139 research outputs found

    Actividades de crianças do pré-escolar e educadores de infância com o computador em portugal

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    Muito se tem escrito hoje sobre a integração das tecnologias de informação e comunicação (TIC) na escola e diversas pesquisas têm vindo a demonstrar a importância da familiarização da criança desta idade com a tecnologia, quer porque esta faz parte inquestionável do mundo que a rodeia, quer pela relevância educativa das experiências que lhe pode proporcionar. No entanto existem muito poucos estudos que nos descrevam e analisem processos efectivos de integração da tecnologia na Escola em geral, e ao nível da educação Pré-Escolar em particular. Este foi o ponto de partida da nossa investigação, verificar as práticas de crianças e Educadores de Infância com as TIC, mais especificamente o computador, em Portugal. Elaborámos um questionário que foi enviado, via correio electrónico, para Educadores de Infância de todo o país e como forma de triangulação de dados foram realizadas observações em dois jardins-de-infância, mais concretamente nas aulas de informática das crianças do pré-escolar. Terminamos com conclusões baseadas nos dados recolhidos e algumas considerações finais sobre o tema

    Identification and characterization of Tc1/mariner-like DNA transposons in genomes of the pathogenic fungi of the Paracoccidioides species complex

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    <p>Abstract</p> <p>Background</p> <p><it>Paracoccidioides brasiliensis </it>(Eukaryota, Fungi, Ascomycota) is a thermodimorphic fungus, the etiological agent of paracoccidioidomycosis, the most important systemic mycoses in Latin America. Three isolates corresponding to distinct phylogenetic lineages of the <it>Paracoccidioides </it>species complex had their genomes sequenced. In this study the identification and characterization of class II transposable elements in the genomes of these fungi was carried out.</p> <p>Results</p> <p>A genomic survey for DNA transposons in the sequence assemblies of <it>Paracoccidioides</it>, a genus recently proposed to encompass species <it>P. brasiliensis </it>(harboring phylogenetic lineages S1, PS2, PS3) and <it>P. lutzii </it>(<it>Pb01-like </it>isolates), has been completed. Eight new <it>Tc1/mariner </it>families, referred to as Trem (<b>Tr</b>ansposable <b>e</b>lement <b>m</b>ariner), labeled A through H were identified. Elements from each family have 65-80% sequence similarity with other <it>Tc1/mariner </it>elements. They are flanked by 2-bp TA target site duplications and different termini. Encoded DDD-transposases, some of which have complete ORFs, indicated that they could be functionally active. The distribution of Trem elements varied between the genomic sequences characterized as belonging to <it>P. brasiliensis </it>(S1 and PS2) and <it>P. lutzii</it>. TremC and H elements would have been present in a hypothetical ancestor common to <it>P. brasiliensis </it>and <it>P. lutzii</it>, while TremA, B and F elements were either acquired by <it>P. brasiliensis </it>or lost by <it>P. lutzii </it>after speciation. Although TremD and TremE share about 70% similarity, they are specific to <it>P. brasiliensis </it>and <it>P. lutzii</it>, respectively. This suggests that these elements could either have been present in a hypothetical common ancestor and have evolved divergently after the split between <it>P. brasiliensis </it>and <it>P. Lutzii</it>, or have been independently acquired by horizontal transfer.</p> <p>Conclusions</p> <p>New families of <it>Tc1/mariner </it>DNA transposons in the genomic assemblies of the <it>Paracoccidioides </it>species complex are described. Families were distinguished based on significant BLAST identities between transposases and/or TIRs. The expansion of Trem in a putative ancestor common to the species <it>P. brasiliensis </it>and <it>P. lutzii </it>would have given origin to TremC and TremH, while other elements could have been acquired or lost after speciation had occurred. The results may contribute to our understanding of the organization and architecture of genomes in the genus <it>Paracoccidioides</it>.</p

    A Paracoccidioides brasiliensis glycan shares serologic and functional properties with cryptococcal glucuronoxylomannan

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    The cell wall of the yeast form of the dimorphic fungus Paracoccidioides brasiliensis is enriched with alpha 1,3-glucans. in Cryptococcus neoformans, alpha 1,3-glucans interact with glucuronoxylomannan (GXM), a hetero-polysaccharide that is essential for fungal virulence. in this study, we investigated the occurrence of P. brasiliensis glycans sharing properties with cryptococcal GXM. Protein database searches in P. brasiliensis revealed the presence of sequences homologous to those coding for enzymes involved in the synthesis of GXM and capsular architecture in C. neoformans. in addition, monoclonal antibodies (mAbs) raised to cryptococcal GXM bound to P. brasiliensis cells. Using protocols that were previously established for extraction and analysis of C neoformans GXM, we recovered a P. brasiliensis glycan fraction composed of mannose and galactose, in addition to small amounts of glucose, xylose and rhamnose. in comparison with the C. neoformans GXM, the P. brasiliensis glycan fraction components had smaller molecular dimensions. the P. brasiliensis components, nevertheless, reacted with different GXM-binding mAbs. Extracellular vesicle fractions of P. brasiliensis also reacted with a GXM-binding mAb, suggesting that the polysaccharide-like molecule is exported to the extracellular space in secretory vesicles. An acapsular mutant of C. neoformans incorporated molecules from the P. brasiliensis extract onto the cell wall, resulting in the formation of surface networks that resembled the cryptococcal capsule. Coating the C. neoformans acapsular mutant with the P. brasiliensis glycan fraction resulted in protection against phagocytosis by murine macrophages. These results suggest that P. brasiliensis and C. neoformans share metabolic pathways required for the synthesis of similar polysaccharides and that P. brasiliensis yeast cell walls have molecules that mimic certain aspects of C. neoformans GXM. These findings are important because they provide additional evidence for the sharing of antigenically similar components across phylogenetically distant fungal species. Since GXM has been shown to be important for the pathogenesis of C neoformans and to elicit protective antibodies, the finding of similar molecules in P. brasiliensis raises the possibility that these glycans play similar functions in paracoccidiomycosis. (C) 2012 Elsevier Inc. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)NIHCenter for AIDS Research at EinsteinInterhemispheric Research Training Grant in Infectious Diseases, Fogarty International CenterDepartment of EnergyFiocruz MS, CDTS, BR-21040360 Rio de Janeiro, BrazilUniv Fed Rio de Janeiro, Inst Microbiol Prof Paulo de Goes, BR-21941902 Rio de Janeiro, BrazilAlbert Einstein Coll Med, Dept Microbiol & Immunol, Bronx, NY 10461 USAUniversidade Federal de São Paulo, Disciplina Biol Celular, BR-04023062 São Paulo, BrazilUniv Fed Rio de Janeiro, Inst Biofis Carlos Chagas Filho, Lab Ultraestrutura Celular Hertha Meyer, BR-21941903 Rio de Janeiro, BrazilAlbert Einstein Coll Med, Div Infect Dis, Dept Med, Bronx, NY 10461 USAUniversidade Federal de São Paulo, Disciplina Biol Celular, BR-04023062 São Paulo, BrazilNIH: AI033142NIH: AI033774NIH: AI052733NIH: HL059842Interhemispheric Research Training Grant in Infectious Diseases, Fogarty International Center: NIH D43-TW007129Department of Energy: DE-FG-9-93ER-20097Web of Scienc

    Gene Copy-Number Variation in Haploid and Diploid Strains of the Yeast Saccharomyces cerevisiae

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    The increasing ability to sequence and compare multiple individual genomes within a species has highlighted the fact that copy-number variation (CNV) is a substantial and underappreciated source of genetic diversity. Chromosome-scale mutations occur at rates orders of magnitude higher than base substitutions, yet our understanding of the mechanisms leading to CNVs has been lagging. We examined CNV in a region of chromosome 5 (chr5) in haploid and diploid strains of Saccharomyces cerevisiae. We optimized a CNV detection assay based on a reporter cassette containing the SFA1 and CUP1 genes that confer gene dosage-dependent tolerance to formaldehyde and copper, respectively. This optimized reporter allowed the selection of low-order gene amplification events, going from one copy to two copies in haploids and from two to three copies in diploids. In haploid strains, most events involved tandem segmental duplications mediated by nonallelic homologous recombination between flanking direct repeats, primarily Ty1 elements. In diploids, most events involved the formation of a recurrent nonreciprocal translocation between a chr5 Ty1 element and another Ty1 repeat on chr13. In addition to amplification events, a subset of clones displaying elevated resistance to formaldehyde had point mutations within the SFA1 coding sequence. These mutations were all dominant and are proposed to result in hyperactive forms of the formaldehyde dehydrogenase enzyme

    Omics Approaches for Understanding Biogenesis, Composition and Functions of Fungal Extracellular Vesicles

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    This is the final version. Available on open access from Frontiers Media via the DOI in this recordExtracellular vesicles (EVs) are lipid bilayer structures released by organisms from all kingdoms of life. The diverse biogenesis pathways of EVs result in a wide variety of physical properties and functions across different organisms. Fungal EVs were first described in 2007 and different omics approaches have been fundamental to understand their composition, biogenesis, and function. In this review, we discuss the role of omics in elucidating fungal EVs biology. Transcriptomics, proteomics, metabolomics, and lipidomics have each enabled the molecular characterization of fungal EVs, providing evidence that these structures serve a wide array of functions, ranging from key carriers of cell wall biosynthetic machinery to virulence factors. Omics in combination with genetic approaches have been instrumental in determining both biogenesis and cargo loading into EVs. We also discuss how omics technologies are being employed to elucidate the role of EVs in antifungal resistance, disease biomarkers, and their potential use as vaccines. Finally, we review recent advances in analytical technology and multi-omic integration tools, which will help to address key knowledge gaps in EVs biology and translate basic research information into urgently needed clinical applications such as diagnostics, and immuno- and chemotherapies to fungal infections.NIHPacific Northwest National Laboratory (PNNL)CNPq/Science Without Borders Science Program, BrazilJohns Hopkins Malaria Research InstituteFAPESPCAPESCNPqMedical Research Council (MRC

    Therapeutic DNA Vaccine Encoding Peptide P10 against Experimental Paracoccidioidomycosis

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    Paracoccidioidomycosis (PCM), caused by Paracoccidioides brasiliensis, is the most prevalent invasive fungal disease in South America. Systemic mycoses are the 10th most common cause of death among infectious diseases in Brazil and PCM is responsible for more than 50% of deaths due to fungal infections. PCM is typically treated with sulfonamides, amphotericin B or azoles, although complete eradication of the fungus may not occur and relapsing disease is frequently reported. A 15-mer peptide from the major diagnostic antigen gp43, named P10, can induce a strong T-CD4+ helper-1 immune response in mice. The TEPITOPE algorithm and experimental data have confirmed that most HLA-DR molecules can present P10, which suggests that P10 is a candidate antigen for a PCM vaccine. In the current work, the therapeutic efficacy of plasmid immunization with P10 and/or IL-12 inserts was tested in murine models of PCM. When given prior to or after infection with P. brasiliensis virulent Pb 18 isolate, plasmid-vaccination with P10 and/or IL-12 inserts successfully reduced the fungal burden in lungs of infected mice. In fact, intramuscular administration of a combination of plasmids expressing P10 and IL-12 given weekly for one month, followed by single injections every month for 3 months restored normal lung architecture and eradicated the fungus in mice that were infected one month prior to treatment. The data indicate that immunization with these plasmids is a powerful procedure for prevention and treatment of experimental PCM, with the perspective of being also effective in human patients
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