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Quorum sensing

Şivge Kurgan, Shevali Kansal, Daniel Nguyen, Danielle Stephens, Yannis Koroneos, Hatice Hasturk, Thomas E Van Dyke, Alpdogan Kantarci
BACKGROUND: Neutrophil function is critical for the initiation and progression of infecto-inflammatory diseases. Key quorum-sensing plaque bacteria such as Fusobacterium nucleatum act as bridging species between early and late colonizer pathogens such as Porphyromonas gingivalis as the biofilm ages and periodontal inflammation increases. This study was designed to determine the impact of different F. nucleatum strains on neutrophil function. MATERIALS AND METHODS: HL-60 cells were differentiated into neutrophil-like cells and cultured with F...
October 20, 2016: Journal of Periodontology
H Y Shi, Q D Li, X Y Wan
Objective: To investigate the destructive effects of erythromycin on biofilm of MRSA and find the effect of erythromycin on QS related factors. Methods: Tested the MBC of erythromycin on MRSA.Established the model of biofilm.Erythromycin was added into the medium when bacteria were inoculated for 24 h. Tested the biofilm and collected the supernatant or serum of rat at 6, 12, 24, 48, 72 h and 7 d after adding erythromycin to detect the concentration of autoinducing peptides (AIP). Results: The MBC of the erythromycin on standard strains of MRSA was 256 g/L...
October 11, 2016: Zhonghua Yi Xue za Zhi [Chinese medical journal]
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
Darja Kušar, Karin Šrimpf, Petra Isaković, Lina Kalšek, Javid Hosseini, Irena Zdovc, Tina Kotnik, Modest Vengušt, Gabrijela Tavčar-Kalcher
BACKGROUND: Bacterial intercellular communication, called quorum sensing, takes place via the production and collective response to signal molecules. In Gram-negative bacteria, like Pseudomonas aeruginosa, these signaling molecules are N-acylhomoserine lactones (AHLs). P. aeruginosa is a common cause of inflammation of the ear canal (otitis externa) in dogs. It employs quorum sensing to coordinate the expression of host tissue-damaging factors, which are largely responsible for its virulence...
October 18, 2016: BMC Veterinary Research
Xiao Yu Liang, Xiaoyue Yu, Xiayan Pan, Jian Wu, Yabing Duan, Jianxin Wang, Mingguo Zhou
Thiazole, isothiazole, thiadiazole, and their derivatives are widely thought to induce host defenses against plant pathogens. However, this article reports that bismerthiazol, a thiadiazole molecule, reduces disease by inhibiting the histidine utilization (Hut) pathway and quorum sensing (QS). Bismerthiazol provides excellent control of bacterial rice leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) but does not greatly inhibit Xoo growth in vitro. According to RNA-seq analysis, transcription of Hut pathway genes of Xoo ZJ173 was inhibited after 4...
October 18, 2016: Molecular Plant Pathology
Feifei Cheng, Anzhou Ma, Guoqiang Zhuang, Rupert G Fray
In order to cope with pathogens, plants have evolved sophisticated mechanisms to sense pathogenic attacks and to induce defence responses. The N-acyl-homoserine lactone (AHL)-mediated quorum sensing in bacteria regulates diverse physiological processes including those involved in pathogenicity. In this work, we study the interactions between AHL-producing transgenic tobacco plants and Pseudomonas syringae pv. tabaci 11528 (P. syringae 11528). Both a reduced incidence of disease and decrease in the growth of P...
October 18, 2016: Molecular Plant Pathology
Mahendra Kumar Prajapat, Isha Shroff, R G Brajesh, Supreet Saini
Cooperation benefits individual cells in a microbial population by helping accomplish tasks which are difficult or non-beneficial for individuals in the population to carry out by themselves. Hence, numerous examples exist of bacteria cooperating and working towards a common objective. The sharing of a common public good via quorum sensing is one of the ways of cooperation among individuals of many microbial populations. However, cheaters exploit cooperators in a population by not contributing to the production of the common goods but enjoy benefits from goods secreted by cooperating individuals...
October 18, 2016: Molecular BioSystems
Bobbi Xayarath, Nancy E Freitag
A number of bacterial pathogens are capable of detecting the presence of other bacteria located within their surrounding niche through a process of bacterial signaling and cell-to-cell communication commonly referred to as quorum sensing (QS). QS systems are commonly now described in the context of collective behaviors exhibited by groups of bacteria coordinating diverse arrays of physiological functions to enhance survival of the community. However, QS systems have also been implicated in a variety of processes distinct from the measure of bacterial cell density...
October 18, 2016: Future Microbiology
Jumpei F Yamagishi, Nen Saito, Kunihiko Kaneko
As cells grow and divide under a given environment, they become crowded and resources are limited, as seen in bacterial biofilms and multicellular aggregates. These cells often show strong interactions through exchanging chemicals, as evident in quorum sensing, to achieve mutualism and division of labor. Here, to achieve stable division of labor, three characteristics are required. First, isogenous cells differentiate into several types. Second, this aggregate of distinct cell types shows better growth than that of isolated cells without interaction and differentiation, by achieving division of labor...
October 2016: PLoS Computational Biology
Nikolas T Weissmueller, Hoang Dung Lu, Amanda Hurley, Robert K Prud'homme
One factor limiting the expansion of nanomedicines has been the high cost of the materials and processes required for their production. We present a continuous, scalable, low cost nano-encapsulation process, Flash Nanoprecipitation (FNP) that enables the production of nanocarriers (NCs) with a narrow size distribution using zein corn proteins. Zein is a low cost, GRAS protein (having the FDA status of "Generally Regarded as Safe") currently used in food applications, which acts as an effective encapsulant for hydrophobic compounds using FNP...
October 16, 2016: Biomacromolecules
Faten K Abd El-Hady, Walid Fayad, Carmine Iodice, Zeinab A El-Shahid, Mohamed S Abdel-Aziz, Egle Crudele, Giuseppina Tommonaro
Marine organisms have been considered as the richest sources of novel bioactive metabolites, which can be used for pharmaceutical purposes. In the last years, the interest for marine microorganisms has grown for their enormous biodiversity and for the evidence that many novel compounds isolated from marine invertebrates are really synthesized by their associated bacteria. Nevertheless, the discovery of a chemical communication Quorum sensing (QS) between bacterial cells and between bacteria and host has gained the researchers to expand the aim of their study toward the role of bacteria associated with marine invertebrates, such as marine sponge...
October 14, 2016: Current Microbiology
Andrew G Palmer, Arijit Mukherjee, Danielle M Stacy, Stephen Lazar, Jean-Michel Ané, Helen E Blackwell
Density-dependent phenotypic switching in bacteria, the phenomenon of quorum sensing (QS), is instrumental in many pathogenic and mutualistic behaviors. In many Gram-negative bacteria, QS is regulated by N-acylated-l-homoserine lactones (AHLs). Synthetic analogues of these AHLs hold significant promise for regulating QS at the host-symbiont interface. Regulation depends on refined temporal and spatial models of quorums under native conditions. Critical to this is an understanding of how the presence of these signals may affect a prospective host...
October 14, 2016: Chembiochem: a European Journal of Chemical Biology
Kannan Rama Devi, Ramanathan Srinivasan, Arunachalam Kannappan, Sivasubramanian Santhakumari, Murugan Bhuvaneswari, Periyannan Rajasekar, Narayanan Marimuthu Prabhu, Arumugam Veera Ravi
Rosmarinic acid (RA) was assessed for its quorum sensing inhibitory (QSI) potential against Aeromonas hydrophila strains AH 1, AH 12 and MTCC 1739. The pathogenic strains of A. hydrophila were isolated from infected zebrafish and identified through biochemical analysis and amplification of a species-specific gene (rpsL). The biofilm inhibitory concentration (BIC) of RA against A. hydrophila strains was found to be 750 μg ml(-1). At this concentration, RA reduced the QS mediated hemolysin, lipase and elastase production in A...
November 2016: Biofouling
Guopeng Wei, Chieh Lo, Connor Walsh, N Luisa Hiller, Radu Marculescu
As understanding of bacterial regulatory systems and pathogenesis continues to increase, QSI has been a major focus of research. However, recent studies have shown that mechanisms of resistance to quorum sensing (QS) inhibitors (QSIs) exist, calling into question their clinical value. We propose a computational framework that considers bacteria genotypes relative to QS genes and QS-regulated products including private, quasi-public, and public goods according to their impacts on bacterial fitness. Our results show (1) QSI resistance spreads when QS positively regulates the expression of private or quasi-public goods...
October 13, 2016: Scientific Reports
Rémi Peyraud, Ludovic Cottret, Lucas Marmiesse, Jérôme Gouzy, Stéphane Genin
Bacterial pathogenicity relies on a proficient metabolism and there is increasing evidence that metabolic adaptation to exploit host resources is a key property of infectious organisms. In many cases, colonization by the pathogen also implies an intensive multiplication and the necessity to produce a large array of virulence factors, which may represent a significant cost for the pathogen. We describe here the existence of a resource allocation trade-off mechanism in the plant pathogen R. solanacearum. We generated a genome-scale reconstruction of the metabolic network of R...
October 2016: PLoS Pathogens
Andreas Thomann, Christian Brengel, Carsten Börger, Dagmar Kail, Anke Steinbach, Martin Empting, Rolf W Hartmann
Drug-resistant Pseudomonas aeruginosa (PA) strains are on the rise, making treatment with current antibiotics ineffective. Hence, circumventing resistance or restoring the activity of antibiotics by novel approaches is of high demand. Targeting the Pseudomonas quinolone signal quorum sensing (PQS-QS) system is an intriguing strategy to abolish PA pathogenicity without affecting the viability of the pathogen. Herein we report the structure-activity relationships of 2-sulfonylpyrimidines, which were previously identified as dual-target inhibitors of the PQS receptor PqsR and the PQS synthase PqsD...
October 12, 2016: ChemMedChem
Serena Ammendola, Ylenia D'Amico, Barbara Chirullo, Rosanna Drumo, Domenico Civardelli, Paolo Pasquali, Andrea Battistoni
Zinc is known to play a central role in bacterial physiology and pathogenesis. Here, we report that the accumulation of FliC, the structural subunit of Salmonella phase 1 flagella, is sharply reduced in a znuABC Salmonella enterica sv. Typhimurium strain grown in zinc-poor media. Consequently, this mutant strain lacks motility, unless it grows in zinc-replete environments. This phenotype is the consequence of a general downregulation of all the genes involved in the biosynthesis of flagella, suggesting that zinc is the cofactor of proteins involved in the initiation of the transcriptional regulatory cascade leading to flagella assembly...
October 1, 2016: Metallomics: Integrated Biometal Science
Yohei Tashiro, Yuki Kimura, Maiko Furubayashi, Akira Tanaka, Kei Terakubo, Kyoichi Saito, Shigeko Kawai-Noma, Daisuke Umeno
LuxR family transcriptional regulators are the core components of quorum sensing in Gram-negative bacteria and exert their effects through binding to the signaling molecules acyl-homoserine lactones (acyl-HSLs). The function of the LuxR homologs is remarkably plastic, and naturally occurring acyl-HSLs are structurally diverse. To investigate the molecular basis of the functional plasticity of Vibrio fischeri LuxR, we directed the evolution of LuxR toward three different specificities in the laboratory. We found an orthogonal pair of LuxR mutants specific either to 3-oxo-hexanoyl homoserine lactone or to 3-oxo-octanoyl homoserine lactone...
October 3, 2016: Journal of General and Applied Microbiology
Ramanathan Srinivasan, Kannan Rama Devi, Arunachalam Kannappan, Shunmugiah Karutha Pandian, Arumugam Veera Ravi
ETHNOPHARMACOLOGICAL RELEVANCE: Piper betle, a tropical creeper plant belongs to the family Piperaceae. The leaves of this plant have been well known for their therapeutic, religious and ceremonial value in South and Southeast Asia. It has also been reported to possess several biological activities including antimicrobial, antioxidant, antinociceptive, antidiabetic, insecticidal and gastroprotective activities and used as a common ingredient in indigenous medicines. In Indian system of ayurvedic medicine, P...
October 6, 2016: Journal of Ethnopharmacology
Marie Chantal Lemfack, Srinivasa Rao Ravella, Nicola Lorenz, Marco Kai, Kirsten Jung, Stefan Schulz, Birgit Piechulla
The skin microbiota is import for body protection. Here we present the first comprehensive analysis of the volatile organic compound (VOC) profiles of typical skin-resident corynebacterial and staphylococcal species. The VOC profile of Staphylococcus schleiferi DSMZ 4807 was of particular interest as it is dominated by two compounds, 3-(phenylamino)butan-2-one and 3-(phenylimino)butan-2-one (schleiferon A and B, respectively). Neither of these has previously been reported from natural sources. Schleiferon A and B inhibited the growth of various Gram-positive species and affected two quorum-sensing-dependent phenotypes - prodigiosin accumulation and bioluminescence - of Gram-negative bacteria...
September 27, 2016: Systematic and Applied Microbiology
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