Search results for "QUORUM SENSING"
showing 10 items of 31 documents
N-acyl-homoserine-lactone quorum sensing in tomato phytopathogenic Pseudomonas spp. is involved in the regulation of lipodepsipeptide production
2012
Pseudomonas corrugata and Pseudomonas mediterranea are two closely related phytopathogenic bacteria both causal agents of tomato pith necrosis. P. corrugata produces phytotoxic and antimicrobial cationic lipodepsipeptides (LDPs) which are thought to act as major virulence factors. Previous studies have demonstrated that P. corrugata CFBP 5454 has an N-acyl homoserine lactone (AHL) quorum sensing (QS) system PcoI/PcoR and that LDP production occurs at high population densities. No molecular studies on virulence have thus far been reported for P. mediterranea. In this study, we show that P. mediterranea also produces LDPs as well as possessing an AHL-dependent QS system, designated PmeI/PmeR,…
Self-organization of active particles by quorum sensing rules
2018
Many microorganisms regulate their behaviour according to the density of neighbours. Such quorum sensing is important for the communication and organisation within bacterial populations. In contrast to living systems, where quorum sensing is determined by biochemical processes, the behaviour of synthetic active particles can be controlled by external fields. Accordingly they allow to investigate how variations of a density-dependent particle response affect their self-organisation. Here we experimentally and numerically demonstrate this concept using a suspension of light-activated active particles whose motility is individually controlled by an external feedback-loop, realised by a particl…
Robust dynamical pattern formation from a multifunctional minimal genetic circuit.
2010
Abstract Background A practical problem during the analysis of natural networks is their complexity, thus the use of synthetic circuits would allow to unveil the natural mechanisms of operation. Autocatalytic gene regulatory networks play an important role in shaping the development of multicellular organisms, whereas oscillatory circuits are used to control gene expression under variable environments such as the light-dark cycle. Results We propose a new mechanism to generate developmental patterns and oscillations using a minimal number of genes. For this, we design a synthetic gene circuit with an antagonistic self-regulation to study the spatio-temporal control of protein expression. He…
Communication and Autoinduction in the species Listeria monocytogenes
2014
International audience; In order to withstand changes in their environment, bacteria have evolved mechanisms to sense the surrounding environment, integrate these signals and adapt their physiology to thrive under fluctuating conditions. Among these mechanisms, the ability of bacteria to exchange information between cells has become a dynamic field of interest for microbiologists over the past four decades. First described by Nelson et al.,1 this phenomenon often referred as either cell-cell communication, Quorum Sensing and/or AutoInduction involves the synthesis of small signal molecules called autoinducers. These signal molecules may be sensed by the bacterial population in the vicinity …
Le système [i]agr[/i] de [i]Listeria monocytogenes[/i] et la croissance en biofilm : revisite des notions de communication, quorum sensing et auto-in…
2010
Communication orale, résumé; Parmi les mécanismes cellulaires qui participent à la mise en place des biofilms, l’échange de molécules de communication apparaît nécessaire chez de nombreux microorganismes. Listeria monocytogenes est une bactérie ubiquiste responsable de pathologies sévères chez des populations à risque (immunodéprimés, femmes enceintes, personnes âgées) en cas de consommation d’aliments contaminés. Nous avons récemment démontré que le système de communication agr est impliqué au cours de la croissance sessile de cette bactérie (Rieu et al., 2007). Par ailleurs, l’expression du système agr était hétérogène pendant la croissance en biofilm (Rieu et al., 2008) et localisée à sa…
Le système Agr de Listeria monocytogenes : revisite des notions de Quorum Sensing et auto-induction par cytométrie en flux
2011
National audience
Listeria monocytogenes agr system: Quorum sensing, or maybe not?
2010
International audience
Biofilm Related to Animal Health, Zoonosis and Food Transmitted Diseases: Alternative Targets for Antimicrobial Strategy?
2012
The biofilm is a complex community of microbial cells that are associated with a surface and enclosed in a self-produced biopolymer matrix. Such structured community is a response of bacteria to a signal system named quorum sensing (QS) constituted by inter-cell communication through the production of small molecules called autoinducers (AIs) that trigger a cascade of events in gene expression. When the concentration of the AIs molecules reach a certain threshold, the bacterial population acts as a single organism, collectively expressing virulence or biofilm forming genes. Gram-positive bacteria use modified oligopeptides as QS effectors molecules.
Quorum Sensing effects on Pseudomonas corrugata plant interaction and antagonistic activity
2010
Evidence of autoinduction heterogeneity via expression of the agr system of listeria monocytogenes at the single-cell level
2011
ABSTRACT To investigate if the primary function of the Agr system of Listeria monocytogenes is to monitor cell density, we followed Agr expression in batch cultures, in which the autoinducer concentration was uniform, and in biofilms. Expression was heterogeneous, suggesting that the primary function of Agr is not to monitor population density.