1,165 research outputs found

    Freezing induces an increase in leaf spectral transmittance of forest understorey and alpine forbs

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    Evergreen plants growing at high latitudes or high elevations may experience freezing events in their photosynthetic tissues. Freezing events can have physical and physiological effects on the leaves which alter leaf optical properties affecting remote and proximal sensing parameters. We froze leaves of six alpine plant species (Soldanella alpina, Ranunculus kuepferi, Luzula nutans, Gentiana acaulis, Geum montanum, and Centaurea uniflora) and three evergreen forest understorey species (Hepatica nobilis, Fragaria vesca and Oxalis acetosella), and assessed their spectral transmittance and optically measured pigments, as well as photochemical efficiency of photosystem II (PSII) as an indicator of freezing damage. Upon freezing, leaves of all the species transmitted more photosynthetically active radiation (PAR) and some species had increased ultraviolet-A (UV-A) transmittance. These differences were less pronounced in alpine than in understorey species, which may be related to higher chlorophyll degradation, visible as reduced leaf chlorophyll content upon freezing in the latter species. Among these understorey forbs, the thin leaves of O. acetosella displayed the largest reduction in chlorophyll (−79%). This study provides insights into how freezing changes the leaf optical properties of wild plants which could be used to set a baseline for upscaling optical reflectance data from remote sensing. Changes in leaf transmittance may also serve to indicate photosynthetic sufficiency and physiological tolerance of freezing events, but experimental research is required to establish this functional association.Peer reviewe

    Alpine forbs rely on different photoprotective strategies during spring snowmelt

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    Snowmelt in alpine ecosystems brings ample water, and together with above-freezing temperatures, initiates plant growth. In this scenario, rapid activation of photosynthesis is essential for a successful life-history strategy. But, strong solar radiation in late spring enhances the risk of photodamage, particularly before photosynthesis is fully functional. We compared the photoprotective strategy of five alpine forbs: one geophyte not particularly specialised in subnival life (Crocus albiflorus) and four wintergreens differing in their degree of adaptation to subnival life, from least to most specialised: Gentiana acaulis, Geum montanum, Homogyne alpina and Soldanella alpina. We used distance to the edge of snow patches as a proxy to study time-dependent changes after melting. We postulated that the photoprotective response of snowbed specialists would be stronger than of more-generalist alpine meadow species. F-v/F-m was relatively low across wintergreens and even lower in the geophyte C. albiflorus. This species also had the largest xanthophyll-cycle pool and lowest tocopherol and flavonoid glycoside contents. After snow melting, all the species progressively activated ETR, but particularly the intermediate snowbed species G. acaulis and G. montanum. The photoprotective responses after snowmelt were idiosyncratic: G. montanum rapidly accumulated xanthophyll-cycle pigments, tocopherol and flavonoid glycosides; while S. alpina showed the largest increase in plastochromanol-8 and chlorophyll contents and the greatest changes in optical properties. Climate warming scenarios might shift the snowmelt date and consequently alter the effectiveness of photoprotection mechanisms, potentially changing the fitness outcome of the different strategies adopted by alpine forbs.Peer reviewe

    Association of the MYH9 gene polymorphisms with chronic renal disease secondary to hypertensive nephrosclerosis, in a Caucasian population

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    Background: Hypertensive nephrosclerosis (HN) is a chronic kidney disease (CKD) associated to essential hypertension, but their causal relationship is controversial. New evidence suggests that MYH9 gene alterations are associated with HN in African Americans. The aim of this study is to investigate the role of this gene in Spanish Caucasians. Methods: We compare high-risk MYH9 variants of patients with HN recruited according to standard clinical criteria (CKD stages 3-5), with essential hypertensives without renal disease (estimated glomerular filtration rate (eGFR) > 60 ml/min/1,73m2 and albuminuria < 300 mg/g creatinine), and also CKD patients with HN and progressive impairment of renal function with those who were stable. Diabetics were excluded. Results: A blood sample was obtained for genetic study of 238 patients with HN-CKD and 233 hypertensive controls. The rs3752462-T and rs4821480-T (risk alleles for CKD) were more frequent in the CKD group, but without significant difference. We found no differences for these SPNs with blood pressure, creatinine, albuminuria or renal disease progression. Conclusions: The effect of two common MYH9 single nucleotide polymorphisms (SPNs) on the development of CKD secondary to HN in our Spanish Caucasian population is low or zero; in any case less than that found in other, mainly African Americans.Funding: This work was supported by grant Red de Investigación Renal-REDINREN from the Instituto Carlos III, and with funds from the Fundación Renal Iñigo Álvarez de Toledo (Iñigo Álvarez de Toledo Kidney Foundation) in the Molecular Genetics Grou

    Organizacion social del trabajo en la posmodernidad

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    trabajo conjunto derivado del cuerpo academico de la facultad de ciencias politicas. salud mental y vida cotidianadesde la posmodernidad se analiza y contribuye a la explicacion del fenomeno desde el trabajo precario, la violencia laboral, las universidades y la perspectiva de genero. La discusion invade el mundo del trabajo, el estress, mobing y , terrorismo laboral que se expande desde un cotidiano que puede estar en el hogar con el trabajo domestico hasta realidades del mundo empresarial y academico. Se observan sintomas y cuadro de organizaciones toxicas que contaminan el cotidiano y la salud social

    Chlorophyll a fluorescence illuminates a path connecting plant molecular biology to Earth-system science

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    Remote sensing methods enable detection of solar-induced chlorophyll a fluorescence. However, to unleash the full potential of this signal, intensive cross-disciplinary work is required to harmonize biophysical and ecophysiological studies. For decades, the dynamic nature of chlorophyll a fluorescence (ChlaF) has provided insight into the biophysics and ecophysiology of the light reactions of photosynthesis from the subcellular to leaf scales. Recent advances in remote sensing methods enable detection of ChlaF induced by sunlight across a range of larger scales, from using instruments mounted on towers above plant canopies to Earth-orbiting satellites. This signal is referred to as solar-induced fluorescence (SIF) and its application promises to overcome spatial constraints on studies of photosynthesis, opening new research directions and opportunities in ecology, ecophysiology, biogeochemistry, agriculture and forestry. However, to unleash the full potential of SIF, intensive cross-disciplinary work is required to harmonize these new advances with the rich history of biophysical and ecophysiological studies of ChlaF, fostering the development of next-generation plant physiological and Earth-system models. Here, we introduce the scale-dependent link between SIF and photosynthesis, with an emphasis on seven remaining scientific challenges, and present a roadmap to facilitate future collaborative research towards new applications of SIF.Peer reviewe

    La enseñanza del metabolismo: retos y oportunidades

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    En el marco del Proyecto de Innovación Educativa de la Universidad de Málaga PIE15-163, cuya descripción y resultados incluimos, decidimos que esta era una excelente oportunidad para reflexionar acerca de la enseñanza del metabolismo y de poner por escrito dichas reflexiones en un libro. Quisimos y pudimos contar con la colaboración de buena parte de los compañeros del Departamento de Biología Molecular y Bioquímica que apoyaron con su firma el proyecto PIE15-163 y extendimos nuestra invitaciones a otros compañeros de dentro y fuera de la Universidad de Málaga. Del Departamento de Biología Molecular y Bioquímica de la Universidad de Málaga hemos recibido aportaciones de los catedráticos Victoriano Valpuesta Fernández, Ana Rodríguez Quesada y Antonio Heredia Bayona, los profesores titulares María Josefa Pérez Rodríguez, José Luis Urdiales Ruiz e Ignacio Fajardo Paredes y la investigadora postdoctoral y profesora sustituta interina Beatriz Martínez Poveda. De otros departamentos de la Universidad de Málaga hemos contado con las aportaciones de la catedrática del Departamento de Especialidades Quirúrgicas, Bioquímica e Inmunología Pilar Morata Losa, del catedrático del Departamento de Lenguajes y Ciencias de la Computación José Francisco Aldana Montes y los componentes de su grupo de investigación Khaos Ismael Navas Delgado, María Jesús García Godoy, Esteban López Camacho y Maciej Rybinski, del catedrático Ángel Blanco López, del Área de Conocimiento de Didáctica de las Ciencias Experimentales y del Doctor en Ciencias Químicas y actual doctorando del Programa de Doctorado "Educación y Comunicación Social" Ángel Luis García Ponce. De fuera de la Universidad de Málaga, hemos contado con las aportaciones del catedrático de la Universidad de La Laguna Néstor V. Torres Darias, de la catedrática de la Universitat de les Illes Balears Pilar Roca Salom y de sus compañeros los profesores Jorge Sastre Serra y Jordi Oliver, de los catedráticos de la Universidad de Granada Rafael Salto González y María Dolores Girón González y su colaborador el Dr. José Dámaso Vílchez Rienda, del profesor titular de la Universidad de Alcalá Ángel Herráez, del investigador postdoctoral de la Universidad de Erlangen (Alemania) Guido Santos y del investigador postdoctoral de la empresa Brain Dynamics Carlos Rodríguez Caso.Hemos estructurado los contenidos del libro en diversas secciones. La primera presenta el Proyecto en cuyo marco se ha gestado la iniciativa que ha conducido a la edición del presente libro. La segunda sección la hemos titulado "¿Qué metabolismo?" e incluye diversas aportaciones personales que reflexionan acerca de qué metabolismo debe conocer un graduado en Bioquímica, en Biología, en Química, en Farmacia o en Medicina, así como una aportación acerca de qué bioquímica estructural y enzimología son útiles y necesarias para un estudiante que vaya a afrontar el estudio del metabolismo. La tercera sección, "Bases conceptuales", analiza las aportaciones del aprendizaje colaborativo, el contrato de aprendizaje y el aprendizaje basado en la resolución de casos prácticos a la mejora del proceso enseñanza-aprendizaje dentro del campo de la Bioquímica y Biología Molecular, más concretamente en el estudio del metabolismo. La cuarta sección se titula "Herramientas", es la más extensa e incluye las diversas aportaciones centradas en propuestas concretas de aplicación relevantes y útiles para la mejora de la docencia-aprendizaje del metabolismo. Sigue una sección dedicada a presentar de forma resumida los "Resultados" del proyecto PIE15-163. El libro concluye con una "coda final" en la que se reflexiona acerca del aprendizaje de la Química a la luz de la investigación didáctica.Patrocinado por el Proyecto de Innovación Educativa de la Universidad de Málaga PIE15-16

    Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort

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    Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2, 445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD
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