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https://www.readbyqxmd.com/read/27902425/virulence-adaptations-of-pseudomonas-aeruginosa-isolated-from-patients-with-non-cystic-fibrosis-bronchiectasis
#1
Taylor Evart Woo, Jessica Duong, Nicole M Jervis, Harvey R Rabin, Michael D Parkins, Douglas Gordon Storey
Pseudomonas aeruginosa is a major pathogen in chronic lung diseases such as cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis (nCFB). Much of our understanding regarding infections in nCFB patients is extrapolated from findings in CF with little direct investigation on the adaptation of P. aeruginosa in nCFB patients. As such, we investigated whether the adaptation of P. aeruginosa was indeed similar between nCFB and CF. From our prospectively collected biobank we identified 40 nCFB patients who had repeated P...
November 8, 2016: Microbiology
https://www.readbyqxmd.com/read/27900439/non-ribosomal-peptide-synthases-from-pseudomonas-aeruginosa-play-a-role-in-cyclodipeptide-biosynthesis-quorum-sensing-regulation-and-root-development-in-a-plant-host
#2
Omar González, Randy Ortíz-Castro, César Díaz-Pérez, Alma L Díaz-Pérez, Viridiana Magaña-Dueñas, José López-Bucio, Jesús Campos-García
Diverse molecules mediate cross-kingdom communication between bacteria and their eukaryotic partners and determine pathogenic or symbiotic relationships. N-acyl-L-homoserine lactone-dependent quorum-sensing signaling represses the biosynthesis of bacterial cyclodipeptides (CDPs) that act as auxin signal mimics in the host plant Arabidopsis thaliana. In this work, we performed bioinformatics, biochemical, and plant growth analyses to identify non-ribosomal peptide synthase (NRPS) proteins of Pseudomonas aeruginosa, which are involved in CDP synthesis...
November 30, 2016: Microbial Ecology
https://www.readbyqxmd.com/read/27857054/type-i-crispr-cas-targets-endogenous-genes-and-regulates-virulence-to-evade-mammalian-host-immunity
#3
Rongpeng Li, Lizhu Fang, Shirui Tan, Min Yu, Xuefeng Li, Sisi He, Yuquan Wei, Guoping Li, Jianxin Jiang, Min Wu
Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems in bacteria and archaea provide adaptive immunity against invading foreign nucleic acids. Previous studies suggest that certain bacteria employ their Type II CRISPR-Cas systems to target their own genes, thus evading host immunity. However, whether other CRISPR-Cas systems have similar functions during bacterial invasion of host cells remains unknown. Here we identify a novel role for Type I CRISPR-Cas systems in evading host defenses in Pseudomonas aeruginosa strain UCBPP-PA14...
December 2016: Cell Research
https://www.readbyqxmd.com/read/27836448/multilocus-amplicon-sequencing-of-pseudomonas-aeruginosa-cystic-fibrosis-airways-isolates-collected-prior-to-and-after-early-antipseudomonal-chemotherapy
#4
Sebastian Fischer, Leonie Greipel, Jens Klockgether, Marie Dorda, Lutz Wiehlmann, Nina Cramer, Burkhard Tümmler
BACKGROUND: Early antimicrobial chemotherapy can prevent or at least delay chronic cystic fibrosis (CF) airways infections with Pseudomonas aeruginosa. METHODS: During a 10-year study period P. aeruginosa was detected for the first time in 54 CF patients regularly seen at the CF centre Hannover. Amplicon sequencing of 34 loci of the P. aeruginosa core genome was performed in baseline and post-treatment isolates of the 15 CF patients who had remained P. aeruginosa - positive after the first round of antipseudomonal chemotherapy...
November 8, 2016: Journal of Cystic Fibrosis: Official Journal of the European Cystic Fibrosis Society
https://www.readbyqxmd.com/read/27834332/attenuation-of-quorum-sensing-regulated-behaviour-by-tinospora-cordifolia-extract-identification-of-its-active-constituents
#5
Viraj C Gala, Nithya R John, Ashok M Bhagwat, Ajit G Datar, Prashant S Kharkar, Krutika B Desai
BACKGROUND & OBJECTIVES: The pathogenicity of the nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii is regulated by their quorum sensing (QS) systems. The objective of the present study was to examine the effect of the cold ethyl acetate extract of Tinospora cordifolia stem on virulence and biofilm development in the wild type and clinical strains of P. aeruginosa and A. baumannii. The study was further aimed to identify the probable active constituents in the plant extract...
July 2016: Indian Journal of Medical Research
https://www.readbyqxmd.com/read/27825554/development-of-a-novel-series-of-non-natural-triaryl-agonists-and-antagonists-of-the-pseudomonas-aeruginosa-lasr-quorum-sensing-receptor
#6
Joseph N Capilato, Shane V Philippi, Thomas Reardon, Ashleigh McConnell, Dylan C Oliver, Amy Warren, Jill S Adams, Chun Wu, Lark J Perez
Bacterial chemical communication, through a process called quorum sensing (QS), plays a central role in infection in numerous bacterial pathogens. Quorum sensing in Pseudomonas aeruginosa employs a series of small molecule receptors including the master QS regulator, LasR. In this study we investigate a non-natural triaryl series of LasR ligands using a combination of structure activity relationship studies and computational modeling. These studies have enabled the identification of key structural requirements for ligand binding and have revealed a new strategy for inducing the therapeutically relevant antagonism of LasR...
October 20, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/27781241/-laparoscopic-total-mesorectum-excision-with-the-guidance-of-membrane-anatomy
#7
Pan Chi
The efficacy of laparoscopic total mesorectum excision (TME) has been confirmed by many clinical trials and guidelines. But two issues on laparoscopic TME are still questioned, including the integrity of specimen membrane of TME and the incidence of postoperative sexual dysfunction. According to my experiences and the primary results of the multicenter clinical trial (LASRE, clinicaltrials.gov identifier: NCT01899547) conducted by me, the integrity of the specimen membrane of laparoscopic TME is not inferior to the open TME...
October 25, 2016: Zhonghua Wei Chang Wai Ke za Zhi, Chinese Journal of Gastrointestinal Surgery
https://www.readbyqxmd.com/read/27756565/purification-and-characterization-of-pseudomonas-aeruginosa-lasr-expressed-in-acyl-homoserine-lactone-free-escherichia-coli-cultures
#8
Andrés Corral Lugo, Abdelali Daddaoua, Alvaro Ortega, Bertrand Morel, Ana Isabel Díez Peña, Manuel Espinosa-Urgel, Tino Krell
Quorum sensing systems are essential for bacterial communication. We report here the purification and characterization of the Pseudomonas aeruginosa LasR quorum sensing regulator purified from lysates of E. coli cultures grown in the absence of added acyl-homoserine lactones (AHL). We show by isothermal titration calorimetry that LasR recognizes different AHLs with an affinity of approximately 1 μM. The affinity of LasR for its cognate 3-Oxo-C12-AHL was similar to that of other AHLs, indicating that this regulator has not evolved to preferentially recognize its cognate AHL...
October 15, 2016: Protein Expression and Purification
https://www.readbyqxmd.com/read/27713502/nutrient-reduction-induced-stringent-responses-promote-bacterial-quorum-sensing-divergence-for-population-fitness
#9
Kelei Zhao, Xikun Zhou, Wujiao Li, Xiuyue Zhang, Bisong Yue
Bacteria use a cell-cell communication system termed quorum-sensing (QS) to adjust population size by coordinating the costly but beneficial cooperative behaviors. It has long been suggested that bacterial social conflict for expensive extracellular products may drive QS divergence and cause the "tragedy of the commons". However, the underlying molecular mechanism of social divergence and its evolutionary consequences for the bacterial ecology still remain largely unknown. By using the model bacterium Pseudomonas aeruginosa PAO1, here we show that nutrient reduction can promote QS divergence for population fitness during evolution but requiring adequate cell density...
October 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27703072/lasr-variant-cystic-fibrosis-isolates-reveal-an-adaptable-quorum-sensing-hierarchy-in-pseudomonas-aeruginosa
#10
John B Feltner, Daniel J Wolter, Christopher E Pope, Marie-Christine Groleau, Nicole E Smalley, E Peter Greenberg, Nicole Mayer-Hamblett, Jane Burns, Eric Déziel, Lucas R Hoffman, Ajai A Dandekar
: Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P...
October 4, 2016: MBio
https://www.readbyqxmd.com/read/27678057/evidence-for-direct-control-of-virulence-and-defense-gene-circuits-by-the-pseudomonas-aeruginosa-quorum-sensing-regulator-mvfr
#11
Damien Maura, Ronen Hazan, Tomoe Kitao, Alicia E Ballok, Laurence G Rahme
Pseudomonas aeruginosa defies eradication by antibiotics and is responsible for acute and chronic human infections due to a wide variety of virulence factors. Currently, it is believed that MvfR (PqsR) controls the expression of many of these factors indirectly via the pqs and phnAB operons. Here we provide strong evidence that MvfR may also bind and directly regulate the expression of additional 35 loci across the P. aeruginosa genome, including major regulators and virulence factors, such as the quorum sensing (QS) regulators lasR and rhlR, and genes involved in protein secretion, translation, and response to oxidative stress...
September 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27650847/transcription-associated-mutation-of-lasr-in-pseudomonas-aeruginosa
#12
Chao Wang, John R McPherson, Lian-Hui Zhang, Steve Rozen, Kanaga Sabapathy
Pseudomonas aeruginosa is an opportunistic pathogen which infects cystic fibrosis and cancer patients with compromised immune systems. LasR is a master regulator which controls the virulence of P. aeruginosa in response to bacterial cell-density and host signals. During infection, lasR is frequently mutated, conferring P. aeruginosa a growth advantage in hosts and enhances resistance to widely used antibiotics. However, the mechanistic basis of lasR mutation is not well understood. We have tested here the hypothesis that transcription strength is a contributory determinant of lasR mutagenesis...
October 2016: DNA Repair
https://www.readbyqxmd.com/read/27631025/environmentally-endemic-pseudomonas-aeruginosa-strains-with-mutations-in-lasr-are-associated-with-increased-disease-severity-in-corneal-ulcers
#13
John H Hammond, Wesley P Hebert, Amanda Naimie, Kathryn Ray, Rachel D Van Gelder, Antonio DiGiandomenico, Prajna Lalitha, Muthiah Srinivasan, Nisha R Acharya, Thomas Lietman, Deborah A Hogan, Michael E Zegans
The Steroids for Corneal Ulcers Trial (SCUT) was a multicenter, international study of bacterial keratitis in which 101 Pseudomonas aeruginosa infections were treated. Twenty-two of 101 P. aeruginosa isolates collected had a colony morphology characteristic of a loss-of-function mutation in lasR, the gene encoding a quorum-sensing master regulator. Ulcers caused by these 22 strains were associated with larger areas of corneal opacification, worse vision, and a lower rate of vision recovery in response to treatment than ulcers caused by the other isolates...
September 2016: MSphere
https://www.readbyqxmd.com/read/27602027/n-acetylglucosamine-inhibits-luxr-lasr-and-cvir-based-quorum-sensing-regulated-gene-expression-levels
#14
Önder Kimyon, Zehra I Ulutürk, Shashidhar Nizalapur, Matthew Lee, Samuel K Kutty, Sabrina Beckmann, Naresh Kumar, Mike Manefield
N-acetyl glucosamine, the monomer of chitin, is an abundant source of carbon and nitrogen in nature as it is the main component and breakdown product of many structural polymers. Some bacteria use N-acyl-L-homoserine lactone (AHL) mediated quorum sensing (QS) to regulate chitinase production in order to catalyze the cleavage of chitin polymers into water soluble N-acetyl-D-glucosamine (NAG) monomers. In this study, the impact of NAG on QS activities of LuxR, LasR, and CviR regulated gene expression was investigated by examining the effect of NAG on QS regulated green fluorescent protein (GFP), violacein and extracellular chitinase expression...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27503003/cranberry-derived-proanthocyanidins-impair-virulence-and-inhibit-quorum-sensing-of-pseudomonas-aeruginosa
#15
Vimal B Maisuria, Yossef Lopez-de Los Santos, Nathalie Tufenkji, Eric Déziel
Bacteria have evolved multiple strategies for causing infections that include producing virulence factors, undertaking motility, developing biofilms, and invading host cells. N-acylhomoserine lactone (AHL)-mediated quorum sensing (QS) tightly regulates the expression of multiple virulence factors in the opportunistic pathogenic bacterium Pseudomonas aeruginosa. Thus, inhibiting QS could lead to health benefits. In this study, we demonstrate an anti-virulence activity of a cranberry extract rich in proanthocyanidins (cerPAC) against P...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27498852/control-of-quorum-sensing-and-virulence-factors-of-pseudomonas-aeruginosa-using-phenylalanine-arginyl-%C3%AE-naphthylamide
#16
Soha El-Shaer, Mona Shaaban, Rasha Barwa, Ramadan Hassan
The spread of multidrug-resistant Pseudomonas aeruginosa isolates constitutes a serious clinical challenge. Bacterial efflux machinery is a crucial mechanism of resistance among P. aeruginosa. Efflux inhibitors such as phenylalanine arginyl β-naphthylamide (PAβN) promote the bacterial susceptibility to antimicrobial agents. The pathogenesis of P. aeruginosa is coordinated via quorum sensing (QS). This study aims to find out the impact of efflux pump inhibitor, PAβN, on QS and virulence attributes in clinical isolates of P...
October 2016: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/27464029/macrolide-treatment-inhibits-pseudomonas-aeruginosa-quorum-sensing-in-non-cystic-fibrosis-bronchiectasis-an-analysis-from-the-bronchiectasis-and-low-dose-erythromycin-study-trial
#17
Lucy D Burr, Geraint B Rogers, Alice C-H Chen, Brett R Hamilton, Gertruida F Pool, Steven L Taylor, Deon Venter, Simon D Bowler, Sally Biga, Michael A McGuckin
RATIONALE: The mechanism by which low-dose macrolide therapy reduces exacerbations in non-cystic fibrosis bronchiectasis is not known. Pseudomonas aeruginosa quorum sensing controls the expression of a range of pathogenicity traits and is inhibited by macrolide in vitro. Quorum sensing inhibition renders P. aeruginosa less pathogenic, potentially reducing its contribution to airway damage. OBJECTIVES: The aim of this study was to determine whether long-term low-dose erythromycin inhibits P...
October 2016: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/27456813/quorum-sensing-systems-differentially-regulate-the-production-of-phenazine-1-carboxylic-acid-in-the-rhizobacterium-pseudomonas-aeruginosa-pa1201
#18
Shuang Sun, Lian Zhou, Kaiming Jin, Haixia Jiang, Ya-Wen He
Pseudomonas aeruginosa strain PA1201 is a newly identified rhizobacterium that produces high levels of the secondary metabolite phenazine-1-carboxylic acid (PCA), the newly registered biopesticide Shenqinmycin. PCA production in liquid batch cultures utilizing a specialized PCA-promoting medium (PPM) typically occurs after the period of most rapid growth, and production is regulated in a quorum sensing (QS)-dependent manner. PA1201 contains two PCA biosynthetic gene clusters phz1 and phz2; both clusters contribute to PCA production, with phz2 making a greater contribution...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27242690/quorum-sensing-inhibiting-activity-of-streptomyces-coelicoflavus-isolated-from-soil
#19
Ramadan Hassan, Mona I Shaaban, Fatma M Abdel Bar, Areej M El-Mahdy, Shadi Shokralla
Quorum sensing (QS) systems communicate bacterial population and stimulate microbial pathogenesis through signaling molecules. Inhibition of QS signals potentially suppresses microbial infections. Antimicrobial properties of Streptomyces have been extensively studied, however, less is known about quorum sensing inhibitory (QSI) activities of Streptomyces. This study explored the QSI potential of Streptomyces isolated from soil. Sixty-five bacterial isolates were purified from soil samples with morphological characteristics of Streptomyces...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27209601/effect-of-silver-nanoparticles-against-the-formation-of-biofilm-by-pseudomonas-aeruginosa-an-in-silico-approach
#20
Satyanarayana Swamy Vyshnava, Dileep Kumar Kanderi, Shiva Prasad Panjala, Kamesh Pandian, Rajasekhar Reddy Bontha, Praveen Kumar Reddy Goukanapalle, Babajan Banaganapalli
Studies were undertaken to examine the mechanism of mediation of silver nanoparticles in inhibiting biofilm formation by Pseudomonas aeruginosa through LuxI/LuxR system of signal transduction. This study includes the basic signaling transduction mechanism LasR, QscR, RhlR, and Vfr signaling model systems. The arbitrary homology models built with the I-TASSER server were evaluated and validated with the Qmean web server. Based on the Z-score and the relative square mean distance (RMSD) values, the structures were validated...
May 21, 2016: Applied Biochemistry and Biotechnology
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