66 research outputs found

    DNA methylation in ciliates: implications in differentiation processes

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    Much experimental evidence on the role of DNA methylation in gene expression has been reported. Here we review reports on DNA methylation in ciliated protozoa, emphasizing its implications in cell differentiation processes. Both types of methylated bases (adenine and cytosine) can be found in macronuclear DNA. The division cycle and conjugation have been studied with regard to adenine methylation, and several different functions have been assigned to the methylation changes detected in these processes. Cytosine methylation changes were analyzed during stomatogenesis of Paramecium and encystment of Colpoda inflata. A comparative analysis with other similar microbial eukaryotic differentiation processes is carried out

    Processing of Agilent microRNA array data

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    <p>Abstract</p> <p>Background</p> <p>The Agilent microRNA microarray platform interrogates each microRNA with several copies of distinct oligonucleotide probes and integrates the results into a total gene signal (TGS), using a proprietary algorithm that makes use of the background subtracted signal. The TGS can be normalized between arrays, and the Agilent recommendation is either not to normalize or to normalize to the 75<sup>th </sup>percentile signal intensity. The <it>robust multiarray average algorithm </it>(RMA) is an alternative method, originally developed to obtain a summary measure of mRNA Affymetrix gene expression arrays by using a linear model that takes into account the probe affinity effect. The RMA method has been shown to improve the accuracy and precision of expression measurements relative to other competing methods. There is also evidence that it might be preferable to use non-corrected signals for the processing of microRNA data, rather than background-corrected signals. In this study we assess the use of the RMA method to obtain a summarized microRNA signal for the Agilent arrays.</p> <p>Findings</p> <p>We have adapted the RMA method to obtain a processed signal for the Agilent arrays and have compared the RMA summarized signal to the TGS generated with the image analysis software provided by the vendor. We also compared the use of the RMA algorithm with uncorrected and background-corrected signals, and compared quantile normalization with the normalization method recommended by the vendor. The pre-processing methods were compared in terms of their ability to reduce the variability (increase precision) of the signals between biological replicates. Application of the RMA method to non-background corrected signals produced more precise signals than either the RMA-background-corrected signal or the quantile-normalized Agilent TGS. The Agilent TGS normalized to the 75% percentile showed more variation than the other measures.</p> <p>Conclusions</p> <p>Used without background correction, a summarized signal that takes into account the probe effect might provide a more precise estimate of microRNA expression. The variability of quantile normalization was lower compared with the normalization method recommended by the vendor.</p

    Prototipo de dos sistemas de atrapanieblas como un recurso hídrico y alternativa de abastecimiento a un invernadero para fortalecer la educación ambiental en la comunidad educativa del colegio Ofelia Uribe de Acosta en Yomasa- Usme

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    Practica socialLa falta de recursos socioeconómicos que presenta la localidad de Usme muestra la necesidad de generar un recurso hídrico para la comunidad educativa, el cual se presentó a través de una estructura de captación de agua donde se genere un impacto ambiental y social en los estudiantes el cual mejore sus índices de calidad de vida he instaure procesos de reciclaje escolar.1. INTRODUCCIÓN 2. PLANTEAMIENTO Y FORMULACION DEL PROBLEMA 3. ANTECEDENTES Y JUSTIFICACION 4. PLANTEAMIENTO Y FORMUALCION DE LA PREGUNTA 5. OBJETIVOS 6. ESTADO DEL ARTE 7.MARCO TEORICO 8. MARCO CONCEPTUAL 9. METODOLOGIA 10.PRESUPUESTO DEL TRABAJO Y FUENTES DE FINANCIACION 11. ALCANCE Y LIMITACIONES 12. RESULTADOS ANALISIS Y PRODUCTOS 13. CONCLUSIONES 14. SUGERENCIAS 15 ANEXO REFERENCIASPregradoIngeniero Civi

    Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon

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    Supplementary Data are available at NAR OnlineThe human immunodeficiency virus type 1 (HIV-1) regulator Tat is essential for viral replication because it achieves complete elongation of viral transcripts. Tat can be released to the extracellular space and taken up by adjacent cells, exerting profound cytoskeleton rearrangements that lead to apoptosis. In contrast, intracellular Tat has been described as protector from apoptosis. Tat gene is composed by two coding exons that yield a protein of 101 amino acids (aa). First exon (1–72aa) is sufficient for viral transcript elongation and second exon (73–101 aa) appears to contribute to non-transcriptional functions. We observed that Jurkat cells stably expressing intracellular Tat101 showed gene expression deregulation 4-fold higher than cells expressing Tat72. Functional experiments were performed to evaluate the effect of this deregulation. First, NF-iB-, NF-AT- and Sp1-dependent transcriptional activities were greatly enhanced in Jurkat-Tat101, whereas Tat72 induced milder but efficient activation. Second, cytoskeleton-related functions as cell morphology, proliferation, chemotaxis, polarization and actin polymerization were deeply altered in Jurkat- Tat101, but not in Jurkat-Tat72. Finally, expression of several cell surface receptors was dramatically impaired by intracellular Tat101 but not by Tat72. Consequently, these modifications were greatly dependent on Tat second exon and they could be related to the anergy observed in HIV-1-infected T cells.Plan Nacional del SIDA (MVI 1434/05–5), FIPSE 36584/ 06 and 36633/07, VIRHORST Network from Comunidad de Madrid (Spain), FIS PI040614 and PI0808752, ISCIII-RETIC RD06/0006, EUROPRISE Network of Excellence of the EU (Grant no. LSHP CT-2006- 037611), and BIO2008-04384 from the Ministerio de Ciencia e Innovacio´ n, Espan˜ a. Funding for open access charge: Instituto de Salud Carlos III, Ministry of Science and Technology, Spain.Peer reviewe

    Early peroxisome proliferator-activated receptor gamma regulated genes involved in expansion of pancreatic beta cell mass.

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    BACKGROUND: The progression towards type 2 diabetes depends on the allostatic response of pancreatic beta cells to synthesise and secrete enough insulin to compensate for insulin resistance. The endocrine pancreas is a plastic tissue able to expand or regress in response to the requirements imposed by physiological and pathophysiological states associated to insulin resistance such as pregnancy, obesity or ageing, but the mechanisms mediating beta cell mass expansion in these scenarios are not well defined. We have recently shown that ob/ob mice with genetic ablation of PPARγ2, a mouse model known as the POKO mouse failed to expand its beta cell mass. This phenotype contrasted with the appropriate expansion of the beta cell mass observed in their obese littermate ob/ob mice. Thus, comparison of these models islets particularly at early ages could provide some new insights on early PPARγ dependent transcriptional responses involved in the process of beta cell mass expansion RESULTS: Here we have investigated PPARγ dependent transcriptional responses occurring during the early stages of beta cell adaptation to insulin resistance in wild type, ob/ob, PPARγ2 KO and POKO mice. We have identified genes known to regulate both the rate of proliferation and the survival signals of beta cells. Moreover we have also identified new pathways induced in ob/ob islets that remained unchanged in POKO islets, suggesting an important role for PPARγ in maintenance/activation of mechanisms essential for the continued function of the beta cell. CONCLUSIONS: Our data suggest that the expansion of beta cell mass observed in ob/ob islets is associated with the activation of an immune response that fails to occur in POKO islets. We have also indentified other PPARγ dependent differentially regulated pathways including cholesterol biosynthesis, apoptosis through TGF-β signaling and decreased oxidative phosphorylation.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Modeling the intervention scheme of the type of change for Colombia. An empirical application of the quantile regression under neuronal networks

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    RESUMEN: En este artículo se determina la eficiencia de las intervenciones realizadas por el Banco de la República empleando el modelo teórico de canal de coordinación. En este modelo, el efecto que tiene un diferencial de tasas de interés, la variable de intervenciones construida por medio de un modelo Markov-switching y el proceder de los inversionistas técnicos y fundamentalistas sobre diferentes cuantiles del retorno de la tasa representativa del mercado (TRM) son evaluados. Usando una función de impulso respuesta, se encontró que la variable intervenciones genera el mayor impacto en el retorno de la TRM en los cuantiles del 5 % y 25 %, pero sin alcanzarse una reversión media completa en el cuantil del 50 %ABSTRACT: This article evaluates the efficiency of Banco de la Republica’s interventions using a coordination channel theoretical model. In this model, the effect of the differential interest rate, an intervention variable derived using a Markov-switching model, and the actions of technical and fundamentalists investors on the quantiles of return of the exchange rate (TRM for its initials in Spanish) are evaluated. By using an impulse-response function it was found that the intervention variable has a high effect on the TRM returns in the fifth and twenty-fifth quantiles, but without obtaining a complete mean reversion on the fiftieth quantile

    Modelando el esquema de intervenciones del tipo de cambio para colombia. una aplicación empírica de la técnica de regresión del cuantil bajo redes neuronales

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    En este artículo se determina la eficiencia de las intervenciones realizadas por el Banco de la República empleando el modelo teórico de canal de coordinación. En este modelo, el efecto que tiene un diferencial de tasas de interés, la variable de intervenciones construida por medio de un modelo Markov-switching y el proceder de los inversionistas técnicos y fundamentalistas sobre diferentes cuantiles del retorno de la tasa representativa del mercado (TRM) son evaluados. Usando una función de impulso respuesta, se encontró que la variable intervenciones genera el mayor impacto en el retorno de la TRM en los cuantiles del 5 % y 25 %, pero sin alcanzarse una reversión media completa en el cuantil del 50 %

    Long-Term Dabigatran Treatment Delays Alzheimer's Disease Pathogenesis in the TgCRND8 Mouse Model

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    BACKGROUND: Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder with important vascular and hemostatic alterations that should be taken into account during diagnosis and treatment. OBJECTIVES: This study evaluates whether anticoagulation with dabigatran, a clinically approved oral direct thrombin inhibitor with a low risk of intracerebral hemorrhage, ameliorates AD pathogenesis in a transgenic mouse model of AD. METHODS: TgCRND8 AD mice and their wild-type littermates were treated for 1 year with dabigatran etexilate or placebo. Cognition was evaluated using the Barnes maze, and cerebral perfusion was examined by arterial spin labeling. At the molecular level, Western blot and histochemical analyses were performed to analyze fibrin content, amyloid burden, neuroinflammatory activity, and blood-brain barrier (BBB) integrity. RESULTS: Anticoagulation with dabigatran prevented memory decline, cerebral hypoperfusion, and toxic fibrin deposition in the AD mouse brain. In addition, long-term dabigatran treatment significantly reduced the extent of amyloid plaques, oligomers, phagocytic microglia, and infiltrated T cells by 23.7%, 51.8%, 31.3%, and 32.2%, respectively. Dabigatran anticoagulation also prevented AD-related astrogliosis and pericyte alterations, and maintained expression of the water channel aquaporin-4 at astrocytic perivascular endfeet of the BBB. CONCLUSIONS: Long-term anticoagulation with dabigatran inhibited thrombin and the formation of occlusive thrombi in AD; preserved cognition, cerebral perfusion, and BBB function; and ameliorated neuroinflammation and amyloid deposition in AD mice. Our results open a field for future investigation on whether the use of direct oral anticoagulants might be of therapeutic value in AD.This work was funded by a Proof-of-Concept Award from the Robertson Therapeutic Development Fund (Dr. Cortes-Canteli), The Rockefeller University; NINDS/NIH grant NIS106668 (Drs. Norris and Strickland); European Union’s Seventh Framework Programme (FP7-PEOPLE-2013-IIF), grant agreement n PIIF-GA-2013-624811 (Drs. Cortes-Canteli and Fuster), CNIC, Madrid, Spain; Miguel Servet type I research contract (CP16/00174 and MS16/00174 [Dr. Cortes-Canteli]), Instituto de Salud Carlos III (ISCIII), CNIC; Iniciativa de Empleo Juvenil (PEJ16/MED/TL-1231 [A. Marcos-Diaz] and PEJ-2018-AI/BMD-11477 [C. Ceron]) from Consejería de Educación, Juventud y Deporte de la Comunidad de Madrid; European Regional Development Funds (FEDER “Una manera de hacer Europa”) and European Social Funds (FSE “El FSE invierte en tu futuro”); and with the support of the Marie Curie Alumni Association (Dr. Cortes-Canteli). The CNIC is supported by the ISCIII, the Spanish Ministerio de Ciencia, Innovación y Universidades (MCNU), and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). CIC biomaGUNE is a Maria de Maeztu Unit of Excellence (MDM-2017-0720). Dr. Sanchez-Gonzalez is an employee of Philips Healthcare. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.S

    In vivo expansion of a CD9+ decidual-like NK cell subset following autologous hematopoietic stem cell transplantation.

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    Autologous hematopoietic stem cell transplantation (autoHSCT) is a treatment option for hematological disorders and pediatric solid tumors. After an autoHSCT, natural killer (NK) cells are the first lymphocyte subset returning to normal levels. To uncover global changes during NK cell reconstitution after autoHSCT, we performed RNA-sequencing on NK cells before and after autoHSCT. Results showed profound changes in the gene expression profile of NK cells immediately after autoHSCT. Several biological processes including cell cycle, DNA replication and the mevalonate pathway were enriched. Significantly, we observed that following autoHSCT, NK cells acquired a decidual-like gene expression profile, including the expression of CD9. By using multiparametric flow cytometry, we confirmed the expansion of NK cells expressing CD9 immediately after autoHSCT, which exhibited higher granzyme B and perforin expression levels than CD9- NK cells. These results provide insights into the physiopathology of NK cells during their reconstitution after autoHSCT.Supported by the following grants: AECC-Spanish Association Against Cancer (PROYE16074- BORR) and Health Department, Basque Government (2021333006). GA-P is the recipient of a predoctoral contract funded by AECC-Spanish Association Against Cancer (PRDVZ21440ASTA). DP-A is a recipient of a fellowship from the AECC-Spanish Association Against Cancer (PPLAB212164POLA), AA-I and GA-P are recipient of a fellowship from the Jesús de Gangoiti Barrera Foundation (FJGB20/007, FJGB21/001 and FJBG21/005). IT is recipient of a predoctoral contract funded by the Department of Education, Basque Government (PRE_2021_2_0215). OZ is the recipient of a postdoctoral contract funded by ‘‘Instituto de Salud Carlos III-Contratos Sara Borrell 2017 (CD17/00128)’’ and the European Social Fund (ESF)-The ESF invests in your future. FB is an Ikerbasque Research Professor, Ikerbasque, Basque Foundation for Science.S
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