Temporal Quorum-Sensing Induction Regulates Vibrio cholerae Biofilm Architecture

ABSTRACT Vibrio cholerae, the pathogen that causes cholera, also survives in aqueous reservoirs, probably in the form of biofilms. Quorum sensing negatively regulates V. cholerae biofilm formation through HapR, whose expression is induced at a high cell density. In this study, we show that the concentration of the quorum-sensing signal molecule CAI-1 is higher in biofilms than in planktonic cultures. By measuring hapR expression and activity, we found that the induction of quorum sensing in biofilm-associated cells occurs earlier. We further demonstrate that the timing of hapR expression is crucial for biofilm thickness, biofilm detachment rates, and intestinal colonization efficiency. These results suggest that V. cholerae is able to regulate its biofilm architecture by temporal induction of quorum-sensing systems.

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Quorum Sensing Controls Biofilm Formation in Vibrio cholerae through Modulation of Cyclic Di-GMP Levels and Repression of vpsT

Journal of Bacteriology ◽

10.1128/jb.01756-07 ◽

2008 ◽

Vol 190 (7) ◽

pp. 2527-2536 ◽

Cited By ~ 266

Author(s):

Christopher M. Waters ◽

Wenyun Lu ◽

Joshua D. Rabinowitz ◽

Bonnie L. Bassler

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

Biofilm Formation ◽

High Cell Density ◽

High Cell ◽

Chemical Signaling ◽

Signaling Systems ◽

Genes Encoding ◽

Low Cell Density

ABSTRACT Two chemical signaling systems, quorum sensing (QS) and 3′,5′-cyclic diguanylic acid (c-di-GMP), reciprocally control biofilm formation in Vibrio cholerae. QS is the process by which bacteria communicate via the secretion and detection of autoinducers, and in V. cholerae, QS represses biofilm formation. c-di-GMP is an intracellular second messenger that contains information regarding local environmental conditions, and in V. cholerae, c-di-GMP activates biofilm formation. Here we show that HapR, a major regulator of QS, represses biofilm formation in V. cholerae through two distinct mechanisms. HapR controls the transcription of 14 genes encoding a group of proteins that synthesize and degrade c-di-GMP. The net effect of this transcriptional program is a reduction in cellular c-di-GMP levels at high cell density and, consequently, a decrease in biofilm formation. Increasing the c-di-GMP concentration at high cell density to the level present in the low-cell-density QS state restores biofilm formation, showing that c-di-GMP is epistatic to QS in the control of biofilm formation in V. cholerae. In addition, HapR binds to and directly represses the expression of the biofilm transcriptional activator, vpsT. Together, our results suggest that V. cholerae integrates information about the vicinal bacterial community contained in extracellular QS autoinducers with the intracellular environmental information encoded in c-di-GMP to control biofilm formation.

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Faculty Opinions recommendation of The intragenus and interspecies quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.736889131.793569873 ◽

2020 ◽

Author(s):

Jan Roelof van der Meer ◽

Nicolas Carraro

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Biofilm Formation

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Parallel Quorum Sensing Systems Converge to Regulate Virulence in Vibrio cholerae

Cell ◽

10.1016/s0092-8674(02)00829-2 ◽

2002 ◽

Vol 110 (3) ◽

pp. 303-314 ◽

Cited By ~ 453

Author(s):

Melissa B. Miller ◽

Karen Skorupski ◽

Derrick H. Lenz ◽

Ronald K. Taylor ◽

Bonnie L. Bassler

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Sensing Systems

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Indole Acts as an Extracellular Cue Regulating Gene Expression in Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.01240-08 ◽

2009 ◽

Vol 191 (11) ◽

pp. 3504-3516 ◽

Cited By ~ 109

Author(s):

Ryan S. Mueller ◽

Sinem Beyhan ◽

Simran G. Saini ◽

Fitnat H. Yildiz ◽

Douglas H. Bartlett

Keyword(s):

Gene Expression ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Signal Molecule ◽

Control Of Gene Expression ◽

Protozoan Grazing ◽

Extracellular Signal ◽

Grazing Resistance ◽

Indole Signaling

ABSTRACT Indole has been proposed to act as an extracellular signal molecule influencing biofilm formation in a range of bacteria. For this study, the role of indole in Vibrio cholerae biofilm formation was examined. It was shown that indole activates genes involved in vibrio polysaccharide (VPS) production, which is essential for V. cholerae biofilm formation. In addition to activating these genes, it was determined using microarrays that indole influences the expression of many other genes, including those involved in motility, protozoan grazing resistance, iron utilization, and ion transport. A transposon mutagenesis screen revealed additional components of the indole-VPS regulatory circuitry. The indole signaling cascade includes the DksA protein along with known regulators of VPS production, VpsR and CdgA. A working model is presented in which global control of gene expression by indole is coordinated through σ54 and associated transcriptional regulators.

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Anti-quorum Sensing Systems and Biofilm Formation

Nanotechnology in the Life Sciences - Nanostructures for Antimicrobial and Antibiofilm Applications ◽

10.1007/978-3-030-40337-9_12 ◽

2020 ◽

pp. 293-303

Author(s):

Sarangam Majumdar

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Sensing Systems

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Inhibition of Quorum Sensing in Serratia marcescens AS-1 by Synthetic Analogs of N-Acylhomoserine Lactone

Applied and Environmental Microbiology ◽

10.1128/aem.00593-07 ◽

2007 ◽

Vol 73 (20) ◽

pp. 6339-6344 ◽

Cited By ~ 80

Author(s):

Tomohiro Morohoshi ◽

Toshitaka Shiono ◽

Kiyomi Takidouchi ◽

Masashi Kato ◽

Norihiro Kato ◽

...

Keyword(s):

Quorum Sensing ◽

Serratia Marcescens ◽

Biofilm Formation ◽

Acyl Chain ◽

Regulatory System ◽

Homoserine Lactone ◽

Signal Molecule ◽

Swarming Motility ◽

Gram Negative ◽

Acylhomoserine Lactone

ABSTRACT Quorum sensing is a regulatory system for controlling gene expression in response to increasing cell density. N-Acylhomoserine lactone (AHL) is produced by gram-negative bacteria, which use it as a quorum-sensing signal molecule. Serratia marcescens is a gram-negative opportunistic pathogen which is responsible for an increasing number of serious nosocomial infections. S. marcescens AS-1 produces N-hexanoyl homoserine lactone (C6-HSL) and N-(3-oxohexanoyl) homoserine lactone and regulates prodigiosin production, swarming motility, and biofilm formation by AHL-mediated quorum sensing. We synthesized a series of N-acyl cyclopentylamides with acyl chain lengths ranging from 4 to 12 and estimated their inhibitory effects on prodigiosin production in AS-1. One of these molecules, N-nonanoyl-cyclopentylamide (C9-CPA), had a strong inhibitory effect on prodigiosin production. C9-CPA also inhibited the swarming motility and biofilm formation of AS-1. A competition assay revealed that C9-CPA was able to inhibit quorum sensing at four times the concentration of exogenous C6-HSL and was more effective than the previously reported halogenated furanone. Our results demonstrated that C9-CPA was an effective quorum-sensing inhibitor for S. marcescens AS-1.

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The intra-genus and inter-species quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal

10.1101/713685 ◽

2019 ◽

Author(s):

Andrew A. Bridges ◽

Bonnie L. Bassler

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

Biofilm Formation ◽

Specific Information ◽

High Cell ◽

Coincidence Detector ◽

Sensing System ◽

Quorum Sensing System ◽

Cell Densities

AbstractVibrio cholerae possesses multiple quorum-sensing systems that control virulence and biofilm formation among other traits. At low cell densities, when quorum-sensing autoinducers are absent, V. cholerae forms biofilms. At high cell densities, when autoinducers have accumulated, biofilm formation is repressed and dispersal occurs. Here, we focus on the roles of two well-characterized quorum-sensing autoinducers that function in parallel. One autoinducer, called CAI-1, is used to measure vibrio abundance, and the other autoinducer, called AI-2, is a broadly-made universal autoinducer that is presumed to enable V. cholerae to assess the total bacterial cell density of the vicinal community. The two V. cholerae autoinducers funnel information into a shared signal relay pathway. This feature of the quorum-sensing system architecture has made it difficult to understand how specific information can be extracted from each autoinducer, how the autoinducers might drive distinct output behaviors, and in turn, how the bacteria use quorum sensing to distinguish self from other in bacterial communities. We develop a live-cell biofilm formation and dispersal assay that allows examination of the individual and combined roles of the two autoinducers in controlling V. cholerae behavior. We show that the quorum-sensing system works as a coincidence detector in which both autoinducers must be present simultaneously for repression of biofilm formation to occur. Within that context, the CAI-1 quorum-sensing pathway is activated when only a few V. cholerae cells are present, whereas the AI-2 pathway is activated only at much higher cell density. The consequence of this asymmetry is that exogenous sources of AI-2, but not CAI-1, contribute to satisfying the coincidence detector to repress biofilm formation and promote dispersal. We propose that V. cholerae uses CAI-1 to verify that some of its kin are present before committing to the high-cell-density quorum-sensing mode, but it is, in fact, the universal autoinducer AI-2, that sets the pace of the V. cholerae quorum-sensing program. This first report of unique roles for the different V. cholerae autoinducers suggests that detection of self fosters a distinct outcome from detection of other.

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A role for rhamnolipid in biofilm dispersion

Biofilms ◽

10.1017/s147905050400119x ◽

2004 ◽

Vol 1 (2) ◽

pp. 91-99 ◽

Cited By ~ 48

Author(s):

S. R. Schooling ◽

U. K. Charaf ◽

D. G. Allison ◽

P. Gilbert

Keyword(s):

Surface Tension ◽

Quorum Sensing ◽

Biofilm Formation ◽

Culture Medium ◽

High Cell Density ◽

Culture Media ◽

Homoserine Lactone ◽

Wild Type ◽

In The Wild ◽

Biofilm Dispersion

Biofilms are often considered as localized zones of high cell density. Quorum sensing provides a means for control of population processes and has been implicated in the regulation of biofilm activities. We present a role for quorum sensing in programmed detachment and dispersal processes. Biofilms of Pseudomonas aeruginosa PAO1 and its isogenic homoserine lactone (HSL) mutant P. aeruginosa PAO-JP2 were grown in batch culture on glass substrata; differences were found in the rate and extent of formation of biofilm. Climax communities were observed for PAO1 at 24 h. These were later accompanied by foaming, a drop in the surface tension of culture media and dispersal of the biofilm, after which no subsequent biofilm accretion occurred. PAO-JP2 cultures reformed biofilm post-detachment and did not foam. Prevention of biofilm reformation in the wild type was related to some component excreted into the culture medium. Rhamnolipid, a biosurfactant regulated by quorum sensing, was detected in PAO1 cultures. When rhamnolipid was added to freshly inoculated substrata, biofilm formation was inhibited. At 20 h, PAO1 biofilms were transferred to medium with added rhamnolipid: biofilm was relatively unaffected. Biofilm events were also studied in medium supplemented with N-butyryl-L-homoserine lactone, which is involved in the regulation of rhamnolipid synthesis. Both strains exhibited similar trends of rapid biofilm formation and dramatic changes in the rate and extent of biofilm accretion. In both cases, there was premature foaming, lowered surface tension and elevated rhamnolipid levels. A role for HSLs in maintenance of biofilm and events leading to dispersion of cells is proposed. This role would encompass dispersion but not necessarily detachment of cells from biofilm and supports a new function for rhamnolipid in pathogenesis, whereby rhamnolipid would promote the dissemination of cells from a nidus of infection.

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Integration of Cyclic di-GMP and Quorum Sensing in the Control ofvpsTandaphAin Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.05167-11 ◽

2011 ◽

Vol 193 (22) ◽

pp. 6331-6341 ◽

Cited By ~ 103

Author(s):

Disha Srivastava ◽

Rebecca C. Harris ◽

Christopher M. Waters

Keyword(s):

Quorum Sensing ◽

Binding Site ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Virulence Gene ◽

Transcriptional Activator ◽

Transcriptional Regulators ◽

Content Type ◽

Virulence Gene Expression ◽

Signaling Systems

Vibrio choleraetransitions between aquatic environmental reservoirs and infection in the gastrointestinal tracts of human hosts. The second-messenger molecule cyclic di-GMP (c-di-GMP) and quorum sensing (QS) are important signaling systems that enableV. choleraeto alternate between these distinct environments by controlling biofilm formation and virulence factor expression. Here we identify a conserved regulatory mechanism inV. choleraethat integrates c-di-GMP and QS to control the expression of two transcriptional regulators:aphA, an activator of virulence gene expression and an important regulator of the quorum-sensing pathway, andvpsT, a transcriptional activator that induces biofilm formation. Surprisingly,aphAexpression was induced by c-di-GMP. Activation of bothaphAandvpsTby c-di-GMP requires the transcriptional activator VpsR, which binds to c-di-GMP. The VpsR binding site at each of these promoters overlaps with the binding site of HapR, the master QS regulator at high cell densities. Our results suggest thatV. choleraecombines information conveyed by QS and c-di-GMP to appropriately respond and adapt to divergent environments by modulating the expression of key transcriptional regulators.

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