Genetic Dissection of the Signaling Cascade that Controls Activation of the <i>Shigella</i> Type III Secretion System from the Needle Tip

Many Gram-negative bacterial pathogens use type III secretion systems (T3SSs) for virulence. The Shigella T3SS consists of a hollow needle, made of MxiH and protruding from the bacterial surface, anchored in both bacterial membranes by multimeric protein rings. Atop the needle lies the tip complex (TC), formed by IpaD and IpaB. Upon physical contact with eukaryotic host cells, T3S is initiated leading to formation of a pore in the eukaryotic cell membrane, which is made of IpaB and IpaC. Through the needle and pore channels, further bacterial proteins are translocated inside the host cell to meditate its invasion. IpaD and the needle are implicated in transduction of the host cell-sensing signal to the T3S apparatus. Furthermore, the sensing-competent TC seems formed of 4 IpaDs topped by 1 IpaB. However, nothing further is known about the activation process. To investigate IpaB’s role during T3SS activation, we isolated secretion-deregulated IpaB mutants using random mutagenesis and a genetic screen. We found ipaB point mutations in leading to defects in secretion activation, which sometimes diminished pore insertion and host cell invasion. We also demonstrated IpaB communicates intramolecularly and intermolecularly with IpaD and MxiH within the TC because mutations affecting these interactions impair signal transduction

Interactive inspection of complex multi-object industrial assemblies

The final publication is available at Springer via http://dx.doi.org/10.1016/j.cad.2016.06.005The use of virtual prototypes and digital models containing thousands of individual objects is commonplace in complex industrial applications like the cooperative design of huge ships. Designers are interested in selecting and editing specific sets of objects during the interactive inspection sessions. This is however not supported by standard visualization systems for huge models. In this paper we discuss in detail the concept of rendering front in multiresolution trees, their properties and the algorithms that construct the hierarchy and efficiently render it, applied to very complex CAD models, so that the model structure and the identities of objects are preserved. We also propose an algorithm for the interactive inspection of huge models which uses a rendering budget and supports selection of individual objects and sets of objects, displacement of the selected objects and real-time collision detection during these displacements. Our solution–based on the analysis of several existing view-dependent visualization schemes–uses a Hybrid Multiresolution Tree that mixes layers of exact geometry, simplified models and impostors, together with a time-critical, view-dependent algorithm and a Constrained Front. The algorithm has been successfully tested in real industrial environments; the models involved are presented and discussed in the paper.Peer ReviewedPostprint (author's final draft

Valores morales en el comportamiento de los estudiantes

En la Escuela de Educación Básica María Luisa Viteri Aguilar del cantón Naranjito, los estudiantes en su mayoría provienen de entornos socio afectivos donde falta el afecto, dificultando la capacidad de autorreflexionar de los niños y niñas; otros han sufrido la ruptura de su núcleo familiar causando en ellos un desarrollo emocional inestable; mientras que, unos estudiantes pertenecen a hogares que carecen de valores morales lo cual limita su concentración; todo esto sumado a la mala influencia de los medios comunicativos dando pie a un comportamiento inadecuado y un rendimiento escolar poco satisfactorio. Todo aquello demuestra que la familia juega un papel muy elemental en cuanto a la formación de una persona con valores morales, aunque éstos deben ser inculcados durante la educación que se recibe en las aulas, no deja al margen a los padres, quienes son los principales responsables de inculcar en sus hijos, principalmente con el ejemplo, los principios morales que consideren necesarios y deseables. Por esta razón, hemos emprendido esta investigación con el afán de diseñar un manual didáctico de valores morales, para los docentes y así propiciar una educación en valores morales que estimule al educando a mejorar su comportamiento escolar, desde las aulas, determinando la importancia de concienciar los valores morales para mejorar el comportamiento de los estudiantes del séptimo grado, evaluando el grado de afecto en el entorno socioafectivo de los estudiantes del séptimo grado a través de una observación y analizando el nivel de aplicación de los valores morales como eje trasversal en los estudiantes inmersos en el plan de lección del docente; todo esto con el noble propósito de mejorar las relaciones entre estudiantes y docentes, además de incluir la práctica de valores morales en el proceso educativ

Desarrollo de un tubo de colores para estimulación de niños y adultos mayores

Este dispositivo permite emitir luces de colores con el objetivo de ayudar a los niños y niñas a percibir e identificar los colores de mejor manera, desarrollar el estímulo visual y el desarrollo de la memoria. Para la elaboración del dispositivo se requiere de materiales completamente seguros para cualquier usuario debe tener un contacto directo con el dispositivo. La creación de este dispositivo nos ayudó a desarrollar nuestra creatividad e imaginación al momento de armar el tubo de colores debido a que las personas mostrarán cierto interés por los detalles que resaltan y dan un toque de originalidad al diseño del tubo

Steps for Shigella Gatekeeper Protein MxiC Function in Hierarchical Type III Secretion Regulation

Type III secretion systems are complex nanomachines used for injection of proteins from Gram-negative bacteria into eukaryotic cells. Although they are assembled when the environmental conditions are appropriate, they only start secreting upon contact with a host cell. Secretion is hierarchical. First, the pore-forming translocators are released. Second, effector proteins are injected. Hierarchy between these protein classes is mediated by a conserved gatekeeper protein, MxiC, in Shigella. As its molecular mechanism of action is still poorly understood, we used its structure to guide site-directed mutagenesis and to dissect its function. We identified mutants predominantly affecting all known features of MxiC regulation as follows: secretion of translocators, MxiC and/or effectors. Using molecular genetics, we then mapped at which point in the regulatory cascade the mutants were affected. Analysis of some of these mutants led us to a set of electron paramagnetic resonance experiments that provide evidence that MxiC interacts directly with IpaD. We suggest how this interaction regulates a switch in its conformation that is key to its functions

Differences in Salmonella enterica serovar Typhimurium strain invasiveness are associated with heterogeneity in SPI-1 gene expression

Most studies on Salmonella enterica serovar Typhimurium infection focus on strains ATCC SL1344 or NTCC 12023 (ATCC 14028). We have compared the abilities of these strains to induce membrane ruffles and invade epithelial cells. S. Typhimurium strain 12023 is less invasive and induces smaller membrane ruffles on MDCK cells compared with SL1344. Since the SPI-1 effector SopE is present in SL1344 and absent from 12023, and SL1344 sopE mutants have reduced invasiveness, we investigated whether 12023 is less invasive due to the absence of SopE. However, comparison of SopE+ and SopE− S. Typhimurium strains, sopE deletion mutants and 12023 expressing a sopE plasmid revealed no consistent relationship between SopE status and relative invasiveness. Nevertheless, absence of SopE was closely correlated with reduced size of membrane ruffles. A PprgH–gfp reporter revealed that relatively few of the 12023 population (and that of the equivalent strain ATCC 14028) express SPI-1 compared to other S. Typhimurium strains. Expression of a PhilA–gfp reporter mirrored that of PprgH–gfp in 12023 and SL1344, implicating reduced signalling via the transcription factor HilA in the heterogeneous SPI-1 expression of these strains. The previously unrecognized strain heterogeneity in SPI-1 expression and invasiveness has important implications for studies of Salmonella infection

La formación en Moodle en el Campus Virtual de la Universitat de Barcelona

Este trabajo describe la planificación de la formación en Moodle en la UB. Se recoge la información descriptiva acumulada en los siguientes aspectos: tipología de cursos ofertados, facultades implicadas, participación docente, etc. desde su implantación en el curso 2006-07 hasta la actualidad. Se ha producido una implementación generalizada del uso de Moodle en la docencia cotidiana de los profesores de la UB. Como consecuencia, se están replanteando las metodologías docentes con un enfoque más acorde a las directrices que emanan del EEES. Se ha iniciado la exploración de su uso avanzado por parte de diferentes equipos docentes, al incluirlo en el desarrollo de nuevos proyectos de innovación docente de nuestra universidad

Pleistocene and Holocene peopling of Jerada province, eastern Morocco: introducing a research project

The Aïn Beni Mathar – Guefaït (ABM-GFT) region in Eastern Morocco is the object of an archaeological, palaeontological, geological and geochronological research project, led by an international team since 2006. The research in this former fluvio-lacustrine basin, roughly 2000 km2, has revealed a significant number of Pleistocene and Holocene sites. Here we introduce the research project, that we conduct in the region, the main issues it aims to address, and the results already obtained

Le peuplement humain pendant le Pléistocène et l’Holocène dans la province de Jerada, Maroc oriental : introduction d’un projet de recherche

[EN] The Aïn Beni Mathar – Guefaït (ABM-GFT) region in Eastern Morocco is the object of an archaeological, palaeontological, geological and geochronological research project, led by an international team since 2006. The research in this former fluvio-lacustrine basin, roughly 2000 km2, has revealed a significant number of Pleistocene and Holocene sites. Here we introduce the research project, that we conduct in the region, the main issues it aims to address, and the results already obtained.[FR] Depuis 2006, la région de Aïn Beni Mathar – Guefaït (ABM-GFT) au Maroc Oriental, fait l’objet d’un projet de recherche en archéologie, paléontologie, géologie et géochronologie, mené par une équipe internationale. Ces recherches ont permis la découverte d’un nombre significatif de gisements d’âge Pléistocène et Holocène, dans un ancien bassin fluvio-lacustre, qui s’étend sur une surface de 2000 km2. Notre objectif ici est de présenter le projet de recherche, que nous entamons dans la région, la problématique qu’il traite et les premiers résultats déjà obtenus.Funding for this research was provided by: Palarq Foundation, Spanish Ministry of Culture and Sport (Ref: 42-T002018N0000042853 & 170-T002019N0000038589), Direction of Cultural Heritage (Ministry of Culture and Communication, Morocco), Faculty of Sciences (Mohamed 1r University of Oujda, Morocco), INSAP (Institut National des Sciences de l’Archéologie et du Patrimoine), Spanish Ministry of Science, Innovation and Universities (Ref: CGL2016-80975-P, CGL2016-80000-P, PGC2018-095489-B-I00 and PGC2018-093925-B-C31) and Research Groups Support of the Catalonia Government (2017 SGR 836 and 2017 SGR 859). R.S-R, M.G.CH., J.I.M., A.C., F.R., A.R.-H., E.A., I.E., F.B., J.A., HA.B., P.S., P.P., D.L., I.R. y E.M. research is funded by CERCA Programme/ Generalitat de Catalunya. J.I.M. and A.R.-H research is funded by the Spanish Minitry of Science and Innovation under the “María de Maeztu” Program for Unities of Excellence (CEX2019-000945-M). M.S. has been granted by the Research Program UAM Tomás y Valiente 2019. C.T. is funded by the Ramón y Cajal Program. M.F. and M.E.A. received a fellowship under the Erasmus Mundus Scholarship of the European Education and Culture Executive Agency in the Master in Quaternary and Prehistory at URV. The research of M.D. is funded by the Australian Research Council (ARC) Future Fellowship Grant FT150100215 and the Ramón y Cajal Program (RYC2018-025221-I). P.P. has been granted a post-doctoral post under the Spanish Ministry of Science and Innovation “Juan de la Cierva-Incorporación” Program (Ref. IJC2020-044108-I). E.M-R. is beneficiary of a PTA Ref. PTA201714619-I. G.G.-A. has been granted a “Ford - Apadrina la Ciencia” contract. C.D.-C has been granted a Fundación Atapuerca fellowship. A.C.A. was funded by Junta de Castilla y León (project BU235P18) and the European Regional Development Fund (ERDF). The Institut Catalá de Paleoecologia Humana i Evolució Social (IPHES-CERCA) has received financial support from the Spanish Ministry of Science and Innovation through the ‘María de Maeztu’ program for Units of Excellence (CEX2019-000945-M).Peer reviewe