110 research outputs found

    Examining Signatures of Natural Selection in Antifungal Resistance Genes Across Aspergillus Fungi

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    Certain Aspergillus fungi cause aspergillosis, a set of diseases that typically affect immunocompromised individuals. Most cases of aspergillosis are caused by Aspergillus fumigatus, which infects millions of people annually. Some closely related so-called cryptic species, such as Aspergillus lentulus, can also cause aspergillosis, albeit at lower frequencies, and they are also clinically relevant. Few antifungal drugs are currently available for treating aspergillosis and there is increasing worldwide concern about the presence of antifungal drug resistance in Aspergillus species. Furthermore, isolates from both A. fumigatus and other Aspergillus pathogens exhibit substantial heterogeneity in their antifungal drug resistance profiles. To gain insights into the evolution of antifungal drug resistance genes in Aspergillus, we investigated signatures of positive selection in 41 genes known to be involved in drug resistance across 42 susceptible and resistant isolates from 12 Aspergillus section Fumigati species. Using codon-based site models of sequence evolution, we identified ten genes that contain 43 sites with signatures of ancient positive selection across our set of species. None of the sites that have experienced positive selection overlap with sites previously reported to be involved in drug resistance. These results identify sites that likely experienced ancient positive selection in Aspergillus genes involved in resistance to antifungal drugs and suggest that historical selective pressures on these genes likely differ from any current selective pressures imposed by antifungal drugs.RS was supported by the Brazilian São Paulo Research Foundation (FAPESP) grant numbers 2017/21983-3 and 2019/07526-4. JS and AR are supported by the Howard Hughes Medical Institute through the James H. Gilliam Fellowships for Advanced Study Program. AR’s laboratory received additional support from a Discovery grant from Vanderbilt University, the Burroughs Wellcome Fund, the National Science Foundation (DEB-1442113), and the National Institutes of Health/National Institute of Allergy and Infectious Diseases (R56AI146096). GHG was supported by FAPESP (2016/07870-9) and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq).S

    Amazonia as a carbon source linked to deforestation and climate change

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    Amazonia hosts the Earth's largest tropical forests and has been shown to be an important carbon sink over recent decades1-3. This carbon sink seems to be in decline, however, as a result of factors such as deforestation and climate change1-3. Here we investigate Amazonia's carbon budget and the main drivers responsible for its change into a carbon source. We performed 590 aircraft vertical profiling measurements of lower-tropospheric concentrations of carbon dioxide and carbon monoxide at four sites in Amazonia from 2010 to 20184. We find that total carbon emissions are greater in eastern Amazonia than in the western part, mostly as a result of spatial differences in carbon-monoxide-derived fire emissions. Southeastern Amazonia, in particular, acts as a net carbon source (total carbon flux minus fire emissions) to the atmosphere. Over the past 40 years, eastern Amazonia has been subjected to more deforestation, warming and moisture stress than the western part, especially during the dry season, with the southeast experiencing the strongest trends5-9. We explore the effect of climate change and deforestation trends on carbon emissions at our study sites, and find that the intensification of the dry season and an increase in deforestation seem to promote ecosystem stress, increase in fire occurrence, and higher carbon emissions in the eastern Amazon. This is in line with recent studies that indicate an increase in tree mortality and a reduction in photosynthesis as a result of climatic changes across Amazonia1,10.</p

    O modelo de gestão ecônomica (GECON) aplicado á área de produção

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    Para a realização deste estudo, observou-se duas realidades no cotidiano das empresas e na literatura específica das áreas de Administração, Economia e Contabilidade: 1. a competitividade estabelecida entre as empresas com a globalização dos mercados, a formação de blocos econômicos e a postura mais liberalizante das principais economias mundiais; 2. as informações contábeis geradas com a metodologia da Contabilidade tradicional não atendem satisfatoriamente aos gestores das empresas que, procurando adaptar-se à realidade de mercado extremamente competitivo, assumiram um novo paradigma de produção. Diante destes fatos, verifica-se, como premissa básica do estudo, que as empresas, ao adotarem em suas estratégias de negócios um posicionamento identificado com um novo paradigma de produção, necessitam de uma estruturação no Processo de Gestão compatível com esta opção. Com este enfoque, delineam-se, primeiramente, os conceitos do Modelo de Gestão Econômica - GECON, como uma proposta de suprir as necessidades de informações econômicas dos gestores, no processo decisório de suas áreas de responsabilidade. em seguida, discorre-se sobre a área de Produção, com características de uma unidade de negócio. A partir desta abordagem, é desenvolvido o Modelo GECON aplicado à área de Produção, que trata esta área como uma unidade administrativa independente, objetivando otimizar o seu resultado econômico com eficácia, para melhor contribuir para o resultado global da empresa e assegurar sua continuidade

    Amazonia as a carbon source linked to deforestation and climate change

    Get PDF
    Amazonia hosts the Earth’s largest tropical forests and has been shown to be an important carbon sink over recent decades1,2,3. This carbon sink seems to be in decline, however, as a result of factors such as deforestation and climate change1,2,3. Here we investigate Amazonia’s carbon budget and the main drivers responsible for its change into a carbon source. We performed 590 aircraft vertical profiling measurements of lower-tropospheric concentrations of carbon dioxide and carbon monoxide at four sites in Amazonia from 2010 to 20184. We find that total carbon emissions are greater in eastern Amazonia than in the western part, mostly as a result of spatial differences in carbon-monoxide-derived fire emissions. Southeastern Amazonia, in particular, acts as a net carbon source (total carbon flux minus fire emissions) to the atmosphere. Over the past 40 years, eastern Amazonia has been subjected to more deforestation, warming and moisture stress than the western part, especially during the dry season, with the southeast experiencing the strongest trends5,6,7,8,9. We explore the effect of climate change and deforestation trends on carbon emissions at our study sites, and find that the intensification of the dry season and an increase in deforestation seem to promote ecosystem stress, increase in fire occurrence, and higher carbon emissions in the eastern Amazon. This is in line with recent studies that indicate an increase in tree mortality and a reduction in photosynthesis as a result of climatic changes across Amazonia1,10

    Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis

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    The presence of intestinal helminths can down-regulate the immune response required to control mycobacterial infection. BALB/c mice infected with Mycobacterium bovis following an infection with the intestinal helminth Strongyloides venezuelensis showed reduced interleukin-17A production by lung cells and increased bacterial burden. Also, small granulomas and a high accumulation of cells expressing the inhibitory molecule CTLA-4 were observed in the lung. These data suggest that intestinal helminth infection could have a detrimental effect on the control of tuberculosis (TB) and render coinfected individuals more susceptible to the development of TB
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