AIM This review intends to provide a brief overview regarding quorum sensing among bacteria in biofilms and also attempts to throw light on the new research focusing on interference with the quorum sensing. BACKGROUND Dental plaque is an example of microbial biofilm leading to periodontal disease and dental caries. Quorum sensing is widely employed by a variety of gram-positive and gram-negat...

Biofilms are microorganisms, where bacteria are embedded in networks formed by bacteria-produced expopolysacharrides, also known as extracellular polymeric substances (EPS). Bacteria in biofilms communicate and cooperate with each other by sensing the density of signalling molecules that bacteria excrete. This phenomenon is known as quorum sensing (QS). In this paper, we develop a hydrodynamic ...

Signaling mechanisms that govern physiological and morphological responses to changes in cell density are common in bacteria. Quorum sensing, as such signal transduction processes are called, involves the production of, release of, and response to hormone-like molecules (autoinducers) that accumulate in the external environment as the cell population grows. Quorum sensing is found in a wide var...

Quorum sensing is a mechanism of cell-to-cell communication that allows bacteria to coordinately regulate gene expression in response to changes in cell-population density. At the core of the Vibrio cholerae quorum-sensing signal transduction pathway reside four homologous small RNAs (sRNAs), named the quorum regulatory RNAs 1-4 (Qrr1-4). The four Qrr sRNAs are functionally redundant. That is, ...

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...

Over the past decade, work on quorum systems in non-traditional scenarios has facilitated a number of advances in the field of distributed systems. This chapter surveys a selection of these results including: Byzantine quorum systems that are suitable for use when parts of the system cannot be trusted; algorithms for the deployment of quorum systems on wide area networks so as to allow for effi...

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...

Data replication is a central mechanism for the engineering of fault-tolerant distributed systems, and is used in the realization of most cloud computing services. This paper explores the use of Coloured Petri Nets (CPNs) for model-based testing of quorum-based distributed systems. We have used model-based testing to validate a distributed storage implemented using the Go language and the Gorum...

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...

In a match-making system, sources (producers) advertise generated data without any particular destination in mind. Destinations (consumers) are determined based on their interests (via subscriptions) in receiving the produced data. Advertisements and subscriptions are matched by the underlying network service. We propose to facilitate match-making capability in ad hoc and sensor networks by ada...