Gut microbiota-motility interregulation:Insights from in vivo, ex vivo and in silico studies

The human gastrointestinal tract is home to trillions of microbes. Gut microbial communities have a significant regulatory role in the intestinal physiology, such as gut motility. Microbial effect on gut motility is often evoked by bioactive molecules from various sources, including microbial break down of carbohydrates, fibers or proteins. In turn, gut motility regulates the colonization within the microbial ecosystem. However, the underlying mechanisms of such regulation remain obscure. Deciphering the inter-regulatory mechanisms of the microbiota and bowel function is crucial for the prevention and treatment of gut dysmotility, a comorbidity associated with many diseases. In this review, we present an overview of the current knowledge on the impact of gut microbiota and its products on bowel motility. We discuss the currently available techniques employed to assess the changes in the intestinal motility. Further, we highlight the open challenges, and incorporate biophysical elements of microbes-motility interplay, in an attempt to lay the foundation for describing long-term impacts of microbial metabolite-induced changes in gut motility

Bead-Based Hydrodynamic Simulations of Rigid Magnetic Micropropellers

The field of synthetic microswimmers, micro-robots moving in aqueous environments, has evolved significantly in the last years. Micro-robots actuated and steered by external magnetic fields are of particular interest because of the biocompatibility of this energy source and the possibility of remote control, features suited for biomedical applications. While initial work has mostly focused on helical shapes, the design space under consideration has widened considerably with recent works, opening up new possibilities for optimization of propellers to meet specific requirements. Understanding the relation between shape on the one hand and targeted actuation and steerability on the other hand requires an understanding of their propulsion behavior. Here we propose hydrodynamic simulations for the characterization of rigid micropropellers of any shape, actuated by rotating external magnetic fields. The method consists of approximating the propellers by rigid clusters of spheres. We characterize the influence of model parameters on the swimming behavior to identify optimal simulation parameters using helical propellers as a test system. We then explore the behavior of randomly shaped propellers that were recently characterized experimentally. The simulations show that the orientation of the magnetic moment with respect to the propeller's internal coordinate system has a strong impact on the propulsion behavior and has to be known with a precision of ≤ 5° to predict the propeller's velocity-frequency curve. This result emphasizes the importance of the magnetic properties of the micropropellers for the design of desired functionalities for potential biomedical applications, and in particular the importance of their orientation within the propeller's structure

RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica: Repression of flhDC transcription by a RcsB-RflM complex

The bacterial flagellum enables directed movement of Salmonella enterica towards favorable conditions in liquid environments. Regulation of flagellar synthesis is tightly controlled by various environmental signals at transcriptional and post- transcriptional levels. The flagellar master regulator FlhD₄C₂ resides on top of the flagellar transcriptional hierarchy and is under autogenous control by FlhD₄C₂- dependent activation of the repressor rflM. The inhibitory activity of RflM depends on the presence of RcsB, the response regulator of the RcsCDB phosphorelay system. In this study, we elucidated the molecular mechanism of RflM- dependent repression of flhDC. We show that RcsB and RflM form a heterodimer that coordinately represses flhDC transcription independent of RcsB phosphorylation. RcsB-RflM complex binds to a RcsB box downstream the P1 transcriptional start site of the flhDC promoter with increased affinity compared to RcsB in the absence of RflM. We propose that RflM stabilizes binding of unphosphorylated RcsB to the flhDC promoter in absence of environmental cues. Thus, RflM is a novel auxiliary regulatory protein that mediates target specificity of RcsB for flhDC repression. The cooperative action of the RcsB-RflM repressor complex allows Salmonella to fine-tune initiation of flagellar gene expression and adds another level to the complex regulation of flagellar synthesis

Simulando problemas en el ciclo lectivo 2013

Se describe una experiencia realizada en el ciclo lectivo 2013 en la asignatura Modelos y Simulación, fundamentada en el Aprendizaje Basado en Problemas y su abordaje con métodos propios de la asignatura. El designio que guía su abordaje es fomentar el pensamiento crítico, resolutivo y mejorar la construcción de conocimientos de los estudiantes enfocándose en la elaboración de posibles soluciones frente a abstracciones de problemas reales y su resolución con métodos de simulación.Palabra(s) clave(s): Modelos y Simulación, Aprendizaje Basado en Problemas, Construcción del conocimiento

Elaboración de gráficas de predicción para la retención de arsénico en el suelo del la reserva ecológica los Ilinizas en la provincia de Cotopaxi durante el periodo 20-21.

The presence of arsenic in soil is a risk to ecosystems and human health, although its presence can be natural or anthropogenic, by generating a predictive model of arsenic retention in the Los Ilinizas Ecological Reserve it is possible to determine the effects on the environment. The study and sampling area is located in the Iliniza, south of the hot springs of Cunugyacu parish of San Juan of Pastocalle, county Latacunga, province of Cotopaxi. Its objective is to generate a predictive graphs for arsenic retention in the different sampling points of the Los Ilinizas Ecological Reserve study area by means of comparative graphs. Composite soil sampling was carried out in a grid every 100m, obtaining 22 samples, taking into account the presence of natural factors associated with volcanic activity in the area. Laboratory analyses were performed at the university facilities using the colorimeter test for arsenic, using a solution of 500 ug As/ L, 1 g soil sample, and different agitation periods from 30 minutes to 48 hours, in order to plot the arsenic retention behavior when acting together solution+soil. By experimentally analyzing each sample and using comparison graphs, a predictive model was generated that yields arsenic retention of 10% to 35% in less agitation time (30 minutes to 8 hours) and 42% to 53% arsenic retention in longer hours (12 to 48 hours).La presencia de arsénico en los suelos es un riesgo para ecosistemas y la salud humana, a pesar que su existencia puede ser natural o antropogénica, al generar un modelo de predicción de retención de Arsénico en la Reserva Ecológica Los Ilinizas se puede determinar los efectos al ambiente. El área de estudio y muestreo está ubicada en el Iliniza sur a la altura de las termas de Cunugyacu parroquia San Juan de Pasto calle, cantón Latacunga, provincia de Cotopaxi. Tiene como objetivo generar gráficas de predicción para retención de Arsénico en los diferentes puntos de muestreo del área de estudio de la Reserva Ecológica Los Ilinizas por medio de gráficas comparativas. Se realizó muestreo compuesto del suelo en forma de cuadricula cada 100m obteniendo 22 muestras, teniendo en cuenta presencia de factores naturales asociados con actividad volcánica de la zona. Los análisis de laboratorio se realizaron en las instalaciones de la universidad usando el test de colorímetro para arsénico, empleando una solución de 500 ug As/ L, 1 g de muestra de suelo y diferentes periodos de agitación de 30 min a 48 h, con el fin de graficar el comportamiento de retención de arsénico al actuar conjuntamente solución +suelo. Al analizar experimentalmente cada muestra y usando gráficas de comparación, se generó un modelo predictivo que arroja retención de arsénico de un 10% a 35% en menor tiempo de agitación (30min a 8 horas) y de 42% a 53% de retención de arsénico en horas mayores (12 a 48 horas

High-speed motility originates from cooperatively pushing and pulling flagella bundles in bilophotrichous bacteria.

Funder: Max-Planck-Gesellschaft; FundRef: http://dx.doi.org/10.13039/501100004189Funder: IMPRS on Multiscale BiosystemsFunder: French National Research Agency; FundRef: http://dx.doi.org/10.13039/501100001665; Grant(s): ANR Tremplin-ERC: ANR-16-TERC-0025-01Bacteria propel and change direction by rotating long, helical filaments, called flagella. The number of flagella, their arrangement on the cell body and their sense of rotation hypothetically determine the locomotion characteristics of a species. The movement of the most rapid microorganisms has in particular remained unexplored because of additional experimental limitations. We show that magnetotactic cocci with two flagella bundles on one pole swim faster than 500 µm·s-1 along a double helical path, making them one of the fastest natural microswimmers. We additionally reveal that the cells reorient in less than 5 ms, an order of magnitude faster than reported so far for any other bacteria. Using hydrodynamic modeling, we demonstrate that a mode where a pushing and a pulling bundle cooperate is the only possibility to enable both helical tracks and fast reorientations. The advantage of sheathed flagella bundles is the high rigidity, making high swimming speeds possible

Construcción de un software para experimentar en técnicas de modelado y simulación de existencias

Se describe un software orientado a apoyar el aprendizaje de modelado y simulación de um problema de existencias. El simulador se diseñó y construyó orientado a fines pedagógicos para su utilización en la asignatura “Modelos y Simulación” para facilitar la generación de prácticas interactivas y diversos experimentos con finalidades de estudios comparativos. El trabajo se compone de cuatro secciones. En la primera sección se sintetiza contexto educativo en el que se encuadra el trabajo. La segunda sección resume la metodologia aplicada. En la tercera sección se describe el caso de estudio tratado y las funcionalidades del producto generado. Para finalizar se mencionan consideraciones a modo de conclusiones preliminares.Red de Universidades con Carreras en Informática (RedUNCI

Gestión de la información en Educación Superior. Una experiencia de evolución del software con sistemas gestores de contenidos

La Educación Superior ofrece un vasto dominio para el diseño y desarrollo de soluciones tecnologías orientadas a la gestión de la información. Se presenta una experiencia fundadas en conceptos teóricos de la evolución del software, en particular su mantenimiento, actividad que permite modificar el mismo conservando su integridad. Esta actividad continúa durante su tiempo de vida, dado que en la práctica sufren cambios para su permanencia y utilidad; existiendo diferentes factores que inciden en su ejecución, lo que  permiten clasificarlos en mantenimiento correctivo y perfectivo, entre otros. Los Sistemas Gestores de  Contenidos o CMS son ampliamente aplicados en una  diversidad de soluciones para mediar la comunicación con los usuarios finales. En la propuesta se resume una práctica atinente a la evolución del software centrada en el mantenimiento perfectivo aplicado en un sistema gestor de contenidos de código abierto.Artículo revisado por pare

Mantenimiento Perfectivo en un Gestor de Contenidos: Una Experiencia para la Especificación de Consultas Dinámicas

Los Sistemas Gestores de Contenidos o CMS son ampliamente aplicados en una diversidad de soluciones para mediar la comunicación con los usuarios finales. En este trabajo se expone una experiencia de personalización de un CMS de libre distribución considerada ésta como un mantenimiento perfectivo, abordando las actividades que propone estándar IEEE 1219 para gestionar dicho proceso

A Retrospective Epidemiological Study on the Association of Bullous Pemphigoid and Neurological Diseases

Bullous pemphigoid is a rare chronic recurrent dermatosis that is often reported in association with various neurological diseases. No investigation involving a large number of patients has ever been carried out to demonstrate such an association. This study was accomplished by analysing the discharge diagnosis of all hospitalized patients, both day-patients and inpatients, during a 5-year period (1995–2000) covering a total population group of 934,023 living in a region of Italy that has approximately 1,200,000 inhabitants. The results support the hypothesis of an association between bullous pemphigoid, multiple sclerosis and Parkinson's disease on a highly significant statistical basis. The aetiopathogenic mechanisms and the causes that induce the loss of immunological tolerance are not yet understood