The cellular basis of a congenital heart defect Drosophila

RESUMO: Mutações em genes envolvidos na formação do coração e anomalias em qualquer etapa deste processo causam frequentemente malformações cardíacas, que representam o tipo mais comum de defeitos em neonatais, afetando cerca de 1% dos nascimentos por ano. Assim, estima-se que 20 milhões de pessoas sejam portadoras de um defeito cardíaco congénito. O coração da Drosophila melanogaster (mosca-da-fruta), denominado vaso dorsal, é um órgão relativamente simples que actua como uma bomba muscular, contraindo automaticamente para permitir a circulação da hemolinfa através do corpo. A formação do vaso dorsal na mosca é muito semelhante ao desenvolvimento do coração em vertebrados, representando por isso, um poderoso modelo para estudar a rede de genes e os padrões regulatórios relacionados com o desenvolvimento deste órgão. Anteriormente, nós identificámos um gene em Drosophila, darhgef10, fortemente expresso no coração em desenvolvimento e cuja deleção induz anormalidades cardíacas subtis mas prevalentes. Os mutantes para darhgef10 são viáveis e férteis no ambiente controlado de laboratório. Este trabalho teve como objectivos caracterizar fenotipicamente os mutantes nulos para darhgef10, determinar a localização subcelular da proteína dArhgef10 e investigar a base celular subjacente ao defeito no alinhamento dos cardioblastos observado nos mutantes. Os nossos resultados revelaram que a deleção de darhgef10 provoca uma severa redução da viabilidade, sem no entanto comprometer o tempo de desenvolvimento e a longevidade. Por outro lado, o aumento da expressão de darhgef10 em músculos, glândulas salivares e no disco imaginal do olho afeta drasticamente a integridade destes tecidos. A expressão ectópica de darhgef10 in vitro e in vivo revelou que a proteína está localiza no citoplasma com enriquecimento junto à membrana celular, com associação à actina F. Live imaging de embriões mutantes para darhgef10 revelou que os defeitos observados no coração podem estar associados a um defeito na adesão dos músculos alary e/ou das células pericardiais ao vaso dorsal. O homólogo humano de darhgef10, ARHGEF10, também é expresso no coração e está associação a uma maior susceptibilidade para a ocorrência de acidentes vasculares cerebrais aterotrombóticos, sugerindo que o que aprendemos sobre darhgef10 em Drosophila pode ter implicações do ponto de vista clínico para a saúde humana. ----------------------------- ABSTRACT: Mutations in genes controlling heart development and abnormalities in any of its steps frequently cause cardiac malformations, the most common type of birth defects in humans, affecting nearly 1% of births per year. Hence around 20 million adults are expected to live with a congenital heart defect. The Drosophila melanogaster heart, called dorsal vessel, is a relatively simple organ that acts as a muscular pump contracting automatically to allow the circulation of hemolymph. Drosophila heart formation shares many similarities with heart development in vertebrates providing a powerful system to study gene networks and regulatory pathways involved in heart development. We have previously identified a Drosophila gene, darhgef10, which is strongly expressed in the developing heart and when deleted, leads to flies with highly prevalent yet subtle heart abnormalities, compatible with unchallenged life in the laboratory. Our aims were to phenotypically characterize homozygous null darhgef10 mutants, characterize the subcellular localization of dArhgef10 and to study the cellular basis of the misaligned cardioblasts defect. We found that about half of darhgef10 mutants die during development. However, the survivors surprisingly have a nearly normal developmental time, adult locomotor behavior and total lifespan. Detection of transgene-derived dArhgef10 protein in vitro and in vivo using custom antibodies revealed a cytosolic protein slightly enriched in the cellular membranes and associated with F-actin. Tissue-specific darhgef10 expression disrupts the normal morphology of developing muscles, salivary glands and the eye. Live imaging of darhgef10 mutant embryos revealed that heart defect could be caused by a reduced capacity of attachment of pericardial cells and/or alary muscle to dorsal vessel. The human homolog of darhgef10 is also expressed in the heart and is a susceptibility gene for atherothrombotic stroke, suggesting that what we learn about the function of this gene and its phenotypes in Drosophila could have implications to human health.

Human-Human Collaboration in Virtual Teams

Extended and networked enterprises distribute the design of products, planning of the production process, and manufacturing regionally if not globally. Employees are therefore confronted with collaborative work over remote sites. A cost effective collaboration depends highly on the organization maintaining a common understanding for this kind of work and a suitable support with information and communication technology. The usual face to face work is going to be replaced at least partly if not totally by computer mediated collaboration. Creating and maintaining virtual teams is a challenge to work conditions as well as technology. New developments on cost-effective connections are providing not only vision and auditory perception but also haptic perception. Research results for improving remote collaboration are presented. Individual, social and cultural aspects are considered as new requirements on the employees of networked and extended enterprises.

Human-robot teamwork: a knowledge-based solution

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

Reactivity of human fetal and adult immortalized hepatocytes to potentially toxic bilirubin and bile acid species

Dissertação apresentada para a obtenção do Grau de Mestre em Genética Molecular e Biomedicina, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

How human schematization and systematic errors take effect on sketch map formalizations

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

The influence of geometric factors on the wall shear stress distribution in realistic human coronary arteries

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Biomédica. A presente dissertação foi desenvolvida no Erasmus Medical Center em Roterdão, Holanda

Human and climatic change impact modelling on the habitat suitability for the chimpanzee (Pan troglodytes ellioti) – Case study: The proposed Mount Cameroon National Park

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

Póst-Human: corpos e identidades, os novos objectos do

Pensar o ordenamento do território – ideias, planos, estratégias, Lisboa, UNL-FCSH-IPHI, (110,117).

Characterization of the glycosylation of human tumor cells

Ovarian cancer is within the most lethal gynecological malignancies in woman. Therefore, many investigators study its biological aspects with the purpose of discovering more rapid diagnostic methods and efficient treatment. Resembling many other tumors, in ovarian cancer, aberrant glycosylation occurs with the appearance of novel or altered carbohydrate structures. These can be terminal motifs, such as the Lewis determinants, or entire carbohydrate sequences, which have been related to tumorigenesis and its outcome.(...)

Enterprise information portals: potential for evaluating research for knowledge management and human capital assets using social network analysis

Paper presented at the ECKM 2010 – 11th European Conference on Knowledge Management, 2-3 September, 2010, Famalicão, Portugal. URL: http://www.academic-conferences.org/eckm/eckm2010/eckm10-home.htm

Is ambient intelligence a truly human-centric paradigm in industry? Current research and application scenario

Based on the paper presented at the International Conference “Autonomous Systems: inter-relations of technical and societal issues”, organized by IET with the support of the Portuguese-German collaboration project on “Technology Assessment of Autonomous Robotics” (DAAD/CRUP) at FCT-UNL, Biblioteca da UNL, Campus de Caparica on 5-6 November 2009.

Preventing human trafficking for the purpose of sexual exploitation: the need for a bottom-up approach : the case-study of Brazilians trafficked to Portugal

Masters Thesis – Academic Year 2007/2008 - European Master’s Degree in Human Rights and Democratization (E.MA) - European Inter-university Centre for Human Rights and Democratization (EIUC) -Faculdade de Direito, Universidade Nova de Lisboa (UNL)

Fast-to-fed shift in glucose homeostasis: clues to an earlier detection of human prediabetic states

FCM: UC Bioquímica I - PhD Thesis

Microencapsulation technology: a powerful tool for human embryonic stem cells expansion and cryopreservation

Dissertation presented to obtain a Master degree in Biotechnology at the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

New analytical methodologies for doping control – detection of anabolic androgenic steroids in human urine

Dissertation submitted to Faculdade de Ciências e Tecnologia - Universidade Nova de Lisboa in fulfilment of the requirements for the degree of Doctor of Philosophy (Biochemistry - Biotechnology)