Global ETD Search

11	Improving Expression Vectors for Recombinant Protein Production in Plants January 2012 (has links) abstract: Over the past decade, several high-value proteins have been produced using plant-based transient expression systems. However, these studies exposed some limitations that must be overcome to allow plant expression systems to reach their full potential. These limitations are the low level of recombinant protein accumulation achieved in some cases, and lack of efficient co-expression vectors for the production of multi-protein complexes. This study report that tobacco Extensin (Ext) gene 3' untranslated region (UTR) can be broadly used to enhance recombinant protein expression in plants. Extensin is the hydroxyproline-rich glycoprotein that constitutes the major protein component of cell walls. Using transient expression, it was found that the Ext 3' UTR increases recombinant protein expression up to 13.5- and 6-fold in non-replicating and replicating vector systems, respectively, compared to previously established terminators. Enhanced protein accumulation was correlated with increased mRNA levels associated with reduction in read-through transcription. Regions of Ext 3' UTR essential for maximum gene expression included a poly-purine sequence used as a major poly-adenylation site. Furthermore, modified bean yellow dwarf virus (BeYDV)-based vectors designed to allow co-expression of multiple recombinant genes were constructed and tested for their performance in driving transient expression in plants. Robust co-expression and assembly of heavy and light chains of the anti-Ebola virus monoclonal antibody 6D8, as well as E. coli heat-labile toxin (LT) were achieved with the modified vectors. The simultaneous co-expression of three fluoroproteins using the single replicon, triple cassette is demonstrated by confocal microscopy. In conclusion, this study provides an excellent tool for rapid, cost-effective, large-scale manufacturing of recombinant proteins for use in medicine and industry. / Dissertation/Thesis / Ph.D. Plant Biology 2012 Biology Molecular biology Plant biology bean yellow dwarf virus extensin plant protein expression terminator vector
12	Female Gender Representation in The Terminator Franchise Beis, Triantafyllos January 2021 (has links) The aim of this research is to investigate the representation of the female gender in theTerminator franchise and to examine whether there has been an evolution in thisrepresentation throughout the years. For this purpose, the representation of the lead femalecharacter, Sarah Connor, has been examined in the films The Terminator (Cameron, 1984),Terminator 2: Judgement Day (Cameron, 1991) and Terminator Genisys (Taylor, 2015), inwhich Sarah Connor is the only main female character. The thesis begins by providing athorough presentation of the situational, specific and the theoretical background of the threefilms analysed. Then, the methodology used in the research is described and linguistic, visualand contextual data are provided. These data are then analysed and discussed in relation tothe background of the films and to the objectives set at the beginning of the research. Inparticular, the linguistic aspect of gender representation is explored based on the waylanguage is used to represent women in the Terminator films. After a thorough analysis ofdata collected and discussed, the research concluded that there has, indeed, been an evolutionin female gender representation in the Terminator films, which reflects an evolution in theperception of gender by society itself. female gender representation linguistic analysis Terminator science-fiction. General Language Studies and Linguistics
13	Yeast Upf1 Associates With RibosomesTranslating mRNA Coding Sequences Upstream of Normal Termination Codons: A Dissertation Min, Ei Ei 15 April 2015 (has links) Nonsense-mediated mRNA decay (NMD) specifically targets mRNAs with premature translation termination codons for rapid degradation. NMD is a highly conserved translation-dependent mRNA decay pathway, and its core Upf factors are thought to be recruited to prematurely terminating mRNP complexes, possibly through the release factors that orchestrate translation termination. Upf1 is the central regulator of NMD and recent studies have challenged the notion that this protein is specifically targeted to aberrant, nonsense-containing mRNAs. Rather, it has been proposed that Upf1 binds to most mRNAs in a translation-independent manner. In this thesis, I investigated the nature of Upf1 association with its substrates in the yeast Saccharomyces cerevisiae. Using biochemical and genetic approaches, the basis for Upf1 interaction with ribosomes was evaluated to determine the specificity of Upf1 association with ribosomes, and the extent to which such binding is dependent on prior association of Upf1’s interacting partners. I discovered that Upf1 is specifically associated with Rps26 of the 40S ribosomal subunit, and that this association requires the N-terminal Upf1 CH domain. In addition, using selective ribosome profiling, I investigated when during translation Upf1 associates with ribosomes and showed that Upf1 binding was not limited to polyribosomes that were engaged in translating NMD substrate mRNAs. Rather, Upf1 associated with translating ribosomes on most mRNAs, binding preferentially as ribosomes approached the 3’ ends of open reading frames. Collectively, these studies provide new mechanistic insights into NMD and the dynamics of Upf1 during translation. Nonsense Codon Terminator Codon Nonsense Mediated mRNA Decay Trans-Activators Messenger RNA Ribosomes Saccharomyces cerevisiae Dissertations, UMMS Codon, Nonsense Codon, Terminator RNA, Messenger Genetics and Genomics
14	Inversion des spectres infrarouges enregistrés par l'instrument SOIR à bord de la sonde Venus Express / Inversion of the infrared spectra recorded by the SOIR instrument on board Venus Express Mahieux, Arnaud 03 March 2011 (has links) Vénus, deuxième planète du système solaire, souvent appelée sœur de la Terre, car présentant des caractéristiques de taille et de masse similaires, est fort différente de notre planète. En effet, son atmosphère est beaucoup plus dense et dynamiquement active que celle de la Terre. Dans ce travail, nous nous concentrerons sur la région s'étendant de 70 km à 180~km d'altitude :la mésosphère et la basse thermosphère.<p><p>SOIR, acronyme de Solar Occultation in the InfraRed, est un instrument russo-franco-belge embarqué à bord de la mission Venus Express de l'Agence Spatiale Européenne. Il utilise un réseau à échelle comme élément diffractant. La plage de nombre d'onde mesurable par SOIR s'étend de 2200 cm-1 à 4400 cm-1, ou 4.3 µm à 2.2 µm en longueur d'onde. Les ordres de diffraction utiles varient de 101 à 194. Un filtre acousto-optique - AOTF - est utilisé comme passe-bande pour sélectionner les ordres de diffraction. La résolution de l'instrument varie de 0.13 à 0.24 cm-1.<p><p>Du fait d'un temps de développement raccourci, presque toutes les calibrations de l'instrument ont dû être réalisées en vol. Elles comprennent les calibrations relatives au réseau à échelle (angle exact de Blaze et fonction de Blaze), au détecteur (non-uniformité pixel à pixel, courbe de sensibilité spectrale, relation entre les pixels et les nombres d'onde, résolution de l'instrument, intervalle d'échantillonnage spectral, rapport signal sur bruit, background thermique) et à l'AOTF (relation entre la radio-fréquence d'excitation de l'AOTF et les nombres d'onde, fonction de transfert de l'AOTF). L'approche et la réalisation de ces différentes calibrations sont présentées dans le présent travail. Les caractéristiques de l'instrument y sont également décrites.<p><p>Un algorithme d'inversion spectrale a été développé pour le cas spécifique de SOIR. Tenant compte du mode de mesure, l'occultation solaire, la méthode de la pelure d'oignons a été implémentée dans un algorithme dit de l'Estimation Optimale. Cette méthode permet d'inverser l'ensemble des mesures spectrales en une fois, et également d'en tirer d'autres informations, comme l'amélioration de certaines caractéristiques instrumentales. Les paramètres qui sont ajustés au sein de l'algorithme sont la densité de la ou des espèces absorbant dans la région spectrale concernée, la température, les paramètres de la ligne de base, qui permettent de déterminer les caractéristiques des aérosols, le déplacement Doppler des raies qui trouve principalement son origine dans la vitesse de déplacement du satellite, et l'amélioration de certaines calibrations. Une étude de sensibilité des différents paramètres de l'algorithme est également présentée, ainsi qu'une évaluation des erreurs instrumentales systématiques.<p><p>Dans l'ensemble des spectres enregistrés durant les 4 premières années de la mission, des profils verticaux de CO2, CO, H2O, HDO, SO2, H2SO4, HCl et HF ont été obtenus. Des valeurs limites de densité de OCS, H2CO, O3 et CH4 ont également été calculées. <p><p>Les résultats concernant le dioxyde de carbone sont développés dans le texte. Des profils verticaux de CO2 s'étendant de 70 km à 180 km d'altitude sont analysés en profondeur. Ils sont comparés aux profils dits hydrostatiques, et des hypothèses quant à la dynamique agissant au niveau des deux terminateurs de Vénus sont formulées.<p>/<p>Venus, second planet of the solar system, is often seen as the sister planet of the Earth. In terms of size and mass, they are indeed very similar, but the Venus atmosphere is much thicker and active. The altitude region extending from 70 km to 180~km is studied in this thesis, namely the mesosphere and the lower thermosphere.<p><p>SOIR, which stands for Solar Occultation in the InfraRed, is a Russian / French / Belgian instrument flying on board of the Venus Express (VEX) spacecraft of the European Space Agency. The diffracting device of SOIR is an echelle grating. The wavenumber region studied ranges from 2200 cm-1 to 4400 cm-1, or 4.3 µm to 2.2 µm in wavelength. The diffraction orders used with SOIR vary from 101 to 194. To select the required echelle grating diffraction order, an Acousto-Optical Tunable Filter - AOTF - is located after the entrance slit of the instrument. The instrument resolution varies from 0.13 to 0.24 cm-1.<p><p>SOIR was developed in a very short time. Thus, virtually all the calibrations had to be made in-flight. These concern the echelle grating (exact Blaze angle computation, Blaze function), the detector (pixel-to-pixel non-uniformity, spectral sensitivity curve, pixel-to-wavenumber relationship, instrument resolution, spectral sampling interval, signal-to-noise ratio, thermal background) and the AOTF (wavenumber to AOTF frequency relation, AOTF transfer function). The procedure for and the computation of these calibrations are described in this work, as well as the instrument characteristics.<p><p>A spectral inversion algorithm was developed specifically for the SOIR measurement technique: the solar occultation. The onion peeling method is implemented using the Optimal Estimation Method. It allows the inversion of the spectral data in one go, and also the enhancement of some instrumental characteristics. The algorithm variables are the densities of the species absorbing in the diffraction order, the temperature of the atmosphere under study, the spectral background parameters, that allow the determination of the Venus aerosols characteristics, the Doppler shift (mainly linked to the shift induced by the satellite displacement), and the improvement of some instrumental calibrations. A sensitivity study on the algorithm parameters is also presented, and the instrumental systematic errors are investigated.<p><p>Vertical profiles of CO2, CO, H2O, HDO, SO2, H2SO4, HCl and HF are derived from the spectra measured during the first 4 mission years. Upper limits on OCS, H2CO, O3 and CH4 have also been calculated. <p><p>We focus on the carbon dioxide results in the present study. A selection of vertical profiles extending from 70 km to 180 km are analyzed in details. They are compared to the hydrostatic profiles, and propositions concerning the terminators' dynamics are formulated.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished Mécanique Sciences de l'ingénieur Infrared spectra Spectre infrarouge Venus (Planet) -- Atmosphere Vénus (Planète) -- Atmosphère Spectroscopy Terminateur / Venus Calibration Vénus Spectroscopie Terminator
15	The coupling of transcription termination by RNA polymerase II to MRNA 3' end processing in Saccharomyces cerevisiae / Luo, Weifei. January 2006 (has links) Thesis (Ph.D. in Biochemistry) -- University of Colorado at Denver and Health Sciences Center, 2006. / Typescript. Includes bibliographical references (leaves 135-145). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;
16	Propagação guiada de ondas de VLF: aplicação ao estudo de fenômenos atmosféricos e naturais Cardenas, Jorge Enrique Samanes 17 February 2012 (has links) Made available in DSpace on 2016-03-15T19:37:41Z (GMT). No. of bitstreams: 1 Jorge Enrifque Samanes Cardenas.pdf: 3561395 bytes, checksum: ba28ce6fbd3bd0e1573255ccacb30d17 (MD5) Previous issue date: 2012-02-17 / Fundo Mackenzie de Pesquisa / Deep amplitude minima are observed in the daily records of Very Low Frequency (VLF, between 3 - 30 kHz) wave amplitudes. Amplitude minima are attributed to modal interference and modal conversion of waves propagating in the Earth - Ionosphere waveguide. The time of amplitude minima is related with the localization of the Terminator line and, therefore, is denominated of Terminator Time or TT time. In this work, we developed a methodology based on the monitoring of TT time to infer the distance of modal interference D and its temporal variation in relation to atmospheric and natural phenomena. For this purpose, we used data provided by the South America VLF Network (SAVNET) to the period 2007 - 2011. The results showed that the methodology is a promising tool to study the dynamics of the lower ionosphere, by means of the daily values of the undisturbed nighttime ionospheric height(hN). We identified short-term and long-term time variations of hN, where the long-term variation is possibly related with the solar activity cycle. We propose the use of this method to search for seismic- electromagnetic effects, and that it should be applied to medium and short propagation paths. Using the Long Wave Propagation Capability (LWPC) code, we simulated TT times and the results show good agreement with the observations, so a value for nighttime height hN = 88 km is suggested. This work will contribute to a greater viability of the use of the VLF technique for the study of the lower ionosphere and the forcings acting on this region of the atmosphere. / Pronunciados mínimos de amplitude são observados nos registros diários de sinais de muito baixa frequência ou VLF (do inglês Very Low Frequency, entre 3 - 30 kHz). A presença destes mínimos é atribuída a interferência e conversão modal de ondas se propagando no guia de onda Terra - Ionosfera. Os tempos de ocorrência destes mínimos são relacionados com a localização do Terminadouro e, por isso, são denominados de tempos de Terminadouro ou Tempos TT. Neste trabalho, desenvolvemos uma metodologia baseada no monitoramento dos tempos TT para inferir a distância de interferência modal D, e sua variabilidade temporal em relação a fenômenos atmosféricos e naturais. Para isso, utilizamos dados fornecidos pela rede SAVNET (South America VLF Network) durante o período 2007 - 2011. Os resultados mostraram que a metodologia é relevante para estudar a dinâmica da baixa ionosfera, através da obtenção de valores diários da altura noturna hN. Identificamos variabilidades de curto e longo período para hN, sendo estas últimas relacionadas ao ciclo de atividade solar. O método deverá ser aplicado à procura de efeitos sismo-eletromagnéticos utilizando caminhos com comprimento médios ou curtos. Foram realizadas simulações dos tempos TT, utilizando o código Long Wave Propagation Capability (LWPC), que mostraram boa concordância com as observações, sugerindo um valor de hN = 88 km para a altura noturna da baixa ionosfera. Os resultados apresentados neste trabalho contribuem para uma maior viabilização do uso da técnica de VLF, para o estudo da baixa ionosfera e os forçantes que agem sobre esta região da atmosfera terrestre. VLF (Very Low Frequency) terminadouro conversão modal efeitos sismo-eletromagnéticos VLF (Very Low Frequency) terminator line modal conversion seismic-electromagnetic effects
17	Stabil och antibiotikafri läkemedelsproduktion i rekombinant Escherichia coli Benevides, Kristina, Broström, Oscar, Elison Kalman, Grim, Swenson, Hugo, Vlassov, Andrei, Ågren, Josefin January 2017 (has links) Den här rapporten presenterar ett antibiotikafritt, stabilt och kromosombaserat expressionssystem för läkemedelsproduktion i Escherichia coli på beställning av företaget Affibody AB. E. coli-stammen BL21(DE3) valdes som värdorganism för expressionssystemet. Systemet består av en genkassett som innehåller en T7-promotor, en 5′-UTR från genen ompA och en terminatorsekvens från RNA-operonet rrnB. Fyra kopior av genkassetten ska integreras i pseudogenerna caiB, yjjM, hsdS och yjiV. En datormodell som modellerar det egentliga kopietalet i cellerna har skapats i mjukvaran MATLAB, vilket visar att det uppskattas vara maximalt 32 kopior av genkassetten per cell på grund av replikation av kromosomen. Ett högt pH i fermentorn; att använda fed-batch och blandade kolhydratkällor; och att använda stammen BL21(DE3) minskar acetatproduktionen i cellen. En lägre acetatproduktion kan leda till en högre produkthalt. En proteinutbytesmodell för mjukvaran MATLAB har konstruerats för att uppskatta koncentrationen av Affibody®-molekylen i en E. coli cell. copynumber copy-number copy number origin of replication rekombinant proteinexpression läkemedel E. coli antibiotikafri antibiotika expressionssystem expression system escherichia coli kromosom kromosombaserad kromosomal plasmidfri plasmid T7-promotor T7 promotor ompA rrnB autoinduktion auto induktion matlab kopietalmodell utbytemodell stabil pH pseudogen pseudo gen caiB yjjM hsdS yjiV fermentor batch fed-batch kontinuerlig fed batch fermentation Affibody affibody-molekyl affibody-molekyler affibodymolekyl affibodymolekyler bioreaktor acetat acetatbildning acetatproduktion acetatreduktion acetatreducering peptidläkemedel peptider peptid T7-system operator lac-operator operon 5'-UTR 3'-UTR sekundärstruktur mRNA T1 T2 terminator termineringssekvens optimering lac-operon repressor inducering BL21(DE3) BL21 B-stam B stam modell kopietal kopie tal OriC Pharmaceutical Biotechnology Läkemedelsbioteknik

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