scholarly journals Distribution of Quorum-Sensing Genes in the Burkholderia cepacia Complex

2001 ◽  
Vol 69 (7) ◽  
pp. 4661-4666 ◽  
Author(s):  
E. Lutter ◽  
S. Lewenza ◽  
J. J. Dennis ◽  
M. B. Visser ◽  
P. A. Sokol
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Homoserine Lactone ◽  
Burkholderia Cepacia Complex ◽  
Homoserine Lactones

ABSTRACT The distribution of quorum-sensing genes among strains from seven genomovars of the Burkholderia cepaciacomplex was examined by PCR. cepR and cepI were amplified from B. cepacia genomovars I and III, B. stabilis, and B. vietnamiensis. cepR was also amplified from B. multivorans and B. cepacia genomovar VI. bviIR were amplified from B. vietnamiensis. All genomovars producedN-octanoyl-l-homoserine lactone andN-hexanoyl-l-homoserine lactone.B. vietnamiensis and B. cepacia genomovar VII produced additional N-acyl-l-homoserine lactones.

scholarly journals Potent modulation of the CepR quorum sensing receptor and virulence in a Burkholderia cepacia complex member using non-native lactone ligands

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Betty L. Slinger ◽  
Jacqueline J. Deay ◽  
Josephine R. Chandler ◽  
Helen E. Blackwell
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Homoserine Lactone ◽  
Communication Process ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Bacterial Communication ◽  
Human Infections ◽  
Chemical Strategies

Abstract The Burkholderia cepacia complex (Bcc) is a family of closely related bacterial pathogens that are the causative agent of deadly human infections. Virulence in Bcc species has been shown to be controlled by the CepI/CepR quorum sensing (QS) system, which is mediated by an N-acyl L-homoserine lactone (AHL) signal (C8-AHL) and its cognate LuxR-type receptor (CepR). Chemical strategies to block QS in Bcc members would represent an approach to intercept this bacterial communication process and further delineate its role in infection. In the current study, we sought to identify non-native AHLs capable of agonizing or antagonizing CepR, and thereby QS, in a Bcc member. We screened a library of AHL analogs in cell-based reporters for CepR, and identified numerous highly potent CepR agonists and antagonists. These compounds remain active in a Bcc member, B. multivorans, with one agonist 250-fold more potent than the native ligand C8-AHL, and can affect QS-controlled motility. Further, the CepR antagonists prolong C. elegans survival in an infection model. These AHL analogs are the first reported non-native molecules that both directly modulate CepR and impact QS-controlled phenotypes in a Bcc member, and represent valuable chemical tools to assess the role of QS in Bcc infections.

Quorum sensing in the Burkholderia cepacia complex

2004 ◽  
Vol 155 (4) ◽  
pp. 238-244 ◽  
Author(s):  
Vittorio Venturi ◽  
Arianna Friscina ◽  
Iris Bertani ◽  
Giulia Devescovi ◽  
Claudio Aguilar
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Burkholderia Cepacia Complex

scholarly journals Degradation of N-Acyl-l-Homoserine Lactones by Bacillus cereus in Culture Media and Pork Extract

2007 ◽  
Vol 73 (7) ◽  
pp. 2329-2332 ◽  
Author(s):  
Maria Stella Medina-Martínez ◽  
Mieke Uyttendaele ◽  
Andreja Rajkovic ◽  
Pol Nadal ◽  
Johan Debevere
Keyword(s):  
Quorum Sensing ◽  
Bacillus Cereus ◽  
Yersinia Enterocolitica ◽  
Culture Medium ◽  
Culture Media ◽  
Homoserine Lactone ◽  
Microbial Interaction ◽  
Signal Molecule ◽  
Homoserine Lactones ◽  
Degrading Bacterium

ABSTRACT Degradation of the quorum-sensing signal molecule N-acyl-l-homoserine lactone (AHL) in cocultures was verified with Bacillus cereus and Yersinia enterocolitica in culture medium and in pork extract. Results showed evidence of microbial interaction when the AHL-degrading bacterium and AHL-producing bacterium were cocultured in a food-simulating condition.

scholarly journals Burkholderia pseudomallei, B. thailandensis, and B. ambifaria Produce 4-Hydroxy-2-Alkylquinoline Analogues with a Methyl Group at the 3 Position That Is Required for Quorum-Sensing Regulation

2008 ◽  
Vol 190 (15) ◽  
pp. 5339-5352 ◽  
Author(s):  
Ludovic Vial ◽  
François Lépine ◽  
Sylvain Milot ◽  
Marie-Christine Groleau ◽  
Valérie Dekimpe ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Burkholderia Pseudomallei ◽  
Alkyl Chain ◽  
Quinoline Ring ◽  
Liquid Chromatography Mass Spectrometry ◽  
Methyl Group ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Oxide Group

ABSTRACT 4-Hydroxy-2-alkylquinolines (HAQs), especially 3,4-dihydroxy-2-heptylquinoline (Pseudomonas quinolone signal) and its precursor, 4-hydroxy-2-heptylquinoline, are attracting much attention, mainly because of their role as signaling molecules in Pseudomonas aeruginosa. The pqsABCDE operon is centrally involved in their biosynthesis. The presence of a homologous operon in Burkholderia pseudomallei and B. thailandensis was recently reported. Thus, we have investigated the abilities of 11 Burkholderia species to produce HAQ-like molecules by liquid chromatography/mass spectrometry. We have identified 29 different HAQ derivatives produced by the only three Burkholderia species where a pqsABCDE homologue was found among available sequenced Burkholderia species genomes, including B. ambifaria, a member of the Burkholderia cepacia complex. In contrast with those of P. aeruginosa, Burkholderia HAQs typically bear a methyl group, hence their designation as 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs). We identified three families of HMAQs with a saturated or unsaturated alkyl chain at the 2′ position, in contrast with the 1′ position of P. aeruginosa, including one with an N-oxide group. Furthermore, the operon in these species contains two more genes downstream of the pqsE homologue, resulting in the hmqABCDEFG operon. While the inactivation of hmqA inhibits the production of HMAQs, the methylation of the quinoline ring requires a putative methyltransferase encoded by hmqG. Interestingly, hmqA or hmqG mutations increase the production of acyl homoserine lactones and, consequently, phenotypes under the control of quorum sensing in B. ambifaria: antifungal activity, siderophore production, and proteolytic activity. These results indicate that only HAQs bearing a methyl group (HMAQs) are involved in quorum-sensing regulation.

scholarly journals Identification of Quorum-Sensing-Regulated Genes of Burkholderia cepacia

2003 ◽  
Vol 185 (21) ◽  
pp. 6456-6462 ◽  
Author(s):  
Claudio Aguilar ◽  
Arianna Friscina ◽  
Giulia Devescovi ◽  
Milan Kojic ◽  
Vittorio Venturi
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Regulatory System ◽  
Extracellular Proteins ◽  
Gram Negative Bacteria ◽  
Gene Promoters ◽  
Regulation Of Expression ◽  
Putative Gene ◽  
Homoserine Lactones ◽  
Global Regulatory System

ABSTRACT Quorum sensing is a regulatory mechanism (operating in response to cell density) which in gram-negative bacteria usually involves the production of N-acyl homoserine lactones (HSL). Quorum sensing in Burkholderia cepacia has been associated with the regulation of expression of extracellular proteins and siderophores and also with the regulation of swarming and biofilm formation. In the present study, several quorum-sensing-controlled gene promoters of B. cepacia ATCC 25416 were identified and characterized. A total of 28 putative gene promoters show CepR-C8-HSL-dependent expression, suggesting that quorum sensing in B. cepacia is a global regulatory system.

scholarly journals raiIR Genes Are Part of a Quorum-Sensing Network Controlled by cinI and cinR in Rhizobium leguminosarum

2002 ◽  
Vol 184 (6) ◽  
pp. 1597-1606 ◽  
Author(s):  
F. Wisniewski-Dyé ◽  
J. Jones ◽  
S. R. Chhabra ◽  
J. A. Downie
Keyword(s):  
Quorum Sensing ◽  
Rhizobium Leguminosarum ◽  
Homoserine Lactone ◽  
Major Product ◽  
Homoserine Lactones ◽  
Indigenous Plasmid ◽  
Sensing Systems ◽  
Regulatory Systems ◽  
Normal Expression ◽  
Low Levels

ABSTRACT Analysis of N-acyl-l-homoserine lactones (AHLs) produced by Rhizobium leguminosarum bv. viciae indicated that there may be a network of quorum-sensing regulatory systems producing multiple AHLs in this species. Using a strain lacking a symbiosis plasmid, which carries some of the quorum-sensing genes, we isolated mutations in two genes (raiI and raiR) that are required for production of AHLs. The raiIR genes are located adjacent to dad genes (involved in d-alanine catabolism) on a large indigenous plasmid. RaiR is predicted to be a typical LuxR-type quorum-sensing regulator and is required for raiI expression. The raiR gene was expressed at a low level, possibly from a constitutive promoter, and its expression was increased under the influence of the upstream raiI promoter. Using gene fusions and analysis of AHLs produced, we showed that expression of raiI is strongly reduced in strains carrying mutations in cinI or cinR, genes which determine a higher-level quorum-sensing system that is required for normal expression of raiIR. The product of CinI, N-(3-hydroxy-7-cis tetradecenoyl) homoserine lactone, can induce raiR-dependent raiI expression, although higher levels of expression are induced by other AHLs. Expression of raiI in a strain of Agrobacterium that makes no AHLs resulted in the identification of N-(3-hydroxyoctanoyl)-l-homoserine lactone (3OH,C8-HSL) as the major product of RaiI, although other AHLs that comigrate with N-hexanoyl-, N-heptanoyl-, and N-octanoyl-homoserine lactones were also made at low levels. The raiI gene was strongly induced by 3OH,C8-HSL (the product of RaiI) but could also be induced by other AHLs, suggesting that the raiI promoter can be activated by other quorum-sensing systems within a network of regulation which also involves AHLs determined by genes on the symbiotic plasmid. Thus, the raiIR and cinIR genes are part of a complex regulatory network that influences AHL biosynthesis in R. leguminosarum.

scholarly journals Quorum-Sensing Signals and Quorum-Sensing Genes in Burkholderia vietnamiensis

2002 ◽  
Vol 184 (4) ◽  
pp. 1187-1191 ◽  
Author(s):  
Barbara-Ann Conway ◽  
E. P. Greenberg
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Homoserine Lactone ◽  
Abundant Species ◽  
Open Reading Frame ◽  
Reading Frame ◽  
Burkholderia Vietnamiensis ◽  
Dna Fragment ◽  
Low Levels ◽  
Quorum Sensing Signals

ABSTRACT Acyl-homoserine lactone (acyl-HSL) quorum sensing is common to many Proteobacteria including a clinical isolate of Burkholderia cepacia. The B. cepacia isolate produces low levels of octanoyl-HSL. We have examined an environmental isolate of Burkholderia vietnamiensis. This isolate produced several acyl-HSLs. The most abundant species was decanoyl-HSL. Decanoyl-HSL in B. vietnamiensis cultures reached concentrations in excess of 20 μM. We isolated a B. vietnamiensis DNA fragment containing a gene for the synthesis of decanoyl-HSL (bviI) and an open reading frame that codes for a putative signal receptor (bviR). A B. vietnamiensis bviI mutant did not produce detectable levels of decanoyl-HSL.

scholarly journals Are There Acyl-Homoserine Lactones within Mammalian Intestines?

2012 ◽  
Vol 195 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Matthew C. Swearingen ◽  
Anice Sabag-Daigle ◽  
Brian M. M. Ahmer
Keyword(s):  
Quorum Sensing ◽  
Intestinal Tract ◽  
Homoserine Lactone ◽  
Signaling Molecules ◽  
Content Type ◽  
Homoserine Lactones ◽  
Luxr Homolog ◽  
Intestinal Pathogens ◽  
Mammalian Intestine ◽  
Surprising Finding

ABSTRACTManyProteobacteriaare capable of quorum sensing usingN-acyl-homoserine lactone (acyl-HSL) signaling molecules that are synthesized by LuxI or LuxM homologs and detected by transcription factors of the LuxR family. Most quorum-sensing species have at least one LuxR and one LuxI homolog. However, members of theEscherichia,Salmonella,Klebsiella, andEnterobactergenera possess only a single LuxR homolog, SdiA, and no acyl-HSL synthase. The most obvious hypothesis is that these organisms are eavesdropping on acyl-HSL production within the complex microbial communities of the mammalian intestinal tract. However, there is currently no evidence of acyl-HSLs being produced within normal intestinal communities. A few intestinal pathogens, includingYersinia enterocolitica, do produce acyl-HSLs, andSalmonellacan detect them during infection. Therefore, a more refined hypothesis is that SdiA orthologs are used for eavesdropping on other quorum-sensing pathogens in the host. However, the lack of acyl-HSL signaling among the normal intestinal residents is a surprising finding given the complexity of intestinal communities. In this review, we examine the evidence for and against the possibility of acyl-HSL signaling molecules in the mammalian intestine and discuss the possibility that related signaling molecules might be present and awaiting discovery.

scholarly journals Commonalities and Differences in Regulation of N-Acyl Homoserine Lactone Quorum Sensing in the Beneficial Plant-Associated Burkholderia Species Cluster

2010 ◽  
Vol 76 (13) ◽  
pp. 4302-4317 ◽  
Author(s):  
Zulma Rocío Suárez-Moreno ◽  
Giulia Devescovi ◽  
Mike Myers ◽  
Letícia Hallack ◽  
Lucia Mendonça-Previato ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Homoserine Lactone ◽  
Plant Colonization ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Glumae ◽  
Species Cluster ◽  
Major Species ◽  
Wide Range ◽  
Environmental Adaptations

ABSTRACT The genus Burkholderia includes over 60 species isolated from a wide range of environmental niches and can be tentatively divided into two major species clusters. The first cluster includes pathogens such as Burkholderia glumae, B. pseudomallei, and B. mallei and 17 well-studied species of the Burkholderia cepacia complex. The other recently established cluster comprises at least 29 nonpathogenic species, which in most cases have been found to be associated with plants. It was previously established that Burkholderia kururiensis, a member of the latter cluster, possesses an N-acyl homoserine lactone (AHL) quorum-sensing (QS) system designated “BraI/R,” which is found in all species of the plant-associated cluster. In the present study, two other BraI/R-like systems were characterized in B. xenovorans and B. unamae and were designated the BraI/RXEN and BraI/RUNA systems, respectively. Several phenotypes were analyzed, and it was determined that exopolysaccharide was positively regulated by the BraIR-like system in the species B. kururiensis, B. unamae, and B. xenovorans, highlighting commonality in targets. However, the three BraIR-like systems also revealed differences in targets since biofilm formation and plant colonization were differentially regulated. In addition, a second AHL QS system designated XenI2/R2 and an unpaired LuxR solo protein designated BxeR solo were also identified and characterized in B. xenovorans LB400T. The two AHL QS systems of B. xenovorans are not transcriptionally regulating each other, whereas BxeR solo negatively regulated xenI2. The XenI2/R2 and BxeR solo proteins are not widespread in the Burkholderia species cluster. In conclusion, the present study represents an extensive analysis of AHL QS in the Burkholderia plant-associated cluster demonstrating both commonalities and differences, probably reflecting environmental adaptations of the various species.

scholarly journals Structural determinants driving homoserine lactone ligand selection in thePseudomonas aeruginosaLasR quorum-sensing receptor

2018 ◽  
Vol 116 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Amelia R. McCready ◽  
Jon E. Paczkowski ◽  
Brad R. Henke ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Ligand Binding ◽  
Homoserine Lactone ◽  
Communication Process ◽  
Signal Molecules ◽  
Structural Determinants ◽  
Homoserine Lactones ◽  
Ligand Selectivity ◽  
Ligand Promiscuity

Quorum sensing is a cell–cell communication process that bacteria use to orchestrate group behaviors. Quorum sensing is mediated by signal molecules called autoinducers. Autoinducers are often structurally similar, raising questions concerning how bacteria distinguish among them. Here, we use thePseudomonas aeruginosaLasR quorum-sensing receptor to explore signal discrimination. The cognate autoinducer, 3OC12homoserine lactone (3OC12HSL), is a more potent activator of LasR than other homoserine lactones. However, other homoserine lactones can elicit LasR-dependent quorum-sensing responses, showing that LasR displays ligand promiscuity. We identify mutants that alter which homoserine lactones LasR detects. Substitution at residue S129 decreases the LasR response to 3OC12HSL, while enhancing discrimination against noncognate autoinducers. Conversely, the LasR L130F mutation increases the potency of 3OC12HSL and other homoserine lactones. We solve crystal structures of LasR ligand-binding domains complexed with noncognate autoinducers. Comparison with existing structures reveals that ligand selectivity/sensitivity is mediated by a flexible loop near the ligand-binding site. We show that LasR variants with modified ligand preferences exhibit altered quorum-sensing responses to autoinducers in vivo. We suggest that possessing some ligand promiscuity endows LasR with the ability to optimally regulate quorum-sensing traits.

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