Enseñanza de la evolución humana

En el presente trabajo, cabe destacar el desarrollo de una propuesta docente, incluida dentro de la unidad didáctica “Evolución y origen de la vida”, que consiste en la realización de una actividad grupal de investigación guiada. Se contextualizará en tiempo, contenidos y objetivos. Así como la metodología aplicada y el desarrollo de la actividad en el aula.Departamento de Bioquímica y Biología Molecular y FisiologíaMáster en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanzas de Idioma

Growth in elevated CO2 enhances temperature response of photosynthesis in wheat

The temperature dependence of C3 photosynthesis may be altered by the growth environment. The effects of long-term growth in elevated CO2 on photosynthesis temperature response have been investigated in wheat (Triticum aestivum L.) grown in controlled chambers with 370 or 700 µmol mol-1 CO2 from sowing through to anthesis. Gas exchange was measured in flag leaves at ear emergence, and the parameters of a biochemical photosynthesis model were determined along with their temperature responses. Elevated CO2 slightly decreased the CO2 compensation point and increased the rate of respiration in the light and Rubisco Vcmax, although the latter effect was reversed at 15 ºC. With elevated CO2, Jmax decreased in the 15 ºC-25 ºC temperature range and increased at 30 ºC and 35 ºC. The temperature response (activation energy) of Vcmax and Jmax increased with growth in elevated CO2. CO2 enrichment decreased the RuBP-limited photosynthesis rates at lower temperatures and increased Rubisco- and RuBP-limited rates at higher temperatures. The results show that the photosynthesis temperature response is enhanced by growth in elevated CO2. We conclude that if temperature acclimation and factors such as nutrients or water availability do not modify or negate this enhancement, the effects of future increases in air CO2 on photosynthetic electron transport and Rubisco kinetics may improve the photosynthetic response of wheat to global warming.Spanish National Research and Development Programme (Project BFI2003-01277).Peer reviewe

Epigenetic contribution to successful polyploidizations: variation in global cytosine methylation along an extensive ploidy series in Dianthus broteri (Caryophyllaceae)

Polyploidization is a significant evolutionary force in plants which involves major genomic and genetic changes, frequently regulated by epigenetic factors. We explored whether natural polyploidization in Dianthus broteri complex resulted in substantial changes in global DNA cytosine methylation associated to ploidy. Global cytosine methylation was estimated by high-performance liquid chromatography (HPLC) in 12 monocytotypic populations with different ploidies (2×, 4×, 6×, 12×) broadly distributed within D. broteri distribution range. The effects of ploidy level and local variation on methylation were assessed by generalized linear mixed models (GLMMs). Dianthus broteri exhibited a higher methylation percent (˜33%) than expected by its monoploid genome size and a large variation among study populations (range: 29.3–35.3%). Global methylation tended to increase with ploidy but did not significantly differ across levels due to increased variation within the highest-order polyploidy categories. Methylation varied more among hexaploid and dodecaploid populations, despite such cytotypes showing more restricted geographic location and increased genetic relatedness than diploids and tetraploids. In this study, we demonstrate the usefulness of an HPLC method in providing precise and genome reference-free global measure of DNA cytosine methylation, suitable to advance current knowledge of the roles of this epigenetic mechanism in polyploidization processes.Peer Reviewe

Análisis del proceso de inserción de un soporte antivibratorio

En este Trabajo de Fin de Grado se presenta el análisis del proceso de inserción de un soporte antivibratorio, insertado mediante un ajuste por interferencia y conseguido gracias a la aplicación de elevadas fuerzas de inserción. Partiendo de medidas experimentales de la fuerza de inserción a realizar, el objetivo de este trabajo consiste en predecir dicha fuerza a partir de la presión de contacto que se da en este tipo de ajuste. Esto se realizará mediante un modelo MEF en Solidworks Simulation, que permita determinar esta fuerza en futuros procesos de inserción, sin disponer de resultados experimentales previos. Validaremos este modelo comparando los resultados con un modelo analítico y con las medidas reales disponibles. Debido a las elevadas fuerzas aplicadas, realizaremos además un estudio estático de las tensiones a las que están sometidos determinados componentes de la máquina, con el fin de predecir un posible fallo y así poder evitarlo.Departamento de Ciencias de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodesia y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de FabricaciónGrado en Ingeniería Mecánic

Modelado de un proceso de almacenamiento estacional de energía a través de la conversión de una central hidroeléctrica de regulación en una central con almacenamiento por bombeo

El incremento del uso de energías renovables para la producción de energía eléctrica ha supuesto el desarrollo de sistemas de almacenamiento, los cuales permiten contrarrestar la variabilidad de dichas energías renovables, almacenando la energía cuando hay excedentes y aportando energía a la red cuando la generación no cubre la demanda. Uno de estos sistemas es el almacenamiento hidráulico por bombeo, el cual permite almacenar la energía de forma estacional. En el presente Trabajo de Fin de Máster se estudia, mediante un modelo realizado en lenguaje Python, cómo influye en el almacenamiento estacional de una central hidráulica de regulación, la transformación de la misma en una central de almacenamiento por bombeo, al añadir un embalse inferior de menor capacidad. Se detallan los pasos seguidos en el desarrollo y ajuste del modelo, para finalmente simular una serie de casos supuestos con los que estudiar dicha influencia. A mayores se han comparado los beneficios económicos obtenidos en dichos supuestos con los de un caso real, para comprobar el funcionamiento del modelo.Departamento de Ingeniería Energética y FluidomecánicaMáster en Ingeniería Industria

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

The short term influence of aboveground biomass cover crops on C sequestration and β-glucosidase in a vineyard ground under semiarid conditions

© 2014 Ministerio de Agricultura Pesca y Alimentacion. All Rights Reserved. Tillage and semiarid Mediterranean climatic conditions accelerate soil organic matter losses in Spanish vineyards. Previous studies showed that cover crops can increase soil organic carbon (SOC) in Mediterranean vineyards. The objectives of this study were to evaluate the influence of two different cover crops in the short term on soil C sequestration in a semiarid vineyard and to study the potential use of both β-glucosidase enzimatic activity (GLU) and the GLU/SOC ratio in order to assess the SOC increase. The experiment was carried out in a cv. Tempranillo (Vitis vinifera L.) vineyard on a Oxyaquic Xerorthent soil in Rioja winegrowing region (NE, Spain). The experimental design was established in 2009 with three treatments: conventional tillage; sown barley cover crop (Hordeum vulgare, L.); sown Persian clover cover crop (Trifolium resupinatum L.). Carbon in the aboveground biomass with each cover crop was monitored. Soil was sampled in June 2011 and June 2012, and SOC, GLU and the GLU/SOC ratio were determined. After 3 years both cover crops increased SOC at soil surface with C sequestration rates of 0.47 and 1.19 t C ha–1 yr–1 for BV and CV respectively. GLU and GLU/SOC ratio increased in both cover crops at 0-5 cm soil depth. The C sequestration rates and GLU were related to the cover crops aboveground biomass. In consequence, in semiarid vineyards under cover crops GLU could be an appropriate indicator to asses the increase of SOC and the soil quality improvement in the short-term (2-3 years).This study was supported by the Spanish Ministry of Science, INIA and European Social Fund through project INIA-RTA 2009-00101-00-00. F. Peregrina thanks the INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria) and European Social Fund for its post-doctoral grants and E. Pérez-Álvarez thanks the INIA for her pre-doctoral grant.Peer Reviewe

MSAP markers and global cytosine methylation in plants: a literature survey and comparative analysis for a wild-growing species

Methylation of DNA cytosines affects whether transposons are silenced and genes are expressed, and is a major epigenetic mechanism whereby plants respond to environmental change. Analyses of methylation-sensitive amplification polymorphism (MS-AFLP or MSAP) have been often used to assess methyl-cytosine changes in response to stress treatments and, more recently, in ecological studies of wild plant populations. MSAP technique does not require a sequenced reference genome and provides many anonymous loci randomly distributed over the genome for which the methylation status can be ascertained. Scoring of MSAP data, however, is not straightforward, and efforts are still required to standardize this step to make use of the potential to distinguish between methylation at different nucleotide contexts. Furthermore, it is not known how accurately MSAP infers genome-wide cytosine methylation levels in plants. Here, we analyse the relationship between MSAP results and the percentage of global cytosine methylation in genomic DNA obtained by HPLC analysis. A screening of literature revealed that methylation of cytosines at cleavage sites assayed by MSAP was greater than genome-wide estimates obtained by HPLC, and percentages of methylation at different nucleotide contexts varied within and across species. Concurrent HPLC and MSAP analyses of DNA from 200 individuals of the perennial herb Helleborus foetidus confirmed that methyl-cytosine was more frequent in CCGG contexts than in the genome as a whole. In this species, global methylation was unrelated to methylation at the inner CG site. We suggest that global HPLC and context-specific MSAP methylation estimates provide complementary information whose combination can improve our current understanding of methylation-based epigenetic processes in nonmodel plants.Peer reviewe

Gas exchange acclimation to elevated CO2 in upper-sunlit and lower-shaded canopy leaves in relation to nitrogen acquisition and partitioning in wheat grown in field chambers.

Growth at elevated CO2 often decreases photosynthetic capacity (acclimation) and leaf N concentrations. Lower-shaded canopy leaves may undergo both CO2 and shade acclimation. The relationship of acclimatory responses of flag and lower-shaded canopy leaves of wheat (Triticum aestivum L.) to the N content, and possible factors affecting N gain and distribution within the plant were investigated in a wheat crop growing in field chambers set at ambient (360 μmol mol-1) and elevated (700 μmol mol-1) CO2, and with two amounts of N fertilizer (none and 70 kg ha-1 applied on 30 April). Photosynthesis, stomatal conductance and transpiration at a common measurement CO2, chlorophyll and Rubisco levels of upper-sunlit (flag) and lower-shaded canopy leaves were significantly lower in elevated relative to ambient CO2-grown plants. Both whole shoot N and leaf N per unit area decreased at elevated CO2, and leaf N declined with canopy position. Acclimatory responses to elevated CO2 were enhanced in N-deficient plants. With N supply, the acclimatory responses were less pronounced in lower canopy leaves relative to the flag leaf. Additional N did not increase the fraction of shoot N allocated to the flag and penultimate leaves. The decrease in photosynthetic capacity in both upper-sunlit and lower-shaded leaves in elevated CO2 was associated with a decrease in N contents in above-ground organs and with lower N partitioning to leaves. A single relationship of N per unit leaf area to the transpiration rate accounted for a significant fraction of the variation among sun-lit and shaded leaves, growth CO2 level and N supply. We conclude that reduced stomatal conductance and transpiration can decrease plant N, leading to acclimation to CO2 enrichment.This work was funded by the Spanish ‘Plan Nacional de Investigación y Desarrollo’ (grant N° BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements, chlorophyll and Rubisco activity determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe