Acyl-Homoserine Lactone-Based Quorum Sensing in Members of the Marine Bacterial Roseobacter Clade: Complex Cell-to-Cell Communication Controls Multiple Physiologies

2016 ◽  
pp. 225-233 ◽  
Author(s):  
Alison Buchan ◽  
April Mitchell ◽  
W. Nathan Cude ◽  
Shawn Campagna
Keyword(s):  
Quorum Sensing ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Complex Cell ◽  
Roseobacter Clade

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

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.

scholarly journals Acyl-Homoserine Lactone Quorum Sensing in the Roseobacter Clade

2014 ◽  
Vol 15 (1) ◽  
pp. 654-669 ◽  
Author(s):  
Jindong Zan ◽  
Yue Liu ◽  
Clay Fuqua ◽  
Russell Hill
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Roseobacter Clade

scholarly journals ThePseudomonas aeruginosaOrphan Quorum Sensing Signal Receptor QscR Regulates Global Quorum Sensing Gene Expression by Activating a Single Linked Operon

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Fengming Ding ◽  
Ken-Ichi Oinuma ◽  
Nicole E. Smalley ◽  
Amy L. Schaefer ◽  
Omar Hamwy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Transcription Factor ◽  
Quorum Sensing ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Null Mutant ◽  
Content Type ◽  
Single Operon

ABSTRACTPseudomonas aeruginosauses two acyl-homoserine lactone signals and two quorum sensing (QS) transcription factors, LasR and RhlR, to activate dozens of genes. LasR responds toN-3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and RhlR toN-butanoyl-homoserine lactone (C4-HSL). There is a thirdP. aeruginosaacyl-homoserine-lactone-responsive transcription factor, QscR, which acts to dampen or delay activation of genes by LasR and RhlR by an unknown mechanism. To better understand the role of QscR inP. aeruginosaQS, we performed a chromatin immunoprecipitation analysis, which showed this transcription factor bound the promoter of only a single operon of three genes linked toqscR, PA1895 to PA1897. Other genes that appear to be regulated by QscR in transcriptome studies were not direct targets of QscR. Deletion of PA1897 recapitulates the early QS activation phenotype of a QscR-null mutant, and the phenotype of a QscR-null mutant was complemented by PA1895-1897 but not by PA1897 alone. We conclude that QscR acts to modulate quorum sensing through regulation of a single operon, apparently raising the QS threshold of the population and providing a “brake” on QS autoinduction.IMPORTANCEQuorum sensing, a cell-cell communication system, is broadly distributed among bacteria and is commonly used to regulate the production of shared products. An important consequence of quorum sensing is a delay in production of certain products until the population density is high. The bacteriumPseudomonas aeruginosahas a particularly complicated quorum sensing system involving multiple signals and receptors. One of these receptors, QscR, downregulates gene expression, unlike the other receptors inP. aeruginosa. QscR does so by inducing the expression of a single operon whose function provides an element of resistance to a population reaching a quorum. This finding has importance for design of quorum sensing inhibitory strategies and can also inform design of synthetic biological circuits that use quorum sensing receptors to regulate gene expression.

scholarly journals N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

2021 ◽  
Vol 22 (14) ◽  
pp. 7565
Author(s):  
Kyungho Woo ◽  
Dong Ho Kim ◽  
Man Hwan Oh ◽  
Ho Sung Park ◽  
Chul Hee Choi
Keyword(s):  
Bone Marrow ◽  
Quorum Sensing ◽  
Deletion Mutant ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Host Responses ◽  
Wild Type ◽  
Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

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

2013 ◽  
Vol 76 (2) ◽  
pp. 239-247 ◽  
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.

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

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
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.

scholarly journals LuxR- and LuxI-Type Quorum-Sensing Circuits Are Prevalent in Members of the Populus deltoides Microbiome

2013 ◽  
Vol 79 (18) ◽  
pp. 5745-5752 ◽  
Author(s):  
Amy L. Schaefer ◽  
Colin R. Lappala ◽  
Ryan P. Morlen ◽  
Dale A. Pelletier ◽  
Tse-Yuan S. Lu ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Populus Deltoides ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Bacterial Isolates ◽  
Content Type ◽  
Eastern Cottonwood ◽  
Bacterial Signaling ◽  
Signal Production ◽  
Plant Signals

ABSTRACTWe are interested in the root microbiome of the fast-growing Eastern cottonwood tree,Populus deltoides. There is a large bank of bacterial isolates fromP. deltoides, and there are 44 draft genomes of bacterial endophyte and rhizosphere isolates. As a first step in efforts to understand the roles of bacterial communication and plant-bacterial signaling inP. deltoides, we focused on the prevalence of acyl-homoserine lactone (AHL) quorum-sensing-signal production and reception in members of theP. deltoidesmicrobiome. We screened 129 bacterial isolates for AHL production using a broad-spectrum bioassay that responds to many but not all AHLs, and we queried the available genome sequences of microbiome isolates for homologs of AHL synthase and receptor genes. AHL signal production was detected in 40% of 129 strains tested. Positive isolates included members of theAlpha-,Beta-, andGammaproteobacteria. Members of theluxIfamily of AHL synthases were identified in 18 of 39 proteobacterial genomes, including genomes of some isolates that tested negative in the bioassay. Members of theluxRfamily of transcription factors, which includes AHL-responsive factors, were more abundant thanluxIhomologs. There were 72 in the 39 proteobacterial genomes. Some of theluxRhomologs appear to be members of a subfamily of LuxRs that respond to as-yet-unknown plant signals rather than bacterial AHLs. Apparently, there is a substantial capacity for AHL cell-to-cell communication in proteobacteria of theP. deltoidesmicrobiota, and there are alsoProteobacteriawith LuxR homologs of the type hypothesized to respond to plant signals or cues.

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