scholarly journals Discovery of Pandoraea pnomenusa RB38 N-acyl homoserine Lactone Synthase (PpnI) and its Complete Genome Sequence Analysis

2015 ◽  
Author(s):  
Kok-Gan Chan ◽  
Robson Ee ◽  
Kah-Yan How ◽  
Siew-Kim Lee ◽  
Wai-Fong Yin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Homoserine Lactone ◽  
Tandem Mass ◽  
Acyl Homoserine Lactone ◽  
Multiple Sequence ◽  
Genome Sequence Analysis ◽  
Luxr Homolog ◽  
Distinct Cluster ◽  
Complete Genome Sequence Analysis ◽  
Phylogenetic Neighbor

In this study, we sequenced the genome of P. pnomenusa RB38 and reported the finding of a pair of cognate luxI/R homologs which we firstly coined as ppnI, which is found adjacent to a luxR homolog, ppnR. An additional orphan luxR homolog, ppnR2 was also discovered. Multiple sequence alignment revealed that PpnI is a distinct cluster of AHL synthase compared to those of its nearest phylogenetic neighbor, Burkholderia spp. When expressed heterologously and analysed using high resolution tandem mass spectrometry, PpnI directs the synthesis of N-octanoylhomoserine lactone (C8-HSL). To our knowledge, this is the first documentation of the luxI/R homologs of the genus of Pandoraea.

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 Nitrite-Oxidizing Bacterium Nitrobacter winogradskyi ProducesN-Acyl-Homoserine Lactone Autoinducers

2015 ◽  
Vol 81 (17) ◽  
pp. 5917-5926 ◽  
Author(s):  
Brett L. Mellbye ◽  
Peter J. Bottomley ◽  
Luis A. Sayavedra-Soto
Keyword(s):  
Mass Spectrometry ◽  
Chemostat Culture ◽  
Rhodopseudomonas Palustris ◽  
Homoserine Lactone ◽  
Amino Acid Sequences ◽  
Acyl Homoserine Lactone ◽  
Dependent Manner ◽  
Content Type ◽  
Genes Encoding ◽  
A Cell

ABSTRACTNitrobacter winogradskyiis a chemolithotrophic bacterium that plays a role in the nitrogen cycle by oxidizing nitrite to nitrate. Here, we demonstrate a functionalN-acyl-homoserine lactone (acyl-HSL) synthase in this bacterium. TheN. winogradskyigenome contains genes encoding a putative acyl-HSL autoinducer synthase (nwi0626,nwiI) and a putative acyl-HSL autoinducer receptor (nwi0627,nwiR) with amino acid sequences 38 to 78% identical to those inRhodopseudomonas palustrisand otherRhizobiales. Expression ofnwiIandnwiRcorrelated with acyl-HSL production during culture.N. winogradskyiproduces two distinct acyl-HSLs,N-decanoyl-l-homoserine lactone (C10-HSL) and a monounsaturated acyl-HSL (C10:1-HSL), in a cell-density- and growth phase-dependent manner, during batch and chemostat culture. The acyl-HSLs were detected by bioassay and identified by ultraperformance liquid chromatography with information-dependent acquisition mass spectrometry (UPLC-IDA-MS). The C=C bond in C10:1-HSL was confirmed by conversion into bromohydrin and detection by UPLC-IDA-MS.

scholarly journals A Burkholderia cenocepacia Orphan LuxR Homolog Is Involved in Quorum-Sensing Regulation

2009 ◽  
Vol 191 (8) ◽  
pp. 2447-2460 ◽  
Author(s):  
Rebecca J. Malott ◽  
Eoin P. O'Grady ◽  
Jessica Toller ◽  
Silja Inhülsen ◽  
Leo Eberl ◽  
...  
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Negative Regulation ◽  
Burkholderia Cenocepacia ◽  
Acyl Homoserine Lactone ◽  
Independent Manner ◽  
Reverse Transcription Pcr ◽  
Luxr Homolog ◽  
Genes Encoding

ABSTRACT Burkholderia cenocepacia utilizes quorum sensing to control gene expression, including the expression of genes involved in virulence. In addition to CepR and CciR, a third LuxR homolog, CepR2, was found to regulate gene expression and virulence factor production. All B. cenocepacia strains examined contained this orphan LuxR homolog, which was not associated with an adjacent N-acyl-homoserine lactone synthase gene. Expression of cepR2 was negatively autoregulated and was negatively regulated by CciR in strain K56-2. Microarray analysis and quantitative reverse transcription-PCR determined that CepR2 did not influence expression of cepIR or cciIR. However, in strain K56-2, CepR2 negatively regulated expression of several known quorum-sensing-controlled genes, including genes encoding zinc metalloproteases. CepR2 exerted positive and negative regulation on genes on three chromosomes, including strong negative regulation of a gene cluster located adjacent to cepR2. In strain H111, which lacks the CciIR quorum-sensing system, CepR2 positively regulated pyochelin production by controlling transcription of one of the operons required for the biosynthesis of the siderophore in an N-acyl-homoserine lactone-independent manner. CepR2 activation of a luxI promoter was demonstrated in a heterologous Escherichia coli host, providing further evidence that CepR2 can function in the absence of signaling molecules. This study demonstrates that the orphan LuxR homolog CepR2 contributes to the quorum-sensing regulatory network in two distinct strains of B. cenocepacia.

scholarly journals Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical IsolateAcinetobacter baumannii

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kok-Gan Chan ◽  
Huey Jia Cheng ◽  
Jian Woon Chen ◽  
Wai-Fong Yin ◽  
Yun Fong Ngeow
Keyword(s):  
Mass Spectrometry ◽  
Quorum Sensing ◽  
Tandem Mass Spectrometry ◽  
Homoserine Lactone ◽  
Multidrug Resistant ◽  
Side Chain ◽  
Tandem Mass ◽  
Mass Spectrometry Detection ◽  
Liquid Chromatography Tandem Mass ◽  
Chain Lengths

ManyProteobacteriacommunicate via production followed by response of quorum sensing molecules, namely,N-acyl homoserine lactones (AHLs). These molecules consist of a lactone moiety withN-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolateA. baumannii4KT was studied. Production of short chain AHL, namely,N-hexanoyl-homoserine lactone (C6-HSL) andN-octanoyl-homoserine lactone (C8-HSL), was detected.

scholarly journals AnN-Acyl Homoserine Lactone Synthase in the Ammonia-Oxidizing Bacterium Nitrosospira multiformis

2013 ◽  
Vol 80 (3) ◽  
pp. 951-958 ◽  
Author(s):  
Jie Gao ◽  
Anzhou Ma ◽  
Xuliang Zhuang ◽  
Guoqiang Zhuang
Keyword(s):  
Regulatory Networks ◽  
Homoserine Lactone ◽  
Great Sensitivity ◽  
Acyl Homoserine Lactone ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Luxr Homolog ◽  
Ammonia Oxidizing Bacterium ◽  
Culture Supernatants ◽  
Long Chain

ABSTRACTThe chemolithoautotrophic bacteriumNitrosospira multiformisis involved in affecting the process of nitrogen cycling. Here we report the existence and characterization of a functional quorum sensing signal synthase inN. multiformis. One gene (nmuI) playing a role in generating a protein with high levels of similarity toN-acyl homoserine lactone (AHL) synthase protein families was identified. Two AHLs (C14-AHL and 3-oxo-C14-AHL) were detected using an AHL biosensor and liquid chromatography-mass spectrometry (LC-MS) whennmuI, producing a LuxI homologue, was introduced intoEscherichia coli. However, by extractingN. multiformisculture supernatants with acidified ethyl acetate, no AHL product was obtained that was capable of activating the biosensor or being detected by LC-MS. According to reverse transcription-PCR, thenmuIgene is transcribed inN. multiformis, and a LuxR homolog (NmuR) in this ammonia-oxidizing strain showed great sensitivity to long-chain AHL signals by solubility assay. A degradation experiment demonstrated that the absence of AHL signals might be attributed to the possible AHL-inactivating activities of this strain. To summarize, an AHL synthase gene (nmuI) acting as a long-chain AHL producer has been found in a chemolithotrophic ammonia-oxidizing microorganism, and the results provide an opportunity to complete the knowledge of the regulatory networks inN. multiformis.

scholarly journals Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2694
Author(s):  
Ling-Pu Liu ◽  
Long-Hui Huang ◽  
Xiao-Tong Ding ◽  
Lin Yan ◽  
Shi-Ru Jia ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Quorum Sensing ◽  
Tandem Mass Spectrometry ◽  
Homoserine Lactone ◽  
Tandem Mass ◽  
Gram Negative ◽  
Sensing Systems ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

scholarly journals Quorum Sensing Activity ofMesorhizobiumsp. F7 Isolated from Potable Water

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Pei-Ling Yong ◽  
Kok-Gan Chan
Keyword(s):  
Mass Spectrometry ◽  
Phylogenetic Analysis ◽  
Potable Water ◽  
Bacterial Isolate ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Triple Quadrupole ◽  
Liquid Chromatography Mass Spectrometry ◽  
16S Rdna Gene ◽  
Microbe Interactions

We isolated a bacterial isolate (F7) from potable water. The strain was identified asMesorhizobiumsp. by 16S rDNA gene phylogenetic analysis and screened forN-acyl homoserine lactone (AHL) production by an AHL biosensor. The AHL profile of the isolate was further analyzed using high resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) which confirmed the production of multiple AHLs, namely,N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL) andN-3-oxo-decanoyl-L-homoserine lactone (3-oxo-C10-HSL). These findings will open the perspective to study the function of these AHLs in plant-microbe interactions.

scholarly journals Quorum-Sensing Signal Synthesis by the Yersinia pestis Acyl-Homoserine Lactone Synthase YspI

2006 ◽  
Vol 188 (2) ◽  
pp. 784-788 ◽  
Author(s):  
J. Paul Kirwan ◽  
Ty A. Gould ◽  
Herbert P. Schweizer ◽  
Scott W. Bearden ◽  
Robert C. Murphy ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Yersinia Pestis ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Liquid Chromatography Mass Spectrometry ◽  
Wild Type ◽  
Physical Chemical ◽  
Signal Synthesis ◽  
Chemical Techniques ◽  
Culture Supernatants

ABSTRACT The acyl-homoserine lactone molecular species (AHLs) produced by the Yersinia pestis AHL synthase YspI were identified by biochemical and physical/chemical techniques. Bioassays of extracts from culture supernatants of the recombinant YspI and wild-type Yersinia pestis showed similar profiles of AHLs. Analysis by liquid chromatography-mass spectrometry revealed that the predominant AHLs were N-3-oxooctanoyl-l-homoserine lactone and N-3-oxo-hexanoyl-l-homoserine lactone.

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