scholarly journals A Quorum-Sensing Inhibitor Strain of Vibrio alginolyticus Blocks Qs-Controlled Phenotypes in Chromobacterium violaceum and Pseudomonas aeruginosa

Marine Drugs ◽  
2019 ◽  
Vol 17 (9) ◽  
pp. 494 ◽  
Author(s):  
José Carlos Reina ◽  
Ignacio Pérez-Victoria ◽  
Jesús Martín ◽  
Inmaculada Llamas
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Fermentation Broth ◽  
Vibrio Alginolyticus ◽  
Chromobacterium Violaceum ◽  
Rrna Gene ◽  
Sea Anemones ◽  
Quorum Sensing Inhibitor

The cell density-dependent mechanism, quorum sensing (QS), regulates the expression of virulence factors. Its inhibition has been proposed as a promising new strategy to prevent bacterial pathogenicity. In this study, 827 strains from the microbiota of sea anemones and holothurians were screened for their ability to produce quorum-sensing inhibitor (QSI) compounds. The strain M3-10, identified as Vibrio alginolyticus by 16S rRNA gene sequencing, as well as ANIb and dDDH analyses, was selected for its high QSI activity. Bioassay-guided fractionation of the cell pellet extract from a fermentation broth of strain M3-10, followed by LC–MS and NMR analyses, revealed tyramine and N-acetyltyramine as the active compounds. The QS inhibitory activity of these molecules, which was confirmed using pure commercially available standards, was found to significantly inhibit Chromobacterium violaceum ATCC 12472 violacein production and virulence factors, such as pyoverdine production, as well as swarming and twitching motilities, produced by Pseudomonas aeruginosa PAO1. This constitutes the first study to screen QSI-producing strains in the microbiota of anemones and holothurians and provides an insight into the use of naturally produced QSI as a possible strategy to combat bacterial infections.

Amphypterygium adstringens Anacardic Acid Mixture Inhibits Quorum Sensing-controlled Virulence Factors of Chromobacterium violaceum and Pseudomonas aeruginosa

2013 ◽  
Vol 44 (7) ◽  
pp. 488-494 ◽  
Author(s):  
Israel Castillo-Juárez ◽  
Rodolfo García-Contreras ◽  
Norma Velázquez-Guadarrama ◽  
Marcos Soto-Hernández ◽  
Mariano Martínez-Vázquez
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Chromobacterium Violaceum ◽  
Anacardic Acid ◽  
Acid Mixture

scholarly journals Production of Quorum Sensing Inhibitors in Growing Onion Bulbs Infected with Pseudomonas aeruginosa E (HQ324110)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mohamed H. Abd-Alla ◽  
Shymaa R. Bashandy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Bacterial Growth ◽  
Myristic Acid ◽  
Bacterial Infections ◽  
Strong Support ◽  
New Approach ◽  
Onion Bulbs ◽  
Quorum Sensing Inhibitors

Eighteen organic compounds were present in growing onion bulbs cultivar Giza 6 infected with P. aeruginosa, but only fourteen of them are present in dry infected onion bulbs; however, four compounds were missing in dry onion. The missing compounds in dry infected onion bulbs are pantolactone, 4,5-dihydro-4,5-dimethylfuran-2(3H)-one, myristic acid, and linoleic acid. All of them were detected in growing onion (living cell) during Pseudomonas aeruginosa infection, and it is hypothesized that it may be produced by plants and act as defence system. Pantolactone and myristic acid were selected to explore their effects on growth and virulence factors of Pseudomonas aeruginosa. Exogenous application of pantolactone and myristic acid significantly inhibited pyocyanin production, protease, and lipase and polygalacturonase activity but did not have any significant effects on bacterial growth. The inhibition of virulence factors without reduction in bacterial growth may be providing strong support that these chemical molecules are general quorum sensing inhibitors than an antibacterial effect. Disruption of quorum sensing of pathogen indicates that this new approach has potential in fighting bacterial infections in human and plants.

scholarly journals Traditional Chinese Medicine Tanreqing Inhibits Quorum Sensing Systems in Pseudomonas aeruginosa

2020 ◽  
Vol 11 ◽  
Author(s):  
Weifeng Yang ◽  
Qing Wei ◽  
Qian Tong ◽  
Kaiyu Cui ◽  
Gaiying He ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Cell Communication ◽  
Opportunistic Pathogen ◽  
Communication Process ◽  
Phenotypic Analysis

Pseudomonas aeruginosa is an opportunistic pathogen that can infect a wide variety of hosts including humans, plants, and animals. The production of virulence factors is the determinant of the infection paradigm and is under orchestrated regulation via cell-to-cell communication process called quorum sensing (QS). To disable QS circuits and prevent bacterial infections, a large battery of anti-QS agents, particularly from traditional Chinese medicine have been developed. Here, we used P. aeruginosa as a model microorganism to investigate the effect of traditional Chinese medicine Tanreqing (TRQ) formula on bacterial pathogenicity. Phenotypic analysis showed that TRQ treatment could completely inhibit the production of phenazine pyocyanin and moderately inhibit the production of virulence factors such as rhamnolipids, elastase, and alkaline protease. Further transcriptomic analyses revealed that TRQ treatment could significantly attenuate the expression of QS-regulated genes in P. aeruginosa and TRQ-treated P. aeruginosa regulon shared a large overlap with QS regulon. Component contribution to QS inhibition shed light on the indispensable role of all five components in TRQ formula. Further genetic analysis indicated that upstream regulators of QS systems, including two-component systems GacS/GacA and PprA/PprB, were both inhibited by TRQ treatment. Finally, our TRQ formula could efficiently protect Caenorhabditis elegans from killing by P. aeruginosa. Altogether, we have proved TRQ formula as an effective and specific agent to attenuate bacterial virulence and combat bacterial infections.

scholarly journals Evaluation of Anti-quorum Sensing Potential of Saraca asoca (Family Caesalpiniaceae) against Chromobacterium violaceum and Pseudomonas aeruginosa PA01

2021 ◽  
pp. 71-82
Author(s):  
B. S. Paliya ◽  
J. Mathew ◽  
B. N. Singh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Test Sample ◽  
Stem Bark ◽  
Chromobacterium Violaceum ◽  
Broth Culture ◽  
Bark Extract ◽  
Swarming Motility ◽  
Saraca Asoca

Aim: The present study was performed to evaluate the anti-quorum sensing (QS) potential of traditional medicinal herb Saracaasoca (family Caesalpiniaceae) stem bark extract against Chromobacterium violaceum and Pseudomonas aeruginosa PA01. Study Design: First, the test sample (bark extract) was screened for anti-QS activity. Then systematic in-vitro and biochemical tests were performed to evaluate the effect of the test sample on the QS mediated virulence factors. Place and Duration of Study: All the experimental works were performed in Lab 311, pharmacology division, CSIR-NBRI Lucknow from June 2019 to October 2019. Methodology: The samples of Saraca asoca stem bark were washed, dried and extracted using 70% methanol. The minimum inhibitory concentration (MIC) of the prepared Sarca asoca bark extract was determined using the Alamar blue assay, and the anti-QS activity was screened using standard agar overlay method against CV 12472 at subinhibitory concentrations 100, 200 and 300 µg (< MIC value). SAE effect on biofilms formation was assessed by growing biofilms on glass slides in a static culture of PA01. Anti-virulence effect of SAE on the production of QS-regulated virulence factors such as Pyocyanin, proteases, elastases, rhamnolipid and alginate in Pseudomonas aeruginosa was determined using the supernatant of a 24 hours old broth culture of PA01 supplemented with SAE. Using the agar plate technique, the swimming and swarming motility assays were conducted on 0.3% and 0.5% agar plates respectively. One-way ANOVA was used to analyze the data, presented as mean ± SD (standard deviation) of three independent experiments. Results: Preliminary screening results showed significant QS inhibition against CV 12472 in an agar overlay disk diffusion assay in a concentration-dependent manner. Data from the biofilm assay showed loose, distorted, irregular PA01 biofilm formation at 200 µg (48%) and 300 µg (65%). SAE caused a significant drop in virulence factor production, with maximum reduction in pyocyanin (58%), proteases (67%), elastases (52%), rhamnolipid (53%), and alginate (44%) observed at 300 µg concentration. At SAE sub-lethal concentrations (200 and 300 µg), both the swimming and swarming motility of PA01 were significantly inhibited. Conclusions: The present study demonstrates the broad-spectrum anti-QS potential of SAE, reported for the first time, suggesting that SAE could be considered as an alternative herbal source to develop antimicrobial agents which can be either solitary or synergistically with conventional antimicrobial drugs.

scholarly journals Pseudomonas aeruginosa PA80 is a cystic fibrosis isolate deficient in RhlRI quorum sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syed A. K. Shifat Ahmed ◽  
Michelle Rudden ◽  
Sabrina M. Elias ◽  
Thomas J. Smyth ◽  
Roger Marchant ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Genomic Islands ◽  
Clinical Strain ◽  
Whole Genome ◽  
Synonymous Mutations ◽  
Wide Range

AbstractPseudomonas aeruginosa uses quorum sensing (QS) to modulate the expression of several virulence factors that enable it to establish severe infections. The QS system in P. aeruginosa is complex, intricate and is dominated by two main N-acyl-homoserine lactone circuits, LasRI and RhlRI. These two QS systems work in a hierarchical fashion with LasRI at the top, directly regulating RhlRI. Together these QS circuits regulate several virulence associated genes, metabolites, and enzymes in P. aeruginosa. Paradoxically, LasR mutants are frequently isolated from chronic P. aeruginosa infections, typically among cystic fibrosis (CF) patients. This suggests P. aeruginosa can undergo significant evolutionary pathoadaptation to persist in long term chronic infections. In contrast, mutations in the RhlRI system are less common. Here, we have isolated a clinical strain of P. aeruginosa from a CF patient that has deleted the transcriptional regulator RhlR entirely. Whole genome sequencing shows the rhlR locus is deleted in PA80 alongside a few non-synonymous mutations in virulence factors including protease lasA and rhamnolipid rhlA, rhlB, rhlC. Importantly we did not observe any mutations in the LasRI QS system. PA80 does not appear to have an accumulation of mutations typically associated with several hallmark pathoadaptive genes (i.e., mexT, mucA, algR, rpoN, exsS, ampR). Whole genome comparisons show that P. aeruginosa strain PA80 is closely related to the hypervirulent Liverpool epidemic strain (LES) LESB58. PA80 also contains several genomic islands (GI’s) encoding virulence and/or resistance determinants homologous to LESB58. To further understand the effect of these mutations in PA80 QS regulatory and virulence associated genes, we compared transcriptional expression of genes and phenotypic effects with isogenic mutants in the genetic reference strain PAO1. In PAO1, we show that deletion of rhlR has a much more significant impact on the expression of a wide range of virulence associated factors rather than deletion of lasR. In PA80, no QS regulatory genes were expressed, which we attribute to the inactivation of the RhlRI QS system by deletion of rhlR and mutation of rhlI. This study demonstrates that inactivation of the LasRI system does not impact RhlRI regulated virulence factors. PA80 has bypassed the common pathoadaptive mutations observed in LasR by targeting the RhlRI system. This suggests that RhlRI is a significant target for the long-term persistence of P. aeruginosa in chronic CF patients. This raises important questions in targeting QS systems for therapeutic interventions.

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 Tackling Virulence of Pseudomonas aeruginosa by the Natural Furanone Sotolon

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 871
Author(s):  
Mohammed F. Aldawsari ◽  
El-Sayed Khafagy ◽  
Ahmed Al Saqr ◽  
Ahmed Alalaiwe ◽  
Hisham A. Abbas ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Therapeutic Agent ◽  
Bacterial Resistance ◽  
Inhibitory Concentration ◽  
Bacterial Biofilm ◽  
Resistant Bacteria ◽  
Resistance Development

The bacterial resistance development due to the incessant administration of antibiotics has led to difficulty in their treatment. Natural adjuvant compounds can be co-administered to hinder the pathogenesis of resistant bacteria. Sotolon is the prevailing aromatic compound that gives fenugreek its typical smell. In the current work, the anti-virulence activities of sotolon on Pseudomonas aeruginosa have been evaluated. P. aeruginosa has been treated with sotolon at sub-minimum inhibitory concentration (MIC), and production of biofilm and other virulence factors were assessed. Moreover, the anti-quorum sensing (QS) activity of sotolon was in-silico evaluated by evaluating the affinity of sotolon to bind to QS receptors, and the expression of QS genes was measured in the presence of sotolon sub-MIC. Furthermore, the sotolon in-vivo capability to protect mice against P. aeruginosa was assessed. Significantly, sotolon decreased the production of bacterial biofilm and virulence factors, the expression of QS genes, and protected mice from P. aeruginosa. Conclusively, the plant natural substance sotolon attenuated the pathogenicity of P. aeruginosa, locating it as a plausible potential therapeutic agent for the treatment of its infections. Sotolon can be used in the treatment of bacterial infections as an alternative or adjuvant to antibiotics to combat their high resistance to antibiotics.

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