Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus

Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses

As transformações do trabalho e desafios teórico-metodológicos da Ergonomia Transformations of work and theoretical-methodological challenges of ergonomics

O artigo enfoca a evolução do trabalho identificando as mudanças ocorridas e como elas transformaram a sua natureza. Ele apresenta o desenvolvimento teórico das abordagens utilizadas na relação do homem com o trabalho conseqüente à introdução de inovações tecnológicas. O enfoque adotado neste texto privilegia a análise das situações de trabalho informatizadas e como elas impactam nas condições de trabalho. O referencial norteador é a Ergonomia, seus modelos de intervenção e seus limites, neste novo contexto de trabalho.<br>The article contextualizes the evolution of work, identifying the changes occurred and how they have transformed the nature of work. It presents the theoretical development of the approaches used in the relationship between man and work in consequence of the technological innovations. The approach adopted in this text favors the analysis of computerized work situations and how they impact on the work conditions. The leading reference is Ergonomics, its intervention models and its limits in this new work context