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Quorum sensing

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https://www.readbyqxmd.com/read/28921772/interplay-of-classic-exp-and-specific-vfm-quorum-sensing-systems-on-the-phenotypic-features-of-dickeya-solani-strains-exhibiting-different-virulence-levels
#1
Marta Potrykus, Nicole Hugouvieux-Cotte-Pattat, Ewa Lojkowska
Bacteria from the genus Dickeya cause severe symptoms on numerous economically important plants. D. solani is the Dickeya species most frequently found on infected potato plants in Europe. D. solani strains from different countries show high genetic homogeneity but significant differences in their virulence level. Dickeya species possess two quorum sensing (QS) mechanisms: the Exp system based on classic N-acyl-homoserine lactone (AHL) signals and a specific system depending on the production and perception of a molecule of unknown structure, Virulence Factor Modulating (VFM)...
September 18, 2017: Molecular Plant Pathology
https://www.readbyqxmd.com/read/28920855/pfma-a-novel-quorum-quenching-n-acylhomoserine-lactone-acylase-from-pseudoalteromonas-flavipulchra
#2
Na Liu, Min Yu, Youbin Zhao, Jingguang Cheng, Ke An, Xiao-Hua Zhang
Many bacteria, such as Proteobacteria, Cyanobacteria and Bacteroidetes, use N-acylhomoserine lactones (AHLs) as quorum-sensing (QS) signal molecules for communication. Enzymatic degradation of AHLs, such as AHL acylase and AHL lactonase, can degrade AHLs (quorum quenching, QQ) to attenuate or disarm the virulence of pathogens. QQ is confirmed to be common in marine bacterial communities. Many genes encoding AHL acylases are found in marine bacteria and metagenomic collections, but only a few of these have been characterized in detail...
September 18, 2017: Microbiology
https://www.readbyqxmd.com/read/28915909/differential-signal-sensitivities-can-contribute-to-the-stability-of-multispecies-bacterial-communities
#3
János Juhász, Dóra Bihary, Attila Jády, Sándor Pongor, Balázs Ligeti
BACKGROUND: Bacterial species present in multispecies microbial communities often react to the same chemical signal but at vastly different concentrations. The existence of different response thresholds with respect to the same signal molecule has been well documented in quorum sensing which is one of the best studied inter-cellular signalling mechanisms in bacteria. The biological significance of this phenomenon is still poorly understood, and cannot be easily studied in nature or in laboratory models...
September 15, 2017: Biology Direct
https://www.readbyqxmd.com/read/28913344/farnesol-inhibits-translation-to-limit-growth-and-filamentation-in-c-albicans-and-s-cerevisiae
#4
Nkechi E Egbe, Tawni O Dornelles, Caroline M Paget, Lydia M Castelli, Mark P Ashe
Candida albicans is a polymorphic yeast where the capacity to switch between yeast and filamentous growth is critical for pathogenicity. Farnesol is a quorum-sensing sesquiterpene alcohol that, via regulation of specific signalling and transcription components, inhibits filamentous growth in Candida albicans. Here we show that farnesol also inhibits translation at the initiation step in both Candida albicans and S. cerevisiae. In contrast to fusel alcohols, that target the eukaryotic initiation factor 2B (eIF2B), farnesol affects the interaction of the mRNA with the small ribosomal subunit leading to reduced levels of the 48S preinitiation ribosomal complex in S...
September 4, 2017: Microbial Cell
https://www.readbyqxmd.com/read/28912771/selection-of-functional-quorum-sensing-systems-by-lysogenic-bacteriophages-in-pseudomonas-aeruginosa
#5
Miguel A Saucedo-Mora, Paulina Castañeda-Tamez, Adrián Cazares, Judith Pérez-Velázquez, Burkhard A Hense, Daniel Cazares, Wendy Figueroa, Marco Carballo, Gabriel Guarneros, Berenice Pérez-Eretza, Nelby Cruz, Yoshito Nishiyama, Toshinari Maeda, Javier A Belmont-Díaz, Thomas K Wood, Rodolfo García-Contreras
Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28904418/leaf-extracts-of-selected-gardening-trees-can-attenuate-quorum-sensing-and-pathogenicity-of-pseudomonas-aeruginosa-pao1
#6
Kaimin Niu, Min Kuk, Haein Jung, Kokgan Chan, Sooki Kim
An increasing concern on resistance to multiple-antibiotics has led to the discovery of novel agents and the establishment of new precaution strategy. Numerous plant sources have been widely studied to reduce virulence of pathogenic bacteria by interfering cell-to-cell based communication called quorum sensing (QS). Leaf extracts of 17 gardening trees were collected and investigated for their anti-QS effects using a sensor strain Chromobacterium violaceum CV026. Methanolic extracts of K4 (Acer palmatum), K9 (Acer pseudosieboldianum) and K13 (Cercis chinensis) leaves were selected for further experiments based on their antagonism effect on QS without inhibiting C...
September 2017: Indian Journal of Microbiology
https://www.readbyqxmd.com/read/28902853/the-human-bitter-taste-receptor-t2r38-is-broadly-tuned-for-bacterial-compounds
#7
Christophe Verbeurgt, Alex Veithen, Sébastien Carlot, Maxime Tarabichi, Jacques E Dumont, Sergio Hassid, Pierre Chatelain
T2R38 has been shown to be a specific bacterial detector implicated in innate immune defense mechanism of human upper airway. Several clinical studies have demonstrated that this receptor is associated with the development of chronic rhinosinusitis (CRS). T2R38 was previously reported to bind to homoserine lactones (HSL), quorum sensing molecules specific of Pseudomonas Aeruginosa and other gram negative species. Nevertheless, these bacteria are not the major pathogens found in CRS. Here we report on the identification of bacterial metabolites acting as new agonists of T2R38 based on a single cell calcium imaging study...
2017: PloS One
https://www.readbyqxmd.com/read/28902851/redox-mediated-quorum-sensing-in-plants
#8
Alexandra W Fuller, Phoebe Young, B Daniel Pierce, Jamie Kitson-Finuff, Purvi Jain, Karl Schneider, Stephen Lazar, Olga Taran, Andrew G Palmer, David G Lynn
The rhizosphere, the narrow zone of soil around plant roots, is a complex network of interactions between plants, bacteria, and a variety of other organisms. The absolute dependence on host-derived signals, or xenognosins, to regulate critical developmental checkpoints for host commitment in the obligate parasitic plants provides a window into the rhizosphere's chemical dynamics. These sessile intruders use H2O2 in a process known as semagenesis to chemically modify the mature root surfaces of proximal host plants and generate p-benzoquinones (BQs)...
2017: PloS One
https://www.readbyqxmd.com/read/28902153/bacterial-biofilm-control-by-perturbation-of-bacterial-signaling-processes
#9
REVIEW
Tim Holm Jakobsen, Tim Tolker-Nielsen, Michael Givskov
The development of effective strategies to combat biofilm infections by means of either mechanical or chemical approaches could dramatically change today's treatment procedures for the benefit of thousands of patients. Remarkably, considering the increased focus on biofilms in general, there has still not been invented and/or developed any simple, efficient and reliable methods with which to "chemically" eradicate biofilm infections. This underlines the resilience of infective agents present as biofilms and it further emphasizes the insufficiency of today's approaches used to combat chronic infections...
September 13, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28900249/effect-of-efflux-pump-inhibition-on-pseudomonas-aeruginosa-transcriptome-and-virulence
#10
Giordano Rampioni, Cejoice Ramachandran Pillai, Francesca Longo, Roslen Bondì, Valerio Baldelli, Marco Messina, Francesco Imperi, Paolo Visca, Livia Leoni
Efflux pumps of the resistance-nodulation-cell-division (RND) family increase antibiotic resistance in many bacterial pathogens, representing candidate targets for the development of antibiotic adjuvants. RND pumps have also been proposed to contribute to bacterial infection, implying that efflux pump inhibitors (EPIs) could also act as anti-virulence drugs. Nevertheless, EPIs are usually investigated only for their properties as antibiotic adjuvants, while their potential anti-virulence activity is seldom taken into account...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28895513/cadmium-ion-inhibition-of-quorum-signalling-in-chromobacterium-violaceum
#11
Starla G Thornhill, Manish Kumar, Leticia M Vega, Robert J C McLean
Single-celled bacteria are capable of acting as a community by sensing and responding to population density via quorum signalling. Quorum signalling in Chromobacterium violaceum, mediated by the luxI/R homologue, cviI/R, regulates a variety of phenotypes including violacein pigmentation, virulence and biofilm formation. A number of biological and organic molecules have been described as quorum signalling inhibitors but, to date, metal-based inhibitors have not been widely tested. In this study, we show that quorum sensing is inhibited in C...
September 12, 2017: Microbiology
https://www.readbyqxmd.com/read/28894985/virulence-analysis-of-staphylococcus-aureus-in-a-rabbit-model-of-infected-full-thickness-wound-under-negative-pressure-wound-therapy
#12
Daohong Liu, Zhirui Li, Guoqi Wang, Tongtong Li, Lihai Zhang, Peifu Tang
The aim of this study was to evaluate the virulence of Staphylococcus aureus in a controlled animal study using the standard sterile gauze and negative pressure wound therapy (NPWT), including activation of agr, gene expression and production of virulence foctors and depth of bacterial invasion. The tissue specimens were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds. Laser scanning confocal microscopy was performed to obtain bioluminescent images which were used to measure the depth of bacterial invasion...
September 11, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28893777/modulation-of-staphylococcus-aureus-response-to-antimicrobials-by-the-candida-albicans-quorum-sensing-molecule-farnesol
#13
Eric F Kong, Christina Tsui, Sona Kucharíková, Patrick Van Dijck, Mary Ann Jabra-Rizk
In microbial biofilms, microorganisms utilize secreted signaling chemical molecules to coordinate their collective behavior. Farnesol is a quorum-sensing molecule secreted by the fungal species Candida albicans, shown to play a central physiological role during fungal biofilm growth. Our pervious in vitro and in vivo studies characterized an intricate interaction between C. albicans and the bacterial pathogen Staphylococcus aureus, as these species co-exist in biofilm. In this study, we aimed to investigate the impact of farnesol on S...
September 11, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28893374/cell-differentiation-defines-acute-and-chronic-infection-cell-types-in-staphylococcus-aureus
#14
Juan-Carlos García-Betancur, Angel Goñi-Moreno, Thomas Horger, Melanie Schott, Malvika Sharan, Julian Eikmeier, Barbara Wohlmuth, Alma Zernecke, Knut Ohlsen, Christina Kuttler, Daniel Lopez
A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia...
September 12, 2017: ELife
https://www.readbyqxmd.com/read/28892274/biosynthesis-and-function-of-simple-amides-in-xenorhabdus-doucetiae
#15
Edna Bode, Yue He, Tien Duy Vo, Roland Schultz, Marcel Kaiser, Helge B Bode
Xenorhabdus doucetiae, the bacterial symbiont of the entomopathogenic nematode Steinernema diaprepesi produces several different fatty acid amides. Their biosynthesis has been studied using a combination of analysis of gene deletions and promoter exchanges in X. doucetiae and heterologous expression of candidate genes in E. coli. While a decarboxylase is required for the formation of all observed phenylethylamides and tryptamides, the acyltransferase XrdE encoded in the xenorhabdin biosynthesis gene cluster is responsible for the formation of short chain acyl amides...
September 11, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28889735/small-molecule-potentiators-for-conventional-antibiotics-against-staphylococcus-aureus
#16
Arno Vermote, Serge Van Calenbergh
Antimicrobial resistance constitutes a global health problem, while the discovery and development of novel antibiotics is stagnating. Methicillin-resistant Staphylococcus aureus, responsible for the establishment of recalcitrant, biofilm-related infections, is a well known and notorious example of a highly resistant micro organism. Since resistance development is unavoidable with conventional antibiotics that target bacterial viability, it is vital to develop alternative treatment options on top. Strategies aimed at more subtle manipulation of bacterial behavior have recently attracted attention...
September 11, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28889264/metals-and-paraoxonases
#17
Lucio G Costa, Toby B Cole, Jacqueline M Garrick, Judit Marsillach, Clement E Furlong
The paraoxonases (PONs) are a three-gene family which includes PON1, PON2, and PON3. PON1 and PON3 are synthesized primarily in the liver and a portion is secreted in the plasma, where they are associated with high-density lipoproteins (HDLs), while PON2 is an intracellular enzyme, expressed in most tissues and organs, including the brain. PON1 received its name from its ability to hydrolyze paraoxon, the active metabolite of the organophosphorus (OP) insecticide parathion, and also more efficiently hydrolyzes the active metabolites of several other OPs...
2017: Advances in Neurobiology
https://www.readbyqxmd.com/read/28887768/population-model-of-quorum-sensing-with-multiple-parallel-pathways
#18
Gaoyang Fan, Paul C Bressloff
Quorum sensing (QS) is a bacterial communication mechanism that uses signal-receptor binding to regulate gene expression based on cell density, resulting in group behaviors such as biofilm formation, bioluminescence and stress response. In certain bacterial species such as Vibrio harveyi, several parallel QS signaling pathways drive a single phosphorylation-dephosphorylation cycle, which in turn regulates QS target genes. In this paper, we investigate the possible role of parallel signaling pathways by developing a mathematical model of QS in V...
September 8, 2017: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/28887424/a-survey-of-putative-quorum-sensing-genes-in-nitrifying-bacteria-reveals-acyl-homoserine-lactone-production-in-ammonia-and-nitrite-oxidizing-bacteria-from-the-genera-nitrosospira-nitrobacter-and-nitrospira
#19
Brett L Mellbye, Eva Spieck, Peter J Bottomley, Luis A Sayavedra-Soto
The genomes of many bacteria that participate in nitrogen cycling through the process of nitrification contain putative genes associated with acyl-homoserine lactone (AHL) quorum sensing (QS). AHL QS or bacterial cell-cell signaling is a method of bacterial communication and gene regulation and may be involved in nitrogen oxide fluxes or other important phenotypes in nitrifying bacteria. Here, we carried out a broad survey of AHL production in nitrifying bacteria in three steps. First, we analyzed the evolutionary history of AHL synthase and AHL receptor homologs in sequenced genomes and metagenomes of nitrifying bacteria to identify AHL synthase homologs in ammonia-oxidizing bacteria (AOB) of the genera Nitrosospira and nitrite-oxidizing bacteria (NOB) of the genera Nitrococcus, Nitrobacter, and Nitrospira Next, we screened cultures of both AOB and NOB cultures with uncharacterized AHL synthase genes and AHL synthase-negative nitrifiers by bioassay...
September 8, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28887169/in-vitro-and-in-vivo-exploration-of-palmitic-acid-from-synechococcus-elongatus-as-an-antibiofilm-agent-on-the-survival-of-artemia-franciscana-against-virulent-vibrios
#20
Sivasubramanian Santhakumari, Nizam Mohamed Nilofernisha, Jeyaraj Godfred Ponraj, Shunmugiah Karutha Pandian, Arumugam Veera Ravi
Biofilm formation of Vibrio spp. has been demonstrated as a potentially important mechanism contributing antibiotic treatment failure in aquaculture. In the present study, the effect of palmitic acid (PA) identified from Synechococcus elongatus was assessed for the inhibition of quorum sensing (QS) regulated biofilm formation in aquatic bacterial pathogens. The biofilm inhibitory concentration (BIC) of PA against Vibrio spp. was found to be 100µgml(-1). In this concentration, PA exhibited a significant inhibition in biofilm biomass of Vibrio harveyi MTCC 3438, V...
September 6, 2017: Journal of Invertebrate Pathology
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