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https://www.readbyqxmd.com/read/28607159/mechanisms-of-pyocyanin-toxicity-and-genetic-determinants-of-resistance-in-staphylococcus-aureus
#1
Michael J Noto, William J Burns, William N Beavers, Eric P Skaar
Pseudomonas aeruginosa and Staphylococcus aureus are commonly isolated from polymicrobial infections, such as wound infections and chronic respiratory infections of persons with cystic fibrosis. Despite their co-isolation, P. aeruginosa produces substances toxic to S. aureus, including pyocyanin, a blue pigmented molecule that functions in P. aeruginosa virulence. Pyocyanin inhibits S. aureus respiration, forcing it to derive energy from fermentation and adopt a small colony variant (SCV) phenotype. The mechanisms by which S...
June 12, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28591849/pseudomonas-aeruginosa-quorum-sensing-response-in-the-absence-of-functional-lasr-and-lasi-proteins-the-case-of-strain-148-a-virulent-dolphin-isolate
#2
Estefanía Morales, Abigail González-Valdez, Luis Servín-González, Gloria Soberón-Chávez
Pseudomonas aeruginosa is an opportunistic pathogen that presents a complex regulatory network called 'quorum-sensing', which is responsible for the transcription of genes coding for several traits implicated in its pathogenicity. Strain 148 is a dolphin-isolate that has been shown to produce quorum-sensing regulated virulence-traits and to be virulent in a mouse model, despite the fact that it contains a 20 kbp deletion that eliminates from the chromosome the lasR gene and the lasI promoter. LasR is a key quorum-sensing transcriptional regulator that, when coupled with the autoinducer 3-oxo-dodecanoyl homoserine lactone (3O-C12-HSL) produced by LasI, activates transcription of genes coding for some virulence-associated traits such as elastase, lasI, rhlI and rhlR...
June 7, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28582765/new-applications-of-genetically-modified-pseudomonas-aeruginosa-for-toxicity-detection-in-water
#3
Dengbin Yu, Yang-Chun Yong, Changyu Liu, Youxing Fang, Lu Bai, Shaojun Dong
A novel mediator-free method based on genetically modified bacteria was developed for detecting water toxicity, where genetically modified Pseudomonas aeruginosa (GM P. aeruginosa) was selected as the biosensor strain and pyocyanin (PYO) produced by this strain was used as the indicator. The toxicity response of GM P. aeruginosa to 3, 5-dichlorophenol (3, 5-DCP) was measured electrochemically and spectroscopically, and the half maximal inhibitory concentration (IC50) of 3, 5-DCP was determined to be 15.1 mg/L...
May 29, 2017: Chemosphere
https://www.readbyqxmd.com/read/28570940/electrochemical-sensors-for-identifying-pyocyanin-production-in-clinical-pseudomonas-aeruginosa-isolates
#4
Hunter J Sismaet, Ameet J Pinto, Edgar D Goluch
In clinical practice, delays in obtaining culture results impact patient care and the ability to tailor antibiotic therapy. Despite the advancement of rapid molecular diagnostics, the use of plate cultures inoculated from swab samples continues to be the standard practice in clinical care. Because the inoculation culture process can take between 24 and 48h before a positive identification test can be run, there is an unmet need to develop rapid throughput methods for bacterial identification. Previous work has shown that pyocyanin can be used as a rapid, redox-active biomarker for identifying Pseudomonas aeruginosa in clinical infections...
May 24, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28561859/human-calprotectin-affects-the-redox-speciation-of-iron
#5
Toshiki G Nakashige, Elizabeth M Nolan
We report that the metal-sequestering human host-defense protein calprotectin (CP, S100A8/S100A9 oligomer) affects the redox speciation of iron (Fe) in bacterial growth media and buffered aqueous solution. Under aerobic conditions and in the absence of an exogenous reducing agent, CP-Ser (S100A8(C42S)/S100A9(C3S) oligomer) depletes Fe from three different bacterial growth media preparations over a 48 h timeframe (T = 30 °C). The presence of the reducing agent β-mercaptoethanol accelerates this process and allows CP-Ser to deplete Fe over a ≈1 h timeframe...
May 31, 2017: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/28558232/transparent-carbon-ultramicroelectrode-arrays-for-the-electrochemical-detection-of-a-bacterial-warfare-toxin-pyocyanin
#6
Janine Elliott, Olja Simoska, Scott Karasik, Jason B Shear, Keith J Stevenson
Pyocyanin is a virulence factor produced as a secondary metabolite by the opportunistic human pathogen, Pseudomonas aeruginosa. Fast and direct detection of pyocyanin is of importance as it could provide important insights regarding P. aeruginosa's virulence mechanisms. Here, we present an electrochemical sensing platform of redox-active pyocyanin using transparent carbon ultramicroelectrode arrays (T-CUAs), which were made using a previously reported simple fabrication process ( Duay et al. Anal. Chem. 2015 , 87 , 10109 )...
June 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28539728/anti-quorum-sensing-activity-of-forsythia-suspense-on-chromobacterium-violaceum-and-pseudomonas-aeruginosa
#7
An Zhang, Wei-Hua Chu
BACKGROUND: Quorum sensing (QS) plays an important role in the production of virulence factors and pathogenicity in Pseudomonas aeruginosa, and the interruption of QS will be a hopeful pathway to combat bacterial infection. OBJECTIVE: In this study, we selected Forsythia suspense (Thunb.) Vahl from traditional Chinese herbal medicines for its anti-QS activity. MATERIALS AND METHODS: Anti-QS of F. suspense extracts (FSE) was monitored using the Chromobacterium violaceum 12472 bioassay...
April 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28513746/structure-functionality-relationship-and-pharmacological-profiles-of-pseudomonas-aeruginosa-alkylquinolone-quorum-sensing-modulators
#8
Ahmed A M Kamal, Lucia Petrera, Jens Eberhard, Rolf W Hartmann
An important paradigm in anti-infective research is the antivirulence concept. Pathoblockers are compounds which disarm bacteria of their arsenal of virulence factors. PqsR is a transcriptional regulator controlling the production of such factors in Pseudomonas aeruginosa, most prominently pyocyanin. In this work, a series of tool compounds based on the structure of the natural ligand 2-heptyl-4-quinolone (HHQ) were used for probing the structure-functionality relationship. Four different profiles are identified namely agonists, antagonists, inverse agonists and biphasic modulators...
May 31, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28484444/leaf-extracts-of-mangifera-indica-l-inhibit-quorum-sensing-regulated-production-of-virulence-factors-and-biofilm-in-test-bacteria
#9
Fohad M Husain, Iqbal Ahmad, Abdullah S Al-Thubiani, Hussein H Abulreesh, Ibrahim M AlHazza, Farrukh Aqil
Quorum sensing (QS) is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango) has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML) extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28479904/glyceryl-trinitrate-is-a-novel-inhibitor-of-quorum-sensing-in-pseudomonas-aeruginosa
#10
Hisham A Abbas, Moutaz A Shaldam
BACKGROUND: Targeting quorum sensing is an alternative approach to antibiotics.Targeting quorum sensing-regulated virulence will disarm the pathogen without exerting pressure on its growth. As a result, emergence of resistance is avoided and the immune system can easily eradicate bacteria. OBJECTIVES: Investigation of the possible inhibition of quorum sensing-regulated virulence of Pseudomonas aeruginosa by glyceryltrinitrate. METHODS: The quorum sensing inhibiting activity of glyceryl trinitrate was assessed by inhibition of violacein production in Chromobacterium violaceum ATCC 12472...
December 2016: African Health Sciences
https://www.readbyqxmd.com/read/28466892/the-multi-output-incoherent-feedforward-loop-constituted-by-the-transcriptional-regulators-lasr-and-rsal-confers-robustness-to-a-subset-of-quorum-sensing-genes-in-pseudomonas-aeruginosa
#11
Roslen Bondí, Francesca Longo, Marco Messina, Francesca D'Angelo, Paolo Visca, Livia Leoni, Giordano Rampioni
Quorum sensing (QS) is an intercellular communication system which controls virulence-related phenotypes in the human pathogen Pseudomonas aeruginosa. LasR is the QS receptor protein which responds to the signal molecule N-(3-oxododecanoyl)homoserine lactone (3OC12-HSL) and promotes signal production by increasing the transcription of the 3OC12-HSL synthase gene, lasI. LasR also activates the expression of other genes, including rsaL, coding for the RsaL protein which acts as a transcriptional repressor of lasI...
May 3, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28460167/imaging-bacterial-interspecies-chemical-interactions-by-surface-enhanced-raman-scattering
#12
Gustavo Bodelón, Verónica Montes-García, Celina Costas, Ignacio Pérez-Juste, Jorge Pérez-Juste, Isabel Pastoriza-Santos, Luis M Liz-Marzán
Microbes produce bioactive chemical compounds to influence the physiology and growth of their neighbors, and our understanding of their biological activities may be enhanced by our ability to visualize such molecules in vivo. We demonstrate here the application of surface-enhanced Raman scattering spectroscopy for simultaneous detection of quorum-sensing-regulated pyocyanin and violacein, produced respectively by Pseudomonas aeruginosa and Chromobacterium violaceum bacterial colonies, grown as a coculture on agar-based plasmonic substrates...
May 5, 2017: ACS Nano
https://www.readbyqxmd.com/read/28453568/baicalin-inhibits-biofilm-formation-attenuates-the-quorum-sensing-controlled-virulence-and-enhances-pseudomonas-aeruginosa-clearance-in-a-mouse-peritoneal-implant-infection-model
#13
Jing Luo, Biying Dong, Ke Wang, Shuangqi Cai, Tangjuan Liu, Xiaojing Cheng, Danqing Lei, Yanling Chen, Yanan Li, Jinliang Kong, Yiqiang Chen
The quorum sensing (QS) circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs) of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro...
2017: PloS One
https://www.readbyqxmd.com/read/28421612/prospective-bacterial-quorum-sensing-inhibitors-from-indian-medicinal-plant-extracts
#14
Bipransh Kumar Tiwary, Runu Ghosh, Saurav Moktan, Vivek Kumar Ranjan, Priyankar Dey, Dibakar Choudhury, Somit Dutta, Dipanwita Deb, Abhaya Prasad Das, Ranadhir Chakraborty
As virulence of many pathogenic bacteria is regulated by the phenomenon of quorum sensing (QS), the present study aimed to find the QS-inhibiting (QS-I) property (if any) in sixty-one Indian medicinal plants. The presence of QS-I compound in the leaf-extract was evaluated by its ability to inhibit production of pigment in Chromobacterium violaceum MTCC 2656 (violacein) and Pseudomonas aeruginosa MTCC 2297 (pyocyanin) or swarming of P. aeruginosa MTCC 2297. Extracts of three plants, Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis have shown a dose- dependent inhibition of violacein production with no negative effect on bacterial growth...
April 19, 2017: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28408162/nuclear-protein-hmgn2-attenuates-pyocyanin-induced-oxidative-stress-via-nrf2-signaling-and-inhibits-pseudomonas-aeruginosa-internalization-in-a549-cells
#15
Keyun Liu, Xinyuan Wang, Kaihui Sha, Fumei Zhang, Feng Xiong, Xiaoying Wang, Junli Chen, Jingyu Li, Leonid P Churilov, Shanze Chen, Yi Wang, Ning Huang
Pyocyanin (PCN, 1-hydroxy-5-methyl-phenazine) is one of the most essential virulence factors of Pseudomonas aeruginosa (PA) to cause various cytotoxic effects in long-term lung infectious diseases, however the early effect of this bacterial toxin during PA infection and subsequent autonomous immune response in host cells have not been fully understood yet. Our results display that early onset of PCN stimulates Pseudomonas aeruginosa PAO1 adhesion and invasion in A549 cells via ROS production. Non-histone nuclear protein HMGN2 is found to be involved in the regulation of PCN-induced oxidative stress by promoting intracellular ROS clearance...
April 10, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28396663/bacterial-secretant-from-pseudomonas-aeruginosa-dampens-inflammasome-activation-in-a-quorum-sensing-dependent-manner
#16
Jungmin Yang, Kang-Mu Lee, Sangjun Park, Yoeseph Cho, Eunju Lee, Jong-Hwan Park, Ok Sarah Shin, Junghyun Son, Sang Sun Yoon, Je-Wook Yu
Inflammasome signaling can contribute to host innate immune defense against bacterial pathogens such as Pseudomonas aeruginosa. However, bacterial evasion of host inflammasome activation is still poorly elucidated. Quorum sensing (QS) is a bacterial communication mechanism that promotes coordinated adaptation by triggering expression of a wide range of genes. QS is thought to strongly contribute to the virulence of P. aeruginosa, but the molecular impact of bacterial QS on host inflammasome defense is completely unknown...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28370665/induction-of-the-pho-regulon-and-polyphosphate-synthesis-against-spermine-stress-in-pseudomonas-aeruginosa
#17
Yu-Chih Peng, ChienYi Lu, Guoqing Li, Zehava Eichenbaum, Chung-Dar Lu
Growth of Pseudomonas aeruginosa on spermine requires a functional γ-glutamylpolyamine synthetase PauA2. Not only subjected to growth inhibition by spermine, the pauA2 mutant became more sensitive to β-lactam antibiotics in human serum. To explore PauA2 as a potential target of drug development, suppressors of the pauA2 mutant, which alleviated toxicity, were isolated from selection plates containing spermine. These suppressors share common phenotypic changes including delayed growth rate, retarded swarming motility, and pyocyanin overproduction...
June 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28364274/quorum-quenching-properties-of-actinobacteria-isolated-from-malaysian-tropical-soils
#18
Kavimalar Devaraj, Geok Yuan Annie Tan, Kok-Gan Chan
In this study, a total of 147 soil actinobacterial strains were screened for their ability to inhibit response of Chromobacterium violaceum CV026 to short chain N-acyl homoserine lactone (AHL) which is a quorum sensing molecule. Of these, three actinobacterial strains showed positive for violacein inhibition. We further tested these strains for the inhibition of Pseudomonas aeruginosa PAO1 quorum sensing-regulated phenotypes, namely, swarming and pyocyanin production. The three strains were found to inhibit at least one of the quorum sensing-regulated phenotypes of PAO1...
March 31, 2017: Archives of Microbiology
https://www.readbyqxmd.com/read/28350449/long-chain-4-aminoquinolines-as-quorum-sensing-inhibitors-in-serratia-marcescens-and-pseudomonas-aeruginosa
#19
Ivana Aleksić, Sandra Šegan, Filip Andrić, Mario Zlatović, Ivana Moric, Dejan M Opsenica, Lidija Senerovic
Antibiotic resistance has become a serious global threat to public health; therefore, improved strategies and structurally novel antimicrobials are urgently needed to combat infectious diseases. Here we report a new type of highly potent 4-aminoquinoline derivatives as quorum sensing inhibitors in Serratia marcescens and Pseudomonas aeruginosa, exhibiting weak bactericidal activities (minimum inhibitory concentration (MIC) > 400 μM). Through detailed structure-activity study, we have identified 7-Cl and 7-CF3 substituted N-dodecylamino-4-aminoquinolines (5 and 10) as biofilm formation inhibitors with 50% biofilm inhibition at 69 μM and 63 μM in S...
April 10, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28333255/alkaline-protease-contributes-to-pyocyanin-production-in-pseudomonas-aeruginosa
#20
Kazuhiro Iiyama, Eigo Takahashi, Jae Man Lee, Hiroaki Mon, Mai Morishita, Takahiro Kusakabe, Chisa Yasunaga-Aoki
The role of the alkaline protease (AprA) in pyocyanin production in Pseudomonas aeruginosa was investigated. AprA was overproduced when a plasmid carrying the aprA gene was introduced to an aprA-deletion mutant strain, EG03; thus, aprA-complemented EG03 was used as an overproducing strain. The complemented strain produced higher pyocyanin than the mutant strain in all commercially available media evaluated. Particularly, pyocyanin production was higher in the complemented than in the parental strain in brain-heart infusion and tryptic soy broths...
April 1, 2017: FEMS Microbiology Letters
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