In a process termed quorum sensing, bacteria use diffusible chemical signals to coordinate cell density-dependent gene expression. In the human pathogen Pseudomonas aeruginosa, quorum sensing controls hundreds of genes, many of which encode extracellular virulence factors. Quorum sensing is required for P. aeruginosa virulence in animal models. Curiously, quorum sensing-deficient variants, most...

Quorum systems satisfying the rotation closure property can be used to realize asynchronous power-saving algorithms for mobile ad hoc networks. The FPP, grid, cyclic, torus and e-torus quorum systems can provide the algorithms with the lowest or near lowest active ratios since they have the optimal or near optimal quorum sizes. The algorithms guarantee that a node can sense the status of every ...

In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing), others are interrupting the communication (quorum quenching), thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely ...

We propose a simple model to compute the probability of success under a quorum sensing strategy. We show that a quorum sensing strategy has a higher probability of success than an individualistic strategy when, for instance, the probability of success for a single individual is low and the cost of building a quorum is not too high. On the other hand if the cost of building a quorum is too high ...

In distributed systems it is often necessary to provide coordination among the multiple concurrent processes. Quorum systems provide a decentralized approach to provide such coordination that is resilient to node and communication link failures. Quorum systems are highly available and may be used to balance the load among the elements of the system. In this paper, we propose a modification to t...

quorum sensing controls the luminescence of vibrio fischeri through the transcriptional activator luxr and the specific autoinducer signal produced by luxi. amino acid sequences of these two genes were analyzed using bioinformatics tools. luxi consists of 193 amino acids and appears to contain five α-helices and six ß-sheets when analyzed by sspro8. luxi belongs to the autoinducer synthetase fa...

Quorum sensing allows bacteria to sense and respond to changes in population density. Acyl-homoserine lactones serve as quorum-sensing signals for many Proteobacteria, and acyl-homoserine lactone signaling is known to control cooperative activities. Quorum-controlled activities vary from one species to another. Quorum-sensing controls a constellation of genes in the opportunistic pathogen Pseud...

In the present study, variation among different bacterial strains was observed in the plaques of tobacco chewers (TC) as compared to those from normal persons (non tobacco chewers) (NTC). Bacterial strain J1 (dominant in the plaques of NTC) did not initiate the process of adhesion (biofilm formation) until it appeared to have reached a required population density necessary for the production of...

We explore applications of quorum systems to the problem of tracking locations of mobile users in mobile ad hoc networks (MANETs). The location tracking system uses biquorum systems, a generalization of traditional quorum systems. We performed extensive simulations of the location tracking system. The simulation results show that our strict biquorum implementation has better performance than th...