783 research outputs found

    Autophagy is activated and involved in cell death with participation of cathepsins during stress-induced microspore embryogenesis in barley

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    Microspores are reprogrammed towards embryogenesis by stress. Many microspores die after this stress, limiting the efficiency of microspore embryogenesis. Autophagy is a degradation pathway that plays critical roles in stress response and cell death. In animals, cathepsins have an integral role in autophagy by degrading autophagic material; less is known in plants. Plant cathepsins are papain-like C1A cysteine proteases involved in many physiological processes, including programmed cell death. We have analysed the involvement of autophagy in cell death, in relation to cathepsin activation, during stress-induced microspore embryogenesis in Hordeum vulgare. After stress, reactive oxygen species (ROS) and cell death increased and autophagy was activated, including HvATG5 and HvATG6 up-regulation and increase of ATG5, ATG8, and autophagosomes. Concomitantly, cathepsin L/F-, B-, and H-like activities were induced, cathepsin-like genes HvPap-1 and HvPap-6 were up-regulated, and HvPap-1, HvPap-6, and HvPap-19 proteins increased and localized in the cytoplasm, resembling autophagy structures. Inhibitors of autophagy and cysteine proteases reduced cell death and promoted embryogenesis. The findings reveal a role for autophagy in stress-induced cell death during microspore embryogenesis, and the participation of cathepsins. Similar patterns of activation, expression, and localization suggest a possible connection between cathepsins and autophagy. The results open up new possibilities to enhance microspore embryogenesis efficiency with autophagy and/or cysteine protease modulators.España, MINECO AGL2014-52028-R and AGL2017-82447-

    Solitary-wave vortices in quadratic nonlinear media

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    We find families of vortex solitary waves in bulk quadratic nonlinear media under conditions for second-harmonic generation. We show that the vortex solitary waves are azimuthally unstable and that they decay into sets of stable spatial solitons. We calculate the growth rates of the azimuthal perturbations and show how those affect the pattern of output light. © 1998 Optical Society of AmericaPeer ReviewedPostprint (published version

    Phosphorus Availability Regulates TORC1 Signaling via LST8 in Chlamydomonas

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    Target of rapamycin complex 1 (TORC1) is a central regulator of cell growth. It balances anabolic and catabolic processes in response to nutrients, growth factors, and energy availability. Nitrogen- and carbon-containing metabolites have been shown to activate TORC1 in yeast, animals, and plants. Here, we show that phosphorus (P) regulates TORC1 signaling in the model green alga Chlamydomonas (Chlamydomonas reinhardtii) via LST8, a conserved TORC1 subunit that interacts with the kinase domain of TOR. P starvation results in a sharp decrease in LST8 abundance and downregulation of TORC1 activity. A hypomorphic lst8 mutation resulted in decreased LST8 abundance, and it both reduced TORC1 signaling and altered the cellular response to P starvation. Additionally, we found that LST8 levels and TORC1 activity were not properly regulated in a mutant defective in the transcription factor PSR1, which is the major mediator of P deprivation responses in Chlamydomonas. Unlike wild-type cells, the psr1 mutant failed to downregulate LST8 abundance and TORC1 activity when under P limitation. These results identify PSR1 as an upstream regulator of TORC1 and demonstrate that TORC1 is a key component in P signaling in Chlamydomonas.España Ministerio de Economía y Competitividad (grants BFU2015-68216-P and PGC2018-099048- B-100 to J.L.C. and grant BIO2015-74432-JIN to M.E.P.-P.)National Science Foundation (CAREER award MCB-1552522 to L.M.H. and grant MCB-1616820 to J.G.U.)European Commission (grant number 750996

    The educational e-portfolio: preliminary evidence of its relationship with student\u2019s self-efficacy and engagement

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    The educational use of portfolios has been increasing in the last few years, especially as technology has also developed electronic versions of portfolios. Although there is abundant information about their benefits and practice description, few studies provide empirical evidence of their implementation. The objective of this study was to provide initial evidence about the use of the portfolio in higher education. Concretely, we aimed 1) to explore the correlation between students’ performance on the portfolio and their performance on more traditional assessment methods 2) to explore whether student’s personal variables predict performance in key elements of the e-portfolio, such as individual reflections, and if these contribute to general academic performance in the course, and 3) to evaluate whether the use of the e-portfolio during a semester changes the students’ self-efficacy and engagement. For this purpose, an initial sample of 73 students were recruited, and an e-portfolio (based on Mahara) was implemented over a semester. The results showed that performance on the portfolio correlated with the score obtained on multiple choice tests. There was an increase in self-efficacy after one semester of e-portfolio implementation, and engagement proved to be an important predictor of the final course grade through the mediation of individual reflections. These results offer preliminary and promising evidence about the relationship of a specific element of e-portfolios, individual reflections with several variables related to academic achievement such as self-efficacy and engagement

    Papel de los equipos de atención primaria en la hospitalización infantil de los niños menores de 2 años

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    ObjetivoDeterminar si la conformación de los equipos de atención primaria con la realización del programa de salud del niño sano da lugar a una disminución del riesgo de hospitalización en los niños menores de 2 años, respecto al sistema sanitario tradicional de consultorio o ambulatorio.DiseñoEstudio epidemiológico de casos-referencia.Casos40% de los niños hospitalizados menores de 24 meses en plantas de hospitalización pediátricas o neonatal del Hospital Universitario Marqués de Valdecilla.Referencia15% de los recién nacidos vivos en dicho hospital. Recogida de información mediante entrevista personal y consulta de la tarjeta sanitaria.Período de estudioabril de 1995 a mayo de 1996.ResultadosLos niños menores de 2 años controlados habitualmente por un médico perteneciente a un equipo de atención primaria presentan una disminución del riesgo de hospitalización para todos los diagnósticos clínicos de 0,57 (IC del 95%, 0,35–0,93), tras haber ajustado por diferentes factores de confusión como educación materna, clase social, etnia, edad materna, consumo de tabaco materno, lactancia natural al nacimiento, ingreso al nacimiento. Se observó una disminución del riesgo de hospitalización por fiebre sin localización aparente en aquellos niños controlados habitualmente por un médico de equipo (RR ajustado, 0,41; IC del 95%, 0,19–0,90).ConclusiónLas ventajas de la reforma en la asistencia sanitaria en el ámbito pediátrico, con la conformación de los equipos de atención primaria y la realización de las actividades que ello conlleva, se traduce en una disminución del riesgo de hospitalización para aquellos niños menores de 2 años cuyo control habitual es realizado por un pediatra perteneciente a un equipo de atención primaria.ObjectiveTo determine whether the structure of primary care teams on carrying out the healthy child health programme leads to a drop in the risk of admission to hospital of children under two, in comparison with the traditional clinic or out-clinic health system.DesignCase-reference epidemiological study.Cases40% of the children under 24 months admitted to paediatric or neonate floors of the Marqués de Valdecilla University Hospital.Reference15% of the recently born children alive in this hospital. Information was gathered through face-to-face interview and by examining health cards. The study ran from April 1995 to May 1996.ResultsChildren under two monitored habitually by a doctor belonging to a primary care team showed a drop in risk of hospital admission for all clinical diagnoses of 0.57 (95% CI, 0.35–0.93), after adjustment due to various confusion factors such as maternal education, social class, ethnic background, mother's age, mother's tobacco consumption, natural breast-feeding at birth, admission at birth. There was a drop of risk of hospital admission for high temperature without apparent cause in those children monitored habitually by a team doctor (adjusted RR = 0.41; 95% CI, 0.19–0.90).ConclusionsThe advantages of the paediatric health care reform with the structuring of the primary care teams and the accompanying activities performed lead to a drop in the risk of hospital admission of those children under two years old who are habitually monitored by a doctor belonging to a primary care team

    Pharmacological glossary

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    Este glosario ha sido confeccionado fundamentalmente para ser trabajado por estudiantes que tienen que ver con el Inglés para propósitos médicos. Este compila la mayoría de los medicamentos utilizados en e tratamiento de algunas enfermedades, con el tratamiento médico para cada enfermedad, lo cual aparece en el libro "Medicina Práctica", utilizado en el 4to año de la carrera médica. Los medicamentos compilados se clasifican en diferentes grupos de acuerdo con sus funciones. Se trata de utilizar en clases como material complementario para proveer a los estudiantes con algunos términos farmacológicos necesarios para ellos como futuros profesionales, pero también puede ser utilizado por todos los profesionales interesados en el tema. Este trabajo es sólo el comienzo de lo que podemos hacer en este campo. Recomendamos su uso en todas las carreras médicas así como en cursos especializados

    Donnan Dialysis for Recovering Ammonium from Fermentation Solutions Rich in Volatile Fatty Acids

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    Funding Information: Universitat Politècnica de València and Ministerio de Universidades de España (Plan de Recuperación, Transformación y Resiliencia—financed by European Union—Next GenerationEU) are acknowledged for the post-doctoral research grant attributed to Kayo Santana Barros. Funding Information: This work was financed by Fundação para a Ciência e a Tecnologia, I.P., Lisbon, Portugal in the scope of the projects UIDP/04378/2020, UIDB/04378/2020 and PTDC/BTA-BTA/30902/2017 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. The work was also supported through the projects UIDB/50006/2020 and UIDP/50006/2020, funded by FCT/MCTES through national funds. Publisher Copyright: © 2023 by the authors.For the production of polyhydroxyalkanoates (PHA) using nitrogen-rich feedstocks (e.g., protein-rich resources), the typical strategy of restricting cell growth as a means to enhance overall PHA productivity by nitrogen limitation is not applicable. In this case, a possible alternative to remove the nitrogen excess (NH4+/NH3) is by applying membrane separation processes. In the present study, the use of Donnan dialysis to separate ammonium ions from volatile fatty acids present in the media for the production of PHA was evaluated. Synthetic and real feed solutions were used, applying NaCl and HCl receiver solutions separated by commercial cation-exchange membranes. For this specific purpose, Fumasep and Ralex membranes showed better performance than Ionsep. Sorption of ammonium ions occurred in the Ralex membrane, thus intensifying the ammonium extraction. The separation performances with NaCl and HCl as receiver solutions were similar, despite sorption occurring in the Ralex membrane more intensely in the presence of NaCl. Higher volumetric flow rates, NaCl receiver concentrations, and volume ratios of feed:receiver solutions enhanced the degree of ammonium recovery. The application of an external electric potential difference to the two-compartment system did not significantly enhance the rate of ammonium appearance in the receiver solution. The results obtained using a real ammonium-containing solution after fermentation of cheese whey showed that Donnan dialysis can be successfully applied for ammonium recovery from such solutions.publishersversionpublishe

    Efecto alelopático de especies invasoras de ribera sobre la germinación de especies del sotobosque

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    9 páginas. -- Trabajo presentado en la 50ª Reunión Científica de la SEEPLa producción de sustancias alelopáticas por las especies vegetales contribuye a incrementar su éxito competitivo frente a otras especies coexistentes dentro de un mismo hábitat, pudiendo llegar incluso a eliminarlas. Las sustancias alelopáticas pueden inhibir la germinación y el crecimiento de otras especies de la comunidad. En los bosques de ribera se ha detectado la presencia de árboles exóticos con potencial invasor en otros ecosistemas pero se desconoce su efecto sobre las especies autóctonas herbáceas. Nuestra hipótesis es que las especies invasoras podrían utilizar la producción de aleloquímicos de una manera eficiente para desplazar a las especies herbáceas autóctonas, pudiendo llegar a eliminarlas. El objetivo del presente trabajo fue estudiar el efecto extractos de hojarasca de especies alóctonas arbóreas (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) y autóctonas (Populus alba) sobre la germinación de cuatro especies herbáceas frecuentes en el sotobosque del bosque de ribera del rio Henares (Madrid). Los resultados mostraron una disminución de la velocidad de germinación de B. phoenicoides y B. sylvaticum con los extractos de las especies alóctonas y autóctonas excepto para el olmo siberiano. Chenopodium album no se vio perjudicada por los extractos de las especies alóctonas pero sí por lo de la especie autóctona. La velocidad de germinación de Dactylis glomerata fue afectada por los extractos de todas las especies alóctonas. Se concluye que no existe un efecto consistente de los extractos de las hojas de árboles exóticos sobre las herbáceas nativas, sino que éstos dependen tanto de la naturaleza del árbol donante como de la herbácea receptora.Plants produce allelopathic substances increasing their competitive success over other species coexisting within the same habitat, being able to eliminate them. Allelopathic substances inhibit germination and growth of other species in the community. In the riverside forests, it has been detected, the presence of invasive tree species with demonstrated invasive potential in other ecosystems. Our hypothesis is that invasive species could use the production of allelochemicals in an efficient way to compete against native herbaceous species. The aim of this work was to assess the effects of leaf extracts of invasive species (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) and native (Populus alba) on the germination of four grass species frequent in the forest understory bank of the river Henares (Madrid). The results showed that extracts of alien and native species (except Siberian elm) decreased the germination speed of B. phoenicoides and B. sylvaticum. The effect of extracts in Chenopodium album was not clear. The extracts of all alien species affected the germination speed of Dactylis glomerata.Agradecemos la ayuda de la Dra. Teodora Martínez en la localización de las zonas de campo. Este trabajo ha sido financiado por los proyectos POII10-0179-4700 de la Junta de Castilla La Mancha y CGL2010-16388/BOS del Ministerio de Ciencia e Innovación.Peer reviewe
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