2,470 research outputs found

    Vascular Endothelial Growth Factor (VEGF) Prevents the Downregulation of the Cholinergic Phenotype in Axotomized Motoneurons of the Adult Rat

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    Vascular endothelial growth factor (VEGF) was initially characterized by its activity on the vascular system. However, there is growing evidence indicating that VEGF also acts as a neuroprotective factor, and that its administration to neurons suffering from trauma or disease is able to rescue them from cell death. We questioned whether VEGF could also maintain damaged neurons in a neurotransmissive mode by evaluating the synthesis of their neurotransmitter, and whether its action would be direct or through its well-known angiogenic activity. Adult rat extraocular motoneurons were chosen as the experimental model. Lesion was performed by monocular enucleation and immediately a gelatine sponge soaked in VEGF was implanted intraorbitally. After 7 days, abducens, trochlear, and oculomotor nuclei were examined by immunohistochemistry against choline acetyltransferase (ChAT), the biosynthetic enzyme of the motoneuronal neurotransmitter acetylcholine. Lesioned motoneurons exhibited a noticeable ChAT downregulation which was prevented by VEGF administration. To explore whether this action was mediated via an increase in blood vessels or in their permeability, we performed immunohistochemistry against laminin, glucose transporter-1 and the plasmatic protein albumin. The quantification of the immunolabeling intensity against these three proteins showed no significant differences between VEGF-treated, axotomized and control animals. Therefore, the present data indicate that VEGF is able to sustain the cholinergic phenotype in damaged motoneurons, which is a first step for adequate neuromuscular neurotransmission, and that this action seems to be mediated directly on neurons since no sign of angiogenic activity was evident. These data reinforces the therapeutical potential of VEGF in motoneuronal diseases.España, MINECO and FEDER BFU2015-64515-PJunta de Andalucía and FEDER : P10-CVI605

    Indicadores de desempeño ambiental en la Facultad de Enfermería Arides Estevez Sánchez

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    Introducción: Para las instituciones de Educación Superior pertenecientes al sector de la salud, es una necesidad evaluar su desempeño ambiental e identificar avances y retrocesos en su relación con el medio ambiente. De ahí la importancia de contar con indicadores que faciliten la evaluación del desempeño ambiental en aras de lograr resultados positivos en la gestión ambiental de la institución. Objetivo: Definir indicadores para evaluar el desempeño ambiental en instituciones de Educación Superior de la Salud. Método: Se sustenta en una investigación estructurada en tres etapas: una exploratoria, otra confirmatoria y una última valorativa, conjugándose la metodología cualitativa y cuantitativa a través del empleo de métodos teóricos, empíricos y estadísticos, como son: la revisión bibliográfica, el criterio de especialistas, el análisis de clúster y el método de Proceso de Análisis jerárquico AHP. Resultados: Se obtuvieron 15 indicadores de evaluación de desempeño ambiental que están en correspondencia con los indicadores clasificados por la Norma ISO 14031. Estos fueron validados estadísticamente a través de un proceso de selección y análisis jerárquico. Conclusiones: Los indicadores seleccionados constituyen la garantía de contar con herramientas eficientes y apropiadas, con un reconocimiento mayoritario marcando las pautas para una buena evaluación del desempeño ambiental en la Facultad de Enfermería Arides Estevez Sánchez de Holguín. Palabras clave: Desempeño ambiental, indicadores, medio ambiente

    The eukaryote-specific N-terminal extension of ribosomal protein S31 contributes to the assembly and function of 40S ribosomal subunits

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    The archaea-/eukaryote-specific 40S-ribosomal-subunit protein S31 is expressed as an ubiquitin fusion protein in eukaryotes and consists of a conserved body and a eukaryote-specific N-terminal extension. In yeast, S31 is a practically essential protein, which is required for cytoplasmic 20S pre-rRNA maturation. Here, we have studied the role of the N-terminal extension of the yeast S31 protein. We show that deletion of this extension partially impairs cell growth and 40S subunit biogenesis and confers hypersensitivity to aminoglycoside antibiotics. Moreover, the extension harbours a nuclear localization signal that promotes active nuclear import of S31, which associates with pre-ribosomal particles in the nucleus. In the absence of the extension, truncated S31 inefficiently assembles into pre-40S particles and two subpopulations of mature small subunits, one lacking and another one containing truncated S31, can be identified. Plasmid-driven overexpression of truncated S31 partially suppresses the growth and ribosome biogenesis defects but, conversely, slightly enhances the hypersensitivity to aminoglycosides. Altogether, these results indicate that the N- terminal extension facilitates the assembly of S31 into pre-40S particles and contributes to the optimal translational activity of mature 40S subunits but has only a minor role in cytoplasmic cleavage of 20S pre-rRNA at site D

    The C-terminal tail of ribosomal protein Rps15 is engaged in cytoplasmic pre-40S maturation

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    The small ribosomal subunit protein Rps15/uS19 is involved in early nucleolar ribosome biogenesis and subsequent nuclear export of pre-40S particles to the cytoplasm. In addition, the C-terminal tail of Rps15 was suggested to play a role in mature ribosomes, namely during translation elongation. Here, we show that Rps15 not only functions in nucleolar ribosome assembly but also in cytoplasmic pre-40S maturation, which is indicated by a strong genetic interaction between Rps15 and the 40S assembly factor Ltv1. Specifically, mutations either in the globular or C-terminal domain of Rps15 when combined with the non-essential ltv1 null allele are lethal or display a strong growth defect. However, not only rps15 ltv1 double mutants but also single rps15 C-terminal deletion mutants exhibit an accumulation of the 20S pre-rRNA in the cytoplasm, indicative of a cytoplasmic pre-40S maturation defect. Since in pre-40S particles, the C-terminal tail of Rps15 is positioned between assembly factors Rio2 and Tsr1, we further tested whether Tsr1 is genetically linked to Rps15, which indeed could be demonstrated. Thus, the integrity of the Rps15 C-terminal tail plays an important role during late pre-40S maturation, perhaps in a quality control step to ensure that only 40S ribosomal subunits with functional Rps15 C-terminal tail can efficiently enter translation. As mutations in the C-terminal tail of human RPS15 have been observed in connection with chronic lymphocytic leukaemia, it is possible that apart from defects in translation, an impaired late pre-40S maturation step in the cytoplasm could also be a reason for this disease.Austrian science fund (FWF) P27996- B21, P28874-B21Ministerio de Ciencia e Innovación PID2019–103850-GB-I00Agencia Estatal de Investigación AEI/10.13039/ 501100011033Junta de Andalucía P20_00581, BIO-27

    SU(1,1) Coherent States For Position-Dependent Mass Singular Oscillators

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    The Schroedinger equation for position-dependent mass singular oscillators is solved by means of the factorization method and point transformations. These systems share their spectrum with the conventional singular oscillator. Ladder operators are constructed to close the su(1,1) Lie algebra and the involved point transformations are shown to preserve the structure of the Barut-Girardello and Perelomov coherent states.Comment: 11 pages, 5 figures. This shortened version (includes new references) has been adapted for its publication in International Journal of Theoretical Physic

    Energy Test of an Efficient Random Laser Emission Collecting System

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    The problem of light collection in random lasers (RLs) is addressed. As the radiation emitted by this system is Lambertian due to its spatial incoherence, a device based on an ellipsoidal revolution mirror is designed, developed, and tested in order to optimize the harvesting of the radiation emitted by the RL. The system provides a simple injection procedure of the emitted energy at the entrance of a multimode optical fiber. The results obtained show that the device has a net energy efficiency of 35%, close to the theoretically expected one. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported LicenseThis work was supported by the Basque Government PIBA2018-24, Spanish Government MINECO under Project No. MAT2017-87035-C2-2-P (AEI/FEDER, UE), and Basque Country University (UPV/EHU) PPG17/07 and GIU17/01

    Ubiquitin release from eL40 is required for cytoplasmic maturation and function of 60S ribosomal subunits in Saccharomyces cerevisiae

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    Ubiquitin is generated by proteolytic cleavage of precursor proteins in which it is fused either to itself, constituting a linear polyubiquitin protein of head‐to‐tail monomers, or as a single N‐terminal moiety to one of two ribosomal proteins, eL40 (Ubi1/2 precursors) and eS31 (Ubi3 precursor). It has been proposed that the ubiquitin moiety fused to these ribosomal proteins could act as a chaperone by facilitating their efficient production, folding and ribosome assembly in Saccharomyces cerevisiae. We have previously shown that ubiquitin release from eS31 is required for yeast viability and that noncleaved Ubi3 can get incorporated into translation‐competent 40S subunits. In this study, we have analysed the effects of mutations that partially or totally impair cleavage of the ubiquitin‐eL40A fusion protein. While noncleaved Ubi1 is not able to support growth when it is the sole cellular source of eL40, it can assemble into nascent pre‐60S particles. However, Ubi1‐containing 60S ribosomal subunits are not competent for translation. This is likely due to a steric interference of the unprocessed ubiquitin with the binding and function of factors that interact with the ribosome's GTPase‐associated centre. In agreement with this suggestion, Ubi1‐containing ribosomes affect the efficient recycling of the anti‐association factor Tif6 and have a reduced presence of translation elongation factors. We conclude that the removal of the ubiquitin moiety from ribosomal protein eL40 is an essential prerequisite for both the cytoplasmic maturation and the functionality of 60S ribosomal subunits

    Formación basada en competencias: experiencias en la Universidad de Holguín – Cuba

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    Los procesos de formación de los profesionales orientados al desarrollo de competencias, emergen para hacer de la educación un servicio más pertinente a las demandas sociales, es por ello que en el programa de maestría de Gestión Ambiental se adoptó este enfoque. El estudio mostró que el programa favoreció la incorporación de competencias en los egresados, quienes abordaron problemas objetivos de los diferentes contextos laborales, con un importante impacto socio-ambiental, además contribuyó a mejorar los indicadores ambientales en organizaciones del territorio y se aportaron herramientas teórico - metodológicas para mejorar el proceso de gestión ambiental

    The ubiquitin moiety of ubi1 is required for productive expression of ribosomal protein el40 in saccharomyces cerevisiae

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    Ubiquitin is a highly conserved small eukaryotic protein. It is generated by proteolytic cleavage of precursor proteins in which it is fused either to itself, constituting a polyubiquitin precursor of head-to-tail monomers, or as a single N-terminal moiety to ribosomal proteins. Understanding the role of the ubiquitin fused to ribosomal proteins becomes relevant, as these proteins are practically invariably eS31 and eL40 in the different eukaryotes. Herein, we used the amenable yeast Saccharomyces cerevisiae to study whether ubiquitin facilitates the expression of the fused eL40 (Ubi1 and Ubi2 precursors) and eS31 (Ubi3 precursor) ribosomal proteins. We have analyzed the phenotypic effects of a genomic ubi1∆ub-HA ubi2∆ mutant, which expresses a ubiquitin-free HA-tagged eL40A protein as the sole source of cellular eL40. This mutant shows a severe slow-growth phenotype, which could be fully suppressed by increased dosage of the ubi1∆ub-HA allele, or partially by the replacement of ubiquitin by the ubiquitin-like Smt3 protein. While expression levels of eL40A-HA from ubi1∆ub- HA are low, eL40A is produced practically at normal levels from the Smt3-S-eL40A- HA precursor. Finally, we observed enhanced aggregation of eS31-HA when derived from a Ubi3∆ub-HA precursor and reduced aggregation of eL40A-HA when expressed from a Smt3-S-eL40A-HA precursor. We conclude that ubiquitin might serve as a cis- acting molecular chaperone that assists in the folding and synthesis of the fused eL40 and eS31 ribosomal proteins

    Random Laser Action in Nd:YAG Crystal Powder Jon

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    This work explores the room temperature random stimulated emission at 1.064 mu m of a Nd:YAG crystal powder (Neodymium-doped yttrium aluminum garnet) in a very simple pump configuration with no assistance from an internal mirror. The laser threshold energy as a function of pump beam area and pump wavelength has been measured, as well as the temporal dynamics of emission pulses. The absolute energy of stimulated emission and the absolute laser slope efficiency have been measured by using a method proposed by the authors. The results show a surprising high efficiency that takes the low Nd3+ ion concentration of the crystal powder into account.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad, MINECO project MAT2013-48246-C2-2-P, the Basque Country Government, project IT-943-16, and Saiotek S-PE11UN072 and S-PC13UN017
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