‐related differences in ceramide dihexosides of primary human brain tumors
Authors: Yates Allan J. , Franklin Teresa K. , Scheithauer Berndt W. , Burger Peter C. , Pearl Dennis K.
Published: November 2006

Neutral glycolipids (NGL) are promising diagnostic markers of human gliomas, but differences in NGL with age and sex have not been examined. Previous work demonstrated that ceramide dihexosides (CDH) levels in mouse kidney are age‐ and sex‐dependent, probably due to levels of sex hormones. We quantitated CDH in 181 human gliomas and found significant differences with sex and age, particularly menopause and male puberty. This emphasizes the importance of assessing results of studies on glycolipids in disease states with respect to age and sex in order to avoid erroneous conclusions concerning the relationship of glycolipid composition with diagnosis and pathogenesis.
Dietary α‐linolenate suppresses endotoxin‐induced platelet‐activating factor production in rat kidney
Authors: Oh‐hashi Kentaro , Takahashi Tetsuya , Tanabe Akiko , Watanabe Shiro , Okuyama Harumi
Published: November 2006

In comparison with dietary high‐linoleate safflower oil, high α‐linolenate perilla oil decreased alkylacyl‐and alkenylacyl‐glycerophosphocholine (GPC) content in rat kidney by roughly 30 and 25%, respectively. The fatty acid composition was also modified by high α‐linolenate oil; arachidonic acid (AA) level in alkylacyl‐GPC, a platelet‐activating factor (PAF) precursor, decreased by 30% along with concomitant increases in the n‐3 fatty acid levels. PAF contents under resting conditions were similarly low in the two dietary groups. Fifteen minutes after endotoxin administration, PAF and lyso‐PAF contents increased significantly, and the PAF content in the high α‐linolenate group was 60% lower than in the high linoleate group; the lyso‐PAF contents also tended to be lower. Lyso‐PAF acetyltransferase and CoA‐independent transacylase activities in kidney microsomes increased significantly after endotoxin administration, while PAF acetylhydrolase activity in the cytosol was relatively unchanged. The lyso‐PAF acetyltransferase and PAF acetylhydrolase activities did not differ between the two dietary groups, but the CoA‐independent, transacylase activity was roughly 30% lower in the high α‐linolenate group. In agreement with in vitro study, our present study demonstrates that dietary high α‐linolenate suppresses PAF production in rat kidney during systemic endotoxemia, and which is mainly due to the decrease in alkylacyl‐GPC content, altered fatty acid compositions of the precursor lipids and lower CoA‐independent transacylase activity.
Effects of Pinus pinaster and Pinus koraiensis seed oil supplementation on lipoprotein metabolism in the rat
Authors: Asset Gaëlle , Staels Bart , Wolff Robert L. , Baugé Eric , Madj Zouher , Fruchart Jean‐Charles , Dallongeville Jean
Published: November 2006

The aim of the present study was to assess the effect of vegetal oils obtained from Pinus pinaster and P. koraiensis seeds on plasma lipoprotein levels and apolipoprotein (apo) gene expression in rats. These oils contain two particular fatty acids of the Δ5‐unsaturated polymethylene‐interrupted fatty acid (Δ5‐UPIFA) family: all‐cis‐5,9,12‐18:3 (pinolenic) and/or all‐cis‐5,11,14‐20:3 (sciadonic) acids. Rats were fed for 28 d a diet containing 5% (w/w) oil supplement. Two control diets were prepared to match the fatty acid composition of P. pinaster or P. koraiensis oils with the exception of Δ5‐UPIFA, which were replaced by oleic acid. Pinus pinaster seed oil decreased serum triglycerides by 30% (P<0.02), very low density lipoprotein (VLDL)‐triglycerides by 40% (P<0.01), and VLDL‐cholesterol by 33% (P<0.03). Pinus koraiensis seed oil decreased serum triglycerides by 16% [not statistically significant (ns)] and VLDL‐triglycerides by 21% (ns). Gel permeation chromatography and nondenaturating polyacrylamide gel electrophoresis showed a tendency of high density lipoprotein to shift toward larger particles in pine seed oil‐supplemented rats. Finally, P. pinaster seed oil treatment was associated with a small decrease of liver apoC‐III (P<0.02) but not in apoE, apoA‐I, or apoA‐II mRNA levels. The levels of circulating apo were not affected by pine seed oil supplementation. In conclusion, P. pinaster seed oil has a triglyceride‐lowering effect in rats, an effect that is due to a reduction in circulating VLDL.
Differences in the sterol composition of dominant antarctic zooplankton
Authors: Mühlebach Anneke , Albers Carola , Kattner Gerhard
Published: November 2006

The composition of free sterols was determined in Antarctic zooplankton species with various feeding behaviors. In the Southern Ocean, the dominant calanoid copepods Calanoides acutus, Calanus propinquus, Metridia gerlachei, and Euchaeta antarctica were investigated during different seasons and compared with the euphausiids Euphausia superba, E. crystallorophias, and Thysanoessa macrura. In addition, the Arctic copepods Calanus hyperboreus, C. glacialis, and C. finmarchicus were studied for comparison. Analyses were performed using gas chromatography and mass spectrometry. The zooplankton species exhibited a simple sterol content of up to six sterols. In the copepods, cholest‐5‐en‐3β‐ol (22.1 to 60.5%, range of sample means), cholesta‐5,24‐dien‐3β‐ol (22.3 to 45.2%), and cholesta‐5,22E‐dien‐3β‐ol (4.3 to 33.4%) contributed most, while in euphausiids the sterol composition was less complex with cholest‐5‐en‐3β‐ol always accounting for more than 75% of the total. Although sterols are membrane constituents and are expected not to vary considerably, differences in the abundance of sterols were observed between the species and the seasons. In herbivorous copepods, cholesta‐5,24‐dien‐3β‐ol increased by a factor of 1.5 to about 45% during the main feeding period in summer; this sterol is a metabolic precursor of cholest‐5‐en‐3β‐ol in the process of the dealkylation of dietary C‐24 alkylated phytosterols. Cholest‐5‐en‐3β‐ol decreased by the same proportion. Omnivorous and carnivorous copepods showed average levels of cholesta‐5,24‐dien‐3β‐ol below 25%. These changes in sterol composition between copepod species seem to reflect their different feeding modes.
Mitochondrial membrane composition of two arctic marine bivalve mollusks, Serripes groenlandicus and Mya truncata
Authors: Gillis Todd E. , Ballantyne James S.
Published: November 2006

The phospholipid and fatty acid composition of gill mitochondria membranes from two Arctic marine bivalve mollusks, Mya truncata and Serripes groenlandicus, were examined. These animals were collected from the Arctic Ocean, where waters remain below 0°C throughout the year. In both species, the primary membrane phospholipids were phosphatidylcholine, and phosphatidylethanolamine. Although a low ratio of bilayer‐stabilizing phospholipids to bilayer‐destabilizing phospholipids is frequently associated with cold acclimation in temperate species, this ratio is very different between the two species. The monounsaturated fatty acid 20∶1 was abundant in the membranes of both Arctic species equaling 13.0% of the fatty acid composition in S. groenlandicus, and 17.7% in M. truncata. Polyunsaturated fatty acids were relatively low in the Arctic species, equaling 35.9% of total membrane fatty acids compared to that of temperate zone mollusks. It is suggested that monoenes are common in the tissues of Arctic species since they play a role in maintaining membrane function at subzero temperatures.
Influences of subzero thermal acclimation on mitochondrial membrane composition of temperate zone marine bivalve mollusks
Authors: Gillis Todd E. , Ballantyne James S.
Published: November 2006

The phospholipid and phospholipid fatty acid composition of gill mitochondrial membranes from two temperate zone marine bivalve mollusks, the quahog, Mercenaria mercenaria, and the American oyster, Crassostrea virginica, were examined after acclimation to 12 and −1°C. Cardiolipin (CL) was the only phospholipid with proportions altered upon acclimation to −1°C, increasing 188% in the mitochondrial membranes of M. mercenaria. Although the ratio of bilayer stabilizing to destabilizing lipids is frequently associated with cold acclimation in ectothermic species, no change was found in this ratio in either of the species. Polyunsaturated fatty acids (PUFA) were found only to increase in C. virginica with cold acclimation, with total n‐3 PUFA increasing in the phospholipid phosphatidylethanolamine, total n‐6 PUFA increasing in CL, and total PUFA increasing in phosphatidylinositol. Monounsaturated fatty acids, not PUFA, were found to have increased in M. mercenaria, with 18:1n−9 increasing by 150% in CL, and 20∶1 increasing in both CL and phosphatidylcholine, by 146 and 192%, respectively. These manipulations of membrane phospholipid and fatty acid composition may represent an attempt by these species to help maintain membrane function at low temperatures.
Why There Are No Tropes
Authors: Levinson Jerrold
Published: November 2006

This paper effectively inverts the argument of an earlier paper of mine, “The Particularisation of Attributes”, to argue that there are no necessarily particularised and unshareable attributes of the sort that contemporary metaphysics calls tropes. In that earlier paper I distinguished two kinds of attributes, namely, properties and qualities, and argued that if there were tropes they could only be particularised qualities, i.e. particularisations of, say, redness, rather than particularisations of, say, being red. While continuing to hold that there cannot be particularised properties—that the very notion is oxymoronic—I now hold, further, that the supposition of qualities (that is, abstract stuffs) in addition to properties (that is, conditions or ways of being) is both ontologically extravagant and conceptually outlandish. Hence there are no qualities, and thus no tropes either.