scholarly journals The Burkholderia mallei BmaR3-BmaI3 Quorum-Sensing System Produces and Responds to N-3-Hydroxy-Octanoyl Homoserine Lactone

2008 ◽  
Vol 190 (14) ◽  
pp. 5137-5141 ◽  
Author(s):  
Breck A. Duerkop ◽  
Jake P. Herman ◽  
Ricky L. Ulrich ◽  
Mair E. A. Churchill ◽  
E. Peter Greenberg
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Mallei ◽  
E Coli ◽  
Additional Signal ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Signal Receptors

ABSTRACT Burkholderia mallei has two acyl-homoserine lactone (acyl-HSL) signal generator-receptor pairs and two additional signal receptors, all of which contribute to virulence. We show that B. mallei produces N-3-hydroxy-octanoyl HSL (3OHC8-HSL) but a bmaI3 mutant does not. Recombinant Escherichia coli expressing BmaI3 produces hydroxylated acyl-HSLs, with 3OHC8-HSL being the most abundant compound. In recombinant E. coli, BmaR3 responds to 3OHC8-HSL but not to other acyl-HSLs. These data indicate that the signal for BmaR3-BmaI3 quorum sensing is 3OHC8-HSL.

Genetic and functional diversity of PsyI/PsyR quorum-sensing system in the Pseudomonas syringae complex

2020 ◽  
Author(s):  
Tomohiro Morohoshi ◽  
Akinori Oshima ◽  
Xiaonan Xie ◽  
Nobutaka Someya
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Pseudomonas Syringae ◽  
Dna Sequences ◽  
Homoserine Lactone ◽  
Sensing System ◽  
Sensing Systems ◽  
Quorum Sensing System ◽  
High Level ◽  
Functionally Diverse

Abstract Strains belonging to the Pseudomonas syringae complex often possess quorum-sensing systems that comprise N-acyl-l-homoserine lactone (AHL) synthase (PsyI) and AHL receptors (PsyR). Here, we investigated the diversity of PsyI/PsyR quorum-sensing systems in 630 strains of the P. syringae complex. AHL production was observed in most strains of P. amygdali and P. meliae, and a few strains of P. coronafaciens and P. syringae. The DNA sequences of psyIR and their upstream and downstream regions were categorized into eight types. P. amygdali pv. myricae, P. savastanoi, and P. syringae pv. solidagae, maculicola, broussonetiae, and tomato encoded psyI, but did not produce detectable amounts of AHL. In P. savastanoi, an amino acid substitution (R27S) in PsyI caused defective AHL production. The psyI gene of P. syringae pv. tomato was converted to pseudogenes by frameshift mutations. Escherichia coli harboring psyI genes from P. amygdali pv. myricae, P. syringae pv. solidagae and broussonetiae showed high level of AHL production. Forced expression of functional psyR restored AHL production in P. amygdali pv. myricae and P. syringae pv. solidagae. In conclusion, our study indicates that the PsyI/PsyR quorum-sensing systems in P. syringae strains are genetically and functionally diverse, with diversity being linked to phylogenetic and pathovar classifications.

scholarly journals Insights into the Genome Sequences of an N -Acyl Homoserine Lactone Molecule Producing Two Pseudomonas spp. Isolated from the Arctic

2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Akhilandeswarre Dharmaprakash ◽  
Dinesh Reghunathan ◽  
Krishnakutty C. Sivakumar ◽  
Manoj Prasannakumar ◽  
Sabu Thomas
Keyword(s):  
Quorum Sensing ◽  
Draft Genome ◽  
Homoserine Lactone ◽  
The Arctic ◽  
Acyl Homoserine Lactone ◽  
Cold Environments ◽  
Sensing System ◽  
Quorum Sensing System ◽  
First Time

We report for the first time the draft genome sequence of two psychrotrophic Pseudomonas species, Pseudomonas simiae RGCB 73 and Pseudomonas brenneri RGCB 108, from the Arctic that produce more than one acyl homoserine lactone molecule of varied N -acyl length. The study confirms the presence of a LuxR-LuxI (type) mediated quorum-sensing system in both the Pseudomonas species and enables us to understand the role of quorum sensing in their survival in extremely cold environments.

scholarly journals BIOFILM FORMATION AND QUORUM SENSING ANALYSIS OF UROPATHOGENIC MULTIDRUG RESISTANCE ESCHERICHIA COLI

2021 ◽  
pp. 61-63
Author(s):  
MOHANA PRIYA M. ◽  
G. BHUVANESHWARI
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Retardation Factor ◽  
Clinical Microbiology Laboratory ◽  
Acyl Homoserine Lactone ◽  
Chromatography Method ◽  
E Coli

Objective: Escherichia coli (E. coli) are gram-negative facultative anaerobes which are commonly found in the lower intestine. Biofilm production in E. coli promotes colonization and leads to an increase rate of infections, and such infections may be difficult to treat as they exhibit multidrug resistance (MDR). Methods: 50 strains of uropathogenic E. coli were collected from Clinical Microbiology laboratory at Saveetha medical college and hospital for a time period of 3 mo. Strains were identified by conventional biochemical methods. Biofilm formation and quorum sensing analysis were performed by the Microtitre plate method and Thin Layer Chromatography method (TLC), respectively. Results: In this study, 46 (92%) of E. coli strains were strong, 3(6%) were intermediate and 1(2%) were weak biofilm producers. From TLC analysis, 34 (68%) of the strains produced Acyl Homoserine Lactone molecules. Out of which, 16 isolates were shown unknown analytes of Retardation factor (Rf) value greater than 1. The Rf values identified were 3 unsubstituted C4 (5), 3 unsubstituted C6 (3), 3 oxo C8 (3), 3 oxo C4 (4), 3 oxo C6 (2), 3 oxo C1 (1). Conclusion: In this study, 100% of isolates were biofilm producers. Of which 18 strains produced known Acyl Homoserine Lactone molecules and 16 isolates produced unknown analytes. Thus, quorum sensing molecules plays a major role in biofilm formation.

scholarly journals Inhibition of exoprotease production in Aeromonas hydrophila by rhizome extract of temu lawak (Curcuma xanthorrhiza (Roxb.)

2006 ◽  
Vol 4 (2) ◽  
pp. 45-54
Author(s):  
UMI LESTARI ◽  
ARTINI PANGASTUTI ◽  
ARI SUSILOWATI
Keyword(s):  
Quorum Sensing ◽  
Ethyl Acetate ◽  
Aeromonas Hydrophila ◽  
Ethanol Extract ◽  
Homoserine Lactone ◽  
Sensing System ◽  
Development Of Resistance ◽  
Quorum Sensing System ◽  
Assay Result ◽  
Curcuma Xanthorrhiza

Conventional treatment of infectious diseases is based on compounds that kill or inhibit the growth of bacteria. A major concern with this approach is the frequent development of resistance to antimicrobial compounds. The discovery of communication (quorum sensing system) regulating bacterial virulence opens up ways to control certain bacterial infectious without interfering the growth. The fish pathogen Aeromonas hydrophila produces quorum sensing signal, NButanoyl-L-Homoserine Lactone (C4-HSL). C4-HSL regulates exoprotease synthesis, a virulence factor of A. hydrophila. Expression of exoprotease can be blocked by using quorum sensing inhibitor. The purpose of this study was to investigate the inhibiting effect of Curcuma xanthorrhiza (Roxb.) extract to exoprotease production of A. hydrophila. Extraction was conducted by using n-hexane, ethyl acetate and ethanol. The qualitative exoprotease assay result showed that n-hexane extract of C. xanthorrhiza had not effect on growth and exoprotease production of A. hydrophila. Meanwhile, 4% of ethyl acetate and ethanol extract of C. xanthorrhiza can inhibit exoprotease production without affecting A. hydrophilla growth. The quantitative exoprotease assay result showed that 4% of ethyl acetate and ethanol extract can inhibit the exoprotease production by 93,9% and 95,6%. The growth of A. hydrophila was not affected by this extract.

scholarly journals PqsE Functions Independently of PqsR-Pseudomonas Quinolone Signal and Enhances the rhl Quorum-Sensing System

2008 ◽  
Vol 190 (21) ◽  
pp. 7043-7051 ◽  
Author(s):  
John M. Farrow ◽  
Zoe M. Sund ◽  
Matthew L. Ellison ◽  
Dana S. Wade ◽  
James P. Coleman ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Opportunistic Pathogen ◽  
Homoserine Lactone ◽  
Chronic Infections ◽  
Signaling Systems ◽  
Sensing System ◽  
Pseudomonas Quinolone Signal ◽  
Quorum Sensing System ◽  
Hostile Environments

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that causes both acute and chronic infections in immunocompromised individuals. This gram-negative bacterium produces a battery of virulence factors that allow it to infect and survive in many different hostile environments. The control of many of these virulence factors falls under the influence of one of three P. aeruginosa cell-to-cell signaling systems. The focus of this study, the quinolone signaling system, functions through the Pseudomonas quinolone signal (PQS), previously identified as 2-heptyl-3-hydroxy-4-quinolone. This signal binds to and activates the LysR-type transcriptional regulator PqsR (also known as MvfR), which in turn induces the expression of the pqsABCDE operon. The first four genes of this operon are required for PQS synthesis, but the fifth gene, pqsE, is not. The function of the pqsE gene is not known, but it is required for the production of multiple PQS-controlled virulence factors and for virulence in multiple models of infection. In this report, we show that PqsE can activate PQS-controlled genes in the absence of PqsR and PQS. Our data also suggest that the regulatory activity of PqsE requires RhlR and indicate that a pqsE mutant can be complemented for pyocyanin production by a large excess of exogenous N-butyryl homoserine lactone (C4-HSL). Finally, we show that PqsE enhances the ability of Escherichia coli expressing RhlR to respond to C4-HSL. Overall, our data lead us to conclude that PqsE functions as a regulator that is independent of PqsR and PQS but dependent on the rhl quorum-sensing system.

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