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https://www.readbyqxmd.com/read/28188589/synergistic-activity-of-sub-inhibitory-concentrations-of-curcumin-with-ceftazidime-and-ciprofloxacin-against-pseudomonas-aeruginosa-quorum-sensing-related-genes-and-virulence-traits
#1
Shekoufeh Roudashti, Habib Zeighami, Hesam Mirshahabi, Shahin Bahari, Ali Soltani, Fakhri Haghi
Quorum sensing (QS) system in Pseudomonas aeruginosa may be an important target for pharmacological intervention. The present study aimed to investigate the synergetic activity of sub-MIC concentrations of curcumin (C) with ceftazidime (CAZ) and ciprofloxacin (CIP) against P. aeroginusa QS system. We determined the MIC and synergistic activity of C, CAZ and CIP against P. aeroginusa PAO1 using broth microdilution and checkerboard titration methods. The activity of sub-MIC (1/4 and 1/16 MIC) concentrations of C on the QS signal molecules was assessed using a reporter strain assay...
March 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28140677/furvina-inhibits-the-3-oxo-c12-hsl-based-quorum-sensing-system-of-pseudomonas-aeruginosa-and-qs-dependent-phenotypes
#2
Anabela Borges, Pedro Sousa, Alexandra Gaspar, Santiago Vilar, Fernanda Borges, Manuel Simões
Disruption of cell-cell communication or quorum sensing (QS) is considered a stimulating approach for reducing bacterial pathogenicity and resistance. Although several QS inhibitors (QSIs) have been discovered so far their clinical use remains distant. This problem can be circumvented by searching for QSI among drugs already approved for the treatment of different diseases. In this context, antibiotics have earned special attention. Whereas at high concentrations antibiotics exert a killing effect, at lower concentrations they may act as signaling molecules and as such can modulate gene expression...
January 31, 2017: Biofouling
https://www.readbyqxmd.com/read/28127392/bacterial-competition-and-quorum-sensing-signalling-shape-the-eco-evolutionary-outcomes-of-model-in-vitro-phage-therapy
#3
Rachel Mumford, Ville-Petri Friman
The rapid rise of antibiotic resistance has renewed interest in phage therapy - the use of bacteria-specific viruses (phages) to treat bacterial infections. Even though phages are often pathogen-specific, little is known about the efficiency and eco-evolutionary outcomes of phage therapy in polymicrobial infections. We studied this experimentally by exposing both quorum-sensing (QS) signalling PAO1 and QS-deficient lasR Pseudomonas aeruginosa genotypes (differing in their ability to signal intraspecifically) to lytic PT7 phage in the presence and absence of two bacterial competitors: Staphylococcus aureus and Stenotrophomonas maltophilia-two bacteria commonly associated with P...
February 2017: Evolutionary Applications
https://www.readbyqxmd.com/read/28119451/flavonoids-suppress-pseudomonas-aeruginosa-virulence-through-allosteric-inhibition-of-quorum-sensing-receptors
#4
Jon E Paczkowski, Sampriti Mukherjee, Amelia R McCready, Jian-Ping Cong, Christopher J Aquino, Hahn Kim, Brad R Henke, Chari D Smith, Bonnie L Bassler
Quorum sensing is a process of cell-cell communication that bacteria use to regulate collective behaviors. Quorum sensing depends on the production, detection, and group-wide response to extracellular signal molecules called autoinducers. In many bacterial species, quorum sensing controls virulence factor production. Thus, disrupting quorum sensing is considered a promising strategy to combat bacterial pathogenicity. Several members of a family of naturally-produced plant metabolites called flavonoids inhibit Pseudomonas aeruginosa biofilm formation by an unknown mechanism...
January 24, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28096154/influence-of-rhlr-and-lasr-on-polymyxin-pharmacodynamics-in-pseudomonas-aeruginosa-implications-for-quorum-sensing-inhibition-with-azithromycin
#5
Zackery P Bulman, Neang S Ly, Justin R Lenhard, Patricia N Holden, Jürgen B Bulitta, Brian T Tsuji
Quorum sensing's impact on polymyxin and azithromycin pharmacodynamics was assessed in Pseudomonas aeruginosa PAO1 and an isogenic rhlR/lasR double knockout. For polymyxin B, greater killing against the rhlR/lasR knockout versus PAO1 was observed at 10(8) CFU/mL(polymyxin B EC50:5.61 versus 12.5mg/L, respectively; p<0.005). Polymyxin B combined with azithromycin (256mg/L) was synergistic against each strain, significantly reducing the respective polymyxin B EC50 compared to monotherapy (p<0.005), and is a promising strategy to combat P...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28075113/pseudomonas-aeruginosa-lasr%C3%A2-dna-binding-is-directly-inhibited-by-quorum-sensing-antagonists
#6
Emma G Suneby, Leslie R Herndon, Tanya L Schneider
Inhibition of quorum sensing in Pseudomonas aeruginosa is of interest as a possible antivirulence strategy for this pathogenic bacterium. The LasR regulator protein is important in coordinating gene expression in response to quorum sensing signaling molecules. One predominant strategy for LasR inhibition is the development of small-molecule antagonists that mimic the native autoinducer, though the mechanism by which they inactivate LasR is not known. This work reveals that multiple antagonists function by binding to and stabilizing LasR in a conformation that renders it unable to bind DNA...
January 11, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28065820/bioavailability-enhanced-resveramax%C3%A2-modulates-quorum-sensing-and-inhibits-biofilm-formation-in-pseudomonas-aeruginosa-pao1
#7
H S Vasavi, H V Sudeep, H B Lingaraju, K Shyam Prasad
Quorum sensing (QS), a cell-to-cell communication mechanism present in many bacterial species plays a key role in regulating the virulence factor and biofilm formation in many pathogens, which causes severe public health risk. Therefore, interfering with QS mechanism offers an attractive strategy to combat bacterial infections. In the present study, anti-QS activity of a novel resveratrol formulation, Resveramax™, was detected using Chromobacterium violaceum biosensor bioassay and the effect of Resveramax on QS-regulated phenotypes in Pseudomonas aeruginosa PAO1 was assessed by standard protocols...
January 5, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28064429/structural-insight-into-the-gene-expression-profiling-of-the-hcn-operon-in-pseudomonas-aeruginosa
#8
Nilkanta Chowdhury, Angshuman Bagchi
Pseudomonas aeruginosa is a common opportunistic human pathogen. It generally attacks immunosuppressed patients like AIDS, cancer, cystic fibrosis, etc. The virulence of P. aeruginosa is mediated by various virulence factors. One of such potential virulence factors is HCN synthesized by HCN synthase enzyme, which is encoded by the hcnABC operon. The expressions of the genes of this operon are regulated by three transcriptional regulators, viz., LasR, ANR, and RhlR. In our previous work, we analyzed the molecular details of the functionalities of LasR...
January 7, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28049617/synthesis-of-antimicrobial-glucosamides-as-bacterial-quorum-sensing-mechanism-inhibitors
#9
Nripendra N Biswas, Tsz Tin Yu, Önder Kimyon, Shashidhar Nizalapur, Christopher R Gardner, Mike Manefield, Renate Griffith, David StC Black, Naresh Kumar
Bacteria communicate with one another and regulate their pathogenicity through a phenomenon known as quorum sensing (QS). When the bacterial colony reaches a threshold density, the QS system induces the production of virulence factors and the formation of biofilms, a powerful defence system against the host's immune responses. The glucosamine monomer has been shown to disrupt the bacterial QS system by inhibiting autoinducer (AI) signalling molecules such as the acyl-homoserine lactones (AHLs). In this study, the synthesis of acetoxy-glucosamides 8, hydroxy-glucosamides 9 and 3-oxo-glucosamides 12 was performed via the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N,N'-dicyclohexylcarbodiimide (DCC) coupling methods...
December 21, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28010047/distal-and-proximal-promoters-co-regulate-pqsr-expression-in-pseudomonas-aeruginosa
#10
John M Farrow, Everett C Pesci
The ubiquitous bacterium Pseudomonas aeruginosa is an opportunistic pathogen that can cause serious infections in immunocompromised individuals. P. aeruginosa virulence is controlled partly by intercellular communication, and the transcription factor PqsR is a necessary component in the P. aeruginosa cell-to-cell signaling network. PqsR acts as the receptor for the Pseudomonas quinolone signal, and it controls the production of 2-alkyl-4-quinolone molecules which are important for pathogenicity. Previous studies showed that the expression of pqsR is positively controlled by the quorum-sensing regulator LasR, but it was unclear how LasR is able to induce pqsR transcription...
December 23, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/28000767/a-diketopiperazine-factor-from-rheinheimera-aquimaris-qsi02-exhibits-anti-quorum-sensing-activity
#11
Shiwei Sun, Xiaoyun Dai, Jiao Sun, Xiangguo Bu, Caihong Weng, Hui Li, Hu Zhu
An ethyl acetate (EtOAc) extract isolated from the marine bacterium, Rheinheimera aquimaris QSI02, was found to exhibit anti-quorum sensing (anti-QS) activity. A subsequent bioassay-guided isolation protocol led to the detection of an active diketopiperazine factor, cyclo(Trp-Ser). Biosensor assay data showed that the minimum inhibitory concentration (MIC) of cyclo(Trp-Ser) ranged from 3.2 mg/ml to 6.4 mg/m for several microorganisms, including Escherichia coli, Chromobacterium violaceum CV026, Pseudomonas aeruginosa PA01, Staphylococcus aureus, and Candida albicans...
December 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924027/crystal-structure-of-pseudomonas-aeruginosa-rsal-bound-to-promoter-dna-reaffirms-its-role-as-a-global-regulator-involved-in-quorum-sensing
#12
Huaping Kang, Jianhua Gan, Jingru Zhao, Weina Kong, Jing Zhang, Miao Zhu, Fan Li, Yaqin Song, Jin Qin, Haihua Liang
Pseudomonas aeruginosa possesses at least three well-defined quorum-sensing (QS) (las, rhl and pqs) systems that control a variety of important functions including virulence. RsaL is a QS repressor that reduces QS signal production and ensures homeostasis by functioning in opposition to LasR. However, its regulatory role in signal homeostasis remains elusive. Here, we conducted a ChIP-seq assay and revealed that RsaL bound to two new targets, the intergenic regions of PA2228/PA2229 and pqsH/cdpR, which are required for PQS synthesis...
January 25, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/27902425/virulence-adaptations-of-pseudomonas-aeruginosa-isolated-from-patients-with-non-cystic-fibrosis-bronchiectasis
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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...
January 1, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/27781241/-laparoscopic-total-mesorectum-excision-with-the-guidance-of-membrane-anatomy
#19
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
#20
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
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