Search results for "Interactions"

Cell Lines: A Tool for In Vitro Drug Metabolism Studies

2008

Primary cultured hepatocytes are a valuable in vitro model for drug metabolism studies. However, their widespread use is greatly hindered by the scarcity of suitable human liver samples. Moreover, the well-known in vitro phenotypic instability of hepatocytes, the irregular availability of fresh human liver for cell harvesting purposes, and the high batch-to-batch functional variability of hepatocyte preparations obtained from different human liver donors, seriously complicate their use in routine testing. To overcome these limitations, different cell line models have been proposed for drug metabolism screening. Human liver-derived cell lines would be ideal models for this purpose given thei…

Echovirus 1 Entry into Polarized Caco-2 Cells Depends on Dynamin, Cholesterol, and Cellular Factors Associated with Macropinocytosis

2013

ABSTRACT Enteroviruses invade their hosts by crossing the intestinal epithelium. We have examined the mechanism by which echovirus 1 (EV1) enters polarized intestinal epithelial cells (Caco-2). Virus binds to VLA-2 on the apical cell surface and moves rapidly to early endosomes. Using inhibitory drugs, dominant negative mutants, and small interfering RNAs (siRNAs) to block specific endocytic pathways, we found that virus entry requires dynamin GTPase and membrane cholesterol but is independent of both clathrin- and caveolin-mediated endocytosis. Instead, infection requires factors commonly associated with macropinocytosis, including amiloride-sensitive Na + /H + exchange, protein kinase C, …

Formation et médiation en r(é)volution numérique : enjeux communicationnels de l'intégration du digital learning dans les centres de contact

2018

This thesis is part of the information and communication sciences, under the nail of evolution, of the media. Information and communication technologies (ICTs) have invested in our everyday life, globalized digitization and connected objects have considerably modified the practices and uses in the training services of companies, especially in terms of interpersonal communication and digitized pedagogical relations. This work of thesis aims to accompany the trainers of the contact centers on the processes, the conditions of success and the stakes of the integration of the e-learning. By analyzing in what ways new training practices, notably via online platforms, generalized digitization have…

Physicochemical and perceptual interactions between composition/texture, taste and aroma: A way to enhance saltiness in foods

2009

Diplôme : Ph. D.; Excessive salt in the human diet is a major risk factor for hypertension and cardiovascular diseases. So, the World Health Organisation (WHO) advocates sodium reduction of foods as a cost-effective strategy to improve public health. Because of important functionalities of salt (NaCl) – salty taste and flavour enhancement, solutions are being sought to lower the salt content of processed foods without altering their taste. In this PhD work, the approach proposed was to use sensory interactions between the senses, especially composition/texture – saltiness interactions (i) and aroma-saltiness interactions (ii). The first part of this work aimed to investigate food compositio…

Within-host evolution decreases virulence in an opportunistic bacterial pathogen

2015

Abstract Background Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for growth and survival outside versus within the host, rather than transmission potential, shape the evolution of virulence in opportunists. We tested the role of within-host selection in evolution of virulence by letting a pathogen Serratia marcescens db11 sequent…

Criteria for species determination in the 'revolutum' group of Echinostoma.

2004

Slow Infection due to Lowering the Amount of Intact versus Empty Particles Is a Characteristic Feature of Coxsackievirus B5 Dictated by the Structura…

2019

Enterovirus B species typically cause a rapid cytolytic infection leading to efficient release of progeny viruses. However, they are also capable of persistent infections in tissues, which are suggested to contribute to severe chronic states such as myocardial inflammation and type 1 diabetes. In order to understand the factors contributing to differential infection strategies, we constructed a chimera by combining the capsid proteins from fast-cytolysis-causing echovirus 1 (EV1) with nonstructural proteins from coxsackievirus B5 (CVB5), which shows persistent infection in RD cells. The results showed that the chimera behaved similarly to parental EV1, leading to efficient cytolysis in both…

Coxsackievirus A9 Infects Cells via Nonacidic Multivesicular Bodies

2014

ABSTRACT Coxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae . According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, the structures utilized by the virus for internalization and uncoating are less well understood. We show here, based on electron microscopy, that CVA9 is found in multivesicular structures 2 h postinfection (p.i.). A neutral red labeling assay revealed that uncoating occurs mainly around 2 h p.i., while double-stranded RNA is found in the cytoplasm after 3 h p.i. The biogenesis of multivesicu…

Hydrophobic pocket targeting probes for enteroviruses

2015

Visualization and tracking of viruses without compromising their functionality is crucial in order to understand virus targeting to cells and tissues, and to understand the subsequent subcellular steps leading to virus uncoating and replication. Enteroviruses are important human pathogens causing a vast number of acute infections, and are also suggested to contribute to the development of chronic diseases like type I diabetes. Here, we demonstrate a novel method to target site-specifically the hydrophobic pocket of enteroviruses. A probe, a derivative of Pleconaril, was developed and conjugated to various labels that enabled the visualization of enteroviruses under light and electron micros…

Early entry events in Echovirus 30 infection

2020

Echovirus 30 (E30), a member of the enterovirus B species, is a major cause of viral meningitis, targeting children and adults alike. While it is a frequently isolated enterovirus and the cause of several outbreaks all over the world, surprisingly little is known regarding its entry and replication strategy within cells. In this study, we used E30 strain Bastianni (E30B) generated from an infectious cDNA clone in order to study early entry events during infection in human RD cells. E30B required the newly discovered Fc echovirus receptor (FcRn) for successful infection, but not the coxsackievirus and adenovirus receptor (CAR) or decay-accelerating factor (DAF), although an interaction with …