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A transcrição pela RNA polimerase II (RNA polimerase B) e a sínteses de proteínas são os mais importantes processos metabólicos em células eucarióticas, e estão envolvidas no controle da expressão gênica. Trichoderma reesei foi utilizado como modelo de estudo para o desenvolvimento deste estudo. Este fungo filamentoso é um microrganismo que vem sendo utilizado por vários laboratórios no mundo para o estudo dos diversos processos biológicos básicos devido à sua grande importância biotecnológica. Foi estabelecido por nosso grupo de pesquisa um banco de dados ESTs (\"Expressed Sequence Tags\") para este microrganismo e, por meio da técnica de \"microarrays\" de cDNAs, determinou-se a reposta transcricional de T. reesei em função da disponibilidade de oxigênio e glicose, assim como a alguns estresses ambientais. Com base nesses resultados foram escolhidos alguns transcritos afetados pela limitação de oxigênio, tais como o gene btf3. Este gene codifica para a proteína reguladora BTF3 (Fator Transcricional 3 da RNA polimerase B), muito conservada em eucariotos, envolvida na transcrição de vários promotores da classe II e que faz parte do complexo que se liga aos polipeptídios nascentes (NAC). Com o intuito de estudar a funcionalidade do gene btf3 em condições normais e em choque térmico foi realizada uma análise transcricional comparativa em larga escala da cepa selvagem de T. reesei QM9414 e do mutante nocaute do gene btf3. A expressão de aproximadamente 2.000 genes foi analisada, por meio de \"microarrays\", em células submetidas ao estresse por choque térmico produzido pelo incremento da temperatura de cultura a 40°C. O nocaute do gene btf3 produziu o incremento da expressão dos genes das vias metabólicas primárias (ND4 e FBA), da defesa celular (DnaJ, HSP70 e RCI) e da síntese de proteínas (eIF2); enquanto que reprimiu genes da estrutura celular (HFBII) e da síntese de RNA (ATF21). No choque térmico, genes que codificam para proteínas associadas com a defesa celular, como as chaperonas Hsp70 e DnaJ, tiveram sua expressão induzida enquanto que proteínas associadas à divisão celular, como histonas e septina B, e à síntese de proteínas, como as proteínas ribossomais, foram reprimidas em ambas as cepas como resultado do estresse. Os resultados obtidos na análise por \"microarray\" foram validados através de PCR quantitativo em tempo real (qPCR). Estes resultados sugerem que BTF3 possa atuar como repressor de alguns genes transcritos pela RNA polimerase II. / Transcription by RNA polymerase II (RNA polymerase B) and protein synthesis are the most important metabolic processes in eukaryotic cells, and they are involved in the control of gene expression. Trichoderma reesei was used as model of study for the development of this study. This filamentous fungus is a microorganism that has been used by some laboratories around the world for the study of diverse basic biological questions due to its great biotechnological importance. We had established a data base of ESTs (Expressed Sequence Tags) for this microorganism and, through the technique of cDNA microarray, we had determined the transcriptional response of T. reesei to oxygen and glucose availability, as well as some environmental stresses. Based on such studies we chose some transcripts affected by oxygen limitation such as the btf3 gene, for more detailed investigations. This gene codes for the BTF3 regulatory protein (RNA Polymerase B Transcription Factor 3), a conserved transcriptional factor among eukaryotes that is involved in the transcription of several class II promoters and is part of the nascent polypeptide-associated complex (NAC). In order to study the functionality of the btf3 gene in normal and heat shock conditions, a large-scale transcriptional comparative analysis between T. reesei wildtype strain QM9414 and the btf3 knockout mutant was executed. The expression of approximately 2,000 genes was analyzed using microarrays in cells submitted to heat stress produced by culture temperature increment to 40°C. The knockout of btf3 produces the increment of the expression of genes involved with the primary metabolism pathways (ND4 and FBA), cellular defense (DnaJ, HSP70 and RCI) and protein synthesis (eIF2); whereas it repressed genes related to the structure cell (HFBII) and RNA synthesis (ATF21). In heat shock, genes that encode Hsp70 and DnaJ proteins, associated to cellular defense, as chaperones, had their expression induced. On the other hand, genes for proteins associated to cellular division, such as histones and septin B, and those related to protein synthesis, such as ribossomal proteins were transcriptionally repressed in both strains as a result of the stress. The results obtained in the microarray analysis were validated through quantitative real-time PCR (qPCR). These results suggest that BTF3 can act as a repressor for some genes transcribed by RNA polymerase B.

A transcrição pela RNA polimerase II (RNA polimerase B) e a sínteses de proteínas são os mais importantes processos metabólicos em células eucarióticas, e estão envolvidas no controle da expressão gênica. Trichoderma reesei foi utilizado como modelo de estudo para o desenvolvimento deste estudo. Este fungo filamentoso é um microrganismo que vem sendo utilizado por vários laboratórios no mundo para o estudo dos diversos processos biológicos básicos devido à sua grande importância biotecnológica. Foi estabelecido por nosso grupo de pesquisa um banco de dados ESTs (\"Expressed Sequence Tags\") para este microrganismo e, por meio da técnica de \"microarrays\" de cDNAs, determinou-se a reposta transcricional de T. reesei em função da disponibilidade de oxigênio e glicose, assim como a alguns estresses ambientais. Com base nesses resultados foram escolhidos alguns transcritos afetados pela limitação de oxigênio, tais como o gene btf3. Este gene codifica para a proteína reguladora BTF3 (Fator Transcricional 3 da RNA polimerase B), muito conservada em eucariotos, envolvida na transcrição de vários promotores da classe II e que faz parte do complexo que se liga aos polipeptídios nascentes (NAC). Com o intuito de estudar a funcionalidade do gene btf3 em condições normais e em choque térmico foi realizada uma análise transcricional comparativa em larga escala da cepa selvagem de T. reesei QM9414 e do mutante nocaute do gene btf3. A expressão de aproximadamente 2.000 genes foi analisada, por meio de \"microarrays\", em células submetidas ao estresse por choque térmico produzido pelo incremento da temperatura de cultura a 40°C. O nocaute do gene btf3 produziu o incremento da expressão dos genes das vias metabólicas primárias (ND4 e FBA), da defesa celular (DnaJ, HSP70 e RCI) e da síntese de proteínas (eIF2); enquanto que reprimiu genes da estrutura celular (HFBII) e da síntese de RNA (ATF21). No choque térmico, genes que codificam para proteínas associadas com a defesa celular, como as chaperonas Hsp70 e DnaJ, tiveram sua expressão induzida enquanto que proteínas associadas à divisão celular, como histonas e septina B, e à síntese de proteínas, como as proteínas ribossomais, foram reprimidas em ambas as cepas como resultado do estresse. Os resultados obtidos na análise por \"microarray\" foram validados através de PCR quantitativo em tempo real (qPCR). Estes resultados sugerem que BTF3 possa atuar como repressor de alguns genes transcritos pela RNA polimerase II. / Transcription by RNA polymerase II (RNA polymerase B) and protein synthesis are the most important metabolic processes in eukaryotic cells, and they are involved in the control of gene expression. Trichoderma reesei was used as model of study for the development of this study. This filamentous fungus is a microorganism that has been used by some laboratories around the world for the study of diverse basic biological questions due to its great biotechnological importance. We had established a data base of ESTs (Expressed Sequence Tags) for this microorganism and, through the technique of cDNA microarray, we had determined the transcriptional response of T. reesei to oxygen and glucose availability, as well as some environmental stresses. Based on such studies we chose some transcripts affected by oxygen limitation such as the btf3 gene, for more detailed investigations. This gene codes for the BTF3 regulatory protein (RNA Polymerase B Transcription Factor 3), a conserved transcriptional factor among eukaryotes that is involved in the transcription of several class II promoters and is part of the nascent polypeptide-associated complex (NAC). In order to study the functionality of the btf3 gene in normal and heat shock conditions, a large-scale transcriptional comparative analysis between T. reesei wildtype strain QM9414 and the btf3 knockout mutant was executed. The expression of approximately 2,000 genes was analyzed using microarrays in cells submitted to heat stress produced by culture temperature increment to 40°C. The knockout of btf3 produces the increment of the expression of genes involved with the primary metabolism pathways (ND4 and FBA), cellular defense (DnaJ, HSP70 and RCI) and protein synthesis (eIF2); whereas it repressed genes related to the structure cell (HFBII) and RNA synthesis (ATF21). In heat shock, genes that encode Hsp70 and DnaJ proteins, associated to cellular defense, as chaperones, had their expression induced. On the other hand, genes for proteins associated to cellular division, such as histones and septin B, and those related to protein synthesis, such as ribossomal proteins were transcriptionally repressed in both strains as a result of the stress. The results obtained in the microarray analysis were validated through quantitative real-time PCR (qPCR). These results suggest that BTF3 can act as a repressor for some genes transcribed by RNA polymerase B.

Le blé tendre, Triticum aestivum, est une des céréales les plus cultivées dans le monde. Le changement climatique qui se développe actuellement contraint fortement les cultures et altère leur rendement. La compréhension des mécanismes de réponse du blé tendre aux stress abiotiques est donc une problématique d’actualité. Plusieurs grandes familles de facteurs de transcription, dont la famille NAC,interviennent dans le développement de la plante et dans sa réponse aux stress environnementaux. Cette thèse, structurée en 3 volets, est ciblée sur l’étude de la famille NAC chez le blé tendre : les TaNAC. Dans un premier temps, nous avons étudié la structuration génomique et phylogénétique des 488 membres de la famille TaNAC, recensés à partir de la base de données la plus récente du blé tendre.Nous avons aussi étudié l’histoire évolutive de cette famille, qui a été marquée par des événements de duplication et de rétroposition. Enfin, une analyse de sa diversité allélique a permis d’identifier des gènes qui présentent des SNP montrant une forte association avec des paramètres d’accumulation des protéines de réserve dans le grain. Le deuxième chapitre de cette thèse a porté sur l’étude de l’expression de ces 488 gènes TaNAC dans plusieurs organes et en réponse aux stress thermique et sécheresse. Une analyse globale a été réalisée à partir de données bio-informatiques, suivie d’une étude in planta de l’expression d’une sélection de 23 gènes. Les profils d’expression obtenus ont révélé l’existence de 4 gènes TaNAC, encore jamais décrits dans la littérature et qui interviennent dans le développement du grain de blé tendre mais aussi dans sa réponse adaptative à plusieurs stress abiotiques. Le troisième volet de cette thèse a donc porté sur la caractérisation génétique, moléculaire et physiologique de ces 4 facteurs de transcription TaNAC. Ils appartiennent à un clade rassemblant des séquences présentant des similitudes génomique et structurale. De plus, ils sont localisés dans le noyau et leurs profils d’expression sont similaires, avec toutefois un niveau variable entre gènes et entre homéologues pour chaque gène. En réponse à un stress thermique modéré, ce profil d’expression est accéléré au cours du développement du grain ; le stade 120°Cj étant le stade clé qui montre la plus grande différence d’expression de ces gènes entre les conditions contrôle et stressée. Pour des raisons techniques, la production de plantes transgéniques sur- et sous-exprimant ces gènes n’a pas permis de valider l’implication de ces 4 TaNAC dans le développement du grain et en réponse à la température. Une analyse de génétique d’association a toutefois permis de mettre en évidence un lien entre des marqueurs moléculaires situés dans ces gènes et l’accumulation des protéines de réserve.Globalement, les résultats obtenus ont montré que des membres de la famille TaNAC sont impliqués dans le développement du blé tendre et dans sa réponse aux stress abiotiques. Plus particulièrement, 4 facteurs de transcription TaNAC semblent jouer un rôle clé dans l’accumulation des protéines dans le grain en réponse à un stress thermique modéré. / Bread wheat, Triticum aestivum, is one of the most cultivated cereal in the world. The climate change that is currently developing strongly constrains crops and impairs their yield. Understanding the wheat response mechanisms to abiotic stresses is therefore a current issue. Several major families of transcription factors, including the NAC family, are involved in the plant development and its response to environmental stresses. This thesis, structured in three parts, is focused on the study of the NAC family in bread wheat (TaNAC).First, we studied the genomic and phylogenetic structure of the 488 members of the TaNAC family identified from the latest database of bread wheat. We also studied the evolutionary history of this family, which was marked by duplication and retroposition events. Finally, an analysis of its allelic diversity allows us to identify genes with SNP showing a strong association with storage protein accumulation parameters in the grain. In a second part, we studied the expression of these 488 TaNAC genes in several organs and in response to heat and drought. An overall analysis was performed using bioinformatic data, followed by an in planta study of the expression of a selection of 23 genes. The expression profiles revealed that four TaNAC genes, never described in the literature, are involved in the wheat grain development but also in its adaptive response to several abiotic stresses. In a third part, we focused on the genetic, molecular and physiological characterization of these four TaNAC transcription factors. They belong to a clade gathering sequences with genomic and structural similarities. Moreover, they are localized in the nucleus and their expression profiles are similar, with a variable level between genes and between homeologs for each gene. In response to moderate heat stress, this expression profile is accelerated during grain development and a key stage at 120°Cj was identified, it shows the greatest difference in genes expression level between control and stressed conditions. For technical reasons, the production of transgenic plants over- and under-expressing these genes did not validate the involvement of these 4 TaNAC in grain development and in its temperature response. An association genetic analysis, however, showed a link between molecular markers located in these genes and the storage proteins accumulation. Overall, the results showed that members of the TaNAC family are involved in the bread wheat development and its response to abiotic stresses. In particular, four TaNAC transcription factors appear to play a key role in grain protein accumulation in response to a moderate heat stress.

Essa pesquisa teve por objetivo compreender a criação e atuação do Núcleo de Arte Contemporânea da Universidade Federal da Paraíba (NAC/UFPB) no período de 1978 a 1985. Seu surgimento está inserido num momento em que o Brasil vivia o complexo processo de abertura política e quando o sistema da arte, marcado por uma produção de caráter experimental, passava por reconfigurações tanto nas funções de suas instituições culturais quanto nos conceitos, ideias e práticas artísticas. A hipótese aqui defendida é que apesar de sua criação está diretamente relacionada com as diretrizes da Política Nacional de Cultura (PNC) e do Ministério da Educação e Cultura (MEC) para as universidades brasileiras, as presenças do crítico Paulo Sérgio Duarte e do artista Antonio Dias, responsáveis tanto pela concepção de sua proposta como por sua divulgação na cena artística nacional, possibilitou que o Núcleo colocasse em prática um modelo inovador no âmbito institucional nordestino, com o enfoque na produção e difusão da arte experimental brasileira. Também verificou-se até que ponto o objetivo do NAC/UFPB de atuar como um centro formador, difusor e fomentador da arte contemporânea na Paraíba se efetivou; e refletiu-se ainda sobre possíveis razões para a diminuição de suas atividades e transformação de sua proposta a partir de 1981. / This research\'s purpose is to analyze the creation of the Contemporary Art Center of the Federal University of Paraíba (Núcleo de Arte Contemporânea da Universidade Federal da Paraíba -NAC/UFPB) as well as its roles throughout 1978 and1985. This institution emerges when Brazil was going through a complex process of political openness. Meanwhile, the art system, marked by the presence of experimental artistic practices, was going through a series of reconfigurations concerning the cultural institution\'s functions and its concepts, ideals and artistic practices.The research\'s hypothesis is that despite the fact that NAC\'s creation was directly related to the National Cultural Politics (Política Nacional de Cultura - PNC) and Culture and Education Ministry (Ministério da Educação e Cultural - MEC) directives regarding Brazilian universities, it was the presence of Paulo Sérgio Duarte (critic) and of the artist Antonio Dias, both responsible for the conception of the institution\'s motions and for inserting it into the national artistic scene, that made it possible to enact an innovative model considering the northeastern institutional context. This is to be considered focusing on the production and dissemination of Brazilian experimental art. One of the central issues of this research was to identify through what extend had NAC fulfilled its objective of becoming an educational center that also disseminates and foments contemporary art in the state of Paraíba. In addition to that, one of the highpoints of the research relies on analyzing what had caused a decrease in NAC\'s activities, as well as a noticeable transformation of its main purposes and objectives in 1981.

Essa pesquisa teve por objetivo compreender a criação e atuação do Núcleo de Arte Contemporânea da Universidade Federal da Paraíba (NAC/UFPB) no período de 1978 a 1985. Seu surgimento está inserido num momento em que o Brasil vivia o complexo processo de abertura política e quando o sistema da arte, marcado por uma produção de caráter experimental, passava por reconfigurações tanto nas funções de suas instituições culturais quanto nos conceitos, ideias e práticas artísticas. A hipótese aqui defendida é que apesar de sua criação está diretamente relacionada com as diretrizes da Política Nacional de Cultura (PNC) e do Ministério da Educação e Cultura (MEC) para as universidades brasileiras, as presenças do crítico Paulo Sérgio Duarte e do artista Antonio Dias, responsáveis tanto pela concepção de sua proposta como por sua divulgação na cena artística nacional, possibilitou que o Núcleo colocasse em prática um modelo inovador no âmbito institucional nordestino, com o enfoque na produção e difusão da arte experimental brasileira. Também verificou-se até que ponto o objetivo do NAC/UFPB de atuar como um centro formador, difusor e fomentador da arte contemporânea na Paraíba se efetivou; e refletiu-se ainda sobre possíveis razões para a diminuição de suas atividades e transformação de sua proposta a partir de 1981. / This research\'s purpose is to analyze the creation of the Contemporary Art Center of the Federal University of Paraíba (Núcleo de Arte Contemporânea da Universidade Federal da Paraíba -NAC/UFPB) as well as its roles throughout 1978 and1985. This institution emerges when Brazil was going through a complex process of political openness. Meanwhile, the art system, marked by the presence of experimental artistic practices, was going through a series of reconfigurations concerning the cultural institution\'s functions and its concepts, ideals and artistic practices.The research\'s hypothesis is that despite the fact that NAC\'s creation was directly related to the National Cultural Politics (Política Nacional de Cultura - PNC) and Culture and Education Ministry (Ministério da Educação e Cultural - MEC) directives regarding Brazilian universities, it was the presence of Paulo Sérgio Duarte (critic) and of the artist Antonio Dias, both responsible for the conception of the institution\'s motions and for inserting it into the national artistic scene, that made it possible to enact an innovative model considering the northeastern institutional context. This is to be considered focusing on the production and dissemination of Brazilian experimental art. One of the central issues of this research was to identify through what extend had NAC fulfilled its objective of becoming an educational center that also disseminates and foments contemporary art in the state of Paraíba. In addition to that, one of the highpoints of the research relies on analyzing what had caused a decrease in NAC\'s activities, as well as a noticeable transformation of its main purposes and objectives in 1981.

Maternal diabetes is associated with increased risk of growth disturbances and congenital malformations. The malformations rate in the offspring of diabetic mothers is 2-3 fold higher compared to infants of nondiabetic mothers. In this thesis we have investigated the role of the protein kinase C (PKC) pathway and the apoptotic machinery in embryopathy. We investigated the involvement of PKC isoforms in the embryopathy of diabetic rat pregnancy. Embryos of diabetic rats showed altered activity and protein distribution of several PKC isoforms compared with embryos of normal rats. Using whole embryo culture we found increased activity of PKC-delta and PKC-zeta after 24h of culture and increased rate of malformations and growth retardation in embryos cultured in high glucose concentration compared to embryos cultured in low glucose concentration. Addition of α-cyano-4-cinnamic acid and N-acetylcysteine to the culture medium normalized malformations and growth retardations whereas specific PKC-inhibitors abolished malformations and partly restored the growth retardations. All treatment normalized glucose-induced increase of PKC activity. Estimated occurrence of apoptosis in embryos of diabetic rats and in embryonic cells exposed to high glucose concentration showed increased rate of pro-apoptotic markers. The increased apoptosis in the high glucose exposed embryonic cells was normalized by supplementation of N-acetylcysteine or apoptosis inhibitor. Treatment with vitamin E and folic acid to diabetic pregnant rats decreased diabetes-induced malformations and resorptions, concomitant with normalization of apoptotic protein levels. These results suggest that oxidative stress is augmented in embryos of diabetic rats and that it also plays a role in the activation of PKC and apoptosis. We used antioxidative treatment with beneficial effect although we could not completely abolish the embryonic demise; this may indicate that other mechanisms are involved in diabetic embryopathy. Further studies are needed to develop multi-nutrient dietary supplement to eliminate embryonic abnormalities induced by maternal diabetes.

Wheat is the most important grain crop grown in our country providing greatest part of the daily nutritional requirement. Abiotic factors including salinity, drought, cold and heat stresses affect quality and yield of wheat varieties used for the production of both bread and pasta flour. NAC proteins form one of the widest families of plant specific transcription factors. Members of this family are related with development, defense and abiotic stress responses. TaNAC69-1 and TtNAM-B2 genes were isolated from T.aestivum and T.turgidum, respectively. Then they were cloned into different monocot and dicot expression vectors to be used for further wheat and tobacco genetic transformation studies. To understand effects of salinity, drought, cold and heat stresses on expression profiles of TaNAC69-1 and TtNAM-B2 genes, quantitative real time PCR was performed. The time series expression profiles of TaNAC69-1 show that it was signi

No description available.