Quorum-sensing induced transitions between bistable steady-states for a cell-bulk ODE-PDE model with lux intracellular kinetics

2021 ◽  
Vol 84 (1-2) ◽  
Author(s):  
Wesley Ridgway ◽  
Michael J. Ward ◽  
Brian T. Wetton
Keyword(s):  
Quorum Sensing ◽  
Steady States ◽  
Pde Model ◽  
A Cell

scholarly journals PapRIV, a BV-2 microglial cell activating quorum sensing peptide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yorick Janssens ◽  
Nathan Debunne ◽  
Anton De Spiegeleer ◽  
Evelien Wynendaele ◽  
Marta Planas ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Model ◽  
Dependent Manner ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Gastro Intestinal Tract

AbstractQuorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.

scholarly journals Quorum Sensing: a Transcriptional Regulatory System Involved in the Pathogenicity of Burkholderia mallei

2004 ◽  
Vol 72 (11) ◽  
pp. 6589-6596 ◽  
Author(s):  
Ricky L. Ulrich ◽  
David DeShazer ◽  
Harry B. Hines ◽  
Jeffrey A. Jeddeloh
Keyword(s):  
Quorum Sensing ◽  
Virulence Factor ◽  
Regulatory System ◽  
In Silico Analysis ◽  
Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Wild Type ◽  
Transcriptional Regulatory ◽  
A Cell

ABSTRACT Numerous gram-negative bacterial pathogens regulate virulence factor expression by using a cell density mechanism termed quorum sensing (QS). An in silico analysis of the Burkholderia mallei ATCC 23344 genome revealed that it encodes at least two luxI and four luxR homologues. Using mass spectrometry, we showed that wild-type B. mallei produces the signaling molecules N-octanoyl-homoserine lactone and N-decanoyl-homoserine lactone. To determine if QS is involved in the virulence of B. mallei, we generated mutations in each putative luxIR homologue and tested the pathogenicities of the derivative strains in aerosol BALB/c mouse and intraperitoneal hamster models. Disruption of the B. mallei QS alleles, especially in RJ16 (bmaII) and RJ17 (bmaI3), which are luxI mutants, significantly reduced virulence, as indicated by the survival of mice who were aerosolized with 104 CFU (10 50% lethal doses [LD50s]). For the B. mallei transcriptional regulator mutants (luxR homologues), mutation of the bmaR5 allele resulted in the most pronounced decrease in virulence, with 100% of the challenged animals surviving a dose of 10 LD50s. Using a Syrian hamster intraperitoneal model of infection, we determined the LD50s for wild-type B. mallei and each QS mutant. An increase in the relative LD50 was found for RJ16 (bmaI1) (>967 CFU), RJ17 (bmaI3) (115 CFU), and RJ20 (bmaR5) (151 CFU) compared to wild-type B. mallei (<13 CFU). These findings demonstrate that B. mallei carries multiple luxIR homologues that either directly or indirectly regulate the biosynthesis of an essential virulence factor(s) that contributes to the pathogenicity of B. mallei in vivo.

scholarly journals Analysis of an HTLV/HIV dual infection model with diffusion

2021 ◽  
Vol 18 (6) ◽  
pp. 9430-9473
Author(s):  
A. M. Elaiw ◽  
◽  
N. H. AlShamrani ◽  
◽  
Keyword(s):  
Lyapunov Functions ◽  
Global Solutions ◽  
Dual Infection ◽  
Steady States ◽  
Infection Model ◽  
Well Posedness ◽  
Pde Model ◽  
Existence And Stability ◽  
Infected Cells ◽  
Theoretical Results

<abstract><p>In the literature, several HTLV-I and HIV single infections models with spatial dependence have been developed and analyzed. However, modeling HTLV/HIV dual infection with diffusion has not been studied. In this work we derive and investigate a PDE model that describes the dynamics of HTLV/HIV dual infection taking into account the mobility of viruses and cells. The model includes the effect of Cytotoxic T lymphocytes (CTLs) immunity. Although HTLV-I and HIV primarily target the same host, CD$ 4^{+} $T cells, via infected-to-cell (ITC) contact, however the HIV can also be transmitted through free-to-cell (FTC) contact. Moreover, HTLV-I has a vertical transmission through mitosis of active HTLV-infected cells. The well-posedness of solutions, including the existence of global solutions and the boundedness, is justified. We derive eight threshold parameters which govern the existence and stability of the eight steady states of the model. We study the global stability of all steady states based on the construction of suitable Lyapunov functions and usage of Lyapunov-LaSalle asymptotic stability theorem. Lastly, numerical simulations are carried out in order to verify the validity of our theoretical results.</p></abstract>

scholarly journals Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor inSalmonella entericaserovar Typhimurium

2018 ◽  
Vol 14 ◽  
pp. 2651-2664 ◽  
Author(s):  
Matthew J Styles ◽  
Helen E Blackwell
Keyword(s):  
Quorum Sensing ◽  
Small Molecules ◽  
Homoserine Lactone ◽  
Interspecies Interactions ◽  
Host Colonization ◽  
Serovar Typhimurium ◽  
Coordinate Group ◽  
A Cell ◽  
Production Host

Quorum sensing (QS) allows many common bacterial pathogens to coordinate group behaviors such as virulence factor production, host colonization, and biofilm formation at high population densities. This cell–cell signaling process is regulated byN-acyl L-homoserine lactone (AHL) signals, or autoinducers, and LuxR-type receptors in Gram-negative bacteria. SdiA is an orphan LuxR-type receptor found inEscherichia, Salmonella, Klebsiella, and Enterobactergenera that responds to AHL signals produced by other species and regulates genes involved in several aspects of host colonization. The inhibition of QS using non-native small molecules that target LuxR-type receptors offers a non-biocidal approach for studying, and potentially controlling, virulence in these bacteria. To date, few studies have characterized the features of AHLs and other small molecules capable of SdiA agonism, and no SdiA antagonists have been reported. Herein, we report the screening of a set of AHL analogs to both uncover agonists and antagonists of SdiA and to start to delineate structure–activity relationships (SARs) for SdiA:AHL interactions. Using a cell-based reporter of SdiA inSalmonella entericaserovar Typhimurium, several non-natural SdiA agonists and the first set of SdiA antagonists were identified and characterized. These compounds represent new chemical probes for exploring the mechanisms by which SdiA functions during infection and its role in interspecies interactions. Moreover, as SdiA is highly stable when produced in vitro, these compounds could advance fundamental studies of LuxR-type receptor:ligand interactions that engender both agonism and antagonism.

scholarly journals Targeting Quorum Sensing: High-Throughput Screening to Identify Novel LsrK Inhibitors

2019 ◽  
Vol 20 (12) ◽  
pp. 3112 ◽  
Author(s):  
Viviana Gatta ◽  
Polina Ilina ◽  
Alison Porter ◽  
Stuart McElroy ◽  
Päivi Tammela
Keyword(s):  
Quorum Sensing ◽  
High Throughput ◽  
High Throughput Screening ◽  
Enteric Bacteria ◽  
New Class ◽  
Bacterial Pathogenicity ◽  
Autoinducer 2 ◽  
A Cell ◽  
The Moment ◽  
Antivirulence Agents

Since quorum sensing (QS) is linked to the establishment of bacterial infection, its inactivation represents one of the newest strategies to fight bacterial pathogens. LsrK is a kinase playing a key role in the processing of autoinducer-2 (AI-2), a quorum-sensing mediator in gut enteric bacteria. Inhibition of LsrK might thus impair the quorum-sensing cascade and consequently reduce bacterial pathogenicity. Aiming for the development of a target-based assay for the discovery of LsrK inhibitors, we evaluated different assay set-ups based on ATP detection and optimized an automation-compatible method for the high-throughput screening of chemical libraries. The assay was then used to perform the screening of a 2000-compound library, which provided 12 active compounds with an IC50 ≤ 10 µM confirming the effectiveness and sensitivity of our assay. Follow-up studies on the positive hits led to the identification of two compounds, harpagoside and rosolic acid, active in a cell-based AI-2 QS interference assay, which are at the moment the most promising candidates for the development of a new class of antivirulence agents based on LsrK inhibition.

scholarly journals Erratum: A cell-cell communication signal integrates quorum sensing and stress response

2013 ◽  
Vol 9 (6) ◽  
pp. 406-406
Author(s):  
Jasmine Lee ◽  
Jien Wu ◽  
Yinyue Deng ◽  
Jing Wang ◽  
Chao Wang ◽  
...  
Keyword(s):  
Stress Response ◽  
Quorum Sensing ◽  
Cell Communication ◽  
Communication Signal ◽  
A Cell ◽  
Cell Cell

scholarly journals Development and Comparison of Whole-Cell Assay Systems for Quorum-Sensing Inhibitors Based on TraR, LasR, and QscR

2011 ◽  
Vol 16 (9) ◽  
pp. 986-994 ◽  
Author(s):  
Hai-Bo Liu ◽  
Jung Sun Kim ◽  
Sunghoon Park
Keyword(s):  
Quorum Sensing ◽  
Gram Negative Bacteria ◽  
Whole Cell ◽  
Activator Proteins ◽  
Cell Assay ◽  
Quorum Sensing Inhibitors ◽  
Coordinate Gene Expression ◽  
A Cell ◽  
Reporter Strains

Quorum sensing (QS) is a cell density–dependent signaling system that is used by bacteria to coordinate gene expression within their population. In this study, the authors describe the development and characterization of various cell-based bioassay systems for detecting QS inhibitors based on three LuxR family proteins, TraR, LasR, and the recently identified QscR. Three different gram-negative bacteria, Escherichia coli, Agrobacterium tumefaciens, and Pseudomonas aeruginosa, were employed as reporter strains to overproduce one of the aforementioned QS activator proteins and respond to inhibitors. The nine different whole-cell assay systems (three reporter strains × three QS proteins) were evaluated for their applicability and reliability by studying quantitative responses to various furanones, which are potent inhibitors of the LuxR family proteins. These results demonstrate that the cell-based bioassay systems are sensitive and reliable tools for screening of QS activators and inhibitors. This study also suggests that furanones are potentially important QS inhibitors for many LuxR-type activator proteins.

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