Autoinducer‐2‐mediated quorum‐sensing system resists T4 phage infection in Escherichia coli

2021 ◽  
Author(s):  
Yafang Ding ◽  
Dongfang Zhang ◽  
Xiaoman Zhao ◽  
Wenzhang Tan ◽  
Xiaodan Zheng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Phage Infection ◽  
Sensing System ◽  
Autoinducer 2 ◽  
Quorum Sensing System ◽  
T4 Phage

scholarly journals Expression of a luxS Gene Is Not Required for Borrelia burgdorferi Infection of Mice via Needle Inoculation

2003 ◽  
Vol 71 (5) ◽  
pp. 2892-2896 ◽  
Author(s):  
Anette Hübner ◽  
Andrew T. Revel ◽  
Dena M. Nolen ◽  
Kayla E. Hagman ◽  
Michael V. Norgard
Keyword(s):  
Quorum Sensing ◽  
Borrelia Burgdorferi ◽  
Mammalian Host ◽  
Wild Type ◽  
Sensing System ◽  
Autoinducer 2 ◽  
Sensing Systems ◽  
Quorum Sensing System ◽  
Culture Supernatants

ABSTRACT The luxS gene product is an integral component of LuxS/autoinducer-2 (AI-2) quorum-sensing systems in bacteria. A putative luxS gene was expressed at comparable levels by Borrelia burgdorferi strain 297 cultivated either in vitro or in dialysis membrane chambers implanted in rat peritoneal cavities. Although the borrelial luxS gene functionally complemented a LuxS deficiency in Escherichia coli DH5α, AI-2-like activity could not be detected within B. burgdorferi culture supernatants or concentrated cell lysates. Finally, a luxS-deficient mutant of B. burgdorferi was infectious at wild-type levels when it was intradermally needle inoculated into mice, indicating that expression of luxS probably is not required for infectivity but, at the very least, is not essential for mammalian host adaptation. Our findings also challenge the notion that a LuxS/AI-2 quorum-sensing system is operative in B. burgdorferi.

scholarly journals Role of the luxS Quorum-Sensing System in Biofilm Formation and Virulence of Staphylococcus epidermidis

2006 ◽  
Vol 74 (1) ◽  
pp. 488-496 ◽  
Author(s):  
Lin Xu ◽  
Hualin Li ◽  
Cuong Vuong ◽  
Viveka Vadyvaloo ◽  
Jianping Wang ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Mutant Strain ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Pathogens ◽  
Sensing System ◽  
Autoinducer 2 ◽  
Enhanced Production ◽  
Quorum Sensing System ◽  
Biofilm Development

ABSTRACT Nosocomial infections caused by Staphylococcus epidermidis are characterized by biofilm formation on implanted medical devices. Quorum-sensing regulation plays a major role in the biofilm development of many bacterial pathogens. Here, we describe luxS, a quorum-sensing system in staphylococci that has a significant impact on biofilm development and virulence. We constructed an isogenic ΔluxS mutant strain of a biofilm-forming clinical isolate of S. epidermidis and demonstrated that luxS signaling is functional in S. epidermidis. The mutant strain showed increased biofilm formation in vitro and enhanced virulence in a rat model of biofilm-associated infection. Genetic complementation and addition of autoinducer 2-containing culture filtrate restored the wild-type phenotype, demonstrating that luxS repressed biofilm formation through a cell-cell signaling mechanism based on autoinducer 2 secretion. Enhanced production of the biofilm exopolysaccharide polysaccharide intercellular adhesin in the mutant strain is presumably the major cause of the observed phenotype. The agr quorum-sensing system has previously been shown to impact biofilm development and biofilm-associated infection in a way similar to that of luxS, although by regulation of different factors. Our study indicates a general scheme of quorum-sensing regulation of biofilm development in staphylococci, which contrasts with that observed in many other bacterial pathogens.

Genetic and functional diversity of PsyI/PsyR quorum-sensing system in the Pseudomonas syringae complex

2020 ◽  
Author(s):  
Tomohiro Morohoshi ◽  
Akinori Oshima ◽  
Xiaonan Xie ◽  
Nobutaka Someya
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Pseudomonas Syringae ◽  
Dna Sequences ◽  
Homoserine Lactone ◽  
Sensing System ◽  
Sensing Systems ◽  
Quorum Sensing System ◽  
High Level ◽  
Functionally Diverse

Abstract Strains belonging to the Pseudomonas syringae complex often possess quorum-sensing systems that comprise N-acyl-l-homoserine lactone (AHL) synthase (PsyI) and AHL receptors (PsyR). Here, we investigated the diversity of PsyI/PsyR quorum-sensing systems in 630 strains of the P. syringae complex. AHL production was observed in most strains of P. amygdali and P. meliae, and a few strains of P. coronafaciens and P. syringae. The DNA sequences of psyIR and their upstream and downstream regions were categorized into eight types. P. amygdali pv. myricae, P. savastanoi, and P. syringae pv. solidagae, maculicola, broussonetiae, and tomato encoded psyI, but did not produce detectable amounts of AHL. In P. savastanoi, an amino acid substitution (R27S) in PsyI caused defective AHL production. The psyI gene of P. syringae pv. tomato was converted to pseudogenes by frameshift mutations. Escherichia coli harboring psyI genes from P. amygdali pv. myricae, P. syringae pv. solidagae and broussonetiae showed high level of AHL production. Forced expression of functional psyR restored AHL production in P. amygdali pv. myricae and P. syringae pv. solidagae. In conclusion, our study indicates that the PsyI/PsyR quorum-sensing systems in P. syringae strains are genetically and functionally diverse, with diversity being linked to phylogenetic and pathovar classifications.

scholarly journals The Burkholderia mallei BmaR3-BmaI3 Quorum-Sensing System Produces and Responds to N-3-Hydroxy-Octanoyl Homoserine Lactone

2008 ◽  
Vol 190 (14) ◽  
pp. 5137-5141 ◽  
Author(s):  
Breck A. Duerkop ◽  
Jake P. Herman ◽  
Ricky L. Ulrich ◽  
Mair E. A. Churchill ◽  
E. Peter Greenberg
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Mallei ◽  
E Coli ◽  
Additional Signal ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Signal Receptors

ABSTRACT Burkholderia mallei has two acyl-homoserine lactone (acyl-HSL) signal generator-receptor pairs and two additional signal receptors, all of which contribute to virulence. We show that B. mallei produces N-3-hydroxy-octanoyl HSL (3OHC8-HSL) but a bmaI3 mutant does not. Recombinant Escherichia coli expressing BmaI3 produces hydroxylated acyl-HSLs, with 3OHC8-HSL being the most abundant compound. In recombinant E. coli, BmaR3 responds to 3OHC8-HSL but not to other acyl-HSLs. These data indicate that the signal for BmaR3-BmaI3 quorum sensing is 3OHC8-HSL.

scholarly journals Quantifying the optimal strategy of population control of quorum sensing network in Escherichia coli

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiang Li ◽  
Jun Jin ◽  
Xiaocui Zhang ◽  
Fei Xu ◽  
Jinjin Zhong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Population Density ◽  
Oscillatory Behavior ◽  
High Dose ◽  
Stochastic Dynamic ◽  
Iptg Induction ◽  
Sensing System ◽  
Quorum Sensing System ◽  
By Products

AbstractBiological functions of bacteria can be regulated by monitoring their own population density induced by the quorum sensing system. However, quantitative insight into the system’s dynamics and regulatory mechanism remain challenging. Here, we construct a comprehensive mathematical model of the synthetic quorum sensing circuit that controls population density in Escherichia coli. Simulations agree well with experimental results obtained under different ribosome-binding site (RBS) efficiencies. We present a quantitative description of the component dynamics and show how the components respond to isopropyl-β-D-1-thiogalactopyranoside (IPTG) induction. The optimal IPTG-induction range for efficiently controlling population density is quantified. The controllable area of population density by acyl-homoserine lactone (AHL) permeability is quantified as well, indicating that high AHL permeability should be treated with a high dose of IPTG, while low AHL permeability should be induced with low dose for efficiently controlling. Unexpectedly, an oscillatory behavior of the growth curve is observed with proper RBS-binding strengths and the oscillation is greatly restricted by the bacterial death induced by toxic metabolic by-products. Moreover, we identify that the mechanism underlying the emergence of oscillation is determined by the negative feedback loop structure within the signaling. Bifurcation analysis and landscape theory are further employed to study the stochastic dynamic and global stability of the system, revealing two faces of toxic metabolic by-products in controlling oscillatory behavior. Overall, our study presents a quantitative basis for understanding and new insights into the control mechanism of quorum sensing system, providing possible clues to guide the development of more rational control strategy.

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