The bacterium Pseudomonas aeruginosa is an opportunistic human pathogen that uses a quorum sensing signal cascade to activate expression of dozens of genes when sufficient population densities have been reached. Quorum sensing controls production of several key virulence factors, including secreted proteases such as elastase. Cooperating groups of bacteria growing on protein are susceptible to ...

Membrane biofouling remains a severe problem to be addressed in wastewater treatment systems affecting reactor performance and economy. The finding that many wastewater bacteria rely on N-acyl homoserine lactone-mediated quorum sensing to synchronize their activities essential for biofilm formations; the quenching bacterial quorum sensing suggests a promising approach for control of membrane bi...

Quorum sensing is a type of cell to cell communication used to coordinate behavior in groups based on population density. We present a mathematical model of this phenomenon in bacterial biofilms, consisting of a nonlinear diffusion reaction system. The model includes production and spatial spreading of biomass, conversion of down-regulated biomass into up-regulated biomass as a consequence of t...

Most Proteobacteria produce N-acylhomoserine lactones for bacterial cell-to-cell communication, a process called quorum sensing. Interference of quorum sensing, commonly known as quorum quenching, represents an important way to control quorum sensing. This work reports the isolation of quorum quenching bacterium strain 2WS8 from Malaysia tropical wetland water (2°11'8"N, 102°15'2"E, in 2007) by...

Quorum systems are commonly used to maintain the consistency of replicated data in a distributed system. Much research has been devoted to developing quorum systems with good theoretical properties, such as fault tolerance and high availability. However, even given a theoretically good quorum system, it is not obvious how to efficiently deploy such a system in a real network. This paper introdu...

Bacteria communicate through small diffusible molecules in a process known as quorum sensing. Quorum-sensing inhibitors are compounds which interfere with this, providing a potential treatment for infections associated with bacterial biofilms. We present an individual-based computational model for a developing biofilm. Cells are aggregated into particles for computational efficiency, but the qu...

2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 2/36 Motivation 2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 3/36 Immune system Leukocytes (white blood cells) circulate in the blood Leukocytes are produced in the b...

Bacterial phenotypes, such as biofilm formation, antibiotic resistance and virulence expression, are associated with quorum sensing. Quorum sensing is a density-dependent regulatory system of gene expression controlled by specific signal molecules, such as N-acyl homoserine lactones (AHLs), produced and released by bacteria. This study reports the development of linear polymers capable to atten...

Replicated services accessed via quorums enable each access to be performed at only a subset (quorum) of the servers and achieve consistency across accesses by requiring any two quorums to intersect. Recently, b-masking quorum systems, whose intersections contain at least 2b+1 servers, have been proposed to construct replicated services tolerant of b-arbitrary (Byzantine) server failures. In th...

We study direct democracy with population uncertainty. Voters’ participation is often among the desiderata by the election designer. A participation quorum is a threshold on the fraction of participating voters below which the status quo is kept. We show that participation quorums produce incentive for partisans of the status quo to abstain, with the consequence that the status quo may be kept ...