Identification of N-acylated homoserine lactone quorum sensing signals during aromatics biodegradation by Pseudomonas aeruginosa

2008 ◽  
Vol 136 ◽  
pp. S686
Author(s):  
Yang-Chun Yong ◽  
Jian-Jiang Zhong
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Acylated Homoserine Lactone ◽  
Quorum Sensing Signals

scholarly journals Influence of the MexAB-OprM Multidrug Efflux System on Quorum Sensing in Pseudomonas aeruginosa

1998 ◽  
Vol 180 (20) ◽  
pp. 5443-5447 ◽  
Author(s):  
Kelly Evans ◽  
Luciano Passador ◽  
Ramakrishnan Srikumar ◽  
Eric Tsang ◽  
Jonathon Nezezon ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Homoserine Lactone ◽  
Multidrug Efflux ◽  
Efflux System ◽  
Acylated Homoserine Lactone ◽  
Pai 1 ◽  
Multidrug Efflux System

ABSTRACT Pseudomonas aeruginosa nalB mutants which hyperexpress the MexAB-OprM multidrug efflux system produce reduced levels of several extracellular virulence factors known to be regulated by quorum sensing. Such mutants also produce less acylated homoserine lactone autoinducer PAI-1, consistent with an observed reduction inlasI expression. These data suggest that PAI-1 is a substrate for MexAB-OprM, and its resulting exclusion from cells hyperexpressing MexAB-OprM limits PAI-1-dependent activation of lasI and the virulence genes.

scholarly journals Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 712-723 ◽  
Author(s):  
Valérie Dekimpe ◽  
Eric Déziel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Transcriptional Regulator ◽  
Homoserine Lactone ◽  
The Other ◽  
Virulence Determinants ◽  
Late Stationary Phase ◽  
Regulatory Systems ◽  
Specific Factors

Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of QS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C4-homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhlR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C12-HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.

scholarly journals Host modification of a bacterial quorum-sensing signal induces a phenotypic switch in bacterial symbionts

2017 ◽  
Vol 114 (40) ◽  
pp. E8488-E8497 ◽  
Author(s):  
Cleo Pietschke ◽  
Christian Treitz ◽  
Sylvain Forêt ◽  
Annika Schultze ◽  
Sven Künzel ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Bacterial Communities ◽  
Homoserine Lactone ◽  
Innate Immune ◽  
Expression Data ◽  
Phenotypic Switch ◽  
Host Colonization ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Quorum Sensing Signals

Bacterial communities colonize epithelial surfaces of most animals. Several factors, including the innate immune system, mucus composition, and diet, have been identified as determinants of host-associated bacterial communities. Here we show that the early branching metazoan Hydra is able to modify bacterial quorum-sensing signals. We identified a eukaryotic mechanism that enables Hydra to specifically modify long-chain 3-oxo-homoserine lactones into their 3-hydroxy-HSL counterparts. Expression data revealed that Hydra’s main bacterial colonizer, Curvibacter sp., responds differentially to N-(3-hydroxydodecanoyl)-l-homoserine lactone (3OHC12-HSL) and N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL). Investigating the impacts of the different N-acyl-HSLs on host colonization elucidated that 3OHC12-HSL allows and 3OC12-HSL represses host colonization of Curvibacter sp. These results show that an animal manipulates bacterial quorum-sensing signals and that this modification leads to a phenotypic switch in the bacterial colonizers. This mechanism may enable the host to manipulate the gene expression and thereby the behavior of its bacterial colonizers.

scholarly journals Effects of Antibiotics on Quorum Sensing in Pseudomonas aeruginosa

2008 ◽  
Vol 52 (10) ◽  
pp. 3648-3663 ◽  
Author(s):  
Mette E. Skindersoe ◽  
Morten Alhede ◽  
Richard Phipps ◽  
Liang Yang ◽  
Peter O. Jensen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factor ◽  
Dna Microarrays ◽  
Underlying Mechanism ◽  
Homoserine Lactone ◽  
Reverse Transcription Pcr ◽  
Animal Infection ◽  
Beneficial Action ◽  
Severe Infections

ABSTRACT During infection, Pseudomonas aeruginosa employs bacterial communication (quorum sensing [QS]) to coordinate the expression of tissue-damaging factors. QS-controlled gene expression plays a pivotal role in the virulence of P. aeruginosa, and QS-deficient mutants cause less severe infections in animal infection models. Treatment of cystic fibrosis (CF) patients chronically infected with P. aeruginosa with the macrolide antibiotic azithromycin (AZM) has been demonstrated to improve the clinical outcome. Several studies indicate that AZM may accomplish its beneficial action in CF patients by impeding QS, thereby reducing the pathogenicity of P. aeruginosa. This led us to investigate whether QS inhibition is a common feature of antibiotics. We present the results of a screening of 12 antibiotics for their QS-inhibitory activities using a previously described QS inhibitor selector 1 strain. Three of the antibiotics tested, AZM, ceftazidime (CFT), and ciprofloxacin (CPR), were very active in the assay and were further examined for their effects on QS-regulated virulence factor production in P. aeruginosa. The effects of the three antibiotics administered at subinhibitory concentrations were investigated by use of DNA microarrays. Consistent results from the virulence factor assays, reverse transcription-PCR, and the DNA microarrays support the finding that AZM, CFT, and CPR decrease the expression of a range of QS-regulated virulence factors. The data suggest that the underlying mechanism may be mediated by changes in membrane permeability, thereby influencing the flux of N-3-oxo-dodecanoyl-l-homoserine lactone.

The Role of Regulators in the Expression of Quorum-Sensing Signals in Pseudomonas aeruginosa

2003 ◽  
Vol 6 (2) ◽  
pp. 88-100 ◽  
Author(s):  
Magnus G. Fagerlind ◽  
Scott A. Rice ◽  
Patric Nilsson ◽  
Mikael Harlén ◽  
Sally James ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Quorum Sensing Signals

scholarly journals Bacterial populations in the rhizosphere of tobacco plants producing the quorum-sensing signals hexanoyl-homoserine lactone and 3-oxo-hexanoyl-homoserine lactone

2004 ◽  
Vol 51 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Cathy D'Angelo-Picard ◽  
Denis Faure ◽  
Aurélien Carlier ◽  
Stéphane Uroz ◽  
Aurélie Raffoux ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Tobacco Plants ◽  
Bacterial Populations ◽  
Quorum Sensing Signals

scholarly journals Quorum-Sensing Genes in Pseudomonas aeruginosa Biofilms: Their Role and Expression Patterns

2001 ◽  
Vol 67 (4) ◽  
pp. 1865-1873 ◽  
Author(s):  
Teresa R. De Kievit ◽  
Richard Gillis ◽  
Steve Marx ◽  
Chris Brown ◽  
Barbara H. Iglewski
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Fluorescent Protein ◽  
Expression Patterns ◽  
Homoserine Lactone ◽  
Lower Percentage ◽  
Spatial Studies ◽  
Green Fluorescent ◽  
Biofilm Development

ABSTRACT Acylated homoserine lactone molecules are used by a number of gram-negative bacteria to regulate cell density-dependent gene expression by a mechanism known as quorum sensing (QS). InPseudomonas aeruginosa, QS or cell-to-cell signaling controls expression of a number of virulence factors, as well as biofilm differentiation. In this study, we investigated the role played by the las and rhl QS systems during the early stages of static biofilm formation when cells are adhering to a surface and forming microcolonies. These studies revealed a marked difference in biofilm formation between the PAO1 parent and the QS mutants when glucose, but not citrate, was used as the sole carbon source. To further elucidate the contribution of lasI andrhlI to biofilm maturation, we utilized fusions to unstable green fluorescent protein in concert with confocal microscopy to perform real-time temporal and spatial studies of these genes in a flowing environment. During the course of 8-day biofilm development,lasI expression was found to progressively decrease over time. Conversely, rhlI expression remained steady throughout biofilm development but occurred in a lower percentage of cells. Spatial analysis revealed that lasI andrhlI were maximally expressed in cells located at the substratum and that expression decreased with increasing biofilm height. Because QS was shown previously to be involved in biofilm differentiation, these findings have important implications for the design of biofilm prevention and eradication strategies.

Chemical identification of N -acyl homoserine lactone quorum-sensing signals produced by Sinorhizobium meliloti strains in defined medium

2003 ◽  
Vol 180 (6) ◽  
pp. 494-497 ◽  
Author(s):  
Max Teplitski ◽  
Anatol Eberhard ◽  
Matthew R. Gronquist ◽  
Mengsheng Gao ◽  
Jayne B. Robinson ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Sinorhizobium Meliloti ◽  
Homoserine Lactone ◽  
Defined Medium ◽  
Acyl Homoserine Lactone ◽  
Chemical Identification ◽  
Quorum Sensing Signals
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