56 research outputs found

    Apoptosis resistance in HIV-1 persistently-infected cells is independent of active viral replication and involves modulation of the apoptotic mitochondrial pathway

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    <p>Abstract</p> <p>Background</p> <p>HIV triggers the decline of CD4<sup>+ </sup>T cells and leads to progressive dysfunction of cell-mediated immunity. Although an increased susceptibility to cell death occurs during the acute phase of HIV infection, persistently-infected macrophages and quiescent T-cells seem to be resistant to cell death, representing a potential reservoir for virus production.</p> <p>Results</p> <p>Lymphoid (H9/HTLVIII<sub>B </sub>and J1.1) and pro-monocytic (U1) HIV-1 persistently-infected cell lines were treated with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and staurosporine (STS) for 24 h, and susceptibility to apoptosis was evaluated and compared with uninfected counterparts (H9, Jurkat and U937 respectively). When exposed to different pro-apoptotic stimuli, all persistently-infected cell lines showed a dramatic reduction in the frequency of apoptotic cells in comparison with uninfected cells. This effect was independent of the magnitude of viral replication, since the induction of viral production in lymphoid or pro-monocytic cells by exposure to TNF-α or PMA did not significantly change their susceptibility to H<sub>2</sub>O<sub>2</sub>- or STS-induced cell death. A mechanistic analysis revealed significant diferences in mitochondrial membrane potential (MMP) and caspase-3 activation between uninfected and persistently-infected cells. In addition, Western blot assays showed a dramatic reduction of the levels of pro-apototic Bax in mitochondria of persistently-infected cells treated with H<sub>2</sub>O<sub>2 </sub>or STS, but not in uninfected cells.</p> <p>Conclusion</p> <p>This study represents the first evidence showing that resistance to apoptosis in persistently-infected lymphoid and monocytic cells is independent of active viral production and involves modulation of the mitochondrial pathway. Understanding this effect is critical to specifically target the persistence of viral reservoirs, and provide insights for future therapeutic strategies in order to promote complete viral eradication.</p

    Detection of HIV-1 dual infections in highly exposed treated patients

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    <p>Abstract</p> <p>Background</p> <p>Genetic characterization of HIV-1 in Argentina has shown that BF recombinants predominate among heterosexuals and injecting drug users, while in men who have sex with men the most prevalent form is subtype B.</p> <p>Objectives</p> <p>The aim of this work was to investigate the presence of HIV dual infections in HIV-infected individuals with high probability of reinfection</p> <p>Study design</p> <p>Blood samples were collected from 23 HIV positive patients with the risk of reinfection from Buenos Aires. A fragment of the HIV gene <it>pol </it>was amplified and phylogenetic analyses were performed. Antiretroviral drug resistance patterns of all the sequences were analyzed.</p> <p>Results</p> <p>Five dual infections were detected with four patients coinfected with subtype B and BF recombinants and one patient was coinfected with two BF recombinants presenting different recombination patterns. Prolonged infection with a stable clinical condition was observed in the five individuals. Resistance mutation patterns were different between the predominant and the minority strains.</p> <p>Conclusions</p> <p>Our results show that HIV dual infection can occur with closely related subtypes, and even with different variants of the same recombinant form in certain populations. Clinical observations showed neither aggressive disease progression nor impact on the resistance patterns in the dually-infected patients.</p

    A review on viral metagenomics in extreme environments

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    Viruses are the most abundant biological entities in the biosphere, and have the ability to infect Bacteria, Archaea, and Eukaryotes. The virome is estimated to be at least ten times more abundant than the microbiome with 107 viruses per milliliter and 109 viral particles per gram in marine waters and sediments or soils, respectively. Viruses represent a largely unexplored genetic diversity, having an important role in the genomic plasticity of their hosts. Moreover, they also play a significant role in the dynamics of microbial populations. In recent years, metagenomic approaches have gained increasing popularity in the study of environmental viromes, offering the possibility of extending our knowledge related to both virus diversity and their functional characterization. Extreme environments represent an interesting source of both microbiota and their virome due to their particular physicochemical conditions, such as very high or very low temperatures and >1 atm hydrostatic pressures, among others. Despite the fact that some progress has been made in our understanding of the ecology of the microbiota in these habitats, few metagenomic studies have described the viromes present in extreme ecosystems. Thus, limited advances have been made in our understanding of the virus community structure in extremophilic ecosystems, as well as in their biotechnological potential. In this review, we critically analyze recent progress in metagenomic based approaches to explore the viromes in extreme environments and we discuss the potential for new discoveries, as well as methodological challenges and perspectives

    Planeación, gobernanza y sustentabilidad Retos y desafíos desde el enfoque territorial

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    Frente a la compleja realidad actual, resulta ineludible el desarrollo de la investigación científica de los fenómenos y procesos urbanos, territoriales y ambientales, que contribuya a su comprensión y la construcción de alternativas de solución a los retos y desafíos vigentes. En este contexto, el abordaje de las ciudades y regiones metropolitanas, el ordenamiento del territorio y la ocupación del espacio, así como la relación sociedad-naturaleza y la complejidad ambiental, precisa la generación de metodologías y procesos de investigación multi e inter disciplinarios que contribuyan a la comprensión de los procesos socioterritoriales, el mejoramiento de las condiciones de vida y la conservación ambiental.Programa de Fortalecimiento de la Calidad Educativa PFCE-2016 proyecto K0313101

    Conversaciones sobre el cambio social

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    “Una conversación abierta, cercana y pertinente, que nos invite a conocer los desafíos contemporáneos, a crear oportunidades sociales y a potenciar el conocimiento.” Gonzalo Pérez Rojas"Este libro recoge la experiencia de una conversación enriquecedora en el interior de una organización como Grupo Sura que se dio la oportunidad de enfrentar las preguntas coyunturales desde los fundamentos del cambio social. En lugar de detenerse en titulares de prensa o contenidos de redes sociales, tan virales como falaces, el grupo de conversadores emprendió un viaje por lugares e ideas diversas para poner en perspectiva asunto de interés común tales como la democracia, nuestra historia nacional y local, la justicia, el lenguaje, el derecho, el conflicto, entre otros ; de este modo, fue posible validar la vigencia de, por ejemplo, el pensamiento ateniense de veinticinco siglos atrás frente a los retos contemporáneos de las decisiones colectivas de las organizaciones. La Universidad EAFIT ha sido mediadora y testigo de este proceso que puede entenderse como catarsis, en el sentido de purga, purificación y transformación que la tragedia griega confiere. Dicho de otro modo, la conversación acerca de estos diferentes tópicos ético-políticos relevantes para la empresa fueron pretexto para plantear preguntas íntimas de los participantes y para encontrar criterios de conexión con las cuestiones sociales del retador contexto actual". Centro Humanista Universidad EAFIT© Universidad EAFIT- Centro Humanista, © Grupo Sur

    Experiencias en el aula: segundo encuentro de prácticas pedagógicas innovadoras

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    Experiencias de profesores en su quehacer en los distintos ambientes de aprendizaje presenciales y a distancia.La segunda entrega de Experiencias en el aula es una publicación anual que recoge las ponencias ganadoras presentadas en el Segundo Encuentro de Prácticas Pedagógicas Innovadoras, organizado por el Centro de Excelencia Docente aeiou, de la Vicerrectoría General Académica de la Corporación Universitaria Minuto de Dios – UNIMINUTO Todas las ponencias publicadas en la segunda entrega de Experiencias en el aula fueron seleccionadas por evaluadores externos durante la convocatoria al Segundo Encuentro de Prácticas Pedagógicas Innovadoras en el que fueron presentadas; este evento, organizado por el Centro de Excelencia Docente aeiou, y la Vicerrectoría General Académica de la Corporación Universitaria Minuto de Dios- UNIMINUTO, tuvo lugar los días 9 y 10 de octubre de 2017

    A communal catalogue reveals Earth’s multiscale microbial diversity

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    Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity
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