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No description available.

<p>Recent advances in gene targeting technology have significantly shaped modern-day mouse genetics, as they allow for the accurate analysis of gene function <em>in vivo</em>. By capitalizing on conventional methodologies that are based on homologous recombination, the advent of artificially engineered nucleases, like transcription activator-like effector nucleases (TALENs), enables precise genome editing without the need for conventional targeting vectors, which typically possess long “arms” of homology that are difficult to work with, even with recombineering strategies employing bacterial artificial chromosomes. Unlike traditional techniques, these novel nucleases can be engineered in less than a week and together with compact targeting vectors, can be used to easily manipulate almost any locus in the mouse genome.</p> <p>The current selection of commercially available antibodies makes it difficult to assess the specific roles of protein isoforms during early development. The Tcf/Lef family of transcription factors comprise of key downstream effector proteins of the canonical Wnt/β-catenin signal transduction cascade. This pathway is implicated in the regulation of self-renewal and is dysregulated in a number of human diseases including cancers. Among the Tcf/Lef factors, Tcf3 has been heavily studied in mouse embryonic stem cells, due at least in part to the observation that its transcript levels are expressed at the highest levels compared to the others. Recently, it was proposed that a switch takes place between a repressive state mediated by Tcf3 to an activating β-catenin-Tcf1 complex in response to Wnt signals. Here, we use TALEN technology to introduce an epitope tag at the endogenous locus of <em>mTcf7</em>, the gene encoding the Tcf1 protein. By tagging the N-terminus of full-length and N-terminally truncated dominant-negative variants of Tcf1, we establish a tool to better study a previously unappreciated role for Tcf1 in regulating embryonic stem cell self-renewal and differentiation. Furthermore, we also show that the tagged variants generated exhibit similar protein expression levels to those of wild-type controls, and display nuclear localization as expected.</p> / Master of Science (MSc)

The dissertation is following both theoretical and practical sides of Victor Burgin's early work. The structure of this thesis mainly reflects a hybrid attitude of the artist/theorist - the text digress from theoretical comments to related art works which are arranged chronologically. The principal focus lies in Burgin's concers for ideological, social and cultural impacts of photographic advertising practice in Great Britain during the 1970s which he assesed through theories derived from marxism, semiology and psychoanalysis. Keywords: Victor Burgin, photography theory, minimal art, conceptual art, cognitive science, semiotics, modernism, postmodernism, LEF (Left Front of the Arts), marxism, psychoanalysis, feminism

Le cisplatine (ou cis-diammine, dichloro-platine) est l'un des composés chimiques les plus utilisés actuellement en chimiothérapie anticancéreuse. Depuis la description de ses propriétés anticancéreuses par B. Rosenberg en 1965 de nombreux travaux ont été effectués a n de décrire le mécanisme d'action lui conférant ses propriétés antitumorales. A travers une approche originale couplant modélisation et travail expérimental, les recherches réalisées durant ma thèse ont permis d'élucider le comportement dynamique d'un adduit platiné sur la séquence 5'-GCCG*G*GTCGC-3' / 5'-GCGACCCGGC-3' (G* représente une guanine platinée). Cette structure a été comparée à celle de l'adduit ADN-cisplatine déterminée précédemment au laboratoire sur la séquence G*G*A. Nous avons ainsi étudié l'influence d'une guanine adjacente en 3' au pontage GG-Pt sur la structure de l'adduit. Il s'agit de la première étude structurale sur un adduit du cisplatine avec la séquence GGG. Même si l'a nité de la séquence GGG et des sites contenant Gn (n>= 3) pour le platine (II) est connue depuis longtemps, ses adduits avec le cisplatine n'ont pas encore été étudiés par RMN à cause des problèmes posés par leur puri cation. Cette étude de l'adduit G*G*G par RMN a été confrontée à la description dynamique de cet adduit, calculée par simulation. La paramétrisation du champ de force parm 98 a été spéci quement a née pour mieux décrire l'environnement de l'atome du platine. La confrontation entre la simulation de l'adduit G*G*G-Pt et les données issues de l'étude par RMN a permis de valider notre paramétrisation. Pour déterminer les proportions précises des sous-états BI et BII de l'ADN, une méthode novatrice a été mise au point. Celle-ci est basée sur la combinaison de quatre distances inter-protons H2'(n)-H8(n), H1'(n)-H6/8(n+1), H2'(n)-H6/8(n+1) et H2''(n)-H6/8(n+1) qui permet de discriminer les deux sous-conformations. Ces améliorations du champ de force et de la méthode de détermination des sous-conformations BI/BII ont permis la description ne du comportement de l'adduit couplé à l'ADN, ce qui nous a servi pour étudier le mécanisme anti-tumoral du cisplatine. En effet la reconnaissance de l'ensemble cisplatine-ADN par une protéine (Lymhoïd Enhanced Factor I - LEF I) pourrait activer les voies métaboliques de la cellule cancéreuse conduisant vers l'apoptose ou vers la réparation de la tumeur. La simulation de l'ensemble ADN-protéine (sans cisplatine) a permis de présenter le mode de reconnaissance de la protéine sur la déformation ainsi que la mise en évidence de l'implication d'une molécule d'eau dans celui-ci. Les études sur le cisplatine fixé sur son ADN cible nous ayant apporté de nombreuses connaissances sur les déformations engendrées, nous avons validé la déformation structurale formée par un autre complexe de platine, le pyrazolato-bis-platine. Ce composé a été conçu de novo pour induire une déformation faible de son ADN cible a n de provoquer une réponse cellulaire différente de celle engendrée par le cisplatine. La simulation a indiqué que ce complexe induit une faible courbure de l'ADN et une déformation globale différente de celle du cisplatine, ce qui exclut le même mode de reconnaissance. Comme expérimentalement le complexe pyrazolato possède une activité anti-tumorale, les simulations effectuées suggèrent donc que le mode d'action au niveau cellulaire est différent du cisplatine. Les travaux réalisés lors de ma thèse ont permis d'améliorer la compréhension des déformations ADN-cisplatine, ADN-cisplatine-protéine et de perfectionner la description des composés platinés dans le champ de force parm 98 (puis parm 99) du logiciel de modélisation moléculaire AMBER.

A soja é a cultura de grãos mais importante no Brasil. Na safra de 2010/11 ocupou uma área de 24 milhões de hectares, se destacando como principal oleaginosa produzida e consumida no mundo. Alguns fatores podem limitar a produção da soja, entre eles as doenças. A mancha- alvo (Corynespora cassiicola) é frequente nas em todas as regiões produtoras de soja no Brasil e nos últimos anos tem se atribuído prejuízos crescentes à doença. Os objetivos deste trabalho foram: determinar a faixa ideal de temperatura para o crescimento micelial de diferentes isolados de C. cassiicola; verificar a esporulação em função do meio de cultura; avaliar a germinação de conídios sob diferentes períodos de molhamento foliar; estudar o efeito da temperatura e molhamento foliar nos componentes monocíclicos e realizar estudos de quantificação de danos. Para avaliar o efeito da temperatura no crescimento micelial, diferentes isolados foram mantidos nas temperaturas de 5°C, 10°C, 15°C, 20°C, 25°C, 30°C e 35°C. A temperatura mínima e máxima estimada pela função beta generalizada para o crescimento micelial foi de 6,9°C e 33°C, respectivamente. A esporulação foi estudada nos meios de cultura BDA e Czapek. Os dados obtidos foram comparados por meio do teste Scott-Knott (P<0,05). A produção de conídios foi variável em função do isolado, tanto em meio BDA como Czapek. O ensaio de germinação foi feito em folhas de soja utilizando-se diferentes períodos de molhamento foliar (2, 6, 12, 24, 48 e 72 horas). A contagem de conídios germinados foi feita em microscópio eletrônico de varredura. A germinação de conídios na superfície das folhas foi verificada a partir do período de 6 horas. Para o estudo dos componentes monocíclicos as temperaturas testadas foram 10ºC, 15ºC, 20ºC, 25 ºC e 30ºC e os períodos de molhamento foliar foram 12, 24, 48 e 72 horas. As variáveis quantificadas foram a severidade, o número e o diâmetro das lesões. Os dados foram ajustados às funções beta generalizada e monomolecular. A temperatura mínima, máxima e ótima capazes de promover o desenvolvimento da mancha-alvo foram de 18°C, 32°C e 27°C, respectivamente. O período de molhamemto foliar de 48 horas resultou em maior desenvolvimento da doença. No ensaio de quantificação de danos, cultivares comerciais foram semeadas em duas épocas. Os componentes avaliados em campo foram: a severidade, a área foliar, o indice vegetativo da diferença normalizada (NDVI) e a produtividade (kg ha-1). Com o uso destes dados foram calculadas a área abaixo da curva de progresso da doença (AACPD), a área abaixo da curva de progresso do índice de área foliar (AULIAPC), o indice de área foliar (LAI), o indice de área foliar sadia (HLAI), a duração da área foliar sadia (HAD) e a absorção da área foliar sadia (HAA). Neste ensaio verificou-se que valores de severidade de até 37% no dossel inferior não causam danos no patossistema C.cassicola - soja. As variáveis HLAI e AULAIPC se correlacionaram com a produtividade e podem ser úteis para estudos futuros de quantificação de danos para este patossistema. / Soybean is the most important grain crop in Brazil. The production of 2010/11 occupied an area of 24 million hectares, becoming the most important oilseed produced and consumed worldwide. Some factors, such as diseases, may limit soybean production. The target spot caused by Corynespora cassiicola is frequent in all soybean producing regions in Brazil and in the past years, an increasing loss has been assigned to it. The aims of the present study were to determine the ideal temperature range for mycelial growth of different isolates of C. cassiicola; verify the sporulation in relation to the culture medium; evaluate the conidia germination under different periods of leaf wetness; study the effect of the temperature and the leaf wetness on the monocyclic components and carry out studies of crop loss in the field. In order to evaluate the effect of the temperature on the mycelial growth, different isolates were cultivated at the temperatures of 5°C, 10°C, 15°C, 20°C, 25°C, 30°C and 35°C. The minimum and maximum estimated temperature by the beta function to provide C.cassiicola mycelial growth was 6.9 °C and 33 °C, respectively. The sporulation was analyzed in PDA and Czapek culture media. The results obtained were compared through the Scott-Knott test (P <0.05). The conidia production varied according to each isolate on both PDA and Czapek medias. The germination test was carried out in soybean leaves using different leaf wetness periods (0, 12, 24, 48 and 72 hours). The germinated conidia measurement was done in a scanning electron microscope. The conidia germination on the leaves surface was observed from 6 hours. The temperatures used to study the monocyclic components were 10 º C, 15 º C, 20 º C, 25 º C and 30 º C and the leaf wetness periods were 12, 24, 48 and 72 hours. The variables quantified were severity, number and diameter of lesions. The data were adjusted to the generalized beta and monomolecular functions. The minimum, maximum and optimum temperature able to promote the development of target spot in soybean leaves were 18 ° C, 32 ° C and 27 ° C, respectively. The 48- hour leaf wetness resulted in greater development of the disease. For damage quantification, commercial cultivars were sown in two sowing times. The components evaluated in the field were: severity, leaf area, normalized difference vegetation index (NDVI) and grain yield (kg ha-1). Using these data, it was calculated the area under disease progress curve (AUDPC), area under the leaf area index progress curve (AULIAPC), leaf area index (LAI), healthy leaf area index (HLAI), healthy area duration (HAD) and healthy area absorption area (HAA). The severity values up to 37% in the lower canopy do not cause crop loss in C.cassicola - soybean pathosystem .The variables HLAI and AULAIPC correlated with grain yield and may be useful for future studies of crop loss for this pathosystem.

A soja é a cultura de grãos mais importante no Brasil. Na safra de 2010/11 ocupou uma área de 24 milhões de hectares, se destacando como principal oleaginosa produzida e consumida no mundo. Alguns fatores podem limitar a produção da soja, entre eles as doenças. A mancha- alvo (Corynespora cassiicola) é frequente nas em todas as regiões produtoras de soja no Brasil e nos últimos anos tem se atribuído prejuízos crescentes à doença. Os objetivos deste trabalho foram: determinar a faixa ideal de temperatura para o crescimento micelial de diferentes isolados de C. cassiicola; verificar a esporulação em função do meio de cultura; avaliar a germinação de conídios sob diferentes períodos de molhamento foliar; estudar o efeito da temperatura e molhamento foliar nos componentes monocíclicos e realizar estudos de quantificação de danos. Para avaliar o efeito da temperatura no crescimento micelial, diferentes isolados foram mantidos nas temperaturas de 5°C, 10°C, 15°C, 20°C, 25°C, 30°C e 35°C. A temperatura mínima e máxima estimada pela função beta generalizada para o crescimento micelial foi de 6,9°C e 33°C, respectivamente. A esporulação foi estudada nos meios de cultura BDA e Czapek. Os dados obtidos foram comparados por meio do teste Scott-Knott (P<0,05). A produção de conídios foi variável em função do isolado, tanto em meio BDA como Czapek. O ensaio de germinação foi feito em folhas de soja utilizando-se diferentes períodos de molhamento foliar (2, 6, 12, 24, 48 e 72 horas). A contagem de conídios germinados foi feita em microscópio eletrônico de varredura. A germinação de conídios na superfície das folhas foi verificada a partir do período de 6 horas. Para o estudo dos componentes monocíclicos as temperaturas testadas foram 10ºC, 15ºC, 20ºC, 25 ºC e 30ºC e os períodos de molhamento foliar foram 12, 24, 48 e 72 horas. As variáveis quantificadas foram a severidade, o número e o diâmetro das lesões. Os dados foram ajustados às funções beta generalizada e monomolecular. A temperatura mínima, máxima e ótima capazes de promover o desenvolvimento da mancha-alvo foram de 18°C, 32°C e 27°C, respectivamente. O período de molhamemto foliar de 48 horas resultou em maior desenvolvimento da doença. No ensaio de quantificação de danos, cultivares comerciais foram semeadas em duas épocas. Os componentes avaliados em campo foram: a severidade, a área foliar, o indice vegetativo da diferença normalizada (NDVI) e a produtividade (kg ha-1). Com o uso destes dados foram calculadas a área abaixo da curva de progresso da doença (AACPD), a área abaixo da curva de progresso do índice de área foliar (AULIAPC), o indice de área foliar (LAI), o indice de área foliar sadia (HLAI), a duração da área foliar sadia (HAD) e a absorção da área foliar sadia (HAA). Neste ensaio verificou-se que valores de severidade de até 37% no dossel inferior não causam danos no patossistema C.cassicola - soja. As variáveis HLAI e AULAIPC se correlacionaram com a produtividade e podem ser úteis para estudos futuros de quantificação de danos para este patossistema. / Soybean is the most important grain crop in Brazil. The production of 2010/11 occupied an area of 24 million hectares, becoming the most important oilseed produced and consumed worldwide. Some factors, such as diseases, may limit soybean production. The target spot caused by Corynespora cassiicola is frequent in all soybean producing regions in Brazil and in the past years, an increasing loss has been assigned to it. The aims of the present study were to determine the ideal temperature range for mycelial growth of different isolates of C. cassiicola; verify the sporulation in relation to the culture medium; evaluate the conidia germination under different periods of leaf wetness; study the effect of the temperature and the leaf wetness on the monocyclic components and carry out studies of crop loss in the field. In order to evaluate the effect of the temperature on the mycelial growth, different isolates were cultivated at the temperatures of 5°C, 10°C, 15°C, 20°C, 25°C, 30°C and 35°C. The minimum and maximum estimated temperature by the beta function to provide C.cassiicola mycelial growth was 6.9 °C and 33 °C, respectively. The sporulation was analyzed in PDA and Czapek culture media. The results obtained were compared through the Scott-Knott test (P <0.05). The conidia production varied according to each isolate on both PDA and Czapek medias. The germination test was carried out in soybean leaves using different leaf wetness periods (0, 12, 24, 48 and 72 hours). The germinated conidia measurement was done in a scanning electron microscope. The conidia germination on the leaves surface was observed from 6 hours. The temperatures used to study the monocyclic components were 10 º C, 15 º C, 20 º C, 25 º C and 30 º C and the leaf wetness periods were 12, 24, 48 and 72 hours. The variables quantified were severity, number and diameter of lesions. The data were adjusted to the generalized beta and monomolecular functions. The minimum, maximum and optimum temperature able to promote the development of target spot in soybean leaves were 18 ° C, 32 ° C and 27 ° C, respectively. The 48- hour leaf wetness resulted in greater development of the disease. For damage quantification, commercial cultivars were sown in two sowing times. The components evaluated in the field were: severity, leaf area, normalized difference vegetation index (NDVI) and grain yield (kg ha-1). Using these data, it was calculated the area under disease progress curve (AUDPC), area under the leaf area index progress curve (AULIAPC), leaf area index (LAI), healthy leaf area index (HLAI), healthy area duration (HAD) and healthy area absorption area (HAA). The severity values up to 37% in the lower canopy do not cause crop loss in C.cassicola - soybean pathosystem .The variables HLAI and AULAIPC correlated with grain yield and may be useful for future studies of crop loss for this pathosystem.

Wnt signalling represents an important mechanism participating in control of cellular and developmental processes, including establishment of cell polarity, cell fate specification, stem cell self-renewal, tissue patterning and organogenesis, homeostasis maintenance and regeneration. Misregulation of the Wnt signalling during embryogenesis leads to developmental defects while aberrant activation later in development is associated with degenerative diseases and a number of cancers. The presented PhD thesis is based on four original publications that deal with the post-translational modifications of Wnt ligands and molecular mechanisms contributing to the regulation of a transcriptional profile of the so-called canonical Wnt pathway. Wnt signalling pathway is used repetitively both in time and different cellular contexts throughout development of multicellular organisms. Inevitably, in each single situation -catenin/TCF complexes, the downstream effectors, induce only subsets of all potential target genes. How this differential tissue- and stage-specific control over various subsets of target genes is achieved with such a limited number of nuclear effectors is not fully understood. Along with the expression of specific LEF/TCF family members or their variants containing different functional domains...