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Quorum sensing

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https://www.readbyqxmd.com/read/28731474/bacterial-transcriptome-remodeling-during-sequential-co-culture-with-a-marine-dinoflagellate-and-diatom
#1
Marine Landa, Andrew S Burns, Selena J Roth, Mary Ann Moran
In their role as primary producers, marine phytoplankton modulate heterotrophic bacterial activities through differences in the types and amounts of organic matter they release. This study investigates the transcriptional response of bacterium Ruegeria pomeroyi, a member of the Roseobacter clade known to affiliate with diverse phytoplankton groups in the ocean, during a shift in phytoplankton taxonomy. The bacterium was initially introduced into a culture of the dinoflagellate Alexandrium tamarense, and then experienced a change in phytoplankton community composition as the diatom Thalassiosira pseudonana gradually outcompeted the dinoflagellate...
July 21, 2017: ISME Journal
https://www.readbyqxmd.com/read/28731269/biofilm-formation-and-antibiotic-resistance-in-klebsiella-pneumoniae-urinary-strains
#2
Claudia Vuotto, Francesca Longo, Chiara Pascolini, Gianfranco Donelli, Maria Pia Balice, Maria Francesca Libori, Valentina Tiracchia, Antonino Salvia, Pietro Emanuele Varaldo
AIMS: Multi-drug resistant Klebsiella pneumoniae has become a relevant healthcare-associated pathogen. Capsule, type 1 and 3 fimbriae (mrkA gene), type 2 quorum-sensing system (luxS), synthesis of D-galactan I (wbbM), LPS transport (wzm) and poly-beta-1,6-N-acetyl-D-glucosamine (pgaA) seem involved in K. pneumoniae biofilm. Non-enzymatic antibiotic resistance is related to non-expression or mutation of porins (OmpK35 and OmpK36), and efflux pump (acrB) over-expression. The aim of this study was to analyse some virulence factors of K...
July 21, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28729627/a-mechanism-based-qstr-model-for-acute-to-chronic-toxicity-extrapolation-a-case-study-of-antibiotics-on-luminous-bacteria
#3
Dali Wang, Yue Gu, Min Zheng, Wei Zhang, Zhifen Lin, Ying Liu
The determination of the chronic toxicity is time-consumed and costly, so it's of great interest to predict the chronic toxicity based on acute data. Current methods include the acute to chronic ratios (ACRs) and the QSTR models, both of which have some usage limitations. In this paper, the acute and chronic mixture toxicity of three types of antibiotics, namely sulfonamides, sulfonamide potentiators and tetracyclines, were determined by a bioluminescence inhibition test. A novel QSTR model was developed for predicting the chronic mixture toxicity using the acute data and docking-based descriptors...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28729265/the-complete-genome-sequence-of-trueperella-pyogenes-ufv1-reveals-a-processing-system-involved-in-the-quorum-sensing-signal-response
#4
Vinícius da Silva Duarte, Laura Treu, Stefano Campanaro, Roberto Sousa Dias, Cynthia Canedo da Silva, Alessio Giacomini, Viviana Corich, Sérgio Oliveira de Paula
We present here the complete genome sequence of Trueperella pyogenes UFV1. The 2.3-Mbp genome contains an extremely interesting AI-2 transporter and processing system related to the quorum-sensing signal response. This specific feature is described in this species for the first time and might be responsible for a new pathogenic behavior.
July 20, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28729210/deficiency-of-quorum-sensing-system-inhibits-the-resistance-selection-of-pseudomonas-aeruginosa-to-ciprofloxacin-and-levofloxacin-in-vitro
#5
Yating Gao, Jinju Duan, Xin Geng, Zhiqi Zhang, Ruiqin Zhang, Xiaoxia Li, Shuyun Wang, Jianbang Kang, Donghong Yin, Yan Song
OBJECTIVES: The objective was to investigate how deficient of quorum sensing system (QS) affects minimal inhibitory concentrations (MICs) of Pseudomonas aeruginosa strains to ciprofloxacin (CIP) and levofloxacin (LEV) in vitro. METHODS: Collected the clinical Pseudomonas aeruginosa isolates. Screened the strains deficient of QS genes by the PCR agarose electrophoresis, and then randomly picked out normal strains with the same number of deficient ones. All strains incubated on the different CIP-concentration Mueller-Hinton agars for five days, the different concentrations of CIP respectively refered to 0...
July 17, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28729051/inhibiting-effects-of-fructanase-on-competence-stimulating-peptide-dependent-quorum-sensing-system-in-streptococcus-mutans
#6
Yusuke Suzuki, Ryo Nagasawa, Hidenobu Senpuku
Streptococcus mutans produces glucosyltransferases encoded by the gtfB and gtfC genes, which synthesize insoluble glucan, and both insoluble and soluble glucans by conversion of sucrose, and are known as principal agents to provide strong biofilm formation and demineralization on tooth surfaces. S. mutans possess a Com-dependent quorum sensing (QS) system, which is important for survival in severe conditions. The QS system is stimulated by the interaction between ComD {Receptor to competence-stimulating peptide (CSP)} encoded by the comD and CSP encoded by the comC, and importantly associated with bacteriocin production and genetic competence...
July 17, 2017: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
https://www.readbyqxmd.com/read/28722830/ralfuranones-contribute-to-mushroom-type-biofilm-formation-by-ralstonia-solanacearum-strain-oe1-1
#7
Yuka Mori, Yuki Hosoi, Shiho Ishikawa, Kazusa Hayashi, Yu Asai, Hideyuki Ohnishi, Mika Shimatani, Kanako Inoue, Kenichi Ikeda, Hitoshi Nakayashiki, Yasuyo Nishimura, Kouhei Ohnishi, Akinori Kiba, Kenji Kai, Yasufumi Hikichi
After invasion into intercellular spaces of tomato plants, the soil-borne plant pathogenic Ralstonia solanacearum strain OE1-1 forms mushroom-shaped biofilms (mushroom-type biofilms, mBFs) on tomato cells, leading to its virulence. The strain OE1-1 produces aryl-furanone secondary metabolites, ralfuranones (A, B, J, K and L), dependent on the quorum sensing (QS) system with methyl 3-hydroxymyristate (3-OH MAME) synthesized by PhcB as a QS signal. Ralfuranones are associated with the feedback loop of the QS system...
July 19, 2017: Molecular Plant Pathology
https://www.readbyqxmd.com/read/28720734/lack-of-acrb-efflux-function-confers-loss-of-virulence-on-salmonella-enterica-serovar-typhimurium
#8
Xuan Wang-Kan, Jessica M A Blair, Barbara Chirullo, Jonathan Betts, Roberto M La Ragione, Alasdair Ivens, Vito Ricci, Timothy J Opperman, Laura J V Piddock
AcrAB-TolC is the paradigm resistance-nodulation-division (RND) multidrug resistance efflux system in Gram-negative bacteria, with AcrB being the pump protein in this complex. We constructed a nonfunctional AcrB mutant by replacing D408, a highly conserved residue essential for proton translocation. Western blotting confirmed that the AcrB D408A mutant had the same native level of expression of AcrB as the parental strain. The mutant had no growth deficiencies in rich or minimal medium. However, compared with wild-type SL1344, the mutant had increased accumulation of Hoechst 33342 dye and decreased efflux of ethidium bromide and was multidrug hypersusceptible...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28716362/phosphoenolpyruvate-phosphotransferase-system-components-positively-regulate-klebsiella-biofilm-formation
#9
Yu-Tze Horng, Chi-Jen Wang, Wen-Ting Chung, Huei-Jen Chao, Yih-Yuan Chen, Po-Chi Soo
BACKGROUND/PURPOSE: Klebsiella pneumoniae is one of the leading causes of device-related infections (DRIs), which are associated with attachment of bacteria to these devices to form a biofilm. The latter is composed of not only bacteria but also extracellular polymeric substances (EPSes) consisting of extracellular DNAs, polysaccharides, and other macromolecules. The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) regulates diverse processes of bacterial physiology...
June 29, 2017: Journal of Microbiology, Immunology, and Infection, Wei Mian Yu Gan Ran za Zhi
https://www.readbyqxmd.com/read/28716170/sinonasal-t2r-mediated-nitric-oxide-production-in-response-to-bacillus-cereus
#10
Ryan M Carey, Alan D Workman, Carol H Yan, Bei Chen, Nithin D Adappa, James N Palmer, David W Kennedy, Robert J Lee, Noam A Cohen
BACKGROUND: Upper airway epithelial cells produce bactericidal nitric oxide (NO) in response to both gram-positive and gram-negative bacteria. Our previous work demonstrated that T2R38, a bitter taste receptor (T2R) expressed in airway epithelium, produces NO in response to quorum-sensing molecules secreted by Pseudomonas aeruginosa. We also demonstrated that Staphylococci products elicit an NO response when using a T2R-independent pathway. When screening additional human pathogens for epithelial T2R activation, we found that the gram-positive aerobe Bacillus cereus secretes a T2R agonist that yields NO production...
July 1, 2017: American Journal of Rhinology & Allergy
https://www.readbyqxmd.com/read/28715477/the-rhlr-quorum-sensing-receptor-controls-pseudomonas-aeruginosa-pathogenesis-and-biofilm-development-independently-of-its-canonical-homoserine-lactone-autoinducer
#11
Sampriti Mukherjee, Dina Moustafa, Chari D Smith, Joanna B Goldberg, Bonnie L Bassler
Quorum sensing (QS) is a bacterial cell-to-cell communication process that relies on the production, release, and response to extracellular signaling molecules called autoinducers. QS controls virulence and biofilm formation in the human pathogen Pseudomonas aeruginosa. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, which produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Here, we use biofilm analyses, reporter assays, RNA-seq studies, and animal infection assays to show that RhlR directs both RhlI-dependent and RhlI-independent regulons...
July 17, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28714256/a1s_2811-a-chea-y-like-hybrid-two-component-regulator-from-acinetobacter%C3%A2-baumannii-atcc17978-is-involved-in-surface-motility-and-biofilm-formation-in-this-bacterium
#12
Rong Chen, Ruichen Lv, Lisheng Xiao, Min Wang, Zongmin Du, Yafang Tan, Yujun Cui, Yanfeng Yan, Yanping Luo, Ruifu Yang, Yajun Song
Two-component systems in Acinetobacter baumannii are associated with its virulence, drug resistance, motility, biofilm formation, and other characteristics. In this study, we used RecAb , a genetic engineering method, to investigate the function of A1S_2811 in A. baumannii strain ATCC17978. A1S_2811, a hypothetical hybrid sensor histidine kinase/response regulator, has four histidine-containing phosphotransfer domains, a CheA-like regulatory domain, and a CheY-like receiver domain at its C terminus. Compared with the ATCC17978 strain, both surface motility and biofilm formation at the gas-liquid interface decreased significantly in the A1S_2811 knock-out strain...
July 17, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28713342/nf-%C3%AE%C2%BAbp50-and-hdac1-interaction-is-implicated-in-the-host-tolerance-to-infection-mediated-by-the-bacterial-quorum-sensing-signal-2-aminoacetophenone
#13
Arunava Bandyopadhaya, Amy Tsurumi, Laurence G Rahme
Some bacterial quorum sensing (QS) small molecules are important mediators of inter-kingdom signaling and impact host immunity. The QS regulated small volatile molecule 2-aminoacetophenone (2-AA), which has been proposed as a biomarker of Pseudomonas aeruginosa colonization in chronically infected human tissues, is critically involved in "host tolerance training" that involves a distinct molecular mechanism of host chromatin regulation through histone deacetylase (HDAC)1. 2-AA's epigenetic reprogramming action enables host tolerance to high bacterial burden and permits long-term presence of P...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28712963/anti-quorum-sensing-activity-of-pistacia-atlantica-against-pseudomonas-aeruginosa-pao1-and-identification-of-its-bioactive-compounds
#14
H Kordbacheh, F Eftekhar, S N Ebrahimi
Pseudomonas aeruginosa is a multidrug resistant opportunistic pathogen and an important cause of nosocomial infections. Quorum-sensing (QS) is a process in which bacterial cell-cell communication can regulates production of many virulence factors including pigment formation and the ability to form biofilm which is essential for establishment of chronic infections. We examined the inhibitory effect of Pistacia atlantica (Anacardiaceae) methanolic leaf extract and its bioactive components on biofilm formation and pigment production by P...
July 14, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28709374/nanoparticles-as-efflux-pump-and-biofilm-inhibitor-to-rejuvenate-bactericidal-effect-of-conventional-antibiotics
#15
REVIEW
Divya Gupta, Ajeet Singh, Asad U Khan
The universal problem of bacterial resistance to antibiotic reflects a serious threat for physicians to control infections. Evolution in bacteria results in the development of various complex resistance mechanisms to neutralize the bactericidal effect of antibiotics, like drug amelioration, target modification, membrane permeability reduction, and drug extrusion through efflux pumps. Efflux pumps acquire a wide range of substrate specificity and also the tremendous efficacy for drug molecule extrusion outside bacterial cells...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28704947/sponge-inspired-dibromohemibastadin-prevents-and-disrupts-bacterial-biofilms-without-toxicity
#16
Tiffany Le Norcy, Hendrik Niemann, Peter Proksch, Karen Tait, Isabelle Linossier, Karine Réhel, Claire Hellio, Fabienne Faÿ
Since the banning of several families of compounds in antifouling (AF) coatings, the search for environmentally friendly AF compounds has intensified. Natural sources of AF compounds have been identified in marine organisms and can be used to create analogues in laboratory. In a previous study, we identified that dibromohemibastadin-1 (DBHB) is a promising AF molecule, leading to the inhibition of the activity of phenoloxidase, an enzyme involved in the attachment of mussels to surfaces. This paper describes the activity of the DBHB on biofilm formation and its detachment and on bacterial adhesion and communication: quorum sensing...
July 12, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28702016/burn-serum-increases-staphylococcus-aureus-biofilm-formation-via-oxidative-stress
#17
Supeng Yin, Bei Jiang, Guangtao Huang, Yali Gong, Bo You, Zichen Yang, Yu Chen, Jing Chen, Zhiqiang Yuan, Ming Li, Fuquan Hu, Yan Zhao, Yizhi Peng
Staphylococcus aureus is a common pathogen isolated from burn patients that can form biofilms on burn wounds and implanted deep vein catheters, which often leads to refractory infections or even biofilm-related sepsis. As biofilm formation is usually regulated by environmental conditions, we hypothesized that serum composition may be altered after burn injury, potentially affecting the ability of infecting bacteria to form biofilms. As predicted, we observed that serum from burn-injured rats increases biofilm formation by S...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28698104/pseudomonas-aeruginosa-quorum-sensing-modulates-immune-responses-an-updated-review-article
#18
REVIEW
Ashraf Kariminik, Majid Baseri-Salehi, Babak Kheirkhah
Pseudomonas aeruginosa is an opportunistic bacterium which induces some complications in immunocompromised patients. Pseudomonas aeruginosa is a quorum-sensing using bacterium which regulates its genes expression. The bacterium uses two famous pathways for quorum sensing entitled LasI/LasR and RhlI/RhlR systems. It has been documented that the bacteria which use quorum sensing are able to overcome immune responses. This review article aims to present recent information regarding the effects of Pseudomonas aeruginosa quorum sensing systems on the host immune responses...
July 8, 2017: Immunology Letters
https://www.readbyqxmd.com/read/28697551/n-acyl-homoserine-lactone-dynamics-during-biofilm-formation-of-a-1-2-4-trichlorobenzene-mineralizing-community-on-clay
#19
Hongjie Sheng, Mourad Harir, Lisa A Boughner, Xin Jiang, Philippe Schmitt-Kopplin, Reiner Schroll, Fang Wang
In Gram-negative bacteria, quorum sensing systems are based on the N-acyl-homoserine lactone (AHL) molecule. The objective of this study was to investigate the role of quorum sensing systems during biofilm formation by a microbial community while degrading the pollutant. Our model system included 1,2,4-trichlorobenzene (1,2,4-TCB) and its mineralizing Gram-negative bacterial community to investigate the relationships between AHL dynamics, cell growth and pollutant degradation. Biomineralization of 1,2,4-TCB was monitored for both the planktonic bacterial community with and without sterile clay particles in liquid cultures...
July 6, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28695853/crystal-structure-of-the-n-terminal-domain-of-vqsr-from-pseudomonas-aeruginosa-at-2-1%C3%A2-%C3%A3-resolution
#20
Qing He, Kang Wang, Tiantian Su, Feng Wang, Lichuan Gu, Sujuan Xu
VqsR is a quorum-sensing (QS) transcriptional regulator which controls QS systems (las, rhl and pqs) by directly downregulating the expression of qscR in Pseudomonas aeruginosa. As a member of the LuxR family of proteins, VqsR shares the common motif of a helix-turn-helix (HTH)-type DNA-binding domain at the C-terminus, while the function of its N-terminal domain remains obscure. Here, the crystal structure of the N-terminal domain of VqsR (VqsR-N; residues 1-193) was determined at a resolution of 2.1 Å...
July 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
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