Remasking of Candida albicans β-Glucan in Response to Environmental pH Is Regulated by Quorum Sensing

Candida albicans is a commensal yeast of the human gut which is tolerated by the immune system but has the potential to become an opportunistic pathogen. One way in which C. albicans achieves this duality is through concealing or exposing cell wall pathogen-associated molecular patterns (PAMPs) in response to host-derived environment cues (pH, hypoxia, and lactate). This cell wall remodeling allows C. albicans to evade or hyperactivate the host’s innate immune responses, leading to disease. Previously, we showed that adaptation of C. albicans to acidic environments, conditions encountered during colonization of the female reproductive tract, induces significant cell wall remodeling resulting in the exposure of two key fungal PAMPs (β-glucan and chitin). Here, we report that this pH-dependent cell wall remodeling is time dependent, with the initial change in pH driving cell wall unmasking, which is then remasked at later time points. Remasking of β-glucan was mediated via the cell density-dependent fungal quorum sensing molecule farnesol, while chitin remasking was mediated via a small, heat-stable, nonproteinaceous secreted molecule(s). Transcript profiling identified a core set of 42 genes significantly regulated by pH over time and identified the transcription factor Efg1 as a regulator of chitin exposure through regulation of CHT2. This dynamic cell wall remodeling influenced innate immune recognition of C. albicans, suggesting that during infection, C. albicans can manipulate the host innate immune responses

An Applied Study on Social Equity Related Impacts of a Projected LEZ (Low Emission Zone) in the French City of Grenoble

International audienc

An Applied Study on Social Equity Related Impacts of a Projected LEZ (Low Emission Zone) in the French City of Grenoble

International audienc

Distribution spatio temporelle des équipements urbains de l'agglomération grenobloise

International audienceRESUME. Nous proposons une méthodologie développée pour collecter les horaires d'ouverture et de fermeture des équipements urbains des 26 communes de l'agglomération grenobloise. S'inscrivant dans le cadre du projet de recherche MIRO², la construction de cette base de données constitue un préalable à l'élaboration d'un modèle de simulation de la mobilité quotidienne intra-urbaine des habitants. Ce modèle tient compte du programme d'activités des habitants et des équipements accessibles spatialement et temporellement). Afin de caractériser les équipements, diverses méthodes ont été déployées pour collecter les informations sur les services et commerces, les entreprises, les équipements publics. L'article présente la méthodologie de géocodage, d'échantillonnage, d'enquête, de généralisation et propose un outil de géovisualisation des densités mouvantes d'équipements. ABSTRACT. We propose a methodology to collect the opening and closing hours of urban facilities of 26 towns of Grenoble urban area. As part of the MIRO² project, the construction of this database is a preliminary step to develop a model to simulate the intra-urban daily mobility of people. This model takes into account the program of activities of people and the spatial and temporal accessibility of equipment. Various methods have been developed to collect information on the facilities (services and shop, businesses and public facilities). The paper presents the methodology of geocoding, sampling, survey, generalization and provides a geovisualizing tool to explore moving equipment densities. MOTS-CLES : base de données ; approche spatiotemporelle ; équipements urbains ; géovisualisation ; Grenoble