scholarly journals Octanoyl-Homoserine Lactone Is the Cognate Signal for Burkholderia mallei BmaR1-BmaI1 Quorum Sensing

2007 ◽  
Vol 189 (14) ◽  
pp. 5034-5040 ◽  
Author(s):  
Breck A. Duerkop ◽  
Ricky L. Ulrich ◽  
E. Peter Greenberg
Keyword(s):  
Quorum Sensing ◽  
Promoter Region ◽  
Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Homoserine Lactones ◽  
E Coli ◽  
Cognate Receptor ◽  
System A ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing Signals

ABSTRACT Acyl-homoserine lactones (HSLs) serve as quorum-sensing signals for many Proteobacteria. Members of the LuxI family of signal generators catalyze the production of acyl-HSLs, which bind to a cognate receptor in the LuxR family of transcription factors. The obligate animal pathogen Burkholderia mallei produces several acyl-HSLs, and the B. mallei genome has four luxR and two luxI homologs, each of which has been established as a virulence factor. To begin to delineate the relevant acyl-HSL signals for B. mallei LuxR homologs, we analyzed the BmaR1-BmaI1 system. A comparison of acyl-HSL profiles from B. mallei ATCC 23344 and a B. mallei bmaI1 mutant indicates that octanoyl-HSL synthesis is BmaI1 dependent. Furthermore, octanoyl-HSL is the predominant acyl-HSL produced by BmaI1 in recombinant Escherichia coli. The synthesis of soluble BmaR1 in recombinant E. coli requires octanoyl-HSL or decanoyl-HSL. Insoluble aggregates of BmaR1 are produced in the presence of other acyl-HSLs and in the absence of acyl-HSLs. The bmaI1 promoter is activated by BmaR1 and octanoyl-HSL, and a 20-bp inverted repeat in the bmaI1 promoter is required for bmaI1 activation. Purified BmaR1 binds to this promoter region. These findings implicate octanoyl-HSL as the signal for BmaR1-BmaI1 quorum sensing and show that octanoyl-HSL and BmaR1 activate bmaI1 transcription.

scholarly journals The GCR1 and GPA1 Participate in Promotion of Arabidopsis Primary Root Elongation Induced by N-Acyl-Homoserine Lactones, the Bacterial Quorum-Sensing Signals

2012 ◽  
Vol 25 (5) ◽  
pp. 677-683 ◽  
Author(s):  
Fang Liu ◽  
Ziriu Bian ◽  
Zhenhua Jia ◽  
Qian Zhao ◽  
Shuishan Song
Keyword(s):  
Quorum Sensing ◽  
Root Elongation ◽  
Primary Root ◽  
Homoserine Lactone ◽  
Collective Behaviors ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Quorum Sensing Signals

Many gram-negative bacteria use N-acyl-homoserine lactones (AHL) as quorum-sensing signals to coordinate their collective behaviors. Accumulating evidence indicates that plants can respond to AHL. However, little is known about the molecular mechanism of plants reacting to these bacterial signals. In this study, we show that the treatment of Arabidopsis roots with N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) resulted in significant root elongation. The genetic analysis revealed that the T-DNA insertional mutants of gcr1, encoding a G-protein-coupled receptor GCR1, were insensitive to 3OC6-HSL or 3OC8-HSL in assays of root growth. The loss-of-function mutants of the sole canonical Gα subunit GPA1 showed no response to AHL promotion of root elongation whereas Gα gain-of-function plants overexpressing either the wild type or a constitutively active version of Arabidopsis Gα exhibited the exaggerated effect on root elongation caused by AHL. Furthermore, the expression of GCR1 and GPA1 were significantly upregulated after plants were contacted with both AHL. Taken together, our results suggest that GCR1 and GPA1 are involved in AHL-mediated elongation of Arabidopsis roots. This provides insight into the mechanism of plant responses to bacterial quorum-sensing signals.

scholarly journals Virulence of Burkholderia mallei Quorum-Sensing Mutants

2013 ◽  
Vol 81 (5) ◽  
pp. 1471-1478 ◽  
Author(s):  
Charlotte Majerczyk ◽  
Loren Kinman ◽  
Tony Han ◽  
Richard Bunt ◽  
E. Peter Greenberg
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Mouse Lung ◽  
Depth Information ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Content Type ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones

ABSTRACTManyProteobacteriause acyl-homoserine lactone-mediated quorum-sensing (QS) to activate specific sets of genes as a function of cell density. QS often controls the virulence of pathogenic species, and in fact a previous study indicated that QS was important forBurkholderia malleimouse lung infections. To gain in-depth information on the role of QS inB. malleivirulence, we constructed and characterized a mutant ofB. malleistrain GB8 that was unable to make acyl-homoserine lactones. The QS mutant showed virulence equal to that of its wild-type parent in an aerosol mouse infection model, and growth in macrophages was indistinguishable from that of the parent strain. Furthermore, we assessed the role of QS inB. malleiATCC 23344 by constructing and characterizing a mutant strain producing AiiA, a lactonase enzyme that degrades acyl-homoserine lactones. Although acyl-homoserine lactone levels in cultures of this strain are very low, it showed full virulence. Contrary to the previous report, we conclude that QS is not required for acuteB. malleiinfections of mice. QS may be involved in some stage of chronic infections in the natural host of horses, or the QS genes may be remnants of the QS network inB. pseudomalleifrom which this host-adapted pathogen evolved.

scholarly journals Reversible Acyl-Homoserine Lactone Binding to Purified Vibrio fischeri LuxR Protein

2004 ◽  
Vol 186 (3) ◽  
pp. 631-637 ◽  
Author(s):  
M. L. Urbanowski ◽  
C. P. Lostroh ◽  
E. P. Greenberg
Keyword(s):  
Quorum Sensing ◽  
Promoter Region ◽  
Vibrio Fischeri ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
E Coli ◽  
High Affinity ◽  
Founding Member ◽  
Luxr Homolog

ABSTRACT The Vibrio fischeri LuxR protein is the founding member of a family of acyl-homoserine lactone-responsive quorum-sensing transcription factors. Previous genetic evidence indicates that in the presence of its quorum-sensing signal, N-(3-oxohexanoyl) homoserine lactone (3OC6-HSL), LuxR binds to lux box DNA within the promoter region of the luxI gene and activates transcription of the luxICDABEG luminescence operon. We have purified LuxR from recombinant Escherichia coli. Purified LuxR binds specifically and with high affinity to DNA containing a lux box. This binding requires addition of 3OC6-HSL to the assay reactions, presumably forming a LuxR-3OC6-HSL complex. When bound to the lux box at the luxI promoter in vitro, LuxR-3OC6-HSL enables E. coli RNA polymerase to initiate transcription from the luxI promoter. Unlike the well-characterized LuxR homolog TraR in complex with its signal (3-oxo-octanoyl-HSL), the LuxR-30C6-HSL complex can be reversibly inactivated by dilution, suggesting that 3OC6-HSL in the complex is not tightly bound and is in equilibrium with the bulk solvent. Thus, although LuxR and TraR both bind 3-oxoacyl-HSLs, the binding is qualitatively different. The differences have implications for the ways in which these proteins respond to decreases in signal concentrations or rapid drops in population density.

scholarly journals Metabolism of Acyl-Homoserine Lactone Quorum-Sensing Signals by Variovorax paradoxus

2000 ◽  
Vol 182 (24) ◽  
pp. 6921-6926 ◽  
Author(s):  
Jared R. Leadbetter ◽  
E. P. Greenberg
Keyword(s):  
Energy Source ◽  
Nitrogen Sources ◽  
Homoserine Lactone ◽  
Sole Source ◽  
Acyl Homoserine Lactone ◽  
Homoserine Lactones ◽  
Variovorax Paradoxus ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing Signals ◽  
Sole Energy

ABSTRACT Acyl-homoserine lactones (acyl-HSLs) serve as dedicated cell-to-cell signaling molecules in many species of the classProteobacteria. We have addressed the question of whether these compounds can be degraded biologically. A motile, rod-shaped bacterium was isolated from soil based upon its ability to utilizeN-(3-oxohexanoyl)-l-homoserine lactone as the sole source of energy and nitrogen. The bacterium was classified as a strain of Variovorax paradoxus. TheV. paradoxus isolate was capable of growth on all of the acyl-HSLs tested. The molar growth yields correlated with the length of the acyl group. HSL, a product of acyl-HSL metabolism, was used as a nitrogen source, but not as an energy source. Cleavage and partial mineralization of the HSL ring were demonstrated by using radiolabeled substrate. This study indicates that some strains of V. paradoxus degrade and grow on acyl-HSL signals as the sole energy and nitrogen sources. This study provides clues about the metabolic pathway of acyl-HSL degradation by V. paradoxus.

scholarly journals LuxR Solos in the Plant Endophyte Kosakonia sp. Strain KO348

2020 ◽  
Vol 86 (13) ◽  
Author(s):  
Susan Mosquito ◽  
Xianfa Meng ◽  
Giulia Devescovi ◽  
Iris Bertani ◽  
Alexander M. Geller ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
The Other ◽  
The Novel ◽  
Homoserine Lactones ◽  
Interkingdom Signaling ◽  
Promoter Studies ◽  
Quorum Sensing Signals ◽  
Target Promoter ◽  
Plant Compounds

ABSTRACT Endophytes are microorganisms that live inside plants and are often beneficial for the host. Kosakonia is a novel bacterial genus that includes several species that are diazotrophic and plant associated. This study revealed two quorum sensing-related LuxR solos, designated LoxR and PsrR, in the plant endophyte Kosakonia sp. strain KO348. LoxR modeling and biochemical studies demonstrated that LoxR binds N-acyl homoserine lactones (AHLs) in a promiscuous way. PsrR, on the other hand, belongs to the subfamily of plant-associated-bacterium (PAB) LuxR solos that respond to plant compounds. Target promoter studies as well as modeling and phylogenetic comparisons suggest that PAB LuxR solos are likely to respond to different plant compounds. Finally, LoxR is involved in the regulation of T6SS and PsrR plays a role in root endosphere colonization. IMPORTANCE Cell-cell signaling in bacteria allows a synchronized and coordinated behavior of a microbial community. LuxR solos represent a subfamily of proteins in proteobacteria which most commonly detect and respond to signals produced exogenously by other microbes or eukaryotic hosts. Here, we report that a plant-beneficial bacterial endophyte belonging to the novel genus of Kosakonia possesses two LuxR solos; one is involved in the detection of exogenous N-acyl homoserine lactone quorum sensing signals and the other in detecting a compound(s) produced by the host plant. These two Kosakonia LuxR solos are therefore most likely involved in interspecies and interkingdom signaling.

scholarly journals Characterization of a Phosphotriesterase-Like Lactonase fromSulfolobus solfataricusand Its Immobilization for Disruption of Quorum Sensing

2010 ◽  
Vol 77 (4) ◽  
pp. 1181-1186 ◽  
Author(s):  
Filomena S. W. Ng ◽  
Daniel M. Wright ◽  
Stephen Y. K. Seah
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Acyl Chain ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Homoserine Lactones ◽  
Specificity Constant ◽  
Chain Lengths ◽  
Quorum Sensing Signals

ABSTRACTSsoPox, a bifunctional enzyme with organophosphate hydrolase andN-acyl homoserine lactonase activities from the hyperthermophilic archaeonSulfolobus solfataricus, was overexpressed and purified from recombinantPseudomonas putidaKT2440 with a yield of 9.4 mg of protein per liter of culture. The enzyme has a preference forN-acyl homoserine lactones (AHLs) with acyl chain lengths of at least 8 carbon atoms, mainly due to lowerKmvalues for these substrates. The highest specificity constant obtained was forN-3-oxo-decanoyl homoserine lactone (kcat/Km= 5.5 × 103M−1·s−1), but SsoPox can also degradeN-butyryl homoserine lactone (C4-HSL) andN-oxo-dodecanoyl homoserine lactone (oxo-C12-HSL), which are important for quorum sensing in ourPseudomonas aeruginosamodel system. WhenP. aeruginosaPAO1 cultures were grown in the presence of SsoPox-immobilized membranes, the production of C4-HSL- and oxo-C12-HSL-regulated virulence factors, elastase, protease, and pyocyanin were significantly reduced. This is the first demonstration that immobilized quorum-quenching enzymes can be used to attenuate the production of virulence factors controlled by quorum-sensing signals.

scholarly journals Evidence for Acyl Homoserine Lactone Signal Production in Bacteria Associated with Marine Sponges

2004 ◽  
Vol 70 (7) ◽  
pp. 4387-4389 ◽  
Author(s):  
Michael W. Taylor ◽  
Peter J. Schupp ◽  
Harriet J. Baillie ◽  
Timothy S. Charlton ◽  
Rocky de Nys ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Bacterial Colonization ◽  
Homoserine Lactone ◽  
Marine Sponges ◽  
Acyl Homoserine Lactone ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Signal Production ◽  
First Time ◽  
Quorum Sensing Signals

ABSTRACT We report for the first time the production of acyl homoserine lactones (AHLs) by bacteria associated with marine sponges. Given the involvement of AHLs in bacterial colonization of many higher organisms, we speculate that such quorum sensing signals could play a part in interactions between sponges and the dense bacterial communities living within them.

Inactivation of bacterial quorum sensing signals N-acyl homoserine lactones is widespread in yeasts

2018 ◽  
Vol 122 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Ana Carolina del V. Leguina ◽  
Carolina Nieto ◽  
Hipólito F. Pajot ◽  
Elisa V. Bertini ◽  
Walter Mac Cormack ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Quorum Sensing Signals

scholarly journals Long-Chain Acyl-Homoserine Lactone Quorum-Sensing Regulation of Rhodobacter capsulatus Gene Transfer Agent Production

2002 ◽  
Vol 184 (23) ◽  
pp. 6515-6521 ◽  
Author(s):  
Amy L. Schaefer ◽  
Terumi A. Taylor ◽  
J. Thomas Beatty ◽  
E. P. Greenberg
Keyword(s):  
Gene Transfer ◽  
Quorum Sensing ◽  
Rhodobacter Capsulatus ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Chain Acyl ◽  
Gene Transfer Agent ◽  
Long Chain

ABSTRACT Many proteobacteria use acyl-homoserine lactones as quorum-sensing signals. Traditionally, biological detection systems have been used to identify bacteria that produce acyl-homoserine lactones, although the specificities of these detection systems can limit discovery. We used a sensitive approach that did not require a bioassay to detect production of long-acyl-chain homoserine lactone production by Rhodobacter capsulatus and Paracoccus denitrificans. These long-chain acyl-homoserine lactones are not readily detected by standard bioassays. The most abundant acyl-homoserine lactone was N-hexadecanoyl-homoserine lactone. The long-chain acyl-homoserine lactones were concentrated in cells but were also found in the culture fluid. An R. capsulatus gene responsible for long-chain acyl-homoserine lactone synthesis was identified. A mutation in this gene, which we named gtaI, resulted in decreased production of the R. capsulatus gene transfer agent, and gene transfer agent production was restored by exogenous addition of N-hexadecanoyl-homoserine lactone. Thus, long-chain acyl-homoserine lactones serve as quorum-sensing signals to enhance genetic exchange in R. capsulatus.

Sign in / Sign up

Export Citation Format

Share Document