Papel de factores de la transcripción y la replicación del ADN en el origen de la inestabilidad genómica.

Mantener la integridad del genoma no es tarea fácil para las células. El ADN sufre constantes ataques de agentes químicos y/o físicos de origen exógeno y endógeno, pero no sólo eso, los propios procesos celulares que emplean el ADN como sustrato también pueden generar daños y roturas. Dos de los procesos más fundamentales para la supervivencia de la célula, la replicación y la transcripción, son a su vez de las fuentes más importantes de daños en el ADN, especialmente en los casos de colisiones entre las maquinarias responsables de ambos procesos. Las colisiones entre transcripción y replicación pueden darse por diversos motivos, como la acumulación de estrés torsional en el ADN, la competencia entre polimerasas por el ADN molde en regiones del genoma con alta tasa de transcripción, o la presencia de secuencias específicas de ADN con tendencia a formar estructuras diferentes a su conformación B canónica. Dentro de esta última clasificación existe un tipo de estructura nucléica que está adquiriendo una creciente relevancia, los bucles R (más conocidos como R-loops). De origen primordialmente co-transcripcional, los R-loops están constituidos por una cadena sencilla de ADN desplazada y un híbrido de ARN:ADN formado entre el ARN y su hebra de ADN molde. Los híbridos de ARN:ADN son estructuras naturales, que presentan mayor estabilidad que la propia doble hélice de ADN, y que participan en diversos procesos celulares, como la replicación del ADN mitocondrial o el cambio de isotipo de las inmunoglobulinas. Sin embargo, la presencia de una cadena sencilla de ADN desplazada, característica de los R-loops, o la capacidad de estos de interferir con la replicación, pueden suponer riesgos para el mantenimiento de la estabilidad de los genomas. La presente tesis se plantea con la meta de avanzar en el conocimiento sobre los mecanismos que dan lugar a la formación y acumulación de los R-loops, y la de descubrir nuevos factores implicados en el mantenimiento de su homeostasis para evitar la aparición de conflictos entre la transcripción y la replicación y la inestabilidad genética que va asociada a ellos. Adicionalmente, empleando el organismo modelo S. cerevisiae, investigamos el funcionamiento de la proteína humana RECQL5, que a día de hoy se considera uno de los factores con el papel más claro y directo en la coordinación de los procesos de transcripción y replicación del ADN. Nuestros resultados apoyan la creciente noción de que la presencia de R-loops en las células es más común de lo que se pensaba inicialmente, incluso en fondos genéticos silvestres. Mediante análisis de secuenciación masiva y estudios bioinformáticos hemos encontrado que los telómeros, el ADN ribosómico (rDNA), los transposones y numerosos genes transcritos por la RNAPII son regiones con enriquecimiento de híbridos de ARN:ADN en una estirpe silvestre, patrón que se mantiene con cierta constancia en mutantes hpr1Δ. Los mutantes en este componente del complejo THO de elongación de la transcripción muestran fenotipos de acumulación de R-loops, hiperrecombinación e inestabilidad genética asociada a la transcripción. Nuestro trabajo sugiere que la diferencia puede no residir en la cantidad de híbridos que se formen en el fondo mutante, si no en ciertas características que diferencien estos R-loops de los presentes en cepas silvestres. Sin embargo, mejoras en la metodología deben ser introducidas antes de poder arrojar conclusiones más definitivas. Paralelamente hemos investigado cómo se originan los R-loops. Actualmente se considera que esencialmente son estructuras formadas durante la trascripción. No obstante, no se puede descartar la posibilidad de que un transcrito pudiera hibridar con otras regiones homólogas del genoma, generando R-loops en trans. Nuestros resultados no muestran ningún indicio de que la formación de R-loops no co-transcripcionales sea independiente de la transcripción, o que su formación tenga un impacto detectable en recombinación. Otros datos que rechazan la hipótesis de que Rad51 tenga un papel activo en la formación de R-loops en el mutante hpr1Δ. Una búsqueda de nuevos factores implicados en la homeostasis de R-loops nos llevó hasta la helicasa de ADN Mph1, FANCM en humanos. Los mutantes de levadura deficientes para esta proteína o su actividad helicasa acumulaban híbridos de ARN:ADN. A pesar de esto, las células mph1Δ no mostraron fenotipos de hiperrecombinación, ni defectos replicativos, ni interacciones genéticas con hpr1 o sen1. Serán necesarios estudios futuros para dilucidar si el papel de Mph1 en la eliminación de R-loops es directo o indirecto. Finalmente, hemos demostrado que la helicasa RECQL5 humana puede expresarse en levaduras, donde interacciona con proteínas ortólogas de aquellas humanas con las que se asocia de forma natural, como RNAPII o Rad51. Sin embargo, no hemos podido relacionar la inestabilidad genómica que observamos al expresar RECQL5 en levaduras con defectos producidos en la transcripción o en la replicación. No obstante, describimos por primera vez una relación funcional entre RECQL5 y la helicasa Srs2 de la levadura, que aporta nuevas vías para comprender el funcionamiento de ambas proteínas y sus papeles en el mantenimiento de la estabilidad genómica

A comparative study of the characteristics and physical behaviour of different packing materials commonly used in biofiltration

In this study, the characteristics and physical behaviour of 8 different packing materials were compared. The materials were selected according to previous works in the field of biofiltration including organic and inorganic or synthetic materials. Results pre-selected those more acceptable support materials for the main function they have to perform in the biological system: high surface contact, rugosity to immobilize the biomass, low pressure drop, nutrients supply, water retentivity or a commitment among them. Otherwise, pressure drop have been described by means of the respective mathematic expressions in order to include phenomena in the classical biofiltration models.Peer ReviewedPostprint (author's final draft

The incidence of incentives for t-commerce acceptance: improving television as a distribution channel

Purpose This paper aims to explore the impact of incentives on the behavioral intention to use electronic commerce through interactive television to enhance a deeper understanding of how television platforms can improve the attractiveness of television to enterprises as a channel of communication and distribution. Design/methodology/approach This research uses a questionnaire to collect empirical data on preferences related to perceived usefulness, perceived ease of use, perceived enjoyment, attitude toward the use of t-commerce, behavioral intention to use t-commerce and incentives. The measurement scales of the variables were tested using exploratory factor analysis. The hypotheses were tested using the results of forgotten effects analysis applied to the incidences of incentives on the precedents of the behavioral intention to use t-commerce. Findings The findings suggest that there are no significant direct incidences between incentives and the behavioral intention to use t-commerce, but the direct incidence is only part of the total incidence and on many occasions is only a small part, as the result of causal relationships between causes and effects. The results indicate indirect incidences between incentives and the behavioral intention to use t-commerce through its precedents. Practical implications Marketing managers of television platforms may consider the use of incentives to encourage behavioral intention to use t-commerce to achieve the development of interactive television as a distribution channel. Originality/value Research on t-commerce acceptance, especially research that uses extrinsic variables, is scarce. This paper addresses that gap by exploring the use of incentives to attract users

A fuzzy asymmetric TOPSIS model for optimizing investment in online advertising campaigns

The high penetration of the Internet and e-commerce in Spain during recent years has increased companies' interest in this medium for advertising planning. In this context Google offers a great advertising inventory and perfectly segmented content pages. This work is concerned with the optimization of online advertising investments based on pay-per-click campaigns. Our main goal is to rank and select different alternative keyword sets aimed at maximizing the awareness of and traffic to a company's website. The keyword selection problem with online advertising purposes is clearly a multiple-criteria decision-making problem additionally characterized by the imprecise, ambiguous and uncertain nature of the available data. To address this problem, we propose a technique for order of preference by similarity to ideal solution (TOPSIS)-based approach, which allows us to rank the alternative keyword sets, taking into account the fuzzy nature of the available data. The TOPSIS is based on the concept that the chosen alternative should have the shortest distance from the positive ideal solution and the longest distance from the negative ideal solution. In this work, due to the characteristics of the studied problem, we propose the use of an asymmetric distance, allowing us to work with ideal solutions that differ from the maximum or the minimum. The suitability of the proposed model is illustrated with an empirical case of a stock exchange broker's advertising investment problem aimed at generating awareness about the brand and increasing the traffic to the corporative website

Comparison of organic packing materials for toluene biofiltration

he paper focuses on the operation of a pilot plant with four biofilters operated in parallel for determining the suitability of coconut fiber, peat, compost from the digested sludge of a wastewater treatment plant and pine leaves as packing materials for biofiltration of toluene. Physical characteristics of packing materials such as specific surface area, density, pore size and elemental composition were determined for each packing material. Biological activity and packing capabilities related to toluene removal were determined during the startup and operation of the four biofilters under different conditions of nutrients, watering and inlet air relative humidity supply. Nutrient addition was key in improving removal efficiency (RE) and elimination capacity (EC) of biofilters. Feeding of medium with nutrients increased the RE and the EC by a factor of 2 to 4 than these found when supplying only tap water. Additionally, when extra nitrogen was supplied in the medium, RE and EC increased by a factor of 2. Nutrient addition also lead to a microbial population change from bacterial to fungal biofilters. It was denoted that watering control is necessary to improve fungal biofilters performance in terms of ensuring a proper washout of acidic by-products to avoid fungi inhibition and consequent lowered removal capacities.Peer ReviewedPostprint (published version

The Effectiveness of Advanced Practice Nurses with Respect to Complex Chronic Wounds in the Management of Venous Ulcers

This study aims to evaluate the effectiveness of advanced practice nurses with respect to complex chronic wounds (APN-CCWs) in the care of patients with venous ulcers. A multicentric, quasi-experimental pre-post study was conducted without a control group in the sanitary management areas where the APN-CCW program is being piloted. The intervention consisted of a mass training of clinical nurses from the participating districts on the proper management of injuries and the use of compression therapy. The data were collected through a specifically constructed questionnaire with questions regarding descriptive variables of injuries and their treatment. A total of 643 professionals responded (response rate of 89.1%), attending to a total population of 707,814 inhabitants. An increase in multilayer bandage use by 15.67%, an increase in elastic bandage use by 13.24%, and a significant decrease in the referral of patients to consultation with hospital specialists was achieved, from 21.08% to 12.34%. The number of patients referred to the APNs was 13.25%, which implied a resolution rate of 94.08% of their injuries. In conclusion, the coordination by the APN-CCWs in patients with venous ulcers was effective in improving the continuity of care, in the optimization of resources, and in their care role

Fuzzy logic analysis of effektiveness of the internet advertising formats in interactive television

In a context of technological convergence, the users indistinctly can accede to audiovisual contents through the television and Internet. The object of present work is evaluating the effectiveness of the Internet advertising formats in Interactive Television. The new techniques derived from multivalent logic are an interesting alternative for decision making through order versus classical methods. Therefore, after the treatment of subjective expert input the results reveal that Internet advertising formats are not effectiveness in Interactive Television and it is necessary adapt them for improve the effectiveness of this formats to inform, persuade and remember. = Рассматривается актуальная маркетинговая проблема, связанная с оценкой эффективности интернет-рекламы в формате интерактивного телевидения. Предложен метод для принятия решений при размещении заказа, основанный на многозначной логике и позволяющий эффективно использовать субъективную экспертную информацию

Creativity and innovation in an uncertain environment

Los estudiosos del management han conocido a través del desarrollo de la administración un sinnúmero de teorías y enfoques que han propugnado contribuciones efectivas a su desarrollo. En estos inicios del siglo XXI nos enfrentamos a entornos muchos más inciertos, competitivos y cambiantes, y los enfoques tradicionales no parecen ser una respuesta única y absoluta. Según Tom Peters (1987), no existe compañía segura ante la incertidumbre que nos gobierna habiendo sólo dos maneras de responder a esta era de excelencia insostenible: compra de ideas o creación de ideas. La segunda estrategia es paradójica: aceptar la incertidumbre al enfatizar un conjunto de nuevas bases, calidad y servicios de primera fila, aumentar la respuesta empresarial potenciando la flexibilidad, y continuas y breves apuestas de innovación y mejora buscando la creación de nuevos mercados para productos aparentemente maduros. La Creatividad y la Innovación, resultan ser (para la literatura particularmente) objeto de variadas interpretaciones, alcances, definiciones, etc. y por supuesto, de indicaciones o recomendaciones sobre los caminos que resulten ser más adecuados para su desarrollo y posterior utilización como recurso competitivo. La creciente entropía que afecta el devenir de los negocios, el proceso de globalización, la cada vez mayor competencia en las industrias y la velocidad con que se suscitan los cambios en los ciclos económicos, dan lugar a un contexto en donde tanto la incertidumbre como la escasez de referentes para manejarse en este ámbito se hacen sentir con particular notoriedad. Ello resulta especialmente crítico al emprender nuevas actividades de negocios, donde posiblemente la incertidumbre alcanza un alto grado de presencia, en la cual, ante situaciones cambiantes, nuevas e impredecibles, se requiere actuar con un alto nivel de imaginación y creatividad. Para el desarrollo de una actividad bajo condiciones de incertidumbre se hace absolutamente necesaria la existencia de una estrategia de empresa. Esta no es más que una búsqueda deliberada de un plan de acción que desarrolle una ventaja empresarial competitiva. Para cualquier compañía esta búsqueda es un proceso interactivo que comienza con el reconocimiento del dónde estamos y con qué contamos en este momento. En el pasado, y ciertamente en el pasado empresarial reciente, observamos que la estrategia de las empresas para aumentar beneficios ha perdido el enfoque principal de captación de clientes mediante la extendida costumbre de adquirir otras empresas. El empresario ha confundido la táctica con la estrategia. Big is good. La denominada “merger mania” ha olvidado el aspecto más importante de la estrategia de una empresa, la búsqueda de una ventaja competitiva mediante la CREATIVIDAD y la INNOVACION.The study of management knowed, through the development of a important number of management theories and approaches, that have privided effective contributions to their development, given made the context lived. Now in the XXI century, we face more uncertain environments, competitive and changing, and the traditional approaches do not appear to get the absolute answer. According to Tom Peters (1987), no company is safe from the uncertainty that governs us and there are only two ways : to buy ideas or creation of ideas. The second strategy is paradoxical. To recive the uncertainty emphasizing a set of new quality and services first row, increase the business response, enhancing flexibility, and short bets for continuing innovation and improvement aiming at the creation of new markets for new products. Creativity and Innovation are (especially for literature) the subject of various interpretations, definitions, etc. and of course, directions or recommendations on the ways that are more suitable for development and subsequent use as a competitive resource. The increasing entropy affecting the future of business, the process of globalization, the increased competition in industries and the speed with which changes occur in economic cycles, are in a context where so much uncertainty ans shortage of references for use in this area became very obvious. This is especially critical when undertaking new business activities, where uncertainty is probably a high degree of participation, which, to changing situations, new and unpredictable, we need to act with a high level of imagination and creativity. For the creation of a business under conditions of uncertainty is absolutely necessary to have a corporate strategy. This is a search of a deliberate plan of action to develop a competitive business advantage. For any company this search is an interactive process that begins with the recognition of where we are and what we have at present. In the past, and certainly in the recent business past, we see that the strategy of companies to increase profits has lost the focus of customer retention through the widespread habit of acquiring other companies. The employer has confused tactics with strategy. "Big is good". The so-called "merger mania" has forgotten the most important aspect of the strategy of a company seeking a competitive advantage through creativity and innovation

Influence of crude glycerol load and pH shocks on the granulation and microbial diversity of a sulfidogenic Upflow Anaerobic Sludge Blanket reactor

Bioscrubbers are an environmental-friendly alternative to valorize SO2 contained in flue gases to obtain elemental sulfur as final value-added product. The bottleneck of a SO2 bioscrubber relies on the heterotrophic reduction of the absorbed SO2 to obtain sulfide. In this study, the performance and stability of a sulfidogenic Upflow Anaerobic Sludge Blanket reactor (UASB) using crude glycerol was investigated during 6 months of operation under variable organic loading rates. The UASB presented a maximum elimination capacity and a sulfate removal efficiency of 110 mg S-SO42- L-1 h(-1) and 100%, respectively, when the chemical oxygen demand to sulfate ratio (COD/S-Sulfate) was 8.5 g O-2 g(-1) S-SO42-. The intermediate compounds identified from crude glycerol degradation were mainly propionic and acetic acid, which varied along the sludge bed together with the pH. Microbial diversity analyses of the sulfidogenic granular sludge showed that the most abundant sulfate reducing genera were Desulfovibrio spp. and Desulfobulbus spp. Methanosaeta and other fermentative/acidogenic microorganisms were also found in significant amounts. Particle size distribution analyses showed that biogas production allowed the granulation of the sulfidogenic sludge, which had an average particle size ranging from 729.3 mu m (lower part of the bed) to 391.7 mu m (upper part of the test). A short-term pH shock caused a detrimental effect over the system performance due to degranulation. Concomitantly, biogas production was interrupted and acetic acid was accumulated also causing a significant impact on microbial diversity. Unclassified Clostridiales, Desulfovibrio spp. and Desulfobulbus spp. showed a higher resistance to pH shocks

Water renewal mechanisms of the Bay of Algeciras in the Strait of Gibraltar

The Bay of Algeciras (BA) is a marine environment subject to high levels of anthropogenic pressure. Here we analyze observations collected at the Bay and the results of an ocean circulation model to investigate its circulation and variability. Special attention is paid to the identification of the mechanisms enhancing the exchange of water with the adjacent Strait of Gibraltar and therefore contributing to maintain satisfactory levels of water quality.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech