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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Modification d’acides aminés et de protéines en milieux aqueux sous faisceau d'ions / Amino acids and proteins modification under ion beams in aqueous medium

Ludwig, Nicolas 12 October 2018 (has links)
Cette thèse s’inscrit dans une volonté d’améliorer la compréhension des mécanismes fondamentaux de radiolyse de biomolécules par des ions accélérés, à l’échelle moléculaire. Ainsi, les ions étudiés ont été de différentes nature (H+, He2+, C6+) et de différentes énergies, correspondant à une gamme de densité de dépôt d’énergie allant de 0,3 à 1000 eV/nm.Dans le vivant, l’eau ayant une place prépondérante, la compréhension de la radiolyse de l’eau est essentielle. L’espèce la plus réactive produite en milieu aéré, le radical hydroxyle (HO•) a été quantifiée en utilisant une sonde spécifique, l’acide 3-coumarine-carboxylique.Les dégâts indirects aux biomolécules, via les espèces issues de la radiolyse de l’eau, ont été étudiés en solution aqueuse diluée sur deux systèmes : un acide aminé, la phénylalanine et une protéine, la myoglobine. Les effets directs de radiolyse ont été étudiés sur la myoglobine en gels concentrés hydratés. Les phénomènes de radiolyse ont été caractérisés pour décrire les mécanismes en jeu et les produits issus de la radiolyse de la phénylalanine ont été systématiquement identifiées et quantifiées. / The goal of this thesis is to achieve a better understanding of fundamental mechanisms of the radiolysis of biomolecules by accelerated ions, at the molecular scale. To do so, different type of ions have been used (H+, He2+, C6+) at various energies, corresponding to densities of energy deposition from 0,3 to 1000 eV/nm.The main component in biological systems is water. Therefore, the comprehension of the water radiolysis under ions irradiation is essential. One of the most reactive species produced in aerated conditions, the hydroxyl radical (HO•), has been quantified using a specific probe, the 3- carboxylic acid coumarin.Indirect effects of radiolysis on biomolecules, involving water radiolysis species, have been studied in dilute aqueous solutions on two different systems: phenylalanine, an amino acid, and a protein, myoglobin. Direct radiolysis effect were studied on concentrated hydrogels of myoglobin ad other proteins. Elucidation of radiolysis mechanisms and quantification of phenylalanine radiolysis products were systematically performed.
92

Avaliação de parâmetros do metabolismo de carbono e nitrogênio e de respostas ao estresse na associação de trigo com a bactéria Herbaspirillum seropedicae / Evaluation of carbon and nitrogen metabolism parameters and responses to stress in wheat association with bacteria Herbaspirillum seropedicae

Ortolan, Sarah Romani 28 July 2015 (has links)
Made available in DSpace on 2017-07-10T17:37:10Z (GMT). No. of bitstreams: 1 Sarah_Romano_Ortolan.pdf: 975526 bytes, checksum: d72ab61fc7bdc88b6ddbab0eb3a86e42 (MD5) Previous issue date: 2015-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Wheat is considered the main cereal diet of the world population, but in recent years has achieved some gain in productivity of this culture despite having increased the use of nitrogen fertilizer. The use of plant growth promoting bacteria such as Herbaspirillum seropedicae SmR1 among others has been studied to obtain development of plants with less use of nitrogen fertilizers. However there is little information relating the effects of this interaction in plant development and grain yield. Objective of this study was to evaluate the carbon and nitrogen metabolism by certain enzymes, metabolites and indices related to the response to infectious stress on the wheat cultivars CD 104 and CD 120 in association with Herbaspirillum seropedicae bacteria. Two experiments were conducted. The experimental design was completely randomized with four replications in a 4x2. The first factor relates to the conditions inoculation with bacteria and/or nitrogen source in coverage are: control without inoculation with bacteria or added nitrogen fertilizer (C); application of nitrogen fertilizer (50 kg.ha-1) 30 days after sowing (N); inoculation with 106 cells of the bacterium H. seropedicae/seed at planting (Hs) and inoculation with bacteria combined with the application of nitrogen fertilizer (Hs + N) and the second factor refers to the phenological stages (tillering and booting). The results indicated that inoculation with H. seropedicae in wheat seeds of cv.s CD 104 and CD 120 in the two growth stages answered in relation to the indices related to stress with the involvement of enzymes of carbon and nitrogen metabolism. However prominent effect was not noticed to promote plant growth of wheat in late development, nor a deleterious effect of the bacterium for inoculation cv. CD 104 under the experimental conditions. For cv. CD 120 the differential effects indicate lower levels of stress and some level of association to positive effect on productivity when combined inoculation of bacteria to nitrogen fertilization. It was concluded that as well as pathogenic and stressors, H. seropedicae able to beneficially associate with wheat also provides similar interference pattern of carbon and nitrogen metabolism and stress levels / O trigo é considerado o principal cereal da dieta da população mundial, entretanto nos últimos anos tem se obtido pouco ganho de produtividade desta cultura apesar de se ter aumentado o uso de fertilizante nitrogenado. O uso de bactérias promotoras do crescimento vegetal, como Herbaspirillum seropedicae SmR1 entre outras, tem sido estudado para se obter desenvolvimento de plantas com menor uso de fertilizantes nitrogenados. Entretanto existem poucas informações que relacionam os efeitos desta interação no desenvolvimento da planta e de produtividade de grãos. Objetivo deste trabalho foi avaliar o metabolismo de carbono e nitrogênio através de algumas enzimas, metabólitos e índices relacionados à resposta ao estresse infeccioso em trigo das cultivares CD 104 e CD 120 em associação com a bactéria Herbaspirillum seropedicae em dois estádios fenológicos. Foram realizados dois experimentos. O delineamento experimental utilizado foi o inteiramente ao acaso, com 4 repetições, em esquema fatorial 4x2. O primeiro fator refere-se às condições de inoculação com bactéria e/ou fertilização nitrogenada em cobertura, sendo: controle, sem inoculação com bactéria ou adição de fertilizante nitrogenado (C); aplicação de fertilizante nitrogenado (50 kg.ha-1) após 30 dias da semeadura (N); inoculação de 106 células da bactéria H. seropedicae/semente na semeadura (Hs) e inoculação com a bactéria combinada com a aplicação de fertilizante nitrogenado (Hs + N) e o segundo fator refere-se aos estádios fenológicos (perfilhamento e emborrachamento). Os resultados indicaram que a inoculação com H. seropedicae em sementes de trigo das cv.s CD 104 e CD 120 nos dois estádios fenológicos responderam em relação aos índices relacionados ao estresse com envolvimento das enzimas do metabolismo de carbono e nitrogênio. Entretanto não foi percebido efeito proeminente de promoção do crescimento vegetal no final do desenvolvimento do trigo, tampouco efeito deletério da inoculação de bactéria para a cv. CD 104, nas condições experimentais. Para a cv. CD 120 os efeitos diferenciais indicam menor nível de estresse e algum nível de associação para efeito positivo na produtividade quando combinada a inoculação da bactéria com a fertilização nitrogenada. Foi possível concluir que assim como para agentes patogênicos e estressantes, a H. seropedicae, capaz de associar beneficamente com trigo também apresenta padrão semelhante de interferência do metabolismo de carbono e nitrogênio e índices de estresse
93

Sterically flexible molecules in the gas phase

Erlekam, Undine 24 October 2008 (has links)
Für die makroskopischen Eigenschaften und Funktionen biologisch relevanter Materie spielen schwache, intra- und intermolekulare Wechselwirkungen dispersiver und elektrostatischer Natur auf molekularem Niveau eine große Rolle. Um diese schwachen Wechselwirkungen zu untersuchen, können Modellsysteme, isoliert in der Gasphase, herangezogen werden. Benzoldimer, ein schwach gebundener Van der Waals Komplex, kann beispielsweise als Modellsystem für dispersive Wechselwirkungen dienen. In der vorliegenden Arbeit werden die strukturellen Eigenschaften und die (interne) Dynamik des Benzoldimers mit Hilfe spektroskopischer Methoden in den Energiebereichen der Rotationen, Vibrationen und elektronischen Übergänge untersucht und im Kontext der Symmetrie diskutiert. Die in dieser Arbeit vorgestellten Experimente tragen zu einem tieferen Verständnis des Benzoldimers bei, jedoch zeigt das Experiment zur internen Dynamik auch, dass eine ausreichende theoretische Beschreibung des Benzoldimers nach wie vor eine Herausforderung darstellt. Schwingungsübergänge hochsymmetrischer Moleküle sind oft optisch inaktiv, können jedoch mit der hier vorgestellten Methode der Symmetrieerniedrigung durch Komplexierung zugänglich gemacht werden, wie am Beispiel des Benzols demonstriert wird. Außerdem wird ein Mechanismus vorgstellt, der kollisionsinduzierte Konformationsänderungen in einem Molekularstrahl beschreibt. Dieses Modell kann generell für Molekularstrahlexperimente an flexiblen Molekülen hilfreich sein, einerseits um die beobachtete Konformationsverteilung zu verstehen, andererseits um die experimentellen Parameter gezielt zu verändern und somit Konformerpopulationen zu manipulieren. Die in dieser Dissertation vorgestellten spektroskopischen Experimente liefern einerseits molekülspezifische Informationen und ermöglichen andererseits, Modelle, die von allgemeiner Bedeutung sind, zu entwickeln. / The macroscopically observable properties and functionalities of biological matter are often determined by weak intra- and intermolecular interactions on the microscopic level. Such weak interactions are for example hydrogen bonding and van der Waals interactions and can be investigated best on isolated model systems in the gas phase. The benzene dimer, for example, is a prototype system to investgate dispersive interactions. The spectroscopic experiments, covering the energy ranges of rotations, vibrations and electronic transitions, presented in this thesis, contribute to a deeper understanding of the benzene dimer. However, from the experiments investigating the internal dynamics it becomes clear that an appropriate theoretical description of the benzene dimer is still a challenge. Vibrational transitions of highly symmetric molecules, as for example of the benzene, are often optically inactive. Here, a method is presented, which exploits symmetry reduction upon complexation and thus allows one to access such modes. Furthermore, a model is proposed describing collision induced conformational interconversion in a molecular beam. This model can be helpful for molecular beam experiments of flexible molecules to understand the observed relative conformational population and to adapt the experimental conditions allowing for the manipulation of the relative conformer abundances. In this thesis, results are presented that allow one on the one hand to deduce molecular specific information and that on the other hand also give a broader insight into phenomena of general importance.
94

Influência do glyphosate no perfil bioquímico e fisiológico de populações de azevém (Lolium multiflorum) suscetíveis e resistentes ao herbicida / Glyphosate influence in the biochemical and physiological profile of susceptible and resistant ryegrass (Lolium multiflorum) populations to herbicide

Picoli Junior, Gilmar José [UNESP] 25 January 2016 (has links)
Submitted by GILMAR JOSÉ PICOLI JUNIOR null (gilmarpicoli@yahoo.com.br) on 2016-03-01T21:07:14Z No. of bitstreams: 1 Tese versão definitiva.pdf: 3101518 bytes, checksum: 929d40efab9e6e768e639133eb923580 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-04T12:31:13Z (GMT) No. of bitstreams: 1 picolijunior_gj_dr_bot.pdf: 3101518 bytes, checksum: 929d40efab9e6e768e639133eb923580 (MD5) / Made available in DSpace on 2016-03-04T12:31:13Z (GMT). No. of bitstreams: 1 picolijunior_gj_dr_bot.pdf: 3101518 bytes, checksum: 929d40efab9e6e768e639133eb923580 (MD5) Previous issue date: 2016-01-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No Brasil, o azevém (Lolium multiflorum) foi identificado como resistente ao glyphosate se tornando um grande problema em determinadas lavouras. Dessa forma, entender o comportamento a nível bioquímico e fisiológico desta planta daninha são ferramentas que auxiliam num manejo eficiente. Com isso, o objetivo deste trabalho foi comparar o perfil bioquímico e fisiológico de populações de azevém suscetíveis e resistentes ao herbicida glyphosate aplicação do mesmo. Foram realizados quatro estudos em casa-de-vegetação com delineamento experimental inteiramente casualizados com quatro repetições sendo semeadas três populações de azevém (Lolium multiflorum) consideradas como suscetível (S), com suspeita de resistência (R1) e resistente (R2) ao herbicida glyphosate. No primeiro estudo foi obtido o controle aos 21 dias após a aplicação (DAA) e quantificada a massa seca aos 28 DAA das três populações. Os tratamentos foram constituídos da aplicação do herbicida glyphosate composto pelas doses: 0, 135, 270, 540, 1080, 2160, 4320, 8640 g e.a. ha-1. O segundo estudo teve como objetivo determinar a atividade da enzima fenilalanina amônia liase (PAL) nas diferentes populações as 12, 24, 48 e 72 horas após a aplicação (HAA). Os tratamentos foram compostos de duas doses (720 g e.a. ha-1 e 1080 g e.a. ha-1) mais uma testemunha sem aplicação. No terceiro estudo foram realizadas avaliações da fotossíntese nas três populações ao 1, 3, 7 e 28 DAA. As variáveis analisadas foram: taxa de assimilação líquida de CO2, condutância estomática, concentração interna de CO2, transpiração, eficiência do uso da água e eficiência instantânea de carboxilação. Os tratamentos foram compostos de duas doses (720 g e.a. ha-1 e 1080 g e.a. ha-1) mais uma testemunha sem aplicação. O quarto estudo teve o objetivo de quantificar compostos alterados da rota do ácido chiquímico. Para isso, foram utilizados os mesmos tratamentos do primeiro estudo e realizadas coletas das folhas aos 5, 11 e 28 DAA. Os compostos analisados foram: glyphosate, AMPA (ácido aminometilfosfônico), ácido chiquímico, ácido quínico, shiquimato-3-fosfato, os aminoácidos aromáticos fenilalanina, tirosina e triptofano, ácido ferúlico, ácido coumárico e ácido cafeico. Na população considerada resistente, a atividade da enzima fenilalanina amônia liase manteve-se alta após a aplicação do glyphosate. Todas as variáveis fisiológicas foram afetadas após a aplicação do glyphosate nas três populações, porém, R2 foi capaz de se recuperar apresentando valores semelhantes à testemunha. Os níveis de ácido chiquímico e quínico apresentaram padrões semelhantes onde houve aumento para as populações suscetíveis com o aumento da dose do herbicida enquanto que para a resistente os valores se mantiveram semelhantes. Ocorreu aumento dos níveis de shiquimato-3-fosfato para a população R2 se mantendo constante para as suscetíveis. Houve redução dos aminoácidos aromáticos com a aplicação do glyphosate para as populações suscetíveis. / In Brazil, ryegrass (Lolium multiflorum) was identified as resistant to glyphosate becoming a major problem in certain crops. Thus, understanding the behavior of the biochemical and physiological level of this weed are tools that help in efficient management. Thus, the aim of this study was to compare the biochemical and physiological profile of ryegrass populations susceptible and resistant to glyphosate after spray it. Four studies were carried out in greenhouse with experimental design completely randomized with four replications being seeded three populations of ryegrass (Lolium multiflorum) considered as susceptible (S), suspected of having resistance (R1) and resistant (R2) to the herbicide glyphosate. In the first study was measured the control at 21 days after application (DAA) and at 28 DAA, the dry mass the three populations. The treatments consisted of application of the glyphosate composed of doses: 0, 135, 270, 540, 1080, 2160, 4320, 8640 g a.i. ha-1. The second study aimed to determine the phenylalanine ammonia lyase (PAL) activity in different populations at 12, 24, 48 and 72 hours after application (HAA). The treatments consisted of two doses (720 g a.i. ha-1 and 1080 g a.i. ha-1) plus a control without application. In the third study were carried out photosynthesis assessments at three populations at 1, 3, 7 and 28 DAA. The variables analyzed were: CO2 net assimilation rate, stomatal conductance, CO2 internal concentration, transpiration, water use efficiency and instantaneous carboxylation efficiency. The treatments consisted of two doses (720 g a.i. ha-1 and 1080 g a.i. ha-1) plus a control without application. The fourth study aimed to quantify altered compounds of the shikimic acid pathway. For this, the same treatments of the first experiment were used and made collections of leaves at 5, 11, 28 DAA. The compounds analyzed were: glyphosate, AMPA (aminomethylphosphonic acid), shikimic acid, quinic acid, shikimate 3-phosphate, the aromatic amino acids phenylalanine, tyrosine and tryptophan, ferulic acid, coumaric acid and caffeic acid. The phenylalanine ammonia lyase enzyme was not influenced by glyphosate in resitant population. All physiological variables were affected after the application of glyphosate at the three populations, but R2 was able to recover with values similar to the control. The shikimic and quinic acid levels showed similar patterns where, there was an increase for susceptible populations with increasing doses of the herbicide while in resistant, the values remained similar. There was increase in levels of shikimate-3-phosphate to the R2 population, remaining constant for susceptible. There was a reduction of the aromatic amino acids with the application of glyphosate for the susceptible populations.
95

Biologische Evaluierung von 18F-markierten Aminosäure-Tracern für Tumor- und neurologische Bildgebung

Krämer, Maximiliane-Felicia 25 November 2021 (has links)
EINLEITUNG: In der Diagnostik mittels Positronen-Emissions-Tomographie (PET) liegt ein großes Potential hinsichtlich Diagnostik und Therapie einer Vielzahl von Erkrankungen. Gerade das radioaktive Isotop 18F eignet sich aufgrund hervorragender Zerfallseigenschaften besonders gut für die Entwicklung neuer Radiotracer für den klinischen Einsatz. Dabei haben sich Aminosäure (AS)-Tracer besonders bei der Darstellung von zerebralen Tumoren bewährt. Dies ist insbesondere auf eine erhöhte AS- Transportrate sowie eine erhöhte Proteinbiosyntheserate im Tumorgewebe zurückzuführen. ZIELE DER UNTERSUCHUNGEN: Eine große Hürde in der PET-Diagnostik besteht in der Entwicklung neuer Tracer, welche sich für den klinischen Einsatz eignen. Denn auch die Qualität von PET-Untersuchungen hängt stark von der Entwicklung selektiver PET-Tracer ab. Ziel dieser Studie war es daher, die neu entwickelten Phenylalanin (Phe)-Tracer zunächst in vitro zu evaluieren, bevor die Tracer bei erfolgsversprechenden Ergebnissen in verschiedenen subkutanen sowie orthotopen Tumormodellen in vivo eingesetzt wurden. Ein besonderes Augenmerk wurde auf die Entwicklung neuer Tracer für die Darstellung zerebraler Glioblastome gelegt, da diese nach wie vor meist zu einem späten Erkrankungszeitpunkt diagnostiziert werden und mit einer hohen Mortalität einhergehen. TIERE, MATERIAL UND METHODEN: Insgesamt 5 Tracer – 3-L-[18F]FPhe, 3-D-[18F]FPhe sowie α-Methyl-2-,3- und 4-[18F]FPhe – wurden hinsichtlich ihrer Bildeigenschaften im PET evaluiert. Als Referenztracer wurde jeweils der bereits etablierte Tracer [18F]Fluoroethyltyrosin ([18F]FET) eingesetzt. Zunächst wurde die prinzipielle Eignung der Tracer anhand von in vitro Zellaufnahmeversuchen an verschiedenen humanen Tumorzelllinien (MCF-7, PC-3 und U87 MG) evaluiert. Erste in vivo Versuche zur Biodistribution wurden an gesunden weiblichen und männlichen Ratten (Long Evans, je n=6) durchgeführt. Im Anschluss erfolgten Untersuchungen an einem subkutanen Tumormausmodell (männliche SCID-Mäuse, n=18) sowie einem orthotopen Gehirntumormodell an der Ratte (männliche RNU-Ratten, n=24). ERGEBNISSE: Die in vitro Traceraufnahme der evaluierten Phe-Tracer war höher oder ähnlich im Vergleich zu [18F]FET. Vor allem das AS-Transportsystem L sowie ASC waren am Transport der AS-Tracer beteiligt. Eine Proteininkorporation konnte für den Tracer 3-L-[18F]FPhe nachgewiesen werden. Insgesamt zeigten alle Tracer eine hohe metabolische Stabilität in gesunden Tieren in vivo. Die höchste Gehirnaufnahme wurde für die Tracer 3-L-[18F]FPhe, 3-D-[18F]FPhe sowie αM-3-[18F]FPhe beobachtet. Im subkutanen Tumormodell wiesen alle Tracer ähnliche Tumorbildgebungseigenschaften auf. Lediglich αM-2-[18F]FPhe zeigte in den MCF-7 Tumoren signifikant niedrigere Tumorwerte im Vergleich zu [18F]FET. Auch im orthotopen Modell war zu beobachten, dass sich die neuen Phe-Tracer nur geringgradig von [18F]FET unterschieden. Hier zeigten sich in den ersten Minuten post injectionem (p.i.) signifikant höhere Traceraufnahmen für 3-L-[18F]FPhe sowie αM-3-[18F]FPhe im orthotopen Glioblastom. Das Tumor/Gehirn-Verhältnis zeigte jedoch keine signifikanten Unterschiede hinsichtlich der untersuchten Tracer. SCHLUSSFOLGERUNGEN: Insgesamt wiesen alle fünf evaluierten Tracer gute Tumorbildgebungseigenschaften auf. Die Enantiomere 3-L-[18F]FPhe und 3-D-[18F]FPhe unterschieden sich erstaunlicherweise kaum in ihrem biologischen Verhalten. Insbesondere für die Tracer 3-L-[18F]FPhe sowie αM-3-[18F]FPhe war eine hohe Tumortraceraufnahme zu beobachten. Alle Tracer ermöglichten eine sensitive Detektion orthotoper Glioblastome in der Ratte. Die signifikant höhere Tumoraufnahme von 3-L-[18F]FPhe sowie αM-3-[18F]FPhe in den ersten Minuten p.i. könnte die Scanzeiten von Gehirntumorpatienten verkürzen. Eine erhöhte Proteininkorporation zeigte keinen signifikanten Vorteil für 3-L-[18F]FPhe gegenüber [18F]FET. Insgesamt war kein klarer Vorteil gegenüber dem etablierten AS-Tracer [18F]FET zu sehen.:1. EINLEITUNG 2. LITERATURÜBERSICHT 2.1 Prinzip der Positronen-Emissions-Tomographie 2.2 Klinische Bedeutung von Phenylalanin. 2.3 Vor- und Nachteile Aminosäure-basierter PET-Tracer 2.4 Wichtige eingesetzte PET-Tracer in der zerebralen Tumorbildgebung 2.4.1 L-[methyl-11C]methionin ([11C]MET) 2.4.2 [11C]-α-Methyl-L-Tryptophan ([11C]AMT) 2.4.3 6-[18F]Fluor-L-3,4-dihydroxyphenylalanin ([18F]FDOPA) 2.4.4 [18F]Fluorethyltyrosin ([18F]FET) 2.5 Blut-Hirn-Schranke: Aufbau und tierartliche Unterschiede 2.5.1 Aufbau der Blut-Hirn-Schranke 2.5.2 Transport über die Blut-Hirn-Schranke 2.5.3 Tierartliche Unterschiede 2.5.4 Einfluss von Krankheiten auf die Blut-Hirn-Schranke 2.6 Aminosäurentransporter: Charakterisierung und Vorkommen in verschiedenen Tumorarten 2.6.1 Aminosäurentransportsystem L 2.6.1.1 LAT1/SLC7A5-Transporter 2.6.2 Aminosäurentransportsystem ASC 2.6.2.1 ASCT2/SLC1A5-Transporter 2.6.3 Aminosäurentransportsystem A 3. TIERE, MATERIAL UND METHODEN 3.1 Haltung der Versuchstiere 3.1.1 Haltung der Versuchsratten 3.1.2 Haltung der Versuchsmäuse 3.2 Anästhesie der Versuchstiere 3.3 Verwendete Materialien und Geräte 3.4 Verwendete Agenzien 3.5 Herstellung der 18F-markierten Tracer 3.5.1 Physikalische Grundlagen 3.5.2 Herstellung des radioaktiven Isotops 18F 3.5.3 Aminosäuren-Tracer auf Phenylalanin-Basis 3.6 Verwendete Zelllinien 3.6.1 U87 MG Zelllinie (humanes Glioblastom) 3.6.2 MCF-7 Zelllinie (humanes Brustadenokarzinom) 3.6.3 PC-3 Zelllinie (humanes Prostataadenokarzinom) 3.7 Zellaufnahmeversuche in vitro 3.7.1 Zellkultivierung 3.7.2 Versuchsdurchführung der zellulären Tracer-Aufnahme 3.7.3 Versuchsdurchführung der kompetitiven Inhibitionsstudien 3.7.4 Versuchsdurchführung der Proteininkorporation 3.7.5 Messung der zellulären Tracer-Aufnahme 3.8 Biodistributionsstudien in der gesunden Ratte 3.8.1 Versuchstiere 3.8.2 Versuchsaufbau 3.9 Subkutanes Tumor-Xenograft-Modell der Maus 3.9.1 Versuchstiere 3.9.2 Verwendete Zelllinien 3.9.3 Versuchsaufbau 3.9.4 Diagnostische Verfahren 3.10 Orthotopes Tumor-Xenograft-Modell der Ratte 3.10.1 Versuchstiere 3.10.2 Verwendete Zelllinie 3.10.3 Versuchsaufbau 3.10.4 Diagnostische Verfahren 3.10.5 Transkardiale Perfusion und Gehirnentnahme nach Versuchsende 3.11 PET-Messungen 3.11.1 Rekonstruktion der PET-Bilder 3.11.2 Auswertung der PET-Bilder mit der Software VINCI 3.11.3 Biodistributionsstudien in der gesunden Ratte 3.11.4 Subkutanes Tumor-Xenograft-Modell der Maus 3.11.5 Orthotopes Tumor-Xenograft-Modell der Ratte 3.12 Statistische Auswertung 4. ERGEBNISSE 4.1 Zellaufnahmeversuche in vitro 4.1.1 Zelluläre Tracer-Aufnahme 4.1.2 Kompetitive Inhibitionsstudien 4.1.3 Proteininkorporation 4.2 Biodistributionsstudien in der gesunden Ratte 4.2.1 3-L-[18F]Fluorphenylalanin 4.2.2 3-D-[18F]Fluorphenylalanin 4.2.3 α-Methyl-2-[18F]Fluorphenylalanin 4.2.4 α-Methyl-3-[18F]Fluorphenylalanin 4.2.5 α-Methyl-4-[18F]Fluorphenylalanin 4.2.6 Vergleichende Auswertung 4.3 Subkutanes Tumor-Xenograft-Modell der Maus 4.3.1 Versuchsablauf und Gewichtsentwicklung 4.3.2 PET-Messungen MCF-7 Zelllinie 4.3.3 PET-Messungen PC-3 Zelllinie 4.3.4 Vergleichende Auswertung 4.3.5 Histologische Verfahren 4.4.1 Versuchsablauf und Gewichtsentwicklung 4.4.2 MRT- und PET-Messungen 4.4.3 Vergleichende Auswertung 4.4.4 Immunhistochemie 5. DISKUSSION 5.1 Zellaufnahmeversuche in vitro 5.2 Biodistributionsstudien in der gesunden Ratte 5.3 Subkutanes Tumor-Xenograft-Modell der Maus 5.4 Orthotopes Tumor-Xenograft-Modell der Ratte 5.5 Synopsis: Gegenüberstellung der untersuchten Tracer 5.6 Ausblick 6. ZUSAMMENFASSUNG 7. SUMMARY 8. REFERENZEN 8.1 Abbildungsverzeichnis 8.2 Tabellenverzeichnis 8.3 Formelverzeichnis 8.4 Literaturverzeichnis 9. ANHANG 9.1 Subkutanes Tumor-Xenograft-Modell der Maus 9.1.1 PET-Bilder und TACs 3-L-[18F]Fluorphenylalanin 9.1.2 PET-Bilder und TACs 3-D-[18F]Fluorphenylalanin 9.1.3 PET-Bilder und TACs α-Methyl-2-[18F]Fluorphenylalanin 9.1.4 PET-Bilder und TACs α-Methyl-3-[18F]Fluorphenylalanin 9.1.5 PET-Bilder und TACs α-Methyl-4-[18F]Fluorphenylalanin 9.1.6 PET-Bilder und TACs [18F]Fluorethyltyrosin 9.2 Orthotopes Tumor-Xenograft-Modell der Ratte 9.2.1 MRT-und PET-Bilder 3-L-[18F]Fluorphenylalanin 9.2.2 MRT-und PET-Bilder 3-D-[18F]Fluorphenylalanin 9.2.3 MRT-und PET-Bilder α-Methyl-3-[18F]Fluorphenylalanin 9.2.4 MRT-und PET-Bilder [18F]Fluorethyltyrosin 9.3 Durchführung der histologischen Verfahren 9.3.1 Hämatoxylin-Eosin-Färbung 9.3.2 Anti-LAT1(SLC7A5)-Färbung 9.3.3 Anti-ASCT2(SLC1A5)-Färbung 9.4 Statistische Auswertung 9.4.1 Zellaufnahmeversuche in vitro 9.4.2 Biodistributionsstudien in der gesunden Ratte 9.4.3 Subkutanes Tumor-Xenograft-Modell der Maus 9.4.4 Orthotopes Tumor-Xenograft-Modell der Ratte 10. DANKSAGUNG / INTRODUCTION: Positron emission tomography (PET) has gained great potential for the diagnosis and treatment of a wide range of diseases. The radioactive isotope 18F is particularly well suited for the development of new radiotracers for clinical use due to its excellent decay properties. Amino acids (AA) have proven particularly useful in the imaging of cerebral tumors due to an increased protein synthesis rate and AA transport rates in tumor tissue. AIMS OF THE STUDIES: A major difficulty in PET diagnostics is the development of new tracers which are suitable for clinical use. This is because the quality of PET imaging depends heavily on the development of selective PET tracers. The aim of the study was therefore to preclinically evaluate the newly developed phenylalanine (Phe) tracers. After principle suitability was seen in in vitro cellular experiments, further experiments were performed in subcutaneous as well as orthotopic tumor models in vivo. Particular attention has been paid to the development of new tracers imaging cerebral glioblastomas, as they are mostly still diagnosed late and are associated with high mortality. ANIMALS, MATERIAL AND METHODS: A total of 5 Phe-based tracers – 3-L-[18F]FPhe, 3-D-[18F]FPhe as well as α-Methyl-2-,3- and 4-[18F]FPhe – were evaluated with regard to their imaging properties in PET. The already established tracer [18F]fluoroethyltyrosine ([18F]FET) was used as reference tracer in each case. First, the principle suitability of the tracers was evaluated by in vitro cell uptake experiments on various human tumor cell lines (MCF-7, PC-3 and U87 MG). Next, in vivo biodistribution studies were carried out on healthy female and male rats (Long Evans, n=6). Subsequently, experiments with subcutaneous tumor bearing mice (male SCID mice, n=18) and an orthotopic brain tumor model in the rat (male RNU rats, n=24) were performed. RESULTS: The in vitro cellular uptake of the evaluated Phe-tracers was higher or similar compared to [18F]FET. Significant inhibition of cellular uptake was seen in blocking the AA transport systems L and ASC. Protein incorporation could be demonstrated for 3-L-[18F]FPhe. Overall, all tracers showed high in vivo metabolic stability in healthy animals. The highest brain uptake was observed for the tracers 3-L- [18F]FPhe, 3-D-[18F]FPhe and αM-3-[18F]FPhe. In the subcutaneous tumor model, all tracers showed similar tumor imaging properties. Only αM-2-[18F]FPhe showed significantly lower tumor levels in the MCF-7 tumors compared to [18F]FET. It was also observed in the orthotopic model that the new Phe- based tracers differed only slightly from [18F]FET. Significantly higher tracer uptakes for 3-L-[18F]FPhe as well as αM-3-[18F]FPhe were seen in the first minutes post injection (p.i.) in the orthotopic tumor. However, the tumor-to-brain-ratio showed no significant differences. CONCLUSION: All five tracers evaluated showed good tumor imaging properties. Surprisingly, the enantiomers 3-L- [18F]FPhe and 3-D-[18F]FPhe hardly differed in their biological behaviour. In particular, a high tumour tracer uptake was observed for the tracers 3-L-[18F]FPhe as well as αM-3-[18F]FPhe. All tracers enabled sensitive detection of orthotopic glioblastomas in the rat. The significantly higher tumor uptake of 3-L-[18F]FPhe and αM-3-[18F]FPhe in the first minutes p.i. could shorten the scan times of brain tumour patients. Increased protein incorporation showed no significant advantage for 3-L- [18F]FPhe over [18F]FET. In summary, no clear advantage was seen over the established AA tracer [18F]FET.:1. EINLEITUNG 2. LITERATURÜBERSICHT 2.1 Prinzip der Positronen-Emissions-Tomographie 2.2 Klinische Bedeutung von Phenylalanin. 2.3 Vor- und Nachteile Aminosäure-basierter PET-Tracer 2.4 Wichtige eingesetzte PET-Tracer in der zerebralen Tumorbildgebung 2.4.1 L-[methyl-11C]methionin ([11C]MET) 2.4.2 [11C]-α-Methyl-L-Tryptophan ([11C]AMT) 2.4.3 6-[18F]Fluor-L-3,4-dihydroxyphenylalanin ([18F]FDOPA) 2.4.4 [18F]Fluorethyltyrosin ([18F]FET) 2.5 Blut-Hirn-Schranke: Aufbau und tierartliche Unterschiede 2.5.1 Aufbau der Blut-Hirn-Schranke 2.5.2 Transport über die Blut-Hirn-Schranke 2.5.3 Tierartliche Unterschiede 2.5.4 Einfluss von Krankheiten auf die Blut-Hirn-Schranke 2.6 Aminosäurentransporter: Charakterisierung und Vorkommen in verschiedenen Tumorarten 2.6.1 Aminosäurentransportsystem L 2.6.1.1 LAT1/SLC7A5-Transporter 2.6.2 Aminosäurentransportsystem ASC 2.6.2.1 ASCT2/SLC1A5-Transporter 2.6.3 Aminosäurentransportsystem A 3. TIERE, MATERIAL UND METHODEN 3.1 Haltung der Versuchstiere 3.1.1 Haltung der Versuchsratten 3.1.2 Haltung der Versuchsmäuse 3.2 Anästhesie der Versuchstiere 3.3 Verwendete Materialien und Geräte 3.4 Verwendete Agenzien 3.5 Herstellung der 18F-markierten Tracer 3.5.1 Physikalische Grundlagen 3.5.2 Herstellung des radioaktiven Isotops 18F 3.5.3 Aminosäuren-Tracer auf Phenylalanin-Basis 3.6 Verwendete Zelllinien 3.6.1 U87 MG Zelllinie (humanes Glioblastom) 3.6.2 MCF-7 Zelllinie (humanes Brustadenokarzinom) 3.6.3 PC-3 Zelllinie (humanes Prostataadenokarzinom) 3.7 Zellaufnahmeversuche in vitro 3.7.1 Zellkultivierung 3.7.2 Versuchsdurchführung der zellulären Tracer-Aufnahme 3.7.3 Versuchsdurchführung der kompetitiven Inhibitionsstudien 3.7.4 Versuchsdurchführung der Proteininkorporation 3.7.5 Messung der zellulären Tracer-Aufnahme 3.8 Biodistributionsstudien in der gesunden Ratte 3.8.1 Versuchstiere 3.8.2 Versuchsaufbau 3.9 Subkutanes Tumor-Xenograft-Modell der Maus 3.9.1 Versuchstiere 3.9.2 Verwendete Zelllinien 3.9.3 Versuchsaufbau 3.9.4 Diagnostische Verfahren 3.10 Orthotopes Tumor-Xenograft-Modell der Ratte 3.10.1 Versuchstiere 3.10.2 Verwendete Zelllinie 3.10.3 Versuchsaufbau 3.10.4 Diagnostische Verfahren 3.10.5 Transkardiale Perfusion und Gehirnentnahme nach Versuchsende 3.11 PET-Messungen 3.11.1 Rekonstruktion der PET-Bilder 3.11.2 Auswertung der PET-Bilder mit der Software VINCI 3.11.3 Biodistributionsstudien in der gesunden Ratte 3.11.4 Subkutanes Tumor-Xenograft-Modell der Maus 3.11.5 Orthotopes Tumor-Xenograft-Modell der Ratte 3.12 Statistische Auswertung 4. ERGEBNISSE 4.1 Zellaufnahmeversuche in vitro 4.1.1 Zelluläre Tracer-Aufnahme 4.1.2 Kompetitive Inhibitionsstudien 4.1.3 Proteininkorporation 4.2 Biodistributionsstudien in der gesunden Ratte 4.2.1 3-L-[18F]Fluorphenylalanin 4.2.2 3-D-[18F]Fluorphenylalanin 4.2.3 α-Methyl-2-[18F]Fluorphenylalanin 4.2.4 α-Methyl-3-[18F]Fluorphenylalanin 4.2.5 α-Methyl-4-[18F]Fluorphenylalanin 4.2.6 Vergleichende Auswertung 4.3 Subkutanes Tumor-Xenograft-Modell der Maus 4.3.1 Versuchsablauf und Gewichtsentwicklung 4.3.2 PET-Messungen MCF-7 Zelllinie 4.3.3 PET-Messungen PC-3 Zelllinie 4.3.4 Vergleichende Auswertung 4.3.5 Histologische Verfahren 4.4.1 Versuchsablauf und Gewichtsentwicklung 4.4.2 MRT- und PET-Messungen 4.4.3 Vergleichende Auswertung 4.4.4 Immunhistochemie 5. DISKUSSION 5.1 Zellaufnahmeversuche in vitro 5.2 Biodistributionsstudien in der gesunden Ratte 5.3 Subkutanes Tumor-Xenograft-Modell der Maus 5.4 Orthotopes Tumor-Xenograft-Modell der Ratte 5.5 Synopsis: Gegenüberstellung der untersuchten Tracer 5.6 Ausblick 6. ZUSAMMENFASSUNG 7. SUMMARY 8. REFERENZEN 8.1 Abbildungsverzeichnis 8.2 Tabellenverzeichnis 8.3 Formelverzeichnis 8.4 Literaturverzeichnis 9. ANHANG 9.1 Subkutanes Tumor-Xenograft-Modell der Maus 9.1.1 PET-Bilder und TACs 3-L-[18F]Fluorphenylalanin 9.1.2 PET-Bilder und TACs 3-D-[18F]Fluorphenylalanin 9.1.3 PET-Bilder und TACs α-Methyl-2-[18F]Fluorphenylalanin 9.1.4 PET-Bilder und TACs α-Methyl-3-[18F]Fluorphenylalanin 9.1.5 PET-Bilder und TACs α-Methyl-4-[18F]Fluorphenylalanin 9.1.6 PET-Bilder und TACs [18F]Fluorethyltyrosin 9.2 Orthotopes Tumor-Xenograft-Modell der Ratte 9.2.1 MRT-und PET-Bilder 3-L-[18F]Fluorphenylalanin 9.2.2 MRT-und PET-Bilder 3-D-[18F]Fluorphenylalanin 9.2.3 MRT-und PET-Bilder α-Methyl-3-[18F]Fluorphenylalanin 9.2.4 MRT-und PET-Bilder [18F]Fluorethyltyrosin 9.3 Durchführung der histologischen Verfahren 9.3.1 Hämatoxylin-Eosin-Färbung 9.3.2 Anti-LAT1(SLC7A5)-Färbung 9.3.3 Anti-ASCT2(SLC1A5)-Färbung 9.4 Statistische Auswertung 9.4.1 Zellaufnahmeversuche in vitro 9.4.2 Biodistributionsstudien in der gesunden Ratte 9.4.3 Subkutanes Tumor-Xenograft-Modell der Maus 9.4.4 Orthotopes Tumor-Xenograft-Modell der Ratte 10. DANKSAGUNG
96

Hormone Signaling: Current Perspectives on the Roles of Salicylic Acid and Its Derivatives in Plants

Kumar, Dhirendra, Haq, Imdadul, Chapagai, Danda, Tripathi, Diwaker, Donald, David, Hossain, Mir, Devaiah, Shivakumar 14 October 2015 (has links)
Salicylic acid (SA) is an important plant hormone with a wide range of effects on plant growth and metabolism. Plants lacking SA exhibit enhanced susceptibility to pathogens. SA plays important signaling roles in resistance against biotrophic and hemi- biotrophic phytopathogens. It is synthesized in plastids along two pathways, one involving phenylalanine ammonia lyase (PAL) and the other isochorismate synthase (ICS). In Arabidopsis , during immune response most SA is synthesized through the ICS-dependent pathway, but clearly an ICS-independent pathway also exists. Several SA effector proteins have been identified and characterized which mediate downstream SA signaling. This includes SABP, a catalase, SABP2, a methyl salicylate esterase, SABP3, a carbonic anhydrase, NPR1 (nonexpressor of pathogenesis-related 1), NPR3 (a NPR1 paralog), and NPR4 (another NPR1 paralog). NPR3 and NPR4 regulate the turnover of NPR1, a process which plays a key role in activating defense gene expression. The role of SA in abiotic stress signaling is gradually becoming clearer. Various components of SA signaling in biotic stress also appear to impact abiotic stress signaling.
97

The effect of an acute phenylalanine/tyrosine depletion on reinforcement learning in humans differing in the intake of fat and sugar

Pauli, Larissa Kristin 17 November 2022 (has links)
Eine Vielzahl an Studien konnte Veränderungen dopaminerger Signale in verschiedenen Stadien von Übergewicht zeigen. Diese Veränderungen wurden mit fehlangepassten Verhaltensweisen wie zum Beispiel maladaptiven Veränderungen im Kontext von Dopamin-abhängigem Verstärkungslernen in Verbindung gebracht. Solche Verhaltensänderungen wiederum können die Entstehung und Aufrechterhaltung von Übergewicht fördern. Tierstudien lieferten erste Hinweise, dass nicht nur Übergewicht an sich, sondern auch eine Ernährung reich an gesättigten Fetten und freien Zuckern – eine der wichtigsten Triebkräfte der aktuellen Adipositas-Pandemie – unabhängig von Übergewicht zu solchen maladaptiven Veränderungen in Dopamin-abhängigem Verhalten beitragen könnte. Belastbare Erkenntnisse aus Studien am Menschen stehen hierzu noch aus. Hier setzt diese Promotionsarbeit an, die den Einfluss einer diätetischen Dopamin-Vorläufer Manipulation – der akuten diätetischen Phenylalanin/ Tyrosin Depletion (APTD) – auf das Verstärkungslernen von zwei Gruppen gesunder Frauen untersucht, die sich in der habituellen Aufnahme von gesättigten Fettsäuren und freien Zuckern unterscheiden. Ausgehend von der Annahme, dass eine Ernährung reich an gesättigten Fetten und freien Zuckern zu veränderten dopaminergen Signalen führen könnte, erwartete ich, dass Dopamin-abhängiges Verstärkungslernen in den beiden Ernährungsgruppen unterschiedlich von der APTD beeinflusst werden würde. Dazu habe ich zunächst mithilfe des Dietary Fat and Free Sugar Kurzfragebogens (DFS) die habituelle Aufnahme von gesättigten Fettsäuren und freien Zuckern von gesunden Probandinnen erhoben. Auf Basis der erreichten Punktzahl im DFS wurden die Probandinnen entweder der Gruppe mit hoher oder der Gruppe mit niedriger Fett- und Zuckeraufnahme zugeteilt. Um einen möglichen Einfluss veränderter dopaminerger Signale zu bestimmen, habe ich dann eine diätetische Phenylalanin und Tyrosin Depletion durchgeführt. Diese Methode hat eine diätetische Manipulation der Dopamin-Synthese mittels Depletion von Dopamin-Vorläufern zum Ziel. Konkret wurde in früheren Studien bereits gezeigt, dass die APTD die peripheren Konzentrationen der Aminosäuren Phenylalanin und Tyrosin senkt, Dopaminvorstufen welche enzymatisch in Dopamin umgewandelt werden. Demzufolge senkt die APTD potenziell zentrales Dopamin in beiden Ernährungsgruppen. Verstärkungslernen habe ich schließlich mithilfe der Probabilistischen Auswahlaufgabe (PST), gemessen. Im Ergebnis konnte ich keine direkten Anhaltspunkte für einen Einfluss der Dopamin-Manipulation in Interaktion mit Ernährungsgruppen finden. Dennoch liefert diese Promotionsarbeit wichtige Ansatzpunkte für zukünftige Studien: In einer explorativen Analyse konnte ich vorläufige Hinweise für einen Zusammenhang zwischen Variationen in Dopamin-Vorstufen und einer habituellen fett- und zuckerreichen Ernährung aufzeigen. / Many studies have found alterations in dopaminergic signaling in different stages of obesity. Such alterations have been linked to maladaptive behaviors such as maladaptive alterations in the context of dopamine-dependent reinforcement learning. These behavioral changes are likely to foster the further emergence and maintenance of obesity. Animal studies have delivered first indications, that not only obesity itself, but also a diet high in saturated fat and free sugars – one of the main drivers of the current obesity epidemic – could independently contribute to such maladaptive alterations in dopamine-dependent behaviors. However, profound evidence in human studies is pending. Addressing this issue, this thesis investigates the influence of a dietary dopamine precursor manipulation – the acute phenylalanine/tyrosine depletion (APTD) – on reinforcement learning in two groups of healthy females that differ in their habitual intake of saturated fat and free sugars. Assuming, that a diet high in saturated fat and free sugars might lead to changes in dopaminergic signaling, I expected a differential influence of APTD on dopamine-dependent reinforcement learning in the diet groups. To test this hypothesis, I firstly assessed the habitual intake of saturated fat and free sugars in healthy female participants using the Dietary Fat and Free Sugar – Short Questionnaire (DFS). According to their score, participants were assigned either to the group with a high or the group with a low habitual intake of fat and sugar. To determine the impact of possible dopaminergic alterations, I secondly administered an acute phenylalanine/tyrosine depletion. This method aims at a dietary manipulation of dopamine synthesis via manipulation of its precursors. Concretely, the APTD has been shown to significantly reduce the peripheral concentration of the amino acids phenylalanine and tyrosine, dopamine precursors that are converted to dopamine enzymatically. Thus, the APTD is likely to lower central dopamine signaling in both diet groups. Thirdly, I measured reinforcement learning with the Probabilistic Selection Task (PST). As a result, I could not find direct evidence for an influence of APTD on reinforcement learning in interaction with diet groups. Nevertheless, this thesis supplies important starting points for further investigation: In an exploratory analysis, I could reveal preliminary evidence for a positive association between variations in dopamine precursors and habitual high-fat high-sugar diet.
98

Avaliação de indutores de resistência biótico, abiótico e extratos vegetais no controle de Meloidogyne incognita em tomateiro / Evaluation of resistance inductors biotic, abiotic and plant extracts for the control of Meloidogyne incognita on tomato plants

Formentini, Heloísa Maria 31 August 2012 (has links)
Made available in DSpace on 2017-07-10T17:40:42Z (GMT). No. of bitstreams: 1 Heloisa_Maria_Formentini_tese.pdf: 1264963 bytes, checksum: d416be804a86c6ba7273d6aacedf8878 (MD5) Previous issue date: 2012-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, the tomato is one of the vegetable species of great importance both economically and socially, however several factors are limiting its production as an example the diseases caused by nematodes of the genus Meloidogyne that limit the production in infested areas. Seeking new measures of protection and control of plant disease induced resistance is na alternative considerering that little attention has been directed to the possibility of induced resistance to root pathogens like nematodes. Therefore, this study aimed to verify the effectiveness of the chemical inducer acibenzolar-S-methyl, the biotic inductor Bacillus cereus and plant extracts of rosemary (Rosmarinus officinalis) and turmeric (Curcuma longa) in the induced resistance in susceptible and resistant tomato in plants infected with Meloidogyne incognita race 3. Two experiments were conducted simultaneously both followed the 2 x 6 factorial design with two tomato genotypes, one susceptible to M. incognita (Santa Clara) and a resistant (Ivety) and six treatments: ASM (125 mg i.a L -1 ), Bacillus cereus (6.10 7 CFU mL -1 ), rosemary 10%, turmeric 10%, water and a control (no inoculum and no spraying in the aerial part), with five replicates. Each vase with a capacity of 2 L, were filled with a mixture of soil, sand and compost previously autoclaved and homogenized in the ratio 2:2:1 and were transplanted to each one three tomato seedlings susceptible and resistant. The treatments were sprayed in the aerial part in tomato plants in all vases except the absolute control. At 72 h after the first application of treatments was carried out the inoculation of 407/100 cm 3 of J2 and eggs per vase. In the first experiment, using destructive samples of tomato treated and inoculated with M. incognita were determined the response of both genotypes to the treatments applied to the enzymatic activity of peroxidase, polyphenol oxidase, chitinase, β-1,3 glucanase and phenylalanine ammonia-lyase from roots of tomato plants that were macerated and homogenized to withdrawals in time 0 h, 24 h, 48 h, 96 h and 120 h after the first application of the treatments. In the second experiment, the variables analyzed to determine the effect of treatments on nematode population were the number of root-knots, juveniles and eggs in the soil accomplished at 56 days after the first application of the treatments that were reapplied every seven days during this period. From the results obtained it was concluded that there was a reduction in the number of root-knots in the roots of tomato plants showing no difference between the two genotypes for plants that received the treatments with acibenzolar-S-methyl, turmeric, rosemary and B. cereus. There was a reduction in the formation of root-knots in susceptible cultivar, confirming their potential in protecting the genotypes used against the attack of M. incognita. For the enzimatic activity peroxidase was the enzyme strongly associated with resistance with the highest activity in resistant genotype if compared to susceptible regardless of inducer treatment. In susceptible tomato B. cereus stood out in the induction of chitinase and peroxidase whereas for the resistant tomato rosemary induced peroxidase and polyphenol oxidase and rosemary extracts and turmeric induced chitinase enzyme to the susceptible genotype / No Brasil o tomate é uma das espécies de hortaliças de grande importância tanto no ponto de vista econômico quanto social, no entanto vários fatores são limitantes para sua produção como exemplo as doenças causadas por fitonematoides principalmente as espécies do gênero Meloidogyne que inviabilizam a produção nas áreas infestadas. Buscando novas medidas de proteção e controle de doenças de plantas a indução de resistência é uma alternativa haja vista que pouca atenção tem sido direcionada a possibilidade de indução de resistência à patógenos do sistema radicular como os fitonematoides. Assim este trabalho teve como objetivo verificar a eficácia do indutor químico acibenzolar-S-metil, do indutor biótico Bacillus cereus e de extratos vegetais de alecrim (Rosmarinus officinalis) e cúrcuma (Curcuma longa) na indução de resistência em tomateiros suscetível e resistente infectados com Meloidogyne incógnita raça 3. Foram conduzidos dois experimentos simultaneamente ambos seguiram o esquema fatorial 2 x 6 com dois genótipos de tomateiro um suscetível à M. incognita (Santa Clara) e um resistente (Ivety) e seis tratamentos: ASM (125 mg i.a L -1 ), Bacillus cereus (6.10 7 UFC mL -1 ), alecrim 10%, cúrcuma 10%, água e uma testemunha absoluta (sem inóculo e sem pulverização na parte aérea), com cinco repetições. Cada vaso, com capacidade para 2 L, foram preenchidos com a mistura de solo, areia e composto orgânico previamente autoclavados e homogeneizados na proporção 2:2:1 e para cada vaso foram transplantados três mudas de tomateiro suscetível e resistente. Os tratamentos foram pulverizados na parte aérea dos tomateiros em todos os vasos com exceção da testemunha absoluta. Às 72 h após a primeira aplicação dos tratamentos foi realizada a inoculação de 407/100 cm 3 de J2 e ovos por vaso. No primeiro experimento, utilizando amostras destrutivas de tomateiros tratados e inoculados com M. incognita foram determinadas a resposta dos dois genótipos aos tratamentos aplicados para a atividade enzimática das enzimas peroxidase, polifenoloxidase, quitinase, β-1,3 glucanase e fenilalanina amônia-liase a partir do macerado homogeneizado das raízes dos tomateiros para o tempo de coleta 0 h, 24 h, 48 h, 96 h e 120 h após a aplicação dos tratamentos. No segundo experimento, as variáveis analisadas para determinar o efeito dos tratamentos sobre a população do nematoide foram o número de galhas, juvenis e ovos presentes no solo realizado aos 56 dias após a primeira aplicação dos tratamentos que foram reaplicados a cada sete dias durante este período. A partir dos resultados obtidos concluiu-se que houve uma redução no número de galhas no sistema radicular dos tomateiros não apresentando diferença entre os dois genótipos para as plantas que receberam os tratamentos com acibenzolar-S-metil, cúrcuma, alecrim e Bacillus cereus. Houve uma redução na formação de galhas na cultivar suscetível, confirmando seu potencial na proteção dos genótipos utilizados contra o ataque do M. incognita. Para a atividade enzimática a peroxidase foi a enzima que esteve fortemente associada à resistência com a atividade superior no genótipo resistente em relação ao suscetível independentemente do tratamento indutor. No tomateiro suscetível o B. cereus destacou-se na indução de peroxidase e quitinase enquanto que para o tomateiro resistente o alecrim induziu peroxidase e polifenoloxidase e os extratos de alecrim e cúrcuma induziram a enzima quitinase para o genótipo suscetível
99

Orthogonality and Codon Preference of the Pyrrolysyl-tRNA Synthetase-tRNAPyl pair in Escherichia coli for the Genetic Code Expansion

Odoi, Keturah 2012 May 1900 (has links)
Systematic studies of basal nonsense suppression, orthogonality of tRNAPyl variants, and cross recognition between codons and tRNA anticodons are reported. E. coli displays detectable basal amber and opal suppression but shows a negligible ochre suppression. Although detectable, basal amber suppression is fully inhibited when a pyrrolysyl-tRNA synthetase (PylRS)-tRNAPyl_CUA pair is genetically encoded. trnaPyl_CUA is aminoacylated by an E. coli aminoacyl-tRNA synthetase at a low level, however, this misaminoacylation is fully inhibited when both PylRS and its substrate are present. Besides that it is fully orthogonal in E. coli and can be coupled with PylRS to genetically incorporate a NAA at an ochre codon, tRNAPyl_UUA is not able to recognize an UAG codon to induce amber suppression. This observation is in direct conflict with the wobble base pair hypothesis and enables using an evolved M. jannaschii tyrosyl-tRNA synthetase-tRNAPyl_UUA pair and the wild type or evolved PylRS-tRNAPyl_UUA pair to genetically incorporate two different NAAs at amber and ochre codons. tRNAPyl_UCA is charged by E. coli tryptophanyl-tRNA synthetase, thus not orthogonal in E. coli. Mutagenic studies of trnaPyl_UCA led to the discovery of its G73U form which shows a higher orthogonality. Mutating trnaPyl_CUA to trnaPyl_UCCU not only leads to the loss of the relative orthogonality of tRNAPyl in E. coli but also abolishes its aminoacylation by PylRS.

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