Dissertationen zum Thema „Synthèse des acides gras“
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Durand-Meulien, Sandrine. „Synthèse d'acides gras polyinsaturés et de métabolites“. Aix-Marseille 3, 1998. http://www.theses.fr/1998AIX30058.
Der volle Inhalt der QuelleServat, Francisco. „Synthèse d'amides gras N substitués par catalyse enzymatique“. Montpellier 2, 1990. http://www.theses.fr/1990MON20044.
Der volle Inhalt der QuelleRedmann, Inès. „Synthèse enzymatique d'esters d'acides gras et de saccharides“. Toulouse, INPT, 1995. http://www.theses.fr/1995INPT041G.
Der volle Inhalt der QuelleHarmange, Jean-Christophe. „Synthèse totale énantiosélective d'acétogénines d'Annonacées (gamma-lactones monotétrahydroguraniques)“. Paris 11, 1992. http://www.theses.fr/1992PA114840.
Der volle Inhalt der QuelleGranger, Louis-Marie. „Caractérisation cinétique et stoechiométrique de la synthèse d'acides gras chez Rhodotorula glutinis“. Toulouse, INSA, 1992. http://www.theses.fr/1992ISAT0001.
Der volle Inhalt der QuelleSoto, Thierry. „Synthèse asymétrique d'analogues pincés de l'acide arachidonique“. Aix-Marseille 3, 1995. http://www.theses.fr/1995AIX30077.
Der volle Inhalt der QuelleAchard, fabienne. „Acides gras d'origine marine : métabolisme et effets sur la synthèse de prostacycline endothéliale“. Lyon, INSA, 1995. http://www.theses.fr/1995ISAL0087.
Der volle Inhalt der QuelleThe investigated the role and metabolism of n-3 fatty acids from marine oil (eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids) in bovine aortic endothelial cells. First, we studied the anti-aggregant potential of endothelial cells enriched with EPA or DHA, and their capacity to synthetize prostacyclin. We showed that n-3 fatty acids treated cells were less active than control cells in inhibiting platelet aggregation and in producing prostacyclin, and these phenanena have been positively correlated. In the second part, the metanolic fate of EPA and DHA was studied. He found that they were actively interconverted by endothelial cells, leading to DPA accumulation. In addition, enrichment with n-3 fatty acids modified the cellular concentration of other fatty acids, especially those of the n-6 series. Only EPA altered arachidonic acid concentration in phospholipids. Last, the inhibitory mechanisms displayed by n-3 fatty acids upon the prostacyclin Sjmthesis are analyzed. We observed that prostacyclin formation in n-3 fatty acids enriched cells was similarly inhibited whatever the source of arachidonic acid: endogenous or exogenous. These results suggest that the investigated fatty acids act rather on the enzymic conversion of arachidonic acid than on its avai1ability. We also found a decreased 1eve1 of PGHS-1 and of its transcript in enriched cells, suggesting some transcriptional effects
Sandri, Jacqueline. „Synthèses totales de l'EPA et du DHA“. Aix-Marseille 3, 1994. http://www.theses.fr/1994AIX30032.
Der volle Inhalt der QuelleLacoux, Xavier. „Synthèse et structures de peptides et d'acylpeptides, inhibiteurs potentiels de la fixation du V. I. H“. Montpellier 2, 1991. http://www.theses.fr/1991MON20154.
Der volle Inhalt der QuelleGargouri, Mohamed. „Valorisation d'huiles végétales par la voie enzymatique de la lipoxygénase : synthèse d'arômes dans des systèmes compartimentés“. La Rochelle, 1997. http://www.theses.fr/1997LAROS013.
Der volle Inhalt der QuelleBellahouel, Salima. „Synthèse de nouveaux tensioactifs biodégradables“. Montpellier 2, 1999. http://www.theses.fr/1999MON20090.
Der volle Inhalt der QuelleKhalfallah, Yadh. „Régulation par le glucose, l'insuline et les acides gras de la néoglucogenèse à partir du lactate chez l'homme“. Lyon 1, 1995. http://www.theses.fr/1995LYO1T027.
Der volle Inhalt der QuellePaubert, Marc. „Préparation et étude d'agents tensio-actifs dérivés d'acides gras monomères et dimères“. Toulouse, INPT, 1993. http://www.theses.fr/1993INPT048G.
Der volle Inhalt der QuelleHumbert, Thierry. „Synthèse d'acides gras [1-14C] β-méthyles : intérêt de ces acides comme biomarqueurs de la captation myocardique et de la viabilité cellulaire“. Université Joseph Fourier (Grenoble), 1991. http://www.theses.fr/1991GRE19001.
Der volle Inhalt der QuelleIacazio, Gilles. „Lipoxygénase-1 de soja. Synthèse préparative d'hydroperoxydes d'acides gras polyinsaturés. Etude d'une activité de type hydroperoxyde-lyase“. Aix-Marseille 3, 1990. http://www.theses.fr/1990AIX30077.
Der volle Inhalt der QuelleSoultani, Samia. „Synthèse enzymatique d'esters de fructose et d'acide gras : cinétique, purification et caractérisation des propriétés tensioactives“. Vandoeuvre-les-Nancy, INPL, 2001. http://docnum.univ-lorraine.fr/public/INPL_T_2001_SOULTANI_S.pdf.
Der volle Inhalt der QuelleThis work aims to study kinetics, purification and surfactive properties of sugar esters obtained by enzymatic synthesis. Fructose and various fatty acids (C8 to C18) were used as substrates. These syntheses were carried out in methyl-2 butanol-2, at 60°C and in the presence of an immobilized Candida antarctica lipase as biocatalyst. From the kinetic point of view, the results obtained show that the activity of this enzyme is influenced by substrate concentrations, hydrophobicity and the level of water in the medium. By a judicious control of the synthesis environment, it was possible to convert the quasi totality of the substrates (>90 %) with concentrations bordering the 140 g/1. The monoesters/diesters selectivity was affected by the macro-environment of the system. The purification of the monoesters from the residual substrates was carried out successfully by a liquid-liquid extraction. The purity of the obtained products is about 99 % with losses less than 7%. These extractions were carried out on three sugaresters (C1O, C14 and C18). The characterization of the properties of the sugaresters in a pure state or in mixture with diesters showed that these molecules are as efficient as sucrose esters. They allow to stabilize H/E emulsions and to lower rapeseed oil/water interfacial tensions. In the same way, they have a high foaming capacity
Mnasri, Taha. „Synthèse enzymatique de lysophosphatidylcholines“. Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1017.
Der volle Inhalt der QuelleThe Lysophosphatidylcholines (LPCs), amphiphilic molecules, can act as a carrier for fatty acids of interest. These molecules can be synthesized enzymatically. This work aims to synthesize LPCs containing mono or poly unsaturated fatty acids enzymatically. Sn-3-glycerophosphatidylcholine (GPC), oleic acid (C18: 1, 9ω), linoleic acid (C18: 2, 6ω) and docosahexaenoic acid (C22: 6, 3ω) were used as substrates. These syntheses were performed by esterification without solvent using an immobilized lipase. From kinetic point of view, optimization of conditions for synthesis of oleoyl-LPC was carried out by studying each factor independently. The obtained optimal conditions are : Lipozyme RM-IM (10% w/w), a molar ratio of 20 (oleic acid / GPC), neither addition or elimination of water was applied to the reaction mixture, a temperature at 50° C and stirring at 750rpm. These conditions allow to obtain 75% oleoyl-LPC within 24 hours. The oleoyl-LPC was purified on a silica cartridge and analyzed by MS to confirm its identity. The optimization of linoleoyl-LPC synthesis was made using a design of experiments. This is an approach that can simultaneously vary the parameters studied. Among the 17 combinations studied, one combination allows to obtain 93% of linoleoyl-LPC in 6 hours. This result was confirmed by repeating this manipulation 4 times. Like oleoyl-LPC linoleoyl-LPC was purified and characterized by MS. Preliminary trials have shown that the syntheis of DHA-LPC is feasible. 30% of DHA-LPC was obtained after 72h of reaction. Finally, it should be noted that the produced amount of di-acyl-PC is always low compared to that of the acyl-LPC. This latter is explained by a low appearance of the phenomenon of acyl migration
Requirand, Nathalie. „Synthèse de dérivés fluorés et F-alkylés en série undécanoi͏̈que“. Montpellier 2, 1992. http://www.theses.fr/1992MON20157.
Der volle Inhalt der QuelleMeynadier, Annabelle. „Synthèse ruminale et sécrétion mammaire de l'acide linoléique conjugué (CLA) chez la vache laitière : effets des acides gras polyinsaturés alimentaires et du pH ruminal“. Aix-Marseille 3, 2004. http://www.theses.fr/2004AIX30043.
Der volle Inhalt der QuelleCLA is a fatty acid from cow milk, that has some interesting dietetic properties for human. It is synthesised in the rumen by isomerization of linoleic acid (C18:2) and in the mammary gland by desaturation of trans-vaccenic acid (C18:1t11). Several factors modulate its content in dairy milk, but only feeding is easy to modify and efficient. Several studies were done to control more exactly the effects of three great dietary factors of variation of CLA and C18:1t11 ruminal production : ruminal pH, amounts of unsaturated fatty acids, and physical treatment of fat source. Low ruminal pH increased amount of CLA in the rumen but decreased its mammary production ; pH near neutrality allowed a ruminal accumulation of CLA and C18:1t11. Added great quantities of C18:2, in particular extruded soybeans, intensified this accumulation. Increased CLA and C18:1t11 production in the rumen led to an increase of CLA content in milk
Coulon, Denis. „Étude d'un procédé de synthèse enzymatique d'esters de sucre et d'acide gras“. Vandoeuvre-les-Nancy, INPL, 1997. http://docnum.univ-lorraine.fr/public/INPL_T_1997_COULON_D.pdf.
Der volle Inhalt der QuelleNlandu-Mputu, Madeleine. „Identification des enzymes intervenant dans le transfert des acides gras dans les végétaux : spécificité de ces enzymes vis-à-vis de la prise en charge d'acides gras inhabituels“. Compiègne, 2009. http://www.theses.fr/2009COMP1847.
Der volle Inhalt der QuelleBranched chain fatty acids are of particular interest for the oleo-chemical industry. The cloning of genes involved in their biosynthesis has led scientists toward the design of new high value oilseed crops. However, their research resulted in very modest accumulation in seeds (less than 25 %) due to a limited knowledge of the lipid metabolism and fatty acids transfer in plants. Ln this context, we aimed to better understand the hpid synthesis and storage in oilseed plants and particularly, the substrate specificity and selectivity of Kennedy pathway acyltransferases (G3PAT, LPAAT and DAGAT) which are required for the incorporation of these fatty acids into storage triacylglycerols. Dur assays demonstrated that the G3PAT of the three studied species (flaxseed, rapeseed and castor beau seed) show no specificity toward usual and unusual substrates incorporation at the sn-l position of the triacylglycerol. But, our study shows that LPAAT and DAGAT have a limited ability to incorporate branched chain fatty acids at the sn-2 and sn-3 positions of the triacylglycerol due to their low specific and sélective activities for unusual substrates. However, the flaxseed LPAAT present a cyclopropane acyl-CoA incorporation rate similar to that observed for the isolated and studied litchi LPAAT in this study. In addition, our results show that other alternative pathways (PDAT, CPT, PLA) exist in unusual fatty acid producing plants for their efficient accumulation into triacylglycerides such as must be the case of the castor bean to explain the high level hydroxy fatty acid in its seed oil. Successful production of high value oilseed crops depends on : i) the optimization of unusual fatty acid precursor production, ii) the identification of high selectivity enzymes and iii) a better knowledge of branched chain fatty acid transfer mechanisms into triacylglycerols
Peyrou, Gilles. „Valorisation du glycérol : synthèse et production de monoglycérides purs par condensation des acides gras et du glycidol catalysée par les résines échangeuses d'anions“. Toulouse, INPT, 1996. http://www.theses.fr/1996INPT002G.
Der volle Inhalt der QuelleCaijo, Frédéric. „Synthèse d'analogues du 8(S)-HETE et étude de leur interaction avec les PPARs en vue d'applications thérapeutiques, notamment antidiabétiques“. Rennes 1, 2004. http://www.theses.fr/2004REN10088.
Der volle Inhalt der QuellePrakesh, Michaël. „Synthèse stéréocontrôlée de fluorés allyliques via les fluorés propargyliques. Application à la synthèse d'analogues fluorés de lipides“. Rennes 1, 2002. http://www.theses.fr/2002REN10140.
Der volle Inhalt der QuellePoidevin, Mickaël. „La synthèse d'acides gras dans des cellules spécialisées agit à distance sur le processus d'activation des ovocytes chez la drosophile“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL016.
Der volle Inhalt der QuelleA statistical study by the World Health Organization revealed that one adult over six is affected by infertility problems. This major social issue is complex and multifactorial, with worldwide trends that are difficult to assess. It is therefore essential to carry out more research to better understand not only the evolution of infertility, but also the cellular and molecular mechanisms leading to efficient fertility.Serendipitously, we discovered that a genetic screen to enzymes responsible for fatty acid synthesis in specialized Drosophila cells provoked a sterile phenotype. These specialized cells, called as oenocytes, are essential for fatty acid metabolism, and are involved in numerous processes, including lipid homeostasis, protection against desiccation and pheromonal communication.My work shows that the synthesis of one or more very long-chain fatty acids in oenocytes is essential for female fertility, and that a defect in this synthesis causes spermatozoa to be retaintion in the storage organs, spermathecae and seminal receptacle. I have shown that the sterility phenotype is not linked to a defect in sperm activity, and that sperm fertilize mature oocytes efficiently. On the other hand, my results indicate that the eggs show an activation defect preventing their development.In insects, activation of the mature oocyte, which leads to embryonic development, is not dependent on sperm entry as in mammals. This activation is triggered by a calcium signal while the oocyte moves through the female genital tract. Taken together, my results show for the first time that an extra-genital lipid-signal triggers the activation of mature oocytes, thus enabling the induction of embryonic development
Abboud, Hussein. „Coupure oxydante de doubles liaisons par le permanganate en solution aqueuse ou sur support solide, application à la synthèse de quelques amidoacides“. Amiens, 2011. http://www.theses.fr/2011AMIE0101.
Der volle Inhalt der QuelleOxidative cleavage of double bonds in unsaturated compounds has been widely developed, being a good way for synthesis of mono and dicarboxylic acids. Numerous reactants and a great variety of reaction conditions have been related. The aim objective of this thesis works is to perform this oxidation on various unsaturated compounds using an easy and, preferentially, under free solvent methods. We could demonstrate, by these works, that it was possible to use potassium permanganate as an oxidant in mild and eco-friendly conditions, without any organic solvent or additives, like emulsifiers or phase transfer agents. We could, by this way, perform synthesis of mono and dicarboxylic acids, starting from unsaturated fatty acids, or various olefins. In fact, two different synthetic pathways were performed; first one is only dedicated to unsaturated fatty acids, under their alkaline salts form. The second allows direct oxidation of crude fatty acids or olefins. In a second part, fatty amides issued from oleic acid were synthesized, silica gel being used as a solid support without any other coupling agent. These fatty amides were, after, oxidized by potassium permanganate to give, with good yields, interesting amido-acids. Two types of experimental conditions were validated: (i) We first showed that, when unsaturated fatty acids were under form of alkaline salts, it was possible to obtain, with high yields, mono and diacids by a simple oxidation in aqueous phase. (ii) It was also demonstrated that oxidation of unsaturated fatty acids under native form, or converted in amides or esters, or, still, non-volatile olefins, could be performed on solid support by potassium permanganate, with interesting yields and without use of organic solvents. It must be noticed that another attractive parameter of these oxidation methods is that it is possible to separate oxidation products by a simple precipitation, avoiding complex purification methods
Fonchy, Evelyne. „Etude de la synthèse d'esters d'acides gras à courte chaîne par "Pseudomonas fragi CRDA 037" par bioconversion en milieu aqueux“. Montpellier 2, 2000. http://www.theses.fr/2000MON20061.
Der volle Inhalt der QuelleLouis, Kévin. „Synthèse et fonctionnalisation d'aldéhydes issus de la coupure d'esters gras insaturés“. Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2290/document.
Der volle Inhalt der QuelleA high interest has been devoted to the use of renewable carbon in the chemical industry. The goal of this work is the substitution of fossil oils by vegetable oils to synthesize bio sourced monomers for polyesters and polyamides production. The synthesis of methyl 9-oxononanoate as a platform molecule from fatty acid methyl esters of rapeseed oil was carried out in solvent free ozonolysis at room temperature. Intermediary ozonides was reduced to aldehydes by catalytic hydrogenation under H2 pressure and in the presence of Pd(5)/C catalyst giving a 92% carbonyl yield. This process was applied to a wide range of unsaturated esters with a chain length within 9 and 13 carbon atoms. This process allows the selective conversion of renewable materials to value added chemicals, in mild conditions and in the presence of a recyclable catalyst. Moreover, the co products are non toxic and valuable. Hydrogenation of aldehyde group was performed in the presence of methanol at 50°C under hydrogen pressure. Raney Nickel and Pd(5)/C exhibit a yield to methyl 9 hydroxynonanoate higher than 90%. Reductive amination of the aldehyde functional group was investigated with success in the presence of NH3(g) and Pd(5)/C at 50°C in methanol to produce primary amino ester. The amount of ammoniac is directly correlated to the selectivity of the reaction. As a consequence a minimum amount of 3 eq. of ammoniac is required to avoid the formation of secondary amino-ester
Rosell, Mélissa. „Synthèse et évaluation de lipophénols deutérés, un nouveau concept pour réduire les stress oxydant et carbonylé dans les maladies rétiniennes“. Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT188/document.
Der volle Inhalt der QuelleAge Related Macular Degeneration (AMD) and Genetic Stargardt’s disease share a common cytotoxic mechanism involving carbonyl and oxidative stress. Hence both stresses represent promising therapeutic targets. A lipophenol lead molecule has been previously highlighted. This molecule is composed by an alkylphloroglucinol moiety and a lipid part which is a polyunsaturated fatty acid, the docosahexaenoic acid (DHA, C22:6, ω3). In order to improve the antioxidant activity of this lipophenol, the total synthesis of two deuterated DHA on bis-allylic positions was performed. The cross-coupling between the deuterated DHA and the alkylphloroglucinol moiety led to the corresponding deuterated lipophenols. The impact of the deuterium to limit the cell toxicity and the lipid peroxidation was highlighted thanks to in vitro biological studies performed on retinal pigment epithelium cell line
Brasseur, Edmond. „Recherche, synthèse et évaluation de « biolubrifiants » : peresters d'acides gras et de sorbitol“. Rouen, 1999. http://www.theses.fr/1999ROUES081.
Der volle Inhalt der QuelleSabin, Pascale. „Les huiles de colza et de tournesol dans les encres d'imprimerie : synthèse et caractérisation de nouvelles classes d'alkydes et formulations associées à base d'esters d'acides gras“. Toulouse, INPT, 1995. http://www.theses.fr/1995INPT045G.
Der volle Inhalt der QuelleGervais, Rachel. „Acides gras conjugués : Effets biologiques et intérêt pour moduler la synthèse des matières grasses du lait chez la vache“. Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26703/26703.pdf.
Der volle Inhalt der QuelleGeay, Florian. „Effets d'une alimentation végétale sur la biosynthèse des acides gras et le métabolisme du bar européen (Dicentrarchus labrax)“. Brest, 2011. http://www.theses.fr/2011BRES2018.
Der volle Inhalt der QuelleThe main objective of this thesis was to study the long-term effects of a diet exclusively composed by plant products on the metabolism of the European sea bass (Dicentrarchus labrax) and more particularly, on its capacity to biosynthesis the Highly Unsaturated Fatty Acids (HUFA) from the Polyunsaturated Fatty acids (PUFA) brought by this vegetal diet. Our transcriptomic approaches showed that the use of a plant food disrupted the lipids metabolism (cholesterol and fatty acids) and the energy metabolism (carbohydrates, amino acids) in the liver, but also affected other physiological processes such as the immune system. In spite of the regulation of the fatty acids metabolism in fish when fed with the vegetal diet, the European sea bass s not able to convert effectively the AGPI brought by this food into HUFA. In particular, this low conversion rate affects the fish quality for the consumer by reducing the HUFA content in the muscle. Such an incapacity to bioconvert high quantities of HUFA could be link to the low enzymatic activity of the delta-6-desaturase (FADS2) involved in the HUFA metabolic pathway. Our proteomic and transcriptomic approaches dedicated to the characterization of this enzyme showed the low level of the FADS2 activity measured in the liver and the intestine of sea bass fed with a plant food is not the consequence of a poor-functionality of the enzyme, but rather, a post-transcriptionnal regulation
Jamrozik, Claude. „Mise en oeuvre d'enzymes hydrolytiques pour l'acylation de la lysine par des acides gras en milieu organique“. Vandoeuvre-les-Nancy, INPL, 2001. http://www.theses.fr/2001INPL029N.
Der volle Inhalt der QuellePoisson, Laurent. „Valorisation enzymatique de lipides : synthèse de cires à partir de la matière grasse laitière : production et traitements d'acides gras polyinsaturés de microalgues“. Le Mans, 1999. http://www.theses.fr/1999LEMAA002.
Der volle Inhalt der QuelleGuihéneuf, Freddy. „Régulation par des facteurs environnementaux de la synthèse des acides gras à longue chaîne de différentes espèces de microalgues marines : effets combinés de l'éclairement et de la nature de la source carbonée sur l'optimisation de la synthèse de l'EPA et du DHA : intérêts nutritionnels“. Le Mans, 2008. http://www.theses.fr/2008LEMA1011.
Der volle Inhalt der QuelleBy their large amounts of omega-3 (EPA and DHA), marine microalgae are currently used in aquaculture for feeding invertebrates and in human nutrition for their beneficial effects on human health. In this context, the objective of this work was to study the influence of environmental factors on n-3 fatty acids synthesis in three microalgae species. It appears that the response to variations in growing conditions is specific to each species. Thus, the results can be used to optimize the cultivation conditions of microalgae producing n-3 fatty acids. Meanwhile, the study in rats shows that nutritional n-3 fatty acids from microalgae induced EPA tissue enrichment compared to regime based on fish oil. Consequently, microalgae could represent a possible alternative to fish oil in the prevention of cardiovascular diseases
Lescure, Régis. „Synthèse et propriétés de cétones aliphatiques à longue chaîne et de leurs dérivés azotés“. Montpellier 2, 1995. http://www.theses.fr/1995MON20212.
Der volle Inhalt der QuelleLomege, Juliette. „Synthèse d'additifs améliorant d'indice de viscosité issus de poly(méthacrylate de n-alkyle)s d'acides gras et leur application dans des huiles lubrifiantes“. Electronic Thesis or Diss., Montpellier, Ecole nationale supérieure de chimie, 2018. http://www.theses.fr/2018ENCM0008.
Der volle Inhalt der QuelleAbstract : Lubricating oils are formulated with "Viscosity Index Improver" (VII) additives in order to limit viscosity variation with temperature and thus maintain lubricity at high temperatures. VIIs are polymers of high molar masses which display a reduced solubility in oil at low temperatures resulting in an improvement of the polymer contribution on oil’s viscosity in temperature via the "coil expansion" mechanism. Among them, poly(n-alkyl methacrylate)s (PMA)s largely dominate the VII additives market but are mainly derived from petroleum resources. In such context combined with the increasing production of biolubricants, it seems interesting to develop biobased additives with similar chemical structures and properties than current PMAs. In order to achieve that purpose, fatty acids and their derivatives recently appeared as the perfect renewable resources since they are abundant in oil plants, cheap, compatible with base oils, functionalizable and they exhibit good natural lubricating properties. Nevertheless, they display a low reactivity through radical polymerization. Therefore, several available fatty acids have been functionalized with methacrylate groups to afford suitable monomers and the resulting polymers have demonstrated promising properties as VII in a mineral oil. The more performant VII was the high molecular weight poly(2-(methacryloyloxy)ethyloleate obtained by free radical polymerization whose properties have been optimized by grafting alkyl thiols on the internal unsaturation of the monomer from which it is derived. On the other hand, the same polymer demonstrated a strong affinity with a triglyceride lube oil due to their close structure avoiding the expansion of its rheological properties as VII in this type of oil. New polymeric structures with reduced solubility in triglyceride oils have therefore been developed to prepare suitable VIIs. In a first strategy, epoxy groups were incorporated into the structure of the poly(2-(methacryloyloxy)ethyloleate while in a second strategy, the monomer from which it is derived was copolymerized with comonomers of insoluble fatty amides in the reference triglyceride oil. The resulting (co)polymers have shown a similar rheological behavior in temperature than the current VII additives. Thus, the polymeric structures developed in this work represent promising alternatives to the use of current petroleum-based VII additives for applications in both mineral oils and triglyceride-type biobased oils
Borg, Pascale. „Comparaison entre différents procédés de synthèse de triacyglycérols d'acides gras polyinsaturés n-3 par voie enzymatique en milieu non-conventionnel“. Vandoeuvre-les-Nancy, INPL, 2000. http://www.theses.fr/2000INPL081N.
Der volle Inhalt der QuelleOzem, Hervé. „L'acide 3-méthyl-16-iodo-[carboxy-14C] hexadecanoïque : synthèse et application en tant que marqueur de viabilité myocardique“. Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE18007.
Der volle Inhalt der QuelleOger, Camille. „Synthèses totales de neuroprostanes de type F, dérivées du DHA, de l'EPA et de l'AdA“. Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20071.
Der volle Inhalt der QuelleDocosahexaenoïc acid (DHA, C22 :6 w3), eicosapentaenoïc acid (EPA, C20 : 5, w3) and adrenic acid (AdA, C22 :4 w6) are the major polyunstaurated acids in neuronal membrane. During an oxidative stress, their lipidic peroxidation led to oxygenated metabolites called neuroprostanes (NeuroPs). In order to access to new neuronal oxidtive stress biomarkers, we were interested in the syntheses of F-type NeuroPs derived from DHA, EPA and AdA
Jonzo-Hiol, Marie. „Purification et caractérisation des isoformes de la lipase de candida rugosa. Application à la synthèse des esters gras de stérols“. Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30079.
Der volle Inhalt der QuelleVeyron-Churlet, Romain. „Etude des interactions protéine-protéine au sein d'un processus vital : la biosynthèse des acides mycoliques chez Mycobacterium tuberculosis“. Toulouse 3, 2005. http://www.theses.fr/2005TOU30038.
Der volle Inhalt der QuelleThe genes coding for the enzymes implicated in the FAS-II system were cloned into vectors allowing the study of protein-protein interactions in a yeast two-hybrid system. This study was reinforced by a biochemical analysis based on co-immunoprecipitation experiments. We showed that there were both homotypic and heterotypic interactions between the enzymes implicated in the biosynthesis of mycolic acids. Moreover, these homotypic interactions proved to be essential since some variants of these proteins have a dominant negative effect when they are introduced in vivo into M. Tuberculosis, M. Bovis BCG and M. Smegmatis. Thus, we identified precise, specific and essential interactions whose suppression leads to the death of mycobacteria. All these interactions could represent a first step towards the identification of new peptidic or peptido-mimetics antibiotics that would be able to act by specifically targeting the protein-protein interactions, which are essential for mycobacteria
Aymé, Laure. „Biochimie fonctionnelle des diacylglycérol acyltransférases ; apports à la biologie de synthèse des huiles“. Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLA007.
Der volle Inhalt der QuelleTriacylglycerols (TAG) are an essential energy storage in many cells. Their composition is diverse; they are the main component of the seed oil for the food industry or used to produce industrial compounds. Acyl-CoA: diacylglycerol acyltransferase (DGAT) catalyze the final and rate-limiting step of TAG synthesis by transferring a fatty acid onto a diacylglycerol. In plants, there are three families, DGAT1, DGAT2 and DGAT3, sharing no homology and of unknown structure. It prevents any improvement of seed oil yield and quality by a rational approach. DGAT1 involvement in edible oil accumulation was demonstrated. In some plants, DGAT2 plays a key role in the synthesis of unusual TAG such as hydroxylated TAG found in castor oil and used to produce lubricants and bioplastics. DGAT3 contribution to TAG biosynthesis has not been demonstrated in planta. We studied three families of DGAT from the model plant Arabidopsis thaliana, belonging to the same family as oilseed rape, and a DGAT1 from oil palm, an industrial crop. DGAT expression in bacteria, yeasts and the study of mutant plant lines allowed us to characterize their activities. The modulation of yeast TAG content and composition induced by DGAT expression demonstrated the value of these enzymes for the production of tailored microbial oils
Wongdontree, Paprapach. „Staphylococcus aureus Adaptation to FASII-Targeted Antibiotics in Host Environments and Strategies to Potentiate Antibiotic Activities“. Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASB088.
Der volle Inhalt der QuelleStaphylococcus aureus is a common opportunist pathogen causing infections that are notoriously difficult to treat due to antibiotic failure. In 2019, S. aureus caused the highest mortality among pathogens. The need for new treatments spurred the development of a novel pipeline class of antibiotics targeting the fatty acid synthesis (FASII) pathway. However, the use of FASII antibiotics has an inherent flaw: S. aureus, and several Firmicute pathogens, are able to compensate FASII inhibition by incorporating environmental fatty acids (eFAs) as present in the host. The aim of my thesis project is to elucidate the factors contributing to this FASII antibiotic adaptation and to analyze the consequences on bacterial fitness. This information will be used to identify the weak points of anti-FASII-adapted S. aureus, and to develop a bi-therapy treatment coupled with anti-FASII. Two main findings are reported. 1) Using combined omics and physiological approaches, we show that anti-FASII adaptation reprograms S. aureus to be more oxidative stress resistant, but less virulent. These in vitro results were in accordance with studies in an insect model, showing that anti-FASII-adapted S. aureus killed insects slowly compared to non-treated S. aureus. Priming S. aureus with H₂O₂ accelerated FASII-antibiotic adaptation. Previously, H₂O₂ priming was reported to stimulate antibiotic efflux. In contrast, H2O2 priming stimulates fatty acid (FA) incorporation, thereby accelerating anti-FASII adaptation via a unique mechanism. As the host produces H₂O₂ as part of its antibacterial defense mechanism, FASII-antibiotic-adapted S. aureus may have a fitness advantage in some host biotopes. Collectively, reduced virulence and greater oxidative stress resistance may provide S. aureus a means to escape detection and persist in the host. Noted, this is the first report showing the link between oxidative stress and FA incorporation. 2) Our proteomics analyses revealed that a lipoteichoic acid (LTA) synthesis enzyme, “UgtP”, was turned off in anti-FASII-treated bacteria. Remarkably, after S. aureus adapts to anti-FASII, LTA was nearly non-detectable. This loss was observed regardless of the phospholipid FA composition. In view of LTA reported essentiality for S. aureus cell division and growth, we then questioned how S. aureus compensates LTA depletion. In contrast to LTA, wall teichoic acid (WTA) and cardiolipin (CL) pools increased in anti-FASII-adapted bacteria. This suggests that WTA and/ or CL might compensate LTA depletion and enable S. aureus to grow. Simultaneous removal of both TAs is reportedly lethal. Consequently, the LTA depletion observed in anti-FASII-adapted bacteria enabled us to demonstrate synergistic inhibition between anti-FASII and the WTA inhibitor, targocil, in S. aureus. Our work reveals that anti-FASII-adapted bacteria produce less virulence factors and are more oxidative stress-resistant. These findings reveal a link between oxidative stress and FA incorporation. They further suggest that an element of the FASII pathway exerts control on LTA synthesis. Altogether this work underlines the importance of membrane lipids in S. aureus pathogenesis and opens perspectives for designing bi-therapy treatments
Abidli, Abdelnasser. „Design of novel well-defined organorhenium heterogeneous catalyst for unsaturated fatty acid derivatives self-metathesis“. Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26473.
Der volle Inhalt der QuelleSustainable C-C bond forming reactions have been among the highest target of catalysis science and technology. In this scope, metathesis reaction has been gaining enormous attention due to the efficiency of the transformation process. Therefore, a great progress has been made in this area by developing several homogeneous and heterogeneous catalysts as well as distinct metathesis reaction approaches. This allows an easier and more sustainable design for various synthesis strategies in different fields including organic synthesis, polymer science, etc. However, the development of robust metathesis catalysts for large scale applications is still a challenging task. Taking this into account, this research presented in this doctoral dissertation is focusing on the synthesis of new heterogeneous metathesis catalysts. Therefore, methyltrioxorhenium (MTO) was supported on various alumina-based materials. The synthesized catalysts' performance was studied though methyl oleate self-metathesis, chosen as a model bulky functionalized substrate, in order to evaluate the active species tolerance to functional groups as well as to evaluate its diffusion inside the mesoporous channels. First, highly organized ZnCl2-modified OMA supports were successfully prepared through a sol-gel method followed by a post-synthesis modification via wet-impregnation process. MTO supported on these catalytic supports were found o be highly active for methyl oleate self-metathesis, displaying higher reaction rate and products selectivity compared to the conventional wormhole-like alumina-based catalysts. This improvement is ascribed to enhanced mass transfer phenomena inside the organized mesoporous network. Afterwards, we have developed efficient one-pot synthesis route ZnCl2-modified OMA supports. Interestingly, this approaches allowed access to numerous highly ordered ZnCl2-modified OMA supports with better synthesis yields and improved textural and surface properties. Moreover, these enhanced features allowed the MTO-based catalyst supported on these one-step prepared materials to exhibit higher metathesis reaction performance compared to ZnCl2-modified OMA supports prepared via the two-steps processes. However, spectroscopic investigations revealed the formation of similar surface active species for all the prepared catalytic supports. These characterizations guided us to study and propose a comprehensive mechanism of metathesis products formation pathways as well as the metathesis catalytic cycle, demonstrating the steric hindrance effect on the catalysts interface that governed the reaction selectivity. The synthesis of the 3 wt.% MTO/ZnCl2-OMA catalysts allowed us to efficiently perform metathesis reaction using renewable feedstock (e.g. fatty acid esters derived from vegetable oils), offering access to a variety of functionalized monomers which could be used for further transformations such as the synthesis of value-added bio-based polymers (e.g. bioplastics, biosurfactants).
Garenne, David. „Etude d'un système de transition basé sur des acides gras dans les processus d’encapsulation de biomolécules : vers un nouveau modèle de cellule minimale“. Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0365/document.
Der volle Inhalt der QuelleCompartmentalization is of importance for our understanding of the emergence of life on earth but also for the development and design of minimal cells. Coacervation phenomenon allows spontaneous sequestration by molecular diffusion from aqueous medium but do not allow encapsulation of molecule inside. On the contrary, vesicular systems do not allow spontaneous encapsulation of molecules inside. Here we introduce a model built from saturated long chain fatty acids. This system can form both membranous vesicles and membrane free coacervated droplets that result from clouding by decreasing ph. We have shown that a large amount of proteins is encapsulated into vesicles after pre-crowding into coacervated. Encapsulation of enzyme in vesicles allow to increase the reaction rate compared to the reaction rate in diluted medium. Synthesis of proteins by cell-free system and metabolic reactions with proteins of mollicutes have not clearly been shown but they represent an essential element in the development of a minimal cell
Mhanna, Ali. „Synthèse et formulation de résines photopolymérisables issues de la biomasse : application pour l'impression Braille“. Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS021/document.
Der volle Inhalt der QuelleThe work of the PhD deals with the synthesis of polymerizable monomers derived from biomass, the study of their photopolymerization and the characterization of the resulting materials. The formulated monomers were tested in a printing method of Braille characters.The monomers were prepared in a two-steps reaction that is simple, economic and environmentally friendly. The first step comprised a reaction between glycerol derivatives (glycerol carbonate or glycidol) and fatty acids. In the second step, the obtained [alpha]-monoglycerides were functionalized to obtain photopolymerizable monomers. The different obtained monomers that bear (meth)acrylate and/or epoxy groups were photopolymerized in a few seconds in the presence of photoinitiator.The photopolymerization kinetics were followed by FT-IR spectroscopy in ATR mode, and various parameters such as the amount and the nature of the photoinitiator, the irradiation intensity and the temperature were optimized. The different photocured materials were characterized to highlight their main physicochemical properties. Structure-properties relations were then established.Finally, a photopolymerizable formulation having a viscosity compatible with the printing process of Braille characters was developed by adding nanometric silice. The obtained Braille characters exhibited features close those carried out by the industrial partner
Nguyen, Thuy Linh. „Vers la synthèse totale de la mycangimycine, un acide gras polyènique peroxydé, et synthèse d’analogues plus stables et simplifiés“. Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS542.
Der volle Inhalt der QuelleThe southern pine beetle (Dendroctonus frontalis) ecosystem has been strongly studied because of the economic losses of conifer production in North America. From these researches, it has emerged that this pine beetle possesses a very complex natural associations with trees, fungi, mites. Recently some reports indicated that a bacterian symbiont (Streptomyces sp. SPB74) produces an unprecedent polyene peroxide, named mycangimycin, which plays a role of antifungal and antiparasitic. This molecule is a polyenic fatty acid containing a 3,5-disubstituted 1,2-dioxolane ring which exhibits exceptional antifungal activity against a wide variety of fungi and activities as antimalarial agent against Plasmodium falciparum.In this manuscript, we reported some attempts towards the synthesis of mycangimycin, especially for the formation of 3,5-disubstituted-1,2-dioxolane moiety which could contribute promisingly to many biological activities as antimalarial and antifungal. The first work focused on the synthesis of the 3,5-disubsituted-1,2-dioxolane ring using cyclopropanols as intermediates, through an oxidative ring opening process. As a result of that, some saturated analogues of mycangimycin were prepared in relatively high yield. In the second part of this manuscript, we have developed an available methodology of nucleophile addition to the peroxycarbenium ions derived from Lewis acid-mediated ionization of 3-alkoxy-1,2-dioxolanes providing 3,5-disubstituted-1,2-dioxolane compounds. Various synthetic analogues or intermediates have been evaluated in in vitro in antiparasitic domains
Guiard, Julie. „Synthèse d'antigènes présentés par la protéine CD1b, analogues des sulfoglycolipides diacylés mycobactériens : vers un nouveau vaccin contre la tuberculose“. Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00282233.
Der volle Inhalt der QuelleL'objectif de cette thèse était de synthétiser des analogues de ces Ac2SGL différant par la structure de leur partie lipidique. Une voie de synthèse générale de ces sulfoglycolipides (SGL) a été mise au point et plusieurs acides gras chiraux ont été synthétisés de façon stéréospécifique. Ainsi, une vingtaine d'analogues ont été obtenus pour évaluer leur activité antigénique in vitro.
Cette étude montre que les structures des deux chaînes lipidiques contrôlent la reconnaissance des complexes CD1b:SGL par le récepteur des lymphocytes T.
De plus, certains analogues ont montré une activité comparable à celle des Ac2SGL naturels et sont accessibles en quantité suffisante pour évaluer leur pouvoir protecteur chez le cochon d'Inde.