Effects of waterlogging during grain filling on yield components, nitrogen uptake and grain quality in bread wheat

Waterlogging stress frequently affects wheat production in the current conditions. The aim of this work was to evaluate the effect of waterlogging during grain filling on grain yield components, nitrogen uptake and partitioning and gluten composition and quality in bread wheat. Two greenhouse experiments were conducted under contrasting environmental conditions in Azul, Buenos Aires, in a completely randomized design with three replicates. The cultivar chosen was Klein León and the waterlogging treatment was imposed from 5 days after anthesis to maturity. The effects of waterlogging during grain filling in wheat depended on explored environmental conditions: early sowing vs. late sowing. Waterlogging had not significant effects on the most variables at early sowing conditions. However, the delaying in sowing date (higher temperature and radiation) enhance the effects of waterlogging: i) reducing grain weight by 41% and total nitrogen uptake by 51%; ii) reducing the ratio between the contents of high and low molecular weight glutenin subunits, affecting gluten composition; and iii) increasing the sodium dodecyl sulfate test from 79 to 108 mm, which correlates positively with the gluten strength. Reductions in grain weight due to waterlogging during grain filling affect the milling quality, although changes in protein composition may increase or maintain the gluten strength (SDSS) under particular conditions

Identificación de proteínas que participan en una ruta de desmetilación activa de DNA en Arabidopsis thaliana

DNA methylation (5-methylcytosine, 5-meC) is an important epigenetic mark for transcriptional gene silencing that plays critical roles in regulation of developmental genes, genomic imprinting, X chromosome inactivation and transposon silencing. Methylation landscapes are established by the combined actions of methylation and demethylation reactions. The mechanisms responsible for active DNA demethylation in mammalian cells are still poorly understood. However, in plants there is convincing genetic and biochemical evidence that a subfamily of DNA glycosylases typified by Arabidopsis ROS1 (REPRESSOR OF SILENCING 1) remove 5-meC from DNA, initiating its replacement by unmethylated cytosine through a base excision repair (BER) process. After 5-meC removal, ROS1 and its homologous cleave the phophodiester backbone, generating a substantial fraction of products containing a single-nucleotide gap flanked by 3´- and 5´-phosphate termini. In this work, it has been found that the DNA phosphatase ZDP removes the blocking 3´-phosphate, allowing subsequent DNA polymerization and ligation steps needed to complete demethylation. ZDP and ROS1 interact in vitro and colocalize in vivo in nucleoplasmic foci. It has also been found that extracts from zdp mutant plants are unable to complete DNA demethylation in vitro, and mutations in ZDP cause DNA hypermethylation and transcriptional silencing of a reporter transgene. Furthermore, genome-wide methylation analysis in zdp mutant plants identified hundreds of hypermethylated endogenous loci. Our results also indicate that, besides a role during DNA demethylation, ZDP participates in the repair of DNA damage, probably by processing single-strand breaks (SSB) generated either directly by DNA-damaging agents or indirectly as repair intermediates. This work also examined the possible role of plant XRCC1 (X-ray cross complementing group protein 1) in DNA demethylation. Our results suggest that XRCC1 is a component of plant BER and functions at several stages during active DNA demethylation. Thus, XRCC1 interacts with ROS1 and ZDP and stimulates their enzymatic activities in vitro. By other hand, cell extracts from xrcc1 mutant plants exhibit a reduced capacity to complete DNA demethylation, and XRCC1 is required for efficient gap-tailoring and DNA ligation. Altogether, the results show that ZDP and XRCC1 function downstream of ROS1 in the active DNA demethylation pathway in plants, and contribute to understand the role of DNA repair mechanisms in the modification of epigenetic patterns.La metilación del DNA (5-metilcitosina, 5-meC) es una marca epigenética que promueve el silenciamiento génico y desempeña un papel importante en la regulación del desarrollo, la impronta génica, la inactivación del cromosoma X y el silenciamiento de elementos transponibles. Los patrones de metilación se establecen por la acción combinada de mecanismos de metilación y desmetilación. Los mecanismos responsables de la desmetilación activa del DNA en animales no se conocen con exactitud. Sin embargo, en plantas hay convincentes pruebas genéticas y bioquímicas de que proteínas de una subfamilia de DNA glicosilasas, tipificadas por la proteína de ROS1 (REPRESSOR OF SILENCING 1) de Arabidopsis, eliminan la 5-meC del DNA, iniciando su sustitución por una citosina no metilada a través de un proceso análogo a la reparación por escisión de bases (Base Excision Repair, BER). Tras la eliminación de la 5-meC como base libre, ROS1 y sus homólogos rompen el esqueleto azúcar-fosfato del DNA, generado entre otros productos un hueco mono-nucleotídico flanqueado por extremos 3´-P y 5´-P. En esta tesis doctoral se ha demostrado que ZDP, una fosfatasa de DNA, procesa el grupo 3´-P y genera un extremo 3´-OH que puede ser usado por DNA polimerasas para rellenar el hueco y completar la desmetilación. ZDP y ROS1 interaccionan in vitro y co-localizan in vivo en las mismas regiones nucleoplásmicas. También se ha demostrado que plantas mutantes zdp son incapaces de completar la desmetilación in vitro, y que las mutaciones en ZDP causan la hipermetilación y el consiguiente silenciamiento transcripcional de un transgén reportero. Además, un análisis de metilación a escala genómica ha revelado que el DNA de plantas mutantes zdp contiene cientos de regiones que se encuentran hipermetiladas. Por otra parte, los resultados de este trabajo indican que ZDP también desempeña un papel en la reparación de daños en el DNA, probablemente procesando roturas de cadena sencilla generadas directamente por agentes genotóxicos o surgidas indirectamente como intermediarios de reparación. También se ha examinado el posible papel de XRCC1 (X-ray cross complementing group protein 1) en la ruta de desmetilación activa de DNA. Nuestros resultados indican que XRCC1 es un componente del mecanismo de BER en plantas y que participa en varias etapas de la desmetilación. XRCC1 interacciona con ROS1 y ZDP, estimulando las actividades enzimáticas de ambas proteínas in vitro. Los extractos celulares de plantas mutantes xrcc1 muestran una menor capacidad de completar la desmetilación, y XRCC1 facilita tanto la eliminación del grupo 3´-P catalizada por ZDP como el paso final de ligación del DNA. En definitiva, los resultados de esta tesis demuestran que ZDP y XRCC1 funcionan con posterioridad a ROS1 en una ruta de desmetilación activa del DNA en plantas, y contribuyen a entender el papel de la maquinaria de reparación del DNA en la modificación de los patrones epigenéticos

Pharmaceutical care, prerequisite for quality in evidence based health care

La salud es un concepto condicionado por diversos determinantes que conjuntamente interactúan y condicionan la aparición y la extensión de alteraciones en la salud de las poblaciones. Por eso es ya evidente la limitada capacidad de los servicios de salud para ser eficaces contra la enfermedad y es necesario articular políticas que involucren a otros sectores a fin de conseguir la máxima eficacia en las actuaciones para mejorar la salud. El medicamento y el farmacéutico han jugado un papel en la eficacia de los servicios sanitarios para resolver problemas de salud; la Atención Farmacéutica entendida como un método sistemático para la detección, prevención y resolución de los problemas relacionados con los medicamentos (PRM) se configura con enorme trascendencia para obtener respuestas sobre los elementos que condicionan la aparición de los diversos PRM y la afectación de su eficacia terapéutica, aportando indicaciones que harán posible conseguir minimizar sus consecuencias. La Atención Farmacéutica responde al enfoque de salud que la OMS ha pretendido desde sus propuestas de Salud para Todos en el año 2000 que han sido renovadas con la actual estrategia de Salud para Todos en el Siglo XXI. La investigación es una herramienta que se necesita desarrollar de manera eficaz y continua y en este sentido, la investigación aplicada en el campo de los PRM en patologías con estas características es la clave para arrojar luz sobre ellos, sus factores determinantes y las respuestas capaces de superar el efecto negativo que sobre la eficacia de los tratamientos tienen los PRM.Health is a concept conditioned by various determinants interacting jointly and which condtions the appearance and extension of the changes in the population´s health. Therefore the limited capacity of the health services in the fight against illnesses, thus it is necessary to make policies which includes the other sectors so as to obtain maximum efficiency in bettering health care performances. The drugs and the pharmacist have played an important role in the health´s services efficiency in solving health problems; Pharmaceutical Care understood as a systematic method for the detection, prevention and resolution of the problems related to drugs (PRM), is worked out with great significance so as to obtain answers about the elements which condition the appearance of the various PRM and the effectiveness of its therapeutical efficiency; supplying the indications which will make possible the lessening of its consequences. Pharmaceutical Care, answers the health view prevailing proposal, “Health for all in the year 2000”. This has been renewed by the actual strategy of “Health for All in the XXIst Century”. Research is a tool which needs to be developed in an efficient and continuous manner, and in this sense, research applied to the PRM field in pathologies which show these characteristics, is the key to throw some light on them, on their determinant factors and the answers which are capable of overcoming the negative effect which the PRM has over the treatments efficiency

The DNA Repair Protein XRCC1 Functions in the Plant DNA Demethylation Pathway by Stimulating Cytosine Methylation (5-meC) Excision, Gap Tailoring, and DNA Ligation

Background: Active DNA demethylation in plants is initiated by 5-meC DNA glycosylases of the ROS1/DME family and continued through a base excision repair pathway. Results: XRCC1 stimulates ROS1-initiated demethylation and is required for efficient processing of post-excision intermediates. Conclusion: XRCC1 functions at several stages during active DNA demethylation. Significance: This study identifies a new component of the active DNA demethylation pathway in Arabidopsis

The mechanical performance of recycled slate waste fiber composites based on unsaturated polyester resins

In the last few decades, there has been increasing social awareness for environmental conservation, which is driving the development of composite materials based on natural fibers. These new materials have interesting properties that allow for their use in a variety of applications. This study deals with the development of composite materials based on unsaturated polyester resins reinforced with recycled mineral fibers, such as slate fibers obtained from slate production waste, which have similar properties to glass fiber. The mechanical properties of these composites have been determined by tensile and flexural/bending tests. The influence of various variables such as matrix composition (flexible polyester content) and the weight percentage of fiber added to mechanical properties were evaluated. The flexible/rigid polyester content varied from 0 to 40% and the fiber one from 0 to 30 wt%. Composites with ≥20 wt% of slate fiber reinforcement are shown to have tensile (35 MPa) and flexural (57 MPa) strengths that can compete with materials reinforced with artificial fibers

Solute effects on edge dislocation pinning in complex alpha-Fe alloys

Reactor pressure vessel steels are well-known to harden and embrittle under neutron irradiation, mainly because of the formation of obstacles to the motion of dislocations, in particular, precipitates and clusters composed of Cu, Ni, Mn, Si and P. In this paper, we employ two complementary atomistic modelling techniques to study the heterogeneous precipitation and segregation of these elements and their effects on the edge dislocations in BCC iron. We use a special and highly computationally efficient Monte Carlo algorithm in a constrained semi-grand canonical ensemble to compute the equilibrium configurations for solute clusters around the dislocation core. Next, we use standard molecular dynamics to predict and analyze the effect of this segregation on the dislocation mobility. Consistently with expectations our results confirm that the required stress for dislocation unpinning from the precipitates formed on top of it is quite large. The identification of the precipitate resistance allows a quantitative treatment of atomistic results, enabling scale transition towards larger scale simulations, such as dislocation dynamics or phase field.Fil: Pascuet, Maria Ines Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Constituyentes. Departamento de Materiales; ArgentinaFil: Martínez, E.. Los Alamos National High Magnetic Field Laboratory; Estados UnidosFil: Monnet, G.. EDF–R&D; FranciaFil: Malerba, L.. SCK•CEN. Structural Materials Expert Group. Nuclear Materials Institute; Bélgic

Estudio cinético de la desdiazoación en medio acuoso del tetrafluorborato de bencenodiazonio

The kinetic analyses carried out at different temperatures (20ºC - 40ºC) indicate that the dediazoniation process of thebenzenediazonium ion (BZ) is of the order of one, with BZ at A = 2,3.1015 s-1 and Ea = 112,5 kJ.mol-1 for the Arrheniusequation, and ΔH‡ = 110,0 kJ.mol-1 and ΔS‡ = 40,7 J.K-1.mol-1 for the Eyring equation. The chromatographic resultsreveal that BZ decomposes through a heterolytic process mediated by the aryl ion. The presence of Cu(I) or Cu(II) saltsand ascorbic acid produce a change in the reaction mechanism. The intermediate compounds produced in these conditionsare stable species that may be transported in the bloodstream. The model studied suggests a possible explanation for thelocalisation of tumours produced by the administration of BZ in rats.Los análisis cinéticos realizados a diferentes temperaturas (20º C - 40º C) indican que el proceso de desdiazoacióndel ion bencenodiazonio (BZ) es de orden uno respecto a BZ siendo A = 2,3.1015 s-1 y Ea = 112,5 kJ.mol-1 en laecuación de Arrhenius así como ΔH‡ = 110,0 kJ.mol-1 y ΔS‡ = 40,7 J.K-1.mol-1 para la ecuación de Eyring. Losresultados cromatográficos revelan que BZ se descompone por un proceso heterolítico mediado por el catión arilo.La presencia de sales Cu(I) o de Cu(II) y ácido ascórbico produce un cambio del mecanismo de reacción. Loscompuestos intermedios originados en estas condiciones son especies estables que pueden ser transportadas en lasangre. El modelo estudiado sugiere una posible explicación para la localización descrita en la literatura para lostumores producidos por la administración de BZ a ratas

Honest sexual signalling mediated by parasite and testosterone effects on oxidative balance

Extravagant ornaments evolved to advertise their bearers' quality, the honesty of the signal being ensured by the cost paid to produce or maintain it. The oxidation handicap hypothesis (OHH) proposes that a main cost of testosterone-dependent ornamentation is oxidative stress, a condition whereby the production of reactive oxygen and nitrogen species (ROS/RNS) overwhelms the capacity of antioxidant defences. ROS/RNS are unstable, very reactive by-products of normal metabolic processes that can cause extensive damage to key biomolecules (cellular proteins, lipids and DNA). Oxidative stress has been implicated in the aetiology of many diseases and could link ornamentation and genetic variation in fitness-related traits. We tested the OHH in a free-living bird, the red grouse. We show that elevated testosterone enhanced ornamentation and increased circulating antioxidant levels, but caused oxidative damage. Males with smaller ornaments suffered more oxidative damage than those with larger ornaments when forced to increase testosterone levels, consistent with a handicap mechanism. Parasites depleted antioxidant defences, caused oxidative damage and reduced ornament expression. Oxidative damage extent and the ability of males to increase antioxidant defences also explained the impacts of testosterone and parasites on ornamentation within treatment groups. Because oxidative stress is intimately linked to immune function, parasite resistance and fitness, it provides a reliable currency in the trade-off between individual health and ornamentation. The costs induced by oxidative stress can apply to a wide range of signals, which are testosterone-dependent or coloured by pigments with antioxidant properties

Percepción del paciente mayor polimedicado sobre el rol del farmacéutico comunitario

Introducción: Actualmente casi un 80% del gasto sanitario español corresponde a las personas mayores de 65 años que, debidoa su pluripatología, se convierten en pacientes polimedicados. El farmacéutico comunitario es uno de los agentes de salud que puede ayudar a controlar este gasto y mejorar la calidad deluso de los medicamentos debido a su cercanía y accesibilidad, aunque actualmente sólo se le reconozca un rol dispensador demedicamentos. Objetivos: Explorar la percepción que tiene el paciente mayor polimedicado sobre el rol del farmacéutico. Material y métodos: Se utilizó un método exploratorio basado en la investigación cualitativa, usando como medio de obtención deinformación la entrevista semiestructurada y como marcos teóricos la Teoría del Rol complementada con la Teoría de las Creenciasen Salud. Resultados: Los pacientes mayores polimedicados identifi cancon el rol de profesional sanitario principalmente a su médicode cabecera y al personal de enfermería, relegando al farmacéuticoa funciones de índole menor y, sobre todo, con un rol dispensador de medicamentos y productos sanitarios, aunque resaltan la gran accesibilidad y la confi anza que tienen con este profesional. Conclusión: Los pacientes mayores polimedicados en España esperan del farmacéutico un buen trato y un rol dispensador. Esto puede deberse a la baja expectativa que se tiene del farmacéutico para realizar servicios profesionales distintos de los clásicos (dispensación). Los farmacéuticos deberían empezar a cambiar su rol actual implantando servicios para que la percepcióndel paciente cambie