En el ámbito laboral, hemos constatado personalmente que en el planteamiento de personajes se produce una influencia proveniente de los lineamientos específicos de una campaña. Aun cuando el diseñador tiene un estilo propio, entra a calar la opinión del cliente o las exigencias del mercado. Por ello, nos preguntamos qué sucedería si el diseñador decidiera plantear una propuesta personal distinta en función del diseño de personajes. Obtuvimos respuesta a tal cuestionamiento en la Internet, donde se hallaron varios proyectos fuera del ámbito comercial, con una diversidad de estilos en campos como el arte, el diseño y la animación. Este hecho sembraría nuestro interés inicial en el que se denominaría contemporary character design e iniciaría nuestra exploración en diversos medios artísticos más allá del software de diseño digital. El resultado sería la creación de una serie de personajes que conformarían parte de un imaginario y estarían construidos con un lenguaje visual propio. El contemporary character design, término que en español significa “diseño de personajes contemporáneo”, convive con otras maneras de construir personajes como los que podemos apreciar en la animación en general, el cómic y el diseño de mascotas publicitarias. Sobrepasando tales parámetros comerciales, el contemporary character design ha llegado a desarrollarse y expandirse artísticamente demostrando su potencial creativo y manifestando rasgos característicos que lo diferencian de las otras expresiones artísticas mencionadas. Es importante aclarar que los proyectos vinculados al contemporary character design, si bien parten del entorno del diseño, nacen de proyectos libres en donde un diseñador o artista gráfico parodia o explora de manera lúdica los comportamientos y percepciones de la sociedad moderna en diversos ámbitos. Para ello, uno de los recursos más utilizados es el intertexto que toma como referencia la globalización de la imagen. No obstante, esta superposición de información podría tomar nuevas fuentes que no sólo se basen en el mass media y cuyo propósito sea más introspectivo, lo que abre las posibilidades de elaborar una propuesta artística en un nivel plástico y conceptual. / Tesis

DGCR8 (DiGeorge critical region 8) protein constitutes part of the Microprocessor complex together with Drosha, and is involved in the nuclear phase of microRNA (miRNA) biogenesis. DGCR8 recognises the hairpin RNA substrates of precursor miRNAs through two double-stranded RNA (dsRNA) binding motifs and acts as a molecular anchor to direct Drosha cleavage at the base of the pri-miRNA hairpin. Recent characterisation of the RNA targets of the Microprocessor by HITSCLIP of DGCR8 protein revealed that this complex also binds and regulates the stability of several types of transcripts, including mRNAs, lncRNAs and retrotransposons. Of particular interest is the binding of DGCR8 to mature small nucleolar RNA (snoRNA) transcripts, since the stability of these transcripts is dependent on DGCR8, but independent of Drosha. This raises the interesting possibility that there could be alternative DGCR8 complex/es using different nucleases to process a variety of cellular RNAs. We performed mass spectrometry experiments and revealed that DGCR8 copurifies with subunits of the nucleolar exosome, which contains the exonuclease RRP6. We demonstrated DGCR8 and the exosome form a nucleolar complex, which degrade the mature snoRNAs tested within this study. Interestingly, we also show that DGCR8/exosome complex controls the stability of the human telomerase RNA component (hTR/TERC), and absence of DGCR8 creates a concomitant telomere phenotype. In order to identify the RNA targets of the DGCR8/Exosome complex on a global scale we performed iCLIP of endogenous and overexpressed RRP6 (wild-type and a catalytically inactive form). Thus, intersection of CLIP datasets from DGCR8 and RRP6 identified common substrates; accordingly snoRNAs were the most represented. In addition, we identified the cellular RNA targets of the RRP6 associated human exosome. The use of a catalytically inactive form of RRP6 stabilised important in vivo interactions that are highly dynamic and transient and also highlighted the role of RRP6-mediated trimming of 3’flanks of immature non-coding RNAs. We will present a global view of the RNA-binding capacity of the RRP6-associated exosome. In sum, we identified a novel function for DGCR8, acting as an adaptor to recruit the exosome to structured RNAs and induce their degradation. Moreover, we have identified DGCR8-depenedent substrates of the exosome and have demonstrated the requirement of RRP6 for 3’ processing of ncRNAs.

In this study, the capacitance displacement system (CDS) is employed to measure the post-weld-shift (PWS) induced by laser welding in butterfly type laser module package. The advantage of CDS is able to simultaneously and immediately measure the direction and the magnitude of PWS. Furthermore, with the aid of notch clip, the PWS can efficiently and quantitatively be compensated by laser hammering technique to regain the coupling power. Reduction of the PWS is an important issue in developing low-cost and high-performance laser modules. The package yield of laser modules can be imp roved due to the real-time measurement and quantitative compensation. In comparison with the high-magnification camera with image capturing system (HMCICS) having 0.7£gm resolution, the capacitance sensor achieves 25.4nm and 0.1£gm in its resolution and accuracy, respectively. Besides, during the package procedure, the real-time displacement detection can be used to adjust the package parameters. As a result, the PWS is reduced that contributes to less coupling power loss. After welding, the result reveals that the PWS was measured as X=0.15£gm and Y=-4.58£gm, while the coupling power is 43.19%.

Zugl.: Braunschweig, Techn. Univ., Diss., 2008

ROMO, Adolfo Ignacio Barros. Complexos de cobre com o ligante 2cp-bz-sme, um derivado sulfurado da base clip-phen. Síntese, caracterização e estudos de geração de radicais e clivagem de DNA. 2015. 86 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Celia Sena (celiasena@dqoi.ufc.br) on 2017-07-20T17:39:05Z No. of bitstreams: 1 2015_dis_aibromo.pdf: 2488610 bytes, checksum: 2569053eabcca5c69c4678ab7eccc69e (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-08-29T20:42:39Z (GMT) No. of bitstreams: 1 2015_dis_aibromo.pdf: 2488610 bytes, checksum: 2569053eabcca5c69c4678ab7eccc69e (MD5) / Made available in DSpace on 2017-08-29T20:42:39Z (GMT). No. of bitstreams: 1 2015_dis_aibromo.pdf: 2488610 bytes, checksum: 2569053eabcca5c69c4678ab7eccc69e (MD5) Previous issue date: 2015 / Coordination compounds of copper have been invoked as major actors in processes involving the reduction of molecular oxygen, mostly with the generation of radical species whose assignment have so far not been unanimously addressed. In the present work we have joined results acquired on surface and solution to get insights on the radical oxygen species (ROS) generated by a copper(II) coordination compound containing a thioether clip-phen derivative, 1,3-bis(1,10-phenanthrolin-2-yloxy)-N-(4-(methylthio) benzyli-dene)propan-2-amine (2CP-Bz-SMe). The adsorption of the copper(II) complex on gold surface was spontaneously by simple immersion of the metallic substrate in aqueous solution of the complex. The characterization of the modified gold electrode, which was performed by electrochemistry and surface Raman spectroscopy (SERS – Surface Enhanced Raman Scattering), indicated that the adsorption occurs through the sulfur atom of the thioether fragment of the molecule. While surface plasmon resonance (SPR) and electrochemistry of the adsorbed complex indicated the formation of a dimeric Cu(I) intermediate containing molecular oxygen as bridging ligand, scanning electrochemical microscopy images (SECM) pointed for OH• radical generation. Spin trapping measurements acquired by electron paramagnetic resonance (EPR) and nuclease assays run in the presence of radical scavengers, reinforced such conclusions showing that the radical production is dependent on the amount of oxygen and H2O2. Therefore, it is reasonable to assume a catalytic mechanism involving Fenton-like reaction in which the copper(II) complex is, at first, reduced to copper(I). Accordingly, in the presence of oxygen and in acid medium, the reduced compound is oxidized by H2O2 resulting in the recovering of the parent complex and in the generation of OH• that, in turn, must be the ROS responsible for the DNA cleavage. The results obtained during the developing of this proposal were presented at the XVII Brazilian Meeting on Inorganic Chemistry and are in the final compilation stage for publication in peer-reviewed journal / Compostos de coordenação de cobre têm sido considerados peças fundamentais em processos que envolvem a redução de oxigênio molecular, particularmente com a geração de espécies radicalares cujas atribuições, até a atualidade, não são unanimidade. Neste trabalho, foram reunidos resultados obtidos em superfície e em solução a fim de obter informações sobre a espécie reativa de oxigênio (ROS – Reactive Oxygen Species) gerada por um composto de coordenação de cobre(II) contendo um derivado tioéter do ligante clip-phen, 1,3-bis(1,10-fenantrolin-2-iloxi)-N-(4-(metiltio)benzilideno)propan-2-amina (2CP-Bz-SMe). A adsorção do complexo de cobre(II) sobre superfície de ouro foi realizada de forma espontânea por simples imersão do substrato metálico em solução aquosa do complexo. A caracterização do eletrodo de ouro modificado foi feita por eletroquímica e espectroscopia Raman de superfície (SERS – Surface Enhanced Raman Scattering) onde se concluiu que a adsorção ocorre através do átomo de enxofre do fragmento tioéter da molécula. Enquanto os resultados de ressonância de plásmons de superfície (SPR – Surface Plasmon Resonance) e eletroquímica sugeriram a formação de um intermediário dimérico de Cu(I) contendo oxigênio molecular como ligante ponte, imagens de microscopia de varredura eletroquímica (SECM – Scanning Electrochemical Microscopy) indicaram a geração do radical hidroxil, OH•. Os experimentos de captura de spin por ressonância paramagnética de elétrons (EPR – Electron Paramagnetic Resonance) e ensaios de nuclease de DNA, os quais envolveram a utilização de inibidores de ROS, mostram que a geração do radical depende da quantidade de oxigênio e H2O2. Assim, é razoável admitir um mecanismo catalítico envolvendo reações do tipo Fenton onde o complexo de cobre(II) é, inicialmente, reduzido a cobre(I). Na presença de oxigênio e em meio ácido, o composto reduzido é oxidado por H2O2 resultando na regeneração do complexo de partida e na formação do radical OH• que, por sua vez, deve ser a espécie ROS responsável pela clivagem do DNA. Os resultados deste projeto foram apresentados no XVII Brazilian Meeting on Inorganic Chemistry e estão em fase final de compilação para publicação em periódico indexado

Gene expression in eukaryotic cells is regulated by the combinatorial action of numerous gene-regulatory factors, among which microRNAs (miRNAs) play a fundamental role at the post-transcriptional level. miRNAs are single-stranded, small non-coding RNA molecules that emerge in a cascade-like fashion via the generation of primary and precursor miRNAs. Mature miRNAs become functional when incorporated into the RNA induced silencing complex (RISC). miRNAs guide RISCs to target mRNAs in a sequence-specific fashion. To this end, base-pairs are usually formed between the miRNA seed region, spanning nucleotide positions 2 to 8 (from the 5' end) and the 3'UTR of the target mRNA. Once miRNA-mRNA interaction is established, RISC represses translation and occasionally induces direct or indirect target mRNA degradation. Interestingly, miRNAs are expressed not only in every multicellular organism but are also encoded by several viruses, predominately by herpesviruses. By controlling both, cellular as well as viral mRNA transcripts, virus-encoded miRNAs confer many beneficial effects on viral growth and persistence. Murine cytomegalovirus (MCMV) is a ß-herpesvirus and so far, 29 mature MCMV-encoded miRNAs have been identified during lytic infection. Computational analysis of previously conducted photoactivated ribonucleotide-enhanced individual nucleotide resolution crosslinking immunoprecipitation (PAR-iCLIP) experiments identified a read cluster within the 3' untranslated region (3'UTR) of the immediate early 3 (IE3) transcript in MCMV. Based on miRNA target predictions, two highly abundant MCMV miRNAs, namely miR-m01-2-3p and miR-M23-2-3p were found to potentially bind to two closely positioned target sites within the IE3 PAR-iCLIP peak. To confirm this hypothesis, we performed luciferase assays and showed that activity values of a luciferase fused with the 3'UTR of IE3 were downregulated in the presence of miR-m01- 2 and miR-M23-2. In a second step, we investigated the effect of pre-expression of miR-m01-2 and miR-M23-2 on the induction of virus replication. After optimizing the transfection procedure by comparing different reagents and conditions, plaque formation was monitored. We could demonstrate that the replication cycle of the wild-type but not of our MCMV mutant that harbored point mutations in both miRNA binding sites within the IE3-3'UTR, was significantly delayed in the presence of miR-m01-2 and miR-M23-2. This confirmed that miR-m01-2 and miR-M23-2 functionally target the major transcription factor IE3 which acts as an indispensable regulator of viral gene expression during MCMV lytic infection. Repression of the major immediate early genes by viral miRNAs is a conserved feature of cytomegaloviruses. The functional role of this type of regulation can now be studied in the MCMV mouse model. / In eukaryotischen Zellen wird die Expression von Genen durch das Zusammenspiel vieler verschiedener biologischer Regulatoren, wie microRNAs (miRNAs), kontrolliert. MiRNAs sind einzelsträngige, kurze, nicht-kodierende RNA-Moleküle, die aus sogenannten primären miRNAs und Vorläufer-miRNAs entstehen und die Genexpression auf Ebene der Posttranskription beeinflussen. Um ihre Funktion ausüben zu können, werden reife miRNAs in RNA-induzierte Silencing-Komplexe (RISCs) eingebaut und zu ihren Ziel-mRNAs geführt. Durch Wechselwirkungen zwischen der miRNA "seed-Region , die die Nukleotide 2 bis 8 vom 5'-Ende überspannt und der 3'UTR (3' untranslatierte Region) der Ziel-mRNA, unterdrückt RISC die Translation der Ziel-mRNA und kann deren Abbau durch direkte sowie indirekte Mechanismen induzieren. Die Expression von miRNAs wurde nicht nur in multizellulären Organismen, sondern in bereits zahlreichen Viren, insbesondere in der Virusfamilie der Herpesviridae, nachgew- iesen. Viruskodierte miRNAs kontrollieren dabei zelluläre wie auch virale mRNA-Transkripte und verleihen dem Virus einen Selektionsvorteil bzgl. Wachstum und Persistenz. Das mur- ine Cytomegalievirus (MCMV) ist ein β-Herpesvirus, das nach aktuellem Wissensstand 29 reife miRNAs kodiert, die allesamt während der lytischen Infektion identifziert wurden. Bioinformatische Analysen eines vor dieser Arbeit durchgeführten PAR-iCLIP-Experiments (photoactivated ribonucleotide-enhanced individual nucleotide resolution crosslinking and immunoprecipitation), zeigten einen PAR-iCLIP Peak in der 3'UTR (3' untranslatierte Region) des immediate early 3-Transkripts (IE3) von MCMV. Unter Verwendung von RNAhbybrid, einem miRNA target prediction tool, fanden sich zwei virale miRNAs, näm- lich miR-m01-2-3p und miR-M23-2-3p mit potentiellen Bindestellen innerhalb der 3'UTR des MCMV IE3 Transkripts. Unsere konsekutiv durchgeführten Luciferase-Assays be- stätigten, dass sowohl miR-m01-2 als auch miR-M23-2 an die 3'UTR von IE3 binden. Beide viralen miRNAs führten zu einer verminderten Luciferaseaktivität unter Verwendung von Reportern, in denen die 3'UTR des IE3-Gens mit dem Luciferase-Transkript fusioniert war. xxiv Summary Das IE3 Protein gilt während des lytischen Zykluses als einer der wichtigsten Transkrip- tionsfaktoren von MCMV. Ebenfalls wurde der Einfluss der beiden viralen miRNAs auf die virale Reproduktion von uns untersucht. Hierfür wurden murine Zelllinien vor Infektion mit miR-m01-2 und miR- M23-2 transziert. Das Transfektionsverfahren optimierten wir zunächst durch Testung verschiedener Reagenzien und experimenteller Bedingungen. Schließlich zeigten wir mittels Plaqueassays, dass eine vor Infektion durchgeführte Transfektion mit miR-m01-2 und miR- M23-2 die Replikation von MCMV signifikant verzögerte. Unter Verwendung einer MCMV- Mutante, die durch Punktmutationen in beiden miRNA-Bindungsstellen innerhalb der IE3- 3'UTR charakterisiert war, ließ sich dieser Effekt aufheben. Unsere Experimente weisen somit stark darauf hin, dass miR-m01-2 und miR-M23-2 die Expression des IE3 Proteins regulieren und damit indirekt Einfluss auf die Genexpression während der lytischen Phase des Replikationszykluses von MCMV nehmen. Die miRNA-mediierte Repression der immediate early Genexpression stellt ein evolutionär konserviertes Merkmal von Zytomegalieviren dar. Für eine weitere Einordnung der Rolle dieser Genexpressionskontrolle bedarf es zukünftige Untersuchungen im MCMV-Tiermodell

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Online video platforms receive hundreds of hours of uploads every minute, making manual moderation of inappropriate content impossible. The most vulnerable consumers of malicious video content are children from ages 1-5 whose attention is easily captured by bursts of color and sound. Prominent video hosting platforms like YouTube have taken measures to mitigate malicious content, but these videos often go undetected by current automated content moderation tools that are focused on removing explicit or copyrighted content. Scammers attempting to monetize their content may craft malicious children's videos that are superficially similar to educational videos, but include scary and disgusting characters, violent motions, loud music, and disturbing noises. A robust classification of malicious videos requires audio representations in addition to video features. However, recent content moderation approaches rarely employ multimodal architectures that explicitly consider non-speech audio cues. Additionally, there is a dearth of comprehensive datasets for content moderation tasks which include these audio-visual feature annotations. This dissertation addresses these challenges and makes several contributions to the problem of content moderation for children’s videos. The first contribution is identifying a set of malicious features that are harmful to preschool children but remain unaddressed and publishing a labeled dataset (Malicious or Benign) of cartoon video clips that include these features. We provide a user-friendly web-based video annotation tool which can easily be customized and used for video classification tasks with any number of ground truth classes. The second contribution is adapting state-of-the-art Vision-Language models to apply content moderation techniques on the MOB benchmark. We perform prompt engineering and an in-depth analysis of how context-specific language prompts affect the content moderation performance of different CLIP (Contrastive Language-Image Pre-training) variants. This dissertation introduces new benchmark natural language prompt templates for cartoon videos that can be used with Vision-Language models. Finally, we introduce a multimodal framework that includes the audio modality for more robust content moderation of children's cartoon videos and extend our dataset to include audio labels. We present ablations to demonstrate the enhanced performance of adding audio. The audio modality and prompt learning are incorporated while keeping the backbone modules of each modality frozen. Experiments were conducted on a multimodal version of the MOB (Malicious or Benign) dataset in both supervised and few-shot settings.

Neste trabalho são caracterizados corpos sub-vulcânicos expostos no nordeste da Cordilheira Ocidental da Colômbia através de estudos petrográficos, análises geoquímicas em rocha-total e datação U-Pb por SHRIMP IIe em zircão. A área de estudo, em um contexto regional, representa um orógeno de acreção no sistema andino, constituído por rochas ígneas de afinidade oceânica amalgamadas contra a margem ocidental de América do Sul e associadas ao desenvolvimento da Grande Província Ígnea do Caribe (Caribbean Large igneous Province-CLIP). As análises em geoquímica elementar evidenciam para os corpos subvulcânicos um ambiente de subducção intra-oceânico de arco primitivo a mais evoluído, com significante contribuição de sedimentos subductados e assinaturas similares às registradas para as rochas vulcânicas e plutônicas presentes na área (Formação Barroso e Tonalito de Santa Fe e Buriticá). Dados isotópicos de Sr e Nd (razão inicial 87Sr/86Sr entre 0.70334 a 0.70543 e ?Nd entre +6.25 a +7.42) indicam uma área fonte de cunha mantélica, típica de rochas de arco, com níveis subordinados de material crustal. Idades U-Pb por SHRIMP IIe em zircão mostram cinco populações de idades correspondentes a: idades Neoarquenas ao redor de 2700 Ma, Paleoproterozoicas em torno de 2100, 2000 e 1800 Ma, Neoproterozoicas ao redor de 600 Ma, Ordovicianas/Devonianas de 460 e 360 Ma, e Cretáceas ao redor de 90 Ma. A população de idades mais novas é interpretada como a idade de cristalização dos corpos estudados, indicando uma relação espacial e temporal com as rochas ígneas da área associadas ao desenvolvimento da CLIP. As quatro populações de idades mais antigas são atribuídas a xenocristais, interpretados como provenientes de sedimentos terrígenos que foram arrastados ao canal de subducção, refletindo processos de reciclagem crustal através do manto em zonas de subducção intra-oceânicas. Foram identificadas duas possíveis áreas fontes para os xenocristais de zircão: o Complexo Marañon e o Maciço de Arequipa, que constituem inliers expostos na margem ocidental de América do Sul e apresentam uma boa correlação entre os eventos magmáticos/metamórficos que registram e às idades dos xenocristais encontrados. A partir destas interpretações, foi restringido o local de formação dos corpos estudados em relação à paleomargem continental, considerando além dados paleomagnéticos e modelos paleogeográficos publicados na zona de estudo. O trabalho fornece um aporte significativo para a compreensão da evolução tectono-magmática da região durante o Cretáceo superior, associada à história geológica da CLIP. / In this study sub-volcanic bodies exposed in the northeast of the Western Cordillera of Colombia are characterized through petrographic descriptions, geochemical analysis in bulk rocks and geochronology U-Pb SHRIMP in zircon. The area, in a regional context, represents an accretion orogen in the Andean system, it is composed of igneous rocks of oceanic affinity accreted to the western margin of South America, and they are associated to the development of the Caribbean Large igneous Province (CLIP). Based on geochemical characterization, the sub-volcanic bodies display patterns of an intra-oceanic subduction environment of primitive to evolved island arc, with significant contribution of subducted sediments, and similar signatures to those reported for the volcanic and plutonic rocks present in the area. (Barroso Formation and Santa Fe and Buriticá Tonalite). The Sr and Nd isotopic data (initial ratios 87Sr/86Sr between 0.70334 a 0.70543 and ?Nd between +6.25 a +7.42) suggest a wed mantle source, typical of arc rocks, with subordinates levels of crustal material. SHRIMP U-Pb data show five age populations that include: Neoarchean age around 2700 Ma, Paleoproterozoic age about of 2100, 2000 and 1800 Ma, Neoproterozoic age of 600 Ma, Ordovician-Devonian age of 460 and 360 Ma, and Cretaceous age around 90 Ma. The younger age population is interpreted as the crystallization age of the studied bodies; it indicated a special and temporal relation with the igneous rocks of the area which are associated with the development of the CLIP. The other four age populations are attributed to xenocrystals, they are interpreted as coming from terrigenous sediments dragged for the subduction area, reflecting process of crustal recycling through the mantle in intra-oceanic subduction zones. We restricted two possible source areas for the xenocrystals zircon: The Marañon Complex and The Arequipa Massif. They are constitute inliers exposed of the western margin of South America and present a good correlation between the magmatic/metamorphic events and the ages of the finding in our xenocristals. Based on these interpretations, we constraint the local of formation of the studied bodies closer to the continental paleomargin, considering also paleomagnetic data and paleogeographic models published in the area. The present study provides a significant contribution for the understanding tectono-magmatic evolution of the region during of Cretaceous, associated with the geological history of the CLIP.

Terminaison de la transcription. Rho se fixe aux transcrits naissants au niveau d’un site Rut (Rhoutilization) libre à partir duquel il transloque le long de l’ARN (5’→3’) de façon ATP-dépendante pour rattraper le complexe d’élongation de la transcription et induire la dissociation de celui-ci. Il est généralement admis que les sites de fixation de Rho présentent une richesse en Cytosines et une pauvreté en Guanines, ainsi qu’une relative pauvreté en structures secondaires. Les études génomiques ou transcriptomiques n’ont pas dégagé d’éléments consensus ou de règles permettant de prédire les sites de terminaison Rho-dépendants. En combinant approches biochimiques et bioinformatiques, j’ai tenté de comprendre les mécanismes par lesquels Rho reconnait les transcrits.J’ai identifié un ensemble de déterminants de séquence qui, pris ensemble, possèdent un bon pouvoir prédictif et que j’ai utilisé pour construire le premier modèle computationnel capable de prédire la terminaison Rho-dépendante à l’échelle des génomes d’E. coli et Salmonella. J’ai caractérisé in vitro certains de ces terminateurs, en particulier dans les régions 5’UTR, avec l’espoir qu’ils soient impliqués dans des mécanismes de régulation conditionnelle. J’ai identifié des candidats dont l’activité pourrait être sous le contrôle de facteurs comme des petits ARN non codants (sRNA) ou latempérature. J’ai également développé une méthode fluorogénique pour détecter facilement la terminaison Rho-dépendante in vitro et ai commencé à adapter l’approche CLIP-seq à l’étude du transcriptome Rho-dépendant chez Salmonella. Collectivement, mes travaux offrent de nouveaux outils d’analyse et de prédiction de la terminaison Rho-dépendante, une meilleure cartographie des sites d’action de Rho chez E. coli et Salmonella, ainsi que de nouvelles pistes d’étude du rôle de Rhodans l’expression conditionnelle du génome. / Transcripts at a free Rut (Rho-utilization) site from which Rho moves along the RNA in an ATP dependentfashion to catch up with and dissociate the transcription elongation complex. It is generally believed that the Rut sites are, respectively, rich and poor in Cytosines and Guanines as well as relatively poor in secondary structures. Studies at the genomic or transcriptomic scale have notrevealed any stronger consensus features or rules for predicting potential Rho-dependent termination sites. By combining biochemical and bioinformatics approaches, I have explored the mechanisms by which Rho recognizes transcripts to induce transcription termination. I have identified a complex set of sequence determinants which, taken together, have good predictive power and which I used to build the first computational model able to predict Rho-dependent termination at the scale of Escherichiacoli and Salmonella genomes. I have characterized in vitro some of these terminators, particularly in 5'UTRs, with the hope that they will be involved in conditional regulatory mechanisms. I have identified several candidates whose activity may be under the control of factors such as small non-coding RNAs(sRNA) or temperature. I have also developed a fluorogenic method to easily detect Rho-dependent termination in vitro and have begun to adapt the CLIP-seq approach to the study of the Rhodependent transcriptome in Salmonella. Collectively, my work offers new tools for the analysis and prediction of Rho-dependent termination, a better mapping of the sites of probable Rho action in E.coli and Salmonella, as well as several lines of investigation of the role of Rho in the conditional expression of bacterial genomes.