Wolbachia Age-Sex-Specific Density in Aedes albopictus: A Host Evolutionary Response to Cytoplasmic Incompatibility?

Wolbachia bacteria have invaded many arthropod species by inducing Cytoplasmic Incompatibility (CI). These symbionts represent fascinating objects of study for evolutionary biologists, but also powerful potential biocontrol agents. Here, we assess the density dynamics of Wolbachia infections in males and females of the mosquito Aedes albopitcus, an important vector of human pathogens, and interpret the results within an evolutionary framework.Wolbachia densities were measured in natural populations and in age controlled mosquitoes using quantitative PCR. We show that the density dynamics of the wAlbA Wolbachia strain infecting Aedes albopictus drastically differ between males and females, with a very rapid decay of infection in males only.Theory predicts that Wolbachia and its hosts should cooperate to improve the transmission of infection to offspring, because only infected eggs are protected from the effects of CI. However, incompatible matings effectively lower the fertility of infected males, so that selection acting on the host genome should tend to reduce the expression of CI in males, for example, by reducing infection density in males before sexual maturation. The rapid decay of one Wolbachia infection in Aedes albopictus males, but not in females, is consistent with this prediction. We suggest that the commonly observed reduction in CI intensity with male age reflects a similar evolutionary process. Our results also highlight the importance of monitoring infection density dynamics in both males and females to assess the efficiency of Wolbachia-based control strategies

Resistive switching and charge transport mechanisms in ITO/ZnO/p-Si devices

[EN] The resistive switching properties of ITO/ZnO/p-Si devices have been studied, which present well-defined resistance states with more than five orders of magnitude difference in current. Both the high resistance state (HRS) and the low resistance state (LRS) were induced by either sweeping or pulsing the voltage, observing some differences in the HRS. Finally, the charge transport mechanisms dominating the pristine, HRS, and LRS states have been analyzed in depth, and the obtained structural parameters suggest a partial re-oxidation of the conductive nanofilaments and a reduction of the effective conductive area.This work was financially supported by the Spanish Ministry of Economy and Competitiveness (Project Nos. TEC2012-38540-C02-01 and TEC2016-76849-C2-1-R). O.B. also acknowledges the subprogram "Ayudas para Contratos Predoctorales para la Formacion de Doctores" of the Spanish Ministry of Economy and Competitiveness for economical support. 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Concurso Bienal 1975 - 1976

Contenido Casas entre mediaderos Simón Bolivar, Santiago - Conjunto Habitacional Siete Hermanas Viña del Mar - Industria Nacional del Cemento "Inacesa" Antofagasta - Central de Adquisiciones Automotrices Santiago - Estudio preinversional de vivienda y desarrollo urbano para Iquique "Cedur" - Planeamiento del equipo escolar "Centro Metropolitano" de Concepción - Sociedad de stablecimientos Educacionales - Nuede Arquitectura y Urbanismo de la Universidad de Chile - Vivienda popular en Santiago de Chile - Elemento estructural Feria Municipal de la Vega Santiago - Hotel Internacional Rocas de Santo Domingo

Acquisition of Complement Inhibitor Serine Protease Factor I and Its Cofactors C4b-Binding Protein and Factor H by Prevotella intermedia

Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP) and Factor H (FH). Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with 125I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases

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