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Quorum sensing

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https://www.readbyqxmd.com/read/29778469/communications-of-staphylococcus-aureus-and-non-aureus-staphylococcus-species-from-bovine-intramammary-infections-and-teat-apex-colonization
#1
Yasser S Mahmmod, Ilka Christine Klaas, Line Svennesen, Karl Pedersen, Hanne Ingmer
The role of non-aureus staphylococci (NAS) in the risk of acquisition of intramammary infections with Staphylococcus aureus is vague and still under debate. The objectives of this study were to (1) investigate the distribution patterns of NAS species from milk and teat skin in dairy herds with automatic milking systems, and (2) examine if the isolated NAS influences the expression of S. aureus virulence factors controlled by the accessory gene regulator (agr) quorum sensing system. In 8 herds, 14 to 20 cows with elevated somatic cell count were randomly selected for teat skin swabbing and aseptic quarter foremilk samples from right hind and left front quarters...
May 16, 2018: Journal of Dairy Science
https://www.readbyqxmd.com/read/29776924/tools-for-rapid-genetic-engineering-of-vibrio-fischeri
#2
Karen L Visick, Kelsey M Hodge-Hanson, Alice H Tischler, Allison K Bennett, Vincent Mastrodomenico
Vibrio fischeri is used as a model for number of processes, including symbiosis, quorum sensing, bioluminescence, and biofilm formation. Many of these studies depend on generating deletion mutants and complementing them. Engineering such strains, however, is a time-consuming, multi-step process that relies on cloning and subcloning. Here, we describe a set of tools that can be used to rapidly engineer deletions and insertions in the V. fischeri chromosome without cloning. We developed a uniform approach for generating deletions using PCR SOEing (Splicing by Overlap Extension) with antibiotic cassettes flanked by standardized linker sequences...
May 18, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29776923/environmental-adaptability-for-quorum-sensing-regulating-iron-uptake-during-biofilm-formation-in-paracoccus-denitrificans
#3
Yang Zhang, Jie Gao, Lushan Wang, Shuangjiang Liu, Zhihui Bai, Xuliang Zhuang, Guoqiang Zhuang
Paracoccus denitrificans is a valuable model organism due to its versatile respiration capability and bioenergetic flexibility, both of which are critical to its survival in different environments. Quorum sensing (QS) plays a crucial role in the regulation of many cell functions; however, whether QS systems play a role in P. denitrificans is unknown. In this study, we demonstrated that iron uptake systems in P. denitrificans were directly regulated by a newly identified QS system. Genes coding for TonB-dependent systems, which transport chelated iron, were transcribed at higher levels in the QS-defective mutants...
May 18, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29775480/titan-cells-formation-in-cryptococcus-neoformans-is-finely-tuned-by-environmental-conditions-and-modulated-by-positive-and-negative-genetic-regulators
#4
Benjamin Hommel, Liliane Mukaremera, Radames J B Cordero, Carolina Coelho, Christopher A Desjardins, Aude Sturny-Leclère, Guilhem Janbon, John R Perfect, James A Fraser, Arturo Casadevall, Christina A Cuomo, Françoise Dromer, Kirsten Nielsen, Alexandre Alanio
The pathogenic fungus Cryptococcus neoformans exhibits morphological changes in cell size during lung infection, producing both typical size 5 to 7 μm cells and large titan cells (> 10 μm and up to 100 μm). We found and optimized in vitro conditions that produce titan cells in order to identify the ancestry of titan cells, the environmental determinants, and the key gene regulators of titan cell formation. Titan cells generated in vitro harbor the main characteristics of titan cells produced in vivo including their large cell size (>10 μm), polyploidy with a single nucleus, large vacuole, dense capsule, and thick cell wall...
May 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29775477/cryptococcus-neoformans-can-form-titan-like-cells-in-vitro-in-response-to-multiple-signals
#5
Nuria Trevijano-Contador, Haroldo Cesar de Oliveira, Rocío García-Rodas, Suélen Andreia Rossi, Irene Llorente, Ángel Zaballos, Guilhem Janbon, Joaquín Ariño, Óscar Zaragoza
Cryptococcus neoformans is an encapsulated pathogenic yeast that can change the size of the cells during infection. In particular, this process can occur by enlarging the size of the capsule without modifying the size of the cell body, or by increasing the diameter of the cell body, which is normally accompanied by an increase of the capsule too. This last process leads to the formation of cells of an abnormal enlarged size denominated titan cells. Previous works characterized titan cell formation during pulmonary infection but research on this topic has been hampered due to the difficulty to obtain them in vitro...
May 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29775211/proanthocyanidins-will-they-effectively-restrain-conspicuous-bacterial-strains-devolving-on-urinary-tract-infection
#6
REVIEW
Venkataseshan Jagannathan, Pragasam Viswanathan
Struvite or infection stones are one of the major clinical burdens among urinary tract infection, which occur due to the interaction between microbes and urine mineral components. Numerous urinary tract infection (UTI) causing microbes regulate through biofilm formation for survival from host defense, it is often found difficult in its eradication with simple anti-microbial agents and also the chance of recurrence and resistance development is significantly high. Cranberry consumption and maintenance of urinary tract health have been supported by clinical, epidemiological, and mechanistic studies...
May 18, 2018: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/29773060/cyclic-peptides-that-govern-signal-transduction-pathways-from-prokaryotes-to-multi-cellular-organisms
#7
Ryan W Mull, Anthony Harrington, Lucia A Sanchez, Yftah Tal-Gan
Cyclic peptide scaffolds are key components of signal transduction pathways in both prokaryotic and eukaryotic organisms since they act as chemical messengers that activate or inhibit specific cognate receptors. In prokaryotic organisms these peptides are utilized in non-essential pathways, such as quorum sensing, that are responsible for virulence and pathogenicity. In the more evolved eukaryotic systems, cyclic peptide hormones play a key role in the regulation of the overall function of multicellular organisms, mainly through the endocrine system...
May 17, 2018: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/29767954/development-of-molecularly-imprinted-polymers-to-block-quorum-sensing-and-inhibit-bacterial-biofilm-formation
#8
Luyao Ma, Shaolong Feng, Cesar de la Fuente-Nunez, Robert E W Hancock, Xiaonan Lu
Bacterial biofilms are responsible for most clinical infections and show increased antimicrobial resistance. In this study, molecularly imprinted polymers (MIPs) were developed to specifically capture prototypical quorum sensing autoinducers [i.e., N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12AHL)], interrupt quorum sensing, and subsequently inhibit biofilm formation of Pseudomonas aeruginosa, an important human nosocomial pathogen. The synthesis of MIPs was optimized by considering the amount and type of the functional monomers itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA)...
May 16, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29765621/biofilm-inhibition-and-pathogenicity-attenuation-in-bacteria-by-proteus-mirabilis
#9
Shichen Yu, Xiaoshan Zhu, Jin Zhou, Zhonghua Cai
Biofilms play an important role in the antibiotic resistance of encased bacteria, and biofilm formation is regulated by quorum sensing (QS). Inhibiting the QS system may, therefore, degrade the integrity of a biofilm and expose the bacterial pathogens within it to the deleterious effects of molecules such as antibiotics. Moreover, the use of QS inhibitors (QSIs) may provide a novel approach for treating bacterial infections of aquacultures. In the present study, the bacterium Proteus mirabilis was identified as a potential producer of QSIs...
April 2018: Royal Society Open Science
https://www.readbyqxmd.com/read/29764942/could-positive-feedback-enable-bacterial-pheromone-signaling-to-coordinate-behaviors-in-response-to-heterogeneous-environmental-cues
#10
Eric V Stabb
Pheromone signaling (PS) underlies many important bacterial behaviors, yet its ecological functions remain unresolved. Because pheromone-mediated behaviors require high cell density, the term "quorum sensing" is widely used to describe and make sense of PS. However, while this term has unified and popularized the field, bacterial PS clearly has roles beyond census taking, and the complexities of PS circuits indicate broader functional capacities. Two common features of bacterial PS are its regulation in response to environmental conditions and positive-feedback loops...
May 15, 2018: MBio
https://www.readbyqxmd.com/read/29763730/virtual-screening-of-plant-compounds-and-nonsteroidal-anti-inflammatory-drugs-for-inhibition-of-quorum-sensing-and-biofilm-formation-in-salmonella
#11
Felipe Alves de Almeida, Erika Lorena Giraldo Vargas, Deisy Guimarães Carneiro, Uelinton Manoel Pinto, Maria Cristina Dantas Vanetti
Salmonella belongs to the Enterobacteriaceae family which is widely distributed in the environment due to its adaptive capacity to stress conditions. In addition, Salmonella is able to perform a type of cell-to-cell communication called quorum sensing, which leads to differential gene expression. The quorum sensing system mediated by AI-1, acyl homoserine lactones (AHLs), is incomplete in Salmonella because the luxI homolog gene, which encodes for AI-1 synthase, is missing in the genome. However, a homologue of LuxR, known as SdiA, is present and allows the detection of signaling molecules produced by other species of bacteria, leading to regulation of gene expression, mainly related to virulence and biofilm formation...
May 12, 2018: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29762495/role-of-sdia-on-biofilm-formation-by-atypical-enteropathogenic-escherichia-coli
#12
Hebert F Culler, Samuel C F Couto, Juliana S Higa, Renato M Ruiz, Min J Yang, Vanessa Bueris, Marcia R Franzolin, Marcelo P Sircili
Atypical enteropathogenic Escherichia coli are capable to form biofilm on biotic and abiotic surfaces, regardless of the adherence pattern displayed. Several E. coli mechanisms are regulated by Quorum sensing (QS), including virulence factors and biofilm formation. Quorum sensing is a signaling system that confers bacteria with the ability to respond to chemical molecules known as autoinducers. Suppressor of division inhibitor (SdiA) is a QS receptor present in atypical enteropathogenic E. coli (aEPEC) that detects acyl homoserine lactone (AHL) type autoinducers...
May 15, 2018: Genes
https://www.readbyqxmd.com/read/29760208/rpon-dependent-direct-regulation-of-quorum-sensing-and-the-type-vi-secretion-system-in-pseudomonas-aeruginosa-pao1
#13
Xiaolong Shao, Xiaoning Zhang, Yingchao Zhang, Miao Zhu, Pan Yang, Jian Yuan, Yingpeng Xie, Tianhong Zhou, Wei Wang, Sheng Chen, Haihua Liang, Xin Deng
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen of humans, particularly those with cystic fibrosis. As a global regulator, RpoN controls a group of virulence-related factors and quorum sensing (QS) genes in P. aeruginosa To further gain insights into the direct targets of RpoN in vivo , the present study focused on identifying the direct targets of RpoN regulation in QS and the type VI secretion system (T6SS). We performed a chromatin immunoprecipitation coupled to high-throughput sequencing (ChIP-seq) assay that identified 1,068 binding sites of RpoN, mostly including metabolic genes, a group of genes in QS ( lasI , rhlI and pqsR ) and the T6SS ( hcpA and hcpB )...
May 14, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29760087/-pseudomonas-aeruginosa-transcriptome-during-human-infection
#14
Daniel M Cornforth, Justine L Dees, Carolyn B Ibberson, Holly K Huse, Inger H Mathiesen, Klaus Kirketerp-Møller, Randy D Wolcott, Kendra P Rumbaugh, Thomas Bjarnsholt, Marvin Whiteley
Laboratory experiments have uncovered many basic aspects of bacterial physiology and behavior. After the past century of mostly in vitro experiments, we now have detailed knowledge of bacterial behavior in standard laboratory conditions, but only a superficial understanding of bacterial functions and behaviors during human infection. It is well-known that the growth and behavior of bacteria are largely dictated by their environment, but how bacterial physiology differs in laboratory models compared with human infections is not known...
May 14, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29756135/microbial-small-molecules-weapons-of-plant-subversion
#15
REVIEW
Ioannis A Stringlis, Hao Zhang, Corné M J Pieterse, Melvin D Bolton, Ronnie de Jonge
Covering: up to 2018Plants live in close association with a myriad of microbes that are generally harmless. However, the minority of microbes that are pathogens can severely impact crop quality and yield, thereby endangering food security. By contrast, beneficial microbes provide plants with important services, such as enhanced nutrient uptake and protection against pests and diseases. Like pathogens, beneficial microbes can modulate host immunity to efficiently colonize the nutrient-rich niches within and around the roots and aerial tissues of a plant, a phenomenon mirroring the establishment of commensal microbes in the human gut...
May 14, 2018: Natural Product Reports
https://www.readbyqxmd.com/read/29755959/pvdq-quorum-quenching-acylase-attenuates-pseudomonas-aeruginosa-virulence-in-a-mouse-model-of-pulmonary-infection
#16
Putri D Utari, Rita Setroikromo, Barbro N Melgert, Wim J Quax
Pseudomonas aeruginosa is the predominant pathogen in pulmonary infections associated with cystic fibrosis. Quorum sensing (QS) systems regulate the production of virulence factors and play an important role in the establishment of successful P. aeruginosa infections. Inhibition of the QS system (termed quorum quenching) renders the bacteria avirulent thus serving as an alternative approach in the development of novel antibiotics. Quorum quenching in Gram negative bacteria can be achieved by preventing the accumulation of N -acyl homoserine lactone (AHL) signaling molecule via enzymatic degradation...
2018: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29751512/screening-of-natural-product-derivatives-identifies-two-structurally-related-flavonoids-as-potent-quorum-sensing-inhibitors-against-gram-negative-bacteria
#17
Suvi Manner, Adyary Fallarero
Owing to the failure of conventional antibiotics in biofilm control, alternative approaches are urgently needed. Inhibition of quorum sensing (QS) represents an attractive target since it is involved in several processes essential for biofilm formation. In this study, a compound library of natural product derivatives ( n = 3040) was screened for anti-quorum sensing activity using Chromobacterium violaceum as reporter bacteria. Screening assays, based on QS-mediated violacein production and viability, were performed in parallel to identify non-bactericidal QS inhibitors (QSIs)...
May 3, 2018: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29750862/an-in-vitro-model-of-the-gram-negative-bacterial-cell-envelope-for-investigation-of-anti-infective-permeation-kinetics
#18
Florian Graef, Robert Richter, Verena Fetz, Xabier Murgia, Chiara De Rossi, Nicole Schneider-Daum, Giuseppe Allegretta, Walid A M Elgaher, Jörg Haupenthal, Martin Empting, Felix Beckmann, Mark Brönstrup, Rolf W Hartmann, Sarah Gordon, Claus-Michael Lehr
The cell envelope of Gram-negative bacteria is a formidable biological barrier, inhibiting the action of antibiotics by impeding their permeation into the intracellular environment. In-depth understanding of permeation through this barrier remains a challenge, despite its critical role in antibiotic activity. We therefore designed a divisible in vitro permeation model of the Gram-negative bacterial cell envelope, mimicking its three essential structural elements - the inner membrane, the periplasmic space as well as the outer membrane - on a Transwell® setup...
May 11, 2018: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29750509/microbial-nitrogen-cycle-hotspots-in-the-plant-bed-ditch-system-of-a-constructed-wetland-with-n2o-mitigation
#19
Shanyun Wang, Weidong Wang, Lu Liu, Linjie Zhuang, Siyan Zhao, Yu Su, Yixiao Li, Mengzi Wang, Cheng Wang, Liya Xu, Guibing Zhu
Artificial microbial nitrogen (N) cycle hotspots in the plant-bed/ditch system were developed and investigated based on intact core and slurry assays measurement using isotopic tracing technology, quantitative PCR and high-throughput sequencing. By increasing hydraulic retention time and periodically fluctuating water level in heterogeneous riparian zones, hotspots of anammox, nitrification, denitrification, ammonium (NH4+) oxidation, nitrite (NO2-) oxidation, nitrate (NO3-) reduction and DNRA were all stimulated at the interface sediments, with the abundance and activity being about 1-3 orders higher than that in non-hotspot zones...
May 11, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29748385/activation-of-airway-epithelial-bitter-taste-receptors-by-pseudomonas-aeruginosa-quinolones-modulates-calcium-cyclic-amp-and-nitric-oxide-signaling
#20
Jenna R Freund, Corrine J Mansfield, Laurel J Doghramji, Nithin D Adappa, James N Palmer, David W Kennedy, Danielle R Reed, Peihua Jiang, Robert J Lee
Bitter taste receptors (T2Rs), discovered in many tissues outside the tongue, have recently become potential therapeutic targets. We showed previously that airway epithelial cells express several T2Rs that activate innate immune responses that may be important for treatment of airway diseases such as chronic rhinosinusitis. It is imperative to more clearly understand what compounds activate airway T2Rs as well as their full range of functions. T2R isoforms in airway motile cilia (T2Rs 4, 14, 16, and 38) produce bactericidal levels of nitric oxide (NO) that also increase ciliary beating, promoting clearance of mucus and trapped pathogens...
May 10, 2018: Journal of Biological Chemistry
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