scholarly journals N-Acyl homoserine lactone-mediated quorum sensing in pathogenic Aeromonas veronii biovar sobria strain 159: Identification of LuxIR homologs

2015 ◽  
Author(s):  
Xin Yue Chan ◽  
Kah Yan How ◽  
Wai Fong Yin ◽  
Kok Gan Chan
Keyword(s):  
Quorum Sensing ◽  
Bacterial Population ◽  
Gene Annotation ◽  
Homoserine Lactone ◽  
Genome Comparison ◽  
Acyl Homoserine Lactone ◽  
Gram Negative Bacteria ◽  
Signalling Molecules ◽  
Aeromonas Veronii ◽  
High Degree

Quorum sensing (QS) is a mechanism that plays important roles in gene expression in response to an expanding bacterial population. In many Gram-negative bacteria, N-acyl homoserine lactone is mainly secreted as the diffusible signalling molecules. This QS system has been shown to control diverse array of virulence and secondary metabolism. Recently, whole genome sequencing of Aeromonas veronii biovar sobria strain 159 was performed. Genome comparison with closely-related Aeromonas species showed that A. veronii strain 159 shares a high degree of genome synteny with A. hydrophila ATCC 7966. A detailed genome analysis and gene annotation led us to the findings that A. veronii strain 159 harbors QS system which relies on its signal generator, AveI and the transcriptional regulator, AveR. This Aeromonas strain was found to secrete N-butanoylacyl homoserine lactone (C4-HSL). Its LuxIR homologs are similar to proteins of LuxIR famililies among Aeromonas species. This study aims to gain further insights into AveIR system and to compare with AhyIR from A. hydrophila ATCC 7966 and AsaIR from A. salmonicida.

scholarly journals N-Acyl homoserine lactone-mediated quorum sensing in pathogenic Aeromonas veronii biovar sobria strain 159: Identification of LuxIR homologs

2015 ◽  
Author(s):  
Xin Yue Chan ◽  
Kah Yan How ◽  
Wai Fong Yin ◽  
Kok Gan Chan
Keyword(s):  
Quorum Sensing ◽  
Bacterial Population ◽  
Gene Annotation ◽  
Homoserine Lactone ◽  
Genome Comparison ◽  
Acyl Homoserine Lactone ◽  
Gram Negative Bacteria ◽  
Signalling Molecules ◽  
Aeromonas Veronii ◽  
High Degree

Quorum sensing (QS) is a mechanism that plays important roles in gene expression in response to an expanding bacterial population. In many Gram-negative bacteria, N-acyl homoserine lactone is mainly secreted as the diffusible signalling molecules. This QS system has been shown to control diverse array of virulence and secondary metabolism. Recently, whole genome sequencing of Aeromonas veronii biovar sobria strain 159 was performed. Genome comparison with closely-related Aeromonas species showed that A. veronii strain 159 shares a high degree of genome synteny with A. hydrophila ATCC 7966. A detailed genome analysis and gene annotation led us to the findings that A. veronii strain 159 harbors QS system which relies on its signal generator, AveI and the transcriptional regulator, AveR. This Aeromonas strain was found to secrete N-butanoylacyl homoserine lactone (C4-HSL). Its LuxIR homologs are similar to proteins of LuxIR famililies among Aeromonas species. This study aims to gain further insights into AveIR system and to compare with AhyIR from A. hydrophila ATCC 7966 and AsaIR from A. salmonicida.

Variations on a Theme: Diverse N-Acyl Homoserine Lactone-Mediated Quorum Sensing Mechanisms in Gram-Negative Bacteria

2006 ◽  
Vol 89 (3-4) ◽  
pp. 167-211 ◽  
Author(s):  
Debra Smith ◽  
Jin-Hong Wang ◽  
Jane E. Swatton ◽  
Peter Davenport ◽  
Bianca Price ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Variations On A Theme

scholarly journals A single point mutation converts a glutaryl-7-aminocephalosporanic acid acylase into an N-acyl-homoserine lactone acylase

2021 ◽  
Author(s):  
Shereen A. Murugayah ◽  
Gary B. Evans ◽  
Joel D. A. Tyndall ◽  
Monica L. Gerth
Keyword(s):  
Single Point ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Site Directed Mutagenesis ◽  
Saturation Mutagenesis ◽  
Single Amino Acid ◽  
Single Point Mutation ◽  
Acyl Homoserine Lactone ◽  
Signalling Molecules ◽  
Single Amino Acid Residue

Abstract Objective To change the specificity of a glutaryl-7-aminocephalosporanic acid acylase (GCA) towards N-acyl homoserine lactones (AHLs; quorum sensing signalling molecules) by site-directed mutagenesis. Results Seven residues were identified by analysis of existing crystal structures as potential determinants of substrate specificity. Site-saturation mutagenesis libraries were created for each of the seven selected positions. High-throughput activity screening of each library identified two variants—Arg255Ala, Arg255Gly—with new activities towards N-acyl homoserine lactone substrates. Structural modelling of the Arg255Gly mutation suggests that the smaller side-chain of glycine (as compared to arginine in the wild-type enzyme) avoids a key clash with the acyl group of the N-acyl homoserine lactone substrate. Conclusions Mutation of a single amino acid residue successfully converted a GCA (with no detectable activity against AHLs) into an AHL acylase. This approach may be useful for further engineering of ‘quorum quenching’ enzymes.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document