bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lysophosphatidylcholine acyltransferase activity in Saccharomyces cerevisiae: Regulation by a high‐affinity Zn2+ binding site
Authors: Richard Martin G. , McMaster Christopher R. 
Published: November 2006

AbstractSaccharomyces cerevisiae cells were demonstrated to contain lysophosphatidylcholine (lysoPtdCho) acyltransferase (E.C. 2.3.1.23) activity. The enzyme displayed Km(app) of 69 μM for lysoPtdCho and 152 μM for oleoyl CoA. Enzyme activity was not affected by the addition of 1 mM Mg2+, Mn2+, Ca2−, or 200 mM EDTA. However, Zn2+ inhibited lysoPtdCho acyltransferase activity to 33% control values at 0.1 mM and to 7% at 1.0 mM Zn2+. To further explore the possibility that lysoPtdCho acyltransferase may contain a high‐affinity Zn2+ binding site, we tested the strong Zn2+ chelator o‐phenanthroline for its ability to inhibit enzyme activity. LysoptdCho acyltransferase activity was inhibited to 18 and 27%, respectively, those of control values in the presence of 2 and 1 mM o‐phenanthroline, implying that a high‐affinity Zn2+ binding site exists in lysoPtdCho acyltransferase or in an accessory protein that is essential for protein stability and/or activity. Saccharomyces cerevisiae lysoPtdCho acyltransferase activity displayed a broad lysoPtdCho fatty acyl chain substrate specificity utilizing lysoPtdCho molecules ranging in length from C10−C20 (the entire range tested). In addition, the enzyme was capable of using the ether‐linked analog of lysoPtdCho, 1‐O‐alkyl‐2‐hydroxy‐sn‐3‐glycerophosphocholine, as a substrate. The ability of S. cerevisiae to incorporate radiolabeled 1‐O‐alkyl‐2‐hydroxy‐sn‐3‐glycerophosphocholine into phosphatidylcholine in vitro was exploited to demonstrate a direct precursor‐product relationship between lysoPtdCho molecules and their incorportation into phosphatidylcholine in vivo. Identical labeling results were obtained in S. cerevisiae cells disrupted for their major transacylase activity, PLB1, demonstrating that the incorporation of lysolipid was via acyltransferase, and not transacylase, activity.
Dietary effects of conjugated octadecatrienoic fatty acid (9 cis, 11 trans, 13 trans) levels on blood lipids and nonenzymatic in vitro lipid peroxidation in rats
Authors: Dhar P. , Ghosh S. , Bhattacharyya D. K. 
Published: November 2006

AbstractThe present study examined the antioxidant activity of conjugated octadecatrienoic fatty acid (9 cis, 11 trans, 13 trans‐18∶3), α‐eleostearic acid, of karela seed (Momordica charantia), fed to rats for 4 wk. The growth pattern of rats and the effect on plasma cholesterol and high density lipoprotein (HDL) cholesterol and peroxidation of plasma lipid, lipoprotein, eryhrocyte membrane, and liver lipid were measured. Rats were raised on diets containing sunflower oil mixed with three different levels of conjugated trienoic fatty acid (9c,11t,13t‐18∶3) 0.5,2, and 10% by weight; the control group was raised with sunflower oil as dietary oil as the source of linoleic acid (9c,12c‐18∶2). The growth pattern of the three experimental groups of rats showed no significant difference compared to the control group of rats, but the group with 10% 9c,11t,13t‐18∶3 had slightly higher body weight than the control group of rats. Concentrations of total cholesterol, HDL‐cholesterol, and non‐HDL‐cholesterol in plasma were similar in all four groups. Plasma lipid peroxidation was significantly lower in the case of 0.5% 9c,11t,13t‐18∶3 group than the control group and the 2 and 10% 9c,11t,13t‐18∶3 dietary groups as well. Lipoprotein oxidation susceptibility test with 0.5,2 and 10% 9c,11t,13t‐18∶3 dietary groups was significantly less susceptible to lipoprotein peroxidation when compared with sunflower oil dietary group, and the dietary group with 0.5% 9c,11t,13t‐18∶3 showed least susceptibility. There was significant lowering in erythrocyte ghost membrane lipid peroxidation in the 0.5,2, and 10% 9c,11t,13t‐18∶3 dietary groups compared to the sunflower oil groups. Nonenzymatic liver tissue lipid peroxidation was significantly lower in the group of rats raised on 0.5% 9c,11t,13t‐18∶3, but the groups on 2 and 10% 9c,11t,13t‐18∶3 acid did not show any significant difference compared with the control group of rats.
Effects of dietary polyunsaturated fatty acids on neuronal function
Authors: Fernstrom John D. 
Published: November 2006

AbstractDiets deficient in linoleic acid (18∶2n−6), or that have unusual ratios of linoleic acid to α‐linolenic acid (18∶3n−3) induce changes in the polyunsaturated fatty acid (PUFA) composition of neuronal and glial membranes. Such changes have been linked to alterations in retina and brain function. These functional effects are presumed to follow from the biochemical consequences of modifying membrane PUFA content; known effects include modifications in membrane fludity, in the activities of membrane‐associated, functional proteins (transporters, receptors, enzymes), and in the production of important signaling molecules from oxygenated linoleic and α‐linolenic acid derivatives. However, despite the demonstration that central nervous system function changes when dietary PUFA intake is altered, and that in general, membrane PUFA content influences membrane functions, little work has focused specifically on brain and retina to reveal the underlying biochemical bases for such effects. This review examines this issue, looking at known effects of dietary PUFA on neurons in both the central and peripheral nervous systems, and attempts to identify some approaches that might promote productive investigation into the underlying mechanisms relating changes in dietary PUFA intake to alterations in neuronal and overall nervous system functioning.
Statistical considerations in infant nutrition trials
Authors: Gore Sheila M. 
Published: November 2006

AbstractInfant nutrition trials usually require developmental follow‐up, often to 18 mon, and sometimes beyond reading ability at age 7 yr. They are therefore logistically complex and costly, and should be conducted to a high statistical standard. With examples, we focus on: good practice in nutrition trials and the goal of a common protocol; how to set plausible trial targets and to work out trial size accordingly; statistical observations on assessing visual maturation; and methods of randomization, including the method known as minimization, which can be adapted to select more appropriately a comparison cohort of breast‐fed infants. We end with discussion of analysis and reporting standards, including the give‐aways (or tell‐tale signs) to be on the look out for. A Cochrane Collaboration for systematic review of randomized trials of infant nutrition is proposed.
Biological effects and safety issues related to long‐chain polyunsaturated fatty acids in infants
Authors: Heird William C. 
Published: November 2006

AbstractThe purpose of this workshop at the American Oil Chemists’ Society Symposium, “PUFA in Infant Nutrition: Consensus and Controversies”, was to enumerate the safety issues raised by the prospect of supplementing infant formulas with long‐chain polyunsaturated fatty acids (LC‐PUFA), to evaluate the evidence that these concerns are problematical, or theoretically problematical, and to identify the safety issues most in need of resolution. This was approached by reviewing briefly the known biological effects of LC‐PUFA and how these effects might give rise to concerns about safety of LC‐PUFA as components of infant formulas. Some of these issues were then discussed in more detail by invited participants, all of whom had submitted abstracts concerning the issue discussed. The pertinent aspects of all issues discussed during the workshop are summarized. In addition, since the symposium was held over 2 yr ago, an addendum summarizing additional data reported since the symposium that either support or refute issues discussed during the workshop also is included.
Recent advances in brain cholesterol dynamics: Transport, domains, and Alzheimer's disease
Authors: Wood W. Gibson , Schroeder Friedhelm , Avdulov Nicolai A. , Chochina Svetlana V. , Igbavboa Urule 
Published: November 2006

AbstractMajor advances in understanding cholesterol dynamics and the role that cholesterol plays in vascular disease have recently been made. The brain is an organ that is highly enriched in cholesterol, but progress toward understanding brain cholesterol dynamics has been relatively limited. This review examines recent contributions to the understanding of brain cholesterol dynamics, focusing on extracellular and intracellular lipid carrier proteins, membrane cholesterol domains, and emerging evidence linking an association between cholesterol dynamics and Alzheimer's disease.
Evidence that the trans‐10,cis‐12 isomer of conjugated linoleic acid induces body composition changes in mice
Authors: Park Yeonhwa , Storkson Jayne M. , Albright Karen J. , Liu Wei , Pariza Michael W. 
Published: November 2006

AbstractWe investigated the effects of conjugated linoleic acid (CLA) preparations, which were enriched for the cis‐9,trans‐11 CLA isomer or the trans‐10,cis‐12 CLA isomer, on body composition in mice. Body composition changes (reduced body fat, enhanced body water, enhanced body protein, and enhanced body ash) were associated with feeding the trans‐10,cis‐12 CLA isomer. In cultured 3T3‐L1 adipocytes, the trans‐10,cis‐12 isomer reduced lipoprotein lipase activity, intracellular triacylglycerol and glycerol, and enhanced glycerol release into the medium. By contrast, the cis‐9,trans‐11 and trans‐9,trans‐11 CLA isomers did not affect these biochemical activities. We conclude that CLA‐associated body composition change results from feeding the trans‐10,cis‐12 isomer.
Changes in body composition in mice during feeding and withdrawal of conjugated linoleic acid
Authors: Park Yeonhwa , Albright Karen J. , Storkson Jayne M. , Liu Wei , Cook Mark E. , Pariza Michael W. 
Published: November 2006

AbstractTwo experiments were conducted. In Experiment 1, 8‐wk‐old mice were fed control diet or diet supplemented with 0.5% conjugated linoleic acid (CLA) to study the effect of CLA on body composition (CLA: 40.8–41.1% c‐9,t‐11 isomer, 43.5–44.9% t‐10,c‐12 isomer). The data for CLA‐fed mice vs. controls described parallel but significantly distinct responses for both absolute and relative changes in body fat mass (reduced in CLA‐fed mice) and for relative changes in whole body protein and whole body water (both of which were increased in CLA‐fed mice). In the CLA‐fed mice, the effect on whole body protein appeared to precede the reduction in body fat mass. In Experiment 2, weanling mice were fed control diet or diet supplemented with 0.5% CLA for 4 wk (test group), at which time all mice were fed control diet devoid of added CLA. The test group exhibited significantly reduced body fat and significantly enhanced whole body water relative to controls at the time of diet change. Time trends for changes in relative body composition were described by parallel lines where the test group exhibited significantly less body fat but significantly more whole body protein, whole body water, and whole body ash than controls. Tissue CLA levels declined following the withdrawal of CLA from the diet. In skeletal muscle of mice fed CLA‐supplemented diet, the t‐10,c‐12 isomer was cleared significantly faster than the c‐9,t‐11 CLA isomer.
Activation of acyl‐CoA cholesterol acyltransferase: Redistribution in microsomal fragments of cholesterol and its facilitated movement by methyl‐β‐cyclodextrin
Authors: Cheng Donghui , Tipton Carl L. 
Published: November 2006

AbstractAcyl‐CoA cholesterol acyltransferase (ACAT) (EC 2,3,1.26) in the yolk sac membrane of chicken eggs plays an important role in the transport of lipids, which serve as both structural components and as an energy source during embryogenesis. ACAT from the yolk sac membrane of chicken eggs 16 d after fertilization has higher activity and better stability than its mammalian liver counterpart. During our study of the avian enzyme, ACAI was found to be activated up to twofold during storage at 4°C. The activation was investigated, and data suggest that redistribution of cholesterol within microsomal vesicles leads to the increase. Methyl‐β‐cyclodextrin (MβCD) increases activation an additional twofold, possibly by facilitating the movement of cholesterol within microsomal fragments and allowing redistribution of cholesterol in lipid bilayers to a greater extent. Treatment of microsomes with MβCD removes cholesterol from the membranes. Controlled amounts of cholesterol can be restored to the membranes by mixing them with cholesterol‐phosphatidylcholine liposomes in the presence of MβCD. Under these conditions, the plot of ACAT vs. cholesterol mole fraction in the liposomes is sigmoidal. The finding that MβCD can enhance cholesterol transfer between liposomes and microsomes and reduce the limitation of slow movement et nonpolar molecules in aqueous media should make cyclodextrins more useful in in vitro studies of apolar molecule transport between membrane vesicles.
Transformation of bile acids and sterols by clostridia (fusiform bacteria) in Wistar rats
Authors: Uchida Kiyohisa , Satoh Takashi , Narushima Seiko , Itoh Kikuji , Takase Haruto , Kuruma Kazuo , Nakao Hiroyuki , Yamaga Nobuo , Yamada Kazuo 
Published: November 2006

AbstractThe effects on bile acid and sterol transformation of clostridia (fusiform bacteria), the dominant intestinal bacteria in rodents (ca. 1010 counts per g wet feces) were examined in Wistar rats. After inoculation of clostridia into germ‐free rats and into rats previously inoculated solely with Escherichia coli, most of the endogenous bile acids were deconjugated, and cholic acid and chenodeoxycholic acid were 7α‐dehydroxylated to deoxycholic acid and lithocholic acid, respectively. Tauro‐β‐muricholic acid, another major bile acid in rats, was deconjugated, but only part of it (ca. 30%) was transformed into hyodeoxycholic acid. Cholesterol and sitosterol were also reduced to coprostanol and sitostanol, respectively. Escherichia coli transformed neither bile acids nor sterols. These data suggest that clostridia play an imporant role in the formation of secondary bile acids and coprostanol in rats.
White adipose tissue fatty acids of alpine marmots during their yearly cycle
Authors: Cochet Nathalie , Georges Bruno , Meister Roger , Florant Gregory L. , Barré Hervé 
Published: November 2006

AbstractAlpine marmots (Marmota marmota) were maintained on a laboratory diet, and the fatty acid composition of gonadal and subcutaneous whilte adipose tissues (WAT) was studied during a yearly cycle. Fatty acids (FA) released from isolated adipocytes were also identified after stimulation of in vitro lipolysis. Analysis of the FA composition of WAT depots showed that marmot WAT mainly contained monounsaturated FA(65%, mostly oleic, acid, 18:1n‐9) although laboratory food contained 45% of linoleic acid (18:2n‐6) and only 21% of 18:1n‐9. During stimulated lipolysis, saturated FA were preferentially released from isolated adipocytes whereas unsaturated FAs were retained. Despite this selective release of FA from isolated WAT cells in vitro, and despite the FA composition of the food, marmots maintained a constant FA composition in both WAT depots throughout the year. Six months of hibernation and fasting as well as an intense feeding period did not affect this composition. The potential adaptive benefit of such regulation of WAT composition, based on a high level of monounsaturated FA, might be to maintain fat with appropriate physical properties allowing animals to accommodate to and survive the wide range of body temperatures experienced during hibernation.
Fatty acid composition of 19 species of fish from the black sea and the Marmara Sea
Authors: Tanakol Refik , Yazici Zeliha , Şener Erdal , Sencer Ergin 
Published: November 2006

AbstractEvidence suggests that differences in fatty acid composition among various fish species may be due to differences in diet or to environmental factors such as temperature, salinity, and depth at which the fish are caught. The beneficial effects of a diet containing fish on cardiovascular or other diseases have been associated with their high content of eicosapentaenoic (20∶5n‐3) and docosahexaenoic (22∶6n‐3) acids. In this study we analyzed the fatty acid composition of the flesh of 18 different species of marine fish and of cultured rainbow trout. The fish were obtained from the Black and the Marmara Seas, both of which have unique biological and ecological systems as well as eutrophication and pollution. The contents of 20∶5n‐3 and 22∶6n‐3 in the marine fish ranged from 4.2 to 13.3 wt% of total fatty acids, and from 6.6 to 40.8 wt%, respectively. The most important differences from other studies on oceanic fish were the tendencies toward higher percentages of 16∶0 and 22∶6n‐3. The n‐3 series of polyunsaturated fatty acids were present as 32.4±1.9% of the total fatty acids. The present study suggests that mature and immature Pomatomus saltator, as well as Engraulis encrasicolus, Mullus surmuletus, Sardina pilchardus, Mugil cephalus, and Sarda sarda may be preferred for the Turkish diet as a result of their high 20∶5 n‐3 and 22∶6 n‐3 contents. The cultured rainbow trout Oncorhynchus mykiss is not as good a source of n‐3 fatty acids as are the marine fish.
Synthetic routes to lipidic diamines and amino alcohols: A class of potential antiinflammatory agents
Authors: Kokotos George , Constantinou‐Kokotou Violetta , Noula Caterina , Hadjipavlou‐Litina Dimitra 
Published: November 2006

AbstractSimple and efficient methods for the synthesis of lipidic amino alcohols and diamines are described in this paper. Lipidic 2‐amino alcohols and 1,3‐diamines can be synthesized starting from synthetic lipidic α‐amino acids. Alternatively, commercially available lipidic 1,2‐diols may be used as starting material for the synthesis of 2‐amino alcohols. Initial experiments on the in vivo antiinflammatory activity of the compounds synthesized gave promising results.
Docosahexaenoic acid ingestion inhibits natural killer cell activity and production of inflammatory mediators in young healthy men
Authors: Kelley D. S. , Taylor P. C. , Nelson G. J. , Schmidt Perla C. , Ferretti Aldo , Erickson Kent L. , Yu Rina , Chandra Ranjit K. , Mackey B. E. 
Published: November 2006

AbstractThe purpose of this study was to examine the effects of feeding docosahexaenoic acid (DHA) as triacylglycerol on the fatty acid composition, eicosanoid production, and select activities of human peripheral blood mononuclear cells (PBMNC). A 120‐d study with 11 healthy men was conducted at the Metabolic Research Unit of Western Human Nutrition Reach Center. Four subjects (control group) were fed the stabilization diet throughout the study; the remaining seven subjects were fed the basal diet for the first 30 d, followed by 6 g DHA/d for the next 90 d. DHA replaced an equivalent amount of linoleic acid; the two diets were comparable in their total fat and all other nutrients. Both diets were supplemented with 20 mg d α‐tocopherol acetate per day. PBMNC fatty acid composition and eicosanoid production were examined on day 30 and 113; immune cell functions were tested on day 22, 30, 78, 85, 106, and 113. DHA feeding increased its concentration from 2.3 to 7.4 wt% in the PBMNC total lipids, and decreased arachidonic acid concentration from 19.8 to 10.7 wt%. It also lowered prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) production, in response to lipopolysaccharide, by 60–75%. Natural killer cell activity and in vitro secretion of interleukin‐1β and tumor necrosis factor α were significantly reduced by DHA feeding. These parameters remained unchanged in the subjects fed the control diet. B‐cell functions as reported here and T‐cell functions that we reported previously were not altered by DHA feeding. Our results show that inhibitory effects of DHA on immune cell functions varied with the cell type, and that the inhibitory effects are not mediated through increased production of PGE2 and LTB4.
Fatty acid profile of buccal cheek cell phospholipids as an index for dietary intake of docosahexaenoic acid in preterm infants
Authors: Hoffman Dennis R. , Birch Eileen E. , Birch David G. , Uauy Ricardo 
Published: November 2006

AbstractCheek cells (buccal epithelia) were utilized as a noninvasive index of fatty acid status in a study of the effects of n−3 long chain polyunsaturated fatty acid supplementation on visual function in preterm infants. The fatty acid profile of cheek cell phospholipids was directly correlated with the dietary docosahexenoic acid (DHA) intake of infants receiving: (i) primarily human milk; (ii) n−3 fatty acid‐deficient, corn oil‐based, commercial formula (CO); (iii) α‐linolenic acid‐enriched, soy oilbased, commercial formula; or (iv) experimental formula enriched with soy and marine oils providing a DHA level equivalent to that in human milk. In a subset of infants with complete cheek cell fatty acid profiles and visual function assessments, preterm infants at both 36 wk (n=63) and 57 wk (n=45) postconceptional age had significantly (P<0.0005) reduced cheek cell phospholipid DHA levels in the n−3‐dificient, CO‐fed group compared to the other diet groups. The DHA content in cheek cell phospholipids was highly correlated (P<0.0005) with that of both red blood cell lipids and plasma phospholipids at the 36‐and 57‐wk time points. The DHA content in cheek cell lipids of infants at 36 wk was significantly correlated with electroretinographic responses (r=−0.29; P<0.03) and visual acuity (r=−0.31; P<0.02) as measured by visual‐evoked potentials (VEP). Cheek cell DHA was highly correlated (r=−0.57; P<0.0005) with VEP acuity at the 57‐wk time point. These results suggest that the fatty acid profile of cheek cells is a valid index of essential fatty acid status, can be monitored frequently, and is associated with functional parameters in infants.
Acyl‐CoA synthetase activity in liver microsomes from calcium‐deficient rats
Authors: Marra Carlos A. , de Alaniz María J. T. 
Published: November 2006

AbstractA study on the kinetic properties of the nonspecific acyl‐coenzyme A (CoA) synthetase activity in liver microsomal vesicles from both normal and calcium‐deficient Wistar rats was carried out. After a 65‐d treatment, the calcium‐deficient diet reflected a 75% increase in the synthetase activity with respect to control animals. The apparent Vm was significantly enhanced, while the Km remained unchanged. We also provided experimental evidence about various fatty acids of different carbon length and unsaturation which depressed the biosynthesis of palmitoyl‐CoA following different behaviors in control or calcium‐deprived liver microsomes. In addition, we studied in detail the inhibition reflected by stearic, α‐linolenic, or arachidonic acids, in the biosynthesis of palmitoyl‐CoA in microsomal suspensions either from control or hypocalcemic rats. In control microsomes, stearic acid produced a pure competitive effect, while the other fatty acids followed a mixed‐type inhibition. The competitive effect of stearic acid was not observed in calcium‐deprived microsomes. At the same time, a mixed‐type inhibition produced by either α‐linolenic or arachidonic acid was diminished in deprived microsomes due to an increase in the noncompetitive component (αKi). These changes observed in apparent kinetic constants (Km, Vm, Ki, and αKi), as determined by Lineweaver‐Burks and Dixon plots, were attributed to the important alterations in the physicochemical properties of the endoplasmic reticulum membranes induced by the calcium‐deficient diet. The solubilization of the enzyme activity from both types of microsomes demonstrated that the kinetic behavior of the enzyme depends on the microenvironment in the membrane, and that the calcium ion plays a crucial role in determining the alterations observed.