Showing papers on "Fatty acid published in 2008"
TL;DR: It is shown that a major factor is the total amount of fat and that phospholipid, where 18:2n-6 is located, declines as a proportion of muscle lipid and the proportion of neutral lipid, with its higher content of saturated and monounsaturated fatty acids, increases.
2,116 citations
TL;DR: Target metabolomics finds that obesity-related insulin resistance in skeletal muscle is characterized by excessive beta-oxidation, impaired switching to carbohydrate substrate during the fasted-to-fed transition, and coincident depletion of organic acid intermediates of the tricarboxylic acid cycle.
1,739 citations
TL;DR: Analysis of evidence from a wide variety of cross-sectional and intervention studies confirms that fatty acid biomarkers can complement dietary assessment methodologies and have the potential to be used more quantitatively.
1,122 citations
TL;DR: This article identified GOAT (Ghrelin O-Acyltransferase), a polytopic membrane-bound enzyme that attaches octanoate to serine-3 of ghrelin.
1,101 citations
TL;DR: In this article, the authors classified polyunsaturated fatty acids (PUFAs) in n-3 fatty acids and n-6 fatty acids, and in westernized diet the predominant dietary PUFAs are n- 6 fatty acids.
1,087 citations
TL;DR: Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and by releasing α-linolenic (18:3) from membrane lipids, the precursor molecule for phyto-oxylipin biosynthesis.
Abstract: Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and by releasing α-linolenic (18:3) from membrane lipids. The modification of membrane fluidity is mediated by changes in unsaturated fatty acid levels, a function provided in part by the regulated activity of fatty acid desaturases. Adjustment of membrane fluidity maintains an environment suitable for the function of critical integral proteins during stress. α-Linolenic acid, released from membrane lipid by regulated lipase activity, is the precursor molecule for phyto-oxylipin biosynthesis. The modulation of chloroplast oleic acid (18:1) levels is central to the normal expression of defense responses to pathogens in Arabidopsis. Oleic (18:1) and linolenic (18:2) acid levels, in part, regulate development, seed colonization, and mycotoxin production by Aspergillus spp.
679 citations
TL;DR: This review focuses on transcription factors such as sterol-regulatory-element-binding protein-1c and peroxisome proliferator-activated receptor alpha, which promote either hepatic fatty acid synthesis or oxidation.
Abstract: The liver plays a key role in lipid metabolism. Depending on species it is, more or less, the hub of fatty acid synthesis and lipid circulation through lipoprotein synthesis. Eventually the accumulation of lipid droplets into the hepatocytes results in hepatic steatosis, which may develop as a consequence of multiple dysfunctions such as alterations in beta-oxidation, very low density lipoprotein secretion, and pathways involved in the synthesis of fatty acids. In addition an increased circulating pool of non-esterified fatty acid may also to be a major determinant in the pathogenesis fatty liver disease. This review also focuses on transcription factors such as sterol-regulatory-element-binding protein-1c and peroxisome proliferator-activated receptor alpha, which promote either hepatic fatty acid synthesis or oxidation.
665 citations
TL;DR: This review focuses on the chemical structure of the polysorbates, factors influencing micelle formation and factors and excipients influencing stability and degradation of thepolyethylene and fatty acid ester linkages.
638 citations
TL;DR: Significant evidence is available to conclude that maternal fatty acid nutrition is important to DHA transfer to the infant before and after birth, with short and long-term implications for neural function.
557 citations
TL;DR: Together, the data provide evidence that Gpr40 modulates FFA-stimulated insulin secretion from β-cells not only directly but also indirectly via regulation of incretin secretion and suggest a conserved role for Ipf1/Pdx1 and GPR40 in F FA-mediated secretion of hormones that regulate glucose and overall energy homeostasis.
Abstract: OBJECTIVE: The G-protein-coupled receptor Gpr40 is expressed in beta-cells where it contributes to free fatty acid (FFA) enhancement of glucose-stimulated insulin secretion. However, other sites of ...
543 citations
TL;DR: Dietary phospholipids increase the efficiency of transport of dietary fatty acids and lipids from the gut to the rest of the body possibly through enhanced lipoprotein synthesis.
TL;DR: In this article, the zinc stearate immobilized on silica gel (ZS/Si) was the most effective catalyst in simultaneously catalyzing the transesterification of triglycerides and esterification of free fatty acid (FFA) present in WCO to methyl esters.
Abstract: Various solid acid catalysts were evaluated for the production of biodiesel from low quality oil such as waste cooking oil (WCO) containing 15 wt.% free fatty acids. The zinc stearate immobilized on silica gel (ZS/Si) was the most effective catalyst in simultaneously catalyzing the transesterification of triglycerides and esterification of free fatty acid (FFA) present in WCO to methyl esters. The optimization of reaction parameters with the most active ZS/Si catalyst showed that at 200 °C, 1:18 oil to alcohol molar ratio and 3 wt.% catalysts loading, a maximum ester yield of 98 wt.% could be obtained. The catalysts were recycled and reused many times without any loss in activity.
TL;DR: The milk fatty acids are derived almost equally from two sources, the feed and the microbial activity in the rumen of the cow and the lipids in bovine milk are mainly present in globules as an oil-in-water emulsion.
Abstract: Milk fat contains approximately 400 different fatty acid, which make it the most complex of all natural fats The milk fatty acids are derived almost equally from two sources, the feed and the microbial activity in the rumen of the cow and the lipids in bovine milk are mainly present in globules as an oil-in-water emulsion Almost 70% of the fat in Swedish milk is saturated of which around 11% comprises short-chain fatty acids, almost half of which is butyric acid Approximately 25% of the fatty acids in milk are mono-unsaturated and 23% are poly-unsaturated with omega-6/omega-3 ratio around 23 Approximately 27% are trans fatty acids
TL;DR: By introducing four distinct genetic changes into the E. coli genome, this work has engineered an efficient producer of fatty acids and shows a high conversion efficiency of 4.8% of the carbon source into fatty acid products.
TL;DR: The results suggest that learning and cognitive behavior are related to brain DHA status, which, in turn, is related to the levels of themilk/dietary n‐3 fatty acids.
Abstract: Docosahexaenoic acid (DHA), an n-3 fatty acid, is rapidly deposited during the period of rapid brain development. The influence of n-3 fatty acid deficiency on learning performance in adult rats over two generations was investigated. Rats were fed either an n-3 fatty acid-adequate (n-3 Adq) or -deficient (n-3 Def) diet for three generations (F1-F3). Levels of total brain n-3 fatty acids were reduced in the n-3 Def group by 83 and 87% in the F2 and F3 generations, respectively. In the Morris water maze, the n-3 Def group showed a longer escape latency and delayed acquisition of this task compared with the n-3 Adq group in both generations. The acquisition and memory levels of the n-3 Def group in the F3 generation seemed to be lower than that of the F2 generation. The 22:5n-6/22:6n-3 ratio in the frontal cortex and dams' milk was markedly increased in the n-3 Def group, and this ratio was significantly higher in the F3 generation compared with the F2 generation. These results suggest that learning and cognitive behavior are related to brain DHA status, which, in turn, is related to the levels of the milk/dietary n-3 fatty acids.
TL;DR: It is proposed that this series of fatty acids, notably those of the omega 3 series, might act as indirect anti- rather than pro-oxidant in vascular endothelial cells, hence diminishing inflammation and, in turn, the risk of atherosclerosis and cardiovascular disease.
TL;DR: The hypothesis that precursor availability has an important role in ethyl ester production is supported and the expression level and activity of the fatty acid biosynthetic enzymes appear to be prime targets for flavor modification by alteration of process parameters or through strain selection.
Abstract: Volatile esters are responsible for the fruity character of fermented beverages and thus constitute a vital group of aromatic compounds in beer and wine. Many fermentation parameters are known to affect volatile ester production. In order to obtain insight into the production of ethyl esters during fermentation, we investigated the influence of several fermentation variables. A higher level of unsaturated fatty acids in the fermentation medium resulted in a general decrease in ethyl ester production. On the other hand, a higher fermentation temperature resulted in greater ethyl octanoate and decanoate production, while a higher carbon or nitrogen content of the fermentation medium resulted in only moderate changes in ethyl ester production. Analysis of the expression of the ethyl ester biosynthesis genes EEB1 and EHT1 after addition of medium-chain fatty acid precursors suggested that the expression level is not the limiting factor for ethyl ester production, as opposed to acetate ester production. Together with the previous demonstration that provision of medium-chain fatty acids, which are the substrates for ethyl ester formation, to the fermentation medium causes a strong increase in the formation of the corresponding ethyl esters, this result further supports the hypothesis that precursor availability has an important role in ethyl ester production. We concluded that, at least in our fermentation conditions and with our yeast strain, the fatty acid precursor level rather than the activity of the biosynthetic enzymes is the major limiting factor for ethyl ester production. The expression level and activity of the fatty acid biosynthetic enzymes therefore appear to be prime targets for flavor modification by alteration of process parameters or through strain selection.
TL;DR: This review describes several areas where plant oils can have a significant impact on the emerging bioeconomy and the types of fatty acids that are required in these various applications.
Abstract: The seed oils of domesticated oilseed crops are major agricultural commodities that are used primarily for nutritional applications, but in recent years there has been increasing use of these oils for production of biofuels and chemical feedstocks. This is being driven in part by the rapidly rising costs of petroleum, increased concern about the environmental impact of using fossil oil, and the need to develop renewable domestic sources of fuel and industrial raw materials. There is also a need to develop sustainable sources of nutritionally important fatty acids such as those that are typically derived from fish oil. Plant oils can provide renewable sources of high-value fatty acids for both the chemical and health-related industries. The value and application of an oil are determined largely by its fatty acid composition, and while most vegetable oils contain just five basic fatty acid structures, there is a rich diversity of fatty acids present in nature, many of which have potential usage in industry. In this review, we describe several areas where plant oils can have a significant impact on the emerging bioeconomy and the types of fatty acids that are required in these various applications. We also outline the current understanding of the underlying biochemical and molecular mechanisms of seed oil production, and the challenges and potential in translating this knowledge into the rational design and engineering of crop plants to produce high-value oils in plant seeds.
TL;DR: Fatty acid analysis of total cellular lipids showed that glycerol concentration increase in the growth medium somehow increased the cellular unsaturated fatty acids content of lipids.
Abstract: Raw glycerol, byproduct from bio-diesel production process, is used as carbon substrate in several biotechnological applications. Using Clostridium butyricum F2b, 47.1 g L−1 of 1,3-propanediol was produced in batch anaerobic cultures while substrate uptake rate (rS, expressed in g L−1 h−1) increased with increase in glycerol concentration in the medium. In continuous cultures, microbial behaviour was studied in transitory states after addition of 1,3-propanediol in the chemostat vessel. Microbial growth was not affected by the high 1,3-propanediol (which was added in the chemostat vessel) concentration, while butyric and acetic acids concentrations were increased. In a two-stage continuous culture, 43.5 g L−1 of 1,3-propanediol was produced with a total volumetric productivity of 1.33 g L−1 h−1. Yarrowia lipolytica ACA-DC 50109 was grown in nitrogen-limited aerobic cultures on raw glycerol and it exhibited remarkable biomass production even at high glycerol concentration media, while rS decreased with increase in glycerol concentration. Citric acid was produced after nitrogen depletion in the medium, with the highest quantity of 62.5 g L−1, and yield on glycerol consumed was 0.56 g g−1. Fatty acid analysis of total cellular lipids showed that glycerol concentration increase in the growth medium somehow increased the cellular unsaturated fatty acids content of lipids. Mortierella isabellina ATHUM 2935 exhibited satisfactory growth in nitrogen-limited aerobic cultures with raw glycerol used as sole substrate. When high initial glycerol quantities were employed (e.g. 100 g L−1), 4.4 g L−1 of lipid were accumulated corresponding to around 51% (wt/wt) of lipid in dry weight. rS constantly decreased with increase in glycerol concentration in the medium, and in all cases notable glycerol quantities remained unconsumed in the medium.
TL;DR: A pooled analysis of 4 U.S. epidemiologic studies showed that subjects in the highest intake group for nut consumption had an approximately 35% reduced risk of CHD incidence, and the reduction in total CHD death was due primarily to a decrease in sudden cardiac death.
Abstract: Epidemiologic and clinical trial evidence has demonstrated consistent benefits of nut and peanut consumption on coronary heart disease (CHD) risk and associated risk factors. The epidemiologic studies have reported various endpoints, including fatal CHD, total CHD death, total CHD, and nonfatal myocardial infarct. A pooled analysis of 4 U.S. epidemiologic studies showed that subjects in the highest intake group for nut consumption had an approximately 35% reduced risk of CHD incidence. The reduction in total CHD death was due primarily to a decrease in sudden cardiac death. Clinical studies have evaluated the effects of many different nuts and peanuts on lipids, lipoproteins, and various CHD risk factors, including oxidation, inflammation, and vascular reactivity. Evidence from these studies consistently shows a beneficial effect on these CHD risk factors. The LDL cholesterol-lowering response of nut and peanut studies is greater than expected on the basis of blood cholesterol-lowering equations that are derived from changes in the fatty acid profile of the diet. Thus, in addition to a favorable fatty acid profile, nuts and peanuts contain other bioactive compounds that explain their multiple cardiovascular benefits. Other macronutrients include plant protein and fiber; micronutrients including potassium, calcium, magnesium, and tocopherols; and phytochemicals such as phytosterols, phenolic compounds, resveratrol, and arginine. Nuts and peanuts are food sources that are a composite of numerous cardioprotective nutrients and if routinely incorporated in a healthy diet, population risk of CHD would therefore be expected to decrease markedly.
TL;DR: Long-chain nonesterified ("free") fatty acids and some of their derivatives and metabolites can modify intracellular production of reactive oxygen species (ROS) and be, at least partly, responsible for their proapoptotic effects in several types of cells.
TL;DR: It is shown that overexpression of the Arabidopsis LEAFY COTYLEDON1 (LEC1) gene causes globally increased expression of fatty acid biosynthetic genes, which are involved in key reactions of condensation, chain elongation, and desaturation of fatty Acid biosynthesis.
Abstract: In plants, fatty acids are de novo synthesized predominantly in plastids from acetyl-coenzyme A. Although fatty acid biosynthesis has been biochemically well studied, little is known about the regulatory mechanisms of the pathway. Here, we show that overexpression of the Arabidopsis (Arabidopsis thaliana) LEAFY COTYLEDON1 (LEC1) gene causes globally increased expression of fatty acid biosynthetic genes, which are involved in key reactions of condensation, chain elongation, and desaturation of fatty acid biosynthesis. In the plastidial fatty acid synthetic pathway, over 58% of known enzyme-coding genes are up-regulated in LEC1-overexpressing transgenic plants, including those encoding three subunits of acetyl-coenzyme A carboxylase, a key enzyme controlling the fatty acid biosynthesis flux. Moreover, genes involved in glycolysis and lipid accumulation are also up-regulated. Consistent with these results, levels of major fatty acid species and lipids were substantially increased in the transgenic plants. Genetic analysis indicates that the LEC1 function is partially dependent on ABSCISIC ACID INSENSITIVE3, FUSCA3, and WRINKLED1 in the regulation of fatty acid biosynthesis. Moreover, a similar phenotype was observed in transgenic Arabidopsis plants overexpressing two LEC1-like genes of Brassica napus. These results suggest that LEC1 and LEC1-like genes act as key regulators to coordinate the expression of fatty acid biosynthetic genes, thereby representing promising targets for genetic improvement of oil production plants.
TL;DR: The crystal structures of the ligand binding domain of PPARγ in complex with several oxidized fatty acids are described in this paper, showing differences with synthetic agonists that may have physiological relevance.
Abstract: PPARγ is a nuclear receptor that regulates metabolic homeostasis and whose physiological ligands are nitrated and oxidized fatty acids. The crystal structures of the ligand binding domain of PPARγ in complex with several oxidized fatty acids are now described, showing differences with synthetic agonists that may have physiological relevance.
TL;DR: It is argued that such studies have failed to provide an accurate assessment of the activity and of the distinct function of these enzymes in mammalian cells.
Abstract: Acyl-CoA synthetase enzymes are essential for de novo lipid synthesis, fatty acid catabolism, and remodeling of membranes. Activation of fatty acids requires a two-step reaction catalyzed by these enzymes. In the first step, an acyl-AMP intermediate is formed from ATP. AMP is then exchanged with CoA to produce the activated acyl-CoA. The release of AMP in this reaction defines the superfamily of AMP-forming enzymes. The length of the carbon chain of the fatty acid species defines the substrate specificity for the different acyl-CoA synthetases (ACS). On this basis, five sub-families of ACS have been characterized. The purpose of this review is to report on the large family of mammalian long-chain acyl-CoA synthetases (ACSL), which activate fatty acids with chain lengths of 12 to 20 carbon atoms. Five genes and several isoforms generated by alternative splicing have been identified and limited information is available on their localization. The structure of these membrane proteins has not been solved for the mammalian ACSLs but homology to a bacterial form, whose structure has been determined, points at specific structural features that are important for these enzymes across species. The bacterial form acts as a dimer and has a conserved short motif, called the fatty acid Gate domain, that seems to determine substrate specificity. We will discuss the characterization and identification of the different spliced isoforms, draw attention to the inconsistencies and errors in their annotations, and their cellular localizations. These membrane proteins act on membrane-bound substrates probably as homo- and as heterodimer complexes but have often been expressed as single recombinant isoforms, apparently purified as monomers and tested in Triton X-100 micelles. We will argue that such studies have failed to provide an accurate assessment of the activity and of the distinct function of these enzymes in mammalian cells.
TL;DR: Adjustments to cultivation conditions could serve as an efficient tool for manipulation of yield and relative content of arachidonic acid in P. incisa due to greater increase in biomass.
Abstract: The effects of light and nitrogen deficiency on biomass, fatty acid content and composition were studied in Parietochloris incisa, the unicellular freshwater chlorophyte accumulating very high amounts of arachidonic-acid-rich triacylglycerols. P. incisa cultures grown on complete nutrient medium and under high light (400 μmol photons m− 2 s−1) showed the highest rate of growth in comparison to medium (200 μmol photons m−2 s−1) and low (35 μmol photons m−2 s−1) light intensity. Cultures grown under high light (on complete BG-11 medium) attained higher volumetric contents of total fatty acids and arachidonic acid due to greater increase in biomass. Nitrogen starvation brought about a strong increase in the arachidonic acid proportion of total fatty acids. Thus, adjustments to cultivation conditions could serve as an efficient tool for manipulation of yield and relative content of arachidonic acid in P. incisa. The significance of the changes in lipid metabolism for adaptation of P. incisa to high-light stress and nitrogen deficiency is also discussed.
TL;DR: In this article, an attempt has been made to use waste tallow as low cost sustainable potential feed stock for biodiesel production and the effect of various process parameters such as amount of catalyst, temperature and time on biodiesel consumption was investigated.
TL;DR: The cumulative consequences of VPA therapy in inborn errors of metabolism (IEMs) and the importance of recognizing an underlying IEM in cases of Vpa-induced steatosis and acute liver toxicity are two different concepts that will be emphasized.
Abstract: Valproic acid (VPA; 2-n-propylpentanoic acid) is widely used as a major drug in the treatment of epilepsy and in the control of several types of seizures. Being a simple fatty acid, VPA is a substrate for the fatty acid β-oxidation (FAO) pathway, which takes place primarily in mitochondria. The toxicity of valproate has long been considered to be due primarily to its interference with mitochondrial β-oxidation. The metabolism of the drug, its effects on enzymes of FAO and their cofactors such as CoA and/or carnitine will be reviewed. The cumulative consequences of VPA therapy in inborn errors of metabolism (IEMs) and the importance of recognizing an underlying IEM in cases of VPA-induced steatosis and acute liver toxicity are two different concepts that will be emphasized.
TL;DR: In this paper, the liquid phase deoxygenation reaction of unsaturated renewables has been investigated in a semi-batch reactor with a Pd/C catalyst under constant pressure and temperature in the following domain.
TL;DR: In this article, the direct esterification reaction of triglycerides to biodiesel was studied and the effects of the main variables involved in the process, reaction temperature, amount of catalyst, initial amount of free fatty acid and the molar ratio alcohol/oil were analyzed.
Abstract: Biodiesel is one of the new possible substitutes of regular fuel for engines and is produced from different vegetable oils or animal fats. The main reaction involved is the transesterification of triglycerides into esters. When an acid oil, such as spent or waste oil, is used, the amount of free fatty acids range from 3% to 40%, and another reaction takes place simultaneously with the transesterification, the direct esterification of the free fatty acid. In this work, the direct esterification reaction of triglycerides to biodiesel was studied and the effects of the main variables involved in the process, reaction temperature, amount of catalyst, initial amount of free fatty acid and the molar ratio alcohol/oil, were analyzed. For this investigation, we employed a model acid oil produced by mixing pure oleic acid with refined sunflower oil. Ethanol was used in the experiments instead of methanol since it is less toxic and safer to handle. Sulfuric acid was employed as catalyst because of its advantages compared with conventional homogeneous catalysts (NaOH). It was found that ethanol and sulfuric acid were suitable to perform not only the transesterification reaction but also the direct esterification reaction to increase biodiesel production of the process.
TL;DR: If the compositions of the blended biodiesels are determined, it is possible to predict their oxidation stability and CFPP and to determine the blending ratios of biodiesel mixture having the specified properties.