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Freestone, Primrose P. E. "The L-serine dehydratase from Escherichia coli." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/35225.
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The discovery that the L-serine dehydratase (E.C. 4.2.1.13) from Escherichia coli B could be stabilised by iron and dithiothreitol has allowed this enzyme to be purified to a level approaching homogeneity. The purification scheme involved chemical treatments with streptomycin sulphate and ammonium sulphate, and elution from DEAE cellulose, pentyl agarose. Mono Q, Reactive Green and Phenyl superose chromatography columns. The purified dehydratase had a specific activity of 1653 ?moles of pyruvate min-l mg-1 enzyme and was, as judged by SDS PAGE, about 90 % pure. Overall recoveries were in the region of 4 % of the starting activity. A series of spectroscopic investigations and inhibitor studies showed that L- serine dehydratase did not utilise pyridoxal phosphate as cofactor. However, the purified enzyme did show an absolute requirement for iron and dithiothreitol for activity. The activation produced by these reagents was characterised and found to be slow, markedly influenced by both temperature and pH, and could be prevented, or reversed, by metal chelators, such as EDTA and o-phenanthroline. The activation process was also oxygen-dependent, and appeared to involve the production of an oxygen radical, since it was subject to inhibition by catalase and stimulation by hydrogen peroxide. Activation of L-serine dehydratase by iron and DTT also appeared to involve iron binding, at a ratio of 2 - 3 ?moles of Fe per ?mole enzyme. However, UV/visible and EPR investigations were unable to identify the structural form in which this bound iron existed. L-Serine dehydratase was found to be specific for L-serine; D-serine, L-threonine and L-cysteine were not deaminated. The timecourse of pyruvate formation was found to be non-linear, and the substrate saturation curve for L-serine sigmoidal, with an S[0.5] value of 2.6 mM, and a Hill coefficient of 2.13. The dehydratase could be activated by its substrate, L-serine, or substrate analogue, D-serine, which resulted in the production of a linear timecourse and hyperbolic substrate saturation profile (S[0.5] 2.8 mM, Hill coefficient 1.13). The molecular basis of this substrate activation process was investigated, and appeared to have its origins in a slow, serine-dependent rearrangement of the tertiary structure of the enzyme rather, than had previously been suggested from studies of the dehdyratase in crude extracts, a dimerisation reaction. In common with other microbial L-serine dehydratases, the purified E. coli B enzyme showed a broad pH optimum for pyruvate production, with maximal activity occurring between pH 7.8 and 8.2. It was inhibited competitively by L-cysteine and D-serine, with Ki values of 1.6 and 4.2 mM, respectively, and irreversibly by sulphydryl-active agents such as DTNB, N-ethylmaleimide and HgC12. In addition, the N-terminal amino acid sequence of the E. coli B L-serine dehydratase was analysed, and was found to show a high level of similarity with the predicted N-terminal sequence of the L-serine dehydratase from E. coli K12.
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Nozaki, Hiroyuki. "Studies on the enzymatic synthesis of α-methyl-L-serine." Kyoto University, 2009. http://hdl.handle.net/2433/124025.
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Ferreira, Graziele Cristina. "Purificação e caracterização de um inibidor de elastase de neutrófilos do feijão-caupi (Vigna unguiculata L Walp)." reponame:Repositório Institucional da UFABC, 2017.
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Orientador: Prof. Dr. Sergio Daishi SasakiDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, 2017.
O Feijão Caupi (Vigna unguiculata (L.) Walp) é uma leguminosa com importante representatividade econômica e nutricional, especialmente no Brasil. Inibidores de serino proteases, como a tripsina, já foram descritos na espécie, assim como em outras plantas. No entanto, nesta espécie, ainda não foram identificados inibidores que apresentem atividade sobre a elastase de neutrófilos humana (HNE), protease envolvida em muitos processos patológicos, como na instalação e progressão da doença pulmonar obstrutiva crônica (DPOC). Nesse estudo, purificamos um inibidor a partir do extrato protéico de Vigna unguiculata que apresenta atividade sobre HNE. Inicialmente, foi realizado o processo de extração alcalina de proteínas, seguido de três passos cromatográficos distintos, utilizando as colunas Hitrap-Q (Troca-iônica), Source15RPC (Fase-Reversa) e ACE18 (Fase-Reversa). Essas etapas foram acompanhadas por testes de atividade inibitória, utilizando os substratos fluorogênicos Meo-Suc-Ala-Ala-Pro-Val-MCA (Elastase) e Z-Phe-Arg-MCA (Tripsina), além de ensaios da quantificação de concentração total de proteínas. Para determinar a massa do inibidor, foram utilizadas as técnicas de espectrometria de massa por MALDI-TOF e SDS-PAGE, o inibidor apresenta massa molecular de 10,99 KDa. O Ki para HNE foi determinado no valor de 9 pM. O inibidor não apresentou atividade inibitória sobre tripsina e trombina, porém foi observada atividade sobre subtilisina e quimotripsina. Estes dados indicam que o inibidor purificado trata-se de uma molécula ainda não caracterizada, devido às suas atividades inibitórias o nomeamos de Vigna unguiculata Elastase Inhibitor (VuEI).
The cowpea (Vigna unguiculata (L.) Walp) is a legume of important economic and nutritional representativeness, especially in Brazil. Serine protease inhibitors, such as trypsin, have been described in many species, as well as in other plants. In this specie an inhibitor with activity on human neutrophil elastase (HNE) has not yet been identified. This protease is involved in many pathological processes, such as the onset and progression of chronic obstructive pulmonary disease (COPD). We purified and characterized an inhibitor from the protein extract of Vigna unguiculata presenting activity towards HNE. Firstly, we performed the alkaline extraction procedure for proteins followed by three different chromatographic steps using Hitrap Q (ion exchange), Source15RPC (Reversed-Phase) and ACE18 (Reversed Phase) columns. These steps were followed by the inhibitory activity tests using fluorogenic substrates, MeO-Suc-Ala-Ala-Pro-Val-MCA (elastase) and Z-Phe-Arg-MCA (trypsin), and quantitation assays of protein concentration. To determinate the size of the molecule, we used MALDI-TOF mass spectrometry and SDS-PAGE. The molecular mass of the inhibitor was 10,99 kDa. The dissociation constant (Ki) toward HNE was 9 pM. HNE inhibitor showed no inhibitory activities toward trypsin and thrombin. However, the inhibitor presented activity toward subtilisin and chymotrypsin. These datas indicate that this molecule is a novel inhibitor to HNE and we named it Vigna unguiculata Elastase Inhibitor (VuEI).
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Kennedy, Victoria Angela. "Optimization of L-serine crystallization using methanol as an anti-solvent." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/11261.
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Burman, Julia Dawn. "Structural and functional analysis of enzymes implicated in the fermentation of L-serine and L-threonine." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410126.
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Luk, Chee-wei Jennifer. "Solubility and Pseudo-polymorphic Transitions of L-Serine in Water-Methanol System." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6832.
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The research addressed in this thesis is focused on the solubility and pseudo-polymorphic transition of L-serine in mixed water-methanol systems. Cooling re-crystallizations were carried out that varied both temperature and methanol concentration. Solubilities were measured with high-performance liquid chromatography. It is found that the solubility increased with increase in temperature and decreased drastically with methanol concentration. The effect of temperature at which there is a transition of L-serine crystals from the rod-shaped (anhydrous) form to hexagonal (monohydrate) form was confirmed and that transition temperatures decreased with methanol concentrations in a non-linear manner. The solubility data were correlated and plotted using the vant Hoff equation and the enthalpy and entropy of dissolution were determined. These values increased with increase in methanol concentration. The solid crystals were analyzed by optical microscopy and powder X-ray diffraction. The rod-shaped crystals were identified to be anhydrous L-serine, while the hexagonal crystals were L-serine monohydrate. Dehydration of the monohydrated crystals in their solid-state was examined and the onset of such phenomenon was known to start once the crystals were removed from the solutions.
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Zhang, Han. "Profiling L-serine Transport Throughout Growth and Meiotic Maturation in Mouse Oocytes." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39247.
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With the increasing demand for assisted reproduction, more knowledge and understanding towards health requirements of oocytes and their inner workings are required. With current IVF success rates of approximately 40%, oocyte and embryo culture conditions in vitro can be improved by first understanding the finer details of oocyte function. As such, there is a need to better understand the mechanisms through which oocytes can acquire certain nutrients. This thesis focuses on the amino acid serine, which has been shown to improve outcome in developing embryos and also plays a variety of roles in the body that may carry over to oocyte health as well. Using radiolabeled [3H] serine, we measured uptake of serine as a function of time throughout growth and meiotic maturation in mouse oocytes. Serine transport appeared in oocytes during growth and became absent in mature eggs. With a competition assay using substrates diagnostic for several different amino acid transporter systems and culture with and without sodium in the external medium, I identified Na+-dependent SNAT7 of the System A/N (SLC38) family to be the most likely transporter in oocytes. Quantitative RT-PCR was consistent with this result. Transporter activity is also not activated by progression of meiotic maturation, as indicated by unperturbed transport when dbcAMP was provided to maintain meiotic arrest. However, a biological regulator of arrest, NPPC, resulted in enhanced transport activity in vitro. This may be due to signalling mechanisms of the NPPC pathway affecting regulation of serine uptake, which presents a direction for future research.
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Lan, Jie. "Escherichia coli mutants unable to use a combination of L-serine, glycine and L-leucine as carbon source." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39951.pdf.
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Guay, Caroline. "Expression et rôle d'une nouvelle protéase à sérine: l'«eosinophil serine protease»-1." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24677/24677.pdf.
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Lee, Johnny Chien-Yi Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Transcriptional and metabolic responses of yeast Saccharomyces cerevisiae to the addition of L-serine." Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/41012.
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Sudden changes in nutrient resources are common in the natural environment. Cells are able to adapt and propagate under changing environmental conditions by making adjustments in their cellular processes. These cellular adaptations involve genome-wide transcriptional reprogramming that results in the induction or repression of metabolic pathways. Specific enzymes are then synthesised and activated to maximise the use of the newly available nutrient sources. L-serine is one of the twenty proteinogenic amino acids, and can be synthesised in yeast by the glycolytic and gluconeogenic pathways when growing on fermentable or non-fermentable carbon sources or taken up from the environment when available. L-serine is metabolically linked to glycine and is a predominant donor of one-carbon units in one-carbon metabolism. L-serine is also a source of pyruvate and ammonia and contributes to other cellular processes including the biosynthesis of cysteine and phospholipids. Previous work has shown that yeast cells exhibit transcriptional induction of the one-carbon pathway and the genes involved in the synthesis of purine and methionine after the addition of 10 mM glycine. Here it is shown that addition of 10 mM L-serine did not, however, elicit the same transcriptional response. This is primarily due to differences in the uptake of glycine and L-serine in yeast. High concentrations of extracellular L-serine were required for yeast to show an increase in intracellular L-serine concentration of the magnitude required to trigger a noticeable cellular response. Despite L-serine and glycine being interconvertable via the SHMT isozymes and being a one-carbon donor, the genome-wide transcriptional response exhibited by cells in response to L-serine addition was markedly different to that seen for glycine. The predominant response to an increase in intracellular L-serine was the induction of the general amino acid control system and the CHA1 gene encoding the serine (threonine) dehydratase. Unlike glycine, addition of L-serine triggered only minor induction of the one-carbon pathway. A large portion of intracellular L-serine was converted to pyruvate and ammonia in the mitochondrion as the result of induction of CHA1. The high intracellular concentration of L-serine stimulated the cell to increase the production of oxaloacetate and to increase the biosynthesis of L-aspartate. Transient increases in the intracellular L-glutamate and L-glutamine were also observed after the addition of L-serine. The work presented in this study shows that large increase in the intracellular concentration of amino acid is required to trigger a significant transcriptional response. Yeast cells exhibit different transcriptional and metabolic responses to the addition of L-serine and glycine even though these two amino acids are closely metabolically linked. Addition of L-serine provokes the GAAC response, expression of the CHA1 gene and stimulates the biosynthesis of L-aspartate in yeast whereas addition of glycine induces the one-carbon pathway which leads to the biosynthesis of the purine nucleotides.
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Vasconcelos, Leonardo de. "Síntese de um fragmento precursor do fármaco Indinavir." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-23042013-141617/.
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Neste trabalho foram aprofundados nossos estudos para obtenção da (S)-2-terc-butilamida-4-(3-picolil)piperazina, pela abertura da (S)-2-terc-butilcarboxamida-N-p-tosilaziridina seguida de ciclização, em 78% de rendimento, com o triflato de vinildifenilsulfônio. A aziridina foi preparada por um processo de ciclização, em condições de transferência de fase, partindo-se da L-serina, um aminoácido natural de baixo custo. Esta rota sintética rendeu um material que apresenta a mesma estereoquímica S do fragmento piperazínico usado na síntese do Indinavir, podendo vir a constituir uma via alternativa para a obtenção deste fármaco.In this work we performed a deeper study for obtaining (S)-2-tert-butylamide-4-(3-picolyl)piperazine by opening (S)-2-tert-butylcarboxamide-N-p-tosylaziridine followed by cyclization, in 78% yield, with diphenylvinylsulfonium trifluoromethanesulfonate. The aziridine were prepared by a cyclization process in phase transfer conditions, starting from L-serine, a low cost amino acid. This synthetic route yielded a material which has the same S piperazinic fragment stereochemistry used in the synthesis of Indinavir, and may constitute an alternative route for obtaining this drug.
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Vigneron, Pierre-Antoine. "Le métabolisme astrocytaire de la L-sérine et ses implications dans la maladie d'Alzheimer : une potentielle approche thérapeutique lmpairment of Glycolysis-Derived L-Serine Production in Astrocytes Contributes to Cognitive Deficits in Alzheimer's Disease L-Serine Links Metabolism with Neurotransmission." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL016.
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Les pertes de mémoire et les changements comportementaux sont les premiers signes de la maladie d’Alzheimer (MA). Les patients présentent souvent un métabolisme du glucose diminué, observable par TEP 18F-fluorodéoxyglucose. L’implication de cette perturbation du métabolisme du glucose dans la pathogenèse de la MA n’est pas connue. Dans le cerveau, le glucose est oxydé pour produire l’ATP nécessaire à l’activité synaptique. Cependant, des observations récentes suggèrent qu’une altération de la glycolyse aérobie sur-vient de façon précoce dans la MA. Le phosphorylated pathway dévie le 3-phosphoglycérate du flux glycolytique pour la production de novo de L-sérine, via trois enzymes (PHGDH, PSAT1, PSPH). Les astrocytes sont la principale source de L-sérine dans le cerveau. Nous émettons l’hypothèse qu’une perturbation de la production astrocytaire de L-sérine, due à l’altération du métabolisme énergétique, puisse participer à l’établissement des déficits observés dans la MA. Nous avons utilisé le modèle murin 3xTg-AD, récapitulant les déficits métaboliques et synaptiques en plus des pathologies tau et amyloïde de la MA. Nous avons mis en évidence une diminution de la concentration en L-sérine dans l’hippocampe de ces souris. En conséquence, nous les avons nourries avec un régime enrichi à 10% en L-sérine pendant deux mois, ayant pour résultat d’améliorer leurs déficits synaptique et cognitif. Dans le but de comprendre les mécanismes sous-jacents à cet effet bénéfique de la L-sérine, nous nous sommes intéressés au métabolisme des lipides. Par analyse 3D de la morphologie cellulaire, nous avons mis en évidence une diminution du territoire couvert par les astrocytes de ces souris, déficit pouvant être amélioré par le régime L-sérine. Pour identifier l’impact de cette diminution sur la neurotransmission, nous avons évalué la couverture astrocytaire des synapses de l’hippocampe par microscopie électronique. Ensemble, ces résultats suggèrent un rôle critique de la L-sérine astrocytaire dans la plasticité synaptique et la mémoireSubtle losses of memory or changes in behavior are the first outward signs of Alzheimer’s disease (AD). AD patients often display concomitant reduced glucose metabolism as observed by 18F- fluorodeoxyglucose PET. Whether such energy metabolism deficit contributes to cognitive impairment in AD is still not known. In the brain, oxidative use of glucose provides most of the ATP required to fuel synaptic activity. However, recent observations suggest that changes in aerobic glycolysis prevail in the early phase of AD. The phosphorylated pathway diverts 3-phosphoglycerate from the glycolytic flux, to produce de novo L-serine through the action of three enzymes (PHDGH, PSAT1 and PSPH). Astrocytes are the main source of L-serine in the brain. We made the hypothesis that a dysfunction in astrocyte L-serine production, resulting from an altered ener-gy metabolism, could participate in the deficits observed in AD. We used 3xTg-AD mice, a mouse model that recapitulates metabolic and synaptic deficits in addition to classical AD hallmarks. We measured the level of L-serine in the hippocampus of these mice and found it was decreased compared to controls. Consequently, we supplemented them with a 10%-L-serine-enriched diet during 2 months which rescued their synaptic and cognitive deficits. To unveil the mechanisms underlying such beneficial effects of L-serine we focused on its participation in lipid synthesis. We analyzed cell morphology using 3D-reconstruction and found neuron morphology was not altered but the territory covered by astrocytes is decreased and can be fully restored by L-serine diet. To further identify the impact of this diminution on neurotransmission we assessed the astrocytic coverage of hippocampal synapses, using electron microscopy. Together, these results suggest a critical role for astrocyte L-serine in synaptic plasticity and memory
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Chronis, Demosthenis. "Sulfur metabolism in Glycine max [L.] Merr characterization of serine acetyletransferase and O-acetylserine (thiol) lyase /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4483.
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Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 1, 2009) Vita. Includes bibliographical references.
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MEYER, FRANCK. "Synthese et applications d'acides [alpha]-amines [beta]-halogenes et [beta]-phosphores derives de la l-serine." Cergy-Pontoise, 2000. http://www.theses.fr/2000CERG0104.
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Le travail presente dans ce memoire concerne une nouvelle synthese d'acides amines -halogenes et -phosphores a partir d'oxazolines derivees de la l-serine. L'etape cle de cette synthese reside dans l'ouverture de l'oxazoline au niveau de la liaison c(5)-o par action d'un halogenure de trimethylsilyle. Les -halogenoamidoesters prepares sont transformes ensuite en sels de phosphonium, par quaternisation avec la triphenylphosphine, avec des rendements atteignant 98%. La purete enantiomerique des composes a ete determinee soit par hplc sur colonne chirale, soit par rmn 3 1p en presence d'un anion chiral. La saponification de l'oxazoline ester donne un sel qui reagit egalement avec des halogenures de trimethylsilyle pour donner les derives -halogenoamidoacides correspondants, porteurs d'une fonction acide carboxylique libre. Apres quaternisation avec la triphenylphosphine, les sels de -phosphonium amidoacides libres sont obtenus avec des rendements atteignant 95%. Dans ce cas, l'exces enantiomerique a ete determine soit par rmn 3 1p, soit par utilisation de l'anion chiral -binphat, soit par formation d'un sel avec un alcaloide. L'utilisation des sels de phosphonium prepares comme reactifs de wittig pour l'hemisynthese d'acides amines par creation d'une double liaison carbone-carbone sur la chaine laterale, a ete etudiee. Si la reactivite observee est encore modeste, les resultats obtenus pour la construction d'acides amines ,-insatures sont comparables a ceux de la litterature. L'oxazoline derivee de la serine reagit egalement avec les phosphites pour donner apres ouverture de l'heterocycle les derives -phosphonates d'aminoesters. Toutefois, dans ces conditions les -phosphonates sont obtenus sans activite optique.
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McClure, G. David (George David). "A Study of the Intrinsic Fluorescence of O-Acetyl-L-Serine Sulfhydrylase-A from Salmonella typhimurium." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc278975/.
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O-Acetyl-L-serine sulfhydrylase-A (OASS-A) forms acetate and L-cysteine from O-acetyl-L-serine (OAS) and sulfide. One molecule of the cofactor pyridoxal 5'- phosphate (PLP) is bound in each holoenzyme protomer.
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Kasparova, Pavla. "Doppelthydrophile Blockcopolymere als Mineralisationstemplate." Phd thesis, Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2005/46/.
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Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA′s) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt.Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln.
This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate.
Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator.
The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering measurements (WAXS) were used to prove the modification of Calcium Carbonate particles and to calculate the size of Calcium Carbonate and Barium Sulfate nanoparticles.
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Hatchell, Hayley. "The relationship between docohexanoic acid (DHA) and L-serine, providing an insight into the biochemistry of meningioma." Thesis, University of Central Lancashire, 2017. http://clok.uclan.ac.uk/23985/.
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As far back as the 1920s, Otto Warburg observed that cancerous cells display an altered state of metabolism surrounding lipid biosynthesis. However, only until recently has metabolic reprogramming been a recognised hallmark of the disease. The number of cancer cases diagnosed is set to triple by 2030, demonstrating the need for disease prevention, improved diagnostic testing and personalised treatment therapies. However, with some cancers occurring in the brain and spinal cord, the type of treatment available can become challenging due to their locality. Such cancer types include meningioma and glioma which are the most common brain tumours diagnosed. An initial study involving human meningioma tissue revealed unusually high levels of the phosphatidylserine enriched with docosahexaenoic acid (DHA). In this study, the metabolism surrounding lipid biosynthesis was examined to establish if such alterations in lipid profiles were related to an altered state of metabolism. From the results gained, it can be suggested that meningioma does have an altered state of metabolism, evolving around serine as opposed to DHA. From the grade I and grade II meningioma tissues immunochemically examined, positive expressions of pyruvate kinase isoform 2 (PKM2) and phosphoglycerate dehydrogenase (PHGDH) were shown. Therefore, the results demonstrated that within meningioma tissues, serine can allosterically regulate the flux through glycolysis. The association that serine presence alone can alter the metabolic flux was demonstrated in the model organism, Lipomyces starkeyi. Those L. starkeyi cells supplemented with serine, displayed a 50% reduction in the amount of radiolabelled acetate taken up during exponential and stationary growth phases. The radiolabelled study also highlighted that with serine presence, de novo lipid biosynthesis was altered. Once synthesised, these neutral lipids go on to be 4 stored in membrane bound organelles. Within the phenotype of cancerous cells, such storage of neutral lipids into lipid droplets prevent lipotoxicity. The light microscopy study of L. starkeyi cells supplemented with serine demonstrated that the formation of such lipid droplets was enhanced during lipid accumulation. These findings suggest that the production, storage and mobilisation of lipids within serine supplemented cells are adapted to cellular requirements, promoting a cancerous phenotype. In order to gain an insight into the potential impact that an altered metabolic state may give to meningioma, a liposomal study was developed. Supplementation of both phosphatidylserine-consisting liposomes, as well as tumour-derived liposomes, enhanced the cellular viability of the non-cancerous cell line, SVG, during exponential phase. The supplementation of meningioma-derived liposomes also increased the viability of the non-cancerous human fetal glial SVG cell line, similar to that observed with phosphatidylserine containing liposomal preparations. Therefore, the data suggest that in fact, the phospholipid (phosphatidylserine), rather than the fatty acid (DHA) plays a role in cellular viability. It is concluded that the results gained from this study can be used clinically in the diagnosis and management of meningioma as well as other diseased cells displaying ectopic lipid accumulation. The observation that meningioma has an altered biochemistry may provide guidance when histologically grading meningioma tumours. For those tumours expressing the enzymes involved in serine biosynthesis, such as PKM2 and PHGDH, a targeted treatment therapy surrounding enzyme inhibitors can be examined. By targeting serine biosynthesis, the resources needed to enable a cancerous phenotype are depleted. Future research can examine such targeted therapies utilizing either the developed model organism, L. starkeyi or the conventional SVG and U87 cell lines.
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Charmolue, Herve. "The effects of process variables on purity, size, and habit of L-serine crystals recovered by batch crystallization." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/11163.
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Gatewood, Marena Dessette. "Solubility and recovery of L-isoleucine from high pH solutions and the cause for L-serine habit differences when crystallized from water and methanol/water solutions." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/10916.
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Shelton, Thomas Earl. "Small Phosphomonoesters as Probes of Protein-Tyrosine Phosphatase Active Sites." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/44898.
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I evaluated the potential of isomers of the low molecular weight phosphomonoester naphthyl phosphate as general diagnostic substrates for differentiating between two families of protein phosphatases: the protein-tyrosine phosphatases [PTPs] and the dual-specificity protein phosphatases [DSPs]. Three PTPs, PTP-1B, Tc-PTPa, and PTP-H1, and three DSPs, Cdc-14, VHR, and IphP, were challenged in vitro with alpha-naphthyl phosphate and beta-naphthyl phosphate. Both the DSPs and PTPs readily hydrolyzed beta-naphthyl phosphate. As expected, the DSPs also hydrolyzed alpha-naphthyl phosphate at rates comparable to beta-naphthyl phosphate and two of the PTPs, PTP-1B and Tc-PTPa, hydrolyzed alpha-naphthyl phosphate at a rate one-tenth that of beta-naphthyl phosphate. However, PTP-H1 hydrolyzed both alpha- and beta- naphthyl phosphate at nearly equal rates. Intriguingly, when challenged with radiolabeled phosphoproteins, PTP-H1 was markedly less stringent, by a factor of 40- to 200- fold, than PTP-1B or Tc-PTPa in its selectivity for [32P]phosphotyrosyl- over [32P]phosphoseryl- proteins in vitro.
The DSPs and PTPs listed above also were challenged in vitro with free phosphoserine. Each displayed little or no activity towards free phosphoserine. However, the addition of a hydrophobic "handle" to form N-(cyclohexane carboxyl)-O-phospho-L-serine produced a derivative that was hydrolyzed by IphP at rates comparable to that of the avid substrates p-nitrophenyl phosphate and beta-naphthyl phosphate. VHR also hydrolyzed N-(cyclohexane carboxyl)-O-phospho-L-serine, though at a lower rate than IphP. Cdc14 displayed little activity towards N-(cyclohexane carboxyl)-O-phospho-L-serine.
The active site of VHR was mapped and amino acid residues potentially involved in binding N-(cyclohexane carboxyl)-O-phospho-L-serine were identified. The amino acid sequence of VHR was aligned with the amino acid sequences of IphP and Cdc14 to identify the nature of the corresponding residues in IphP and Cdcd14.
Low molecular weight phosphomonoesters have proven to be effective in vitro indicators of protein phosphatase activity. They also have shown potential as diagnostic substrates for specific subclasses of protein phosphatases. However, neither alpha- and beta- naphthyl phosphate nor N-(cyclohexane carboxyl)-O-phospho-L-serine proved to be universal discriminatory substrates for the functional subgroups within the family of protein-tyrosine phosphatases. Indeed, the probability of identifying such a substrate would appear to be relatively low.
Master of Science
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Maugard, Marianne. "Rôle de la sérine astrocytaire dans l'apprentissage et la mémoire et ses implications dans la maladie d'Alzheimer." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS166/document.
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La perte de mémoire est un des premiers symptômes caractéristiques de la maladie d’Alzheimer (MA). Dans les cerveaux des patients, on retrouve des dépôts extracellulaires de plaques amyloïdes ainsi que des agrégats intracellulaires de la protéine tau. Les patients présentent également des déficits du métabolisme cérébral du glucose, une quinzaine d’années avant les premiers défauts cognitifs, suggérant que le métabolisme pourrait contribuer à la physiopathologie de la MA. Pour mieux comprendre les mécanismes qui relient le métabolisme énergétique et l’activité synaptique, nous nous sommes intéressés à la production de L-serine, une molécule dont la synthèse de novo dérive d’un intermédiaire de la glycolyse. La L-serine est le précurseur de la D-sérine, un acide aminé en conformation D présent en grande quantité dans le cerveau. La D-sérine est un co-agoniste des récepteurs au N-méthyl-D-aspartate (NMDA-R) nécessaire à la potentialisation à long terme (LTP) de l’activité synaptique dans l’hippocampe. La voie de biosynthèse de la L-serine est ainsi à l’interface entre métabolisme énergétique et activité synaptique. Afin d’étudier le rôle de cette voie, nous avons mis au point un modèle de délétion conditionnelle de la Phgdh, la première enzyme de la voie de biosynthèse de la L-serine. Nous avons injecté par stéréotaxie des vecteurs adéno-associés permettant l’expression de la Cre recombinase dans l’hippocampe de souris Phgdh(flox/flox), une lignée de souris qui possède des sites LoxP autour des exons 4 et 5 du gène de la Phgdh. Nous avons validé ce modèle en montrant que l’expression de Phgdh ainsi que les taux de D-serine diminuent d’environ 60% dans l’hippocampe des souris injectées. Nous avons ensuite réalisé des enregistrements électrophysiologiques sur tranches et nous avons mis en évidence une diminution de la LTP dans l’hippocampe des souris injectées avec la Cre recombinase. Ces souris présentent également un déficit de mémoire à long terme mis en évidence avec le test de la piscine de Morris. Ces déficits sont restaurés lorsque les souris reçoivent chroniquement un régime enrichi en L-serine. Ces résultats montrent que la biosynthèse de sérine est nécessaire et suffisante pour la plasticité synaptique et la mémoire à long terme.Afin d’étudier le rôle de cette voie dans la MA, nous avons mesuré l’expression de différentes enzymes dans des extraits d’hippocampes de patients atteints de MA et nous avons mis en évidence des changements significatifs dès les stades intermédiaires. Finalement, nous avons étudié un modèle murin de MA, les souris 3xTg, qui présentent des déficits métaboliques, synaptiques et comportementaux. Les déficits de LTP sont restaurés en ajoutant de la L- ou de la D-sérine de façon aigue sur les tranches d’hippocampe. Nous montrons que le déficit de mémoire spatiale à long terme peut être restauré par une supplémentation chronique en D-sérine, suggérant l’importance de cette voie dans le contexte de la MAMemory loss is among the first symptoms reported by patients suffering from Alzheimer’s disease (AD). AD is characterized by extracellular amyloid plaques and intracellular aggregations of tau. A decrease of brain glucose metabolism has also been described in the brain of AD patients. Since this decrease appears decades before memory loss, we hypothesize that metabolic deficits could directly contribute to AD physiopathology. To understand the mechanisms linking brain metabolism and synaptic activity, we proposed to study the production of L-serine, a signaling molecule whose de novo synthesis diverts part of the glycolytic flux. L-serine is the precursor of D-serine, a co-agonist of N-methyl-D-aspartate receptors (NMDA-R) that is required to maintain long term potentiation (LTP) of synaptic activity in the hippocampus. Since both L- and D-serine are formed through the activity of the Phosphorylated Pathway that diverts part of the glycolytic flux, any metabolic deficits may impact synaptic activity.We developed a model of conditional Phgdh deletion, the first enzyme of the phosphorylated pathway, by stereotaxically injecting Adeno-Associated Vectors allowing the expression of Cre recombinase in the hippocampus of Phgdh(flox/flox) mice, a mice strain with loxP sites flanking exons 4 and 5 of Phgdh gene. We validated this model showing that Phgdh expression and D-serine level are decreased by 60% in the hippocampus of injected mice. We performed electrophysiological recordings and showed that LTP is significantly reduced in mice injected with Cre recombinase. Those mice also show long term memory deficits in the Morris Water Maze test. Those deficits are restored by chronically feeding Cre injected mice with a diet enriched in L-serine indicating that serine biosynthesis is necessary and sufficient for synaptic plasticity and long term memory.To assess whether this pathway may be involved in AD pathogenesis, we quantified the expression of several enzymes of the serine biosynthesis pathway in human brain samples and found major changes in AD patients even at intermediate stages. To further investigate this hypothesis, we used 3xTg-AD mice, a mouse model for AD showing deficits in brain metabolism, synaptic activity and cognition. LTP deficits in 3xTg mice are restored by acute supplementation of L- or D-serine on hippocampal slices. We show that chronic administration of D-serine restores long term spatial memory. It suggests that serine biosynthesis is an important pathway in AD
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Annor-Gyamfi, Joel K. "Synthesis, Characterization and Biological Evaluation of Pyrrolo[2,1-c][1,4]benzodiazepines for Cytotoxicity and Serine β-lactamases Inhibition." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3085.
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Pyrrolo[2,1-c][1,4]benzodiazepine (PBD) derivatives possess cancerostatic and anti-infective properties thus making them candidates of possible antibacterial agents. ²-lactam antibiotics are vital weapons for the treatment of bacterial infections, but their existence and effectiveness has been faced with resistance from ²-lactamases. Therefore, the need for new effective antimicrobial drugs is very crucial. In this work, we synthesized in high yields, PBD analogs 1−3, 5 and 7−9 in three to four synthetic steps from commercially available L-proline and isatoic anhydride. MTT Assay was employed to test the in vitro cytotoxicity of PBD analogs 1, 2, 5 and 7 on cancer cell lines including MCF-7, SKBR-3, SKMEL-2, CaCo 2 and Mia Paca. These compounds decreased the cell viability of MCF-7 by roughly 20% however, 1 and 5 had no effect on the SKMEL-2 cell lines. The inhibitory efficacy of these PBDs were also tested against TEM-1 and P99 Serine class A and C ²-lactamases.
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Romagnoli, Barbara. "Synthesis and characterisation of a novel class of chiral poly(aromatic aminde) dendrimers incorporating a C₃-symmetric core system derived from the α-amino acids L- and D-serine." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250671.
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Stolz, Michael. "Untersuchungen zur L-Serin-Bildung mit Corynebacterium glutamicum." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982789254.
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Barnard, Sandra H. "Amalgamation of Nucleosides and Amino Acids in Antibiotic Biosynthesis." UKnowledge, 2013. http://uknowledge.uky.edu/pharmacy_etds/20.
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The rapid increase in antibiotic resistance demands the identification of novel antibiotics with novel targets. One potential antibacterial target is the biosynthesis of peptidoglycan cell wall, which is both ubiquitous and necessary for bacterial survival. Both the caprazamycin-related compounds A-90289 and muraminomicin, as well as the capuramycin-related compounds A-503083 and A-102395 are potent inhibitors of the translocase I enzyme, one of the key enzymes required for cell wall biosynthesis. The caprazamycin-related compounds contain a core nonproteinogen b-hydroxy-a-amino acid referred to as 5’-C-glycyluridine (GlyU). Residing within the biosynthetic gene clusters of the aforementioned compounds is a shared open reading frame which encodes a putative serine hydroxymethyltransferase (SHMT). The revelation of this shared open reading frame resulted in the proposal that this putative SHMT catalyzes an aldol-type condensation reaction utilizing glycine and uridine-5’-aldehyde, resulting in the GlyU core. The enzyme LipK involved in A-90289 biosynthesis was used as a model to functionally assign this putative SHMT to reveal its functions as an l-threonine: uridine-5’-aldehyde transaldolases. Biochemical analysis indicates enzymatic activity is dependent upon pyridoxal-5’-phosphate, is non-reactive with alternative amino acids, and produces acetaldehyde as a co-product. Structural characterization of the enzymatic product is consistent with (5’S,6’S)-GlyU indicating that this enzyme orchestrates a C-C bond breaking and formation resulting in two new stereocenters to make a new l-a-amino acid. The same activity was demonstrated for the LipK homologues involved in the biosynthesis of muraminomicin, A-503083, and A-102395. This l-threonine: uridine-5’-aldehyde transaldolase was used with alternative aldehyde substrates to prepare unusual l-a-amino acids, suggesting the potential for exploiting this enzyme to make new compounds.
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Netzer, Roman. "Untersuchungen zur Glykolyse und zum L-Serin-Stoffwechsel in Corynebacterium glutamicum." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=971436797.
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Hernández, Sánchez Karel. "Nuevas Aplicaciones de la L-Serina Hidroximetiltransferasa y la Benzaldehído Liasa en Síntesis Orgánica." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/285864.
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Las enzimas son importantes aliados en la síntesis de complejas moléculas orgánicas. Estos biocatalizadores ofrecen una elevada quimio, regio y estereoselectividad. Debido a esto se minimiza la formación de subproductos por reacciones competitivas no deseadas y se obtienen, por lo general, productos con una elevada pureza estereoquímica. Una especial atención, por sus aplicaciones en Química Orgánica, han recibido las enzimas que median la formación de enlaces C-C. Estas liasas catalizan la síntesis de moléculas complejas muchas de las cuales poseen variadas actividades biológicas. En el trabajo titulado: Nuevas Aplicaciones de la L-Serina Hidroximetiltransferasa y la Benzaldehído Liasa en Síntesis Orgánica se estudia las potencialidades de estos biocatalizadores en la síntesis de alfa,alfa-diarquía-alfa-aminoácidos, C-arilmonosacáridos y moléculas cíclicas derivadas del 7,8,14,15-tetrahidro-6H-dibenzo[f,j][1,5]dioxacicloundeceno a través de reacciones de carboligación. Para ello este estudio se ha dividido en 3 apartados:
APARTADO 3.1. Se muestra el diseño de nuevas variantes de la L-serina hidroximetiltransferasa de Streptococcus thermophilus (SHMTSth) que catalizan la síntesis de beta-hidroxi- alfa,alfa -dialquil-alfa-aminoácidos. Utilizando la ingeniería de proteínas y un diseño semirracional se incrementó la selectividad de la SHMTSth nativa hacia otros sustratos diferentes de la Gly. Por medio de esta metodología se encontraron tres variantes de la enzima, Y55T, Y55C y Y55S que catalizaron la adición aldólica de D-Ala y D-Ser a diferentes aldehídos. La SHMTSth Y55T resultó ser el biocatalizador más activo y permitió sintetizar beta-hidroxi- alfa,alfa -dialquil-alfa-aminoácidos con una elevada estereoselectividad (> 95 %).
APARTADO 3.2. En este apartado se describe como se acoplan las potencialidades sintéticas de una enzima tiamin dependiente con dos aldolasas a través de dos etapas químicas sencillas en la síntesis de C-arilmonosacáridos. La primera reacción enzimática consistió en la adición benzoínica cruzada de varios aldehídos aromáticos a dimetoxiacetaldehído, catalizado por benzaldehído liasa de Pseudomonas fluorescens biovar I (BAL). Esta reacción alcanzó conversiones superiores al 95 % y se realizó en un sistema tampón:MTBE (1:1 v/v) donde el producto se separó en la fase orgánica y se utilizó directamente en la siguiente etapa de síntesis. Posteriormente se redujeron las (R)-1-aril-2-hidroxi-3,3-dimetoxipropan-1-onas, utilizando NaBH4, con una elevada diastereoselectividad hacia la formación del diol anti (= 90 %). A continuación se hidrolizó el grupo acetal en medio ácido (H2SO4 2 M) y los (2S,3S) 3-aril-2,3-dihidroxipropanal obtenidos fueron utilizados en reacciones de adición aldólicas con diferentes sustratos dadores: dihidroxiacetona (DHA), hidroxiacetona (HA) y glicolaldehído (GO), catalizadas por D-fructosa-6-fosfato aldolasa (FSA) y sus variantes A129S y A129T respectivamente. Esto permitió sintetizar derivados de L-sorbosa (DHA), 1-desoxi-L-sorbosa (HA) y L-xilosa (GO). También se realizó la reacción de adición aldólica de DHA a los dihidroxialdehídos en tampón borato catalizado por L-ramnulosa-1-fosfato aldolasa (RhuA). Por medio de esta reacción se obtuvieron análogos de L-fructosa y L-tagatosa.
APARTADO 3.3 En esta sección se describe la adición benzoínica intramolecular catalizada por BAL. Con la síntesis de varios dialdehídos aromáticos se encontraron los requerimientos estructurales del sustrato para que la enzima catalizara la reacción de carboligación intramolecular. De los posibles sustratos ensayados, el 2,2'-(propano-1,3-diilbis(oxi))dibenzaldehído permitió obtener el ciclo (R)-15-hidroxi-7,8-dihidro-6H-dibenzo[f,j][1,5]dioxacicloundecen-14(15H)-ona como único productos en la reacción enzimática con conversiones superiores al 75 %. A partir de aquí se sintetizaron otros dialdehídos con los que sintetizaron análogos de 7,8,14,15-tetrahidro-6H-dibenzo[f,j][1,5]dioxacicloundeceno. De este estudio se determinó que la BAL cataliza reacciones de adición benzoínica intramolecular de aldehídos aromáticos unidos por una cadena espaciadora, propano-1,3-oxi, en posición 2,2´. La enzima también toleró sustituciones en posición 3,3´y 5,5´ del anillo aromático así como dialdehídos derivados de la piridina.Alpha,alpha-Disubstituted alpha-amino acids are central to biotechnological and biomedical chemical processes as their own sake and as substructures of biologically active molecules for diverse biomedical applications. Structurally, these compounds contain a quaternary stereocenter, which is particularly challenging for stereoselective synthesis. The pyridoxal 5’-phosphate (PLP)-dependent L-serine hydroxymethyltransferase from Streptococcus thermophilus (SHMTSth; EC 2.1.2.1) catalyzes the aldol addition reaction of Gly to aldehydes. We have developed by structure-based engineering a versatile SHMTSth biocatalyst with a wide spectrum of donor and acceptor selectivity overcoming the limitation of the native enzyme for Gly. We have constructed a SHMTSth variant that effectively accomplishes the stereoselective formation of quaternary stereocenters via aldol addition of D-Ala and D-Ser to a wide acceptor scope including aromatic, aliphatic aldehydes as well as hydroxy and nitrogen containing aldehydes to obtain a broad structural variety of alpha-methyl or alpha-hydroxymethyl,alpha-substituted alpha-amino acids. The “de novo” synthesis of carbohydrates and their derivatives (e.g. deoxysugars) is challenging due to the lengthy and time consuming cumbersome protective group strategies. Here, a highly expedient asymmetric synthetic route based on benzoin and aldol biocatalytic reactions for the preparation of new aryl carbohydrate derivatives is presented. The benzoin condensation of aromatic aldehydes to dimethoxyacetaldehyde catalyzed by benzaldehyde lyase from Psedomonas fluorescens biovar I, stereoselective reduction of the carbonyl group and acetal hydrolysis was then followed by the aldol addition of dihydroxyacetone, hydroxyacetone or glycolaldehyde catalyzed D-fructose 6-phosphate aldolase and L-rhannulose-1-phosphate aldolase. New intramolecular benzoin reaction was described using benzaldehyde lyase from Psedomonas fluorescens biovar I as biocatalyst. Different aromatic dialdehydes were tested and the 2,2'-(propane-1,3-diylbis(oxy))dibenzaldehydo yield cycle (R)-15-hydroxy-7,8-dihydro-6H-dibenzo[f,j][1,5]dioxacicloundecen-14(15H)-one as a single products (75 % conversion). Other dialdehydes analogs of A were synthesized and were obtained cycles derivate of 7,8,14,15-tetrahydro-6H-dibenzo[f,j][1,5]dioxaciclo undecene.
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Jordà, Gregory Joan Miquel. "Aproximación sintética a aminoalcoholes y aminoácidos quirales por reacciones de ciclocarbamación de derivados de L-Serina." Doctoral thesis, Universitat de València, 2004. http://hdl.handle.net/10803/10284.
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El presente trabajo tiene como objetivo la síntesis estereoselectiva de oxazinonas y oxazolidinonas quirales a partir del aminoácido natural L-Serina, estos heterociclos constituyen formas protegidas cuya posterior ruptura en condiciones suaves permite obtener aminodioles y aminoácidos con configuración definida. La obtención de oxazinonas y oxazolidinonas quirales se realizo por reacciones de ciclocarbamación de carbamatos alilicos y apertura de epoxidos de carbamatos alilicos. Como muestra de la viabilidad de estos substratos para la obtención de aminodioles y aminoácidos quirales. Se sintetizo los aminodioles quirales (2R,4S)-2-aminopentano-1,4-diol, (1S,3R)-3-amino-1-fenilbutano-1,4-diol y la 2R,4S-g-hidroxinorvalina en su forma de lactona (2R, 4S)--hidroxinorvalina a partir de la oxazinonas (4S,5S,6R) 4-Hidroximetil-5-iodo-6-fenil-1,3-oxazin-2-ona y (4S,5S,6S)-4-Hidroximetil-5-iodo-6-metil-1,3-oxazin-2-ona. Además, la configuración de los carbonos asimétricos en el compuesto Ácido (4R, 6S)-6-metil-2-oxo-1,3-oxazin-4-carboxílico fue confirmada mediante análisis cristalográfico de rayos XThe aim of the present work is the estereoselective synthesis of chiral oxazinones and oxazolidinones from the natural aminoacid L-Serine, these heterocicles constitute protected forms which posterior cleavage in soft conditions allows to obtain aminodiols and aminoacids with definite configuration. The obtaining of chiral oxazinones and oxazolidinones is realized for reactions of ciclocarbamation of allilic carbamates and opening of epoxides of allilic carbamates.As sample of the viability of these substrates for the obtaining of aminodioles and charal aminoacids. I synthesize the chiral aminodiols (2R, 4S)-2-aminopentane-1,4-diol, (1S, 3R)-3-amino-1-phenylbutane-1,4-diol and it 2R, 4S--hydroxinorvaline in its form of the lactone (2R, 4S) - -hydroxinorvaline from the oxazinones (4S, 5S, 6R) 4-Hydroximethyl-5-iodo-6-phenyl-1,3-oxazin-2-one and (4S, 5S, 6S)-4-Hydroximethyl-5-iode-6-methyl-1,3-oxazin-2-one. In addition, the configuration of the asymmetric carbons in the Acid compound (4R, 6S)-6-methyl-2-oxo-1,3-oxazin-4-carboxílic was confirmed by means of analysis cristalographic of RX.
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Scharte, Judith. "Charakterisierung von zwei Stress-induzierbaren Serin-Threonin-Proteinkinasen und eines Transkriptionsfaktors der AP2-EREBP-Familie bei Mesembryanthemum crystallinum L." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967389852.
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Fonseca, Fabiana Vieira. "Isolamento e caracterização de um novo conjunto de serinoproteases com atividade trombina-like e de L-aminoacido oxidase do veneno de Crotalus durissus cascavella." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314482.
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Orientador: Marcos Hikari ToyamaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O uso de toxinas isoladas de venenos como ferramentas moleculares na compreensão de diversos eventos fisiológicos e patológicos tem sido comprovadas por vários trabalhos na literatura. A serpente Crotalus durissus cascavella é encontrada nas áreas de caatinga do nordeste do Brasil, desde o Maranhão até norte do estado de Minas Gerais, e apesar de pouco estudada sua picada constitui um importante problema da saúde pública (Martins et al, 1998). A agregação platequetária é bem caracterizada para a convulxina isolada do veneno de Crotalus durissus cascavella e Crotalus durissus terrificus. O objetivo principal do projeto foi avaliar a atividade de agregação plaquetária induzida por outras frações biológicas e farmacologicamente importantes do veneno total de Cotalus durissus cascavella, que neste projeto foram a crotoxina e giroxina. Através de uma combinação de varias metodologias em HPLC como exclusão molecular, troca iônica e de fase reversa conseguimos isolar os principais constituintes da crotoxina (PLA2, crotapotina e as proteínas ¿trombina-like¿) e a L-aminoácido oxidase a partir da giroxina. Durante o fracionamento do veneno total em coluna de HPLC de exclusão molecular foram detectados dois picos de atividade serino protease, um na fração giroxínica e outro na fração crotoxínica, sendo que na fração crotoxínica encontrou-se uma nova protease até então não caracterizada e na fração giroxínica foram monitoradas a atividade L-aminácido oxidase. Através da cromatografia em HPLC de troca iônica em DEAE 5PW obteve-se a fração Laminoácido oxidase cujo grau de homogeneidade molecular foi confirmado por HPLC de fase reversa. Da fração crotoxínica foram obtidos três grupos principais de proteínas (PLA2, crotapotinas e proteases) e da fração proteolítica foram isoladas três isoformas principais denominadas de F201, F202 e F203, sendo a fração F202, a fração majoritária. F202 foi obtida com maior homegeneidade molecular com massa molecular de 28kDa e mostrou uma alta quantidade de ácido aspártico, ácido glutâmico e outros aminoácidos importantes como histidina, cisteína e lisina. Esta proteína mostrou alta especificidade para BApNA e mostrou um comportamento Michaelis-Menten com Vmáx estimado em 5,64 µM/min e um Km de 0,58mM para este substrato. Neste trabalho foi investigada a habilidade desta proteína em degradar fibrinogênio e observou-se que F202 clivou ambas as cadeias a e ß. A atividade enzimática assim como a agregação plaquetária foi inibida fortemente com a incubação com TLCK, um inibidor específico para serinoproteases. O N-terminal da seqüência de aminoácidos de F202 mostrou alta homologia com outras proteínas ¿trombina-like¿, mas foi significantemente diferente da ¿trombina-like¿ isolada da fração giroxina. Crotalus durissus cascavella apresenta uma fração menos estudada denominada giroxina que tem sido descrita como uma proteína ¿trombina-like¿ como relatado por Raw et al. (1986) e Alexander et al. (1988). Neste trabalho foi demonstrado que a giroxina é uma fração heterogênea composta de uma ¿trombina-like¿ e proteína LAO, a qual parece estar envolvida em várias atividades
Abstract: The use of the isolated toxins from poisons as molecular tools in the understanding of diverse physiological and pathological events has been proved by some works in literature. The serpent Crotalus durissus cascavella is found in the areas of Caatinga Northeast of Brazil, since Maranhão until North of the state of Minas Gerais, and in spite of it hasn¿t been studied a lot, its bite constitutes an important problem to the public health (Martins et al, 1998). The platelet aggregation is well characterized to the isolated convulxin of the poison of Crotalus durissus cascavella and Crotalus durissus terrificus. The main objective of the project was to evaluate the activity of platelet aggregation induced by gyroxin and crotoxin that are biological and pharmacological important fractions of the total poison of Cotalus durissus cascavella. Through a combination of various methodologies in HPLC -as molecular exclusion, ionic exchange and the reverse phase- we managed to isolate the main constituent of the crotoxin (PLA2, crotapotin and the thrombin-like proteins) and the L-amino acid oxidase from the gyroxin. During the fragmentation of the total poison in column of HPLC of molecular exclusion two peaks of serine protease were found: one in the gyroxin fraction and another one in the crotoxin fraction. In the crotoxin fraction a new protease in not characterized yet and in the gyroxin fraction was found the L-amino acid activity oxidase. Through the chromatography in HPLC of ionic exchange in DEAE 5PW that allowed to the attainment of the fraction L-amino acid oxidase whose degree of molecular homogeneity was confirmed by HPLC of reverse phase. From the crotoxin fraction three main groups of proteins (PLA2, crotapotin and proteases) were isolated, and from the named proteolyitic fraction three isoforms of F201, F202 and F203, noticing that the F202 fraction is the major one. The fraction F202 showed a high quantity of aspartic acid, glutamic acid and others amino acids very important as histidine, cysteine and lysine and so more molecular homogeneity could be obtained and with molecular mass of 28kDa. This protein whose behavior Michaelis-Menten with Vmáx measured in 5,64 µM/min and one Km de 0,58 mM to this substratum showed high specificity to BapNA. In this work was investigated the ability of this protein in degrading the fibrinogen and was observed that the F202 made the cleavage into both chains a and ß. The enzymatic activity as well as the platelet aggregation were strongly inhibited with the incubation with TLCK, a specific inhibitor to serine protease. The N-terminal of the amino acid sequence of F202 showed the high homology with other proteins thrombin-like, but it was significantly different from thrombin-like isolated fro m the gyroxin fraction. Crotalus durissus cascavella presents a fraction less studied named gyroxin that has been described as a protein thrombin-like as related by Raw et al. (1986) and Alexander et al. (1988). In this work was demonstrated that the gyroxin is a composed heterogeneous fraction of one thrombin-like and protein LAO, and this seems to be involved in some activities
Mestrado
Bioquimica
Mestre em Biologia Funcional e Molecular
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Lan, Jie. "Escherichia coli mutants unable to use a combination of L-serine, glycine and L-leucine as carbon source." Thesis, 1997. http://spectrum.library.concordia.ca/463/1/MQ39951.pdf.
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Previously, medium containing a combination of L-serine, glycine and L-leucine (SGL medium) has been used to study the characteristics, including the activation system, of L-serine deaminase (L-SD), an interesting enzyme from Escherichia coli that is first synthesized in an inactive form. In this thesis, I isolated two new E. coli SGL- mutants through $\lambda$placMu insertion. All these mutants MEW20b and MEWb1 are quite likely involved in the activation of L-SD enzyme. Applying inverse PCR technique, I identified the mutated gene in these two mutant strains to be nuoM and torA respectively. A formerly isolated SGL- mutant MEW84 was also identified as a $\lambda$placMu insertion in the glpC gene. Further experiments proved that mutations in these three genes actually were responsible for the SGL- phenotype of the mutant strains. A comparison of the functions of the three mutated genes suggests that electron donation may be part of the process necessary to activate L-SD. Physiological studies were carried out to investigate further these three mutants.
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Guay, Caroline. "Expression et rôle d'une nouvelle protéase à sérine : l"eosinophil serine protease"-1 /." 2007. http://www.theses.ulaval.ca/2007/24677/24677.pdf.
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Brown, Elizabeth Alison. "A relationship between L-serine degradation and methionine biosynthesis in Escherichia coli K-12." Thesis, 1989. http://spectrum.library.concordia.ca/4641/1/ML51314.pdf.
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Antflick, Jordan. "More than a Metabolite: An Evaluation of the Potential Role of L-serine-O-phosphate as the Endogenous Agonist for the Group III Metabotropic Glutamate Receptors." Thesis, 2012. http://hdl.handle.net/1807/32651.
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The Group III metabotropic glutamate receptors (mGluR) are located presynaptically on axon terminals and act as autoreceptors and heteroreceptors by inhibiting neurotransmitter release. Much has been learned about these receptors through exogenous application of L-serine-O-phosphate (L-SOP), an endogenous amino acid derivative and known activator of the Group III mGluRs. We hypothesized that L-SOP is the endogenous co-agonist at the high affinity Group III mGluR, mGluR4. We found the EC50 of L-SOP at mGluR4 was 0.5 μM, and determined that the concentration of L-SOP in whole brain was approximately 5 μM. An immunocytochemical survey revealed that cells containing the enzymatic machinery necessary for L-SOP synthesis and metabolism were observed in two brain regions known to express mGluR4, namely, cerebellum and hippocampus. In the cerebellum, the L-SOP synthetic and metabolic enzymes were found in Bergmann glia and Purkinje cells, two cells which form a tripartite synapse with parallel fiber axon terminals where the mGluR4 subtype is exclusively expressed at high levels. In the hippocampus, the L-SOP metabolic enzyme was detected in young neurons emanating from the neurogenic subventricular zone. Attempts to raise endogenous levels of L-SOP by crippling the L-SOP metabolizing enzyme (phosphoserine phosphatase), over-expressing the L-SOP synthesizing enzyme (phosphoserine aminotransferase), or through dietary protein restriction, to study the effects on neurotransmission and neurodevelopment in the central nervous system (CNS) were unsuccessful, suggesting that the production of L-SOP remains stable despite manipulation of the synthetic and metabolic enzymes. Finally, the ability of L-SOP to modulate glutamate release from presynaptic terminals was examined in cerebellar synaptosomes. Co-incident activation of presynaptic mGluR4 and presynaptic GABAA receptors facilitated glutamate release, suggesting that simultaneous activation of parallel fibers and Bergmann glia may serve to enhance synaptic transmission. This observation expands the traditional view of Group III mGluRs acting solely as inhibitory autoreceptors. Taken together, these results provide compelling evidence to support the hypothesis that L-SOP is the endogenous agonist at mGluR4, and possibly other Group III mGluRs.
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Tang, Ye Man. "Role of nine cysteine residues in L-serine deaminase 1 from Escherichia coli K-12." Thesis, 2004. http://spectrum.library.concordia.ca/8340/1/MR04344.pdf.
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L-serine deaminase 1 (L-SDI) is one of three enzymes that break down L-serine to produce pyruvate and ammonia in Escherichia coli K-12. L-SD1, a 454 amino acid protein encoded by sdaA gene, contains nine cysteine residues at the 181, 219, 290, 339, 347, 366, 381, 392, and 453 positions. Blast results show that three cysteines at positions 339, 381 and 392 are in what is then a highly conserved motif is found in most L-SDs that have a Fe-S cluster. The other six cysteine residues are also conserved among some bacterial L-SDs. In this study, all nine cysteine residues have been mutated individually. Assay of enzyme activity both in vivo and in vitro shows that: (1) eight of nine cysteine residues play an important role in L-SD1 activity; (2) the cysteine at position 181 might be non-essential for L-SD1 activity; (3) cysteines at positions 339, 381 and 392 are essential for L-SD1 activity. This is consistent with the demonstration by Cicchilo and his colleagues that L-SD1 uses a 4Fe-4S cluster for the deamination of L-serine. If so, cysteine residues 339, 381 and 392 are probably essential for this iron-sulfur cluster and ligate to three iron molecules of a 4Fe-4S cluster.
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Monette, Anne. "The effects of cpx genes on the regulation of L-serine metabolism in Escherichia coli K-12." Thesis, 2006. http://spectrum.library.concordia.ca/9052/1/MR20724.pdf.
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The E. coli ssd mutant is so "sick" that it accumulates suppressor mutations that only partially restore the parental strain phenotype. Based on map location and phenotypic similarities, the ssd was annotated as a cpxA mutation despite unique phenotypes of its own. Here, the ssd mutation and one suppressor mutation are shown located within the cpx regulon, and each strain carrying a cpxR , cpxP or cpxA deletion demonstrates part of the ssd phenotype. The cpxA * gain-of-function and cpxA deletion mutants are shown to have similar phenotypes likely because they both lack the phosphatase responsible for inactivating CpxR. Many deletion mutants are screened from the glycolytic, serine metabolism and Cpx pathways to reveal previously unknown gene products regulating growth on serine. A mucoid phenotype can arise in ssd , cpxR and cpxP mutants, whereas the cpxA mutants alone can have an effect on L-serine deaminase activity---indicating that the Cpx proteins have roles outside of the Cpx two-component regulatory system. RNA expression analysis reveals that the cpxP transcript is increased in ssd mutants, constitutive in the parent strain, and differentially regulated in cpxR and cpxA deletion mutants. Fluorescence microscopy techniques show that ssd mutant filaments do not have a damaged membrane despite a lack of proper DNA segregation, and merodiploid parental and ssd strains having an extra copy of ZipA have improper DNA segregation in cells that make filaments and lyse extensively.
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Zhang, Xiao. "Loss of its three L-Serine deaminases causes major changes in metabolism of Escherichia coli K-12." Thesis, 2009. http://spectrum.library.concordia.ca/976239/1/NR63455.pdf.
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The Escherichia coli genome codes for three highly homologous enzymes which use a 4Fe-4S mediated catalysis to deaminate L-serine and generate pyruvate and ammonia. The three enzymes are encoded by the genes sdaA, sdaB and tdcG . Enzymes of this type are found in many prokaryotes, and are not found in any eukaryotes. Despite the fact that the first E. coli L-serine deaminase (L-SD) was identified in 1955, and the regulation of its expression has been extensively studied, the physiological function of this delicately regulated enzyme is still unknown. In part one of this work, the impact of L-SD on the metabolism of E. coli K-12 was studied by creating a strain from which all three genes were deleted. This strain has serious growth problems. While the triple mutant grows well in glucose minimal medium even with L-serine, it forms long filaments on subculture into Luria Broth (LB). On subculture into minimal medium with glucose and casamino acids (CAA), it forms very large, abnormally shaped cells, many of which are osmotically sensitive and lyse. The processes of DNA replication and cell division are both abnormal in the triple mutant cell grown with CAA. Further study indicated that the triple mutant is unable to maintain sufficient production of one-carbon (C1) units. Provision of an exogenous supply of S-adenosylmethionine (SAM) restores cell division in LB, and repairs much of the difficulty in growth in medium with CAA. Whereas cells grown with CAA in the absence of SAM show abnormal FtsI production and localization within filaments, the addition of SAM produces filaments and normal recruitment of FtsI into the division septum. In part two, a mutant MEW128 which had been shown to be deficient in post-translational activation of L-SD was investigated. The mutation in that strain was located in ygfZ , a gene of unknown function. Neither MEW128 nor a strain known to carry a ygfZ deletion produces an active L-SD. Very little is known about the function of YgfZ, though it has been crystallized and shown by Teplyakov et al. to bind folates. The possibility that it is involved in assembly of the iron sulfur cluster (Fe-S) is considered.
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Teixeira, Beatriz Isabel Brites. "Preparação e caraterização de scaffolds de colagénio-nanohidroxiapatite modificados com o-phospho-L-serine para a regeneração tecidular óssea." Master's thesis, 2016. http://hdl.handle.net/10400.14/22224.
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O tecido ósseo é constantemente submetido a processos dinâmicos e fisiológicos inerentes à reabsorção e à formação óssea, de modo a garantir a integridade do esqueleto. Na maioria dos casos, o processo de reparação óssea é desencadeado pela fragilidade ou fratura do osso, como por exemplo em caso defeitos de grandes dimensões. Porém, o processo de reparação nem sempre ocorre de forma ideal. Neste sentido, novas estratégias terapêuticas coadjuvantes ao processo de reparação óssea tem vindo a ser exaustivamente estudas pela Engenharia de Tecidos. Atualmente, alguns biomateriais ou materiais biomiméticos tem vindo a ser utilizados na prática clínica em substituição dos enxertos autólogos reconhecidos como gold standard. A variedade destes materiais tem vindo a propiciar, progressivamente, o sucesso de tratamento. Contudo, o material ideal para a regeneração óssea requer ainda mais investigação. Este material deve ter propriedades similares ao osso natural como osteointegração, osteoindução e osteogénese. O objetivo desta dissertação consiste em reportar as propriedades físico-químicas e mecânicas dos scaffolds biocompósitos de colagénio/nano-hidroxiapatite modificados com O-phospho-L-serine (fosfoserina), obtidos através do método de criogelação, como potenciais substitutos ósseos. A análise da morfologia e da superfície dos biocompósitos foi realizada utilizando a Microscopia Eletrónica de Varrimento (SEM) e os resultados mostraram que os criogéis produzidos apresentam uma estrutura altamente porosa com a presença de cristais nanométricos de hidroxiapatite. De acordo com a análise química resultante da Espetroscopia de Infravermelho por Transformada de Fourier (FT-IR), os picos de colagénio e hidroxiapatite nos scaffolds biocompósitos coincidem com os valores reportados na literatura e a fosfoserina não interfere com a ligação formada pelas moléculas de colagénio e os agregados de hidroxiapatite. O resultado do teste de absorção de solventes revela que diferentes concentrações do aminoácido em estudo têm influência da captação de água, isto é, os scaffolds biocompósitos de colagénio/nano-hidroxiapatite com maior concentração de fosfoserina apresentam maior captação de água comparativamente às amostras com menor concentração de aminoácido. Por outro lado, quando as amostras são emergidas em PBS (tampão salino), os scaffolds com fosfoserina mostram menor coeficiente de absorção. Por fim, segundo a análise dinâmico-mecânica, as amostras com fosfoserina apresentam uma redução das propriedades mecânicas, mas não significativamente, enquanto as propriedades viscoelásticas apresentam alteração, revelando deformação da amostra. Os resultados deste estudo permitem concluir que os scaffolds biocompósitos de colagénio/nano-hidroxiapatite com fosfoserina apresentam propriedades físico-químicas e mecânicas propícias a estudos in vitro com culturas celulares.In order to mantain a healthy skeleton, bone tissue is constantly subjected to dynamic and physiological processes of reabsorption and new bone formation. Usually, the process of bone healing is triggered in some cases of tissue fragility or tissue damaged like e.g. large defects. In other way, sometimes the healing process does not respond approprieately. Fortunately, bone tissue engineering offers new therapeutic strategies to aid in the muscoskeletal healing. The development and use of biomaterials or biomimetic materials that can replace autologous grafts, recognized as gold standard, are often used today in daily clinical practice. Besides increased the range of choice, these biomaterials also have improved the clinical treatment. Nonetheless, the ideal material for bone regeneration requires further investigation. This material must have the same characteristics that we find in the native bone such osteointegration, osteoinduction and osteogenisis properties. This dissertation try to investigate and expose the physicochemical and mechanical properties of collagen/nano-hydroxyapatite biocomposites scaffolds modified with O-phospho-L-serine (phosphoserine), obtained by cryogelation method, as potential bone substitutes. Morphology and surface analysis was performed using Scanning Eletron Microscope (SEM) and revealed that all cryogel scaffolds had highly porous structure with interconnective porosity with the presence of nanometric crystals of hydroxyapatite. According to the chemical analysis through Fourier Transform Infrared Spectroscopy (FT-IR), the peaks of collagen and hydroxyapatite in the biocomposite scaffolds are coincident with the values reported in the literature and the phosphoserine do not interfer with the link between collagen molecules and hydroxyapatite aggregates. The swelling tests has been shown that different concentrations of the aminoacid in study, have influence in water uptake, i.e., collagen/nano-hydroxyapatite biocomposites scaffolds with high content of phosphoserine display higher water uptake than low phosphoserine content. On the other hand, when the samples are in PBS (phosphate buffer), the samples with phosphoserine show lower degree of swelling behavior. Finally, in agreement with Dynamic Mechanical Analysis (DMA), the samples with phosphoserine show lower mechanical properties, but no significantly, even as visco-elastic properties have changed and reveals samples deformation. The results of this investigation allow to assert that collagen/nano-hydroxyapatite biocomposite scaffolds modified with phosphoserine exhibit advantgeous physicochemical and mechanical properties for in vitro studies.
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Feng, Xiao-peng. "Study of MEW84 : a mutant related to the post-translational modification of L-serine deaminase in Escherichia coli K-12." Thesis, 1990. http://spectrum.library.concordia.ca/4349/1/MM64736.pdf.
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Chiu, Chih-Hao, and 邱致豪. "Molecular identification and characterization of a serine carboxypeptidase-like gene associated with abiotic stress in tea plant, Camellia sinensis (L.)." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/14166991681895005512.
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碩士國立中興大學
生物科技學研究所
103
Tea (Camellia sinensis L.) is grown in more than 30 countries, and is the most widely consumed beverage in the world aside from water. Tea contains many secondary metabolites, especially polyphenolic compounds and flavonoid. The main substances causing astringent taste in oolong tea are catechins. It has been shown that gallate-type catechins are far more astringent than non-gallate-type catechins. Previous research had shown that the Serine carboxypeptidase-like (SCPL) proteins have involved in galloylated catechin biosynthesis. We isolated a CsSCPL gene encoding a serine carboxypeptidase-like protein from oolong tea plant. The full-length CsSCPL cDNA contains a 1440-bp open reading frame, encoding a protein of 480 amino acids with a calculated molecular mass of 54.5 kDa and an isoelectric point of 5.25. Sequence alignment analyses showed that CsSCPL is a serine carboxypeptidase with high homology to other SCPL proteins, including DkSCPL (persimmon), VvSCPL (grape), FvSCPL (woodland strawberry), and CsSCPL17 (sweet orange). Quantitative RT-PCR analyses revealed that the highest transcript levels of CsSCPL were in young leaves of tea seedlings and in buds of mature tea plants. The CsSCPL transcript levels increased in response to heat stress but decreased in response to cold, high salinity, and drought stresses. The degree of catechin galloylation was positively correlated with CsSCPL transcript levels after heat treatments. During four growing seasons, the CsSCPL was presented highest transcript levels in summer, which has the highest mean monthly temperature in the field. In silico promoter analysis presented that the CsSCPL promoter contains several important cis-elements which regulated by light, heat, cytokinin, and ethylene. Our results may provide useful information for further research on SCPL function in plants and oolong tea manufacture in the future.
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Chalaire, Katelyn Cox. "The Biological and Molecular Analysis of a Tick-Encoded Serine Protease Inhibitor (S6) and its Role in the Feeding Cycle of the Lone Star Tick, Amblyomma americanum (L) (Acari: ixodidae)." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8255.
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Serine protease inhibitors (serpins) are a large superfamily of proteins that regulate critical proteolytic pathways by inhibiting serine proteases. Tick-encoded serpins are thought to play a vital role in the feeding process. To determine the relationship of Amblyomma americanum serpin 6 (S6) to tick feeding regulation, this study attempted to define the biological significance of this molecule through transcription and protein expression profiles, biochemical characterization of recombinant s6 (rS6), and the effects of in vivo post-transcriptional gene silencing on blood meal acquisition and fecundity.
Transcriptional analysis revealed that S6 mRNA is ubiquitously expressed in unfed and partially fed ticks through the initial 5 days of the feeding period. S6 mRNA abundance in dissected tick organs showed a 3.7, 3.4, and 1.7- fold upregulation from 24 h to 96 h in the salivary gland (SG), midgut (MG) and the carcass (CA) remnant after removal of SG, MG respectively before downregulating at 120 h. Native S6 protein is downregulated in response to tick feeding, with correlation between transcription and protein expression profiles only consistent from the unfed to 48 h. Similarly, S6 protein expression in dissected female tick tissues is reduced as feeding progresses, with S6 being identified in SG, MG, ovary (OV), and CA from 24 h until 72 h. Biochemical characterization of S6 was not achieved, as rS6 did not form an irreversible complex when incubated with chymotrypsin or trypsin. Although complete silencing of S6 and S6/S17 mRNA was achieved, post-transcriptional gene knockdown had no effect on tick feeding efficiency or fecundity. These findings have been discussed in regards to the development of a vaccine against A. americanum and necessary future studies have been suggested for further characterization and assessment of biological significance.
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Bencze, Michal. "Účinky L-serinu a vliv anestézie na regulaci krevního tlaku u normotenzních a hypertenzních potkanů." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-307813.
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Anesthetics cause profound alterations in respiratory and cardiovascular systems. Our experiments demonstrated that different anesthetics caused different changes in blood pressure regulating components. The role of particular BP regulating systems was disclosed by their selective inhibition - sympathetic nervous system blocked by pentolinium (peripheral ganglionic blockade), renin-angiotensin system by captopril (angiotensin converting enzyme blocker) and nitric oxide production by L-NAME (nitric oxide synthase blocker). Components of blood pressure regulating mechanisms in conscious normotensive Wistar rats and spontaneously hypertensive rats were compared with four different groups of anesthetized rats by pentobarbital, ketamine-xylazine, chloralose-urethane and isoflurane. Each anesthesia caused different hemodynamic changes. If hemodynamic conditions should be similar to conscious rats, the most suitable anesthetic is pentobarbital. L-serine-induced effects represent endothelium-derived hyperpolarizing factor (EDHF)-mediated response, which is a type of endothelium-dependent regulation of vascular tone, independent of nitric oxide and prostacyclin production. Pronounced L-serine effects on blood pressure were shown in NO-deficient type of hypertension. Our study demonstrated its pronounced effects in...
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Stolz, Michael [Verfasser]. "Untersuchungen zur L-Serin-Bildung mit Corynebacterium glutamicum / vorgelegt von Michael Stolz." 2006. http://d-nb.info/982789254/34.
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Antonicelli, Gerardo Esteban. "Änderung der Glycindecarboxylase- und Serinhydroxymethyltransferase-Aktivität in Blättern:." Doctoral thesis, 2005. http://hdl.handle.net/11858/00-1735-0000-0006-AC51-B.
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Netzer, Roman [Verfasser]. "Untersuchungen zur Glykolyse und zum L-Serin-Stoffwechsel in Corynebacterium glutamicum / vorgelegt von Roman Netzer." 2003. http://d-nb.info/971436797/34.
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Chen, I.-Jung, and 陳怡蓉. "Study on Antioxidative and Antibacterial properties of Momordica charantia L. var. abbreviata Seringe Leaf and stem." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/37555280010388237852.
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碩士國立宜蘭大學
食品科學系碩士班
97
In this study, the leaves and stems of Momordica charantia L. var. abbreviata Seringe (MCs) were evaluated their antioxidative properties, antioxidative contents and antibacterial activity. After freeze or hot-air drying treatments, different organic solvents were used to extracted the leaves and stems . Final tried to make the bitter melon tea, studied its antioxidative properties. The results showed the leaves and stems after freeze or hot-air drying treatments were evaluated their antioxidative properties, the methanol extracts showed 80% inhibition of peroxidation, 90% scavenging DPPH free radical. But the water extracts showed only 40% scavenging DPPH free radical. When 0.4mg/mL of leaves and stems of water extracts had 95%, 90% chelating ability ferrous ions, respectively, better than methanol or ethyl acetate extracts. Additional, the leaves and stems of methanol extracts showed the highest reducing power, which was 5-10 times those ethyl acetate and water extracts. Analysis the leaves and stems antioxidant contents of total phenol, flavonoids and chlorophyll, the results showed in two drying treatments was freeze > hot-air drying, was leaf > steam, and in three organic solvents were methanol > ethyl acetace > water extracts. Of the various catalysts evaluated, we found that the freeze drying treatment of leaves by methanol extracts, its extracts had best inhibition of peroxidation, scavenging DPPH free radical and reducing power, and better than stems. But the hot-air drying treatments of leaves by water extracts had better chelating ability ferrous ions. The antibacterial activity of MCs leaves or stems by hot-air drying treatment and methanol extract, the minimum bactericidal concentration (MBC) value for Staphylococcus aureus was 12.5mg/mL (leaves), 6.25mg/mL(stems); and for Escherichia coli the methanol extract concentration up to 25mg/mL. The bitter melon tea after hot water extracted for 90 seconds had the best antioxidative activities. The antioxidative analysis : 71.9% inhibition of peroxidation, 39.1% scavenging DPPH free radical, 83.1% chelating ability ferrous ions and 0.402 reducing power, respectively. The bitter melon tea after hot water extracted for 180 seconds had the highest antioxidant contents of total phenol(31.42μg/g), flavonoids(31.42μg/g).
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Tsai, Chung-Huang, and 蔡崇煌. "Wild Bitter Gourd (Momordica charantia L. var. abbreviata Seringe) Improves Metabolic Syndrome: A Preliminary Dietary Supplementation Trial." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/34692825882082127046.
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博士朝陽科技大學
生化科技研究所博士班
100
Bitter gourd has been shown to activate both PPARα/γ, ameliorate insulin resistance and abdominal obesity in high-fat fed mice. The aim of this study was to evaluate the effect of F1 hybrid Hualien wild bitter gourd No.4 (WBG; Momordica charantia L. var. abbreviata Seringe) on metabolic syndrome (MetS) in Taiwanese adults. A preliminary open-label uncontrolled trial was conducted in eligible fulfilled the diagnosis of MetS based on Asian guidelines of the American Heart Association/National Heart, Lung and Blood Institute between May 2008 and April 2009. Forty-two MetS patients (21 men and 21 women) with mean age of 45.7±1.8 years (range, 23-63 years) were recruited for the study. The subjects were supplemented with 4.8 gram of lyophilized powder of WBG in capsules daily for 3 months. MetS and associated parameters were monitored monthly for six consecutive months including 3 months of supplementation and another 3 months after the discontinuing supplementation. Effects of WBG on MetS were estimated using generalized linear mixed models according to the intention-to-treat principle. There were 7.1% (standard error of mean, p value; 3.7%, 0.920), 9.5% (4.3%, 0.451), 19.0% (5.7%, 0.021), 16.7% (5.4%, 0.047), 11.9% (4.7%, 0.229) and 11.9% (4.7%, 0.229) decrease in the incidence rate of MetS in the end of each month respectively after the start of the supplementation. The waist circumference also significantly decreased after the supplementation (p<0.05). The WBG supplementation was generally well-tolerated. This is the first report to show that WBG improved MetS. It reached the statistical significance in the third month and in the first month after discontinuing WBG supplementation. These preliminary results provide a firm base for further randomized control trials to evaluate the efficacy of WBG supplementation.
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Chuang, Chia-Ying, and 莊佳穎. "Isolation and identification of the activators of nuclear receptor PPARs in Momordica charantia L. var. abbreviate Seringe." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/97923457264266189303.
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碩士國立臺灣大學
微生物與生化學研究所
92
The peroxisome proliferators-activated receptors (PPARs) are dietary lipid sensors that regulate fatty acids and carbohydrate metabolism, and which are ligand-activated transcription factors belonging to the nuclear receptor superfamily. The hypolipidemic effects of the fibrate drugs and the antidiabetic effects of the glitazone drugs in humen are mediated by the PPAR�� and PPAR�� signalling, respectively. In a previous study, Chao (2003) found that the ethyl acetate (EA) extract of wild bitter melon (Momordica charantia L. var. abbreviate Seringe) could activate PPAR�� and PPAR��. The aim of the study is to isolate and identify the activators of nuclear receptor PPAR�� and PPAR�� in wild bitter melon. The EA extract of wild bitter melon was partitioned with n-hexane and 90% methanol / 10% H2O, and the n-hexane extract was futher separated by silica gel column chromatography and preparative HPLC. A transactivation assay employing a clone of CHOK1 cells stably transfected with a (UAS)4-tk-alkaline phosphatase reporter and a chimeric receptor of GAL4-rPPAR�� LBD was used to track the active component. Mass spectroscopy and NMR were used to elucidate the chemical structure of the active compounds. The isolated 9cis, 11trans, 13trans-18:3 conjugated linolenic acid (9c, 11t, 13t- CLN) was found to activate PPAR�� to an extent that was equivalent to the positive control, 5 �嵱 Wy-14643 (p<0.05). Compared to common fatty acids, including oleic acid, linoleic acid and linolenic acid, 9c, 11t- CLA and 9c, 11t, 13t- CLN activated PPAR���nto�na higher extent. The isolated 9c, 11t, 13t- CLN was then incorporated into the medium to treat a peroxisome proliferators-responsive murine hepatoma cell line, H4ⅡEC3, for 72 hours. Treated cells showed significantly higher activity of acyl-CoA oxidase compared to Wy-14643, indicating that 9c, 11t, 13t- CLN was able to act on a natural PPAR�� signaling pathway in this cell line. The content of 9c, 11t, 13t- CLN in wild bitter melon was estimated to be about 7.1 g / kg dried wild bitter melon and about 0.42 g / kg fresh wild bitter melon. By monitored the UV spectroscopy of 9c, 11t, 13t- CLN in EA extracts prepared from seeds and flesh of wild bitter melon, respectively. The 9c, 11t, 13t- CLN was found to be mainly distributed in the seeds. However, the EA extract of seeds and flesh both showed significantly PPAR�� activation. Among 7 strains of wild bitter melon, the fold of PPAR�� activation was not correlated to the content of 9c, 11t, 13t- CLN estimation by UV absorption at 268.8 nm implying the possible existence of other active compounds in wild bitter melon. To identify the compounds that activate PPAR�� in wild bitter melon, a transactivation assay employing a clone mixture of reporter gene transient and a chimeric receptor of GAL4-rPPAR�� LBD was cotransfected into CHOK1 cells and used to track the fractionation procedure used to isolate PPAR�� activator described above. The active fraction in wild bitter melon was found to be a mixture of phytolsterols. In conclusion, we isolated and characterized, from wild bitter melon, 9c, 11t, 13t- CLN and a phytolsterol mixture that can function as activators of PPAR�� and PPAR��, respectively. The results suggest that wild bitter melon has a potential to develop as a healthy food for hyperglycemia and hyperlipidemia.
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Domanoldou, Nathalie [Verfasser]. "Rolle der Serin-Threonin-Proteinphosphatasen bei der Regulation der L-Arginin-abhängigen Stoffwechselwege in Alveolarmakrophagen / Nathalie Domanoldou." 2009. http://d-nb.info/999002023/34.
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Růžičková, Kateřina. "Charakterizace fosfatas v rostlinách tabáku (Nicotiana tabacum L.)." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-313077.
Full textAbstract:
Phosphateses (EC 3.1.3.x) are a group of enzymes that hydrolyze phosphoesters. That way they affect the energetic metabolism of a cell and its regulation. Phosphatases that dephosphorylate proteins are an integral part of signaling pathways, stress responses and they modulate enzymatic activity. This thesis deals with the study of phosphatases obtained from tobacco leaves (Nicotiana tabacum, L.). Solution of enzymes was prepared by extraction in both acidic and alkaline buffers. Through the use of the chromogenic substrate pNP-phosphate it was determined that there is a higher phosphatase activity in the glycosylated fraction than in the fraction that did not bind to Con A Sepharose. The research of the ions effect on the phosphatase activity has determined that Mg2+ and Ca2+ show positive effect on the phosphatase activity while the effect of Co2+ and Mn2+ is inhibitory. The Zn2+ ions have shown no effect whatsoever. The glycosylated phosphatases also dephosphorylated low-weight-molecular substrates phosphoserine, ATP and glucose-6-phosphate. The research of protein phosphatase activity discovered the affinity to the substrate phosvitin, although neither to casein nor its tryptic cleaves. Detailed experiments have shown that the pH optima for all the substrates lie from pH 5 to 6. Glycosylated phosphatases...