scholarly journals Quorum Sensing-1 Signaling of N-hexanoyl-L-Homoserine Lactone Contributes to Virulence in Avian Pathogenic Escherichia Coli

2021 ◽  
Author(s):  
Yang Yang ◽  
Xin Zhang ◽  
Binbin Zhang ◽  
Mingxu Zhou ◽  
Qiangde Duan ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Receptor Gene ◽  
Acid Tolerance ◽  
Acid Resistance ◽  
Homoserine Lactone ◽  
E Coli ◽  
Recombination System ◽  
Luxr Homolog

Abstract Avian pathogenic E. coli (APEC) caused avian colibacillosis is mostly common in poultry industry worldwide. APEC virulence factors lead to pathogenesis and the quorum sensing (QS) system is actively involved in the regulation of these virulence factors. Signaling molecules in QS are known as autoinducers (AIs). In QS-1, E. coli encodes a single LuxR homolog, i.e SdiA, but does not express the LuxI homolog, an acyl-homoserine lactone (AHL) synthase of producing AI-1. Avian pathogenic E. coli (APEC) regulates its virulence genes expression in response to exogenous AHLs, but regulatory mechanisms of AHL and QS-1 are still unknown. This study targeted the APEC CE129 isolate as the reference strain, and the Yersinia enterocolitica yenI gene was expressed into APEC CE129. CE129/pyenI was conferred the ability to produce AHL signal. The CE129 SdiA mutant strain with an in-frame sdiA (AHL receptor) gene deletion was constructed by a λRed recombination system, which lost the ability to sense AHL. AimsThe goal of this study was to explore the function of QS-1 upon virulence and elucidate the regulatory effect of QS-1/AHL signals in the APEC strain.ResultsAdherence and invasion assays revealed that QS-1 affected APEC adherence and survival ability. APEC biofilm formation was also suppressed under C6HSL. Interestingly, APEC exhibited different phenotypes of acid tolerance and flagella expression when compared to enterotoxigenic E. coli or enterohemorrhagic E. coli (ETEC and EHEC, respectively). These findings enhance our understanding of the QS mechanism.ConclusionsQS-1 affected APEC biofilm formation, adhesion, and survival ability, but did not affect bacterial acid resistance (AR) or flagella expression, which were observed in ETEC and EHEC. The findings of this study have laid the foundation for further clarifying the complex mechanism of QS in future investigations on the virulence of APEC.

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 The Plant Pathogen Pantoea ananatis Produces N-Acylhomoserine Lactone and Causes Center Rot Disease of Onion by Quorum Sensing

2007 ◽  
Vol 189 (22) ◽  
pp. 8333-8338 ◽  
Author(s):  
Tomohiro Morohoshi ◽  
Yuta Nakamura ◽  
Go Yamazaki ◽  
Akio Ishida ◽  
Norihiro Kato ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Receptor Gene ◽  
Homoserine Lactone ◽  
Pantoea Ananatis ◽  
Signal Molecule ◽  
Acylhomoserine Lactone ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Rot Disease

ABSTRACT A number of gram-negative bacteria have a quorum-sensing system and produce N-acyl-l-homoserine lactone (AHL) that they use them as a quorum-sensing signal molecule. Pantoea ananatis is reported as a common colonist of wheat heads at ripening and causes center rot of onion. In this study, we demonstrated that P. ananatis SK-1 produced two AHLs, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-(3-oxohexanoyl)-l-homoserine lactone (3-oxo-C6-HSL). We cloned the AHL-synthase gene (eanI) and AHL-receptor gene (eanR) and revealed that the deduced amino acid sequence of EanI/EanR showed high identity to those of EsaI/EsaR from P. stewartii. EanR repressed the ean box sequence and the addition of AHLs resulted in derepression of ean box. Inactivation of the chromosomal eanI gene in SK-1 caused disruption of exopolysaccharide (EPS) biosynthesis, biofilm formation, and infection of onion leaves, which were recovered by adding exogenous 3-oxo-C6-HSL. These results demonstrated that the quorum-sensing system involved the biosynthesis of EPS, biofilm formation, and infection of onion leaves in P. ananatis SK-1.

scholarly journals Role of Quorum Sensing and Antimicrobial Component Production by Serratia plymuthica in Formation of Biofilms, Including Mixed Biofilms with Escherichia coli

2006 ◽  
Vol 72 (11) ◽  
pp. 7294-7300 ◽  
Author(s):  
Pieter Moons ◽  
Rob Van Houdt ◽  
Abram Aertsen ◽  
Kristof Vanoirbeek ◽  
Yves Engelborghs ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Broth Culture ◽  
Confocal Laser ◽  
Wild Type ◽  
Serratia Plymuthica ◽  
E Coli

ABSTRACT We have previously characterized the N-acyl-l-homoserine lactone-based quorum-sensing system of the biofilm isolate Serratia plymuthica RVH1. Here we investigated the role of quorum sensing and of quorum-sensing-dependent production of an antimicrobial compound (AC) on biofilm formation by RVH1 and on the cocultivation of RVH1 and Escherichia coli in planktonic cultures or in biofilms. Biofilm formation of S. plymuthica was not affected by the knockout of splI or splR, the S. plymuthica homologs of the luxI or luxR quorum-sensing gene, respectively, or by the knockout of AC production. E. coli grew well in mixed broth culture with RVH1 until the latter reached 8.5 to 9.5 log CFU/ml, after which the E. coli colony counts steeply declined. In comparison, only a very small decline occurred in cocultures with the S. plymuthica AC-deficient and splI mutants. Complementation with exogenous N-hexanoyl-l-homoserine lactone rescued the wild-type phenotype of the splI mutant. The splR knockout mutant also induced a steep decline of E. coli, consistent with its proposed function as a repressor of quorum-sensing-regulated genes. The numbers of E. coli in 3-day-old mixed biofilms followed a similar pattern, being higher with S. plymuthica deficient in SplI or AC production than with wild-type S. plymuthica, the splR mutant, or the splI mutant in the presence of N-hexanoyl-l-homoserine lactone. Confocal laser scanning microscopic analysis of mixed biofilms established with strains producing different fluorescent proteins showed that E. coli microcolonies were less developed in the presence of RVH1 than in the presence of the AC-deficient mutant.

scholarly journals Inhibition of Quorum Sensing in Pseudomonas aeruginosa by N-Acyl Cyclopentylamides

2007 ◽  
Vol 73 (10) ◽  
pp. 3183-3188 ◽  
Author(s):  
Takenori Ishida ◽  
Tsukasa Ikeda ◽  
Noboru Takiguchi ◽  
Akio Kuroda ◽  
Hisao Ohtake ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Ring Structure ◽  
Response Regulators ◽  
Maximal Inhibition ◽  
Sensing Systems ◽  
Reporter Assays

ABSTRACT N-Octanoyl cyclopentylamide (C8-CPA) was found to moderately inhibit quorum sensing in Pseudomonas aeruginosa PAO1. To obtain more powerful inhibitors, a series of structural analogs of C8-CPA were synthesized and examined for their ability to inhibit quorum sensing in P. aeruginosa PAO1. The lasB-lacZ and rhlA-lacZ reporter assays revealed that the chain length and the ring structure were critical for C8-CPA analogs to inhibit quorum sensing. N-Decanoyl cyclopentylamide (C10-CPA) was found to be the strongest inhibitor, and its concentrations required for half-maximal inhibition for lasB-lacZ and rhlA-lacZ expression were 80 and 90 μM, respectively. C10-CPA also inhibited production of virulence factors, including elastase, pyocyanin, and rhamnolipid, and biofilm formation without affecting growth of P. aeruginosa PAO1. C10-CPA inhibited induction of both lasI-lacZ by N-(3-oxododecanoyl)-l-homoserine lactone (PAI1) and rhlA-lacZ by N-butanoyl-l-homoserine lactone (PAI2) in the lasI rhlI mutant of P. aeruginosa PAO1, indicating that C10-CPA interferes with the las and rhl quorum-sensing systems via inhibiting interaction between their response regulators (LasR and RhlR) and autoinducers.

scholarly journals The Effect of Furanone on Enterotoxigenic Escherichia Coli (ETEC) O139 Transcriptome Was Analyzed Using RNA-seq

2020 ◽  
Author(s):  
Jing-He Li ◽  
Jia-Lin Yu ◽  
Qiang An ◽  
Chun-Lei Zhang ◽  
Peng-Fei Yi
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Enterotoxigenic Escherichia Coli ◽  
Biological Behavior ◽  
Signal Molecules ◽  
Rna Seq ◽  
Safe Food

Abstract Background: In recent years, the effective ingredients of some medicine play an anti-infection role in inhibiting the formation of bacterial virulence factors and biofilm without affecting the growth of bacteria, which can reduce the survival pressure of bacteria and is not easy to develop drug resistance. It is considered to be a better way to control the infection of pathogenic microorganisms. Bacteria can produce signal molecules called auto-inducers (AIs) which can sense the bacteria density change. When auto-inducers accumulate to the threshold, they will regulate the bacteria biological behavior to adapt the changes of environment, including the formation of biofilm, virulence factors and bioluminescence. This is quorum sensing (QS).4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) is a non-halogenated furanone found in strawberries, pineapples and other fruits and widely used as a safe food additive in beverages, ice cream and cigarettes. At present, there are lots of studies about furanone. Previous studies have shown that this kind of compound can compete with Acyl-homoserine lactone (AHL) in binding with its receptors, which inhibits the initiation of quorum sensing system. Results: In recent years, few studies about the transcriptome analysis of the furanone interacting with Enterotoxigenic Escherichia coli (ETEC) were reported. Therefore, we analyzed the effect of furanone on ETEC O139 transcriptome by RNA-seq. The result show that genes related to QS did not change after the interaction of 10μg/ml furanone and ETEC O139, while the expression of some genes related to the pathogenicity of ETEC O139 increased, such as flagellum assembly, biofilm formation and adhesion and so on.Conclusions: 10μg/ml furanone have no influence on QS system, but could contribute to adhesion, invasion, flagellum assembly and biofilm formation of ETEC O139.

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.

Quorum Sensing – A Stratagem for Conquering Multi-Drug Resistant Pathogens

2020 ◽  
Vol 26 ◽  
Author(s):  
Madison Tonkin ◽  
Shama Khan ◽  
Mohmmad Younus Wani ◽  
Aijaz Ahmad
Keyword(s):  
Drug Resistance ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Cell Communication ◽  
Natural Compounds ◽  
Quorum Sensing Inhibitors ◽  
Communication Technique ◽  
Multicellular Organisms ◽  
Chemical Strategies

: Quorum sensing is defined as cell to cell communication between microorganisms, which enables microorganisms to behave as multicellular organisms. Quorum sensing enables many collaborative benefits such as synchronisation of virulence factors and biofilm formation. Both quorum sensing as well as biofilm formation encourage the development of drug resistance in microorganisms. Biofilm formation and quorum sensing are causally linked to each other and play role in the pathogenesis of microorganisms. With the increasing drug resistance against the available antibiotics and antifungal medications, scientists are combining different options to develop new strategies. Such strategies rely on the inhibition of the communication and virulence factors rather than on killing or inhibiting the growth of the microorganisms. This review encompasses the communication technique used by microorganisms, how microorganism resistance is linked to quorum sensing and various chemical strategies to combat quorum sensing and thereby drug resistance. Several compounds have been identified as quorum sensing inhibitors and are known to be effective in reducing resistance as they do not kill the pathogens but rather disrupt their communication. Natural compounds have been identified as anti-quorum sensing agents. However, natural compounds present several related disadvantages. Therefore, the need for the development of synthetic or semi-synthetic compounds has arisen. This review argues that anti-quorum sensing compounds are effective in disrupting quorum sensing and could therefore be effective in reducing microorganism drug resistance.

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.

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