It is postulated that in addition to cell density, other factors such as the dimensions and diffusional characteristics of the environment could influence quorum sensing (QS) and induction of genetic reprogramming. Modeling studies predict that QS may operate at the level of a single cell, but, owing to experimental challenges, the potential benefits of QS by individual cells remain virtually u...

We study direct democracy with population uncertainty. Voters’ participation is often among the desiderata by the election designer. We show that with a participation quorum, i.e. a threshold on the fraction of participating voters below which the status quo is kept, the status quo may be kept in situations where the planner would prefer the reform, or the reform is passed when the planner pref...

Ensuring the consistency and the availability of replicated data in highly mobile ad hoc networks is a challenging task because of the lack of a backbone infrastructure. Previous work provides strong data guarantees by limiting the motion and the speed of the mobile nodes during the entire system lifetime, and by relying on assumptions that are not realistic for most mobile applications. We pro...

We investigate the dynamics of a synthetic genetic repressilator with quorum sensing feedback. In a basic genetic ring oscillator network in which three genes inhibit each other in unidirectional manner, an additional quorum sensing feedback loop stimulates the activity of a chosen gene providing competition between inhibitory and stimulatory activities localized in that gene. Numerical simulat...

The las quorum-sensing system of Pseudomonas aeruginosa controls the expression of elastase and rhamnolipid. We report that starvation can select a mutant producing these virulence factors in spite of a lasR deletion. Expression of the autoinducer synthase gene rhlI was increased in this suppressor mutant, suggesting compensation by the rhl system. These data show that P. aeruginosa can restore...

We describe here a role for quorum sensing in the detachment, or sloughing, of Serratia marcescens filamentous biofilms, and we show that nutrient conditions affect the biofilm morphotype. Under reduced carbon or nitrogen conditions, S. marcescens formed a classical biofilm consisting of microcolonies. The filamentous biofilm could be converted to a microcolony-type biofilm by switching the med...

While a functional quorum sensing system has been identified in the acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 23270(T) and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in A. ferrooxidans (T), the transcriptome of this organism in conditions ...

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...

Providing shared-memory abstraction in messagepassing systems often simplifies the development of distributed algorithms and allows for the reuse of sharedmemory algorithms in the message-passing setting. A robust emulation of atomic single-writer/multi-reader registers in message-passing systems was developed by Attiya, Bar-Noy and Dolev (1995). This emulation was extended by Lynch and Shvarts...

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...