Improved growth and morphological plasticity of <i>Haloferax volcanii</i>.

Some microbes display pleomorphism, showing variable cell shapes in a single culture, whereas others differentiate to adapt to changed environmental conditions. The pleomorphic archaeon Haloferax volcanii commonly forms discoid-shaped ('plate') cells in culture, but may also be present as rods, and can develop into motile rods in soft agar, or longer filaments in certain biofilms. Here we report improvement of H. volcanii growth in both semi-defined and complex media by supplementing with eight trace element micronutrients. With these supplemented media, transient development of plate cells into uniformly shaped rods was clearly observed during the early log phase of growth; cells then reverted to plates for the late log and stationary phases. In media prepared with high-purity water and reagents, without supplemental trace elements, rods and other complex elongated morphologies ('pleomorphic rods') were observed at all growth stages of the culture; the highly elongated cells sometimes displayed a substantial tubule at one or less frequently both poles, as well as unusual tapered and highly curved forms. Polar tubules were observed forming by initial mid-cell narrowing or tubulation, causing a dumbbell-like shape, followed by cell division towards one end. Formation of the uniform early log-phase rods, as well as the pleomorphic rods and tubules were dependent on the function of the tubulin-like cytoskeletal protein, CetZ1. Our results reveal the remarkable morphological plasticity of H. volcanii cells in response to multiple culture conditions, and should facilitate the use of this species in further studies of archaeal biology

Mycobacterial infection-induced miR-206 inhibits protective neutrophil recruitment via the CXCL12/CXCR4 signalling axis

Pathogenic mycobacteria actively dysregulate protective host immune signalling pathways during infection to drive the formation of permissive granuloma microenvironments. Dynamic regulation of host microRNA (miRNA) expression is a conserved feature of mycobacterial infections across host-pathogen pairings. Here we examine the role of miR-206 in the zebrafish model of Mycobacterium marinum infection, which allows investigation of the early stages of granuloma formation. We find miR-206 is upregulated following infection by pathogenic M. marinum and that antagomir-mediated knockdown of miR-206 is protective against infection. We observed striking upregulation of cxcl12a and cxcr4b in infected miR-206 knockdown zebrafish embryos and live imaging revealed enhanced recruitment of neutrophils to sites of infection. We used CRISPR/Cas9-mediated knockdown of cxcl12a and cxcr4b expression and AMD3100 inhibition of Cxcr4 to show that the enhanced neutrophil response and reduced bacterial burden caused by miR-206 knockdown was dependent on the Cxcl12/Cxcr4 signalling axis. Together, our data illustrate a pathway through which pathogenic mycobacteria induce host miR-206 expression to suppress Cxcl12/Cxcr4 signalling and prevent protective neutrophil recruitment to granulomas

Semantic Web-based Software Product Line for Building Intelligent Tutoring Systems

Intelligent Tutoring Systems (ITS) have been assumed as an important learning resource to be added as a module in e-learning systems. However, the construction of such systems is still a hard and complex task that involves, for instance, representation and manipulation of different knowledge source. To alleviate these issues, this paper proposes a new approach for building ITS by integrating Software Product Line and Semantic Web technologies focusing on two software engineering aspects: large-scale production and customization for different learners, and how to allow these knowledge to be automatically shared between software and authors in both reuse and knowledge evolution points of view. This paper shows a modeling for the proposed product line, as well as how the Semantic Web technologies was used to achieve the effective shared knowledge

Um Sistema para Inspeções de Garantia da Qualidade Baseado em Ontologias e Agentes

A implementação de práticas de garantia da qualidade possui uma relação custo/benefício difícil de balancear. Isso ocorre  porque o custo de execução das práticas é direto, enquanto que, o benefício obtido com estas é indireto. No intuito demelhorar essa relação, este trabalho apresenta um sistema de suporte para as inspeções de garantia da qualidade capaz de automatizar a definição de escopo e o endereçamento de não conformidades, além de gerenciar cadastros e calcular indicadores. O sistema é formado por uma ontologia, a qual mapeia a semântica envolvida nas inspeções de garantia da qualidade; e por agentes de software, os quais implementamas regras necessárias para automação das atividades mencionadas. Os experimentos realizados em uma Fábrica de Software mostraram melhora na produtividade nas inspeções, maximizando a cobertura, sem impactar no esforço demandado

Computação Desplugada: Um Mapeamento Sistemático da Literatura Nacional

Diante da eminente necessidade de ensinar Ciência da Computação no ensino básico e das dificuldades enfrentadas no seu processo de ensino e aprendizagem, nos últimos anos uma série de estudos têm usado uma estratégia conhecida por Computação Desplugada. No entanto, diversos questionamentos têm sido feitos, por exemplo: i) em quais níveis de ensino a Computação Desplugada tem sido trabalhada?; ii) quais atividades de Computação Desplugada têm sido implementadas?; e iii) como as pesquisas em Computação Desplugada têm sido avaliadas? No intuito de responder essas questões, esse artigo apresenta os resultados de um Mapeamento Sistemático da Literatura sobre Computação Desplugada no Brasil. Os principais resultados indicam que a maioria das abordagens baseiam-se nas atividades do livro “Computer Science Unplugged” e se concentram entre os níveis de ensino fundamental e médio, bem como, ´e notável a falta de estudos estatísticos sobre a Computação Desplugada no âmbito nacional

Ontology-based feature modeling: an empirical study in changing scenarios

A software product line (SPL) is a set of software systems that have a particular set of common features\ud and that satisfy the needs of a particular market segment or mission. Feature modeling is one of the key\ud activities involved in the design of SPLs. The feature diagram produced in this activity captures the commonalities\ud and variabilities of SPLs. In some complex domains (e.g., ubiquitous computing, autonomic\ud systems and context-aware computing), it is difficult to foresee all functionalities and variabilities a\ud specific SPL may require. Thus, Dynamic Software Product Lines (DSPLs) bind variation points at runtime\ud to adapt to fluctuations in user needs as well as to adapt to changes in the environment. In this context,\ud relying on formal representations of feature models is important to allow them to be automatically analyzed\ud during system execution. Among the mechanisms used for representing and analyzing feature\ud models, description logic (DL) based approaches demand to be better investigated in DSPLs since it provides\ud capabilities, such as automated inconsistency detection, reasoning efficiency, scalability and\ud expressivity. Ontology is the most common way to represent feature models knowledge based on DL reasoners.\ud Previous works conceived ontologies for feature modeling either based on OWL classes and properties\ud or based on OWL individuals. However, considering change or evolution scenarios of feature\ud models, we need to compare whether a class-based or an individual-based feature modeling style is\ud recommended to describe feature models to support SPLs, and especially its capabilities to deal with\ud changes in feature models, as required by DSPLs. In this paper, we conduct a controlled experiment to\ud empirically compare two approaches based on each one of these modeling styles in several changing scenarios\ud (e.g., add/remove mandatory feature, add/remove optional feature and so on). We measure time to\ud perform changes, structural impact of changes (flexibility) and correctness for performing changes in our\ud experiment. Our results indicate that using OWL individuals requires less time to change and is more\ud flexible than using OWL classes and properties. These results provide insightful assumptions towards\ud the definition of an approach relying on reasoning capabilities of ontologies that can effectively support\ud products reconfiguration in the context of DSPL.CNPqCAPE