Identification of LuxR Family Regulators That Integrate Into Quorum Sensing Circuit in Vibrio parahaemolyticus

Vibrio parahaemolyticus is one of the most important food-borne pathogens that cause economic and public health problems worldwide. Quorum sensing (QS) is a way for the cell-cell communication between bacteria that controls a wide spectrum of processes and phenotypic behaviors. In this study, we performed a systematic research of LuxR family regulators in V. parahaemolyticus and found that they influence the bacterial growth and biofilm formation. We then established a QS reporter plasmid based on bioluminescence luxCDABE operon of Vibrio harveyi and demonstrated that several LuxR family regulators integrated into QS circuit in V. parahaemolyticus. Thereinto, a novel LuxR family regulator, named RobA, was identified as a global regulator by RNA-sequencing analyses, which affected the transcription of 515 genes in V. parahaemolyticus. Subsequent studies confirmed that RobA regulated the expression of the exopolysaccharides (EPS) synthesis cluster and thus controlled the biofilm formation. In addition, bioluminescence reporter assays showed that RobA plays a key role in the QS circuit by regulating the expression of opaR, aphA, cpsQ-mfpABC, cpsS, and scrO. We further demonstrated that the regulation of RobA to EPS and MfpABC depended on OpaR and CpsQ, which combined the QS signal with bis-(3′-5′)-cyclic dimeric GMP to construct a complex regulatory network of biofilm formation. Our data provided new insights into the bacterial QS mechanisms and biofilm formation in V. parahaemolyticus.

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Quorum Sensing – A Stratagem for Conquering Multi-Drug Resistant Pathogens

Current Pharmaceutical Design ◽

10.2174/1381612826666201210105638 ◽

2020 ◽

Vol 26 ◽

Author(s):

Madison Tonkin ◽

Shama Khan ◽

Mohmmad Younus Wani ◽

Aijaz Ahmad

Keyword(s):

Drug Resistance ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Cell Communication ◽

Natural Compounds ◽

Quorum Sensing Inhibitors ◽

Communication Technique ◽

Multicellular Organisms ◽

Chemical Strategies

: Quorum sensing is defined as cell to cell communication between microorganisms, which enables microorganisms to behave as multicellular organisms. Quorum sensing enables many collaborative benefits such as synchronisation of virulence factors and biofilm formation. Both quorum sensing as well as biofilm formation encourage the development of drug resistance in microorganisms. Biofilm formation and quorum sensing are causally linked to each other and play role in the pathogenesis of microorganisms. With the increasing drug resistance against the available antibiotics and antifungal medications, scientists are combining different options to develop new strategies. Such strategies rely on the inhibition of the communication and virulence factors rather than on killing or inhibiting the growth of the microorganisms. This review encompasses the communication technique used by microorganisms, how microorganism resistance is linked to quorum sensing and various chemical strategies to combat quorum sensing and thereby drug resistance. Several compounds have been identified as quorum sensing inhibitors and are known to be effective in reducing resistance as they do not kill the pathogens but rather disrupt their communication. Natural compounds have been identified as anti-quorum sensing agents. However, natural compounds present several related disadvantages. Therefore, the need for the development of synthetic or semi-synthetic compounds has arisen. This review argues that anti-quorum sensing compounds are effective in disrupting quorum sensing and could therefore be effective in reducing microorganism drug resistance.

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Biofilm Formation, Communication and Interactions of Mesophilic Leaching Bacteria during Pyrite Oxidation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.825.107 ◽

2013 ◽

Vol 825 ◽

pp. 107-110

Author(s):

Sören Bellenberg ◽

Robert Barthen ◽

Mario Vera ◽

Nicolas Guiliani ◽

Wolfgang Sand

Keyword(s):

Quorum Sensing ◽

Acidithiobacillus Ferrooxidans ◽

Biofilm Formation ◽

Pyrite Oxidation ◽

Cell Communication ◽

Homoserine Lactone ◽

Mixed Cultures ◽

Acyl Homoserine Lactone ◽

Leaching Bacteria ◽

Leaching Efficiency

A functional luxIR-type Quorum Sensing (QS) system is present in Acidithiobacillus ferrooxidans. However, cell-cell communication among various acidophilic chemolithoautotrophs growing on pyrite has not been studied in detail. These aspects are the scope of this study with emphasis on the effects exerted by the N-acyl-homoserine lactone (AHL) type signaling molecules which are produced by Acidithiobacillus ferrooxidans. Their effects on attachment and leaching efficiency by other leaching bacteria, such as Acidithiobacillus ferrivorans, Acidiferrobacter spp. SPIII/3 and Leptospirillum ferrooxidans in pure and mixed cultures growing on pyrite is shown.

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Peptide Mix from Olivancillaria hiatula Interferes with Cell-to-Cell Communication in Pseudomonas aeruginosa

BioMed Research International ◽

10.1155/2019/5313918 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12

Author(s):

Edward Ntim Gasu ◽

Hubert Senanu Ahor ◽

Lawrence Sheringham Borquaye

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Cell Communication ◽

Microtiter Plate ◽

Antibiofilm Activity ◽

Dependent Manner ◽

Biofilm Inhibition ◽

Swarming Motility

Bacteria in biofilms are encased in an extracellular polymeric matrix that limits exposure of microbial cells to lethal doses of antimicrobial agents, leading to resistance. In Pseudomonas aeruginosa, biofilm formation is regulated by cell-to-cell communication, called quorum sensing. Quorum sensing facilitates a variety of bacterial physiological functions such as swarming motility and protease, pyoverdine, and pyocyanin productions. Peptide mix from the marine mollusc, Olivancillaria hiatula, has been studied for its antibiofilm activity against Pseudomonas aeruginosa. Microscopy and microtiter plate-based assays were used to evaluate biofilm inhibitory activities. Effect of the peptide mix on quorum sensing-mediated processes was also evaluated. Peptide mix proved to be a good antibiofilm agent, requiring less than 39 μg/mL to inhibit 50% biofilm formation. Micrographs obtained confirmed biofilm inhibition at 1/2 MIC whereas 2.5 mg/mL was required to degrade preformed biofilm. There was a marked attenuation in quorum sensing-mediated phenotypes as well. At 1/2 MIC of peptide, the expression of pyocyanin, pyoverdine, and protease was inhibited by 60%, 72%, and 54%, respectively. Additionally, swarming motility was repressed by peptide in a dose-dependent manner. These results suggest that the peptide mix from Olivancillaria hiatula probably inhibits biofilm formation by interfering with cell-to-cell communication in Pseudomonas aeruginosa.

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LitR of Vibrio salmonicida Is a Salinity-Sensitive Quorum-Sensing Regulator of Phenotypes Involved in Host Interactions and Virulence

Infection and Immunity ◽

10.1128/iai.06038-11 ◽

2012 ◽

Vol 80 (5) ◽

pp. 1681-1689 ◽

Cited By ~ 22

Author(s):

Ane Mohn Bjelland ◽

Henning Sørum ◽

Daget Ayana Tegegne ◽

Hanne C. Winther-Larsen ◽

Nils Peder Willassen ◽

...

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Molecular Mechanisms ◽

Cold Water ◽

Bacterial Species ◽

Cell Communication ◽

Cell Aggregation ◽

Fish Host ◽

Content Type ◽

Vibrio Salmonicida

ABSTRACTVibrio(Aliivibrio)salmonicidais the causal agent of cold-water vibriosis, a fatal bacterial septicemia primarily of farmed salmonid fish. The molecular mechanisms of invasion, colonization, and growth ofV. salmonicidain the host are still largely unknown, and few virulence factors have been identified. Quorum sensing (QS) is a cell-to-cell communication system known to regulate virulence and other activities in several bacterial species. The genome ofV. salmonicidaLFI1238 encodes products presumably involved in several QS systems. In this study, the gene encoding LitR, a homolog of the master regulator of QS inV. fischeri, was deleted. Compared to the parental strain, thelitRmutant showed increased motility, adhesion, cell-to-cell aggregation, and biofilm formation. Furthermore, thelitRmutant produced less cryptic bioluminescence, whereas production of acylhomoserine lactones was unaffected. Our results also indicate a salinity-sensitive regulation of LitR. Finally, reduced mortality was observed in Atlantic salmon infected with thelitRmutant, implying that the fish were more susceptible to infection with the wild type than with the mutant strain. We hypothesize that LitR inhibits biofilm formation and favors planktonic growth, with the latter being more adapted for pathogenesis in the fish host.

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Inhibition of Quorum Sensing in Pseudomonas aeruginosa by N-Acyl Cyclopentylamides

Applied and Environmental Microbiology ◽

10.1128/aem.02233-06 ◽

2007 ◽

Vol 73 (10) ◽

pp. 3183-3188 ◽

Cited By ~ 114

Author(s):

Takenori Ishida ◽

Tsukasa Ikeda ◽

Noboru Takiguchi ◽

Akio Kuroda ◽

Hisao Ohtake ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Homoserine Lactone ◽

Ring Structure ◽

Response Regulators ◽

Maximal Inhibition ◽

Sensing Systems ◽

Reporter Assays

ABSTRACT N-Octanoyl cyclopentylamide (C8-CPA) was found to moderately inhibit quorum sensing in Pseudomonas aeruginosa PAO1. To obtain more powerful inhibitors, a series of structural analogs of C8-CPA were synthesized and examined for their ability to inhibit quorum sensing in P. aeruginosa PAO1. The lasB-lacZ and rhlA-lacZ reporter assays revealed that the chain length and the ring structure were critical for C8-CPA analogs to inhibit quorum sensing. N-Decanoyl cyclopentylamide (C10-CPA) was found to be the strongest inhibitor, and its concentrations required for half-maximal inhibition for lasB-lacZ and rhlA-lacZ expression were 80 and 90 μM, respectively. C10-CPA also inhibited production of virulence factors, including elastase, pyocyanin, and rhamnolipid, and biofilm formation without affecting growth of P. aeruginosa PAO1. C10-CPA inhibited induction of both lasI-lacZ by N-(3-oxododecanoyl)-l-homoserine lactone (PAI1) and rhlA-lacZ by N-butanoyl-l-homoserine lactone (PAI2) in the lasI rhlI mutant of P. aeruginosa PAO1, indicating that C10-CPA interferes with the las and rhl quorum-sensing systems via inhibiting interaction between their response regulators (LasR and RhlR) and autoinducers.

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Effects of Natural Products on Bacterial Communication and Network-Quorum Sensing

BioMed Research International ◽

10.1155/2020/8638103 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Min Yang ◽

Fanying Meng ◽

Wen Gu ◽

Fengjiao Li ◽

Yating Tao ◽

...

Keyword(s):

Natural Products ◽

Quorum Sensing ◽

Virulence Factor ◽

Biofilm Formation ◽

Bacterial Flora ◽

External Environment ◽

Cell Communication ◽

Beneficial Bacteria ◽

Bacterial Communication ◽

Virulence Factor Production

Quorum sensing (QS) has emerged as a research hotspot in microbiology and medicine. QS is a regulatory cell communication system used by bacterial flora to signal to the external environment. QS influences bacterial growth, proliferation, biofilm formation, virulence factor production, antibiotic synthesis, and environmental adaptation. Through the QS system, natural products can regulate the growth of harmful bacteria and enhance the growth of beneficial bacteria, thereby improving human health. Herein, we review advances in the discovery of natural products that regulate bacterial QS systems.

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A pivotal role for the response regulator DegU in controlling multicellular behaviour

Microbiology ◽

10.1099/mic.0.023903-0 ◽

2009 ◽

Vol 155 (1) ◽

pp. 1-8 ◽

Cited By ~ 73

Author(s):

Ewan J. Murray ◽

Taryn B. Kiley ◽

Nicola R. Stanley-Wall

Keyword(s):

Cell Fate ◽

Biofilm Formation ◽

Molecular Mechanisms ◽

Response Regulator ◽

Regulatory System ◽

Environmental Cues ◽

Swarming Motility ◽

Food Borne ◽

Novel Targets ◽

Complex Regulatory Network

Bacteria control multicellular behavioural responses, including biofilm formation and swarming motility, by integrating environmental cues through a complex regulatory network. Heterogeneous gene expression within an otherwise isogenic cell population that allows for differentiation of cell fate is an intriguing phenomenon that adds to the complexity of multicellular behaviour. This review focuses on recent data about how DegU, a pleiotropic response regulator, co-ordinates multicellular behaviour in Bacillus subtilis. We review studies that challenge the conventional understanding of the molecular mechanisms underpinning the DegU regulatory system and others that describe novel targets of DegU during activation of biofilm formation by B. subtilis. We also discuss a novel role for DegU in regulating multicellular processes in the food-borne pathogen Listeria monocytogenes.

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Regulatory small RNA, Qrr2, is expressed independently of sigma factor-54 and functions autonomously in Vibrio parahaemolyticus to control quorum sensing

10.1101/2021.07.01.450815 ◽

2021 ◽

Author(s):

Jessica Tague ◽

Jisoo Hong ◽

Sai S Kalburge ◽

Ethna Fidelma Boyd

Keyword(s):

Quorum Sensing ◽

Sigma Factor ◽

Vibrio Parahaemolyticus ◽

Regulatory Region ◽

Bacterial Cells ◽

Biofilm Production ◽

Luxr Homolog ◽

Reporter Assays ◽

Sigma 70 ◽

Low Cell Density

Bacterial cells alter gene expression in response to changes in population density in a process called quorum sensing (QS). In Vibrio harveyi, LuxO, a low cell density activator of sigma factor-54 (RpoN), is required for transcription of five non-coding regulatory sRNAs, Qrr1-Qrr5, which each repress translation of the master QS regulator LuxR. Vibrio parahaemolyticus, the leading cause of bacterial seafood-borne gastroenteritis, also contains five Qrr sRNAs that control OpaR (the LuxR homolog), required for capsule polysaccharide (CPS) and biofilm production, motility, and metabolism. We show that in a ΔluxO deletion mutant, opaR was de-repressed and CPS and biofilm were produced. However, in a ΔrpoN mutant, opaR was repressed, no CPS was produced, and less biofilm production was observed compared to wild type. To determine why opaR was repressed, expression analysis in ΔluxO showed all five qrr genes were repressed, while in ΔrpoN the qrr2 gene was significantly de-repressed. Reporter assays and mutant analysis showed Qrr2 sRNA can act autonomously to control OpaR. Bioinformatics analysis identified a sigma-70 (RpoD) -35 -10 promoter overlapping the canonical sigma-54 (RpoN) promoter in the qrr2 regulatory region. Mutagenesis of the sigma-70 -10 promoter site in the ΔrpoN mutant background, resulted in repression of qrr2. Analysis of qrr quadruple deletion mutants, in which only a single qrr gene is present, showed that only Qrr2 sRNA can act autonomously to regulate opaR. Mutant and expression data also demonstrated that RpoN and the global regulator Fis act additively to repress qrr2. Our data has uncovered a new mechanism of qrr expression and shows that Qrr2 sRNA is sufficient for OpaR regulation.

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Vibrio alginolyticus influences quorum sensing-controlled phenotypes of acute hepatopancreatic necrosis disease-causing Vibrio parahaemolyticus

PeerJ ◽

10.7717/peerj.11567 ◽

2021 ◽

Vol 9 ◽

pp. e11567

Author(s):

Panida Paopradit ◽

Natta Tansila ◽

Komwit Surachat ◽

Pimonsri Mittraparp-arthorn

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Vibrio Parahaemolyticus ◽

Extracellular Polymeric Substances ◽

Capsular Polysaccharide ◽

Regulatory Gene ◽

Challenge Test ◽

Great Ability ◽

Acute Hepatopancreatic Necrosis Disease ◽

Reporter Bacteria

Background Acute hepatopancreatic necrosis syndrome (AHPND) caused by Vibrio parahaemolyticus strain (VPAHPND) impacts the shrimp industry worldwide. With the increasing problem of antibiotic abuse, studies on quorum sensing (QS) system and anti-QS compounds bring potential breakthroughs for disease prevention and treatment. Methods In this study, the cell-free culture supernatant (CFCS) and its extract of V. alginolyticus BC25 were investigated for anti-QS activity against a reporter bacteria, Chromobacterium violaceum DMST46846. The effects of CFCS and/ or extract on motility, biofilm formation and extracellular polymeric substances (EPSs) of VPAHPND PSU5591 were evaluated. Moreover, the effects of V. alginolyticus BC25 on virulence of VPAHPND PSU5591 were investigated by shrimp challenge test. The potentially active anti-QS compounds presented in the extract and effect on gene expression of VPAHPND PSU5591 were identified. Results The CFCS of V. alginolyticus BC25 and its extract showed a significant anti-QS activity against the reporter bacteria as well as swimming and swarming motilities, biofilms, and EPSs production by VPAHPND PSU5591. Transcriptome analysis revealed that V. alginolyticus BC25 extract significantly reduced the flagella genes involved in biofilm formation and iron-controlled virulence regulatory gene of VPAHPND PSU5591. Whereas, the LuxR family transcriptional regulator gene, c-factor, a cell-cell signaling gene, and capsular polysaccharide were up-regulated. The potentially active anti-QS compounds identified in extract were Cyclo-(L-Leu-L-Pro), and Cyclo-(L-Phe-L-Pro). Furthermore, V. alginolyticus BC25 enhanced disease resistance against VPAHPND PSU5591 in tested shrimp larvae. Conclusion These findings suggest that V. alginolyticus BC25 could provide natural anti-QS and anti-biofilms compounds and has great ability to be used as biocontrol agent against VPAHPND infection in shrimp aquaculture.

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