Cell Density-dependent Anammox Activity of <i>Candidatus</i> Brocadia sinica Regulated by <i>N</i>-acyl Homoserine Lactone-mediated Quorum Sensing

ABSTRACT During nutrient starvation, Escherichia coli elicits a stringent response involving the ribosome-associated protein RelA. Activation of RelA results in a global change in the cellular metabolism including enhanced expression of the stationary-phase sigma factor RpoS. In the human pathogen Pseudomonas aeruginosa, a complex quorum-sensing circuitry, linked to RpoS expression, is required for cell density-dependent production of many secreted virulence factors, including LasB elastase. Quorum sensing relies on the activation of specific transcriptional regulators (LasR and RhlR) by their corresponding autoinducers (3-oxo-C12-homoserine lactone [HSL] and C4-HSL), which function as intercellular signals. We found that overexpression of relA activated the expression of rpoS in P. aeruginosa and led to premature, cell density-independent LasB elastase production. We therefore investigated the effects of the stringent response on quorum sensing. Both lasR and rhlR gene expression and autoinducer synthesis were prematurely activated during the stringent response induced by overexpression of relA. Premature expression of lasR and rhlR was also observed when relA was overexpressed in a PAO1 rpoSmutant. The stringent response induced by the amino acid analogue serine hydroxamate (SHX) also led to premature production of the 3-oxo-C12-HSL autoinducer. This response to SHX was absent in a PAO1 relA mutant. These findings suggest that the stringent response can activate the two quorum-sensing systems of P. aeruginosa independently of cell density.

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Cell Density-Dependent Starvation Survival ofRhizobium leguminosarum bv. phaseoli: Identification of the Role of an N- Acyl Homoserine Lactone in Adaptation to Stationary-Phase Survival

Journal of Bacteriology ◽

10.1128/jb.181.3.981-990.1999 ◽

1999 ◽

Vol 181 (3) ◽

pp. 981-990 ◽

Cited By ~ 48

Author(s):

Stephen H. Thorne ◽

Huw D. Williams

Keyword(s):

Stationary Phase ◽

Cell Density ◽

Rhizobium Leguminosarum ◽

Homoserine Lactone ◽

Growth Conditions ◽

Acyl Homoserine Lactone ◽

Density Dependent ◽

Extracellular Factor ◽

Stationary Phase Survival ◽

Starvation Survival

ABSTRACT The cell density dependence of stationary-phase survival ofRhizobium leguminosarum has been investigated. Following starvation by exhaustion of carbon or nitrogen, but not of phosphorus, the survival of cultures was dependent on the cell density at entry into stationary phase. High-density cultures survived with little or no loss of viability over a 20-day period in stationary phase. In contrast, low-density cultures lost viability rapidly but consisted of a heterogeneous population, a small fraction of which successfully adapted and eventually formed a stable, surviving population. The threshold density above which the cultures survived successfully in stationary phase was dependent on the growth conditions and the strain used. We took advantage of the fact that R. leguminosarumsurvives poorly following starvation by resuspension in carbon-free medium to demonstrate that cell density-dependent survival was mediated by a component accumulating in the growth medium. The effects of this medium component on survival in resuspension assays could be mimicked by an N-acyl homoserine lactone,N-(3R-hydroxy-7-cis-tetradecanoyl)-l-homoserine lactone, previously demonstrated to have a role in controlling cell density-dependent phenomena in R. leguminosarum. The Sym plasmids pRP2JI and pRL1JI were found to be essential for the production of the extracellular factor, which could also be made inEscherichia coli carrying the cosmid clone pIJ1086 containing a specific region of pRL1JI.

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The BpsIR Quorum-Sensing System of Burkholderia pseudomallei

Journal of Bacteriology ◽

10.1128/jb.187.2.785-790.2005 ◽

2005 ◽

Vol 187 (2) ◽

pp. 785-790 ◽

Cited By ~ 49

Author(s):

Yan Song ◽

Chao Xie ◽

Yong-Mei Ong ◽

Yunn-Hwen Gan ◽

Kim-Lee Chua

Keyword(s):

Quorum Sensing ◽

Cell Density ◽

Burkholderia Pseudomallei ◽

Homoserine Lactone ◽

Positive Regulation ◽

Density Dependent ◽

Sensing System ◽

Quorum Sensing System

ABSTRACT BpsIR, a LuxIR quorum-sensing homolog, is required for optimal expression of virulence and secretion of exoproducts in Burkholderia pseudomallei. Cell density-dependent expression of bpsI and bpsR, the positive regulation of bpsIR expression by BpsR, and the synthesis of N-octanoyl-homoserine lactone (C8HSL) by BpsI are described in this report.

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A single intracellular protein governs the critical transition from an individual to a coordinated population response during quorum sensing: Origins of primordial language

10.1101/074369 ◽

2016 ◽

Cited By ~ 3

Author(s):

Celina Vila-Sanjurjo ◽

Christoph Engwer ◽

Xiaofei Qin ◽

Lea Hembach ◽

Tania Verdía-Cotelo ◽

...

Keyword(s):

Quorum Sensing ◽

Density Dependence ◽

Cell Density ◽

Fluorescence Intensity ◽

Percolation Theory ◽

Bacterial Cell ◽

Cell Communication ◽

Critical Time ◽

Homoserine Lactone ◽

Density Dependent

Quorum sensing (QS) explains a type of bacterial cell-cell communication mediated by exocellular compounds that act as autoinducers (AIs). As such, QS can be considered the most primordial form of language. QS has profound implications for the control of many important traits (e.g.biofilm formation, secretion of virulence factors, etc.). Conceptually, the QS response can be split into its “listening” and “speaking” components,i.e.the power to sense AI levelsvs.the ability to synthesize and release these molecules. By explaining the cell-density dependence of QS behavior as the consequence of the system’s arrival to a threshold AI concentration, models of QS have traditionally assumed a salient role for the “QS speaking” module during bacterial cell-to-cell communication. In this paper, we have provided evidence that challenges this AI-centered view of QS and establishes LuxR-like activators at the center of QS. Our observation that highly coordinated, cell-density dependent responses can occur in the absence of AI production, implies that the ability to launch such responses is engrained within the “QS listening” module. Our data indicates that once a critical threshold of intracellular activator monomers in complex with AI is reached, a highly orchestrated QS response ensues. While displaying a clear cell-density dependence, such response does not strictly require the sensing of population levels by individual cells. We additionally show, bothin vivoandin silico, that despite their synchronous nature, QS responses do not require that all the cells in the population participate in the response. Central to our analysis was the discovery that percolation theory (PT) can be used to mathematically describe QS responses. While groundbreaking, our results are in agreement with and integrate the latest conclusions reached in the field. We explain for the first time, the cell-density-dependent synchronicity of QS responses as the function of a single protein, the LuxR-like activator, capable of coordinating the temporal response of a population of cells in the absence of cell-to-cell communication. Being QS the most primordial form of speech, our results have important implications for the evolution of language in its ancient chemical form.Abbreviations3Dthree dimensionalacwthreshold intracellular concentration of activator moleculesAHLacyl-homoserine lactoneAHLfischN-(3-oxohexanoyl)-L-homoserine lactoneAHLviolN-hexanoyl-DL-homoserine-lactoneAIautoinducera.uarbitrary unitsBMBbromophenol blueCAtrans-cinnamaldehydeFlfluorescence intensityFI/OD600density-normalized fluorescence intensityGFPgreen fluorescent proteinMwmolecular weightPTpercolation theoryQSquorum sensingtcpercolation critical timewtwild type

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The AinS autoinducer synthase and LitR master regulator of quorum sensing regulate N-3-hydroxy-decanoyl-homoserine-lactone production and motility in Aliivibrio wodanis 06/09/139

10.21203/rs.2.10994/v1 ◽

2019 ◽

Author(s):

Amudha Deepalakshmi Maharajan ◽

Hilde Hansen ◽

Nils Peder Willassen

Keyword(s):

Quorum Sensing ◽

Cell Density ◽

Homoserine Lactone ◽

Temperature Tolerance ◽

Dependent Manner ◽

Secretion Systems ◽

Master Regulator ◽

Density Dependent ◽

Ulcer Disease ◽

A Cell

Abstract Background Quorum Sensing (QS) is a cell to cell communication system, in which bacteria synthesize and respond to signaling molecules called autoinducers (AI). QS is cell density dependent and known to be involved in regulating virulence, motility and secretion systems to interact with the host or other bacteria. Aliivibrio wodanis is frequently isolated together with Moritella viscosa from the infected Atlantic salmon during outbreaks of the winter ulcer disease. M. viscosa is the main causative agent of the disease while the presence of A. wodanis is still unclear. It is hypothesized that A. wodanis might influence the progression of winter ulcer. The genome of A. wodanis 06/09/139 encodes two autoinducer synthase genes (ainS and luxS) and a master regulator litR. LitR homologs in other aliivibrios have been shown to regulate several phenotypes in a cell density dependent manner. Moreover, a previous study has shown that A. wodanis 06/09/139 produces only one AHL N-3-hydroxy-decanoyl-homoserine-lactone (3OHC10-HSL). Hence, in this work, we have studied the QS system in A. wodanis 06/09/139 by knocking out QS genes ainS and litR. The effects of the deletions were studied with regard to growth, AHL production and motility at different temperatures. Results By using HPLC-MS/MS, we found that the deletion of ainS in A. wodanis 06/09/139 resulted in the loss of 3OHC10-HSL production. The 3OHC10-HSL production in A. wodanis 06/09/139 increased with increase in cell density and more 3OHC10-HSL was produced at 6°C than at 12, 16 and 20°C. The litR mutant demonstrated a ~20% reduction in the production of 3OHC10-HSL relative to the wild type at the stationary phase. Compared to the wildtype and the ainS mutant strains, the litR mutant resulted in a strain with improved temperature tolerance. The motility in mutants (∆litR and ∆ainS) were significantly higher than that of the wildtype. Conclusions Our study shows that AinS in A. wodanis 06/09/139 is the AHL synthase responsible for 3OHC10-HSL production, where the production is both cell density and temperature dependent. Our data also shows that LitR regulates 3OHC10-HSL production only to a minor extent and both LitR and AinS are negative regulators of motility.

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N-acyl homoserine lactone molecules assisted quorum sensing: effects consequences and monitoring of bacteria talking in real life

Archives of Microbiology ◽

10.1007/s00203-021-02381-9 ◽

2021 ◽

Author(s):

Ömür Acet ◽

Demet Erdönmez ◽

Burcu Önal Acet ◽

Mehmet Odabaşı

Keyword(s):

Quorum Sensing ◽

Real Life ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone

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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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Influence of Glucose Concentrations on Biofilm Formation, Motility, Exoprotease Production, and Quorum Sensing in Aeromonas hydrophila

Journal of Food Protection ◽

10.4315/0362-028x.jfp-12-321 ◽

2013 ◽

Vol 76 (2) ◽

pp. 239-247 ◽

Cited By ~ 51

Author(s):

IQBAL KABIR JAHID ◽

NA-YOUNG LEE ◽

ANNA KIM ◽

SANG-DO HA

Keyword(s):

Quorum Sensing ◽

Aeromonas Hydrophila ◽

Biofilm Formation ◽

Opportunistic Pathogen ◽

Homoserine Lactone ◽

Protease Production ◽

Acyl Homoserine Lactone ◽

Human Pathogen ◽

Initial Biofilm ◽

Motility Inhibition

Aeromonas hydrophila recently has received increased attention because it is opportunistic and a primary human pathogen. A. hydrophila biofilm formation and its control are a major concern for food safety because biofilms are related to virulence. Therefore, we investigated biofilm formation, motility inhibition, quorum sensing, and exoprotease production of this opportunistic pathogen in response to various glucose concentrations from 0.05 to 2.5% (wt/vol). More than 0.05% glucose significantly impaired (P < 0.05) quorum sensing, biofilm formation, protease production, and swarming and swimming motility, whereas bacteria treated with 0.05% glucose had activity similar to that of the control (0% glucose). A stage shift biofilm assay revealed that the addition of glucose (2.5%) inhibited initial biofilm formation but not later stages. However, addition of quorum sensing molecules N-3-butanoyl-DL-homoserine lactone and N-3-hexanoyl homoserine lactone partially restored protease production, indicating that quorum sensing is controlled by glucose concentrations. Thus, glucose present in food or added as a preservative could regulate acyl-homoserine lactone quorum sensing molecules, which mediate biofilm formation and virulence in A. hydrophila.

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Signal Integration in Quorum Sensing Enables Cross-Species Induction of Virulence in Pectobacterium wasabiae

mBio ◽

10.1128/mbio.00398-17 ◽

2017 ◽

Vol 8 (3) ◽

Cited By ~ 13

Author(s):

Rita S. Valente ◽

Pol Nadal-Jimenez ◽

André F. P. Carvalho ◽

Filipe J. D. Vieira ◽

Karina B. Xavier

Keyword(s):

Signal Transduction ◽

Quorum Sensing ◽

Plant Pathogen ◽

Bacterial Species ◽

Homoserine Lactone ◽

Signal Molecules ◽

Acyl Homoserine Lactone ◽

Interspecies Interactions ◽

Major Factors

ABSTRACT Bacterial communities can sense their neighbors, regulating group behaviors in response to cell density and environmental changes. The diversity of signaling networks in a single species has been postulated to allow custom responses to different stimuli; however, little is known about how multiple signals are integrated and the implications of this integration in different ecological contexts. In the plant pathogen Pectobacterium wasabiae (formerly Erwinia carotovora), two signaling networks—the N-acyl homoserine lactone (AHL) quorum-sensing system and the Gac/Rsm signal transduction pathway—control the expression of secreted plant cell wall-degrading enzymes, its major virulence determinants. We show that the AHL system controls the Gac/Rsm system by affecting the expression of the regulatory RNA RsmB. This regulation is mediated by ExpR2, the quorum-sensing receptor that responds to the P. wasabiae cognate AHL but also to AHLs produced by other bacterial species. As a consequence, this level of regulation allows P. wasabiae to bypass the Gac-dependent regulation of RsmB in the presence of exogenous AHLs or AHL-producing bacteria. We provide in vivo evidence that this pivotal role of RsmB in signal transduction is important for the ability of P. wasabiae to induce virulence in response to other AHL-producing bacteria in multispecies plant lesions. Our results suggest that the signaling architecture in P. wasabiae was coopted to prime the bacteria to eavesdrop on other bacteria and quickly join the efforts of other species, which are already exploiting host resources. IMPORTANCE Quorum-sensing mechanisms enable bacteria to communicate through small signal molecules and coordinate group behaviors. Often, bacteria have various quorum-sensing receptors and integrate information with other signal transduction pathways, presumably allowing them to respond to different ecological contexts. The plant pathogen Pectobacterium wasabiae has two N-acyl homoserine lactone receptors with apparently the same regulatory functions. Our work revealed that the receptor with the broadest signal specificity is also responsible for establishing the link between the main signaling pathways regulating virulence in P. wasabiae. This link is essential to provide P. wasabiae with the ability to induce virulence earlier in response to higher densities of other bacterial species. We further present in vivo evidence that this novel regulatory link enables P. wasabiae to join related bacteria in the effort to degrade host tissue in multispecies plant lesions. Our work provides support for the hypothesis that interspecies interactions are among the major factors influencing the network architectures observed in bacterial quorum-sensing pathways. IMPORTANCE Quorum-sensing mechanisms enable bacteria to communicate through small signal molecules and coordinate group behaviors. Often, bacteria have various quorum-sensing receptors and integrate information with other signal transduction pathways, presumably allowing them to respond to different ecological contexts. The plant pathogen Pectobacterium wasabiae has two N-acyl homoserine lactone receptors with apparently the same regulatory functions. Our work revealed that the receptor with the broadest signal specificity is also responsible for establishing the link between the main signaling pathways regulating virulence in P. wasabiae. This link is essential to provide P. wasabiae with the ability to induce virulence earlier in response to higher densities of other bacterial species. We further present in vivo evidence that this novel regulatory link enables P. wasabiae to join related bacteria in the effort to degrade host tissue in multispecies plant lesions. Our work provides support for the hypothesis that interspecies interactions are among the major factors influencing the network architectures observed in bacterial quorum-sensing pathways.

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