Transcriptional dynamics of the human DMD locus

The human DMD locus encodes dystrophin protein. Absence or reduced levels of dystrophin (DMD or BMD phenotype, respectively) lead to progressive muscle wasting. Little is known about the complex coordination of dystrophin expression and its transcriptional regulation is a field of intense interest. In this work we found that DMD locus harbours multiple long non coding RNAs which orchestrate and control transcription of muscle dystrophin mRNA isoforms. These lncRNAs are tissue-specific and highly expressed during myogenesis, suggesting a possible role in tissue-specific expression of DMD gene isoforms. Their forced ectopic expression in human muscle and neuronal cells leads to a specific and negative regulation of endogenous dystrophin full lenght isoforms. An intriguing aspect regarding the transcription of the DMD locus is the gene size (2.4Mb). The mechanism that ensures the complete synthesis of the primary transcript and the coordinated splicing of 79 exons is still completely unknown. By ChIP-on-chip analyses, we discovered novel regions never been involved before in the transcription regulation of the DMD locus. Specifically, we observed enrichments for Pol II, P-Ser2, P-Ser5, Ac-H3 and 2Me-H3K4 in an intronic region of 3Kb (approximately 21Kb) downstream of the end of DMD exon 52 and in a region of 4Kb spanning the DMD exon 62. Interestingly, this latter region and the TSS of Dp71 are strongly marked by 3Me-H3K36, an histone modification associated with the regulation of splicing process. Furthermore, we also observed strong presence of open chromatin marks (Ac-H3 and 2Me-H3K4) around intron 34 and the exon 45 without presence of RNA pol II. We speculate that these two regions may exert an enhancer-like function on Dp427m promoter, although further investigations are necessary. Finally, we investigated the nuclear-cytoplasmic compartmentalization of the muscular dystrophin mRNA and, specifically, we verified whether the exon skipping therapy could influence its cellular distribution

Computational models of trust

Trust and reputation are key issues in the multi-agent systems domain. As in human societies, software agents must interact with other agents in settings where there is the possibility that they can be exploited. This suggests the need for theoretical and computational models of trust and reputation that can be used by software agents, and accordingly, much research has investigated this issue. The first part of this thesis investigates the conjecture that agents who make decisions in scenarios where trust is important can benefit from the use of a social structure, representing the social relationships that exist between agents. To this end, we present techniques that can be used by agents to initially build and then progressively update such a structure in the light of experience. As the agents interact with other agents they gather information about interactions and relationships in order to build the network of agents and to better understand their social environment. We also show empirical evidence that a trust model enhanced with a social structure representation, used to gather additional information to select trustworthy agents for an agent’s interactions, can improve the trust model’s performance. In the second part of this thesis, we concentrate on the context of coalition formation. Coalition stability is a crucial issue. Stability is the motivation of an agent’s refusal to break from the original coalition and form a new one. Lack of trust in some of the coalition members could induce one agent to leave the coalition. Therefore we address the current model’s limitation by introducing an abstract framework that allows agents to form distrust-free coalitions. Moreover we present measures to evaluate the trustworthiness of the agent with respect to the whole society or to a particular coalition. We also describe a way to combine the trust and distrust relationships to form coalitions which are still distrust-free

O papel crítico da gestão cultural no seio do dispositivo da moda e da indústria do têxtil e do vestuário : O caso de Portugal

A Moda será talvez o dispositivo que melhor consegue transportar o que é a Modernidade, ilustrando o imaginário humano sempre em devir. Em paralelo com a perspetiva humanística, na sua abordagem, têm de se equacionar questões de técnica e, forçosamente, todo um ecossistema cultural. O sistema atual da Moda e do vestuário culmina visivelmente nos progressos atuais da tecnologia e tensões presentes nas principais áreas científicas, de que é expressão o fenómeno da obsolescência. É neste campo operativo, sistema complexo, maduro nos seus equilíbrios e paradigmas, mas também, contradições e colapsos, que se levantam problemas particulares e transversais a outros setores. A UNESCO e outras influentes instituições internacionais preconizam a sustentabilidade e assumem o seu compromisso com o desenvolvimento sustentável. Neste enquadramento, enfrentam-se questões de nível global como a sustentabilidade e a(s) crise(s) dos modelos económicos prevalecentes no Ocidente contemporâneo. Relativamente às prioridades definidas na planificação de projetos no setor da Moda, do têxtil e do vestuário, quando nos circunscrevemos ao território português, urgia realizar-se uma investigação com o objetivo de entender as relações entre as entidades, atores e instituições ativas neste campo. A intenção é aferir possibilidades de Gestão Cultural, partindo de três questões charneiras. Qual o entendimento da sustentabilidade por parte desses intervenientes? Que pontos fracos e oportunidades caracterizam o sistema? Como é que toda esta problematologia se comporta enquanto rede? Em conformidade com o desígnio supra, a metodologia usada para resolver os objetivos consistiu numa conjugação de métodos e de técnicas que atingem atores representativos, graças a um acesso privilegiado ao setor. Concretizou-se uma análise qualitativa através da técnica da entrevista livre acompanhada de guião premeditando desvios, acrescida de duas discussões com grupos focais, dois estágios de observação participativa, a participação em duas conferências e ainda em duas ações de formação. Paralelamente trabalhou-se na divulgação de um inquérito online visando a recolha de dados quantitativos que ajudaram a validar as interpretações da análise qualitativa. O corpus foi dividido em três grupos: o primeiro para a esfera da decisão, o segundo relativo à dos Tecnólogos e o terceiro para a dos Criativos, todos representados num estudo comparativo através de gráficos dimensionais Radar. Observou-se que os atores dos três grupos estão geralmente isolados na sua especificidade. Numa síntese possível, os Criativos aspiram a mais poder, os Engenheiros reconhecem o seu défice de originalidade e os Decisores revelam-se afastados do quotidiano social. Para a Gestão Cultural, abordagem teórico-prático relativamente recente no panorama atual, é crucial reconhecer-se territórios para a sua ação. Assim, nesta investigação, individualizaram-se terrenos concretos onde a Gestão Cultural poderá desenvolver a sua interpretação numa visão pluralista e holística – um ecumenismo cultural – necessária e importante para o ativar ou reativar compromissos no seio do dispositivo da Moda, isto é, novos modos de fazeres e de seres desta dinâmica social. O presente estudo diz respeito a um setor específico e ao caso português, podendo, no entanto, a metodologia desta investigação ser adaptada a qualquer outro âmbito cultural. Aspira-se, em última análise, a uma reversão de comportamentos consuetudinários num setor essencial da economia portuguesa: parar de fazer para melhor projetar e gerir processos, equipamentos e recursos

The 51^{51}Cr neutrino source and Borexino: a desirable marriage

Exposure to a $^{51}$Cr neutrino source as that used in Gallex will provide an excellent overall performance test of Borexino, which should collect about 1400 source induced events, with an initial rate of about 35 counts per day. This will be particularly important if MSW-small-angle turns out to be the solution of the solar neutrino problem. In addition, if an independent, accurate calibration is available, one will have an interesting experiment on neutrino properties: as an example, a neutrino magnetic moment of the order $5\cdot10^{-11}\mu_B$could be detected/excluded at the 90\% C.L.Comment: 7 pages, RevTeX, plus 3 postscripts figures, tarred, compresse

Limits on Electron-Neutrino Oscillations from the GALLEX 51^{51}Cr Source Experiment

The recent result from the chromium source experiment carried out by the GALLEX collaboration implies interesting limits on the parameters $\Delta m^2$ and $\sin^22\theta$ describing neutrino oscillations. Values of $\Delta m^2~>~0.17$ eV$^2$ for maximal mixing and of $\sin^22\theta > 0.38$ for $\Delta m^2 > 1$~eV$^2$ are ruled out at 90\% C.L. This result improves by more than an order of magnitude previous limits on $\Delta m^2$ derived from electron-neutrino oscillation experiments at accelerators.Comment: 6 pages (REVTEX) + one figure (postscript), all in uuencoded forma

Peritoneal and hematogenous metastases of ovarian cancer cells are both controlled by the p90RSK through a self-reinforcing cell autonomous mechanism

The molecular mechanisms orchestrating peritoneal and hematogenous metastases of ovarian cancer cells are assumed to be distinct. We studied the p90RSK family of serine/threonine kinases that lie downstream the RAS-ERK/MAPK pathway and modulate a variety of cellular processes including cell proliferation, survival, motility and invasiveness. We found the RSK1 and RSK2 isoforms expressed in a number of human ovarian cancer cell lines, where they played redundant roles in sustaining in vitro motility and invasiveness. In vivo, silencing of both RSK1 and RSK2 almost abrogated short-term and long-term metastatic engraftment of ovarian cancer cells in the peritoneum. In addition, RSK1/RSK2 silenced cells failed to colonize the lungs after intravenous injection and to form hematogenous metastasis from subcutaneous xenografts. RSK1/RSK2 suppression resulted in lessened ovarian cancer cell spreading on endogenous fibronectin (FN). Mechanistically, RSK1/RSK2 knockdown diminished FN transcription, α5β1 integrin activation and TGF-β1 translation. Reduced endogenous FN deposition and TGF-β1 secretion depended on the lack of activating phosphorylation of the transcription/translation factor YB-1 by p90RSK. Altogether data show how p90RSK activates a self-reinforcing cell autonomous pro-adhesive circuit necessary for metastatic seeding of ovarian cancer cells. Thus, p90RSK inhibitors might hinder both the hematogenous and the peritoneal metastatic spread of human ovarian cancer

Ovarian Cancer Cells in Ascites Form Aggregates That Display a Hybrid Epithelial-Mesenchymal Phenotype and Allows Survival and Proliferation of Metastasizing Cells

Peritoneal metastases are the leading cause of morbidity and mortality in ovarian cancer. Cancer cells float in peritoneal fluid, named ascites, together with a definitely higher number of non neo-neoplastic cells, as single cells or multicellular aggregates. The aim of this work is to uncover the features that make these aggregates the metastasizing units. Immunofluorescence revealed that aggregates are made almost exclusively of ovarian cancer cells expressing the specific nuclear PAX8 protein. The same cells expressed epithelial and mesenchymal markers, such as EPCAM and αSMA, respectively. Expression of fibronectin further supported a hybrid epithelia-mesenchymal phenotype, that is maintained when aggregates are cultivated and proliferate. Hematopoietic cells as well as macrophages are negligible in the aggregates, while abundant in the ascitic fluid confirming their prominent role in establishing an eco-system necessary for the survival of ovarian cancer cells. Using ovarian cancer cell lines, we show that cells forming 3D structures neo-expressed thoroughly fibronectin and αSMA. Functional assays showed that αSMA and fibronectin are necessary for the compaction and survival of 3D structures. Altogether these data show that metastasizing units display a hybrid phenotype that allows maintenance of the 3D structures and the plasticity necessary for implant and seeding into peritoneal lining