Tesi: "Fatty acid"

1

Turk, Stacey N. "Fatty Acid Carcass Mapping". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2008-05-4.

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2

West, Annette Lucy. "Studies of fatty acid status in humans given omega-3 fatty acid supplements". Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/405280/.

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3

Nachtschatt, Matthias Hannes. "Investigating the structure-function relationships of the ∆5 fatty acid desaturase and the cyclopropane fatty acid synthase". Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/133997/1/Matthias%20Hannes_Nachtschatt_Thesis.pdf.

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Abstract (sommario):

Moving from a fossil fuel-based linear economy to a renewable circular economy is a key challenge facing industry, society and our natural environment. An alternative to crude oil derived petrochemicals are oleochemicals that are produced by plants or microorganisms. Matthias's research focused on exploring biochemical tools to create novel oleochemicals as renewable feedstocks for the chemical industry. Specifically, his thesis contributed to our understanding of fatty acid modification processes within biological systems. Matthias's work is a fundamental contribution to further the renewable resource revolution.

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4

Farrell, Emma K. "Biosynthesis of fatty acid amides". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/1629.

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Primary fatty acid amides (PFAMs) and N-acylglycines (NAGs) are important signaling molecules in the mammalian nervous system, binding to many drug receptors and demonstrating control over sleep, locomotor activity, angiogenesis, vasodilatation, gap junction communication, and many other processes. Oleamide is the best-studied of the PFAMs, while the in vivo activity of the others is largely unstudied. Even less is known about the NAGs, as their discovery as novel compounds is much more recent due to low endogenous levels. Herein is described extraction and quantification techniques for PFAMs and NAGs in cultured cells and media using solvent extraction combined with solid phase extraction (PFAM) or thin layer chromatography (NAG), followed by gas chromatography-mass spectroscopy to isolate and quantify these lipid metabolites. The assays were used to examine the endogenous amounts of a panel of PFAMs as well as the conversion of corresponding free fatty acids (FFAs) to PFAMs over time in several cell lines. The cell lines demonstrated the ability to convert all FFAs, including a non-natural FFA, and an ethanolamine to the corresponding PFAM. Different patterns of relative amounts of endogenous and FFA-derived PFAMs were observed in the cell lines tested. Essential to identifying therapeutic targets for the many disorders associated with PFAM signaling is understanding the mechanism(s) of PFAM and NAG biosynthesis. Enzyme expression studies were conducted to determine potential metabolic enzymes in the model cell lines in an attempt to understand the mechanism(s) of PFAM biosynthesis. It was found that two of the cell lines which show distinct metabolisms of PFAMs also demonstrate unique enzyme expression patterns, and candidate enzymes proposed to perform PFAM and NAG metabolism are described. RNAi knockdown studies revealed further information about the metabolism of PFAMs and calls into question the recently proposed involvement of cytochrome c. Isotopic labeling studies showed there are two pathways for PFAM formation. A novel enzyme is likely to be involved in formation of NAGs from acyl-CoA intermediates.

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5

Taylor, George. "Fatty acid metabolism in cyanobacteria". Thesis, University of Exeter, 2012. http://hdl.handle.net/10871/9363.

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Abstract (sommario):

With crude oil demand rising and supplies being depleted, alternative energy, specifically biofuels, are of intense scientific interest. Current plant crop based biofuels suffer from several problems, most importantly the use of land needed for food. Cyanobacteria offer a solution to this problem as they do not compete with land for food and produce hydrocarbons that can be used as biofuels. Upon examination of metabolic pathways competing with hydrocarbon synthesis, it appeared that cyanobacteria lacked the major fatty acid degradative metabolic pathway β-oxidation, generally thought to be a universally occurring pathway. Lack of this pathway in cyanobacteria was confirmed by employing a range of analytical techniques. Bioinformatic analysis suggested that potential enzymes with β-oxidation activity were involved in other metabolic pathways. A sensitive assay was set up to detect acyl- CoAs, the substrates of β-oxidation, using liquid chromatography triple quadrupole mass spectrometry. None could be detected in cyanobacteria. No enzymatic activity from the rate-limiting acyl-CoA dehydrogenase/oxidase could be detected in cyanobacterial extracts. It was found that radiolabeled fatty acids fed to cyanobacteria were utilised for lipid membranes as opposed to being converted to CO2 by respiration or into other compounds by the TCA cycle. An element of the β-oxidation pathway, E. coli acyl-CoA synthetase was ectopically expressed in a strain of cyanobacteria and implications of the introduction of acyl-CoA synthesis were assessed. Finally, the regulation of the fatty acid biosynthetic pathway was investigated. It was determined that under conditions of excess fatty acid, the transcription of acetyl-CoA carboxylase and enoyl-ACP reductase was repressed and acyl-ACP synthetase involved in fatty acid recycling was induced. These results were discussed in relation to fatty acid oxidation and hydrocarbon biosynthesis in other organisms.

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6

Rose, Philip. "Indices of fatty acid metabolism". Thesis, Sheffield Hallam University, 1992. http://shura.shu.ac.uk/20296/.

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During the fed state energy requirements are met by glycolysis of carbohydrates. When the stores of carbohydrates are diminished, for example during prolonged fasting, metabolism switches to that of fatty acids. Fatty acids are broken down by fi-oxidation within the mitochondrial matrix. Prolonged fasting results in the production of ketone bodies. These can also be used as an energy source by the brain. In defects of fatty acid metabolism where individual steps are inhibited or blocked, such as medium chain acyl-CoA dehydrogenase deficiency, an abnormal accumulation of the metabolites that lead up to the block, or their breakdown products, is often seen. Non-compensatory levels of metabolites following the site of the defect also occur. In the fed state, when flux through the defective fatty acid pathway is minimal, metabolic profiles can appear completely normal. It is therefore often necessary to induce metabolic stress before a full laboratory investigation can proceed. Interpretation of individual metabolite quantitations can often be difficult and a variation of 'normal values' according to metabolic state can lead to misinterpretation. Comparison between the concentrations of related metabolites along the fatty acid metabolic pathway may diminish the need for exact knowledge of the metabolic state and by correlation plotting could clearly identify abnormal relationships. This thesis describes an investigation into the efficacy of paired metabolite correlation plots in preliminary detection of defects in fatty acid metabolism. In certain inborn errors of fatty acid metabolism where the fi-oxidation cycle is affected, abnormal urine metabolite patterns have been used as diagnostic markers. Similar patterns have been reported in the urine of healthy newborns and termed generalised neonatal dicarboxylic aciduria177. This report documents an investigation of the connections between generalised neonatal dicarboxylic aciduria and a number of overlying factors (vis type of feed, gender, sibling history of sudden infant death syndrome and urine carnitine levels). Also discussed is the development of two laboratory assays. A radio-enzymatic method was developed and used to determine the levels of total, free and acyl carnitine in urine or blood. Suberyl, hexanoyl, and phenylpropionyl glycine in urine can be quantitated by use of stable isotope internal standards and gas chromatography / electron impact mode mass spectrometry. Synthesis and calibration of such internal standards is described. Finally, methods used to culture and store skin fibroblasts from biopsy samples are included as an appendix. These fibroblasts can then be used in various diagnostic tests such as carbon dioxide release and electron transfer flavoprotein enzyme analysis. The costs encountered during tissue culture could be avoided by medium term storage of the biopsy material prior to culture to await sufficient clinical evidence to merit such analyses. Preliminary results of extended cryogenic storage and viability of recovered specimens are also included.

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7

Kishino, Shigenobu. "Production of conjugated fatty acids by lactic acid bacteria". Kyoto University, 2005. http://hdl.handle.net/2433/86244.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第11617号
農博第1473号
新制||農||905(附属図書館)
学位論文||H17||N4010(農学部図書室)
UT51-2005-D366
京都大学大学院農学研究科応用生命科学専攻
(主査)教授清水昌, 教授加藤暢夫, 教授植田充美
学位規則第4条第1項該当

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8

Baker, Nancy Carol. "The Associations Among Dietary Fatty Acids, Plasma Fatty Acids, and Clinical Markers in Postmenopausal Women with Diabetes". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253666943.

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9

Batugedara, Hashini Maneesha. "Fatty acid metabolism in Saccharomyces cerevisiae and effects of fatty acid metabolites on neutrophil function". Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1526893.

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Abstract (sommario):

In the presence of arachidonic acid (AA), Saccharomyces cerevisiae produces prostaglandin E₂ (PGE₂). S. cerevisiae and its metabolites may be consumed in products manufactured using the yeast (e.g. beer). Neutrophils are immune cells present in the gastrointestinal (GI) tract during inflammation. As a lipid-signaling molecule, PGE₂ can potentially modify neutrophil functions and exacerbate pre-existing inflammation. As neutrophil migration is a hallmark of inflammation, we investigated the impact of PGE₂ on neutrophil chemotaxis. Chemotaxis assays were performed on neutrophils isolated from human whole blood using the chemotactic agents f-Met-Leu-Phe (fMLP) or interleukin-8 (IL-8). Neutrophil chemotaxis was concentration dependent as it was enhanced 3.5-fold at low concentrations of PGE₂ (0.1 nM-10 nM) and reduced 3.0-fold at higher concentrations of PGE₂ (100 nM).

The biochemical pathway utilized by S. cerevisiae to produce PGE₂ is unknown. Identifying enzymes that metabolize AA may direct approaches to reduce the impact that yeast PGE₂ may have on neutrophils. S. cerevisiae does not have genes homologous to those involved in mammalian AA metabolism. We employed RNAseq transcriptome sequencing to study the lipid biosynthetic pathway in S. cerevisiae and observed 1248 genes upregulated in yeast that were cultured in the presence of AA relative to yeast that were cultured without AA. Notably, genes that mediate beta-oxidation of fatty acids (Pot1, Pox1, Faa1 and Faa2) were upregulated up to 2.3-fold.

The results demonstrate that low concentrations of PGE₂ enhance neutrophil chemotaxis that is mediated by fMLP or IL-8, suggesting that PGE₂ may aid in recruiting neutrophils from regions that are distant to a site of inflammation. Once a higher concentration of PGE₂ is encountered by neutrophils, neutrophils may halt their migration and engage effector functions such as phagocytosis and superoxide production. Increased expression of genes involved with fatty acid metabolism points to enzymes that may utilize AA to produce PGE₂ in S. cerevisiae. Experiments testing PGE₂ levels in knock-out strains of yeast will identify genes involved in PGE₂ production. Results of this study have implications to reduce potential off-target effects caused by yeast PGE₂ in consumables.

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10

Murota, Kaeko. "INHIBTION OF DIETARY FATTY ACID ABSORPTION BY EXOGENOUS FATTY ACID DERIVATIVES IN THE SMALI INTESTINE". Kyoto University, 2001. http://hdl.handle.net/2433/150341.

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11

Mizutani, Masako. "Novel Fatty Acid Desaturases and Electron Transfer for Microsomal Fatty Acid Desaturation in Higher Plants". Kyoto University, 1999. http://hdl.handle.net/2433/181914.

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12

Nieuwenhoven, Franciscus Arnoldus van. "Heart fatty acid-binding proteins role in cardiac fatty acid uptake and marker for cellular damage /". Maastricht : Maastricht : Rijksuniversiteit Limburg ; University Library, Maastricht University [Host], 1996. http://arno.unimaas.nl/show.cgi?fid=6268.

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13

Campbell, Fiona M. "Long-chain fatty acid transport by the human placenta : the role of fatty acid-binding proteins". Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363738.

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Abstract (sommario):

The placenta is thought to play a vital role in the transfer of essential fatty (EFA) and their long-chain polyunsaturated derivatives (LCPUFA) from mother to the fetus. There is a preferential accumulation of these fatty acids from maternal to fetal tissues. However, little was known about the manner in which these nutrients preferentially traversed the placenta. This study investigated part of this placental transport mechanism. The results from these investigations demonstrated that the preferential transport of LCPUFA to the fetal circulation may at least be partially mediated by a preferential uptake system in the placenta involving a 40 kDa, placental membrane fatty acid binding protein (p-FABP_pm). This protein was found exclusively in the maternal facing microvillous membranes. It was characterised as different from previously identified ubiquitous FABP_pm by virtue of having a different pl value, different amino acid composition, no aspartate aminotransferase activity and a higher binding affinity for LCPUFA over non-essential fatty acids. The human choriocarcinoma cell line (BeWo) expressed a protein immunoreactive to anti-p-FABP_pmanti-serum. This anti-serum inhibited the binding of LCPUFA to placental membranes and the uptake of LCPUFA by BeWo cells, to a greater degree than it inhibited the uptake and binding of non essential fatty acids. In addition to p-FABP_pmthe existence of multiple types of both cytosolic (L-FABP and H-FABP) and membrane (FAT and FATP) fatty acid-binding proteins was demonstrated in placental cells. These proteins could play important roles in both the uptake of fatty acids by the placenta and in controlling the fate of fatty acids inside placental cells.

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14

Thambugala, Dinushika. "Analysis of genetic diversity and expression of genes involved in fatty acid composition in flax (Linum usitatissimum L.) and comparative genomic analysis of their loci". Theoretical and Applied Genetics, 2013. http://hdl.handle.net/1993/30665.

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Flax (Linum usitatissimum L.) is one of the richest plant sources of omega-3 fatty acids praised for their health benefits. In this study, the extent of the genetic variability for genes encoding stearoyl-ACP desaturase (SAD), fatty acid desaturase 2 (FAD2) and 3 (FAD3) was determined by sequencing the six paralogous genes from 120 flax accessions representing a broad range of germplasm including some EMS mutant lines. A total of 6 alleles for sad1 and sad2, 21 for fad2a, 5 for fad2b, 15 for fad3a and 18 for fad3b were identified. Deduced amino acid sequences of the alleles predicted 4, 2, 3, 4, 6, and 7 isoforms, respectively. Allele frequencies varied greatly across genes. Fad3a, with 110 SNPs and 19 indels, and fad3b, with 50 SNPs and 5 indels, showed the highest levels of genetic variation. While most of the SNPs and all the indels were silent mutations, both genes carried non-sense SNP mutations resulting in premature stop codons, a feature not observed in sad and fad2 genes. Some alleles and isoforms discovered in induced mutant lines were absent in the natural germplasm. Correlation of these genotypic data with fatty acid composition data of 120 flax accessions phenotyped in six field experiments revealed statistically significant correlations of some of the SAD and FAD isoforms on fatty acid composition, oil content and iodine value. The novel allelic variants and isoforms identified for the six desaturases will be a resource for the development of oilseed flax with unique and useful fatty acid profiles.
October 2015

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15

Cryle, Max Julian. "Fatty acid metabolism by cytochromes P450 /". [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19452.pdf.

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16

Atrafi, Avishan. "Frothing properties of fatty acid collectors". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52245.

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The gas dispersion and foaming properties of aqueous solutions of fatty acids of different hydrocarbon chain lengths were assessed through measurements of bubble size distributions, gas hold-up, foam volume and growth rate. The adsorption behavior of the tested fatty acids at the gas-solution interface was assessed and the results were supplemented by measurements of the partition of each surfactant between the bulk solution and foam phase as a result of continuous aeration. Two mechanisms of gas dispersion were identified depending on the pH and speciation of the tested solutions. Solutions of long chain fatty acids containing colloidal precipitates at low pH exhibited low surface tensions, and only a small decrease in bubble sizes was observed for such solutions compared to bubble sizes measured in water. This relatively small change in bubble sizes could theoretically be predicted based only on the corresponding change in the surface tension of the solutions. In contrast, true solutions of long chain fatty acids affected bubble sizes to a much greater extent even though their surface tension values were higher and in some cases comparable to the surface tension of water. A combination of the surface tension and surface tension gradient effects was found to be operative in this case. Experimental results strongly suggested that the associated acid species were more surface-active and more capable of reducing bubble sizes than the dissociated carboxylate anion. The ability of the surfactants to quickly generate a large foam volume was found to be a strong function of the chain length. Although bubble size measurements in bulk solution pointed towards similar gas dispersing abilities of fatty acids of different chain lengths, their foamabilities under the same conditions were remarkably enhanced by increasing chain length. Creation of large volumes of persistent foam was correlated with strong tendency to partition into the foam phase. Overall, the gas dispersing properties of fatty acids were comparable to those of a weak frother such as methyl isobutyl carbinol (MIBC), while only the foaming capabilities of hexanoate were similar to those of MIBC. Longer chain fatty acids were much stronger foaming agents than MIBC.
Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate

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17

Lippmeier, James Casey. "Fatty acid metabolism of marine microalgae". Thesis, University of Hull, 2007. http://hydra.hull.ac.uk/resources/hull:7014.

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Pathways for the biosynthesis of docosahexaenoic acid (DHA) and other polyunsaturated fatty acids (PUFA) were elucidated in two heterotrophic, marine microalgae; Schizochytrium sp. and Crypthecodinium cohnii. PUFA-requiring auxotrophs of both of these algae were created and used as tools for studying PUFA biosynthetic pathways. Additionally, equilibrium radio-labeling techniques were applied to algal cultures fed 14C-fatty acids. Both organisms were found to possess two distinct pathways for PUFA biosynthesis. One pathway, mediated by classical elongases and desaturases, was incomplete in both organisms and was not capable of complementing PUFA auxotrophic phenotypes or of producing PUFA de novo, but could produce DHA from simpler PUFA precursors. The second PUFA pathway in each organism was desaturase and elongase independent. In C. cohnii, this pathway was distinguished by a capacity to produce DHA from acetate, in a manner similar to that of Schizochytrium which was shown to employ a polyketide synthase (PKS) complex for primary DHA biosynthesis. Additionally, genes of the Schizochytrium PUFA-PKS were successfully expressed in transgenic yeast, which produced DHA. Candidates for genes encoding C. cohnii PUFA-PKS components and other genes of C. cohnii PUFA biosynthesis were identified and discussed.

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18

Eaton, Simon. "Regulation of fatty acid #beta#-oxidation". Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311443.

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19

Spurway, Tracy Deborah. "Control of hepatic fatty acid oxidation". Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283671.

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20

Jackson, Sandra. "Enzymes of mitochondrial fatty acid oxidation". Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283069.

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21

Sheridan, Mary T. "Studies of fatty acid binding protein". Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235759.

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22

Ghimire, Sandip. "Volatile Fatty Acid Production in Ruminants". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75306.

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Abstract (sommario):

Volatile fatty acids (VFA) are important products of ruminal fermentation. The VFA are not only the major source of energy to the ruminant animals but also influence methane production in the rumen. Therefore it is important to understand mechanism controlling VFA production and to depict VFA production in a model. This will allow us to devise strategies to enhance energy utilization and reduce methane production in ruminant livestock. An evaluation of a mechanistic model in predicting VFA production was conducted and equations were introduced into the model to improve the predictions. Later a continuous culture experiment was conducted to test the hypothesis on which those equations were based on. A mechanistic model -" Molly, was evaluated using a dataset with reported VFA production rates. The results of residual error analysis indicated that the root mean square prediction errors (RMSPE) were 63, 63, and 49% for acetate, propionate and butyrate, respectively. An assessment from two studies reporting VFA production revealed a potential of reducing errors of prediction by representing interconversion among VFA. In the second study, equations based on thermodynamics influence of pH and VFA concentration were introduced in the model to represent interconversion among VFA. The parameters for de novo VFA production and VFA absorption were re derived with (VFAInt) and without (BASE) the new interconversion equations. There were some improvements in the VFA concentration predictions but the improvements were both in VFAInt and BASE models. The RMSPE of VFA production were still above 50% for acetate, propionate and butyrate. The larger errors of predictions were attributed to measurement variation in VFA production literature, or possible incorrect rate constants for interconversion equations. Finally, a third study was conducted to assess the effect of pH, and VFA concentration on VFA and methane production in continuous culture. The treatments consisted of control, 20 mmol/d acetate infusion (INFAC), 7 mmol/d propionate infusion (INFPR), and low pH (LOWPH). Individual isotopes of acetate, propionate and butyrate were infused in the fermenters to estimate interconversions among VFA. With LOWPH treatment methane emission was reduced whereas production of propionate was increased. Hydrogen production was higher in INFAC indicating that some of the acetate could have been degraded to CO2 and H2. It was estimated that around 3 % of de novo acetate was converted to propionate and 9 % to butyrate. Exchange between propionate and butyrate was insignificant and below 1% of de novo production of either VFA. However, treatments did not affect interconversion rates among VFA. These results indicated that pH and VFA concentration do not have thermodynamic influence on VFA interconversion as hypothesized.
Ph. D.

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23

Zadravec, Damir. "Metabolic Significance of Fatty Acid Elongation". Doctoral thesis, Stockholm : Department of Physiology, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-34815.

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Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.
At the time of the doctoral defence, the following papers were unpublished and had status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Submitted. Paper 6: Manuscript. Härtill 6 uppsatser.

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24

Kim, Sang-Chul. "Functional Characterization of Plant Fatty Acid Amide Hydrolases". Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33177/.

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Fatty acid amide hydrolase (FAAH) terminates the endocannabinoid signaling pathway that regulates numerous neurobehavioral processes in animals by hydrolyzing a class of lipid mediators, N-acylethanolamines (NAEs). Recent identification of an Arabidopsis FAAH homologue (AtFAAH) and several studies, especially those using AtFAAH overexpressing and knock-out lines suggest that a FAAH-mediated pathway exists in plants for the metabolism of endogenous NAEs. Here, I provide evidence to support this concept by identifying candidate FAAH cDNA sequences in diverse plant species. NAE amidohydrolase assays confirmed that several of the proteins encoded by these cDNAs indeed catalyzed the hydrolysis of NAEs in vitro. Kinetic parameters, inhibition properties, and substrate specificities of the plant FAAH enzymes were very similar to those of mammalian FAAH. Five amino acid residues determined to be important for catalysis by rat FAAH were absolutely conserved within the plant FAAH sequences. Site-directed mutation of each of the five putative catalytic residues in AtFAAH abolished its hydrolytic activity when expressed in Escherichia coli. Contrary to overexpression of native AtFAAH in Arabidopsis that results in enhanced seedling growth, and in seedlings that were insensitive to exogenous NAE, overexpression of the inactive AtFAAH mutants showed no growth enhancement and no NAE tolerance. However, both active and inactive AtFAAH overexpressors displayed hypersensitivity to ABA, suggesting a function of the enzyme independent of its catalytic activity toward NAE substrates. Yeast two-hybrid screening identified Arg/Ser-rich zinc knuckle-containing protein as a candidate protein that physically and domain-specifically interacts with AtFAAH and its T-DNA knock-out Arabidopsis was hypersensitive to ABA to a degree similar to AtFAAH overexpressors. Taken together, AtFAAH appears to have a bifurcating function, via NAE hydrolysis and protein-protein interaction, to control Arabidopsis growth and interaction with phytohormone signaling pathways. These studies help to functionally define the group of enzymes that metabolize NAEs in plants, and further will expand the knowledge-base of lipid metabolism and signaling for manipulation of various physiological processes important to plant growth and responses to environmental stress.

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25

Peet, Daniel J. "Protein-bound fatty acids in mammalian hair fibres /". Connect to thesis, 1994. http://eprints.unimelb.edu.au/archive/00000641.

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26

Torkko, J. (Juha). "Characterization of mitochondrial 2-enoyl thioester reductase involved in respiratory competence". Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514270312.

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Abstract Maintenance of the mitochondrial respiratory chain complexes plays crucial role for the aerobic metabolism of the eukaryotes such as unicellular yeasts, for example, Saccharomyces cerevisiae as well as of human being. Mitochondrial respiratory function has been studied using the yeast S. cerevisiae as a model organism. Since yeast cells are also able to grow without respiration by fermentation, identification of the nuclear genes linked to respiratory function is possible by generation of nuclear gene deletions and testing for respiration-deficient phenotype of the yeast deletion strains id est for yeast cells only poorly or not at all growing on the media containing non-fermentable carbon sources. This study reports identification of a novel mitochondrial 2-enoyl thioester reductase from the yeasts Candida tropicalis and S. cerevisiae, Etr1p and Mrf1p, respectively. Examination of the function of these proteins in the respiration-deficient mrf1Δ strain from S. cerevisiae suggests that the reductase is involved in mitochondrial fatty acid synthesis (FAS type II) in the yeast. Site-directed mutagenesis of a conserved tyrosine in the catalytic site of the enzyme indicated that the 2-enoyl thioester reductase activity is critical for mitochondrial respiratory competence. In addition, subcellular localization to mitochondria was required for the complementation of the respiration-deficient phenotype of the yeast reductase deletion strain. The crystal structure for the Etr catalytic site mutant indicated the structural integrity of the mutant supporting the requirement of the tyrosine for the catalysis. Characterization of Etr crystal structures both in apo- and holo-forms containing NADPH established Etr as a member of novel subfamily of enoyl thioester reductases in the superfamily of medium-chain dehydrogenases/reductases (MDR). Two isoforms of Etr with the difference in three amino acids only are encoded by two distinct genes in C. tropicalis, whereas only single gene encodes the reductase functioning in the mitochondria in S. cerevisiae. The presence of two genes in C. tropicalis was taken as an example of genetic redundancy in this yeast, the two genes also shown to be expressed in slightly different ways under various carbon sources available for growth.

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27

Maisonet, Mildred, Ruby Yadav e Edward Leinaar. "Role Of Perfluorooctanoic Acid On Serum Fatty Acids, Nhanes, 2003-2004". Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/2.

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Background: Fatty acids (FA) have a role on energy storage and membrane formation. FA consists of an aliphatic chain with varying number of carbon and a carboxylic functional group. Perfluorooctanoic acid (PFOA) exhibits a similar structure to that of the FA. Given their structural resemblance, we hypothesized that alterations in FA metabolism could arise from competition with PFOA for endogenous FA binding sites in transport and with FA binding proteins. Objectives: Explore associations of serum concentrations of perfluorooctanoic acid (PFOA) with serum concentrations of linoleic (LA), eicosapentanoic (EPA), and docosapentanoic (DHA) acid in adults. Methods: We analyzed data from 1,829, 20-80 years old participants in the 2003–2004 National Health and Nutrition Examination Survey (NHANES). Linear regression models were used to estimate adjusted predicted means of the FA (in µmol/L) for quartiles of PFOA (in ng/mL) and explore linear trends. Results: Increasing concentrations of PFOA were not associated with adjusted predicted means of serum LA (Q1 3534, Q2 3445, Q3 3778, Q4 3399) (p trends=0.6460). Increasing concentrations of PFOA, however, were associated with increasing trends in adjusted predicted means of serum EPA (Q1 49.8, Q2 51.5, Q3 60.9, Q4 55.7).

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28

Bell, John Gordon. "Influences of dietary polyunsaturated fatty acids on tissue fatty acid composition and eicosanoid production in Atlantic salmon (Salmo salar)". Thesis, University of Stirling, 1996. http://hdl.handle.net/1893/26665.

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Abstract (sommario):

1. The literature has been reviewed with respect to the dietary intake and subsequent metabolism of polyunsaturated fatty acids (PUFA), of both the n-6 and n-3 series, in teleost fish. Particular emphasis has been made to the physiological roles of PUFA with respect to cell membrane function and eicosanoid production. 2. Atlantic salmon post-smolts were fed practical-type diets, based on fish meal, in three separate dietary experiments of 10-16 weeks duration. The first trial compared dietary lipid supplied either as fish oil (FO) or as sunflower oil (SO) with the diets having an n-3/n-6 PUFA ratio of 9.4 and 0.2 respectively. The second trial used diets formulated with blends of FO, SO, grape seed oil and safflower oil to provide linoleic acid at 10, 25 and 45% of total dietary fatty acids. The third trial was similar to the first but with an additional diet in which the lipid component was supplied by linseed oil (LO). All diets satisfied the nutritional requirements of salmonid fish for n-3 PUFA. There were no statistically significant differences in final weights between dietary treatments in the third trial. However, in the second trial fish fed the intermediate level of linoleic acid (25%) attained a significantly higher final weight compared to both other treatments while fish fed the highest level of linoleic acid (45%) had significantly lower final weights compared to both other treatments. In the first trial the effect of diet on growth (weight gain) could not be ascertained as the initial weights of the fish were significantly different. 3. A number of fish fed SO developed severe cardiac lesions which caused thinning of the ventricular wall and heart muscle necrosis. In addition the fish fed diets containing SO were susceptible to a transportation-induced shock syndrome that resulted in 30% mortality. 4. Incorporation of linoleic acid (18:2n-6) into membrane phospholipids increased in response to dietary intake with fish fed SO having increased levels of 18:2n-6 (up to 15-fold), 20:2n-6 (up to 12-fold), 20:3n-6 (up to 25-fold) and arachidonic acid (AA; 20:4n-6) (up to 3-fold), and decreased levels of eicosapentaenoic acid (EPA; 20:5n-3) (up to 3-fold). The ratio of n-3/n-6 PUFA was decreased (up to 4-fold) and the20:4n-6/20:5n-3 ratio increased (up to 9-fold) in membrane phospholipids from fish fed SO compared to those fed fish oil. While the tissue phospholipids from fish fed La had increased levels of 18:2n-6, 20:2n-6 and 20:3n-6, the levels of AA, 22:4n-6 and 22:5n-6 were similar to or significantly reduced compared to fish fed FO. Membrane phospholipids from fish fed LO also had increased 18:3n-3 and 20:4n-3 compared to both other treatments while in some tissues and phospholipid classes EPA was increased compared to fish fed FO. 5. These dietary induced changes in phospholipid eicosanoid precursor ratio were reflected in altered eicosanoid production. In gill cells, stimulated with the calcium ionophore A23187, 12-hydroxy-8, 10, 14, 17-eicosapentaenoic acid (12-HEPE) was the major 12-lipoxygenase product in fish fed Fa. In stimulated gill cells from fish fed SO and LO, 12-HEPE, 12-hydroxy-5, 8, 10, 14-eicosatetraenoic acid (12-HETE), 14- hydroxy-4, 7, 10, 13, 16, 19-docosahexaenoic acid (14-HDHE) and thromboxane B2 (TXB2) were all decreased compared to fish fed FO. However, the ratio of 12- HETE/12-HEPE was significantly elevated in stimulated gill cells from SO-fed fish compared to both other treatments. In stimulated blood leucocytes leukotriene B4 (LTB4)' 12-HETE and TXB2 were significantly increased while LTB5 and 12-HEPE were significantly decreased in fish fed SO compared to those fed FO. Blood leucocytes from fish fed LO produced less TXB2 compared to fish fed SO and prostaglandin E2 was reduced compared to both other treatments. In isolated cardiac myocytes stimulated with A23187, TXB2 production was increased in SO fed fish compared to those fed FO. 6. The activity of cardiac sarcoplasmic reticulum Ca2+-Mg2+ATPase was not affected by dietary treatment. 7. An established cell line derived from chum salmon heart (CHH-1) was utilised to study PUFA metabolism. The CHH-1 cells exhibited considerable A6 desaturase activity but showed no preference towards n-3 over n-6 PUFA. CHH-1 cells did exhibit significant A5 desaturase activity which showed a preference towards n-3 PUFA. No A4 desaturation activity was observed. Elongation of C20 PUFA was especially active in CHH-1 cells with C22 PUFA being specifically incorporated into phosphatidylethanolamine (PE) and phosphatidylserine (PS). CHH-1 cells supplemented with 20:3n-6 showed reduced growth rate, cell death and unusual pycnotic appearance, compared to those supplemented with other PUFA. 8. The lipid compositions of hearts and livers from wild and farmed parr and presmolts were analysed and compared. The fatty acid compositions of triacylglycerols (TAG) and phospholipids from both farmed parr and pre-smolts contained greater amounts of monoenoic fatty acids compared to their wild counterparts. TAG, phosphatidylcholine (PC) and PE from heart and liver of wild fish contained more 18:2n-6 and AA compared to farmed fish. Linolenic acid, EPA and 22:Sn-3 were increased in hearts and livers of wild fish compared to farmed. Docosahexaenoic acid (DHA; 22:6n-3) levels were higher in heart and liver of farmed fish, particularly in heart PC, PS and TAG. The n-3/n-6 PUFA ratio was generally lower in wild compared to farmed fish, largely due to higher n-6 PUFA, in particular AA, in wild fish. 9. The results are discussed with respect to the competitive interactions between PUFA of the n-6 and n-3 series which determine the fatty acid compositions of membrane phospholipids in salmon. The ratio of n-3/n-6 PUFA in membrane phospholipids, and in particular the ratio of AAIEPA, appears important in terms of membrane physiology and biochemistry, eicosanoid production and the development of cardiac histopathological lesions.

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29

Kewalramani, Girish. "Amp-activated protein kinase in the heart : role in fatty acid delivery, fatty acid utilization and cell death". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/10416.

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Abstract (sommario):

Following hypoinsulinemia, glucose utilization is compromised and the myocardium switches to utilize fatty acids (FA). Previous studies have reported that PPAR-α promotes FA oxidation during chronic hypoinsulinemia. Whether the same modification also occurs in the heart during acute hypoinsulinemia and if AMP-activated protein kinase (AMPK) participates in the increase of cardiac fatty acid oxidation during this condition remains unclear. Using streptozotocin model of Type I diabetes, we report that in acute (4 days) diabetes AMPK by phosphorylating acetyl CoA carboxylase promotes cardiac fatty acid oxidation. Unexpectedly, in chronic diabetes (6 weeks), with the addition of augmented plasma and heart lipids, AMPK activation is prevented, and PPAR-α through its regulation of downstream targets controls myocardial FA oxidation. In addition to its role in FA utilization, AMPK has been implicated in controlling FA delivery through its regulation of the FA transporter, CD36. Given that LPL derived FA is the principal source of energy during insulin resistance, the question of interest was whether cardiac AMPK can regulate LPL translocation to the vascular lumen to increase the exogenous FA pool. Using dexamethasone (DEX) as an acute model of insulin resistance, my study demonstrates that, following a single dose of DEX, nongenomic phosphorylation of stress kinases such as AMPK together with insulin facilitate LPL translocation to the myocyte cell surface. Besides metabolism, AMPK has been implicated in modulating cell death. The production of tumor necrosis factor alpha (TNF-α) is reported to increase during obesity and diabetes and elevated plasma or endogenous cardiac TNF-α levels have shown to cause cardiomyocyte apoptosis. Using established AMPK activators like DEX or metformin (MET), my objective was to determine if AMPK activation prevents TNF-α-induced apoptosis in cardiomyocytes. My data demonstrates that although DEX and MET are used as anti-inflammatory agents or insulin sensitizers, their common property to phosphorylate AMPK promotes cardiomyocyte survival through its regulation of Bad and the mitochondrial apoptotic mechanism.

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30

Hantsoo, Liisa. "Fatty Acid Desaturase (FADS) Genetic Variants and Dietary Polyunsaturated Fatty Acid Intake: Associations with Negative Affect". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1333466271.

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31

Williams, Anest. "Lipid profilling of polyunsaturated fatty acid - treated mouse brain and plasma. Investigation into polyunsaturated fatty acid (PUFA)-induced neuroprotection". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4414.

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Abstract (sommario):

Pre-treatment with polyunsaturated fatty acids or bioactive lipid mediators has been shown to reduce neuronal injury in rodent models of focal ischaemia, but the molecular mechanisms underlying this neuroprotection are unclear. In this study, we aimed to investigate whether systemic administration of alpha linolenic acid (ALA) leads to changes in the profile of mouse brain phospholipid and bioactive lipid mediators in both mouse brain and plasma within the previously determined neuroprotection time window. Mass spectrometry (MS) and tandem mass spectrometry (MS/MS) allowed us to detect and identify 47 phospholipids in mouse cerebral cortex, including several phospholipid species not previously reported in brain lipidomic studies. These included a phosphatidylethanolamine species with m/z 720 that has been associated with retinal stem cells. No widespread changes in cerebral cortex phospholipid composition were observed following intravenous ALA. Several significant changes in lipid mediators (P<0.05 with two-way ANOVA and post hoc Dunnett's t test) were detected in ALA-treated animals compared to untreated and vehicle-injected animals. Many of the affected lipid mediators are ligands for prostanoid receptors which have been demonstrated to play a role in the development of brain injury following cerebral ischaemia, implying that changes in bioactive lipid mediators or modulation of prostanoid receptors may occur following ALA pre-treatment in mice. This study illustrates the potential of advanced lipidomic analysis as a novel tool for neurochemists.

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32

Brolinson, Annelie. "Regulation of Elovl and fatty acid metabolism". Doctoral thesis, Stockholm : Wenner-Gren Institute for Experimental Biology, Stockholm university : Stockholm University Library [distributör], 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8469.

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33

Baker, Genevieve Elizabeth. "Molecular insights into bacterial fatty acid metabolism". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715811.

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34

Melvin, Alison Jane. "Phospholipid fatty acid composition and insulin action". Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413198.

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35

Djian, Benjamin. "Fatty acid oxidizing enzymes in Lobosphaera incisa". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E3C2-6.

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36

Priyananda, Pramith School of Chemical Engineering &amp Industrial Chemistry UNSW. "Protein and fatty acid interactions during ultrafiltration". Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2006. http://handle.unsw.edu.au/1959.4/24310.

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Abstract (sommario):

Proteins and fatty acids often exist in solutions containing biological matter that are treated with membranes. These proteins and fatty acids interact with each other as well as with the membranes thereby affecting the flux. Binding of fatty acids to proteins results in complexes that are much larger than fatty acid molecules. Exploitation of this size difference to remove difficult to separate fatty acids from aqueous solutions by ultrafiltration was investigated in this study. In addition, the fouling of membrane by the protein-fatty acid mixtures containing free dissolved fatty acids was studied using bovine albumin (BSA)-caprylic system. Binding of caprylic acid to native and pasteurized BSA was examined by diafiltering pre equilibrated fatty acid-BSA mixtures. The rate of mass transfer of fatty acid molecules through boundary film surrounding the protein molecules was estimated using a BSA solution as the adsorbent phase in an agitated column. A stirred cell fitted with a polyethersulfone membrane (30 kDa) was used for the diafiltrations. Accumulation of fatty acid in the BSA layers fouled on the membrane was also estimated. Binding studies indicate that a native BSA molecule (at pH 6.8) could bind 7 fatty acid molecules in specific binding cavities while approximately 44 molecules are bound onto the surface. When BSA was pasteurized the specific binding decreased from 7 to 2 indicating unfolding of the molecule. In addition, the total binding capacity decreased from 44 to 24 moles/BSA mole and the rate of mass transfer decreased from 4.5/min to 3.6/min, indicating heat induced aggregation of BSA. At alkaline pH levels fatty acid anion acts as an anionic surfactant stabilizing the molecular conformation of the protein and reducing fouling. When pH was lowered to 3, flux severely declined. Unusually large accumulation of fatty acid in the deposited protein layers (caprylic/BSA ~ 10,000 moles) occurred indicating capillary condensation of undissociated fatty acids in the protein layer. Agitated column studies showed that proteins could be used as an adsorbent to remove hard to separate dissolved fatty acids from aqueous solutions. The separated protein-fatty acid complex may be further processed to manufacture animal feed.

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37

Vork, Michaël Maria. "Fatty acid-binding protein in rat heart". Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1993. http://arno.unimaas.nl/show.cgi?fid=6232.

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Abstract (sommario):

Proefschrift Maastricht.
Samenvatting in het Nederlands. Ten dele eerder verschenen en nog te verschijnen art. Auteursnaam op rug en omslag: Michaël Vork. Met lit. opg. en een samenvatting in het Nederlands.

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38

Kells, Allan Paul. "Fatty acid elongases of the mammalian testis". Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323188.

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39

Leeves, Nigel John. "Autoxidative degradation of unsaturated fatty acid esters". Thesis, Royal Holloway, University of London, 1985. http://repository.royalholloway.ac.uk/items/60dddc77-e1aa-4a11-8ee9-50abbfa8a499/1/.

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Abstract (sommario):

The autoxidative degradation of methyl cis-9-octadecenaote, methyl cis-9-cis-12-octadecadienoate and methyl cis-9-cis-12-cis-l5 octadecatrienoate promoted by both transition metal ions and photoinitiators produce volatile products. These were collected by cryogenic and chemical traps, then analysed by glc, HPLC and gc-ms. The major products so identified included; 3-heptanone, heptanal and octanal from methyl cis-9-octadecenoate, hexanal,2-hexenal and 2-heptenal from methyl cis-9-cis-12-octadecadienoate, and propanal, 1-penten-3-ol and 1-penten-3-one from methyl linolenate. Methyl octanoate was found to be a product common to the autoxidation of the three methyl esters. The major products are explained by -scissions of alkoxy radicals. The quantity of volatile compounds produced was found to depend on both the degree of unsaturation and the type of promotor. Volatile products were observed during the promoted autoxidative crosslinking of polyester resins (alkyd resins). The products so formed corresponded to the fatty acids present in the resins. Time lapse infrared spectroscopy was used to observe chemical changes occurring in the drying resin films. Hydroperoxides are the primary autoxidation products and their rate of formation was shown to depend upon the promotor used. Benzoyloxyethyl cis-9-cis-12-octadecadienoate, a model alkyd, was synthesised and autoxidised. The volatile products formed were the same as those observed from methyl cis-9-cis-12-octadecadienoate. Alkyds having a high proportion of non-esterified hydroxyl groups may be crosslinked in the presence of strong acids. This has been shown to be an autoxidative process where the hydroperoxides are decomposed by the acid to give acetal type linkages.2-Hydroxyethyl linoleate, 2-hydroxyethyllinolenate and a series of variable hydroxyl content alkyds were prepared. The volatile products isolated from the alkyds were similar to those produced using transition metal promotors but the 2-hydroxyethyl esters produced only acetal type compounds.6,9-Pentadecadiene, 8-methyl-6,9-pentadecadiene and 8,8-dimethyl-6,9-pentadecadiene were synthesised and autoxidised. The composition and quantity of 'volatile products' depended upon the degree of allylic substitution.

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40

Smith, Simon. "Polyunsaturated fatty acid oxidation in Alzheimer’s disease". Thesis, Aston University, 2011. http://publications.aston.ac.uk/16499/.

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Abstract (sommario):

Alzheimer’s disease is a neurodegenerative disorder which has been characterised with genetic (apolipoproteins), protein (ß-amyloid and tau) and lipid oxidation/metabolism alterations in its pathogenesis. In conjunction with the Dementia Research Group, Bristol University, investigation into genetic, protein and lipid oxidation in Alzheimer’s disease was conducted. A large sample cohort using the double-blind criteria, along with various clinical and chemical data sets were used to improve the statistical analysis and therefore the strength of this particular study. Bristol University completed genetic and protein analysis with lipid oxidation assays performed at Aston University. Lipid oxidation is a complex process that creates various biomarkers, from transient intermediates, to short carbon chain products and cyclic ring structures. Quantification of these products was performed on lipid extracts of donated clinical diseased and non-diseased frontal and temporal brain regions, from the Brain Bank within Frenchay Hospital. The initial unoxidised fatty acids, first transient oxidation intermediates the conjugated dienes and lipid hydroperoxides, the endpoint aldehyde biomarkers and finally the cyclic isoprostanes and neuroprostanes were determined to investigate lipid oxidation in Alzheimer’s. Antioxidant levels were also investigated to observe the effect of oxidation on the defence pathways. Assays utilised in this analysis included; fatty acid composition by GC-FID, conjugated diene levels by HPLC-UV and UV-spec, lipid hydroperoxide levels by FOX, aldehyde content by TBARs, antioxidant status by TEAC and finally isoprostane and neuroprostane quantification using a newly developed EI-MS method. This method involved the SIM of specific ions from F-ring isoprostane and neuroprostane fragmentation, which enabled EI-MS to be used for their quantification. Analyses demonstrated that there was no significant difference between control and Alzheimer samples across all the oxidation biomarkers for both brain regions. Antioxidants were the only marker that showed a clear variance; with Alzheimer samples having higher levels than the age matched controls. This unique finding is supported with the observed lower levels of lipid oxidation biomarkers in Alzheimer brain region samples. The increased antioxidant levels indicate protection against oxidation which may be a host response to counteract the oxidative pathways, but this requires further investigation. In terms of lipid oxidation, no definitive markers or target site for therapeutic intervention have been revealed. This study concludes that dietary supplementation of omega-3 fatty acids or antioxidants would most likely be ineffective against Alzheimer disease, although it may support improvement in other areas of general health.

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41

Yan, Youchun. "Enzymatic production of sugar fatty acid esters". [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9102241.

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42

Jeffries, Kristen A. "Biosynthesis of Long-chain Fatty Acid Amides". Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5850.

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The vast variety of long-chain fatty acid amides identified in biological systems is intriguing. The general structure of a fatty acid amide is R-CO-NH-X, where R is an alkyl group and X is derived from an immense variety of biogenic amines. Although structurally simple, the bioactivities of these molecules as signaling lipids are very diverse and have just recently begun to emerge in the literature. Interest in the long-chain fatty acid amides dramatically increased following the identification and characterization of one specific N-acylethanolamine, N-arachidonoylethanolamine (anandamide), as the endogenous ligand for the cannabinoid receptors in the mammalian brain. Since this discovery, the details of N-acylethanolamine metabolism have been elucidated. However, a lesser extent of progress has been made in the last twenty years to identify and study the non-N-acylethanolamine long-chain fatty acid amides. The focus of this dissertation is the elucidation of the biosynthetic pathways for long-chain fatty acid amides, including N-acylglycines, primary fatty acid amides, N-acylarylalkylamides, and N-acylethanolamines. The details of long-chain fatty acid amide metabolism will lead to the determination of possible therapeutic targets. We identified mammalian glycine N-acyltransferase like 3 as the enzyme that catalyzes the formation of long-chain N-acylglycines in mouse N18TG2 neuoblastoma cells, identified and quantified a panel of long-chain fatty acid amides in Drosophila melanogaster extracts by LC/QTOF-MS, established Drosophila melanogaster as a model system to study long-chain fatty acid amide metabolism, and identified arylalkylamine N-acyltransferase like 2 as the enzyme that catalyzes the formation of long-chain N-acylserotonins and N-acyldopamines in Drosophila melanogaster.

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43

Price, Claire Louise. "Candida CYP52 : alkane and fatty acid metabolism". Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42696.

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Cytochromes P450 are a superfamily of haem-thiolate proteins found in all kingdoms of life. To date 11294 enzymes have been identified and have been shown to be involved in the metabolism of a wide variety of substrates, including hydrocarbons and xenobiotics. In yeast and fungi the hydroxylation of alkanes is associated with a family of cytochromes P450 enzymes known as CYP52s. These enzymes are involved in the terminal hydroxylation of long-chain alkanes resulting in the production of alcohols, which can be further converted to form fatty acids and diacids. In vivo such hydrocarbons can be subjected to beta-oxidation for use in growth. Alternatively, the products formed by CYP52 catalysed hydroxylation in vitro can be used in biotechnological applications. They can be used as platform chemicals in the production of a number of industrial products, including plastics, fragrances and antibiotics. The p-oxidation of fatty acids has been less well documented for Candida albicans than for other Candida species, therefore it was the aim of this study to investigate a) did cytochromes P450 exist in C. albicans that could possibly fulfil this function and b) to definitively assign function to a single cytochrome P450. Using a bioinformatic approach, five putative CYP52s were identified in C. albicans. Of these CYP52s, Alk1 was shown to have the greatest homology to the archetypal alkane-assimilating CYP52, CYP52A3 from C. maltosa. ALK1 heterologous gene expression in the brewer's yeast Saccharomyces cerevisiae allowed growth on hexadecane (C16:0) as the sole carbon source. This showed for the first time that Alk1 is involved in the hydroxylation of long-chain alkanes as normally S. cerevisiae is unable to utilise alkanes for growth. This study has also shown that Alk1 is able to interact with sterol substrates suggesting a possible role for CYP52s in sterol metabolism, which was previously unknown.

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44

Kilaru, Aruna. "Role of Fatty Acid Ethanolamides in Plants". Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/4767.

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45

Shinde, Suhas, Shivakumar Devaiah e Aruna Kilaru. "Profiling Abscisic Acid-Induced Changes in Fatty Acid Composition in Mosses". Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/4745.

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In plants, change in lipid composition is a common response to various abiotic stresses. Lipid constituents of bryophytes are of particular interest as they differ from that of flowering plants. Unlike higher plants, mosses have high content of very long-chain polyunsaturated fatty acids. Such lipids are considered to be important for survival of nonvascular plants. Here, using abscisic acid (ABA )-induced changes in lipid composition in Physcomitrella patens as an example, a protocol for total lipid extraction and quantification by gas chromatography (GC) coupled with flame ionization detector (FID) is described.

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46

Takeuchi, Michiki. "Biochemical and applied studies on unsaturated fatty acid metabolisms in lactic acid bacteria". Kyoto University, 2015. http://hdl.handle.net/2433/199370.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第19046号
農博第2124号
新制||農||1032(附属図書館)
学位論文||H27||N4928(農学部図書室)
31997
京都大学大学院農学研究科応用生命科学専攻
(主査)教授小川順, 教授加納健司, 教授植田充美
学位規則第4条第1項該当

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47

Neijat, Mohamed. "Omega-3 fatty acid enrichment of chicken eggs: Regulation of long chain polyunsaturated fatty acid metabolism in laying hens". Poultry Science, 2014. http://hdl.handle.net/1993/32076.

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Eggs enriched with omega-3 polyunsaturated fatty acids (PUFA), particularly the longer chain PUFA (LCPUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) can boost human consumption of these fatty acids implicated in human health. Alpha-linolenic acid (ALA) from plant seeds/oils, primarily serve as the source of omega-3 PUFA for hens, however, the scarcity of ALA-rich plants and the limited conversion of ALA to LCPUFA are challenges for egg enrichment. Two major experiments were conducted to determine potential factors regulating egg enrichment of omega-3 LCPUFA based on detailed assessment of PUFA profiles in different lipid pools of hen tissues. In experiment 1, supplementation of graded levels of hempseed products, provided ~ 0.1 to 1.3% of ALA in the diets. Experiment 2, investigated dietary supplementation of flaxseed oil (ALA-rich) and algal DHA (preformed LCPUFA), each providing similar graded levels of total omega-3 PUFA. Both ALA-containing models demonstrated a plateau in DHA enrichment of eggs at higher ALA intakes. ALA-containing diets led to high concentrations of ALA in the triacylglycerol (TAG) fraction of eggs and plasma, and the adipose tissue of flaxseed oil-fed hens. In total phospholipid (PL), particularly the phosphatidylethanolamine (PE), the levels of EPA and ALA in the yolk were linearly associated with those in the liver. In all tissues, DHA dominated the PE pool, exhibiting a plateau with a strong inverse correlation to the ratio of ALA to EPA in the liver, suggesting limited ALA availability for egg DHA enrichment. The use of algal DHA should therefore permit further accumulation of DHA in the total PL and TAG fractions of yolk. However, enrichment via preformed DHA (at 3.36% algal product) was also limited by hepatic PL resulting in more DHA and EPA being shunted to the adipose TAG, concurrent with elevated hepatic acyl-CoA synthetase (ACSL1) expression. As a function of total omega-3 PUFA intakes (regardless of source), similar levels of stearidonic acid (SDA) and particularly EPA accumulated in liver PE. Therefore, hepatic PL regulation, possibly aimed at maintaining EPA level, may potentially be limiting the amount of ALA accumulation in the same pool, hence limiting the endogenous synthesis of DHA and subsequent enrichment in eggs.
February 2017

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48

Teran-Garcia, Margarita de Lourdes. "Functional mapping and characterization of the responsive region required for polyunsaturated fatty acid regulation in the rat fatty acid synthase gene". Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035987.

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49

Simoens, Christian. "Intravascular metabolism of lipid emulsions with different fatty acid pattern: influence on fatty acid profile of membrane phospholipids in target organs and cells". Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209776.

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50

Syed, Rahmatullah M. S. K. "Synthesis and physical properties of C18 azido-oxygenated and N-heterocyclic fatty acid derivatives". Thesis, [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12964657.

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Tesi sul tema "Fatty acid"

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