Siga este enlace para ver otros tipos de publicaciones sobre el tema: Fatty acids.
Tesis sobre el tema "Fatty acids"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores tesis para su investigación sobre el tema "Fatty acids".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
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.
Texto completo
2
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.
Texto completo
3
Huws, Enlli Haf. "Novel bio-active fatty acids." Thesis, Bangor University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568810.
Texto completoResumen
New methods were developed to produce thiolated analogues of Mycobacteria components. Thiolated tuberculostearic acid, (S)-18-mercapto-l O-methyloctadecanoic acid, was firstly produced in seven steps in an overall yield of 7.6 %. This was followed by the first synthesis of a thiolated simple mycolic acid, the disulfide, ((2R,2' R,3R,3' R)- 2,2' - (disulfanediylbis(tetradecane-14, I-diyl))bis(3-hydroxyhenicosanoic acid, in 11 steps in an overall yield of 2.6 %. The first synthesis of a thiolated u-rnethyl-zrcns-cyclopropane methoxy mycolic acid was also achieved using the newly developed methods with the thiol introduced at two different positions within the molecule. (S,S,S,R,S,R,2R,2R')-26-26'- Disulfanediylbis(2-((R)-I-hydroxy-19-((1 S,2R)-2-((2S, 19S,20S)-19-methoxy-20- methyloctatriacontan-2-yl)cyclopropyl)nonadecyl)hexacosanoic acid, which includes the thiolated disulfide at the end of the a-alkyl chain, was synthesised in 18 steps from synthetically prepared starting materials in an overall yield of2.6 %. (S)-2-((S)-I-Hydroxy- 19-((1R,2S)-2-((2R, 19R,20R)-19-methoxy-20-methyloctatriacontan-2- yl)cyclopropyl)nonadecyl)-N-(2-((2-((R)-2-((R)-I-hydroxy-19-((IS,2R)-2-((2S, 19S,20S)- 19-methoxy- 20-methyloctatria-contan- 2- yl)cyclopropyl)nonadecyl)hexacosanamido )ethyl)disulfanyl)ethyl)hexacosan-amide, which contais a thiolated linker on the carboxylic acid, was synthesised in two steps from the free synthetic mycolic acid in an overall yield of 8.7 %. The different methods attempted for the formation of the thiolated analogues are discussed. To attempt to maximise the inhibitory effect of sterculic acid against Plasmodium falciparum /19 desaturase, which is essential for parasite growth, analogues of sterculic acid were designed and synthesised. 7-(2-0ctyl-cycloprop-l-enyl)-heptanoic acid methyl ester and 9-(2-octyl-cycloprop-l-enyl)-nonanoic acid methyl ester which contain one more and one less carbon atoms than sterculic acid in their chain lengths respectively were both synthesised in five steps in overall yields of 8 % and 4.6 % respectively. (±)-8-Methoxy-8- (2-octyl-cycloprop-l-enyl)-octanoic acid methyl ester was subsequently synthesised in three steps in an overall yield of 36 % whilst (±)-8-hydroxy-8-(2-octyl-cycloprop-l-enyl)- octanoic acid methyl ester was also synthesised in three steps in an overall yield of 25 %. In four steps both (± )-8-(tert-butyldimethylsilyloxy)-8-(2-octyl-cycloprop-l-enyl)-octanoic iii acid methyl ester and (±)-8-acetoxy-8-(2-octyl-cycloprop-I-enyl)-octanoic acid methyl ester were synthesised in an overall yield of 22.7 % and 34.9 % respectively. The inhibitory effects of these analogues were investigated.
4
Pararasa, Chathyan. "Fatty acids, monocytes and ageing." Thesis, Aston University, 2013. http://publications.aston.ac.uk/20894/.
Texto completoResumen
Elevated free fatty acids (FFA) are a feature of ageing and a risk factor for metabolic disorders such as cardiovascular disease (CVD) and type-2 diabetes (T2D). Elevated FFA contribute to insulin resistance, production of inflammatory cytokines and expression of adhesion molecules on immune cells and endothelial cells, risk factors for CVD and T2D. Molecular mechanisms of FFA effects on monocyte function and how FFA phenotype is affected by healthy ageing remain poorly understood. This thesis evaluated the effects of the two major FFA in plasma, oleate and palmitate on monocyte viability, cell surface antigen expression, and inflammatory activation in THP-1 monocytes. Palmitate but not oleate increased cell surface expression of CD11b and CD36 after 24h, independent of mitochondrial superoxide, but dependent on de novo synthesis of ceramides. LPS-mediated cytokine production in THP-1 monocytes was enhanced and decreased following incubation with palmitate and oleate respectively. In a model of monocyte-macrophage differentiation, palmitate induced a pro-inflammatory macrophage phenotype which required de novo ceramide synthesis, whilst oleate reduced cytokine secretion, producing a macrophage with enhanced clearance apoptotic cells. Plasma fatty acid analysis in young and mid-life populations revealed age-related increases in both the SFA and MUFA classes, especially the medium and very long chain C14 and C24 fatty acids, which were accompanied by increases in the estimated activities of desaturase enzymes. Changes were independently correlated with increased PBMC CD11b, plasma TNF-a and insulin resistance. In conclusion, the pro-atherogenic phenotype, enhanced LPS responses in monocytes, and pro-inflammatory macrophage in the presence of palmitate but not oleate is reliant upon de novo ceramide synthesis. Age-related increases in inflammation, cell surface integrin expression are related to increases in both the MUFA and SFA fatty acids, which in part may be explained by altered de novo fatty acid synthesis.
5
Kishino, Shigenobu. "Production of conjugated fatty acids by lactic acid bacteria." Kyoto University, 2005. http://hdl.handle.net/2433/86244.
Texto completoResumen
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第11617号<br>農博第1473号<br>新制||農||905(附属図書館)<br>学位論文||H17||N4010(農学部図書室)<br>UT51-2005-D366<br>京都大学大学院農学研究科応用生命科学専攻<br>(主査)教授 清水 昌, 教授 加藤 暢夫, 教授 植田 充美<br>学位規則第4条第1項該当
6
Kew, Samantha. "Fatty acids and the immune system : dose response studies with n-3 polyunsaturated fatty acids." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396188.
Texto completo
7
Yu, Rong. "Metabolic interactions among amino acids, phospholipids and fatty acids." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45211.
Texto completoResumen
Cystic fibrosis (CF) is the most common life-shortening disorder among Caucasians. Excessive faecal bile acid loss, increased oxidant stress, reduced plasma choline, increased oxidant stress, reduced glutathione and alterations in essential fatty acids are well recognized in patients with CF. It is also well-known that diabetes perturbs the methionine-homocysteine cycle. However, experimental data linking loss of amino acids in CF or decreased glucose availability in experimental diabetes to altered phospholipids and fatty acid metabolism are lacking. In the liver, bile acids are conjugated with glycine or taurine prior to secretion, and glycine de novo synthesis begins with glucose. Thus, the objectives of this thesis are: 1) to determine if inducing faecal bile acid loss will alter the methionine-homocysteine, and choline-betaine cycle metabolites, phospholipids and phospholipids n-6 and n-3 fatty acids, and 2) to show that experimental diabetes, which decreases glucose availability, alters methionine-homocysteine and choline-betaine cycle metabolites, phospholipids and phospholipid fatty acids in rats.
Studies to address the first objective demonstrated that inducing faecal bile acid malabsorption leads to fat malabsorption with increased faecal total lipids and phospholipid excretion. This increased excretion was accompanied by increased plasma betaine concentration, decreased plasma triacylglycerol concentration, increased plasma and liver S-adenosylhomocysteine (SAH) concentration, and changes in the fatty acid composition of hepatic phospholipids. Studies to address the second objective showed that experimental diabetes led to increased plasma betaine concentration, decreased homocysteine concentration, increased liver phosphatidylethanolamine, decreased phosphatidylcholine, changes in the fatty acid composition of hepatic phospholipids, and abundance of the enzyme choline dehydrogenase. Thus, experimental diabetes, which reduces intracellular glucose availability, alters methionine-homocysteine and choline-betaine cycle metabolites, phospholipids and fatty acids. In conclusion, metabolism of phospholipids, their fatty acids, and the amino acids involved in the methionine-homocysteine cycle are inter-related.
8
Peet, Daniel J. "Protein-bound fatty acids in mammalian hair fibres /." Connect to thesis, 1994. http://eprints.unimelb.edu.au/archive/00000641.
Texto completo
9
Sieberg, Maureen A. "Heritability and development of the free fatty acids and acylglycerideconstituent fatty acids in Vernonia galamensis oil." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280501.
Texto completoResumen
Since the mid-1970's, there has been active research on the development of Vernonia galamensis (Cass.) Less. as a potential new oilseed crop. Vernolic acid (cis-12:13-epoxy-cis-9-octadecenoic acid) comprises 70--75% of vernonia oil and is chemically reactive, affording it a variety of industrial applications. A concern in the domestication of an oilseed crop is to establish a breeding program to improve oil quality traits. The objectives of this research were to (1) develop a rapid procedure for seed analyses; (2) determine the development of vernonia oil; and (3) estimate the narrow-sense heritability (h 2) of oil quality traits. Successful separation of free fatty acids (FFA) and acylglycerides from small vernonia seed samples was achieved using aminopropyl solid phase extraction columns. Acylglycerides were eluted with a mixture of chloroform and isopropanol, while FFA were eluted with a mixture of acetone and trifluoroacetic acid. Four breeding lines from a collection of Vernonia galamensis held at the US Water Conservation Laboratory in Phoenix, AZ were used for the oil development study and grown in field trails in Phoenix and Tucson, Arizona. Seeds were collected on nine different days after flowering over the course of seed maturation. Seed samples were analyzed for FFA, acylglyceride constituent fatty acids, total acylglycerides, and total oil. In each breeding line, FFA content changed significantly throughout the course of the measurement period, and synthesis of acylglycerides constituent fatty acids followed a previously described pathway proceeding from C16:0 to C18:0 to C18:1 to C18:2 to C18:1 epoxy. Vernolic acid increased late in the measurement period, while total acylglycerides and total oil increased steadily over the period. Mature vernonia seed exhibited substantial variation in the amount of FFA, acylglyceride constituent fatty acids, total acylglycerides, and total oil. Sixty-nine half-sib families were created to study the heritability of FFA, vernolic acid, acylglycerides, and total oil production. Mature capitula were collected and analyzed individually for oil constituents. Narrow sense heritability estimates for these four oil quality traits were: FFA = 33%, vernolic acid = 65%, acylglycerides = 47%, and total oil = 50%. The results indicate potential for progress in selection for these traits.
10
Barton, Louise Marie. "Polyunsaturated fatty acids and adrenal steroidogenesis." Thesis, Royal Veterinary College (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.519549.
Texto completo
11
Zhang, Runhou 1963. "Manipulating fatty acids in sheep milk." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102236.
Texto completoResumen
Four studies were conducted to investigate some factors affecting milk fatty acid composition of dairy ewes. The first study was performed to determine the influence of freezing temperatures and storage time on ovine milk composition and cheese making. The other three experiments were conducted to examine the effects of dietary added fats with different profiles of fatty acids from canola, sunflower and flaxseeds on animal performance, nutrient utilization, milk yield and cheese making. The main emphasis was on fatty acid composition, particularly CLA and Omega-3 fatty acids, in milk and cheese. Results showed that: (1) feeding up to 8% of canola, sunflower and flaxseed had no adverse effects on dry matter intake and total tract digestibilities of dry matter, neutral detergent fiber, acid detergent fiber and crude protein, while the digestibilities of fatty acids and gross energy were increased with oilseed supplementation; (2) feeding flaxseed to lactating ewes up to 260g/ewe/d increased milk yield by up to 8.4%, and fat content by up to 14.3% without adversely affecting other milk components or cheese yield and composition; (3) Oilseed supplementation increased milk concentrations of long-chain and unsaturated fatty acids in the expenses of short-chain, medium-chain and saturated fatty acids. The concentrations of CLA and Omega-3 fatty acids were also increased by oilseed supplementation; (4) the manipulated fatty acids profiles can be reflected in cheese; (5) good quality cheese can be produced from ovine milk frozen at -15°C and -25°C for up to 6 months without influencing cheese content of fat and protein and fatty acid composition.<br>In conclusion, ovine milk with nutritionally healthy characteristics can be produced by feeding ewes diets with oilseeds, and freezing storage of milk for up to 6 months at -15°C or -25°C does not significantly affects milk composition including fatty acid composition. The characteristics of milk can be reflected in cheese.
12
Beysen, Carine. "Metabolic effects of specific fatty acids." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249513.
Texto completo
13
Rogerson, Madeleine. "Interactions of phospholipids with fatty acids." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398493.
Texto completo
14
Glen, Anthony D. "Synthetic studies on cyclopropane fatty acids." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386040.
Texto completo
15
Peacock, Lesley. "Isomeric fatty acids and platelet function." Thesis, University of Aberdeen, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253708.
Texto completoResumen
1. <i>Cis</i> unsaturated fatty acids were shown to inhibit porcine platelet aggregation in response to both collagen and thrombin. Fatty acids with a <i>trans</i> double bond had an anti-aggregatory effect on collagen-induced aggregation but this was significantly less than that observed with the <i>cis</i> equivalent and was diminished as the dose of agonist increased. Thrombin-induced platelet aggregation was unchanged or slightly potentiated by <i>trans</i> isomers. 2. Both the <i>cis</i> and <i>trans</i> isomeric acids inhibited collagen-induced TXB<sub>2</sub> production. The <i>trans</i> unsaturated fatty acids also inhibited TXB<sub>2</sub> production in response to thrombin, even though they did not inhibit thrombin induced platelet aggregation. 3. Unlike arachidonic acid, the <i>cis</i> and <i>trans</i> mono-unsaturated fatty acids were not rapidly incorporated into membrane phospholipids but modified platelet aggregation whilst in the free acid form. 4. Pre-incubation of platelets with either <i>cis</i> or <i>trans</i> delta 13, 18:1, selectivity inhibited the incorporation of radio-labelled arachidonic acid into membrane PS. 5. <i>Cis</i> and <i>trans</i> unsaturated delta 13, 18:1, inhibited the initial turnover of membrane PI in response to thrombin possibly by an inhibitory effect on PI-specific phospholipase C. After 5 minutes, however, the level of arachidonic acid released from both PI and PE was increased in the presence of the isomeric fatty acids. This may have been via a potentiation of the action of phospholipase A<sub>2</sub>. 6. An increased release of arachidonic acid could result in the inhibition of aggregation if metabolised via the 12-lipoxygenase pathway, as the end products of this sytem have direct anti-aggregatory activity and inhibit the cyclo-oxygenase enzymes thus reducing TXA<sub>2</sub> synthesis. 7. <i>Cis</i> unsaturated fatty acids, which produce a greater level of membrane disruption than the <i>trans</i>, may lead to more efficient channelling of the released arachidonic acid in the direction of the lipoxygenase pathway, and thereby produce a greater inhibition of aggregation. The possibility remains that the <i>cis</i> isomers have another, as yet unidentified mechanism by which they inhibit platelet aggregation.
16
Bonner, Shelagh Anne. "Immunomodulatory effects of dietary fatty acids." Thesis, University of Strathclyde, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366809.
Texto completo
17
Wilson, Gillian Mary. "Fatty acids in human colonic mucosa." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316584.
Texto completo
18
O'Keeffe, Majella. "New sources of polyunsaturated fatty acids." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54727/.
Texto completoResumen
Two groups of essential fatty acids (n-6 and n-3) are needed in a healthy human diet. Current advice suggests an optimal ratio of about 4:1 for these polyunsaturated fatty acids (PUFAs) in the diet but in Western countries it is usually 10-20:1. The n-3 PUFAs are synthesized in photosynthetic organisms from where they move up the food chain. Fish in particular, are a rich source of twenty and twenty two carbon n-3 PUFAs which are particularly effective for humans. Fish oils have been shown to be beneficial in a variety of chronic inflammatory diseases. However, fish stocks arc under threat. Therefore, fish farming has increased recently and offers some opportunities for viable sources of n-3 PUFAs, especially since disposal of fish farm waste is expensive and environmentally problematic. In this project, we investigated trout (<italic> Oncorhynchus mykiss</italic>) as a potential source of n-3 PUFAs. The lipid composition of different tissues was analysed by combinations of TLC and GLC. This work identified the differences between various individual tissues and pin-pointed those with high eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) content. Two possible industrial lipid extraction methods were compared with a standard laboratory procedure. These studies included a comparison of yields for offal which had been stored for various times. The rendering method, although not as efficient as the laboratory procedure (Garbus), was concluded to allow oil yield for nutraceutical development although tissues could not be stored for greater than two days without compromised quality. Finally, oil extracts from trout (containing 2.5% EPA and 10.5% DHA) were tested in a model system (bovine cartilage explants) as treatment for osteoarthritis. The trout oil preparation significantly reduced cytokine-induced glycosaminoglycan release indicating a protective action. However, it was not as effective as pure EPA or DHA. Moreover, the trout oil preparation was not able to reduce mRNA levels of inflammatory genes (e.g., COX-2, IL-6, ADAMTS-4, -5 and MMP-3) which were lowered by pure EPA or DHA supplementation. We conclude that trout waste is a viable source of n-3 PUFAs for nutraceutical development but that processing will probably be needed to produce a dietary supplement with potent anti inflammatory properties.
19
Smith, Benjamin. "Mineral mediated catalysis of fatty acids." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10611/.
Texto completoResumen
In order to reduce reliance on fossil oil, and it’s associated problems, there is a need to develop new platform chemicals, fuels and products, in a sustainable way, from biomass. In this thesis the catalytic upgrading of fatty acids, derived from the lipid fraction of biomass, through deoxygenation reactions is studied. Chapter 1 reviews the general area of catalytic upgrading of biomass into biofuels and bioproducts. The history and motivation for alternative sources of fuels and materials are introduced, followed by a summary of the reaction processes currently utilised for biofuels and bioproducts production. It is shown that the demand for alternative fuel sources initially led to the mass commercial production of ethanol, via fermentation of sugars, and biodiesel, through trans-esterification of lipids present in vegetable and algal oils. A selection of the catalysts and mechanisms for trans-esterification reactions is reviewed and, following an outline of the fuel properties and processes, an evaluation of “green diesel” production is given, whereby fatty acids are converted directly into hydrocarbons through decarboxylation reactions. This review culminates in an analysis of alternative conversion of fatty acids into long chain ketone bioproducts, namely ketonic decarboxylation, which details the catalysts and processes involved to date. Chapter 2 describes the analytical methods utilised in this thesis to investigate heterogeneous catalysis of biomass conversion, along with the relevant background theory and describes the type of data that can be obtained using the techniques. The techniques include powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, inductively coupled plasma optical emission spectroscopy, surface area analysis, Hammett basicity, elemental analysis, Fourier-transform infra-red spectroscopy and gas chromatography. Chapter 3 introduces a class of materials known as layered double hydroxides (LDHs) of general formula Mz+1–xM3+x (OH)2]q+(Xn–)q/n•yH2O. The ease with which these mixed oxide materials may be prepared offers significant scope for the variation of the metal cations; the M2+:M3+ ratio (denoted R-value); the counter anion(s); and crystal morphology. These LDHs consist of positively charged layers, with negatively charged counter-anions and water residing in the interlayer. A review of the commonly used synthesis methods for LDHs is given, along with the advantages and disadvantages associated with each method. Following this, the synthesis of the Mg-Al LDHs and their calcined counterparts, mixed metal oxides (MMOs) (for R-values 1-6) via a readily scalable co-precipitation (CoP) and a more environmentally-friendly co-hydration (CoH) route is described. A range of techniques, outlined in chapter 2, are utilised to study the LDH and MMO crystal and chemical structures, surface topography, surface area, pore volume and relative basicities. The crystal structures of two of the CoP-LDHs were refined to the 3R-polytype using DICVOL, however the other LDHs were not significantly ordered and could not be refined. Upon calcination from LDHs to MMOs, the interlayer counter-anions and water are lost, along with the layered structure, leading to a commensurate increase in surface area and pore volume. In chapter 4, investigations undertaken to deoxygenate stearic acid, a free fatty acid model biomass compound, are described. As a catalyst, 5 % Pd/C was used, adapting a method found in the literature. These reactions were undertaken at 230 °C, with decarboxylation of stearic acid producing straight-chain n-heptadecane at up to 58 % conversion by gas chromatography analysis. However, in this study, issues arose due to catalyst instability and an ensuing loss of catalyst activity was observed. In chapters 5 and 6, to increase catalyst stability and recyclability, while also reducing costs relative to the Pd/C catalyst used in chapter 4, (due to the use of precious metals), LDHs and their calcined derivatives, MMOs, were utilised for deoxygenation of the model stearic acid biomass. Thermal reactions of stearic acid controls, without catalyst, were not observed to occur, however, stearic acid conversions between 83-97 % at 250 °C were observed to occur with both LDH and MMO catalysts. However, unlike the Pd/C reaction, no decarboxylated product was evidenced and, instead, a waxy solid formed, which was subsequently analysed and found to be the ketonic decarboxylation product, stearone. A protocol was developed to separate the stearone from the catalyst. Gas chromatography analysis showed the LDH and MMO materials catalysed the conversion of stearic acid to a similar degree, allowing for the error within the extraction and analysis processes employed. The reasons for similarity in reactivity are discussed, and it is suggested that an intermediate state of catalyst is present in the reactor. Comparing synthesis methods, the CoH materials were as effective as their CoP counterparts, despite the presence of Mg(OH)2 secondary-phases. Within the LDH phases, an indication of catalytic dependence on pore size was also recorded, with the smaller pore-sized materials leading to lower conversions of stearic acid, resulting from the bulky size and required head alignment of the long-chain fatty acid molecules. In terms of control reactions, calcined MgO led to 90 % conversion of stearic acid to stearone, however very little reaction occurred with uncalcined MgO (0.5 %) and zero reaction with the acidic Al2O3 (both uncalcined and calcined). Hence activated MgO is also an effective catalyst for ketonic decarboxylation. Chapter 7 summarises the results and discussion given within this thesis, highlighting the milestones achieved such as the first ketonic decarboxylation reactions involving MMO catalysts and concluding that LDHs and MMOs catalyse the conversion of stearic acid via ketonic decarboxylation of free fatty acids to high value ketones, to a similar degree, within the associated errors. In addition the LDH synthesis method employed does not play a significant role in the degree of catalysis, resulting in the recommendation that the more environmentally-friendly co-hydration synthesis method should be employed for the catalyst involved in the conversion of stearic acid derived from biomass. The MMO catalysts were found to behave akin to the calcined MgO material during the ketonic decarboxylation of stearic acid, while the catalytic reactions involving LDH catalysts were potentially involving the interaction of their interlayer anions and cations. Finally, a summary of additional work for further developing this process is discussed.
20
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.
Texto completoResumen
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.<br>October 2015
21
Bradburn, David Michael. "Bile acids and short fatty acids in familial adenomatous polyposis." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308760.
Texto completo
22
Qadir, Abdul. "The effects of endotoxaemia and omega-3 fatty acids on membrane fatty acids and cardiac G-proteins." Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300911.
Texto completoResumen
Dietary manipulation was undertaken with the aim of influencing membrane composition and improving adrenergic dysfunction. The objective was to explore the effects of 5 days of continuous intra-duodenal feeding of diets containing n-3 PUFA on myocyte membrane phospholipids, contractility and G-protein. The control diet was omega-6 (n-6) PUFA from safflower oil. The animals were infused with either saline or endotoxin (1 mg/kg) in the last 24 hours. The diets resulted in incorporation of lipids with alteration in myocyte membrane lipid composition. The relative percentage of n-3 PUFA was increased in the fish oil group (22.61± 1.30, 20.46±1.35 for control and endotoxin) compared to safflower oil group (15.21±1.77, 14.16±0.56 for control and endotoxin). The mean inotropic response to isoprenaline was improved by feeding of n-3 PUFA enriched diets (0.175±0.027 for safflower oil endotoxin group vs 0.264±0.03 for safflower oil control, 0.261±0.064 for fish oil control and 0.275±0.073 for fish oil endotoxin group). The adenylyl cyclase activity on forskolin stimulation was not affected by diet or endotoxin (0.165±0.036, 0.176±0.058 for safflower control and endotoxin, and 0.163±0.036, 0.173±0.017 for fish oil control and endotoxin). The data on forskolin stimulation suggested distal contractile mechanisms were intact and that the defect in βAR signal was occurring at a site proximal to adenylyl cyclase. Sodium fluoride, a direct activator of G-proteins revealed a much greater degree of stimulation in the fish oil endotoxin group compared to the safflower oil endotoxin group (0.013±0.030 for safflower oil endotoxin, 0.053±0.015 for fish oil endotoxin and 0.055±0.022 for safflower oil control, 0.088±0.26 for fish oil control). The mean relative percentage of Gαo subunits was reduced in fish oil endotoxin group compared to safflower oil endotoxin group (16.65±3.01 for fish oil endotoxin, 25.37±1.29 for safflower oil endotoxin and 15.63±0.91 for safflower oil control, 13.06±2.70 for fish oil control). In summary, n-3 PUFA improve βAR transmembrane signal in endotoxaemia by favourably altering G-regulatory proteins possibly through membrane displacement of n-6 fatty acids.
23
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.
Texto completo
24
Bakare, Oladapo. "Synthesis and properties of sulphur-containing long chain fatty acid derivatives." Thesis, [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13544561.
Texto completo
25
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.
Texto completoResumen
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.
26
Maisonet, Mildred, Ruby Yadav, and 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.
Texto completoResumen
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).
27
Scorletti, Eleonora. "Effect of omega-3 fatty acids in non-alcoholic fatty liver disease." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/422265/.
Texto completoResumen
The first chapter (Introduction) of the thesis summarises the pathogenesis of NAFLD and its associated risk factors such as type 2 diabetes and cardiovascular disease. Moreover, it describes: a) the potential beneficial effects of long chain omega-3 fatty acid treatment [docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA)] in NAFLD; b) the effect of genotypes patatin-like phospholipase domain-containing protein-3 (PNPLA3 I148M) and the transmembrane 6 superfamily member 2 protein (TM6SF2 E167K), on the level of DHA and EPA enrichment and end of study liver fat percentage after DHA+EPA treatment; and c) the effect of fatty acid desaturase (FADS) and Elongase (ELOVL) polymorphisms influencing omega-3 fatty acid metabolism. The second chapter describes the overall aim of this thesis. The aim of my research was to investigate in patients with NAFLD: a) the effect of long-chain omega-3 fatty acid treatment on liver fat percentage and liver fibrosis biomarkers; b) the effect of genotypes influencing NAFLD severity on treatment with DHA+EPA; and c) the effect of genotypes influencing omega-3 fatty acid metabolism in NAFLD. The third chapter describes in details the design and methods used in my research. Chapter four highlights my novel results from the WELCOME study. This chapter describes the baseline and end of study characteristics of the WELCOME study participants and shows the results of the DHA+EPA treatment on liver fat percentage and liver fibrosis biomarkers. This chapter also describes the association between DHA erythrocyte enrichment and decrease in liver fat percentage after DHA+EPA treatment. Chapter five illustrates the association between PNPLA3 I148M and DHA erythrocyte enrichment percentage and end of study liver fat percentage after DHA+EPA treatment. The chapter shows that PNPLA3 I148M was associated with higher end of study liver fat percentage and lower DHA tissue enrichment. Chapter six shows the negative association between FADS polymorphisms and omega-3 fatty acid metabolism in NAFLD. The chapter also shows that there was a gene-DHA+EPA interaction between the minor allele of the FADS1 rs174556 and Δ-5 desaturase activity after treatment with DHA+EPA. Finally, chapter seven, summarises my results in the context of current evidence and knowledge about the subject matter.
28
Akpinar, Arzu. "Transformations of fatty acids in filamentous fungi." Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363270.
Texto completo
29
Pinto, Eva. "Polyunsaturated fatty acids and immune cell functions." Thesis, University of Greenwich, 2007. http://gala.gre.ac.uk/6268/.
Texto completoResumen
In MS patients there was a significantly positive relationship between membrane AA and TGF-ß1 indicating that it is the individual long chain (LC) PUFA, i.e. AA that regulate the levels of TGF-ß1. Investigation of the effects of n-6 and n-3 PUFAs on normal healthy PBMC production of TGF-ß1 in vitro showed that PBMC in the presence of phytohaemaglutinin (PHA) supplemented with LA, dihyomo-?-linolenic (DGLA) and arachidonic acid (AA) significantly increase TGF-ß1 compared with non-supplemented PHA-stimulated PBMCs. In contrast, TGF-ß1 levels from PHA-stimulated PBMCs supplemented with a-linolenic (ALA), eicosapentaenoic (EPA) or docosahexaenoic acid (DHA) were significantly decreased suggesting that n-6 fatty acids (LA, DGLA and AA) increase in vitro TGF-ß1 production by PHA-stimulated PBMCs and, in contrast, n-3 fatty acids (ALA, EPA and DHA) decrease TGF-ß1 production. GLA-rich borage oil supplementation resulted in significantly decreased ex vivo monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1a (MIP-1a) and interleukin-8 (IL-8) production from PHA-or LPS-stimulated PBMC compared with baseline. It also significantly decreased cell surface expression of CD36+, CD54+ and CD62L+ on monocytes. In contrast, there was no association between LA-rich corn oil and these adhesion molecules and chemokines suggesting that GLA and/or its metabolites are affecting the chemokines and adhesion molecules studied. Overall, results of this study indicate that n-6 long chain PUFAs may have anti-inflammatory properties and might therefore be beneficial in multiple sclerosis, atherosclerosis and other inflammatory diseases.
30
Abouzreba, Salem Ali. "Volatile fatty acids in the ambient atmosphere." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388115.
Texto completo
31
Hartil, Kirsten. "Fatty acids, insulin sensitivity and skeletal muscle." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621348.
Texto completo
32
Lalia, Antigoni. "Omega-3 fatty acids to combat sarcopenia." Thesis, College of Medicine - Mayo Clinic, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10124986.
Texto completoResumen
<p> <b>Background:</b> Age-related sarcopenia leads to frailty, physical disability and loss of independence. Although exercise is an effective strategy to counteract the prevailing loss of muscle mass, older adults exhibit blunted anabolic responses, and are often unable to adopt an active lifestyle due to comorbidities associated with aging. Long chain polyunsaturated fatty acids (n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, are non-pharmaceutical nutrients which have surfaced for their potential anabolic properties on skeletal muscle and may be particularly beneficial in the context of sarcopenia. </p><p> <b>Objective:</b> First, to determine if EPA and DHA increase muscle protein synthesis in older adults. Second, to determine if n-3 PUFA increase the anabolic response to an acute resistance exercise stimulus in older adults. Third, to assess if their effect is mediated through improved mitochondrial function, which is known to be impaired with aging. </p><p> <b>Methods:</b> Twelve old, sedentary, healthy women and men (65-85 years) were given 3.9 grams/day purified EPA/DHA for 4 months. 12 young adults (18-35 years) were included as a comparison group for baseline measurements. Muscle protein fractional synthesis rate (FSR) was measured before and after treatment for mixed muscle, and subcellular fractions of myofibrillar, mitochondrial and sarcoplasmic proteins. We infused a stable isotope tracer of [ring-<sup> 13</sup>C<sub>6</sub>] phenylalanine and monitored incorporation of the amino acid into muscle proteins, at the fasting, post absorptive state, and 16 hours following an acute bout of unaccustomed resistance exercise, using mass spectrometry. Muscle mitochondrial function was assessed <i>ex vivo </i> from skeletal muscle biopsies. Further mechanistic information was generated through large scale and individual mRNA gene expression, inflammatory markers, and protein phosphorylation signaling of the anabolic pathway. </p><p> <b>Results:</b> Protein synthesis was similar between age groups at baseline and post exercise, despite the robust decline in mRNA gene expression with aging. EPA/DHA supplementation increased total lean mass, and increased mitochondrial and sarcoplasmic FSR at baseline. Following acute exercise, mixed muscle and subcellular FSR did not change significantly, but participants were segregated into responders and non-responders. EPA/DHA further potentiated the anabolic response of mitochondrial FSR to levels greater than that in the young. There was no improvement in mitochondrial oxidative capacity and efficiency, but there was a significant decrease in ROS emissions. </p><p> <b>Conclusion:</b> In healthy older adults, EPA/DHA exhibited significant anabolic effect in baseline skeletal muscle mitochondrial and sarcoplasmic FSR, which was dissociated from mitochondrial oxidative capacity. The anabolic response to exercise was variable between responders and non-responders where some individuals presented with marked increase in mixed muscle and subcellular FSR. This observation sets the ground for identifying the phenotypic traits of the elderly who are likely to benefit from the therapeutic use of n-3 PUFA to combat sarcopenia of aging.</p>
33
O'Shea, Karen Michelle. "Omega-3 Fatty Acids and Heart Failure." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1258128805.
Texto completo
34
Wu, Zhiguo. "Ruminal synthesis and biohydrogenation of fatty acids /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683756125827.
Texto completo
35
Afonso, Marise da Costa Pereira. "Enzymatic biodiesel production from free fatty acids." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/3137.
Texto completoResumen
Mestrado em Materiais Derivados de Recursos Renováveis<br>O ácido oleico é um co-produto da refinação de óleos alimentares e é removido num passo antecedente à catalise alcalina na produção industrial de biodiesel. Este ácido gordo livre é uma fonte alternativa de biodiesel.
Neste trabalho estudou-se a esterificação enzimática do acido oleico com metanol ou etanol. Definiu-se um planeamento experimental 22 para estudar a influência das variáveis razão molar álcool/ácido oleico(R) e concentração de enzima(E), as variáveis dependentes, na percentagem de conversão, a variável independente. As condições óptimas foram obtidas em R=6,32 e E=6,64% para o metanol (100% conversão), e R=4,87 e E=5,65 % para o etanol (95,5% de conversão).
Estudou-se também a influência da temperatura na reacção para uma razão molar de 6 e uma concentração de enzima de 2%, numa gama de temperaturas entre 30 e 60ºC, para o metanol, e 70ºC, para o etanol. Foi constatado que a conversão aumenta monotonamente com o aumento da temperatura para o etanol. Para o metanol, o aumento da conversão com o aumento da temperatura apenas se verifica até aos 50ºC. A mesma enzima pode ser usada 10 vezes na esterificação enzimática do ácido oleico com etanol, sem perda significativa de actividade enzimática.
ABSTRACT: Oleic acid is a co-product of oil refining and is removed in a step preceding the alkaline catalysis in industrial production of biodiesel. This free fatty acid is an alternative source of biodiesel. In this present work the enzymatic esterification of oleic acid with methanol or ethanol was studied. Was defined as an design of experiments 22 to study the influence of the alcohol / oleic acid molar ratio (R) and enzyme concentration (E), the dependent variables, in the percentage of conversion, the independent variable The optimal conditions obtained were R=6.32 and E=6.64% for methanol (100% conversion), and R=4.87 and E=5.65% for ethanol (95,5% of conversion. Was also studied the influence of temperature on the reaction to a molar ratio of 6 and an enzyme concentration of 2%, in a temperature range between 30 and 60 ° C for methanol, and 70 ° C for ethanol. It was found that the conversion increases monotonously with increasing temperature for ethanol. For methanol, the conversion increased with increasing temperature up to 50 º C. The same enzyme can be used 10 times in the enzymatic esterification of oleic acid with ethanol, without significant loss of enzyme activity.
36
Hudson, Elizabeth A. "Polyunsaturated fatty acids in tumour-induced cachexia." Thesis, Aston University, 1993. http://publications.aston.ac.uk/12600/.
Texto completoResumen
A transplantable murine colon adenocarcinoma (MAC16) was utilised as a model of human cancer cachexia. This tumour has been found to produce extensive weight loss, characterised by depletion of host body protein and lipid stores at a small tumour burden. This weight loss has been found to be associated with production by the tumour of a lipolytic factor, activity of which was inhibited in vitro by the polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (EPA). EPA has also been shown to possess anti-tumour and anti-cachectic activity in vivo, leading to the hypothesis that fatty acids mobilised by the lipolytic factor supply a growth requirement of the MAC16 tumour. In this study mobilisation and sequestration of fatty acids by the tumour was found to be non-specific, although a relationship between weight loss and arachidonic acid (AA) concentration was found in both tumour-bearing mice, and human cancer patients. The anti-tumour effect of EPA, which was found to be associated with an increase in cell loss, but not its anti-cachectic activity, was reversed by the administration of the PUFAs oleic acid (OA) and linoleic acid (LA). LA was also found to be capable of stimulating tumour growth. Inhibition of either the cyclooxygenase or lipoxygenase pathways was found to result in reduction of tumour growth, leading to the implication of one of the metabolites of LA or AA in tumour growth and cachexia. The ethyl ester of EPA was found to be inactive against the growth and cachexia of the MAC16 tumour, due to its retarded uptake compared with the free acid. The anti-proliferative agent 5-fluorouracil was found to cause tumour growth inhibition, and when given in combination with EPA, reduced the phase of tumour regrowth observed after 4 to 5 days of treatment with EPA.
37
Wang, Qianyi. "Fatty Acids, Cardiovascular Diseases, and Diabetes Mellitus." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:14117764.
Texto completoResumen
Cardiovascular disease (CVD) is the number one cause for mortality and morbidity around the world. Meanwhile, diabetes mellitus (DM) has become an emerging epidemic, causing 1.5 million deaths in 2012, with 80% occurring in low- and middle-income countries. Substantial evidence has linked both lifestyle and metabolic risk factors to increased risk of CVD and death, with suboptimal diet being the single leading modifiable cause of poor health (Lim. SS, et al, Lancet 2012). Of 20 top individual causes of disease burden worldwide, 8 are related to poor nutrition, including suboptimal intakes of various dietary fatty acids. Although previous studies have found divergent health effects of different dietary fatty acids on health, gaps still exist in terms of the scientific knowledge (e.g. how individual circulating vs. dietary trans fatty acid subtypes affect health) and related disease burdens (e.g. national CHD mortality burdens attributable to suboptimal intakes of fatty acids). These gaps have motivated my dissertation researches.
In chapter one and two, I investigated the prospective associations of five subtypes of plasma phospholipid trans fatty acid (TFA) levels with the risk of various disease endpoints, including total, CVD and non-CVD mortality, incident coronary heart disease (CHD) and DM. In chapter two, I also examined the prospective associations of total and subclasses dietary TFA with risk of DM. The analyses were conducted using the Cardiovascular Health Study, a community-based multicenter prospective cohort consisted of older Americans. The risks were estimated using the Cox proportional hazard model.
The study in chapter three was a collaborative effort of the Nutrition and Chronic Diseases Expert Group as part of the 2010 Global Burden of Diseases, Injuries, and Risk Factors study. Using the comparative risk assessment framework, I comprehensively quantified the CHD mortality attributable to suboptimal intakes of saturated fat, omega-6 polyunsaturated fat, and TFA in 186 countries in 1990 and 2010, by age and sex groups. I also estimated the regional and country level trends of these attributable CHD burdens from 1990 to 2010. The findings of this study are relevant for informing regional and country level public health policy priorities.
38
Di, Nunzio Mattia <1980>. "N-3 fatty acids and cardiovascular prevention." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2162/1/Di_Nunzio_Mattia_tesi.pdf.
Texto completoResumen
In this study we elucidate the role of polyunsaturated fatty acids (PUFAs) in the prevention of cardiovascular diseases, focusing the attention on their role in the
modulation of acyl composition of cell lipids and of gene expression. Regarding this latter mechanism, the effectiveness of PUFAs as activators of two transcriptional factors, SREBPs and PPARs, have been considered. Two different model system have been used: primary cultures of neonatal rat cardiomyocytes and an human hepatoma cell line (HepG2). Cells have been supplemented with different PUFAs at physiological concentration, and special attention
has been devoted to the main n-3 PUFAs, EPA and DHA.
PUFAs influence on global gene expression in cardiomyocytes has been evaluated using microarray technique. Furthermore, since it is not fully elucidated which transcription factors are involved in this modulation in the heart, expression and activation of the three different PPAR isoforms have been investigated. Hepatocytes have been used as experimental model system in the evaluation of PUFAs effect on SREBP activity. SREBPs are considered the main regulator of cholesterol and triglyceride synthesis, which occur mainly in the liver. In both experimental models the modification of cell lipid fatty acid composition subsequent to PUFAs supplementation has been evaluated, and related to the effects observed at molecular level. The global vision given by the obtained results may be important for addressing new researches and be useful to educators and policy makers in setting recommendations for reaching optimal health through good nutrition.
39
Di, Nunzio Mattia <1980>. "N-3 fatty acids and cardiovascular prevention." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2162/.
Texto completoResumen
In this study we elucidate the role of polyunsaturated fatty acids (PUFAs) in the prevention of cardiovascular diseases, focusing the attention on their role in the
modulation of acyl composition of cell lipids and of gene expression. Regarding this latter mechanism, the effectiveness of PUFAs as activators of two transcriptional factors, SREBPs and PPARs, have been considered. Two different model system have been used: primary cultures of neonatal rat cardiomyocytes and an human hepatoma cell line (HepG2). Cells have been supplemented with different PUFAs at physiological concentration, and special attention
has been devoted to the main n-3 PUFAs, EPA and DHA.
PUFAs influence on global gene expression in cardiomyocytes has been evaluated using microarray technique. Furthermore, since it is not fully elucidated which transcription factors are involved in this modulation in the heart, expression and activation of the three different PPAR isoforms have been investigated. Hepatocytes have been used as experimental model system in the evaluation of PUFAs effect on SREBP activity. SREBPs are considered the main regulator of cholesterol and triglyceride synthesis, which occur mainly in the liver. In both experimental models the modification of cell lipid fatty acid composition subsequent to PUFAs supplementation has been evaluated, and related to the effects observed at molecular level. The global vision given by the obtained results may be important for addressing new researches and be useful to educators and policy makers in setting recommendations for reaching optimal health through good nutrition.
40
MAININI, FRANCESCA. "ESTERIFICATION OF NATURAL COMPOUNDS WITH FATTY ACIDS." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/170495.
Texto completoResumen
In this PhD project we dealt with β-sitosterol, resveratrol and quercetin, three natural substances featuring ascertained biological activities. These compounds are characterized by a limited bioavailability and a low stability: these features reduce their application in pharmaceutical, nutraceutical and dermocosmetic areas. In order to improve the above mentioned properties, we synthesized esters of these compounds, following either a chemical approach (resveratrol, quercetin, and β-sitosterol) and a enzymatic approach (resveratrol and β-sitosterol). The esterification was performed with saturated (palmitic and stearic) and unsaturated (oleic, linoleic and linolenic) fatty acids: this synthesis introduced in a single molecule (prodrug) two moieties both pharmacologically active.
Chemical synthesis was used to obtain resveratrol triesters, but failed with diesters: so these derivatives were synthesized by enzymatic approach. 1H-NMR and 13C-NMR analyses allowed to define the structure of these derivatives.
The synthesis of quercetin penta, tetra and triesters was obtained by modulating the acid/quercetin molar ratio; mono- and bi-dimensional NMR techniques were used to determine the structure of all quercetin esters, while for triester computational studies were needed.
In addition, for resveratrol and quercetin esters the antioxidant activity was evaluated: this property was not increased by esterification. Also the bioavailability was studied for resveratrol and its trioleoyl ester, but the resveratrol resulted more bioavailable in comparison with its ester.
In order to improve drug topical delivery, quercetin and its derivatives were also incorporated in liposome formulations.
41
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.
Texto completoResumen
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.
42
Hauff, Simone [Verfasser]. "Methyl-Branched Fatty Acids and Chiral Anteiso-Fatty Acids in Neutral and Polar Lipids of Biological Samples / Simone Hauff." Aachen : Shaker, 2010. http://d-nb.info/108188570X/34.
Texto completo
43
MUREDDA, LAURA. "Modulation of gene expression of GPR fatty acids sensors/receptors by dietary fatty acids influences inflammatory response in adipocytes." Doctoral thesis, Università degli Studi di Cagliari, 2017. http://hdl.handle.net/11584/249593.
Texto completoResumen
The fate of dietary fatty acids is finely regulated by specific cellular receptors capable of sensing the quantity and the quality of fatty acids reaching different organs via lipoproteins or as free fatty acids (FFAs). These receptors named GPR fatty acids receptors/sensors seem to play a fundamental role in governing the fate of dietary fatty acids in adipocytes.
Based on these features, in this work we evaluated the effect of free fatty acids on inflammatory markers and the involvement of GPR120 and GPR84 in modulating the inflammatory response in obesity as assessed in human adipocytes.
Cells were differentiated and incubated at 12 days post-induction of differentiation with inflammatory cytokines, hormones or fatty acids for 4 and 24 h. Both TNFα (tumor necrosis factor-α) and IL-1β induced a reduction in GPR120 expression at 4h and 24 h. In marked contrast, GPR84 mRNA level was dramatically increased by treatment with the pro-inflammatory cytokines. The PPARγ agonist rosiglitazone had no effect on GPR84 expression, but there was a stimulation of GPR120 expression which was most marked at 24 h. Dexamethasone and insulin had little or no effect on GPR120 and GPR84 expression. Docosahexaenoic acid (DHA) was able to increase GPR120 gene expression only after 24h of incubation while arachidonic acid (ARA) strongly decreased GPR120 gene expression at the same time point; both had no effect on GPR84 expression.
The GPR FFA receptors are sensitive to circulating levels of FFAs. In order to evaluate whether concentration of free DHA present in human plasma changes based on its dietary intake, we carried out a pilot study. Normalweight, overweight and obese subjects were treated with an intake of 2 g/d of EPA/DHA supplements in two different formulations: fish oil (FO) and Krill oil (KO). Control group was treated with olive oil (OO). Plasma free fatty acids, particularly those relevant for the effects on GPRs, namely EPA (eicosapentenoic acid), DHA, POA (palmitoleic acid) and ARA and also the plasmatic level of TNFα were taken into consideration. In overweight and obese subjects FO was more efficient in increasing plasma free DHA and POA, while in the case of KO it was EPA even though not significantly. In addition, we found that free ARA decreased with FO treatment leading to an increase of DHA/ARA ratio. This increase mirrored the decrease of TNFα. Interestingly the increase of DHA and POA was associated to a decrease of circulating TNFα. The changes were only evident in the obese subjects probably because they had higher levels of circulating FFAs, and higher concentration of TNFα.
Therefore, our data suggest that KO, as opposite to FO, being mostly incorporated into PLs, decreases circulating FFAs and thereby DHA and POA, with a possible less marked effect on GPR120 and consequent less efficient ability to reduce inflammation through this pathway. These data point out the importance not only on the type of dietary fatty acids but also on the formulation which may strongly influence their activities in lipid and energy metabolism in the obese by affecting the inflammatory response by targeting GPR120.
Future studies should be carried out in larger cohorts and possible modulation of resolvins and protectins biosynthesis should be taken into consideration. In addition, we will aim to evaluate whether in experimental animals and humans the dietary fats by modifying fatty acid profile in different lipid fractions may modulate omega-3 effects, affecting metabolic dysfunction and/or inflammation.
44
Hawkes, Joanna Susan. "N-3 fatty acids, eicosanoids and control of inflammation /." Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phh392.pdf.
Texto completoResumen
Thesis (Ph. D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, and Rheumatology Unit, Royal Adelaide Hospital, 1994.<br>Errata slip inserted. Includes bibliographical references (leaves 178-199).
45
富洵 and Xun Fu. "Lipase selectivity in reactions involving natural and synthetic fatty acids and fatty alcohols." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124015X.
Texto completo
46
Fu, Xun. "Lipase selectivity in reactions involving natural and synthetic fatty acids and fatty alcohols /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22032435.
Texto completo
47
Kling, Marcel Robert. "Synthesis of very long chain fatty acid methyl esters /." Title page, table of contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phk65.pdf.
Texto completo
48
Lewis, Amanda Gloria. "Treatment of Hypertriglyceridemia with Omega-3 Fatty Acids: A Systematic Review." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd458.pdf.
Texto completo
49
Gardiner, Neil Stockenstrom. "Essential fatty acids and ascorbic acid- interactions and effects on melanoma growth." Thesis, Rhodes University, 1990. http://hdl.handle.net/10962/d1018230.
Texto completoResumen
The present study was carried out to determine the effects and possible mechanisms of action of the essential fatty acids (EFAs) (linoleic acid (LA), gamma-linolenic acid (GLA) and arachidonic acid (AA)) and ascorbic acid (Asc) on BL6 murine melanoma growth in cell culture and in mice. Interactions between the nutrients in influencing melanoma growth as well as possible mechanisms of the interactions were also examined in the above systems. Cell culture studies revealed that all three EFAs (0-SOμg/ml) and Asc (0-200μg/ml) significantly inhibited melanoma growth at the concentrations used. The EF As were also found to significantly inhibit growth, although to a lesser extent than BL6 cells, of monkey kidney (LLCMK) cells which were used as a non-malignant control cell line. Asc in contrast was found not to inhibit growth of these cells. Supplementation of Asc (lOO)μg/ml) to EFA containing (0-50μg/ml) medium was found to significantly increase inhibition of cell growth in both cell lines, and in the BL6 cells in particular, after taking into account the growth inhibitory effects of Asc in the absence of EFAs. The mechanism of cell growth inhibition by the EF As appeared to involve lipid peroxidation but not enhanced prostaglandin (PG) or leukotriene (LT) synthesis. While Asc was found to increase both lipid peroxidation and PG synthesis in the cells, these mechanisms and enhanced LT synthesis did not appear to have played a role in the inhibition of cell growth by Asc or in the growth inhibitory interaction between Asc and the EF As. In vivo studies revealed that diets containing essential or polyunsaturated fatty acids (EFAs/PUFAs) in the form of vegetable oils, and in particular GLA in the form of evening primrose oil, significantly promoted melanoma growth in mice when compared with an EFA/PUFA free diet containing predominantly saturated fats (SF). Supplementary dietary Asc in contrast was found to significantly inhibit melanoma growth in mice fed EFA/PUFA, and in particular GLA, containing diets but not in mice fed SF cont~g diets. This result appears to indicate the occurrence of an interaction between the two nutrients. Ul The mechanism of tumour promotion by the EP As/PUP As did not appear to have involved enhanced PG or LT synthesis or lipid peroxidation. Since dietary EPA/PUPA manipulation was found to significantly alter the EPA content of tissues, including the melanomas, the mechanism of tumour promotion may have involved changes in the EPA composition of the tumour cells. While supplementary Asc was found to significantly increase the Asc content of certain tissues, including the melanomas, which may have played a role in tumour growth inhibition by Asc, it was found not to affect the EPA content of tissues. Enhanced PG or LT synthesis and lipid perox:idation did not appear to have been involved in the tumour growth inhibitory interaction between Asc and the EP As/PUP As. THe activity of the enzyme delta-6-desaturase, a key enzyme in EF A metabolism which catalyses the desaturation of LA to GLA, and the influence of Asc on activity of the enzyme were also examined. The cultured cells, and BL6 cells in particular, were found to contain significant activity of the enzyme. Whereas murine liver microsomal fractions were found to contain delta-6-desaturase activity, microsomes from melanomas grown in mice were found to lack activity of the enzyme. The significant tumour promoting effects of the GLA containing EPO diet may have been the result of the lack of delta-6-desaturase activity in tumour cells grown in mice. Asc was found to stimulate activity of the enzyme in cultured BL6 cells but not in LLCM.K cells, while dietary Asc and EF A/PUP A manipulation did not influence activity of the enzyme in microsomal fractions. This study has confirmed previous reports of the in vivo tumour promoting effects of dietary EP As/PUP As and the tumour growth inhibitory effects of Asc. The in vitro cell growth inhibitory effects of Asc and the EP As also confirm the results of previous reports. Previous studies investigating possible interactions between Asc and EP As/PUP As in influencing tumour cell growth could not be located in the relevant literature. This study may therefore be one of the first investigations of any such interaction between these nutrients in tumour cells. While this study was not able to identify the mechanisms involved in the different tumour promoting or tumour growth inhibitory effects of the two nutrients in the two systems, it did eliminate a number of potential mechanisms. The results of this study also emphasise the difficulty of attempting to compare the results of in vitro and in vivo studies.
50
Orchard, Tonya Sue. "Fatty Acids and Risk of Fracture in Postmenopausal Women." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306513275.
Texto completo