Sensors based on carbon nanotube field-effect transistors and molecular recognition approaches

La unión de las propiedades de los CNT con los principios de reconocimiento molecular se presenta como una base adecuada para el desarrollo de sensores altamente específicos. El objetivo de la presente tesis ha sido desarrollar sensores químicos, del tipo transistores de efecto campo (CNTFET), basados en interacciones receptor-analito, mediante el empleo de los nanotubos de pared sencilla (SWCNT), que actúan como transductores de la señal analítica.Las principales etapas de la parte experimental han sido: Crecimiento de SWCNT con la técnica de deposición química en fase vapor. Integración de los SWCNTs en sistemas CNTFET. Empleo del CNTFET como base del sensor en distintos campos utilizando modelos de reconocimiento molecular. Dependiendo del tipo de funcionalización de los SWCNTs se pueden obtener sensores para proteínas, iones, etc. Como resultado, se han desarrollado y estudiado sensores basados en CNTFETs para la detección distintos analitos de interés, como son la Inmunoglobulina G Humana, los iones potasio y el dióxido de azufre.The general objective of this thesis is to develop chemical sensors whose sensing capacities are based on the principle of molecular recognition and where the transduction is carried out by single-walled carbon nanotubes (SWCNT).The sensing device used is the carbon nanotube field-effect transistor (CNTFET). The new structure of the CNTFET allows nanotubes to be integrated at the surface of the devices, thus exploiting SWCNTs' sensitivity to changes in their environment. The functionalization of SWCNTs with several types of molecular receptors such as antibodies, ion selective membranes, and synthetic receptors, achieve a high selectivity towards the analyte of interest. This thesis shows that CNTFETs can be used for the successful selective detection of different types of target analytes. These can be biomolecules such as antigens, small compounds such as cations or gas-phase compounds such as SO2

The Role of Microbial Ecology in Glacier Retreat

Glaciers have been considered too hostile to harbor life for a long time. However, they are now recognized as unique biomes dominated by microbial communities which maintain active biochemical routes. Microbial communities inhabiting glaciers are diverse depending on the type of glacier and the area studied. Some glaciers have a marine margin and finish in a calving front, with partly or completely temperate tidewater tongues, this establishes important differences with respect to glaciers with a land margin. Depending on the glacier area studied, microorganisms are also characteristic as they establish a vertical food chain, from the surface photosynthesizers in upper illuminated layers to heterotrophs confined in the inner part. Glaciers are retreating in many areas of the world due to global warming. Microorganisms are their most abundant and unknown occupants. They play a main role, carrying out key processes in the development of soil and facilitating plant colonization when glaciers have ultimately retired. These microorganisms are perfectly adapted to their harsh environment and are very susceptible to environmental changes. This chapter summarizes the role of microbial ecology as indicator of the conservation status of glaciers

Competencia percibida y motivación durante la iniciación en la práctica del tenis

Este trabajo se llevó a cabo con la finalidad de analizar los principales factores motivacionales en la iniciación a la práctica del tenis. Se analizó el papel del control personal (competencia percibida y autovaloración) sobre la motivación para la participación deportiva y sobre la motivación intrínseca por los entrenamientos. Asimismo, se estudiaron diversos indicadores sociodemográficos como precursores de diferencias motivacionales y de control personal. Un total de 89 sujetos de entre 8 y 18 años, alumnos de 2 escuelas de tenis, participaron en el estudio, durante el cual se recogió información acerca de todas estas variables, mediante cuestionarios cuyas cualidades psicométricas también fueron analizadas en detalle. Los resultados, en general, indican que la edad, el género y el club de pertenencia, pueden afectar tanto al control personal como a la motivación deportiva. Por otra parte, y en consonancia con estudios previos, el control personal parece jugar un papel destacado en los perfiles motivacionales de los jugadores de tenis durante la etapa de iniciación deportiva.We designed this work in order to investigate the main motivational factors at starting sport practice. We studied the role of personal control (perceived competence and self-appraisal) on both motivation for sport practicing and intrinsic motivation for training. Also, the role of several socialdemographical parameters, as the origin of both motivational and personal control differences, was analysed. 89 subjects, all them between 8 and 18 years old and tennis practitioners at one of two sport schools, participated in this study. It was collect information in regard to all variables in what we were concerned, by means of questionaires that were analysed psychometrically. Results show age, gender and club as agents influenciating both personal control and sport motivation. Also, personal control appears to be a major factor that affects motivational profiles in tennis players at stage of sport iniciation

Microbial Community Structure and Metabolic Networks in Polar Glaciers

Polar glaciers are inhabited by numerous microorganisms including representatives of bacteria, archaea, microeukaryotes, and viruses. Low temperature is a main factor when considering polar glaciers as extreme environments. However, desiccation, low nutrients availability, ultraviolet irradiation, and photoreactive chemistry do also significantly influence their challenging life. Glaciers are highly selective and confined habitats, which make them favorable environments for adaptation and speciation. Depending on the glacier area studied, microorganisms establish a vertical food chain, from the surface photosynthesizers in upper illuminated layers to chemoautotrophs and heterotrophs confined to the inner part. These regions are rich not only in biodiversity but also in new mechanisms of adaptation to the environment, since selection acts with a particular intensity. Glaciers are retreating in many areas of the world due to global warming. When glaciers have ultimately withdrawn, microorganisms play a main role, carrying out key processes in the development of soil and facilitating plant colonization. These features make them unique and interesting for the study and protection of the biological heritage. Metagenomics have allowed a deeper understanding of microbial ecology and function of polar glacier microbial communities. In this review, we present a complete analysis of the microbial diversity in these ecosystems and include a thorough overview of the metabolic potentials and biogeochemical cycles in polar glacier habitats

Desarrollo y manufactura de proteínas para nichos de mercado no ocupado del sector farmaceútico y veterinario

Comunicaciones a congreso

STRUCTURAL-FUNCTIONAL ANALYSIS OF LACTO-N-BIOSIDASE FROM Bifidobacterium bifidum: A POTENTIAL BIOCATALYST FOR THE PRODUCTION OF HUMAN MILK OLIGOSACCHARIDES

Els efectes beneficiosos que els oligosacàrids de la llet materna (OLM) confereixen a la salut dels lactants s'ha estudiat durant anys. Aquests oligosacàrids proporcionen una barrera protectora i un suport nutritiu essencials, als quals no tenen accés els nens que no prenen llet materna. La llet humana és considerada única respecte a la resta de llets de mamífers pel que fa a la quantitat i la complexitat d'oligosacàrids. Actualment, s'han identificat més de 130 estructures químiques diferents de OLM, i no es disposa de cap recurs natural que proporcioni accés a aquestes estructures tan complexes i a bastament. De la mateixa manera, la síntesi química és complicada a causa de l'estructura tan complexa i diversa que presenten els OLM, i de moment, la síntesi en gran escala no ha estat possible. La síntesi enzimàtica, en canvi, es presenta com una eina alternativa de síntesi d'aquestes molècules complexes atès que, en la naturalesa els enzims són els responsables de formar enllaços glicosídics entre carbohidrats amb alta regio- i estereoselectivitat. L'objectiu d'aquesta tesi és avaluar l'ús de l'enzim Lacto-N-biosidasa de Bifidobacterium bifidum (LnbB) com un biocatalizador eficient des de dues perspectives diferents: i) l'estudi estructural-funcional de LnbB i ii) la generació de biocatalizadors capaços de sintetitzar l'oligosacàrid d'interès (lacto-N-tetraosa) mitjançant enginyeria de proteïnes en l'enzim LnbB. En aquesta tesi, hem analitzat l'organització dels dominis dels enzims de la família GH20, i, en conseqüència, hem definit dos models d'arquitectures. El Model A conté almenys dos dominis, un domini GH20b no catalític i el GH20 catalític, que sempre es presenta acompanyat d'una α-hèlix extra. En canvi, el Model B consisteix únicament en el domini catalític GH20. Mitjançant l'expressió de diferents formes truncades de LnbB, hem descrit els requeriments estructurals per a la funcionalitat dels enzims GH20, i en particular per LnbB, per tal d’obtenir la unitat funcional mínima que conservi l'activitat enzimàtica. Respecte a la síntesi de la lacto-N-tetraosa usant com a biocatalizador noves proteïnes de LnbB obtingudes mitjançant enginyeria de proteïnes, hem contemplat dues estratègies enzimàtiques diferents. En primer lloc, l'estratègia de glicosintasa, en la qual l'enzim (amb mutació en el residu assistent) és capaç de transferir el corresponent donador activat (sucre sintètic derivat d’oxazolina) a un acceptor, sense hidròlisi del producte. En segon lloc, l'estratègia de transglicosilació millorada, en la qual, una nova generació de mutants en els llocs d'unió a l'acceptor seran capaços d'acomodar de manera més favorable un sucre en lloc d'una molècula d'aigua, i d'aquesta manera, augmentar l'activitat de transglicosilació.Los efectos beneficiosos que los oligosacáridos de la leche materna (OLM) confieren a la salud de los lactantes se han estudiado durante años. Estos oligosacáridos proporcionan una barrera protectora y un soporte nutritivo esenciales, a los que, los niños que no toman leche materna no tienen acceso. La leche humana se considerada única respecto al resto de leches de mamíferos en cuanto a cantidad y complejidad de oligosacáridos. Actualmente, se han identificado más de 130 estructuras químicas diferentes de OLM, y no se dispone de ningún recurso natural que proporcione acceso a estas estructuras tan complejas y en cantidad suficiente. Del mismo modo, la síntesis química es complicada debido a la estructura tan compleja y diversa que presentan los OLM, y por el momento, la síntesis en gran escala no ha sido posible. La síntesis enzimática, en cambio, se presenta como una herramienta alternativa de síntesis de éstas moléculas complejas dado que, en la naturaleza las enzimas son las responsables de formar enlaces glicosídicos entre carbohidratos con alta regio- y estereoselectividad. El objetivo de esta tesis es evaluar el uso del enzima Lacto-N-biosidase de Bifidobacterium bifidum (LnbB) como un biocatalizador eficiente desde dos perspectivas diferentes: i) el estudio estructural-funcional de LnbB y ii) la generación de biocatalizadores capaces de sintetizar el oligosacárido de interés (lacto-N-tetraosa) mediante ingeniería de proteínas en el enzima LnbB. En esta tesis, hemos analizado la organización de los dominios de enzimas GH20, y, en consecuencia, hemos definido dos modelos de arquitecturas de dominio. El Modelo A contiene al menos dos dominios, un dominio GH20b no catalítico y el GH20 catalítico, que siempre se presenta acompañado de una α-hélice extra. Por el contrario, el Modelo B consiste únicamente en el dominio catalítico GH20. Mediante la expresión de diferentes formas truncadas de LnbB, hemos descrito los requerimientos estructurales para la funcionalidad de las enzimas GH20, y en particular para LnbB, de modo que se obtenga la unidad funcional mínima que conserve la actividad enzimática. Respecto a la síntesis de la lacto-N-tetraosa usando como biocatalizador nuevas proteínas de LnbB obtenidas mediante ingeniería, hemos contemplado dos estrategias enzimáticas diferentes. En primer lugar, la estrategia de glicosintasa, en la que el enzima (un mutante en el residuo asistente) es capaz de transferir el correspondiente dador activado (azúcar sintético derivado de oxazolina) a un aceptor, sin hidrólisis del producto. En segundo lugar, la estrategia de transglicosilación mejorada, en la que, una nueva generación de mutantes en los sitios de unión al aceptor serán capaces de acomodar de manera más favorable un aceptor de azúcar en lugar de una molécula de agua, y de este modo, aumentar la actividad de transglicosilación.The potential health benefits of human milk oligosaccharides (HMO) have been studied for many years. It is well known that these oligosaccharides provide a protective barrier and nutritive support that infants with poor access to breast milk do not acquire in the first years of life. Human milk is considered to be unique among mammals in terms of the quantity and complexity of its oligosaccharides. To date, 130 chemical structures within HMO have been identified. No other natural resources provide access to these complex oligosaccharides in such large amounts, and until now, large scale synthesis of HMO has not been possible by any traditional organic chemistry methodology. Enzymatic synthesis is an alternative synthetic tool since enzymes can form the new glycosidic linkage between carbohydrates with high regio- and stereoselectivity. The objective of this thesis is to evaluate the use of Lacto-N-biosidase from Bifidobacterium bifidum (LnbB) as an efficient biocatalyst in the following two ways: i) the structural-functional study of LnbB and ii) protein engineering of LnbB to generate biocatalysts able to synthesize the target lacto-N-tetraose. Here, we have analysed the domain organization of GH20 enzymes, and accordingly, have defined two models of domain architectures. Model A, contains at least two domains, a non-catalytic GH20b domain, and the catalytic GH20 which is always accompanied with an extra α-helix. In contrast, Model B consists only of the catalytic GH20 domain. By expressing different truncated forms of LnbB, we have described the structural requirements for functionality of GH20 enzymes, and in particular for LnbB, to obtain a minimal functional unit that retains the enzymatic activity. With regard to the synthesis of lacto-N-tetraose using new engineered LnbB proteins as biocatalysts, we envisage two different enzymatic strategies. First, the glycosynthase strategy, in which the activated donor is the corresponding synthetic sugar oxazoline and the enzyme, a mutant on the assisting residue, is able to transfer the donor to an acceptor without hydrolysis of the product. Second, the enhanced transglycosidase strategy, in which, a new generation of mutants on the acceptor subsites of the enzyme will be able to more favourably accommodate a sugar acceptor instead of water, and thus, increase transglycosylation activity

Restoration of the Palacio de Mayoralgo in Cáceres (Spain).

[Abstract] The Palace Mayoralgo (13th/16th century), in St. Maria Square in the Old City of Cáceres was acquired it in 1999 to be the headquarters of the Presidency of the Caja de Extremadura. It had been empty and unused for many years, and it was also severely damaged since it was hit by bombs during the Spanish Civil War in 1937. Different well known experts, in a multidisciplinary work, have participated both in the writing of the project to optimize architectural and constructive solutions. The development of the project and the works began in from August 2000 and finished in August 2004. The finding of the Roman archaeological remains at the beginning of the works forced some adjustments in the initial design in order to preserve and protect them. The project and the work carried out have meant, on one hand, a considerable preservation work that increases the value of the Architectural Heritage

Modeling and designing a Listeria monocytogenes control strategy for dry-cured ham taking advantage of water activity and storage temperature

Dry-cured ham is a shelf-stable product that can be contaminated with Listeria monocytogenes due to post-processing operations, compromising the compliance of zero tolerance policies (e.g. US Listeria rule). The present study quantifies the behavior of L. monocytogenes in sliced Spanish dry-cured ham of different water activity (aw) during storage at different temperatures. Inactivation kinetics were estimated by fitting primary models to the experimental data. The effect of temperature and aw on kinetic parameters was characterized through secondary polynomial models. L. monocytogenes viability decreased in all the assayed conditions, confirming that dry-cured ham is not only listeriostatic but listericidal. The fastest and highest reductions were observed at 25 °C, with 1 Log reduction after 6 and 9 days in Iberian and Serrano ham respectively. The work provides scientifically-based data and models to design a low-cost control measure based on a corrective storage as a post-lethality treatment to enhance the accomplishment of zero-tolerance requirements.info:eu-repo/semantics/acceptedVersio