305 research outputs found

    Propuesta para la aplicación de un sistema de gestión ambiental basado en la Norma ISO 14001:2015 en la planta de tintorería de la fábrica Marsar SRL

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    A medida que la preocupación por los problemas medioambientales aumenta en la sociedad y se unen fuerzas para establecer medidas de control y protección para la mitigación de estos, consecuencia de los procesos productivos de las diversas industrias, el crecimiento demográfico y por acciones del ser humano, la visión de los organismos defensores de la sostenibilidad del medio están sobre las industrias, es por eso que se hace necesario la implementación de un sistema de gestión ambiental sostenible que establezca políticas y planes de acción alineados con la sostenibilidad y el mejoramiento continuo. Los motivos que con llevan a pensar en la implementación de este sistema es el desarrollo de la responsabilidad social y ética de la empresa, a las presiones ejercidas por los órganos defensores del medio ambiente y a la oportunidad de mejora de la competitividad y rentabilidad que ofrece. En la actualidad existen diversos sistemas de gestión sostenibles, pero los más conocidos son los que están basados en las normas ISO 14001, EMAS y EKOSCAN, son sistemas afines uno más exigente que otro pero que ayudan a estructurar, establecer políticas, planes y acciones enfocados a un desarrollo sostenible; la elección del sistema a implementar va a depender del tipo de organización, capacidades, situación y envergadura de la empresa. El optar por un tipo de sistema requiere del compromiso de la alta dirección, las capacitaciones de todo el personal y la evaluación ambiental del estado actual para proceder con la implementación.Trabajo de investigaciónCampus Lima Centr

    La imagen al servicio del texto: masora ornamental en el manuscrito bíblico hebreo BH Mss1

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    The Masoretic notes that appear alongside the biblical text written in geometric or figured shapes are little studied to date. The few existing studies usually focus on the form without paying attention to the content. The biblical Hebrew manuscript BH Mss1 (M1) has a huge number of Masoretic notes in figured patterns and while the existence of figured Masorah has been addressed, their designs have not been described and studied in relation to their content. This paper focuses on the figured Masorah notes, their location, shape and content. From a joint analysis of the form and content it is possible to conclude that the main purpose behind writing the Masorah in figured patterns in M1 is a practical one: to record all the information in the available space.Las noticias masoréticas escritas en formas geométricas o figurativas que aparecen junto al texto bíblico han sido poco estudiadas hasta la fecha. Los escasos estudios existentes se suelen centrar en la forma, sin tener en cuenta el contenido. El manuscrito bíblico BH Mss1 (M1) contiene un gran número de noticias masoréticas en forma figurativa que, si bien ya habían sido mencionadas, sus diseños no han sido descritos ni estudiados en relación con su contenido. El presente trabajo se centra en las noticias de Masora figurativa, su localización, forma y contenido. El análisis conjunto de la forma y el contenido de las noticias permite concluir que la razón principal para escribir la Masora en forma figurativa en M1 es práctica

    Se equivocó el masoreta ¿se equivocaba?

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    This article has a didactic purpose; it is not aimed at scholars of the Masora but rather at researchers in closely associated areas. The editions of Hebrew Biblical manuscripts and critical studies that have been published recently are particularly useful tools for those who wish to delve into other areas of research such as the history of the Hebrew Biblical text, its exegesis or the origins of grammar. Here, the author concentrates on the analysis of three issues: variant formulations of a same information; coherence between a text and its Masorah, and the possible discrepancies among sources.Este artículo, de carácter didáctico, no está destinado a los estudiosos de la Masora, sino a investigadores de áreas cercanas. Las ediciones de manuscritos y los estudios publicados en los últimos años son instrumentos de gran utilidad para quienes deseen adentrarse en un campo de investigación con repercusión en otras áreas tales como la historia del texto bíblico hebreo, su exégesis o los inicios de la gramática. Se analizan tres cuestiones: distinta formulación para una misma noticia, coherencia entre un texto y su masora y posibles discrepancias entre las fuentes

    Escherichia coli RNA polymerase-associated SWI/SNF protein RapA: evidence for RNA-directed binding and remodeling activity

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    Helicase-like SWI/SNF proteins are present in organisms belonging to distant kingdoms from bacteria to humans, indicating that they perform a very basic and ubiquitous form of nucleic acid management; current studies associate the activity of SWI/SNF proteins with remodeling of DNA and DNA–protein complexes. The bacterial SWI/SNF homolog RapA—an integral part of the Escherichia coli RNA polymerase complex—has been implicated in remodeling post-termination DNA–RNA polymerase–RNA ternary complexes (PTC), however its explicit nucleic acid substrates and mechanism remain elusive. Our work presents evidence indicating that RNA is a key substrate of RapA. Specifically, the formation of stable RapA–RNA intermediates in transcription and other, independent lines of evidence presented herein indicate that RapA binds and remodels RNA during transcription. Our results are consistent with RapA promoting RNA release from DNA–RNA polymerase–RNA ternary complexes; this process may be accompanied by the destabilization of non-canonical DNA–RNA complexes (putative DNA–RNA triplexes). Taken together, our data indicate a novel RNA remodeling activity for RapA, a representative of the SWI/SNF protein superfamily

    Fine Tuning of Globin Gene Expression by DNA Methylation

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    Expression patterns in the globin gene cluster are subject to developmental regulation in vivo. While the γ(A) and γ(G) genes are expressed in fetal liver, both are silenced in adult erythrocytes. In order to decipher the role of DNA methylation in this process, we generated a YAC transgenic mouse system that allowed us to control γ(A) methylation during development. DNA methylation causes a 20-fold repression of γ(A) both in non-erythroid and adult erythroid cells. In erythroid cells this modification works as a dominant mechanism to repress γ gene expression, probably through changes in histone acetylation that prevent the binding of erythroid transcription factors to the promoter. These studies demonstrate that DNA methylation serves as an elegant in vivo fine-tuning device for selecting appropriate genes in the globin locus. In addition, our findings provide a mechanism for understanding the high levels of γ-globin transcription seen in patients with Hereditary Persistence of Fetal Hemoglobin, and help explain why 5azaC and butyrate compounds stimulate γ-globin expression in patients with β-hemoglobinopathies

    Imprinted CDKN1C Is a Tumor Suppressor in Rhabdoid Tumor and Activated by Restoration of SMARCB1 and Histone Deacetylase Inhibitors

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    SMARCB1 is deleted in rhabdoid tumor, an aggressive paediatric malignancy affecting the kidney and CNS. We hypothesized that the oncogenic pathway in rhabdoid tumors involved epigenetic silencing of key cell cycle regulators as a consequence of altered chromatin-remodelling, attributable to loss of SMARCB1, and that this hypothesis if proven could provide a biological rationale for testing epigenetic therapies in this disease. We used an inducible expression system to show that the imprinted cell cycle inhibitor CDKN1C is a downstream target for SMARCB1 and is transcriptionally activated by increased histone H3 and H4 acetylation at the promoter. We also show that CDKN1C expression induces cell cycle arrest, CDKN1C knockdown with siRNA is associated with increased proliferation, and is able to compete against the anti-proliferative effect of restored SMARCB1 expression. The histone deacetylase inhibitor (HDACi), Romidepsin, specifically restored CDKN1C expression in rhabdoid tumor cells through promoter histone H3 and H4 acetylation, recapitulating the effect of SMARCB1 on CDKNIC allelic expression, and induced cell cycle arrest in G401 and STM91-01 rhabdoid tumor cell lines. CDKN1C expression was also shown to be generally absent in clinical specimens of rhabdoid tumor, however CDKN1A and CDKN1B expression persisted. Our observations suggest that maintenance of CDKN1C expression plays a critical role in preventing rhabdoid tumor growth. Significantly, we report for the first time, parallels between the molecular pathways of SMARCB1 restoration and Romidepsin treatment, and demonstrate a biological basis for the further exploration of histone deacetylase inhibitors as relevant therapeutic reagents in the treatment of rhabdoid tumor

    Human SWI/SNF directs sequence-specific chromatin changes on promoter polynucleosomes

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    Studies in humans and other species have revealed that a surprisingly large fraction of nucleosomes adopt specific positions on promoters, and that these positions appear to be determined by nucleosome positioning DNA sequences (NPSs). Recent studies by our lab, using minicircles containing only one nucleosome, indicated that the human SWI/SNF complex (hSWI/SNF) prefers to relocate nucleosomes away from NPSs. We now make use of novel mapping techniques to examine the hSWI/SNF sequence preference for nucleosome movement in the context of polynucleosomal chromatin, where adjacent nucleosomes can limit movement and where hSWI/SNF forms altered dinucleosomal structures. Using two NPS templates (5S rDNA and 601) and two hSWI/SNF target promoter templates (c-myc and UGT1A1), we observed hSWI/SNF-driven depletion of normal mononucleosomes from almost all positions that were strongly favored by assembly. In some cases, these mononucleosomes were moved to hSWI/SNF-preferred sequences. In the majority of other cases, one repositioned mononucleosome appeared to combine with an unmoved mononucleosome forming a specifically localized altered or normal dinucleosome. These effects result in dramatic, template-specific changes in nucleosomal distribution. Taken together, these studies indicate hSWI/SNF is likely to activate or repress transcription of its target genes by generating promoter sequence-specific changes in chromatin configuration

    ARID1B is a specific vulnerability in ARID1A-mutant cancers

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    Summary Recent studies have revealed that ARID1A is frequently mutated across a wide variety of human cancers and also has bona fide tumor suppressor properties. Consequently, identification of vulnerabilities conferred by ARID1A mutation would have major relevance for human cancer. Here, using a broad screening approach, we identify ARID1B, a related but mutually exclusive homolog of ARID1A in the SWI/SNF chromatin remodeling complex, as the number one gene preferentially required for the survival of ARID1A-mutant cancer cell lines. We show that loss of ARID1B in ARID1A-deficient backgrounds destabilizes SWI/SNF and impairs proliferation. Intriguingly, we also find that ARID1A and ARID1B are frequently co-mutated in cancer, but that ARID1A-deficient cancers retain at least one ARID1B allele. These results suggest that loss of ARID1A and ARID1B alleles cooperatively promotes cancer formation but also results in a unique functional dependence. The results further identify ARID1B as a potential therapeutic target for ARID1A-mutant cancers
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