keyword
MENU ▼
Read by QxMD icon Read
search

lasR

keyword
https://www.readbyqxmd.com/read/28627870/encapsulation-of-autoinducer-sensing-reporter-bacteria-in-reinforced-alginate-based-microbeads
#1
Ping Li, Mareike Müller, Matthew Wook Chang, Martin Frettlöh, Holger Schönherr
Quorum sensing, in which bacteria communities use signaling molecules for inter- and intracellular communication, has been intensively studied in recent decades. In order to fabricate highly sensitive easy-to-handle point of care biosensors that detect quorum sensing molecules, we have developed, as is reported here, reporter bacteria entrapped alginate-methacrylate (alginate-MA) hydrogel beads. The alginate-MA beads, which were obtained by electrostatic extrusion, were reinforced by photo-crosslinking to increase stability and thereby to reduce bacteria leaching...
June 19, 2017: ACS Applied Materials & Interfaces
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/28591665/inhibition-of-pseudomonas-aeruginosa-quorum-sensing-by-subinhibitory-concentrations-of-curcumin-with-gentamicin-and-azithromycin
#3
Shahin Bahari, Habib Zeighami, Hesam Mirshahabi, Shekoufeh Roudashti, Fakhri Haghi
OBJECTIVES: Pseudomonas aeruginosa quorum sensing (QS) circuits regulate virulence factors and co-ordinate bacterial pathogenicity. This study aimed to investigate the inhibitory activity of subinhibitory concentrations of curcumin with azithromycin and gentamicin against P. aeruginosa QS-related genes and virulence factors. METHODS: The minimum inhibitory concentrations (MICs) and synergistic activity of curcumin with azithromycin and gentamicin against P. aeruginosa PAO1 were determined using broth microdilution and checkerboard titration methods, respectively...
June 4, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28527130/pulse-generation-in-the-quorum-machinery-of-pseudomonas-aeruginosa
#4
Cicik Alfiniyah, Martin A Bees, A Jamie Wood
Pseudomonas aeruginosa is a Gram-negative bacterium that is responsible for a wide range of infections in humans. Colonies employ quorum sensing (QS) to coordinate gene expression, including for virulence factors, swarming motility and complex social traits. The QS signalling system of P. aeruginosa is known to involve multiple control components, notably the las, rhl and pqs systems. In this paper, we examine the las system and, in particular, the repressive interaction of rsaL, an embedded small regulative protein, employing recent biochemical information to aid model construction...
May 19, 2017: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/28494227/spontaneous-quorum-sensing-mutation-modulates-electroactivity-of-pseudomonas-aeruginosa-pa14
#5
Carola Berger, Miriam A Rosenbaum
Pseudomonas aeruginosa is able to interact with the anode of a bioelectrochemical system through redox active phenazines. Earlier studies showed that this interaction is strain and carbon source dependent. With a spontaneously formed ΔlasR mutant of P. aeruginosa PA14 and the wildtype, we investigated the connection between the complex quorum sensing network and current production. Depending on the carbon source, phenazine production and subsequently current generation are effected differently in these two populations...
April 29, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/28486805/isolated-reporter-bacteria-in-supramolecular-hydrogel-microwell-arrays
#6
Ping Li, Xiaoqiu Dou, Chuanliang Feng, Mareike Müller, Matthew Wook Chang, Martin Frettlöh, Holger Schönherr
The combination of supramolecular hydrogels formed by low molecular weight gelator self-assembly via noncovalent interactions within a scaffold derived from polyethylene glycol (PEG) affords an interesting approach to immobilize fully functional, isolated reporter bacteria in novel microwell arrays. The PEG-based scaffold serves as a stabilizing element and provides physical support for the self-assembly of the C2-phenyl-derived gelator on the micrometer scale. Supramolecular hydrogel microwell arrays with various shapes and sizes were used to isolate single or small numbers of Escherichia coli TOP10 pTetR-LasR-pLuxR-GFP...
May 31, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28479904/glyceryl-trinitrate-is-a-novel-inhibitor-of-quorum-sensing-in-pseudomonas-aeruginosa
#7
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
#8
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/28454561/a-comprehensive-multi-omics-approach-uncovers-adaptations-for-growth-and-survival-of-pseudomonas-aeruginosa-on-n-alkanes
#9
Sarah L Grady, Stephanie A Malfatti, Thusitha S Gunasekera, Brian K Dalley, Matt G Lyman, Richard C Striebich, Michael B Mayhew, Carol L Zhou, Oscar N Ruiz, Larry C Dugan
BACKGROUND: Examination of complex biological systems has long been achieved through methodical investigation of the system's individual components. While informative, this strategy often leads to inappropriate conclusions about the system as a whole. With the advent of high-throughput "omic" technologies, however, researchers can now simultaneously analyze an entire system at the level of molecule (DNA, RNA, protein, metabolite) and process (transcription, translation, enzyme catalysis)...
April 28, 2017: BMC Genomics
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
#10
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/28386534/scaffold-of-selenium-nanovectors-and-honey-phytochemicals-for-inhibition-of-pseudomonas-aeruginosa-quorum-sensing-and-biofilm-formation
#11
Prateeksha, Braj R Singh, M Shoeb, S Sharma, A H Naqvi, Vijai K Gupta, Brahma N Singh
Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS), a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors) and polyphenols of honey (HP) for enhancement of anti-QS activity of HP against P...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28351711/structure-based-virtual-screening-for-identification-of-potential-quorum-sensing-inhibitors-against-lasr-master-regulator-in-pseudomonas-aeruginosa
#12
Manmohit Kalia, Pradeep Kumar Singh, Vivek Kumar Yadav, Birendra Singh Yadav, Deepmala Sharma, Sahid Suhail Narvi, Ashutosh Mani, Vishnu Agarwal
Inter and intracellular communication in bacteria, which is known as quorum sensing (QS), is mediated by small diffusible signaling molecules known as autoinducers. QS regulates various virulence factors responsible for pathogenesis. Increasing resistance of microorganisms against traditional antibiotics has turned the focus towards the QS as it exerts less selective pressure preventing development of resistance among microorganisms. LasR, a transcription factor that controls QS in Pseudomonas aeruginosa, is an attractive therapeutic target for inhibitors...
June 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28349938/sers-detection-of-the-biomarker-hydrogen-cyanide-from-pseudomonas-aeruginosa-cultures-isolated-from-cystic-fibrosis-patients
#13
Rikke Kragh Lauridsen, Lea M Sommer, Helle Krogh Johansen, Tomas Rindzevicius, Søren Molin, Lars Jelsbak, Søren Balling Engelsen, Anja Boisen
Pseudomonas aeruginosa is the primary cause of chronic airway infections in cystic fibrosis (CF) patients. Persistent infections are seen from the first P. aeruginosa culture in about 75% of young CF patients, and it is important to discover new ways to detect P. aeruginosa at an earlier stage. The P. aeruginosa biomarker hydrogen cyanide (HCN) contains a triple bond, which is utilized in this study because of the resulting characteristic C≡N peak at 2135 cm(-1) in a Raman spectrum. The Raman signal was enhanced by surface-enhanced Raman spectroscopy (SERS) on a Au-coated SERS substrate...
March 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28240425/assessment-of-left-atrial-mechanical-function-and-synchrony-in-paroxysmal-atrial-fibrillation-with-two-dimensional-speckle-tracking-echocardiography
#14
Zhijuan Shang, Dechun Su, Tao Cong, Yinghui Sun, Yan Liu, Na Chen, Jun Yang
BACKGROUND: The aim of this study was to investigate left atrial (LA) function and synchrony in paroxysmal atrial fibrillation (PAF) patients using two-dimensional speckle tracking echocardiography (STE). METHODS: Forty-five PAF patients and 30 healthy controls were enrolled. LA peak ventricular systolic longitudinal strain (LAS-S ) and strain rate (LASR-S ) and left atrial longitudinal strain (LAS-A ) and strain rate (LASR-A ) during late diastole were determined using STE, and the standard deviation of the time to peak (TPSD) of the regional strains was calculated to quantify LA dyssynchrony...
February 2017: Echocardiography
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
#15
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
#16
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
#17
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
#18
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...
March 10, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28096154/influence-of-rhlr-and-lasr-on-polymyxin-pharmacodynamics-in-pseudomonas-aeruginosa-and-implications-for-quorum-sensing-inhibition-with-azithromycin
#19
Zackery P Bulman, Neang S Ly, Justin R Lenhard, Patricia N Holden, Jürgen B Bulitta, Brian T Tsuji
The impact of quorum sensing 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 than against PAO1 was observed at 10(8) CFU/ml (polymyxin B half-maximal effective concentration [EC50], 5.61 versus 12.5 mg/liter, respectively; P < 0.005). Polymyxin B combined with azithromycin (256 mg/liter) was synergistic against each strain, significantly reducing the respective polymyxin B EC50 compared to those with monotherapy (P < 0...
April 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
#20
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
keyword
keyword
62949
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"