Estudio del mecanismo de translocación y permeabilización de la toxina adenilato ciclasa de Bordetella pertussis

220 p.De entre todos los factores de virulencia secretados por la bacteria causante de la tos ferina, Bordetella pertussis, la toxina adenilato ciclasa (o ACT) es esencial para la colonización del tracto respiratorio y en el establecimiento de la enfermedad. La ACT forma parte de las toxinas RTX (del inglés Repeats in ToXin), siendo ésta una proteína bifuncional con un dominio formador de poros que se ocupa de la permeabilización de la membrana y un dominio catalítico, el cual se transloca directamente a través de la membrana, catalizando de forma no regulada el ATP intracelular de las células diana en cAMP a niveles suprafisiológicos. La combinación de ambas actividades provoca la citotoxicidad general producida por la toxina.En esta tesis doctoral se han estudiado ambos procesos en células y en membranas modelo. Por una parte se ha descrito una nueva actividad para la toxina, una actividad fosfolipasa A, la cual es indispensable para la translocación directa a través de la membrana del dominio catalítico. Por otra parte, se ha estudiado el proceso de formación de poros en membranas modelo y en células eucariotas, describiendo procesos de inserción, oligomerización, estabilidad y permeabilización.CSIC BIOFISIKA INSTITUTU

Estudio del mecanismo de translocación y permeabilización de la toxina adenilato ciclasa de Bordetella pertussis

220 p.De entre todos los factores de virulencia secretados por la bacteria causante de la tos ferina, Bordetella pertussis, la toxina adenilato ciclasa (o ACT) es esencial para la colonización del tracto respiratorio y en el establecimiento de la enfermedad. La ACT forma parte de las toxinas RTX (del inglés Repeats in ToXin), siendo ésta una proteína bifuncional con un dominio formador de poros que se ocupa de la permeabilización de la membrana y un dominio catalítico, el cual se transloca directamente a través de la membrana, catalizando de forma no regulada el ATP intracelular de las células diana en cAMP a niveles suprafisiológicos. La combinación de ambas actividades provoca la citotoxicidad general producida por la toxina.En esta tesis doctoral se han estudiado ambos procesos en células y en membranas modelo. Por una parte se ha descrito una nueva actividad para la toxina, una actividad fosfolipasa A, la cual es indispensable para la translocación directa a través de la membrana del dominio catalítico. Por otra parte, se ha estudiado el proceso de formación de poros en membranas modelo y en células eucariotas, describiendo procesos de inserción, oligomerización, estabilidad y permeabilización.CSIC BIOFISIKA INSTITUTU

Industrial agglomeration in Costa Rica : a descriptive analysis

This paper investigates the current situation of industrial agglomeration in Costa Rica, utilizing firm-level panel data for the period 2008-2012. We calculated Location Quotient and Theil Index based on employment by industry and found that 14 cantons have the industrial agglomerations for 9 industries. The analysis is in line with the nature of specific industries, the development of areas of concentration around free zones, and the evolving participation of Costa Rica in GVCs

Modelo de gestión de la capacidad competitiva de exportación, de la Empresas Pymes de Olivo; en la región Tacna-Perú

El trabajo de investigación presentado tiene por finalidad dar a conocer cómo afrontan su capacidad competitiva de exportación las pequeñas y medianas empresas (pymes) de olivo de la región Tacna-Perú, con respecto a las herramientas estratégicas de la Ruta Exportadora y de la conformación de clústeres o consorcios empresariales. A partir de ello, se podrá plantear propuestas que permitan generar una planificación estratégica, optimizar su capacidad competitiva y disposición para enfrentarse apropiadamente a una economía de libre mercado, el cual ha incrementado su competencia. Para el desarrollo de esta investigación, se planteó la siguiente pregunta general: ¿cómo afrontan el modelo de gestión de la capacidad competitiva de exportación las pymes de exportación de olivo en la región Tacna-Perú, en el periodo 2017, a través del conocimiento de las herramientas estratégicas de la Ruta Exportadora y de la conformación de clústeres o consorcios empresariales? Posteriormente, se definió el objetivo general: conocer de qué manera afrontan el modelo de gestión de la capacidad competitiva de exportación las pymes de exportación de olivo de la región Tacna - Perú, en el periodo 2017, a través del conocimiento de las herramientas estratégicas de la Ruta Exportadora y de la conformación de clústeres o consorcios empresariales. Se fundamenta en la aspiración de eficiencia y eficacia en su gestión empresarial y de incrementar sus oportunidades de exportación

Characterization of the Intrinsic Phospholipase A1 Activity of Bordetella pertussis Adenylate Cyclase Toxin

Adenylate cyclase toxin (ACT, CyaA) is one of the important virulence factors secreted by the whooping cough bacterium Bordetella pertussis, and it is essential for the colonization of the human respiratory tract by this bacterium. Cytotoxicity by ACT results from the synergy between toxin's two main activities, production of supraphysiological cAMP levels by its N-terminal adenylate cyclase domain (AC domain), and cell membrane permeabilization, induced by its C-terminal pore-forming domain (hemolysin domain), which debilitate the host defenses. In a previous study we discovered that purified ACT is endowed with intrinsic phospholipase A1 (PLA) activity and that Ser in position 606 of the ACT polypeptide is a catalytic site for such hydrolytic activity, as part of G-X-S-X-G catalytic motif. Recently these findings and our conclusions have been directly questioned by other authors who claim that ACT-PLA activity does not exist. Here we provide new data on ACT phospholipase A1 characteristics. Based on our results we reaffirm our previous conclusions that ACT is endowed with PLA activity; that our purified ACT preparations are devoid of any impurity with phospholipase A activity; that ACT-S606A is a PLA-inactive mutant and thus, that Ser606 is a catalytic site for the toxin hydrolytic activity on phospholipids, and that ACT-PLA activity is involved in AC translocation.This study was supported by grants from the Basque Government (Grupos Consolidados IT849) and grant from the Spanish Ministerio de Economia y Competitividad (BFU2017-82758-P (AEI/FEDER, UE) to H.O

Marine applications of the fast marching method

Path planning is general problem of mobile robots, which has special characteristics when applied to marine applications. In addition to avoid colliding with obstacles, in marine scenarios, environment conditions such as water currents or wind need to be taken into account in the path planning process. In this paper, several solutions based on the Fast Marching Method are proposed. The basic method focus on collision avoidance and optimal planning and, later on, using the same underlying method, the influence of marine currents in the optimal path planning is detailed. Finally, the application of these methods to consider marine robot formations is presented.The research leading to these results has received funding from HEROITEA-Sistema Inteligente Heterogéneo Multirobot para la Asistencia de Personas Mayores-RTI2018-095599-BC21 and from RoboCity2030-DIH-CM, Madrid Robotics Digital Innovation Hub, S2018/NMT-4331), funded by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EU

Using the input-output approach to measure participation in GVCs : the case of Costa Rica

In order to illustrate how the input-output approach can be used to explore various aspects of a country\u27s participation in GVCs, this paper applies indicators derived from the concept of trade in value-added (TiVA) to the case of Costa Rica. We intend to provide developing countries that seek to foster GVC-driven structural transformation with an example that demonstrates an effective way to measure progress. The analysis presented in this paper makes use of an International Input-Output Table (IIOT) that was constructed by including Costa Rica\u27s first Input-Output Table (IOT) into an existing IIOT. The TiVA indicator has been used to compare and contrast import flows, export flows and bilateral trade balances in terms of gross trade and trade in value-added. The country\u27s comparative advantage is discussed based on a TiVA-related indicator of revealed comparative advantage. The paper also decomposes the domestic content of value added in each sector and measures the degree of fragmentation in the value chains in which Costa Rica participates, highlighting the partner countries that add the most value

Membrane Repair Mechanisms against Permeabilization by Pore-Forming Toxins

Permeabilization of the plasma membrane represents an important threat for any cell, since it compromises its viability by disrupting cell homeostasis. Numerous pathogenic bacteria produce pore-forming toxins that break plasma membrane integrity and cause cell death by colloid-osmotic lysis. Eukaryotic cells, in turn, have developed different ways to cope with the effects of such membrane piercing. Here, we provide a short overview of the general mechanisms currently proposed for plasma membrane repair, focusing more specifically on the cellular responses to membrane permeabilization by pore-forming toxins and presenting new data on the effects and cellular responses to the permeabilization by an RTX (repeats in toxin) toxin, the adenylate cyclase toxin-hemolysin secreted by the whooping cough bacterium Bordetella pertussis, which we have studied in the laboratory.This study was supported by grants from the Basque Government (Grupos Consolidados IT849-13) and grant from the Spanish Ministerio de Economia y Competitividad (BFU2017-82758-PAEI/FEDER, UE)

Fast marching subjected to a vector field-path planning method for mars rovers

Path planning is an essential tool for the robots that explore the surface of Mars or other celestial bodies such as dwarf planets, asteroids, or moons. These vehicles require expert and intelligent systems to adopt the best decisions in order to survive in a hostile environment. The planning module has to take into account multiple factors such as the obstacles, the slope of the terrain, the surface roughness, the type of ground (presence of sand), or the information uncertainty. This paper presents a path planning system for rovers based on an improved version of the Fast Marching (FM) method. Scalar and vectorial properties are considered when computing the potential field which is the basis of the proposed technique. Each position in the map of the environment has a cost value (potential) that is used to include different types of variables. The scalar properties can be introduced in a component of the cost function that can represent characteristics such as difficulty, slowness, viscosity, refraction index, or incertitude. The cost value can be computed in different ways depending on the information extracted from the surface and the sensor data of the rover. In this paper, the surface roughness, the slope of the terrain, and the changes in height have been chosen according to the available information. When the robot is navigating sandy terrain with a certain slope, there is a landslide that has to be considered and corrected in the path calculation. This landslide is similar to a lateral current or vector field in the direction of the negative gradient of the surface. Our technique is able to compensate this vector field by introducing the influence of this variable in the cost function. Because of this modification, the new method has been called Fast Marching (subjected to a) vector field (FMVF). Different experiments have been carried out in simulated and real maps to test the method performance.Publicad

An anisotropic fast marching method applied to path planning for Mars rovers

This paper presents the application of the Anisotropic Fast Marching Method to the path planning problem of mobile robots moving in outdoors environments, such as Mars. Considering that at any point on a 3D surface there are two main slopes: the maximum, which is the slope of the gradient, and the minimum, the height map of a terrain can be considered as a tensor filed. Using the Anisotropic Fast Marching Method, the resulting trajectory of the path planning takes the tensor field into account so that the slopes in the trajectory are minimized. Numerical simulations are presented to show the advantage of this method over its isotropic version. Besides, the influence of the anisotropic index and the traversability of the resultant paths are analyzed.This work was supported in part by the projects: "RoboCity2030-III-CM project (Robótica aplicada a la mejora de la calidad de vida de los ciudadanos. fase III; S2013/MIT-2748), in part by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EU" and in part by "Investigación para la mejora competitiva del ciclo de perforación y voladura en minería y obras subterráneas, mediante la concepción de nuevas técnicas de ingeniería, explosivos, prototipos y herramientas avanzadas (TUÑEL)"