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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.
1

Úloha translačního iniciačního faktoru 3 v terminaci translace. / The role of translation initiation factor 3 (eIF3) in translation termination.

Beznosková, Petra January 2016 (has links)
Protein synthesis is a tightly regulated process of gene expression. Each gene has its start and its stop, which is determined by one of the three stop codons. Many recent articles describe ribosomes that purposely bypass stops on specific mRNAs to extend the nascent polypeptide to alter its properties. It is called programmed stop codon readthrough. Since over 15% of human genetic diseases are caused by so called premature termination codons (PTC) that halt translation and produce truncated proteins, this mechanism has a great potential implication in medical research. Numerous labs search for non-toxic drugs specifically increasing readthrough at PTCs; however, the success of this effort requires identification and understanding of all factors that are involved in this process. Here, we present one such factor eukaryotic initiation factor 3 (eIF3) and describe its ability to induce readthrough on stop codons in termination non-favorable context during programmed readthrough and also the consequences of its action on translation regulation. We additionally analyzed which near-cognate (nc) tRNAs are incorporated at UGA stop codons depending on the nucleotide that immediately follows them (so called +4 base). This way we established new rules for stop codon decoding and identified so called...
2

Mapování kontaktních míst mezi eukaryotickým translačním iniciačním faktorem eIF3 a 40S ribozomální podjednotkou. / Mapping the contact points between eukaryotic translation initiation factor eIF3 and the 40S ribosomal subunit.

Kouba, Tomáš January 2013 (has links)
Translation initiation in eukaryotes is a multistep process requiring the orchestrated interaction of several eukaryotic initiation factors (eIFs) together with the small ribosomal subunit to locate the mRNA's translational start and to properly decode the genetic message that it carries. The largest of these factors, eIF3, forms the scaffold for other initiation factors to promote their spatially coordinated placement on the ribosomal surface. It is our long-standing pursuit to map the 40S-binding site of the yeast multisubunit eIF3 and here we present three new mutual interactions between these two macromolecules (i) The C-terminal region of the eIF3c/NIP1 subunit is comprised of the conserved bipartite PCI domain and we show that a short C-terminal truncation and two clustered mutations directly disturbing the PCI domain produce lethal or slow growth phenotypes and significantly reduce amounts of 40S-bound eIF3 in vivo. The extreme C-terminus directly interacts with small subunit ribosomal protein RACK1/ASC1, which is a part of the 40S head, and, consistently, deletion of ASC1 impairs eIF3 association with ribosomes. The PCI domain per se shows strong but unspecific binding to RNA, for the first time implicating this protein fold in protein-RNA interactions. We conclude that the c/NIP1...
3

Úloha N-terminální domény a/TIF32 podjednotky iniciačního faktoru eIF3 ve vazbě mRNA na 43S pre-iniciační komplexy. / The role of the N-terminal domain of the a/TIF32 subunit of eIF3 in mRNA recruitment to the 43S pre-initiation complexes.

Vlčková, Vladislava January 2013 (has links)
Translation initiation is a complex process which results in the assembly of the elongation competent 80S ribosome from the 40S and 60S ribosomal subunits, the initiator tRNA and mRNA, and is orchestrated by numerous eukaryotic initiation factors (eIFs). Although it represents one of the most regulated processes of gene expression, the exact mechanism of one of the key steps of translation initiation - mRNA recruitment to the 43S pre-initiation complex (PIC) - is still only poorly understood. Recent studies indicated that besides eIF4F and poly(A)-binding protein, also eIF3 might play an important, if not crucial, role in this step. In our laboratory, we recently identified a 10 Ala substitution (Box37) in the a/TIF32 subunit of Saccharomyces cerevisiae eIF3, which interfered with translation initiation rates. Detailed analysis showed that this mutation significantly reduces the amounts of model mRNA in the gradient fractions containing 48S PICs as the only detectable effect in vivo. Moreover, a recently solved crystal structure of the N-terminal part of a/TIF32 pointed to two Box37 residues, Arg363 and Lys364, both proposed to contribute to one of the positive, potentially RNA-binding areas on the a/TIF32 surface. The fact that also their substitutions with alanines severely impaired the mRNA recruitment...
4

Les mécanismes d’initiation de la traduction de la polyprotéine Gag du Virus de l’Immunodéficience Humaine (VIH-1) / The translation initiation mechanisms of the Gag HIV-1 polyprotein

Ameur, Melissa 04 November 2016 (has links)
L'ARN génomique du Virus de l'Immunodéficience Humaine-1 (VIH-1) est multifonctionnel. Il constitue le génome encapsidé dans les virions et sert d'ARN messager pour la traduction des protéines virales Gag et Gag-Pol. La traduction de ces protéines dépend exclusivement de la machinerie traductionnelle cellulaire et est initiée par deux mécanismes différents : l'initiation canonique dépendante de la coiffe et l'initiation par entrée interne des ribosomes (IRES). Le VIH-1 présente deux IRES, l'un dans la région 5' non traduite (5'-UTR) qui est stimulé en phase G2/M du cycle cellulaire et l'autre dans la région codante de Gag. Ce dernier permet l'initiation de la traduction sur deux AUG en phase et conduit à la production de la protéine Gag pleine longueur mais également à la production d'une isoforme alternative de Gag, tronquée en région N-terminale. Le rôle de cette isoforme reste mal connu. Toutefois la mutation du second AUG chez VIH-1 et donc la suppression de la seconde isoforme de Gag provoque une diminution importante du taux de la réplication virale. La conservation structurelle et fonctionnelle de l'IRES Gag parmi les lentivirus suggère un rôle important de cette isoforme et de l'IRES gag dans le cycle viral. Nos travaux visent à comprendre à un niveau moléculaire les relations hôtes-pathogènes lors de la traduction des messagers viraux. Je me suis particulièrement intéressée aux rôles de la sous unité ribosomale 40S et de l'hélicase cellulaire DDX3 dans l'initiation de la traduction de la polyprotéine Gag du VIH-1. La première partie de ma thèse est consacrée à l'étude de l'interaction entre la sous unité ribosomale 40S et l'IRES gag du VIH-1. Par l'utilisation d'approches complémentaires, nous avons pu démontrer la présence de deux sites distincts de liaison au ribosome qui sont présents à proximité des deux codons d'initiation. Nous avons ensuite évalué à la fois in vitro et in cellulo (en collaboration avec l'équipe de T. Ohlmann, CIRI-ENS-Lyon) l'effet de la délétion de chacun des sites de liaison au 40S sur l'efficacité de traduction de la polyprotéine Gag. Nos résultats valident l'importance fonctionnelle des sites de liaison au ribosome pour une production optimale des deux isoformes de la polyprotéine Gag. La seconde partie de mon travail a consisté à définir le rôle de DDX3 dans l'initiation « coiffe-dépendante » de la traduction de la polyprotéine Gag. DDX3 est une hélicase à ARN à boîte DEAD impliquée dans de nombreux processus cellulaires tels que la régulation du cycle cellulaire et la réponse immunitaire innée mais également dans tous les aspects du métabolisme de l'ARN comme la transcription, l'épissage, l'export nucléaire ou encore la traduction. Plus récemment, il a été montré que DDX3 est nécessaire à la traduction de l'ARN génomique du VIH-1, cependant son rôle exact n'a pas encore été défini. Nous avons purifié une forme recombinante de la protéine en fusion avec la MBP (Maltose Binding Protein) et effectué des cinétiques enzymatiques afin de caractériser ses propriétés biochimiques. Contrairement à ce qui a été précédemment décrit, nos résultats montrent que DDX3 possède une activité ATPase strictement ARN-dépendante avec des constantes cinétiques similaires à celles de son homologue chez la levure, Ded1p. Nous avons également évalué l'activité hélicase de la protéine en présence de substrats de longueur et de nature variables (duplex ARN/ARN ou des hétéroduplex ADN/ARN). D'un point de vue fonctionnel, nous avons réalisé une première série d'expériences qui confirme la stimulation exercée par DDX3 sur la traduction de Gag in vitro. Ces résultats permettent d'envisager la caractérisation biochimique fine des interactions DDX3-ARN viral ainsi que de disséquer le rôle de DDX3 dans l'expression du génome viral. / The Human Immunodeficiency Virus (HIV) genomic RNA is multifunctional. It acts both as a genome that is packaged within virions and as messenger RNA translated to yield the Gag and Gag-Pol polyproteins. The translation of these proteins relies exclusively on the cellular translation machinery and is initiated through two mechanisms: the canonical cap-dependent initiation pathway and the use of internal ribosome entry sites (IRESes). HIV-1 has two IRESes, one located within the 5' UTR (5' UnTranslated Region) that is stimulated during the G2/M phase of the cell cycle, and the other embedded within the Gag polyprotein coding region. The later drives translation initiation from two AUG in frame and results in the production of the full-length Gag protein but also of an additional N-terminally truncated Gag isoform. Few things are known about this isoform, but the mutation of the second AUG causes a significant decrease in the rate of viral replication. The structural and functional conservation of Gag IRES among lentiviruses suggests an important role of this isoform and thus of the IRES in the viral cycle. Our work aims to understand at a molecular level the host-pathogen relationships in the translation of the viral messenger RNA. My work focused on the roles of the 40S ribosomal subunit and of the cellular helicase DDX3 in the translation initiation of Gag. During the first part of my Phd, I studied the interaction between the 40S ribosomal subunit and HIV-1Gag IRES. Following complementary approaches, we evidenced two distinct ribosome binding sites present close to the two the initiation sites of Gag. Then, we evaluated the effect of each 40S binding site deletion on Gag translation efficiency, both in vitro and in cellulo (in collaboration with the team of T. Ohlmann, CIRI-ENS-Lyon). Taken together, our results confirm the functional relevance of the two ribosomal binding sites to ensure optimal production of the two Gag isoforms. The second part of my Phd project aims to define the role of DDX3 in the translation initiation of Gag. DDX3 is a RNA DEAD-box helicase involved in many cellular processes such as cell cycle regulation and the innate immune response but also in all aspects of RNA metabolism such as transcription, splicing, mRNA nuclear export and translation. Recently DDX3 has been shown to favor HIV-1 Gag translation. To define its role, we first purified a recombinant form of the protein and performed kinetic experiments to analyze its biochemical properties. Contrary to what has been previously described, MBP-DDX3 displays a strictly RNA-dependent ATPase activity with kinetic constants similar to those displayed by its yeast counterpart Ded1p. We next evaluated MBP-DDX3 helicase activity towards RNA duplexes or RNA/DNA hybrids, with different length and single strand overhangs. Our preliminary results indicate that DDX3 alone is sufficient to enhance Gag translation in our in vitro system which paves the way to fine biochemistry experiments such as reconstruction of functional initiation complexes assembled onto Gag RNA and evaluation of its role on Gag RNA structure.
5

Civiliserade nordbor och primitiva främlingar : En kritisk diskursanalys av journal- och förfilm i folkhemmets Sverige / Civilized northerners and primitive strangers : A critical discourse analysis of newsreel and documentary short film in the Swedish welfare state

Österholm, Johan January 2006 (has links)
<p>This essay examines a small selection of Swedish newsreel and documentary short films, primarily travelogues, produced shortly before and after the second world war. The general aim is to expose differences in the representation of “The Other” and the “ethnic Swede” by applying a critical discourse analysis. The purpose is to illuminate how the material positions the latter as the norm and then contextualize this with xenophobic currents that had developed up until the middle of the twentieth century. Theoretical and methodological framework is drawn from the field of cultural studies as well as the nonfiction film. The analysis shows that the Swedish newsreel and travelogue indeed, to a high degree, possessed these currents even though part of them, mainly the anti-Semitic ideas, seems to relapse after the Holocaust.</p>
6

Civiliserade nordbor och primitiva främlingar : En kritisk diskursanalys av journal- och förfilm i folkhemmets Sverige / Civilized northerners and primitive strangers : A critical discourse analysis of newsreel and documentary short film in the Swedish welfare state

Österholm, Johan January 2006 (has links)
This essay examines a small selection of Swedish newsreel and documentary short films, primarily travelogues, produced shortly before and after the second world war. The general aim is to expose differences in the representation of “The Other” and the “ethnic Swede” by applying a critical discourse analysis. The purpose is to illuminate how the material positions the latter as the norm and then contextualize this with xenophobic currents that had developed up until the middle of the twentieth century. Theoretical and methodological framework is drawn from the field of cultural studies as well as the nonfiction film. The analysis shows that the Swedish newsreel and travelogue indeed, to a high degree, possessed these currents even though part of them, mainly the anti-Semitic ideas, seems to relapse after the Holocaust.
7

The role of Bud23 in the biogenesis of the small ribosomal subunit in Saccharomyces cerevisiae

White, Joshua Paul, 1977- 16 February 2011 (has links)
Ribosomes are the cellular structures responsible for the synthesis of protein in all branches of life. All ribosomes are made from a large and small subunit that in turn are composed of protein and RNA. The synthesis of eukaryotic ribosomes is a complex process involving more than 200 factors and spans three cellular compartments: the nucleolus, the nucloplasm, and the cytoplasm. The precise function of most of these ribosome biogenesis factors remains unknown. The RNA component of ribosomes is in part processed from a large RNA transcript that yields most of the RNA present in mature ribosomes. Part of the maturation process involves modification of this ribosomal RNA as processing is carried out. Recent work constructing protein interaction networks in Saccharomyces cerevisiae suggested the methyltransferase Bud23 was involved in ribosome biogenesis (1). This thesis describes my work to characterize Bud23 and place it within the ribosome biogenesis pathway. Bud23 is a SAM methyltransferase important for the proper biogenesis of the small ribosomal subunit. Here I will demonstrate that Bud23 methylates G1575 of the small subunit ribosomal RNA (SSU rRNA), and its absence delays export of the SSU rRNA from the nucleolas, and the nucleus, and results in the delayed maturation of the SSU rRNA. Finally, I will show that Bud23 function is connected to small subunit processome factor Utp14 through identification of a Utp14 mutant that suppresses the bud23[Delta] deletion phenotype. / text
8

Návrh parního generátoru pro modulární reaktor / Design of the steam generator for modular reactor

Černý, Marian January 2012 (has links)
Subject of this thesis is design of the steam generator for modular reactor. The dissertation consist of the theoretical part, where are described heat-exchangers and steam generators used in nuclear power plants. Second part contains theoretical calculations in the first approach (thermal, hydraulic and strenght calculation). In the next part are particular variants of steam generator selected. For the final variant are necessary calculations (introduced above) and drawings of selected parts are done. In the final statement is technical solution evaluated, and the parameters of the steam generator are compared with actually used steam generators.
9

Význam časopisu Vedem v terezínském ghettu / The Importance of the Journal Vedem in the Terezín Ghetto

ŠVECOVÁ, Lenka January 2010 (has links)
Vedem is a name of a Czech magazine, which was secretely published in the Terezín Ghetto in 1942{--} 1944. It´s existence is connected with Valter Eisinger, a ghetto teacher, who looked after Jewish boys in so-called block L417 and who was always supporting their cultural development and their creativity. Boys at of fourteen to sixteen undertook the publishing and the magazine was coming out every Friday for almost two years. The main themes were different columns, poems and novels but also philosophical essays or critical articles. The most important persons, Petr Ginz, who was a magazines general editor, or poetist Hanuš Hachenburg, bouth died in 1944 in gas chambers. After the World War II the magazine was taken to Praque in May 1945 but the new government in Czechoslovakia rejected its publishing. The first shortend version came out in 80´s under the name ``We are children just the same: Vedem, the secret magazine of the boys of Terezín.``
10

EL COMPOSITOR ESPAÑOL JOSÉ MARÍA RUIZ DE AZAGRA SANZ (1900-1971): BIOGRAFÍA Y OBRA

Traver Navarro, Paula 19 November 2015 (has links)
[EN] This doctoral thesis, that seeks to recover the figure and work of the Spanish composer José María Ruiz de Azagra Sanz (1900-1971), connects with the current lines of research about composers that developed their creative works mainly during the Spanish postwar period. Despite being one of the most prolific and popular composers of his time, in the lyric theatre (paso dobles, couplets, revue¿) genre as well as in the Spanish cinema from the 40s and 50s, Ruiz de Azagra has been ostracised and the references to his work or to his person are rarely existing, although some academic studies and specialized publications stand out, as those by Casares Rodicio, Llisterri or Roldán Garrote, that speak about some aspects of his life and work in the lyrical theatre and film music. The main aims of this work are the presentation and the setting-up of a thorough and updated biography of the composer, as well as his work cataloguing. After a broaden field work that involved the consultation of a wide range of sources, foundations and documentation centres, a biography and a catalogue of the author are presented along with a general analysis of the musical soundtrack for the film La torre de los siete jorobados as well as scores of some compositions for lyric theatre from the 50s, in order to stablish the author's own compositional features in both genres. Finally, it is also included the recovered piano and voice score of the song Manola lá through the playback of the audiovisual recording from the aforementioned film. / [ES] La presente tesis doctoral, que pretende recuperar la figura y obra del compositor español José María Ruiz de Azagra Sanz (1900-1971), entronca con la línea de investigación actual sobre compositores que desarrollaron su trabajo creativo principalmente durante la postguerra española. A pesar de tratarse de uno de los compositores más prolíficos y populares en su época tanto en el género del teatro lírico (pasodobles, cuplés, revista¿) como en el cine español de los 40 y 50, Ruiz de Azagra ha sido relegado al ostracismo y apenas existen referencias a su obra y su persona, si bien destacan algunos estudios académicos y publicaciones especializadas realizados por Casares Rodicio, Llisterri, o Roldán Garrote que hablan de algún aspecto de su vida y obra dentro del teatro lírico y la música cinematográfica. Los principales objetivos de este trabajo son la presentación y establecimiento de una biografía exhaustiva y actualizada del compositor así como la catalogación su obra. Tras un minucioso trabajo de campo que supuso la consulta en un amplio espectro de fuentes, fundaciones y centros documentales, se presenta junto con la biografía y el catálogo del autor, un análisis general de la banda sonora musical para la película La torre de los siete jorobados así como de algunas composiciones para teatro lírico de los años 50 con el fin de establecer unas características propias de composición del autor en ambos géneros. Por último, también se aporta la partitura recuperada para piano y voz de la canción Manola lá mediante la escucha del registro audiovisual perteneciente a la película anteriormente citada. / [CAT] La present tesi doctoral, que pretén recuperar la figura i l'obra del compositor espanyol José María Ruiz de Azagra Sanz (1900-1971), entronca amb la línia d'investigació actual sobre compositors que desenvoluparen el seu treball creatiu principalment durant la postguerra espanyola. Malgrat tractar-se d'un dels compositors més prolífics i populars en la seua època, tant en el gènere del teatre líric (pasdobles, cuplets, revista¿) com en el cinema espanyol dels anys 40 i 50, Ruiz de Azagra ha sigut relegat a l'ostracisme i quasi no existeixen referències a la seua obra i persona, si bé destaquen alguns estudis acadèmics i publicacions especialitzades realitzades per Casares Rodicio, Llisteri o Roldán Garrote que assenyalen algun aspecte de la seua vida i obra dins del teatre líric i de la música cinematogràfica. Els principals objectius d'aquest treball són la presentació i establiment d'una biografia exhaustiva i actualitzada del compositor així com la catalogació de la seua obra. Rere un minuciós treball de camp que va suposar la consulta en un ampli espectre de fonts, fundacions i centres documentals, es presenta junt amb la biografia i el catàleg de l'autor, una anàlisi general de la banda sonora musical per a la pel·lícula La torre de los siete jorobados, així com de algunes composicions per a teatre líric dels anys 50 amb la fi d'establir unes característiques pròpies de composició de l'autor en ambdós gèneres. Per últim, també s'aporta la partitura recuperada per a piano i veu de la cançó Manola lá mitjançant l'audició del registre audiovisual pertanyent a la pel·lícula anteriorment citada. / Traver Navarro, P. (2015). EL COMPOSITOR ESPAÑOL JOSÉ MARÍA RUIZ DE AZAGRA SANZ (1900-1971): BIOGRAFÍA Y OBRA [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/57709 / TESIS

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