Ingeniería y función del dominio lectina de FimH en el ensamblaje de fimbrias tipo 1 de escherichia coli

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 15-12-200

Las prácticas de laboratorio como estrategia didáctica para el aprendizaje por descubrimiento de las soluciones químicas

Las prácticas de laboratorio como estrategia didáctica para el aprendizaje por descubrimiento de las soluciones químicas se articula a las acciones de mejora de la Institución Educativa María Montessori, fomentando las competencias científicas, y progresos en los resultados de las pruebas, de sus estudiantes, específicamente grado undécimo. Su sustento teórico es el modelo de aprendizaje por descubrimiento guiado que plantea Jerome Bruner. A partir de él se reestructura del enfoque de las prácticas de laboratorio relacionadas con la química; se validan los conocimientos previos de los estudiantes, sus intereses y circunstancias contextuales; se promueve el aprendizaje autónomo y se recupera la didáctica de la escucha: fortaleciendo las competencias ciudadanas, comunicativas y el trabajo cooperativo. La estrategia didáctica promueve un valor agregado desde su implementación interdisciplinar, evidenciado en las propuestas y desarrollo de las prácticas de laboratorio, en donde se vinculan saberes distintos a los tratados en la química.Abstract : Laboratory practices as a didactic strategy for learning by discovery of chemical solutions is articulated to the improvement actions of the Maria Montessori Educational Institution, fostering scientific competences, and progress in the test results, of its students, specifically in eleventh grade. Its theoretical sustenance is the model of learning by guided discovery posed by Jerome Bruner. From it, the focus of laboratory practices related to chemistry is restructured; the students' prior knowledge, interests and contextual circumstances are validated; Autonomous learning is promoted and the didactic of listening is recovered: strengthening citizenship, communication skills and cooperative work. The didactic strategy promotes an added value from its interdisciplinary implementation, evidenced in the proposals and development of laboratory practices, where different knowledge is related to those treated in chemistry

IoT-based air quality monitoring systems for smart cities: A systematic mapping study

The increased level of air pollution in big cities has become a major concern for several organizations and authorities because of the risk it represents to human health. In this context, the technology has become a very useful tool in the contamination monitoring and the possible mitigation of its impact. Particularly, there are different proposals using the internet of things (IoT) paradigm that use interconnected sensors in order to measure different pollutants. In this paper, we develop a systematic mapping study defined by a five-step methodology to identify and analyze the research status in terms of IoT-based air pollution monitoring systems for smart cities. The study includes 55 proposals, some of which have been implemented in a real environment. We analyze and compare these proposals in terms of different parameters defined in the mapping and highlight some challenges for air quality monitoring systems implementation into the smart city context

Fucose Sensing Regulates Bacterial Intestinal Colonization

The mammalian gastrointestinal (GI) tract provides a complex and competitive environment for the microbiota1. Successful colonization by pathogens depends on scavenging nutrients, sensing chemical signals, competing with the resident bacteria, and precisely regulating expression of virulence genes2. The GI pathogen enterohemorrhagic E.coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression3–4. Here we show that these systems control the expression of a novel two-component signal transduction system, named FusKR, where FusK is the histidine sensor kinase (HK), and FusR the response regulator (RR). FusK senses fucose and controls expression of virulence and metabolic genes. This fucose-sensing system is required for robust EHEC colonization of the mammalian intestine. Fucose is highly abundant in the intestine5. Bacteroides thetaiotaomicron (B.theta) produces multiple fucosidases that cleave fucose from host glycans, resulting in high fucose availability in the gut lumen6. During growth in mucin, B.theta contributes to EHEC virulence by cleaving fucose from mucin, thereby activating the FusKR signaling cascade, modulating EHEC’s virulence gene expression. Our findings suggest that EHEC uses fucose, a host-derived signal made available by the microbiota, to modulate EHEC pathogenicity and metabolism

Autotransporters but not pAA are critical for rabbit colonization by Shiga toxin-producing Escherichia coli O104:H4

The outbreak of diarrhea and hemolytic uremic syndrome that occurred in Germany in 2011 was caused by a Shiga toxin-producing enteroaggregative Escherichia coli (EAEC) strain. The strain was classified as EAEC due to the presence of a plasmid (pAA) that mediates a characteristic pattern of aggregative adherence on cultured cells, the defining feature of EAEC that has classically been associated with virulence. Here, we describe an infant rabbit-based model of intestinal colonization and diarrhea caused by the outbreak strain, which we use to decipher the factors that mediate the pathogen’s virulence. Shiga toxin is the key factor required for diarrhea. Unexpectedly, we observe that pAA is dispensable for intestinal colonization and development of intestinal pathology. Instead, chromosome-encoded autotransporters are critical for robust colonization and diarrheal disease in this model. Our findings suggest that conventional wisdom linking aggregative adherence to EAEC intestinal colonization is false for at least a subset of strains

Host-specific differences in the contribution of an extended spectrum β-lactamase (ESBL) IncI1 plasmid to intestinal colonisation by Escherichia coli O104:H4

Objectives. To assess stability and contribution of a large extended spectrum β-lactamase (ESBL)-containing IncI1 plasmid to intestinal colonization by Escherichia coli O104:H4 in two different mammalian hosts. Methods. Specific-pathogen-free 3-day old New Zealand White rabbits and conventionally-reared 6-week-old weaned lambs were orally infected with wild-type E. coli O104:H4 or the ESBL-plasmid cured derivative, and the recovery of bacteria in intestinal homogenates and faeces monitored over time. Results. Carriage of the ESBL plasmid had differing impacts on E. coli O104:H4 colonisation of the two experimental hosts. The plasmid cured strain was recovered at significantly higher levels than wild type during late-stage colonization of rabbits, but at lower levels than wildtype in sheep. Regardless of the animal host, the ESBL plasmid was stably maintained in virtually all in vivo passaged bacteria that were examined. Conclusions. These findings suggest that carriage of ESBL plasmids has distinct effects on the host bacterium depending upon the animal species it encounters and demonstrates that, as for E. coli O157:H7, ruminants could represent a potential transmission reservoir.</p

A Poly-N-Acetylglucosamine−Shiga Toxin Broad-Spectrum Conjugate Vaccine for Shiga Toxin-Producing Escherichia coli

ABSTRACT Many pathogens produce the β-(1−6)-linked poly-N-acetylglucosamine (PNAG) surface polysaccharide that is being developed as a broadly protective antimicrobial vaccine. However, it is unknown whether systemically injected PNAG vaccines or antibodies would provide protective immunity against pathogens confined to the gastrointestinal tract such as Shiga toxin (Stx)-producing Escherichia coli (STEC), an important group of gastrointestinal (GI) pathogens for which effective immunotherapeutics are lacking. To ascertain whether systemic IgG antibody to PNAG impacts this infectious situation, a vaccine consisting of a synthetic nonamer of nonacetylated PNAG, 9GlcNH2, conjugated to the Shiga toxin 1b subunit (9GlcNH2-Stx1b) was produced. Rabbit antibodies raised to the conjugate vaccine were tested for bacterial killing and toxin neutralization in vitro and protection against infection in infant mice. Cell surface PNAG was detected on all 9 STEC isolates tested, representing 6 STEC serogroups, including E. coli O157:H7. Antibody to the 9GlcNH2-Stx1b conjugate neutralized Stx1 potently and Stx2 modestly. For O157:H7 and O104:H4 STEC strains, antibodies elicited by the 9GlcNH2-Stx1b conjugate possessed opsonic killing and bactericidal activity. Following intraperitoneal injection, antibodies to both PNAG and Stx were needed for infant mouse protection against O157 STEC. These antibodies also mediated protection against the Stx2-producing O104:H4 strain that was the cause of a recent outbreak in Germany, although sufficient doses of antibody to PNAG alone were protective against this strain in infant mice. Our observations suggest that vaccination against both PNAG and Stx, using a construct such as the 9GlcNH2-Stx1b conjugate vaccine, would be protective against a broad range of STEC serogroups

Análisis del factor de gestión ambiental en la sostenibilidad por medio del uso de redes neuronales autoorganizadas

El propósito de este trabajo es analizar el factor de gestión ambiental dentro de la temática del desarrollo sostenible a partir de una revisión de artículos publicados en revistas académicas y científicas incluyendo revisadas por pares, usando como referente la base de datos proquest. Este trabajo corresponde a un resultado intermedio del proyecto "Análisis de los factores de impacto, gestión y protección de la sostenibilidad ambiental mediante un proceso de mapeo de conceptos basado en inteligencia artificial" y la metodología empleada fue la revisión bibliométrica de conceptos usando el apoyo de las redes neuronales autoorganizadas SOM, en el entorno de MATLAB

N-Terminal Type III Secretion Signal of Enteropathogenic Escherichia coli Translocator Proteins▿

We report that the N terminus of the type III secretion system translocator proteins EspB, EspD, and EspA mediate protein secretion and translocation from wild-type enteropathogenic Escherichia coli and hypersecretion from sepL and sepD mutants. EspA containing the translocation signal of Map and Tir containing the secretion signal of EspA are biologically active

HISTORIAS DE VIDA, RACISMO Y EXCLUSIÓN SOCIAL

Estudiar el RACISMO y una de sus consecuencias la EXCLUSIÓN SOCIAL en una dimensión de Etnoeducación en el Caribe, se constituye en una travesía intelectual de encuentros y desencuentros de las interacciones culturales, mediadas por imaginarios, costumbres, prácticas y convicciones de los pueblos que en su dinámica natural se expresan en comportamientos de exclusión, no contemplados en las normativas políticas de los países, donde la interculturalidad y la integración de los pueblos es el ideal planetario. Este artículo marca rutas desde la literatura del tema que enriquece las investigaciones, y hallazgos de las Historias de Vida, que cada día tributan a un tejido que desde el racismo y la exclusión han merecido la atención especialmente en la escuela