Rhamnolipids stabilize quorum sensing mediated cooperation in Pseudomonas aeruginosa

2020 ◽  
Vol 367 (10) ◽  
Author(s):  
Rodolfo García-Contreras ◽  
Daniel Loarca ◽  
Caleb Pérez-González ◽  
J Guillermo Jiménez-Cortés ◽  
Abigail Gonzalez-Valdez ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Carbon Source ◽  
Public Goods ◽  
Sole Carbon Source ◽  
Regulatory Genes ◽  
Chronic Infections ◽  
Toxic Metabolites ◽  
Serial Cultivation ◽  
Selection Of

ABSTRACT Pseudomonas aeruginosa is one of the main models to study social behaviors in bacteria since it synthesizes several exoproducts, including exoproteases and siderophores and release them to the environment. Exoproteases and siderophores are public goods that can be utilized by the individuals that produce them but also by non-producers, that are considered social cheaters. Molecularly exoprotease cheaters are mutants in regulatory genes such as lasR, and are commonly isolated from chronic infections and selected in the laboratory upon serial cultivation in media with protein as a sole carbon source. Despite that the production of exoproteases is exploitable, cooperators have also ways to restrict the growth and selection of social cheaters, for instance by producing toxic metabolites like pyocyanin. In this work, using bacterial competitions, serial cultivation and growth assays, we demonstrated that rhamnolipids which production is regulated by quorum sensing, selectively affect the growth of lasR mutants and are able to restrict social cheating, hence contributing to the maintenance of cooperation in Pseudomonas aeruginosa populations.

scholarly journals Pseudomonas aeruginosa las and rhl quorum-sensing systems are important for infection and inflammation in a rat prostatitis model

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2612-2619 ◽  
Author(s):  
Lisa K. Nelson ◽  
Genevieve H. D'Amours ◽  
Kimberley M. Sproule-Willoughby ◽  
Douglas W. Morck ◽  
Howard Ceri
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Tissue Damage ◽  
Inflammatory Markers ◽  
Bacterial Colonization ◽  
Opportunistic Pathogen ◽  
Infection Model ◽  
Chronic Infections ◽  
Strain Pao1 ◽  
Rat Prostate

Pseudomonas aeruginosa frequently acts as an opportunistic pathogen of mucosal surfaces; yet, despite causing aggressive prostatitis in some men, its role as a pathogen in the prostate has not been investigated. Consequently, we developed a Ps. aeruginosa infection model in the rat prostate by instilling wild-type (WT) Ps. aeruginosa strain PAO1 into the rat prostate. It was found that Ps. aeruginosa produced acute and chronic infections in this mucosal tissue as determined by bacterial colonization, gross morphology, tissue damage and inflammatory markers. WT strain PAO1 and its isogenic mutant PAO-JP2, in which both the lasI and rhlI quorum-sensing signal systems have been silenced, were compared during both acute and chronic prostate infections. In acute infections, bacterial numbers and inflammatory markers were comparable between WT PA01 and PAO-JP2; however, considerably less tissue damage occurred in infections with PAO-JP2. Chronic infections with PAO-JP2 resulted in reduced bacterial colonization, tissue damage and inflammation as compared to WT PAO1 infections. Therefore, the quorum-sensing lasI and rhlI genes in Ps. aeruginosa affect acute prostate infections, but play a considerably more important role in maintaining chronic infections. We have thus developed a highly reproducible model for the study of Ps. aeruginosa virulence in the prostate.

scholarly journals Computer-Aided Identification of Recognized Drugs as Pseudomonas aeruginosa Quorum-Sensing Inhibitors

2009 ◽  
Vol 53 (6) ◽  
pp. 2432-2443 ◽  
Author(s):  
Liang Yang ◽  
Morten Theil Rybtke ◽  
Tim Holm Jakobsen ◽  
Morten Hentzer ◽  
Thomas Bjarnsholt ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virtual Screening ◽  
Quorum Sensing ◽  
Bacterial Infections ◽  
Treatment Strategies ◽  
Significant Inhibition ◽  
Dependent Manner ◽  
Chronic Infections ◽  
Quorum Sensing Inhibitors ◽  
Regulated Gene Expression

ABSTRACT Attenuation of Pseudomonas aeruginosa virulence by the use of small-molecule quorum-sensing inhibitors (referred to as the antipathogenic drug principle) is likely to play a role in future treatment strategies for chronic infections. In this study, structure-based virtual screening was used in a search for putative quorum-sensing inhibitors from a database comprising approved drugs and natural compounds. The database was built from compounds which showed structural similarities to previously reported quorum-sensing inhibitors, the ligand of the P. aeruginosa quorum-sensing receptor LasR, and a quorum-sensing receptor agonist. Six top-ranking compounds, all recognized drugs, were identified and tested for quorum-sensing-inhibitory activity. Three compounds, salicylic acid, nifuroxazide, and chlorzoxazone, showed significant inhibition of quorum-sensing-regulated gene expression and related phenotypes in a dose-dependent manner. These results suggest that the identified compounds have the potential to be used as antipathogenic drugs. Furthermore, the results indicate that structure-based virtual screening is an efficient tool in the search for novel compounds to combat bacterial infections.

Antigenic variation and increase in pathogenicity in Pseudomonas aeruginosa as a result of growth on glucose or N-hexadecane as sole carbon source

1978 ◽  
Vol 24 (6) ◽  
pp. 675-679 ◽  
Author(s):  
Robert S. Stinson ◽  
D. E. Talburt
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbon Source ◽  
Outer Membrane ◽  
Sole Carbon Source ◽  
Antigenic Variation ◽  
Protein Composition ◽  
Cell Types ◽  
Additional Protein

When Pseudomonas aeruginosa is grown on glucose as opposed to n-hexadecane as the sole carbon source, the antigenicity, virulence, and protein composition of the outer membrane are altered. The hydrocarbon-grown cells demonstrate a 3-log increase in virulence over the glucose-grown cells (in mice). There also appears to be an additional protein present in the outer membrane of the n-hexadecane-grown cells. This protein may contribute to the observed antigenic differences between the two cell types.

scholarly journals A synthetic medium for the selection of yeasts able to utilize fatty acids as the sole carbon source.

1996 ◽  
Vol 42 (1) ◽  
pp. 87-91 ◽  
Author(s):  
ESTEBAN C. DELL'ANGELICA ◽  
DANIEL MILIKOWSKI ◽  
DANIEL A. SAENZ ◽  
CARLOS A. STELLA ◽  
EUGENIA H. RAMOS ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Selection Of

scholarly journals The nutritional environment is sufficient to select coexisting biofilm and quorum-sensing mutants of Pseudomonas aeruginosa

2022 ◽  
Author(s):  
Michelle R. Scribner ◽  
Amelia C. Stephens ◽  
Justin L. Huong ◽  
Anthony R. Richardson ◽  
Vaughn S. Cooper
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Dependent Manner ◽  
Chronic Infections ◽  
Concentration Dependent Manner ◽  
Surface Attachment ◽  
Bacterial Populations ◽  
Simple Medium ◽  
Associated Conditions

The evolution of bacterial populations during infections can be influenced by various factors including available nutrients, the immune system, and competing microbes, rendering it difficult to identify the specific forces that select on evolved traits. The genomes of Pseudomonas aeruginosa isolated from the airway of patients with cystic fibrosis (CF), for example, have revealed commonly mutated genes, but which phenotypes led to their prevalence is often uncertain. Here, we focus on effects of nutritional components of the CF airway on genetic adaptations by P. aeruginosa grown in either well-mixed (planktonic) or biofilm-associated conditions. After only 80 generations of experimental evolution in a simple medium with glucose, lactate, and amino acids, all planktonic populations diversified into lineages with mutated genes common to CF infections: morA , encoding a regulator of biofilm formation, or lasR , encoding a quorum sensing regulator that modulates the expression of virulence factors. Although mutated quorum sensing is often thought to be selected in vivo due to altered virulence phenotypes or social cheating, isolates with lasR mutations demonstrated increased fitness when grown alone and outcompeted the ancestral PA14 strain. Nonsynonymous SNPs in morA increased fitness in a nutrient concentration-dependent manner during planktonic growth and surprisingly also increased biofilm production. Populations propagated in biofilm conditions also acquired mutations in loci associated with chronic infections, including lasR and cyclic-di-GMP regulators roeA and wspF . These findings demonstrate that nutrient conditions and biofilm selection are sufficient to select mutants with problematic clinical phenotypes including increased biofilm and altered quorum sensing. Importance Pseudomonas aeruginosa produces dangerous chronic infections that are known for their rapid diversification and recalcitrance to treatment. We performed evolution experiments to identify adaptations selected by two specific aspects of the CF respiratory environment: nutrient levels and surface attachment. Propagation of P. aeruginosa in nutrients present within the CF airway was sufficient to drive diversification into subpopulations with identical mutations in regulators of biofilm and quorum sensing to those arising during infection. Thus, the adaptation of opportunistic pathogens to nutrients found in the host may select mutants with phenotypes that complicate treatment and clearance of infection.

scholarly journals Attenuation of Quorum Sensing Controlled Virulence Factors and Biofilm Formation by Edible Fruit Extract of Coccinia indica against Pseudomonas aeruginosa

2021 ◽  
pp. 756-764
Author(s):  
R. Shruthi Devi ◽  
P. Sankar Ganesh ◽  
A. S. Smiline Girija ◽  
J. Vijayashree Priyadharshini
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Crystal Violet Staining ◽  
Chronic Infections ◽  
Fruit Extract ◽  
Fluorescent Microscope ◽  
Edible Fruit ◽  
Coccinia Indica ◽  
Opportunistic Human Pathogen

Background: Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen that mainly infects immunocompromised individuals and patients with urinary tract infection and chronic infections of the respiratory pathways, including cystic fibrosis. Many quorum sensing (QS) controlled components such as bio surfactants and swarming motilities play an important role in the establishment of biofilms. Targeting these factors through anti-QS strategies prevent biofilm formation and treating infections. Coccinia indica commonly called little gourd is used to treat diabetes, wound, burn infections and has antioxidant, antibacterial and antitussive properties. Methods: The methanolic fruit extract of C. indica was prepared and screened for anti-QS and anti-biofilm formation activity. Pyocyanin inhibition, rhamnolipid, crystal violet staining assay tests was performed and the extract was observed under fluorescent microscope. Results: The results obtained are as follows - the fruit extract inhibits the pyocyanin at 58.13% and 42.27% at 0.5 mg/ml and 1.0 mg/ml, biofilm at 69.86% and 49.06% at 0.5 mg/ml and 1.0 mg/ml, inhibits rhamnolipid assay and under fluorescent microscope it is seen scattered whereas control produce biofilm matrix like appearance. Conclusion: Since less study has been made on the quorum sensing and biofilm activity of C.indica our study aimed to fulfil it and it was found that it exhibits good biofilm formation and thus can be used for treating infections.

scholarly journals The Impact of Pyroglutamate:Sulfolobus acidocaldariusHas a Growth Advantage overSaccharolobus solfataricusin Glutamate-Containing Media

Archaea ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Anna M. Vetter ◽  
Julia Helmecke ◽  
Dietmar Schomburg ◽  
Meina Neumann-Schaal
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Sulfolobus Solfataricus ◽  
Cell Extract ◽  
Sulfolobus Acidocaldarius ◽  
Intracellular Accumulation ◽  
Efficient Utilization ◽  
Crude Cell Extract ◽  
Toxic Metabolites ◽  
The Impact

Microorganisms are well adapted to their habitat but are partially sensitive to toxic metabolites or abiotic compounds secreted by other organisms or chemically formed under the respective environmental conditions. Thermoacidophiles are challenged by pyroglutamate, a lactam that is spontaneously formed by cyclization of glutamate under aerobic thermoacidophilic conditions. It is known that growth of the thermoacidophilic crenarchaeonSaccharolobus solfataricus(formerlySulfolobus solfataricus) is completely inhibited by pyroglutamate. In the present study, we investigated the effect of pyroglutamate on the growth ofS. solfataricusand the closely related crenarchaeonSulfolobus acidocaldarius.In contrast toS. solfataricus,S. acidocaldariuswas successfully cultivated with pyroglutamate as a sole carbon source. Bioinformatical analyses showed that both members of theSulfolobaceaehave at least one candidate for a 5-oxoprolinase, which catalyses the ATP-dependent conversion of pyroglutamate to glutamate. InS. solfataricus, we observed the intracellular accumulation of pyroglutamate and crude cell extract assays showed a less effective degradation of pyroglutamate. Apparently,S. acidocaldariusseems to be less versatile regarding carbohydrates and prefers peptidolytic growth compared toS. solfataricus. Concludingly,S. acidocaldariusexhibits a more efficient utilization of pyroglutamate and is not inhibited by this compound, making it a better candidate for applications with glutamate-containing media at high temperatures.

scholarly journals Quorum Sensing Is Not Required for Twitching Motility in Pseudomonas aeruginosa

2002 ◽  
Vol 184 (13) ◽  
pp. 3598-3604 ◽  
Author(s):  
Scott A. Beatson ◽  
Cynthia B. Whitchurch ◽  
Annalese B. T. Semmler ◽  
John S. Mattick
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Regulatory System ◽  
Regulatory Genes ◽  
Broth Culture ◽  
Twitching Motility ◽  
High Frequencies ◽  
Regulatory Systems ◽  
Compensatory Mutations ◽  
Wild Type Parent

ABSTRACT It has been reported that mutations in the quorum-sensing genes lasI and rhlI in Pseudomonas aeruginosa result in, among many other things, loss of twitching motility (A. Glessner, R. S. Smith, B. H. Iglewski, and J. B. Robinson, J. Bacteriol. 181:1623-1629, 1999). We constructed knockouts of lasI and rhlI and the corresponding regulatory genes lasR and rhlR and found no effect on twitching motility. However, twitching-defective variants accumulated during culturing of lasI and rhlI mutants. Further analysis showed that the stable twitching-defective variants of lasI and rhlI mutants had arisen as a consequence of secondary mutations in vfr and algR, respectively, both of which encode key regulators affecting a variety of phenotypes, including twitching motility. In addition, when grown in shaking broth culture, lasI and rhlI mutants, but not the wild-type parent, also accumulated unstable variants that lacked both twitching motility and swimming motility and appeared to be identical in phenotype to the S1 and S2 variants that were recently reported to occur at high frequencies in P. aeruginosa strains grown as a biofilm or in static broth culture (E. Deziel, Y. Comeau, and R. Villemur, J. Bacteriol. 183:1195-1204, 2001). These results indicate that mutations in one regulatory system may create distortions that select during subsequent culturing for compensatory mutations in other regulatory genes within the cellular network. This problem may have compromised some past studies of regulatory hierarchies controlled by quorum sensing and of bacterial regulatory systems in general.

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