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The camera obscura and the pursuit of the uncannyStorey, Jacqueline Anne January 2005 (has links)
This practice based research seeks to explore and extend the potential of camera obscura projections to perceptually transform objects and spaces by using their unique visual qualities. These pertain to immediacy and directness. Although apparently tangible, the projected images appear to reside in a void where there is an absence of surrounding visual reference. This causes the images to appear disconnected from any context, thereby prompting associations with Freud's notions of the uncanny and Proust's narrative of the transitional. The research consists of a sequence of practice based studies. These commenced with an exploration into the perceptual ambiguities of reflection and shadow. Perceptual ambiguity was further explored through the distorting effects of curved pinhole cameras. The latter began to suggest using the camera itself as an object within which something could be viewed. With the incorporation of focusing lenses, this led to projections where the observer was situated within the camera obscura. Throughout the research, the objects projected were always ordinary and familiar, commencing with a light bulb. The addition of lighting sequences thus enabled further exploration of various phases of ambiguity, as well as enhanced definition and recognition of the projected image. This was followed by projections of other objects, which sought to place them in a particular visual context; for example a mug projected into' an actual microwave located within a kitchen. Although this produced surreal connotations, the surrounding visual material diluted the impact of the projected image. A decision was therefore made to concentrate entirely on the presentation of the projected images by refining projection techniques to enhance their quality and definition. The introduction of movement subsequently heightened perceptual ambiguity, as did the addition of the multiplication of images. This led to a rich variety of projected imagery which ranged from the perceptible to the imperceptible, involving synchronicity, transparency, juxtaposition, transposition from line to plane, and contrast between stasis and movement. The increasingly extraordinary images prompted a reevaluation of the observer's visual assumptions. These practical investigations, together with historical, literary, and philosophical issues, combine to extend the possibilities of the camera obscura in terms of contemporary artistic practice.
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Etude du polymorphisme génétique de la N-Acétyltransférase de type 2 dans la population sénégalaise : prévention de la toxicité et de l’échec thérapeutique de l’isoniazide dans la prise en charge de la tuberculose / Study of N-acetyltransferase 2 genetic polymorphism in the Senegalese population : preventing toxicity and treatment failure of isoniazid in the treatment of tuberculosisTouré, Aminata 10 December 2012 (has links)
Un xénobiotique subit plusieurs étapes de biotransformations simultanées ou successives dont les principaux sites sont les tissus situés à l’interface entre l’organisme et le milieu extérieur, à savoir : le tube digestif, l’appareil respiratoire, le rein et le foie. Ce dernier étant fonctionnellement le plus important. Les phases réactionnelles principales constituant les étapes de détoxification, phase I, phase II et phase III, ne sont possibles que par l'intervention de systèmes enzymatiques spécifiques. Etant donné la grande diversité des xénobiotiques auxquels l'organisme est exposé, il existe une multitude d'enzymes présentant des spécificités variées. Les réactions de biotransformation des xénobiotiques s'enchaînent rarement de façon linéaire, car deux voies ou plus prennent souvent naissance à partir d'un métabolite donné. On comprend dès lors que l'existence d'un variant enzymatique défectif pour l'une de ces voies réactionnelles pourra orienter le métabolisme d'une substance donnée vers une autre voie. Cette dernière, généralement mineure, prendra donc une grande importance et les polymorphismes qui la concernent pourront orienter le devenir des métabolites ainsi formés. La famille des N-acétyltransférases (NATs) fait partie des enzymes assurant principalement la réaction de conjugaison de la phase II de détoxification des xénobiotiques. Le polymorphisme des NATS représente l'un des exemples de variation pharmacogénétique décrit, et de l'un des plus documentés, depuis sa découverte au début des années 50, en même temps que la découverte de la grande efficacité de l’isoniazide (INH) dans le traitement de la tuberculose.Les travaux de cette thèse avaient pour objectif d’étudier le profil d’acétylation de la NAT2 dans la population sénégalaise afin de les répartir en acétyleurs lents et en acétyleurs rapides, et de déterminer la cinétique de l’isoniazide chez des sujets tuberculeux en corrélation avec les résultats de génotypage. L’étude des mutations du gène NAT2 a été effectuée par PCR-séquençage directe et a permis de mettre en évidence 11 variants alléliques dans la population sénégalaise.l’activité enzymatique de la NAT2 a été déterminée par utilisation du test à la caféine et le rapport des ratios des métabolites majeurs a permis classer les sénégalais en acétyleurs lents et rapides. La cinétique de l’isoniazide a utilisée la chromatographie UPLC-MS/MS. Ce travail présente les premiers résultats de l’étude de la NAT2 dans la population sénégalaise qui pourront être utilisés pour une meilleur optimisation de l’utilisation de l’INH dans la prise en charge de la tuberculose, maladie à forte prévalence en Afrique. / Xenobiotic biotransformation undergoes several stages of simultaneous or successive whose main attractions are the tissues at the interface between the organism and the external environment, namely: digestive, respiratory, kidney and liver. The latter being the most important functionally. The reaction phases constituting the main stages of detoxification, phase I, phase II and phase III, are possible only through the intervention of specific enzyme systems. Given the wide diversity of xenobiotics to which the organism is exposed, there are a multitude of enzymes with various specificities. The biotransformation reactions of xenobiotics are linked linearly rarely, because two or more lanes are often born from a given metabolite. It is therefore understandable that the existence of an enzyme variant defective for one of these reaction pathways can direct the metabolism of a given substance to another track. The latter, usually minor, will therefore important and polymorphisms that concern will guide the fate of metabolites thus formed. The N-acetyltransferases (NATs) is part of enzymes that primarily the conjugation reaction of phase II detoxification of xenobiotics. The polymorphism of NATS is one of the examples of pharmacogenetic variation described, and one of the most documented since its discovery in the early \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'50s, along with the discovery of the high efficacy of isoniazid (INH) in the treatment of tuberculosis. The work of this thesis aimed to study the profile of the NAT2 acetylation in the Senegalese population in order to distribute them in slow acetylators and rapid acetylators, and determine the kinetics of isoniazid in tuberculous subjects correlated with the results of genotyping. The study of mutations of the NAT2 gene was performed by PCR-direct sequencing and allowed to identify 11 allelic variants in the Senegalese population. The enzymatic activity of NAT2 was determined by using caffeine test and the ratios of major metabolites allowed Senegalese classify fast and slow acetylators. The kinetics of isoniazid used UPLC-MS/MS chromatography.
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NHCs in organocatalysis : azolium enolate generation and synthetic applicationsDouglas, James J. January 2012 (has links)
This thesis details investigations into organocatalytic reactions promoted by N Heterocyclic Carbenes (NHCs) that proceed via an assumed azolium enolate intermediate. Initial research focused on the catalytic asymmetric synthesis of β-lactones via an NHC-catalysed formal [2+2] cycloaddition of alkylarylketenes and chloral. This process operated in good yield (typically >70%) and moderate diastereoselectivity (typically ~75:25 dr, anti:syn) for a range of alkylarylketenes. The enantioselectivity was consistently high for the major anti diastereomer (typically >80% ee) and minor syn diastereomer (typically >70% ee). Interestingly, when a ketene bearing a 2 substituent on the aryl ring, or one that included an α-branched alkyl group was used, an exclusive asymmetric chlorination pathway was accessed. This is, to the best of our knowledge, the first use of chloral as an electrophilic chlorination agent. This methodology was found to be applicable to a range of 2-arylsubstituted alkylarylketenes in good yield and enantioselectivity (typically >70% yield and up to 92% ee). The scope of this reaction with respect to the aldehyde moiety was then analysed with 2-nitrobenzaldehyde providing β-lactone products in excellent dr (up to 94:6 syn:anti) and with good yield and enantioselectivity (typically >60% yield and >80% ee). Importantly these β-lactone products were amenable to further derivatisation with transformation to β-amino- and β-hydroxy acids. Following the identification of an NHC-catalysed chlorination reaction using chloral, the development of a general procedure was undertaken. Following a wide screen of electrophilic chlorination sources, 2,3,4,5,6,6 hexachlorocyclohexa 2,4 dienone was identified as optimal, operating in excellent yield (up to 97%) but in moderate to poor levels of enantioselectivity (21−61% ee). Efforts to expand the practicality of azolium enolate processes focused on the use of α-aroyloxyaldehydes as bench stable mono-substituted ketene surrogates. A range of differentially substituted α-aroyloxyaldehydes allowed access to δ-lactones via the NHC-catalysed [4+2] cycloaddition between azolium enolates and β,γ unsaturated α ketoesters. Following initial optimisation the reaction proceeded in exquisite diastereo- and enantiocontrol (typically >95:5 dr and >99% ee).
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The art of union and disunion in the Houses of Parliament, 1834-1928Ford, James January 2016 (has links)
This thesis explores the importance of the United Kingdom’s composition as a multinational state to the decoration of the new Houses of Parliament, constructed by Sir Charles Barry following the destruction of most of the old Palace of Westminster by fire in 1834. Over seven chapters, it examines the decorative schemes undertaken between the 1840s and 1860s by Barry and the Fine Arts Commission, followed by later, individual programmes, the last of which was completed in 1928. This study develops the twin notions of the art of union and the art of disunion to analyse the complex relationship between the Union and Parliament’s decorative schemes. The art of union is used to identify the elements of the New Palace of Westminster’s planned or completed decoration that validated and promoted the Union. Meanwhile, the art of disunion is deployed as a means of analysing the works of art that caused disunity and division. Examples of the art of union in the Houses of Parliament have led to it being described as a very British building. However, this thesis argues that this is an inadequate description. Though Scotland, Ireland and Wales are represented in the building’s decoration, it is England that dominates. Therefore, this study argues that Anglo-British is the most accurate term with which to describe the sense of national identity embodied by the Palace of Westminster. However, the Anglo-Britishness presented over the lengthy period covered in this thesis is not a consistent and homogenous vision, but one that is varied, complex and, at times, contradictory. There is also a clear development in the general form that it takes: beginning with a relatively inclusive Anglo-Britishness that gives some recognition to the UK nations other than England, it becomes increasingly Anglocentric and imperialist over the period examined.
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An analysis of the acquisition process of the Joint Fires Network/Tactical Exploitation System-NavyLeyland, Patricia E. 06 1900
Approved for public release, distribution is unlimited / There is a growing movement throughout the Department of Defense (DoD) towards the implementation of Network Centric Warfare (NCW). In an effort to transition to NCW, the Navy has fielded many different technologies. One system exploiting new technologies in the Intelligence, Surveillance, and Reconnaissance (ISR) domain is the Joint Fires Network/Tactical Exploitation System-Navy (JFN/TES-N), which was developed from the Army Tactical Exploitation System, (TES-A). This system was developed rapidly and uniquely for fleet deployment in accordance with the interim acquisition guidance signed by the Honorable Paul Wolfowitz. This guidance authorized Evolutionary Acquisition following a Spiral Development process in lieu of the "traditional" cold war process described in the DoD 5000 series publications. Assuming that (JFN/TES-N) will be viewed as a successful acquisition, several Navy personnel have stated that it may become the model for future C4I (and other) system acquisitions. This thesis seeks to help develop that model. The objectives of this thesis are: ʺ To examine whether the TES-N acquisition process is an appropriate model of Evolutionary Acquisition following a Spiral Development. ʺ To identify and make recommendations for changes or improvements to the TES-N acquisition program, so it can be used as a more appropriate model for Evolutionary Acquisition following a Spiral Development. This thesis concludes that Evolutionary Acquisition following a Spiral Development shown with the JFN/TES-N system is an acquisition policy that is appropriate for programs of the same size and scope, but larger more complex programs will not have as much success. Yet, in order for the JFN/TES-N program and future programs using Evolutionary Acquisition following a Spiral Development to succeed, changes have to be made in policies such as budgetary submissions, test and evaluation, policy, process, and training. / Ensign, United States Navy
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Réactivités de N-Tosylhydrazones : application à la Synthèse d’Analogues de l’isoCombrétastatine A-4 / N-Tosylhydrazones : towards the synthesis of isocombretastatin A-4 analoguesAziz, Jessy 24 November 2014 (has links)
Les travaux rapportés dans ce mémoire concernent le développement de la réactivité de N-tosylhydrazones dans la création de liaisons carbone-carbone et carbone-azote ainsi que leurs applications à la synthèse des analogues de l’isocombrétastatine A-4 (isoCA-4), aux propriétés antivasculaires.Au cours de ce travail, des molécules de type 1,1-diaryléthylène furent synthétisées par un couplage pallado-catalysé entre des N-tosylhydrazones et des aryles halogénés. Ainsi, des oléfines polysubstituées avec un motif alcoxyle, analogues de l’isoCA-4, ont présenté des activités biologiques intéressantes. De même, les N-tosylhydrazones constituent des intermédiaires pour la synthèse de 1,5-énynes aromatiques. La cyclisation de ces derniers a pu être contrôlée selon la nature du catalyseur utilisé. En effet, en présence de l’or comme catalyseur, une cyclisation 6-endo-dig majoritaire est obtenue alors qu’en présence du palladium, une cyclisation 5-exo-dig exclusive est observée. Cette méthode permettrait de synthétiser des analogues contraints de l’isoCA-4. Le couplage réducteur, catalysé au cuivre, entre des N-tosylhydrazones et des amines et conduisant à des motifs arylalkylamines fut développé. Enfin, un processus cascade entre des 2’-halogéno-biaryl- N-tosylhydrazones et des amines fournit des dérivés du fluorène par la création d’une liaison CN et d’une liaison CC sur le même atome carbénique. / This manuscript reports the development of new metal-catalyzed reactions using N-tosylhydrazones as coupling partners for the creation of carbon-carbon and carbon-nitrogen bonds. These reactions are applied in the synthesis of analogues of isocombretastatine A-4 (isoCA-4), a vascular disrupting agent.First, a palladium-catalyzed cross-coupling reaction between N-tosylhydrazones and aryl halides was developed. By this means, polysubstituted olefins with an alkoxy motif were synthesized and presented good biological activities. Then, aromatic 1,5-enynes were synthesized by a multi-step approach using N-tosylhydrazones as intermediates. The regioselectivity of the cyclisation of these enynes was controlled depending on the reaction conditions. Under gold catalysis, a major 6-endo-dig cyclisation pattern leads to naphthalene derivatives while under palladium catalysis; an exclusive 5-exo-dig cyclisation furnishes benzofulvène derivatives. Conformationnally restricted isoCA-4 analogues could be synthesized by applying this method. A copper-catalyzed reductive coupling between N-tosylhydrazones and amines leading to -branched amine derivatives was also developed. Finally, a cascade reaction between 2’-halo-biaryl-N-tosylhydrazones and amines furnished fluoren scaffold by the formation of CC and CN bonds on the same carbenic atom.
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A master's thesis consisting of a proposed acting project: Starbuck in The Rainmaker by N. Richard Nash and an analysis of a performed major role: John in Judith by Jean GiraudouxPeterson, Paul Warren January 1963 (has links)
Thesis (M.F.A.)--Boston University
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Conversão do Cerrado em pastagem e sistemas agrícolas: efeitos na dinâmica da matéria orgânica do solo / Brazilian savanna conversion to pastures and agricultural systems: effects in the soil organic matter dynamicsFrazão, Leidivan Almeida 31 August 2007 (has links)
A mudança de uso da terra no Cerrado acarreta em alterações na dinâmica da matéria orgânica do solo (MOS). Práticas de manejo com revolvimento das camadas de solo aceleram a decomposição da MOS, favorecendo as emissões de gases do efeito estufa do solo para atmosfera. Dessa forma, o objetivo desse trabalho foi avaliar as mudanças na dinâmica da MOS de um Neossolo Quartzarênico submetido a diferentes usos e sistemas de manejo, utilizando como referência o sistema nativo (Cerrado). O presente estudo foi realizado no município de Comodoro - MT (13º50\'00\" a 13º50\'03\" S e 59º37\'18\" O). Foi empregado o delineamento experimental inteiramente casualizado com sete áreas de estudo. As coletas foram realizadas em julho de 2005 e fevereiro de 2006 e as áreas amostradas foram: Cerrado nativo (CER); pastagem (CAP22); plantio convencional com a cultura da soja (CS1), sucessão de culturas arroz-soja (CAS3) e sucessão arroz-soja-sorgo ou milheto (CAS/Sor3 e CAS/M3); e plantio direto (CAP13S/M5). Foram estudadas as seguintes variáveis: atributos físicos e químicos do solo, estoques de carbono (C) e nitrogênio (N) do solo, teores de C e N nas frações granulométricas da MOS, quantidades de N inorgânico, C e N microbiano do solo, quociente metabólico (qCO2) e fluxos de gases do solo (CO2, N2O e CH4). Os resultados deste estudo indicaram que os sistemas com plantio convencional e plantio direto avaliados apresentaram melhoria nos atributos físicos e químicos do solo em relação a pastagem (CAP22), com menor compactação do solo e aumento na disponibilidade de fósforo, cálcio e magnésio. Foram obtidos maiores estoques de C e N em CAS/Sor3 e CAS/M3, áreas com maiores teores de argila. A área CAP13S/M5 também mostrou maiores teores de argila, porém baixos estoques de C e N, resultado atribuído ao uso da terra por treze anos com pastagem sem reforma e ao pouco tempo de implantação do sistema plantio direto. Analisando as frações granulométricas da MOS verificou-se maiores teores de C e N na fração menor que 50 \'mü\'m. As maiores quantidades de N inorgânico em relação ao CER foram observados na área CAS/M3, e com exceção desta área, a forma predominante de N inorgânico foi o amônio. Foram obtidas maiores quantidades de C e N microbiano na época úmida, quando todas as áreas estavam com cobertura vegetal. Entre as áreas de estudo, as maiores quantidades de C e N microbiano foram obtidos em CAP22. Os fluxos de C-CO2, com exceção da área CAS/Sor3, foram maiores na época úmida, enquanto que os fluxos de N-N2O e C-CH4 foram semelhantes entre as épocas de estudo. Os fluxos de gases em C equivalente não apresentaram diferenças significativas entre as áreas de estudo devido ao alto desvio padrão verificado para cada gás. A mudança de uso da terra promove alterações na dinâmica da MOS, porém neste estudo não foi possível distinguir qual o melhor sistema de uso para o Neossolo Quartzarênico devido ao pouco tempo de implantação dos sistemas plantio convencional e plantio direto, e a degradação da pastagem (apesar do maior tempo de implantação) / Land-use changes of Brazilian savanna (Cerrado) result in alterations of the soil organic matter (SOM). Managements practices with tillage accelerate the SOM decomposition, enhancing greenhouse gases emissions from the soil to the atmosphere. Therefore, the objective of this work was to evaluate the changes in the SOM dynamics of a Typic Quartzipisamment submitted to different uses and managements systems, using as reference the native system (Cerrado). The present study was conducted in areas located at Comodoro (Mato Grosso state, Brazil) (from 13º50\'00\" till 13º50\'03\" S and 59º37\'18\" W). At each site, samples were taken randomly within seven areas. Sampling activities were performed in July 2005 and February 2006 and the sample sites consist of an area of \"Cerrado\" (CER); pasture (CAP22); conventional tillage with soybean (CS1), rice-soybean succession (CAS3) and rice-soybean-sorghum or millet (CAS/Sor3 and CAS/M3) successions; and a field with no-tillage system (CAP13S/M5). Studied variables were: physical and chemical attributes, C and N stocks, isotopic composition of 13C/12C and 15N/14N, C and N content in the SOM fractions, quantity of inorganic N, microbial C and N biomass, metabolic quotient (qCO2), and the soil gases fluxes (CO2, N2O and CH4). The results of this study showed that all evaluated fields under conventional or no-tillage systems result in physical and chemical attribute improvement in relation to the pasture (CAP22), with soil compaction decrease, pH increase and improvement of the availability in phosphorus, calcium and magnesium. The C and N stocks were higher in areas CAS/Sor3 and CAS/M3, corresponding to the highest clay content. The area CAP13S/M5 showed similar clay content, but smaller C and N stocks, this result was attributed to the land-use: thirteen years as pastures without reform and also the short time of no-tillage implantation. Analyzing the SOM fractions, it was verified higher C and N contents in the 50 \'mü\'m fraction. The higher quantities of inorganic N in relation to the CER were found in area CAS/M3, and with exception of this area, ammonium was the predominant form of inorganic N. Higher quantities of the microbial C and N were obtained during the wet season, when all areas presented a cover crop. Among areas, the higher quantities of microbial C and N were obtained in CAP22. The fluxes of C-CO2, excepting area CAS/Sor3, were higher during the wet season, while the fluxes of N-N2O and C-CH4 were similar between seasons studied, because high standard deviations were calculated for each gas. The land use promoted alterations in SOM dynamic, however it was not possible to differentiate the best land use for this Typic Quartzipisamment, mainly due to the short time of no-tillage implantation, and the degradation of the pasture (although of the implantation time was higher)
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Untersuchungen zur Erfassung der Nitratverlagerung und Stickstoffkonservierung während des Winters in Abhängigkeit von der Bodenbearbeitung, Bodenbedeckung und N-DüngungSchumann, Martin 30 November 2005 (has links)
Im Rahmen eines vierjährigen Feldversuches wurden der Einfluss von Bodenbearbeitung, Bodenbedeckung und Stickstoffdüngung auf die N-Dynamik und N-Verlagerung während der Winterhalbjahre und deren Nachwirkungen auf die Hauptfrucht der nachfolgenden Vegetationsperiode untersucht. Es zeigte sich, dass sich neben den Prüffaktoren auch Unterschiede der Vorfrucht und des Witterungsverlaufes auf die Höhe der Nitratauswaschung über Winter auswirkten. Generell führte der Anbau von Winterrübsen gegenüber der Brache erwartungsgemäß zu einer Reduzierung des N-Austrages, was sowohl auf die geringeren Sickerwassermengen als auch auf die geringeren Nitratkonzentrationen in der Bodenlösung zurückzuführen war. Die N-Konservierung der Winterrübsen wirkte sich auf die folgende Hauptfrucht positiv hinsichtlich der Stickstoffverfügbarkeit im Oberboden und der N-Aufnahme des Sommerweizens während dessen Standzeit aus. Der Schwerpunkt in der methodischen Vorgehensweise dieser Arbeit lag in der Erfassung der Sickerwassermengen zur Abschätzung der N-Verlagerung anhand der Daten der Nitratkonzentration in der Bodenlösung. Die Durchflussmengen im Boden wurden ausgehend von der klimatischen Wasserbilanz und unter Berücksichtigung der Veränderungen der Bodenwasservorräte bestimmt, die anhand von Messungen der Matrixpotentiale und der Kenntnis der Bodenwassercharakteristika im Profilverlauf des Bodens berechnet wurden. Dieser Ansatz wurde drei weiteren Ansätzen gegenübergestellt. Diese sind die klimatische Wasserbilanz, die klimatische Wasserbilanz unter Berücksichtigung der Veränderungen der Bodenwasservorräte anhand der volumetrischen Wassergehaltsmessung mit Hilfe der TDR-Messtechnik und die Bestimmung der Perkolation mittels Wasserleitfähigkeitsfunktionen und Potentialgradienten. Mögliche Fehlerquellen der verschiedenen Ansätze wurden diskutiert und Schlussfolgerungen für die praktische Versuchsdurchführung gezogen. / The influence of different tillage managements, soil covering and different nitrogen applications on the N-dynamic and N-leaching during winter and their effects during the following vegetation period have been investigated within the scope of a field trial of several years. Beside these treatments, differences of the preceding crop type and climatic conditions showed also effects on the amount of nitrate leaching during winter. The cultivation of winter rape compared to fallow reduced the N-leaching in accordance with the expectations; generally this was the result of lower rates of water flow as well as lower nitrate concentrations in the soil solution. During the successive vegetation periods the N-conservation by the catch crop led to higher nitrate contents in the soil, particularly in the upper layer, and to an increasing N-uptake of the fallowing spring wheat. Focal point of the methodical proceeding of this study was the recording of the downward water movement to estimate the N-leaching in combination with the nitrate concentration in the soil solution. The calculation of the water movement in the soil based on the climatic water balance in consideration of the variation of the soil water content; the changes in the soil water were determined by data of the soil matrix potential and the knowledge of the moisture characteristics of the horizons, their positions and their wideness. This approach was based to present the results, and was then compared with three other ones. These were the climatic water balance, the climatic water balance in consideration of the variation of the soil water content by data of the changes of the volumetric soil water content measured by ‘time domain reflectrometry’ and the calculation of water flow with hydraulic conductivity functions and data of the hydraulic potentials. Possible sources of error of the methods are discussed to draw conclusions for conducting field trials.
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Triptamina e dimetiltriptamina em melanomas: biossíntese, metabolização e atividades antitumorais / Tryptamine and dimethyltryptamine on melanomas: biosynthesis, metabolism and antitumor activityCoimbra, Janine Baptista 27 July 2012 (has links)
O metabolismo do triptofano (TRP) se dá por três vias metabólicas: a via das quinureninas, a via serotonérgica e a via das triptaminas. A primeira gera quinurenina e uma gama de produtos secundários e contribui para os fenômenos de tolerância e imunoescape de células tumorais. A via serotonérgica leva à produção de neuromediadores e pode gerar melatonina. Há evidências de que compostos desta via podem controlar o crescimento tumoral. A via das triptaminas origina triptamina (TRY) e N-N-dimetiltriptamina (DMT) e representa a rota menos conhecida de degradação do TRP. Assim, investigamos a via das triptaminas em linhagens de melanoma humano SK-Mel-19 e SK-Mel-147. A expressão gênica das enzimas aminoácido aromático descarboxilase (DDC) e indoletilamina-N-metiltransferase (INMT), que convertem o TRP em TRY e DMT, respectivamente, foi determinada por PCR em tempo real. Os metabólitos desta via foram detectados por LC/MS no sobrenadante das culturas celulares. O teste da ferida (scratch test) e o ensaio clonogênico foram usados a fim de triar uma possível atividade antitumoral de TRY e DMT. Apesar de termos observado a expressão das enzimas DDC e INMT apenas na linhagem SK-Mel-147, ambas produziram triptaminas e metabolizaram TRY e DMT. Dependendo da linhagem houve a produção de ácido indolacético, DMT hidroxilado e produtos de abertura do anel indólico. Por fim, TRY e DMT diminuíram a migração e a proliferação das células tumorais. Há ainda muito a se estudar sobre a participação da TRY e DMT na biologia do tumor e as nossas descobertas ampliam o papel do metabolismo do triptofano no processo tumoral. / Tryptophan (TRP) metabolism occurs by three pathways: kynurenine, serotonergic and tryptamines paths. The first generates kynurenine and a range of secondary products and contributes to tolerance and tumor immune escape. Serotonergic pathway leads to the production of neuromediators and can generate melatonin. There are evidences that compounds of this pathway may control tumor growth. Tryptamines pathway originates tryptamine (TRY) and N, N-dimethyltryptamine (DMT) and represents the less-known route of TRP degradation. Thus, we investigated tryptamines pathway on human melanoma cell lines SK-Mel-19 and SK-Mel-147. Gene expression of the enzymes aromatic amino acid decarboxylase (DDC) and indoletilamina-N-methyltransferase (INMT), which convert TRP to TRY and DMT, respectively, was determined by real time PCR. The metabolites of this pathway were detected by LC/MS in cell culture supernatant. The scratch test and clonogenic assay were used to screen a potential antitumor activity for TRY and DMT. Although we have observed the expression of the enzymes DDC and INMT only on SK-MEL-147, both cells produced tryptamines and metabolized TRY and DMT. Depending on the cell line, products were indoleacetic acid (IAA), hydroxylated-DMT (OH-DMT) and indole opening ring products. Finally, TRY and DMT decreased tumor cells migration and proliferation. There is much to be studied about the participation of TRY and DMT in tumor biology, and our findings extend the role of tryptophan metabolism in tumoral process.
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