Signal-mediated cross-talk regulates stress adaptation in Vibrio species

Quorum sensing systems serve as a means of ‘census taking’ of conspecific and non-conspecific bacteria in the near vicinity. The acylated homoserine lactone (AHL) quorum sensing system has been proposed to be primarily an intra-specific communication system, while the AI-2 autoinducer signalling system is proposed to be an interspecific communication system. Here it is shown that AI-2-like signalling in two marine Vibrio species, Vibrio vulnificus and ‘Vibrio angustum’ S14, induces the core response phenotypes of starvation adaptation and stress resistance, and that a signal antagonist can competitively inhibit these phenotypes. Furthermore, the signals produced by a range of Vibrio species have the ability to induce these phenotypes in V. vulnificus and ‘V. angustum’ S14, indicating that, at least in Vibrio species, AI-2-like signalling systems function as interspecies communication systems capable of ‘cross-talk’ and of regulating environmentally relevant phenotypes.

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N-Octanoylhomoserine lactone signalling mediated by the BpsI–BpsR quorum sensing system plays a major role in biofilm formation of Burkholderia pseudomallei

Microbiology ◽

10.1099/mic.0.046540-0 ◽

2011 ◽

Vol 157 (4) ◽

pp. 1176-1186 ◽

Cited By ~ 37

Author(s):

Akshamal Mihiranga Gamage ◽

Guanghou Shui ◽

Markus R. Wenk ◽

Kim Lee Chua

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Burkholderia Pseudomallei ◽

Homoserine Lactone ◽

Tandem Ms ◽

Wild Type ◽

Acylhomoserine Lactone ◽

Sensing System ◽

Sensing Systems ◽

Quorum Sensing System

The genome of Burkholderia pseudomallei encodes three acylhomoserine lactone (AHL) quorum sensing systems, each comprising an AHL synthase and a signal receptor/regulator. The BpsI–BpsR system produces N-octanoylhomoserine lactone (C8HL) and is positively auto-regulated by its AHL product. The products of the remaining two systems have not been identified. In this study, tandem MS was used to identify and quantify the AHL species produced by three clinical B. pseudomallei isolates – KHW, K96243 and H11 – three isogenic KHW mutants that each contain a null mutation in an AHL synthase gene, and recombinant Escherichia coli heterologously expressing each of the three B. pseudomallei AHL synthase genes. BpsI synthesized predominantly C8HL, which accounted for more than 95 % of the extracellular AHLs produced in stationary-phase KHW cultures. The major products of BpsI2 and BpsI3 were N-(3-hydroxy-octanoyl)homoserine lactone (OHC8HL) and N-(3-hydroxy-decanoyl)homoserine lactone, respectively, and their corresponding transcriptional regulators, BpsR2 and BpsR3, were capable of driving reporter gene expression in the presence of these cognate lactones. Formation of biofilm by B. pseudomallei KHW was severely impaired in mutants lacking either BpsI or BpsR but could be restored to near wild-type levels by exogenous C8HL. BpsI2 was not required, and BpsI3 was partially required for biofilm formation. Unlike the bpsI mutant, biofilm formation in the bpsI3 mutant could not be restored to wild-type levels in the presence of OHC8HL, the product of BpsI3. C8HL and OHC8HL had opposite effects on biofilm formation; exogenous C8HL enhanced biofilm formation in both the bpsI3 mutant and wild-type KHW while exogenous OHC8HL suppressed the formation of biofilm in the same strains. We propose that exogenous OHC8HL antagonizes biofilm formation in B. pseudomallei, possibly by competing with endogenous C8HL for binding to BpsR.

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The Pseudomonas Quinolone Signal Regulates rhl Quorum Sensing in Pseudomonas aeruginosa

Journal of Bacteriology ◽

10.1128/jb.182.10.2702-2708.2000 ◽

2000 ◽

Vol 182 (10) ◽

pp. 2702-2708 ◽

Cited By ~ 259

Author(s):

Susan L. McKnight ◽

Barbara H. Iglewski ◽

Everett C. Pesci

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Opportunistic Pathogen ◽

Homoserine Lactone ◽

Sensing System ◽

Sensing Systems ◽

Pseudomonas Quinolone Signal ◽

Quorum Sensing System ◽

Encoding Gene

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa uses intercellular signals to control the density-dependent expression of many virulence factors. The las and rhlquorum-sensing systems function, respectively, through the autoinducersN-(3-oxododecanoyl)-l-homoserine lactone andN-butyryl-l-homoserine lactone (C4-HSL), which are known to positively regulate the transcription of the elastase-encoding gene, lasB. Recently, we reported that a second type of intercellular signal is involved in lasB induction. This signal was identified as 2-heptyl-3-hydroxy-4-quinolone and designated thePseudomonas quinolone signal (PQS). PQS was determined to be part of the quorum-sensing hierarchy since its production and bioactivity depended on the las and rhlquorum-sensing systems, respectively. In order to define the role of PQS in the P. aeruginosa quorum-sensing cascade,lacZ gene fusions were used to determine the effect of PQS on the transcription of the quorum-sensing system geneslasR, lasI, rhlR, andrhlI. We found that in P. aeruginosa, PQS caused a major induction of rhlI′-lacZ and had lesser effects on the transcription of lasR′-lacZ andrhlR′-lacZ. We also observed that the transcription of bothrhlI′-lacZ and lasB′-lacZ was cooperatively effected by C4-HSL and PQS. Additionally, we present data indicating that PQS was not produced maximally until cultures reached the late stationary phase of growth. Taken together, our results imply that PQS acts as a link between the las and rhlquorum-sensing systems and that this signal is not involved in sensing cell density.

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Expression of the bviIR and cepIR Quorum-Sensing Systems of Burkholderia vietnamiensis

Journal of Bacteriology ◽

10.1128/jb.01544-06 ◽

2007 ◽

Vol 189 (8) ◽

pp. 3006-3016 ◽

Cited By ~ 20

Author(s):

Rebecca J. Malott ◽

Pamela A. Sokol

Keyword(s):

Quorum Sensing ◽

Burkholderia Cepacia ◽

Regulatory Element ◽

Transcriptional Regulator ◽

Homoserine Lactone ◽

Burkholderia Vietnamiensis ◽

Sensing System ◽

Sensing Systems ◽

Quorum Sensing System ◽

Regulatory Organization

ABSTRACT Burkholderia vietnamiensis has both the cepIR quorum-sensing system that is widely distributed among the Burkholderia cepacia complex (BCC) and the bviIR system. Comparison of the expression of cepI, cepR, bviI, and bviR-luxCDABE fusions in B. vietnamiensis G4 and the G4 cepR and bviR mutants determined that the expression of bviI requires both a functional cognate regulator, BviR, and functional CepR. The cepIR system, however, is not regulated by BviR. Unlike the cepIR genes in other BCC species, the cepIR genes are not autoregulated in G4. N-Acyl-homoserine lactone (AHL) production profiles in G4 cepI, cepR, bviI, and bviR mutants confirmed the regulatory organization of the G4 quorum-sensing systems. The regulatory network in strain PC259 is similar to that in G4, except that CepR positively regulates cepI and negatively regulates cepR. AHL production and the bviI expression levels in seven B. vietnamiensis isolates were compared. All strains produced N-octanoyl-homoserine lactone and N-hexanoyl-homoserine lactone; however, only one of four clinical strains but all three environmental strains produced the BviI synthase product, N-decanoyl-homoserine lactone (DHL). The three strains that did not produce DHL expressed bviR but not bviI. Heterologous expression of bviR restored DHL production in these strains. The bviIR loci of the non-DHL-producing strains were sequenced to confirm that bviR encodes a functional transcriptional regulator. Lack of expression of G4 bviI in these three strains indicated that an additional regulatory element may be involved in the regulation of bviIR expression in certain strains of B. vietnamiensis.

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

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa254 ◽

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.

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Inhibition of exoprotease production in Aeromonas hydrophila by rhizome extract of temu lawak (Curcuma xanthorrhiza (Roxb.)

Biofarmasi Journal of Natural Product Biochemistry ◽

10.13057/biofar/f040202 ◽

2006 ◽

Vol 4 (2) ◽

pp. 45-54

Author(s):

UMI LESTARI ◽

ARTINI PANGASTUTI ◽

ARI SUSILOWATI

Keyword(s):

Quorum Sensing ◽

Ethyl Acetate ◽

Aeromonas Hydrophila ◽

Ethanol Extract ◽

Homoserine Lactone ◽

Sensing System ◽

Development Of Resistance ◽

Quorum Sensing System ◽

Assay Result ◽

Curcuma Xanthorrhiza

Conventional treatment of infectious diseases is based on compounds that kill or inhibit the growth of bacteria. A major concern with this approach is the frequent development of resistance to antimicrobial compounds. The discovery of communication (quorum sensing system) regulating bacterial virulence opens up ways to control certain bacterial infectious without interfering the growth. The fish pathogen Aeromonas hydrophila produces quorum sensing signal, NButanoyl-L-Homoserine Lactone (C4-HSL). C4-HSL regulates exoprotease synthesis, a virulence factor of A. hydrophila. Expression of exoprotease can be blocked by using quorum sensing inhibitor. The purpose of this study was to investigate the inhibiting effect of Curcuma xanthorrhiza (Roxb.) extract to exoprotease production of A. hydrophila. Extraction was conducted by using n-hexane, ethyl acetate and ethanol. The qualitative exoprotease assay result showed that n-hexane extract of C. xanthorrhiza had not effect on growth and exoprotease production of A. hydrophila. Meanwhile, 4% of ethyl acetate and ethanol extract of C. xanthorrhiza can inhibit exoprotease production without affecting A. hydrophilla growth. The quantitative exoprotease assay result showed that 4% of ethyl acetate and ethanol extract can inhibit the exoprotease production by 93,9% and 95,6%. The growth of A. hydrophila was not affected by this extract.

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Characterization of a luxI/luxR-type quorum sensing system and N-acyl homoserine lactone-dependent regulation of exo-enzyme and antibacterial component production in Serratia plymuthica RVH1

Research in Microbiology ◽

10.1016/j.resmic.2006.11.012 ◽

2007 ◽

Cited By ~ 1

Author(s):

Rob Van Houdt ◽

Pieter Moons ◽

Abram Aertsen ◽

An Jansen ◽

Kristof Vanoirbeek ◽

...

Keyword(s):

Quorum Sensing ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone ◽

Serratia Plymuthica ◽

Sensing System ◽

Quorum Sensing System ◽

Component Production

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A Mobile Quorum-Sensing System in Serratia marcescens

Journal of Bacteriology ◽

10.1128/jb.188.4.1518-1525.2006 ◽

2006 ◽

Vol 188 (4) ◽

pp. 1518-1525 ◽

Cited By ~ 37

Author(s):

Jun-Rong Wei ◽

Yu-Huan Tsai ◽

Yu-Tze Horng ◽

Po-Chi Soo ◽

Shang-Chen Hsieh ◽

...

Keyword(s):

Quorum Sensing ◽

Population Density ◽

Serratia Marcescens ◽

Biological Functions ◽

New Host ◽

Transposition Frequency ◽

Evolutionary Mechanism ◽

Sensing System ◽

Sensing Systems ◽

Quorum Sensing System

ABSTRACT Quorum-sensing systems that have been widely identified in bacteria play important roles in the regulation of bacterial multicellular behavior by which bacteria sense population density to control various biological functions, including virulence. One characteristic of the luxIR quorum-sensing genes is their diverse and discontinuous distribution among proteobacteria. Here we report that the spnIR quorum-sensing system identified in the enterobacterium Serratia marcescens strain SS-1 is carried in a transposon, TnTIR, which has common characteristics of Tn3 family transposons and is mobile between chromosomes and plasmids of different enterobacterial hosts. SpnIR functions in the new host and was shown to negatively regulate the TnTIR transposition frequency. This finding may help reveal the horizontal transfer and evolutionary mechanism of quorum-sensing genes and alter the way that we perceive regulation of bacterial multicellular behavior.

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PqsE Functions Independently of PqsR-Pseudomonas Quinolone Signal and Enhances the rhl Quorum-Sensing System

Journal of Bacteriology ◽

10.1128/jb.00753-08 ◽

2008 ◽

Vol 190 (21) ◽

pp. 7043-7051 ◽

Cited By ~ 105

Author(s):

John M. Farrow ◽

Zoe M. Sund ◽

Matthew L. Ellison ◽

Dana S. Wade ◽

James P. Coleman ◽

...

Keyword(s):

Quorum Sensing ◽

Virulence Factors ◽

Opportunistic Pathogen ◽

Homoserine Lactone ◽

Chronic Infections ◽

Signaling Systems ◽

Sensing System ◽

Pseudomonas Quinolone Signal ◽

Quorum Sensing System ◽

Hostile Environments

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that causes both acute and chronic infections in immunocompromised individuals. This gram-negative bacterium produces a battery of virulence factors that allow it to infect and survive in many different hostile environments. The control of many of these virulence factors falls under the influence of one of three P. aeruginosa cell-to-cell signaling systems. The focus of this study, the quinolone signaling system, functions through the Pseudomonas quinolone signal (PQS), previously identified as 2-heptyl-3-hydroxy-4-quinolone. This signal binds to and activates the LysR-type transcriptional regulator PqsR (also known as MvfR), which in turn induces the expression of the pqsABCDE operon. The first four genes of this operon are required for PQS synthesis, but the fifth gene, pqsE, is not. The function of the pqsE gene is not known, but it is required for the production of multiple PQS-controlled virulence factors and for virulence in multiple models of infection. In this report, we show that PqsE can activate PQS-controlled genes in the absence of PqsR and PQS. Our data also suggest that the regulatory activity of PqsE requires RhlR and indicate that a pqsE mutant can be complemented for pyocyanin production by a large excess of exogenous N-butyryl homoserine lactone (C4-HSL). Finally, we show that PqsE enhances the ability of Escherichia coli expressing RhlR to respond to C4-HSL. Overall, our data lead us to conclude that PqsE functions as a regulator that is independent of PqsR and PQS but dependent on the rhl quorum-sensing system.

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

Infection and Immunity ◽

10.1128/iai.71.5.2892-2896.2003 ◽

2003 ◽

Vol 71 (5) ◽

pp. 2892-2896 ◽

Cited By ~ 44

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.

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