scholarly journals Bacterial “Conversations” and Pattern Formation

2017 ◽  
Author(s):  
Sarangam Majumdar ◽  
Sisir Roy ◽  
Rodolfo Llinas
Keyword(s):  
Pattern Formation ◽  
Quorum Sensing ◽  
Burgers Equation ◽  
Water Movement ◽  
Reaction Diffusion ◽  
Dynamical Behaviour ◽  
Signal Molecules ◽  
Extracellular Milieu ◽  
Long Time ◽  
Coordinated Water

AbstractIt has long been recognized that certain bacterial groups exhibit cooperative behavioral patterns. Bacteria accomplish such communication via exchange of extracellular signaling molecules called pheromones(autoinducer or quorum sensing molecules). As the bacterial culture grows, signal molecules are released into extracellular milieu accumulate, changing water fluidity. Under such threshold conditions swimming bacterial suspensions impose a coordinated water movement on a length scale of the order 10 to 100 micrometers compared with a bacterial size of the order of 3 micrometers.Here, we investigate the non-local hydrodynamics of the quorum state and pattern formation using forced Burgers equation with Kwak transformation. Such approach resulted in the conversion of the Burgers equation paradigm into a reaction-diffusion system. The examination of the dynamics of the quorum sensing system, both analytically as well as numerically result in similar long-time dynamical behaviour.

scholarly journals Analyzing the dynamics of the forced Burgers equation

2000 ◽  
Vol 13 (3) ◽  
pp. 269-285 ◽  
Author(s):  
Nejib Smaoui
Keyword(s):  
Burgers Equation ◽  
Dynamical Behavior ◽  
Reaction Diffusion ◽  
Reaction Diffusion Equations ◽  
Diffusion Equations ◽  
Navier Stokes ◽  
Inertial Manifold ◽  
Navier Stokes Equation ◽  
Time Dynamics ◽  
Long Time

We study numerically the long-time dynamics of a system of reaction-diffusion equations that arise from the viscous forced Burgers equation (ut+uux−vuxx=F). A nonlinear transformation introduced by Kwak is used to embed the scalar Burgers equation into a system of reaction diffusion equations. The Kwak transformation is used to determine the existence of an inertial manifold for the 2-D Navier-Stokes equation. We show analytically as well as numerically that the two systems have a similar, long-time dynamical, behavior for large viscosity v.

scholarly journals A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution

2020 ◽  
Vol 74 (1) ◽  
pp. 587-606 ◽  
Author(s):  
Nitzan Aframian ◽  
Avigdor Eldar
Keyword(s):  
Quorum Sensing ◽  
Social Interactions ◽  
Signal Molecules ◽  
Allelic Polymorphism ◽  
Dependent Manner ◽  
Tower Of Babel ◽  
Cognate Receptor ◽  
Wide Range ◽  
Family Code ◽  
Bacterial Groups

Quorum sensing is a process in which bacteria secrete and sense a diffusible molecule, thereby enabling bacterial groups to coordinate their behavior in a density-dependent manner. Quorum sensing has evolved multiple times independently, utilizing different molecular pathways and signaling molecules. A common theme among many quorum-sensing families is their wide range of signaling diversity—different variants within a family code for different signal molecules with a cognate receptor specific to each variant. This pattern of vast allelic polymorphism raises several questions—How do different signaling variants interact with one another? How is this diversity maintained? And how did it come to exist in the first place? Here we argue that social interactions between signaling variants can explain the emergence and persistence of signaling diversity throughout evolution. Finally, we extend the discussion to include cases where multiple diverse systems work in concert in a single bacterium.

scholarly journals Peptide signaling without feedback in signal production operates as a true quorum sensing communication system in Bacillus subtilis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Iztok Dogsa ◽  
Mihael Spacapan ◽  
Anna Dragoš ◽  
Tjaša Danevčič ◽  
Žiga Pandur ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Quorum Sensing ◽  
Cell Density ◽  
Communication System ◽  
Communication Systems ◽  
Feedback Loop ◽  
Signal Molecules ◽  
Specific Cell ◽  
Sharp Transition

AbstractBacterial quorum sensing (QS) is based on signal molecules (SM), which increase in concentration with cell density. At critical SM concentration, a variety of adaptive genes sharply change their expression from basic level to maximum level. In general, this sharp transition, a hallmark of true QS, requires an SM dependent positive feedback loop, where SM enhances its own production. Some communication systems, like the peptide SM-based ComQXPA communication system of Bacillus subtilis, do not have this feedback loop and we do not understand how and if the sharp transition in gene expression is achieved. Based on experiments and mathematical modeling, we observed that the SM peptide ComX encodes the information about cell density, specific cell growth rate, and even oxygen concentration, which ensure power-law increase in SM production. This enables together with the cooperative response to SM (ComX) a sharp transition in gene expression level and this without the SM dependent feedback loop. Due to its ultra-sensitive nature, the ComQXPA can operate at SM concentrations that are 100–1000 times lower than typically found in other QS systems, thereby substantially reducing the total metabolic cost of otherwise expensive ComX peptide.

Role of Nuclei in Liesegang Pattern Formation: Insights from Experiment and Reaction-Diffusion Simulation

2018 ◽  
Vol 122 (6) ◽  
pp. 3669-3676 ◽  
Author(s):  
Masaki Itatani ◽  
Qing Fang ◽  
Kei Unoura ◽  
Hideki Nabika
Keyword(s):  
Pattern Formation ◽  
Reaction Diffusion ◽  
Diffusion Simulation
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