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Baik, Youngmin. "Carbothermal synthesis of aluminum nitride using sucrose". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60643.
Pełny tekst źródłaHawker, John Seth. "Sucrose and starch metabolism in leaves, storage organs and developing fruits of higher plants". Title page, contents and summary only, 1988. http://web4.library.adelaide.edu.au/theses/09SD/09sdh392.pdf.
Pełny tekst źródłaLunn, John Edward. "The control of sucrose synthesis in non-photosynthetic tissues". Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304460.
Pełny tekst źródłaKochhar, Anuradha. "Assimilate partitioning and sucrose synthesis in Lamium album L". Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624185.
Pełny tekst źródłaVerges, Alizee. "Computer-aided design and engineering of sucrose-utilizing transglucosylases for oligosaccharide synthesis". Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0020/document.
Pełny tekst źródłaChemical synthesis of complex oligosaccharides still remains critical. Enzymes have emerged as powerful tools to circumvent chemical boundaries of glycochemistry. However, natural enzymes do not necessarily display the required properties and need to be optimized by molecular engineering. Combined use of chemistry and tailored biocatalysts may thus be attractive for exploring novel synthetic routes, especially for glyco-based vaccines development. The objective of this thesis was thus to apply semi-rational engineering strategies to Neisseria polysaccharea amylosucrase (NpAS), a sucrose-utilizing α-transglucosylase, in order to conceive novel substrate specificities and extend the potential of this enzyme to catalyze novel reactions, going beyond what nature has to offer. In a first study, a computer aided-approach was followed to reshape the active site of the enzyme (subsites +1, +2 and +3) for the recognition and α-1,4 glucosylation of a non-natural disaccharide acceptor molecule (allyl 2-deoxy-2-N-trichloroacetyl-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranose). The trisaccharide product is a building block for the chemo-enzymatic synthesis of oligosaccharides mimicking the repetitive units of the Shigella flexneri lipopolysaccharides, and ultimately, for the production of a vaccine against Shigellosis disease. Using computational tools dedicated to the automated protein design, combined with sequence analysis, a library of about 2.7x104 sequences was designed and experimentally constructed and screened. Altogether, 55 mutants were identified to be active on sucrose (the donor substrate), and one, called mutant F3, was subsequently found able to catalyze the α-1,4 glucosylation of the target disaccharide. Impressively, this mutant contained seven mutations in the first shell of the active site leading to a drastic reshaping of the catalytic pocket without significantly perturbing the original specificity for sucrose donor substrate. In a second study, three variants were identified from the screening of the semi-rational library on sole sucrose as displaying totally novel product specificities. They were further characterized, as well as their products, at both biochemical and structural level. These mutants, called 37G4, 39A8 and 47A10, contained between 7 and 11 mutations into their active site. They were found able to use sucrose and maltose (a reaction product from sucrose) as both donor and acceptor substrates to produce in varying amounts erlose (α-D-Glucopyranosyl-(1→4)-α-D-Glucopyranosyl-(1→2)-β-D-Fructose) and panose (α-D-Glucopyranosyl-(1→6)-α-D-Glucopyranosyl-(1→4)-α-D-glucose) trisaccharides, which are not produced at all by parental wild-type enzyme. Relatively high yields were obtained for the production of these molecules, which are known to have acariogenic and sweetening properties and could be of interest for food applications. In a last part, another mutant 30H3 was isolated due to its high activity on sucrose (6.5-fold improvement compared to wild-type activity) from primary screening of the library. When characterized, the mutant revealed a singular product profile compared to that of wild-type NpAS. It appeared highly efficient for the synthesis of soluble maltooligosaccharides of controlled size chains, from DP 3 to 21, and with a low polydispersity. No formation of insoluble polymer was found. The X-ray structure of the mutant was determined and revealed the opening of the catalytic pocket due to the presence of 9 mutations in the first sphere. Molecular dynamics simulations suggested a role of mutations onto flexibility of domain B’ that might interfere with oligosaccharide binding and explain product specificity of the mutant
Baguma, Yona. "Regulation of starch synthesis in cassava /". Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a478.pdf.
Pełny tekst źródłaKonishi, Teruko. "THE EXPRESSION OF SUCROSE SYNTHASE AND ITS ROLE IN PLANT β-GLUCAN SYNTHESIS". Kyoto University, 2002. http://hdl.handle.net/2433/149898.
Pełny tekst źródła0048
新制・課程博士
博士(農学)
甲第9606号
農博第1234号
新制||農||841(附属図書館)
学位論文||H14||N3638(農学部図書室)
UT51-2002-G364
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 酒井 富久美, 教授 關谷 次郎, 教授 島田 幹夫
学位規則第4条第1項該当
Gerber, Jacqués. "The phloem unloading and sucrose-sequestration pathway in the internodal stem tissue of the Saccharum hybrid var. NCo376". Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1003763.
Pełny tekst źródłaNell, Hanlie. "Genetic manipulation of sucrose-storing tissue to produce alternative products". Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/1136.
Pełny tekst źródłaTrollope, Kim Mary. "Engineering a fungal β-fructofuranosidase". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96757.
Pełny tekst źródłaENGLISH ABSTRACT: β-fructofuranosidases are hydrolytic enzymes that act on sucrose to yield the products glucose and fructose. Under high substrate conditions these enzymes display fructosyltransferase activity which results in the synthesis of fructooligosaccharides (FOS). Some enzymes display higher propensities for FOS synthesis than others, with the determinants of this activity remaining unclear. The consumption of FOS produces a prebiotic effect that positively alters the composition of the colonic microflora, and as a result is linked to improved human and animal health. The increased demand for FOS has necessitated the industrial production of these nutraceuticals. In enzymatic sucrose biotransformation processes operating at high substrate loading and temperatures between 50 and 60°C, β-fructofuranosidase activity is negatively influenced by glucose product inhibition and thermal instability. The aim of this study was therefore to engineer the Aspergillus japonicus β-fructofuranosidase, FopA, to improve a FOS synthesis bioprocess. A dual approach was employed to engineer FopA so as to increase the probability of obtaining an improved enzyme variant(s). A random mutagenesis approach was applied to harness the potential of the randomness of introduced mutations as precise structural knowledge of the enzyme regions involved in the phenotypic presentation of product inhibition, specific activity and thermal stability was unavailable. A semi-rational approach afforded the additional opportunity to reduce the number of variants to be screened, yet theoretically increased the functional content of the library. This study details the development of a method to rapidly quantify FOS using Fourier transform mid infrared attenuated total reflectance spectroscopy and multivariate data analysis. The method offers improvements over conventionally used high performance liquid chromatography in terms of reduced sample analysis times and the absence of toxic waste products. This is the first report on the direct screening of an enzyme variant library for FOS synthesis to identify improved variants and will significantly support future engineering of β-fructofuranosidases using random mutagenesis approaches. The random mutagenesis approach yielded a variant displaying limited relief from glucose inhibition. At the peak difference in performance, the variant produced 28% more FOS from the same amount of sucrose, when compared to the parent. The semi-rational approach, using a combined crystal structure and evolutionary-guided approach, yielded a four amino acid combination variant displaying improved specific activity and thermostability that was able to reduce the time to completion of an industrial-like FOS synthesis reaction by 26%. The positive outcome of the semi-rational approach showed that engineering loops regions in an enzyme is a feasible strategy to improve both specific activity and thermostability, most probably due to the modification of enzyme structural flexibility. A bioinformatic tool that enables the identification of β-fructofuranosidases displaying high-level FOS synthesis from protein sequence alone was also developed during the study. These investigations revealed conserved sequence motifs characteristic of enzymes displaying low- and high-level FOS synthesis and a structural loop, unique to the latter group, that were readily applicable identifiers of FOS synthesis capacity. The tool presented may also be useful to improve the understanding of the structure-function relationships of β-fructofuranosidases by facilitating the identification of variations in groups of enzymes that have been functionally sub-classified.
AFRIKAANSE OPSOMMING: β-fruktofuranosidases is hidrolitiese ensieme wat op sukrose inwerk en glukose en fruktose as produkte vorm. Onder toestande met hoë substraatkondisies vertoon hierdie ensieme fruktosieltransferase-aktiwiteit wat tot die sintese van frukto-oligosakkariede (FOS) lei. Sommige ensieme neig na ʼn hoër FOS-sintese as ander, maar die bepalende faktore vir hierdie aktiwiteit is nog onbekend. Die verbruik van FOS veroorsaak ʼn prebiotiese effek wat die samestelling van kolon mikroflora positief beïnvloed en met verhoogde mens- en dieregesondheid verbind word. Die verhoogde aanvraag vir FOS het die industriële produksie van hierdie nutraseutiese middel genoodsaak. Tydens ensiemgedrewe sukrose-biotransformasieprosesse by hoë substraatladings en temperature tussen 50 en 60 °C, word β-fruktofuranosidase-aktiwiteit negatief deur glukose produkonderdrukking en termiese onstabiliteit beïnvloed. Die doel van hierdie studie was dus om die Aspergillus japonicus β-fruktofuranosidase, FopA, vir ʼn verbeterde FOS-sintese bioproses te manipuleer. ʼn Tweeledige benadering is vir FopA manipulasie gevolg om die waarskynlikheid van verbeterde variant(e) te verhoog. ʼn Lukrake mutagenese benadering, wat die potensiaal van ingevoegde mutasie ewekansigheid inspan, is in die lig van onvoldoende akkurate kennis van die strukturele gedeeltes betrokke by produkinhibisie-, spesifieke aktiwiteit- en termiese stabiliteit fenotipes gevolg. Die toepassing van ʼn semi-rasionele benadering het ook geleentheid vir die sifting van ʼn kleiner variantbibioloteek geskep, terwyl die funksionele inhoud teoreties verhoog word. Die studie beskryf die ontwikkeling van ʼn metode vir die vinnige kwantifisering van FOS, gebaseer op Fourier transform middel infrarooi geattenueerde totale refleksie spektroskopie en meerveranderlike data-analise. Dit is die eerste melding van ʼn direkte sifting van ʼn ensiemvariantversameling vir FOS-sintese om verbeterde variante te identifiseer, en kan die toekomstige manipulasie van β-fruktofuranosidases deur middel van lukrake mutagenese-benaderings beduidend ondersteun. Die lukrake mutagenese-benadering het ʼn variant met beperkte opheffing van glukose-onderdrukking gelewer. By die punt waar die prestasie die meeste verskil, het die variant 28% meer FOS vanaf dieselfde hoeveelheid sukrose geproduseer in vergelyking met die ouer-ensiem. Die semi-rasionele benadering, gegrond op ʼn kombinasie van kristalstruktuur en evolusionêre-geleide benaderings, het ʼn vier-aminosuurkombinasie variant met hoër spesifieke aktiwiteit en termostabiliteit gelewer wat die voltooiingstyd van ʼn tipiese industriële FOS sintesereaksie met 26% kon verkort. Die positiewe uitkoms van die semi-rasionele benadering het aangedui dat manipulasie van die lusgedeeltes in ʼn ensiem ʼn lewensvatbare strategie is om beide spesifieke aktiwiteit en termostabiliteit te verbeter, moontlik as gevolg van wysigings in die buigsaamheid van die ensiemstruktuur. ʼn Bioïnformatika-hulpmiddel vir die identifikasie van β-fruktofuranosidases met hoë vlakke van FOS-sintese op grond van proteïenvolgordes is ook tydens die studie ontwikkel. Motiewe met gekonserveerde volgordes kenmerkend van lae- en hoë-vlak FOS-produserende ensieme en ʼn strukturele lus, uniek tot die laasgenoemde groep, is tydens die ondersoek onthul wat as maklike identifiseerders van FOS-sintesekapasiteit kan dien. Die voorgestelde hulpmiddel kan ook nuttig wees om die struktuur-funksie-verwantskap van β-fruktofuranosidases beter te verstaan deur die identifikasie van variasie in ensiemgroepe wat funksioneel gesubklassifiseer is.
Baciu, Ioana Elena. "Extracted sugar-beet pulp and sucrose, two renewable materials as "hot" substrates for enzymatic synthesis of valuable saccharides". [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974178160.
Pełny tekst źródłaCorreia, Ricardo Miguel Paulino Barroso Dias. "Synthesis and characterization of sugar containing hydrophilic and hydrophobic polymers with potential application in medicine". Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11082.
Pełny tekst źródłaThere has been a worldwide acknowledgement that nature derived saccharides can provide the raw materials needed for the production of numerous industrial consumer goods. As such, sucrose is a low molecular weight renewable carbohydrate feedstock from which it is possible to elaborate new materials, like water-soluble and/or amphiphilic and biocompatible polymers. In this thesis we will describe some synthetic procedures (both conventional synthesis protocols (CSP) and microwave assisted protocols (MAPs)) by introducing and altering sugar hydroxyl groups, with the intent to produce functionalized polymers for use as biodegradable/biocompatible polymers with sugar linked side chains. The most widely used method for the synthesis of poly(vinyl saccharide)s has been based on free radical polymerizations of vinyl sugars. In this work, eleven compounds based on sucrose derivatization were synthesized using anhydrides, bromide halides, silyl chlorides, non-selective esterification and Mitsunobu reaction. Optimization and scale-up studies were made on monomer synthesis. Four of these compounds were used as monomers for radical copolymerization with styrene using as catalysts 2,2’-Azobis(2-methylpropionitrile) and sodium persulfate whether organic solvents or water was used as reaction media. From this copolymerization’s, four polymers were obtained and polystyrene was also synthesized to be used as a standard for comparison. The polymers, poly(1’,2,3,3’,4,4’,6-hepta-O-benzyl-6’-O-methacryloyl sucrose)-co-polystyrene, poly(1’,2,3,3’,4,4’,6’-hepta-O-acetyl-6-O-methacryloyl sucrose)-co-polystyrene, poly(6-O-methacryloyl sucrose)-co-polystyrene and poly(O-methacryloyl sucrose)-co-polystyrene, were characterized by Proton nuclear magnetic resonance (to assess sucrose vinyl ester/styrene ratio), Fourier transform infrared spectroscopy, Differential scanning calorimetry, Powder X-ray diffraction, Atomic force microscopy (topology studies as thin films and aggregates), Viscometry and polarimetry.
Zein, Marwan [Verfasser], i Hans-Joachim [Akademischer Betreuer] Joerdening. "Integration of Reaction and Product purification for trienzymatic catalyzed synthesis of Laminaribiose from Sucrose / Marwan Zein ; Betreuer: Hans-Joachim Joerdening". Braunschweig : Technische Universität Braunschweig, 2014. http://d-nb.info/117582027X/34.
Pełny tekst źródłaVelusamy, Mahesh. "New computational approaches for investigating the impact of mutations on the transglucosylation activity of sucrose phosphorylase enzyme". Thesis, La Réunion, 2018. http://www.theses.fr/2018LARE0045.
Pełny tekst źródłaIn this thesis, we explore the usage of computational approaches for understanding the link between mutations and changes in protein activity. Our study model is a bacterial sucrose phosphorylase enzyme from Bifidobacterium adolescentis (BaSP). This glycosyl hydrolase from family 13 (GH13) has been a focus in the industry due to its ability to synthesize original disaccharides and glycoconjugates. In fact, its activity is to transfer a glucose moiety from a donor sucrose to an acceptor which can be a monosaccharide or a hydroxylated aglycone. The enzymatic reaction proceeds by a double displacement with retention of configuration mechanism whereby a covalent glucosyl-enzyme intermediate is formed. However, it is at stake to control the regioselectivity of this transfer for it to be applicable at industrial level. This thesis aimed at providing a rational explanation for the observed impact of mutations on the regioselectivity of BaSP in view of controlling the synthesis of rare pre-biotic disaccharides like kojibiose and nigerose. We hypothesized that the preferred orientations of the acceptor determines the regioselectivity of the enzyme. In that respect, we used computational approaches to investigate the impact of mutations on the binding of the acceptor to the glucosyl-enzyme intermediate. The methodology used in this work opens the perspective of using computational approaches for engineering the regioselectivity of of glycosyl hydrolases with similar mechanism
Sacchetti, Annalisa. "Synthesis of mesoporous zeolites for the selective conversion of sugars into methyl lactate and other hydroxyesters". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16729/.
Pełny tekst źródłaKonowicz, Paul A. "Some synthetic transformations on sucrose". Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280931.
Pełny tekst źródłaSeabra, Joaquim Eugênio Abel 1981. "Avaliação tecnico-economica de opções para o aproveitamento integral da biomassa de cana no Brasil". [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265245.
Pełny tekst źródłaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-11T15:17:55Z (GMT). No. of bitstreams: 1 Seabra_JoaquimEugenioAbel_D.pdf: 2147529 bytes, checksum: e9ebd63f7d029f2346cd2c026285a2cf (MD5) Previous issue date: 2008
Resumo: O objetivo deste trabalho foi investigar, no cenário prospectivo, as opções tecnológicas que deverão permitir o melhor aproveitamento da biomassa da cana e suas possíveis implicações no contexto das usinas. Além das possibilidades envolvendo o uso mais diversificado da sacarose, este estudo investigou o aproveitamento do bagaço e palha da cana considerando quatro tecnologias: geração de. energia elétrica através da cogeração com ciclos a vapor (opção atualmente comercial); produção de etanol através da hidrólise (opções para curto, médio e longo prazo); geração de energia elétrica a partir da gasificação da biomassa integrada a ciclos combinados (BIG/GT -C C) (opções para médio-longo prazo); e a produção de combustíveis de síntese a partir da gasificação da biomassa (opções para médio-longo prazo). Para cada uma destas opções, foram discutidos os aspectos tecnológicos mais importantes e estimados os rendimentos e custos de sistemas integradps a uma usina de cana, além de terem sido avaliados seus efeitos nos balanços de energia e emissões de GEE. Neste trabalho ficou evidenciado o grande benefício econômico que pode representar o uso diversificado dos açúcares da cana para a produção de produtos de maior valor agregado, como aminoácidos, por exemplo. No caso da fibra da cana, foi avaliado que opções atualmente comerciais já propiciariam a geração de excedentes de energia elétrica superiores a 140 kWh/tc, com custos em tomo de 100 R$/MWh, para os casos de cogeração com alta pressão e uso de alguma palha em conjunto com o bagaço. Para o futuro, sistemas de cogeração com ciclos combinados deverão permitir que os níveis de excedentes ultrapassem os 200 kWh/tc, mas com custos também superiores (> 140 R$/MWh). Pensando na produção de combustíveis, as opções de curto prazo para a conversão bioquímica do bagaço possibilitariam um aumento na produção de etanol de cerca de 20 L/tc (a um custo de ~680 R$/m
Abstract: The objective of the present work was to investigate, in the prospective scenario, the technology options that might lead to a better use of sugar cane biomass and their possible implications in the mills' context. Besides the possibilities involving the diversified use of cane's sugars, this study evaluated the use of bagasse and cane trash considering four technologies: power generation with c~nventional steam cycles (current options); ethanol production through biomass hydrolysis (options for short, middle and long term); power generation through biomass gasification integrated to combined cycles (BIG/GT -CC) (options for middle-Iong term); and the production of synthetic fuels through biomass gasification (options for middle-Iong term). For each one of these options, were discussed the main technological aspects and estimated the yields and costs for systems integrated to cane mills; their effects over energy and GHG emission balances were assessed as well. In this work was evidenced the great economical benefit which would represent the díversífied use of cane's sugars for the production of higher value products, such as amino acids, for example. For the fiber fraction, it was concluded that current commercial options could already lead to electricity surpluses as high as 140 kWh/tc, with costs around 100 R$/MWh, for those configurations with high pressure boilers and using some amount of trash in addition to bagasse. For the future, combined cycles systems might lead to electricity surpluses higher than 200 kWh/tc, but also with higher costs (> 140 R$/MWh). Regarding fuels production, the short term options for biochemical conversion would allow 20 L/tc ethanol production increasing (produced at ~680 R$/m3), while the long term yields could reach 40 L/tc, with costs at 270 R$/m3. For thermochemical conversion, in the middle-Iong term, Fischer- Tropsch liquids, for instance, could be produced with yields closed to 490 MJ/tc, at costs around 30 R$/GJ. As for energy and GHG emission balances, for the current situation the energy ratio of ethanol production was evaluated as 9.4, with a life cycle net avoided emission of 1.8 t C02eq/m3 anhydrous. But for 2020, considering the expectations about the evolution on cane production and the availability of advanced technologies for biomass use, the energy ratio might rise to 14.2, while net avoided emissions would reach 2.9 t C02eq/m3 anhydrous, based on the adoption ofBIG/GT-CC systems for biomass use. Bearing all these aspects in mind, a broader comparison of the effects of these technology options utilization on the overall mill performance is presented in the end of the study, pointing out their implications for the establishment of the future sugar cane bio-refineries
Doutorado
Doutor em Planejamento de Sistemas Energéticos
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Pełny tekst źródłaLEON-RUAUD, PASCALE. "Syntheses de nouveaux tensioactifs non ioniques derives de sucres. Applications en biologie". Rennes 1, 1990. http://www.theses.fr/1990REN10089.
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Pełny tekst źródłaMaurice, Catherine. "Synthese, etudes physico-chimique et electrochimique de tensio-actifs chiraux derives de sucres". Clermont-Ferrand 2, 1999. http://www.theses.fr/1999CLF22099.
Pełny tekst źródłaBui-Van, Tuan DICKO AMADOU. "SYNTHESE D'ACIDES -AMINOBORRONIQUES. ETUDES DU TRANSPORT DE SUCRES A TRAVERS UNE MEMBRANE ORGANIQUE LIQUIDE /". [S.l.] : [s.n.], 1999. ftp://ftp.scd.univ-metz.fr/pub/Theses/1999/Bui_Van.Tuan.SMZ9929.pdf.
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Pełny tekst źródłaWalther, Alexandre. "Synthèse totale de la (-)-Ménisdaurine". Phd thesis, Université de Haute Alsace - Mulhouse, 2010. http://tel.archives-ouvertes.fr/tel-00590454.
Pełny tekst źródłaBeniazza, Redouane. "Synthèse et désymétrisation de cycloheptatriènes silylés : application à la synthèse de mimes de sucres". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13898/document.
Pełny tekst źródłaThis work dealt with the synthesis of silylated cycloheptatrienes and their desymmetrisation toward the synthesis of sugar mimics. Calystegines analogues were synthesized and an unexpected rearrangement leading to an original nortropane skeleton was emphasized. In a second part, cycloheptatriene-norcaradiene (CHT-NCD) equilibrium was studied. Silylated cycloheptatriene were also shown to react through cycloaddition reaction with acylnitroso compounds, through cascade processes: electrocyclisation (CHT-NCD)-cycloaddition- cationique cyclopropane opening-cycloaddition, leading highly selectively to aminocarbasugars. Starting from methylsilylated CHT, 7 stereogenic centers, 5 C-O bonds and 2 C-N bonds were formed in only 3 steps. An enantioselective Hetero-Diels-Alder reaction was also developed
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Pełny tekst źródłaFerrières, Vincent. "Syntheses selectives de o-glycosides et d'azotures de glycosyle a partir de sucres non proteges - proprietes amphiphiles". Rennes 1, 1994. http://www.theses.fr/1994REN10159.
Pełny tekst źródłaMILIUS, ALAIN. "Tensioactifs perfluoroalkyles a finalite biomedicale. Synthese et evaluation des derives neutres et anioniques de sucres". Nice, 1991. http://www.theses.fr/1991NICE4480.
Pełny tekst źródłaHecquet, Laurence. "Synthese enzymatique d'analogues de sucres en vue de la production d'un arome a statut naturel". Clermont-Ferrand 2, 1992. http://www.theses.fr/1992CLF21367.
Pełny tekst źródłaScherrmann, Marie-Christine. "Utilisation de milieux reactionnels a base de sucres : etudes physicochimiques et applications en synthese organique". Paris 11, 1992. http://www.theses.fr/1992PA112320.
Pełny tekst źródłaFaurie, Benoit. "Les sucres et l'astringence : effet des polysaccharides présents dans le vin sur les interactions tanins-protéines". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0191/document.
Pełny tekst źródłaTannins play a key role in the organoleptic qualities of red wine. They are responsible for wine astringency, a dry, rought and puker sensation perceived in the mouth while tasting. This sensation is the consequence of a specific interaction between tannins and saliva proteins, mainly Proline Rich Protein (PRPs). The first part of this work was to study the influence of various sugars on the self-association of tannins process as well as tannins - proteins interactions. The colloidal behavior of a tannin (the epigallocatechin gallate - EGCG), as well as its interaction with a representative peptide IB9-14 of PRPs was studied in the presence of various simple sugars and polysaccharides. The parameters of the interaction were determined for all systems, highlighting the existence of an interaction between EGCG and sugars whose affinity seems to depend on the sugar polymerization degree. This interaction does not interfere, under the experimental conditions tested, on the association between tannins and peptide. The second part of this work was to realize the full synthesis of the protein IB9 including the peptidic sequence of IB9-14, and to study its interaction with two procyanidins: EGCG and dimer B3. The results show and confirm the influence of the length of the peptide chain interactions with tannins
Denis, Cécile. "Utilisation de milieux aqueux a base de tensioactifs glycosidiques ou de sucres amphiphiles en synthese organique". Rennes 1, 1995. http://www.theses.fr/1995REN10171.
Pełny tekst źródłaBOSSARD, FABIENNE. "Synthese de nouvelles molecules amphiphiles a partir d'esters d'aminoacides et de lactones ou anhydrolactones derivees de sucres". Reims, 1996. http://www.theses.fr/1996REIMS033.
Pełny tekst źródłaConcia, Alda Lisa. "Chemoenzymatic synthesis of sugar-related polyhydroxylated compounds, iminocyclitols and their derivatives as glycosidase inhibitors". Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/113239.
Pełny tekst źródłaLa reacción aldólica es uno de los métodos más útiles y potentes para la formación de enlaces carbono carbono que permite, simultáneamente, la funcionalización y generación de nuevos centros estereogénicos adyacentes. Las aldolasas dependientes del fosfato de dihidroxiacetona (DHAP) catalizan estereoselectivamente la adición aldólica de DHAP a una gran variedad de aldehídos aceptores y han sido objeto de numerosos estudios que demuestran su utilidad como catalizadores en síntesis orgánica asimétrica. La principal limitación de esta clase de aldolasa es su estricta especificidad por el sustrato dador, la DHAP, que es un reactivo costoso y químicamente inestable. Por ello, los estudios dirigidos a la eliminación de la necesidad de la utilización de DHAP mediante estrategias de ingeniería de reacción, evolución dirigida, o a través del descubrimiento de nuevas enzimas naturales, son de gran interés. En este contexto el descubrimiento de la D-fructosa 6-fosfato aldolasa (FSA), una enzima natural que acepta dihidroxiacetona (DHA) como dador, ha sido de enorme importancia. El objeto de esta tesis es la aplicación de aldolasas dependientes de DHA y DHAP a la síntesis de compuestos quirales bioactivos. Los iminociclitoles son una clase de glicomiméticos muy atractivos en química médica ya que poseen actividad inhibidora de glicosidasas y glicosiltransferasas y, por tanto, con un vasto potencial terapéutico para el tratamiento de enfermedades como diabetes, infecciones virales y cáncer, entre otras. En este trabajo se describe una metodología quimioenzimática para la preparación de desoxiazúcares e iminociclitoles cuyas etapas clave son nuevas adiciones aldólicas estereoselectivas de dihidroxiacetona (DHA) e hidroxiacetona (HA) a diferentes aldehídos catalizadas por FSA. Mediante esta estrategia se han obtenido los iminociclitoles 1-deoxinojirimicina, 1-deoximannojirimicina y sus derivados N-alquilados, 1,4-dideoxi-1,4-imino-D-arabinitol y 1,4,5 trideoxi-1,4-imino-D-arabinitol y los desoxiazúcares 1-deoxi-D-xilulosa y 1 deoxi-D-ido-hept-2-ulosa. El 1,4-dideoxi-1,4-imino-D-arabinitol (DAB) y su enantiómero (LAB) son pirrolidinas polihidroxiladas con una amplia actividad inhibidora de varias glicosidasas. Las pirrolizidinas polihidroxilados son una clase de iminociclitoles bicíclicos que también poseen una importante actividad biológica. En este trabajo se presenta una estrategia quimioenzimática que emplea aldolasas dependientes de DHA y DHAP, para la síntesis de DAB y LAB, de una colección de sus derivados 2-aminometílicos y conjugados 2 oxo-piperazinicos y de nuevas pirrolizidinas polihidroxiladas de la familia de las casuarinas, todos con potencial actividad inhibidora de glicosidasas.
Ma, Junjun. "Synthesis and Optimization of ‘Sugar tongs’ Lock Neutraligands of the Chemokine CXCL12". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS241.
Pełny tekst źródłaHeparan sulfate (HS) is a class of linear and highly sulfated polysaccharides widely present in animal tissues, onto the cell surface or into the extracellular matrix. HS is one of the most heterogeneous polymers and presents an alternation of highly sulfated domains (S domains) and weakly sulfated one (A domains). Exposition of those SAS domains at the cell surface permits the establishment of specific interactions with proteins displaying complementary charge topologies, leading to the regulation of their biological activities.CXCL12, a HS-binding protein, member of the chemokine family of pro-inflammatory mediators, is the unique natural ligand of CXCR4 receptor. CXCL12/CXCR4 signaling is involved in several biological processes, including hematopoiesis, immune response and cancer metastasis. The design of HS type ligands that could bind specifically to CXCL12 to block or modulate its interaction with its receptor should give access to therapeutic substance being able to modulate its activity and allow treatment of several cancer types. To this aim, we planed to construct a symmetric tridentate ligand of CXCL12 in which the reducing end (RE) and non-reducing end (NRE) of a short synthetic HS fragment (dp4) would be connected to ligands able to occupy part of the CXCR4 binding site. Thanks to previous investigation onto IFN-γ, a cytokine that binds tightly to HS chains, our lab already demonstrated that the preparation of SAS mimics should be reached by connecting two synthetic HS fragments (S domains) by their RE through a PEG-type spacer differing in length to mimic internal A domain. To adapt this strategy to the preparation of CXCL12 neutraligands and new type of SAS mimics, this PhD program aimed (i) to establish a general strategy of modification of the HS fragments RE and NRE, (ii) to setup efficient conditions of ligation reactions for (iii) the preparation of CXCL12 neutraligands as well as a second generation of SAS mimics. We selected our two orthogonal ligation reactions into the Click Chemistry panel: “the CuAAC” triazole formation and the “oxime ligation”. In order to setup the practicability of this strategy of transformation of the two HS fragments ends, we optimized reaction conditions onto model disaccharide derived from cellobiose. On one hand, by using thiol-ene coupling procedure reported by our lab, we introduced an amino group to the RE of this disaccharide and optimized reactions conditions of a one-pot diazotransfer reaction/CuAAC sequence, allowing the selective conversion of this amino group into azide and its coupling with alkyne derivatives. To demonstrate the robustness of this sequence, we applied it to the direct modification of free amino acids for the preparation of organofluorine derivatives. On the other hand, the installation of an aldehyde motif onto the NRE of the model compound was obtained via a three steps sequence involving a Tsuji-Trost decarboxylative allylation of the position O-4 of the NRE unit, dihydroxylation of the resulting allyl ether and finally oxidative cleavage of the formed diol. Besides exploring the possibility of the selectivity of the oxidative cleavage in favor of vicinal acyclic diols without affecting cyclic diols of the disaccharide backbone, we also optimized the reaction conditions of oxime ligation to obtain a second one-pot procedure of oxidative cleavage/oxime ligation for the rapid modification of the NRE of HS fragments. This strategy of functionalization of the RE and NRE of oligosaccharides was implemented into our current synthetic pathway of preparation of HS fragments: a tetrasaccharidic HS fragment was representatively modified using this strategy for the synthesis of CXCL12 neutraligands and SAS mimics
NEDELEC, ISABELLE. "Etude de l'influence de l'addition de sucres sur la reactivite et la selectivite en synthese organique en phase aqueuse". Paris 11, 1996. http://www.theses.fr/1996PA112113.
Pełny tekst źródłaGavel, Marine. "Nouveaux développements chimiques pour la conception d'inhibiteurs de glycosyltransférases Carbene-mediated quaternarization of the anomeric position of carbohydrates: synthesis of allylic ketopyranosides, access to the missing α-gluco and β-manno stereoisomers, and preparation of quaternary 2-deoxy 2-acetamido sugars Regio- and chemoselective deprotection of primary acetates by zirconium hydrides". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR09.
Pełny tekst źródłaThe goal of this project is to challenge the hypothesis that a non-natural sugar with a quaternary anomeric position might be the central core of a powerful and selective inhibitor of glycosyltransferase. Our design is relying on a key quaternary anomeric centre that provide the unique opportunity to incorporate in a single innovative structure the acceptor, the donor and the leaving group released during the formation of the glycosidic linkage. The functionnalization of the ketopyranosides that will be at the centre of this new class of potent glycosyltransferases inhibitors rely on original synthetic methods allowing introduction of a trimethylene phosphonate and regioselective deprotection of primary position of acetylated sugars for building alpha-1,6 glycosidic linkages
Pannecoucke, Xavier. "Synthese de phosphodiesters mixtes oxysterol-sucre, une premiere approche pour un ciblage tissulaire. Etudes physicochimiques des interactions oxysterol-membrane". Université Louis Pasteur (Strasbourg) (1971-2008), 1993. http://www.theses.fr/1993STR13166.
Pełny tekst źródłaLorin, Christelle. "Elaboration et evaluation en synthese stereocontrolee de vinyl sulfures et vinyl sulfones derives de sucres : nouvelles approches d'oxa- et d'azacycles d'interet biologique". Orléans, 1997. http://www.theses.fr/1997ORLE2044.
Pełny tekst źródłaSilva, Vinicius Barros Ribeiro da. "Synthèse et évaluation biologique de nouveaux dérivés imidazoliniques, thiazoliniques et d'aminosucres". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV022/document.
Pełny tekst źródłaThe epidemiological situation of infectious and parasitic diseases has presented significant changes worldwide. This group of diseases continues to pose challenges to prevention programs, such as the ebola virus epidemic, which is responsible for more than 11,000 deaths in 2015, the emergence of the zika virus in Brazil, the cases of schistosomiasis in the region of Corsica, France, in 2014, not including the exposure of patients to endemic areas in tropical countries. This scenario reflects the social transformations that have occurred in the last decades, characterized by accelerated urbanization, communication between continents, among other factors that contributed to the delineation of the current epidemiological profile of infectious and parasitic diseases worldwide. Schistosomiasis mansoni is a severe parasitosis caused by the Schistosoma mansoni trematode. Currently, praziquantel (PZQ) is the only drug capable of treating all the different forms of schistosomiasis. The imidazolidines are represented by a group of pentagonal heterocyclic substances possessing diverse biological activities, among them the schistosomicidal activity. The first objective of this work is the investigation of the schistosomicidal activity of new thioxoimidazolidine derivatives. In this context, 24 new arylidene-3-(2-chloro, 6-fluoro)-benzyl-imidazolidin-2-thioxo-4-one derivatives of (PTS) were obtained. After principal component analysis (PCA), the most dissimilar derivatives were evaluated biologically. The indolyl-imidazolidinic derivative, LPSF / PTS-14, presented greater results than PZQ, 100% death of worms in 24 h at 5 μg / mL, and a toxicity below 5 μg / mL against BALB splenocytes / C mice. These results, combined with low cytotoxicity, stimulated the development of a pharmacophor model using FLAP software, as well as the evaluation of the mode of action by the Michael Addition reaction, and the development of a prediction model for cytotoxicity. The second objective of this work was the accomplishment of a bibliographic study about the PZQ, making it possible to propose a model relating chemical structure and biological activity. Then, in works still under development, a model of pharmacophores will be proposed, and prediction of activity through chemometric methods made. In relation to bacterial infections, the appearance of superbugs, such as the Escherichia coli strain resistant to all antibiotics available in the clinic in 2016, again calls attention to the development of new antibiotics. Aminoglycosides, such as Neamine, are a family of substances of natural or semi-synthetic origin that are effective against Gram (+) and Gram (-) bacteria. The third objective of this work was the synthesis of analogues of Neamine from N- Acetyl-D-glucosamine and the use of metathesis reactions. Although none of the proposed derivatives were synthesized in the allotted time, important advances were made in the proposed routes, and key intermediaries were obtained. It was also possible to develop an evaluation study between the compatibility of protective groups used in derivatives and the occurrence of metathesis reactions. These studies led to the proposition of a synthetic route compatible with the protective groups, initiated at the end of this work, and to be concluded in the future
Xu, Rui. "On the role of the carbohydrate vs the lipid moieties in neoglycolipid self-organisation : Synthesis and liquid crystalline properties of two new families of carbohydrate-based amphiphiles". Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00940381.
Pełny tekst źródłaLindsay, Richard James. "Polymorphic metabolism and the eco-evolutionary influence of social feeding strategies". Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/22745.
Pełny tekst źródłaDayde, Bénédicte. "Développement de phosphasucres inédits pour la synthèse d’analogues de nucléosides à visée antivirale". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2010. http://www.theses.fr/2010ENCM0002.
Pełny tekst źródłaAccording to their wide chemical diversity and their implication in many biological processes, phosphorus compounds are intensively studied by organic chemists. Since 30 years, many phosphorus molecules have been developed and used for their biological properties in medicine or agrochemistry. Chemically and enzymatically stable compounds, phosphonates and phosphoninates are potential derivatives for drug design. Besides, sugars are an important biological family involved in numerous biological pathways which have widely revealed a high therapeutic potential. In this context, the first objective of these works was to develop sugar analogues with an endocyclic phosphorus atom (phosphasugars) to synthesize unpublished families of phosphinosugars and phosphonosugars. Their synthesis were carried out in 4 to 7 steps, using as key reactions : P-alkylation, Pudovik, epoxyde ring-opening reaction, cyclisation by transacetalisation or transesterification. Moreover, these phosphasugars were extended to the synthesis of new nucleoside analogues by introducing nucleobase on phosphasugar moiety. The antiviral activity of these new compounds was evaluated. Finally, a new class of acyclic nucleoside phosphonates was prepared in pyrimidinyl series. Different nucleotide analogues and prodrugs were synthesized in 6-7 steps with uracil, thymine and cytosine and evaluated against HCV and HIV
Massot, Capucine. "Analyse des variations de la teneur en vitamine C dans le fruit de tomate et rôle de l’environnement lumineux". Thesis, Avignon, 2010. http://www.theses.fr/2010AVIG0631/document.
Pełny tekst źródłaFruits and vegetables are the major source of vitamin C in human diet; however, their vitamin C content varies with environmental conditions and agricultural practices. In this work, we successively tested different hypotheses concerning light impact on these variations, using tomato fruit as model. We hypothesized that i) light reaching fruit could have a direct impact on vitamin C metabolism (synthesis, recycling and degradation) or that ii) light reaching leaves could increase the transport of molecules triggering vitamin C accumulation in fruit (sugars, vitamin C…). Our results showed that vitamin C variations with light are complex and depend mostly on light reaching the fruit and to a lesser extent on light reaching leaves,according to fruit developmental stage. The study of vitamin C/sugars relationship in fruit showed that sugars were not determinant in explaining variations in vitamin C. Light impact on vitamin C metabolism were studied, in interaction with temperature, on off-vine fruit ripening. Light increased fruit vitamin C content for temperature lower or equal to 23°C byincreasing transcripts of vitamin C biosynthetic pathway and activity of vitamin C recycling enzyme, particularly at low temperature (12°C). At high temperature (31°C), light did not increase fruit vitamin C content but it decreased DHAR activity and increased threonate content likely produced from vitamin C degradation. The data obtained were used to initiate the building of a model describing vitamin C content during fruit development that will integrate environmental factors in the future
Girard, Emeline. "Etude de la réactivité des cycloheptatriènes silylés : synthèse et fonctionnalisation". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14341/document.
Pełny tekst źródłaThis work sets out to understand the influence of the silyl group at the C7 position on the valence equilibrium and reactivity of the cycloheptatriene (CHT) - norcaradiène (NCD) system, and to use this knowledge to develop new synthetic methodologies. Three new cycloheptatrienes have been synthesized and we have undertaken [3+2] and [4+2] cycloaddition reactions with the aim of desymetrizing them. Although a complete rationale could not be established, this study has highlighted the complex reactivities of silylated CHTs/NCDs. Depending on the nature of the silyl group, 7-membered rings or bicyclic 6-membered rings can be rapidly obtained, and the silyl groups also allow diastereofacial discrimination. The application of the desymetrization reaction of silylated cycloheptatrienes to the synthesis of sugar mimics constitutes a major aspect of this work. Dihydroxylation of silylated CHTs has afforded diols which could be functionalized into three novel aminoheptitols. Endoperoxides from photooxygenation have been desymmetrized by an asymmetric Kornblum-DeLaMare reaction, and a study of possible further functionalization (notably by radical processes) has also been carried out
Gatineau, Eva. "Impact d'un régime riche en saccharose sur la sarcopénie chez le rat âgé ; Conséqences métaboliques au niveau hépatique et cérébral. Effets préventifs d'un mélange de micronutriments. Spécialité". Thesis, Clermont-Ferrand 1, 2015. http://www.theses.fr/2015CLF1MM14/document.
Pełny tekst źródłaWith aging, several alterations occur, including a loss of muscle mass and function, called sarcopenia. Many factors are responsible for the development of sarcopenia, but some factors as inflammation, oxidative stress and insulin resistance, which have many deleterious effects during aging, can reduce meal-induced stimulation of muscle protein synthesis which was shown to partly explain age-related muscle mass loss. Those factors can be induced by a diet rich in added sugar, characteristic of current dietary habits. Although this kind of diet could accelerate aging features, little is known about combined effect of aging and high sugar diet, particularly on sarcopenia. Thus, the purpose of this work was to determine whether high chronic intake of added sugars could accelerate sarcopenia. We also interested in the combined effect of added sugars and aging on other exposed tissues: liver and brain. Finally, we assessed the preventive effects of a micronutrient supplementation both in vivo and in vitro.In order to do that, for 5 months, 16 month old rats were starch fed or sucrose fed (62% sucrose), with or without micronutrients supplementation (rutin, vitamin A, vitamin E, vitamin D, selenium and zinc). Additionally, an adult control group of 8 month old rats was included. Besides, anti-inflammatory effects of micronutrients were tested in vitro.We showed that high sucrose diet accelerated age-related muscle mass loss by impairing postprandial protein synthesis, likely through decreased insulin sensitivity since inflammation and oxidative stress were only slightly affected by high sucrose diet. This diet also resulted in fat mass gain and increased plasma and liver triglycerides, by modulating the activity of enzymes involved in liver lipid metabolism. In the brain, high sucrose consumption led to decreased protein concentration independently of protein synthesis alteration. Micronutrients supplementation only partially reversed high sucrose diet effects: it did not act on lean body mass but prevented fat mass gain, by inhibiting hepatic lipogenesis. It also restored brain protein synthesis, which was reduced by aging. In vitro, it reduced experimentally induced inflammation.Thus, this work showed that a high sucrose diet accelerates sarcopenia in old rats but also induces liver and brain alterations. Prevention by micronutrients remained limited
Zhao, Yi. "Degradable molecularly imprinted polymers-synthetic antibody mimics for the vectorization of active molecules". Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2189.
Pełny tekst źródłaMolecularly imprinted polymers (MIPs) are biomimetic synthetic receptors that possess two of the most important features of biological antibodies – the ability to recognize and bind specific target molecules. Owing to their easier preparation, lower cost, higher specifity and stability compared to antibodies, they have the potential to be widely applied for environemental and food analysis. Recently, MIPs also emerged in the biochemical field as diagnostic tools, chemicals traps to remove undesirable substance from the body, or drug delivery systems, where usually the combination of biocompatibility and degradability after its use is desirable. Here, we developed biochemically or enzymatically degradable MIPs, which have potential applications as activation-modulated drug delivery systems. In general, MIPs are prepared by radical polymerization of functional monomers and cross-linkers in the presence of a target molecule acting as template. Degradable MIPs were synthesized using cleavable cross-linkers containing a degradable group (disulfide bond or phosphate ester bond) or derived from a natural disaccharide. In the presence of a cleaving reagent (reducing agent or enzyme), the chemo or enzyme-sensitive bond could be cleaved, resulting in the degradation of the polymer matrix. The degraded polymers looses the binding sites structure resulting in the loss of recognition and binding capacity towards the target molecules, and thus in the release of bound molecules. These degradable MIPs provide new opportunities as “smart” vectors for controlled delivery of active molecules in biomedical applications. Finally, the biodegradation of the polymer backbone by bacteria was investigated
Ziegler, Véronique. "La rhizomanie, une maladie virale de la betterave a sucre : contribution a l'etude du mecanisme d'expression et des proprietes biologiques du genome du virus des nervures jaunes et necrotiques de la betterave". Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13017.
Pełny tekst źródłaFilipe, Luís. "New Methods for the Synthesis of Phenypropanoic Sucrose Esters". Master's thesis, 2019. http://hdl.handle.net/10362/88070.
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