Because the control of gene expression by autoinducers is cell-density-dependent, this phenomenon has been called quorum sensing. Quorum sensing controls virulence gene expression in numerous micro-organisms. In some cases, this phenomenon has proven relevant for bacterial virulence in vivo. In this article, we provide a few examples to illustrate how quorum sensing can act to control bacterial virulence in a multitude of ways. Several classes of autoinducers have been described to date and ... Quorum sensing is a process by which bacteria communicate with one another by secreting extracellular signaling molecules termed autoinducers. In V. cholerae, expression of virulence is negatively regulated by quorum sensing (Zhu et al., 2002). Two autoinducer systems function in V. cholerae: CAI-1 and autoinducer 2 (AI-2). We show that in mixed infections of the bacterium Pseudomonas aeruginosa, containing quorum-sensing bacteria and mutants that do not respond to signal, virulence in an animal (mouse) model is reduced relative to that of an infection containing no mutants. We show that this is because mutants act as cheats, exploiting the cooperative production of signal and virulence factors by others, and hence increase in frequency. This supports the idea that the invasion of QS mutants in ... Bacteria are highly interactive and possess an extraordinary repertoire of intercellular communication and social behaviors, including quorum sensing (QS). QS has been studied in detail at the molecular level, so mechanistic details are well understood in many species and are often involved in virulence. Quorum sensing (QS) is a bacterial cell–cell communication process that involves the production, detection, and response to extracellular signaling molecules called autoinducers (AIs). AIs accumulate in the environment as the bacterial population density increases, and bacteria monitor this information to track changes in their cell numbers and collectively alter gene expression. QS controls genes that direct activities that are beneficial when performed by groups of bacteria acting in ... Quorum sensing is a process of cell–cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly. This process enables bacteria to express energetically expensive processes as a collective only when the impact of those processes on the environment or on a host will be maximized. Because the control of gene expression by autoinducers is cell-density-dependent, this phenomenon has been called quorum sensing. Quorum sensing controls virulence gene expression in numerous... As well as their importance to nutrition, fatty acids (FA) represent a unique group of quorum sensing chemicals that modulate the behavior of bacterial population in virulence. However, the way in which full-length, membrane-bound receptors biochemically detect FA remains unclear. Here, we provide genetic, enzymological and biophysical evidences to demonstrate that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, a medium-chain FA diffusible signal factor (DSF) binds ... In vitro experiments suggest that autoinducer molecules are signals used to coordinate cooperative behaviors and that this process of quorum sensing (QS) can be exploited by individual cells that avoid the cost of either producing or responding to signal [6, 7]. However, whether QS is an exploitable social trait in vivo, and the implications for the evolution of virulence [5, 8–10], remains untested. Abstract Quorum sensing is the regulation of gene expression in response to fluctuations in cell-population density. Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density. The detection of a minimal threshold stimulatory concentration of an autoinducer leads to an alteration in gene expression. Gram-positive and Gram-negative bacteria use quorum sensing communication circuits to regulate a ...
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