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Jamuna Bai A, Ravishankar Rai V
Quorum sensing or cell to cell communication which includes inter- and intra-cellular communication has been implicated in the production of virulence factor and formation of biofilm in food-borne pathogens. In the present study, the effect of quorum sensing signals on the biofilms of food-borne pathogens has been elucidated. N-butryl homoserine lactone and N-hexanoyl homoserine lactone belonging to acyl homoserine lactone (AHL) family of signaling molecules were investigated for their effect on the biofilm formation (attachment and exopolymeric substance production) in the food-borne pathogens Escherichia coli, Salmonella enterica serovar Typhimurium and Vibrio parahemolyticus...
September 2016: Journal of Food Science and Technology
Sedef Ilk, Necdet Sağlam, Mustafa Özgen, Feza Korkusuz
Quorum sensing (QS) is a cell density dependent expression of species in bacteria mediated by compounds called autoinducers (AI). Several processes responsible for successful establishment of bacterial infection are mediated by QS. Inhibition of QS is therefore being considered as a new target for antimicrobial chemotherapy. Flavonoid compounds are strong antioxidant and antimicrobial agents but their applications are limited due to their poor dissolution and bioavailability. Our objective was to investigate the effect of kaempferol loaded chitosan nanoparticles on modulating QS mediated by AI in model bioassay test systems...
October 21, 2016: International Journal of Biological Macromolecules
Noora Tuomilehto, Reetta Kivisaari, Antti Sommarhem, Aarno Y Nietosvaara
Background and purpose - The quality of pin fixation of displaced supracondylar humerus fractures in children has not been assessed, and the clinical value of radiographic examinations after pin fixation is unclear. We evaluated pin configuration, quality of osteosynthesis, and outcome in 264 supracondylar fractures. The clinical significance of postoperative radiographs was analyzed. Patients and methods - 252 Gartland-III and 12 flexion-type supracondylar humerus fractures were pin-fixed in the periods 2002-2006 and 2012-2014...
October 24, 2016: Acta Orthopaedica
Monika S Brill, Tatjana Kleele, Laura Ruschkies, Mengzhe Wang, Natalia A Marahori, Miriam S Reuter, Torben J Hausrat, Emily Weigand, Matthew Fisher, Andrea Ahles, Stefan Engelhardt, Derron L Bishop, Matthias Kneussel, Thomas Misgeld
Developmental axon remodeling is characterized by the selective removal of branches from axon arbors. The mechanisms that underlie such branch loss are largely unknown. Additionally, how neuronal resources are specifically assigned to the branches of remodeling arbors is not understood. Here we show that axon branch loss at the developing mouse neuromuscular junction is mediated by branch-specific microtubule severing, which results in local disassembly of the microtubule cytoskeleton and loss of axonal transport in branches that will subsequently dismantle...
October 18, 2016: Neuron
Louise E Dixon, Emily Ahles, Luana Marques
Racial and ethnic minorities are at high risk for developing posttraumatic stress disorder (PTSD) after experiencing a traumatic event and are less likely to receive evidence-based treatment for their symptoms. There is a growing body of literature showing that culturally appropriate interventions result in greater uptake, symptom reduction, and sustained treatment gains. This article review explores new findings in the cultural understanding of PTSD among racial and ethnic minorities. We first review recent advances in the understanding of PTSD symptomotology...
December 2016: Current Psychiatry Reports
Mordjane Boukhet, Fabien Piguet, Hadjer Ouldali, Manuela Pastoriza-Gallego, Juan Pelta, Abdelghani Oukhaled
The transport of macromolecules through nanopores is involved in many biological functions and is today at the basis of promising technological applications. Nevertheless the interpretation of the dynamics of the macromolecule/nanopore interaction is still misunderstood and under debate. At the nanoscale, inside biomimetic channels under an external applied voltage, electrophoresis, which is the electric force acting on electrically charged molecules, and electroosmotic flow (EOF), which is the fluid transport associated with ions, contribute to the direction and magnitude of the molecular transport...
October 20, 2016: Nanoscale
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
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
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
Richard E Ahl, Frank C Keil
Four studies explored the abilities of 80 adults and 180 children (4-9 years), from predominantly middle-class families in the Northeastern United States, to use information about machines' observable functional capacities to infer their internal, "hidden" mechanistic complexity. Children as young as 4 and 5 years old used machines' numbers of functions as indications of complexity and matched machines performing more functions with more complex "insides" (Study 1). However, only older children (6 and older) and adults used machines' functional diversity alone as an indication of complexity (Studies 2-4)...
September 26, 2016: Child Development
Niharika Singh, Amrita Patil, Asmita Prabhune, Mamta Raghav, Gunjan Goel
The present study investigates the role of quorum sensing (QS) molecules expressed by C. sakazakii in biofilm formation and extracellular polysaccharide expression. The QS signaling was detected using Chromobacterium violaceum 026 and Agrobacterium tumefaciens NTL4(pZLR4) based bioassay. Long chain N-acyl-homoserine lactones (AHLs) with C6- C18 chain length were identified using High Performance Liquid Chromatography and Liquid Chromatography-High Resolution Mass Spectrometry. A higher Specific Biofilm Formation (SBF) index (p < 0...
October 7, 2016: Virulence
Nishaben M Patel, Joseph D Moore, Helen E Blackwell, Daniel Amador-Noguez
N-acyl L-homoserine lactones (AHLs) constitute a predominant class of quorum-sensing signaling molecules used by Gram-negative bacteria. Here, we report a sensitive and non-targeted HPLC-MS/MS method based on parallel reaction monitoring (PRM) to identify and quantitate known, unanticipated, and novel AHLs in microbial samples. Using a hybrid quadrupole-high resolution mass analyzer, this method integrates MS scans and all-ion fragmentation MS/MS scans to allow simultaneous detection of AHL parent-ion masses and generation of full mass spectra at high resolution and high mass accuracy in a single chromatographic run...
2016: PloS One
José A Jamangapé O, Ernesto Velázquez-Velázquez, Emilio Martínez-Ramirez, Manuel J Anzueto-Calvo, Eyda L Gomez, Sara E Dominguez-Cisneros, Caleb D Mcmahan, Wilfredo A Matamoros
Profundulus balsanus was described by Ahl in 1935 and later placed in synonymy with P. punctatus. Recent molecular studies have demonstrated that specimens identified as P. balsanus belong to a distinct taxon. Herein we used a combination of morphometric, meristic, coloration and osteological data in order to demonstrate the distinctiveness of P. balsanus. Additionally, we used molecular data to reconstruct a phylogeny to place P. balsanus in a systematic context. Profundulus balsanus belongs to the punctatus clade within the genus Profundulus...
October 2, 2016: Zootaxa
Sigde Mamani, Danielle Moinier, Yann Denis, Laurent Soulère, Yves Queneau, Emmanuel Talla, Violaine Bonnefoy, Nicolas Guiliani
While a functional quorum sensing system has been identified in the acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 23270(T) and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in A. ferrooxidans (T), the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL (N-acyl homoserine lactones) analog has been studied...
2016: Frontiers in Microbiology
Yan Wang, Qinghao Song, Xiao-Hua Zhang
Marine microorganisms produce a series of promising enzymes that have been widely used or are potentially valuable for our daily life. Both classic and newly developed biochemistry technologies have been broadly used to study marine and terrestrial microbiological enzymes. In this brief review, we provide a research update and prospects regarding regulatory mechanisms and related strategies of acyl-homoserine lactones (AHL) lactonase, which is an important but largely unexplored enzyme. We also detail the status and catalytic mechanism of the main types of polysaccharide-degrading enzymes that broadly exist among marine microorganisms but have been poorly explored...
2016: Marine Drugs
Franklin L Zhong, Ons Mamaï, Lorenzo Sborgi, Lobna Boussofara, Richard Hopkins, Kim Robinson, Ildikó Szeverényi, Takuya Takeichi, Reshmaa Balaji, Aristotle Lau, Hazel Tye, Keya Roy, Carine Bonnard, Patricia J Ahl, Leigh Ann Jones, Paul Baker, Lukas Lacina, Atsushi Otsuka, Pierre R Fournie, François Malecaze, E Birgitte Lane, Masashi Akiyama, Kenji Kabashima, John E Connolly, Seth L Masters, Vincent J Soler, Salma Samir Omar, John A McGrath, Roxana Nedelcu, Moez Gribaa, Mohamed Denguezli, Ali Saad, Sebastian Hiller, Bruno Reversade
Inflammasome complexes function as key innate immune effectors that trigger inflammation in response to pathogen- and danger-associated signals. Here, we report that germline mutations in the inflammasome sensor NLRP1 cause two overlapping skin disorders: multiple self-healing palmoplantar carcinoma (MSPC) and familial keratosis lichenoides chronica (FKLC). We find that NLRP1 is the most prominent inflammasome sensor in human skin, and all pathogenic NLRP1 mutations are gain-of-function alleles that predispose to inflammasome activation...
September 22, 2016: Cell
Magdy Abdalla Sayed El-Ahl, Mohammad Waheed El-Anwar
The aim of this study was to introduce and assess a new minimally invasive expansion pharyngoplasty for obstructive sleep apnea (OSA) using bilateral new advancement sutures without tonsillectomy. Among 24 patients who had OSA with Friedman stage II or III and type I Fujita, bilateral sutures were performed to advance and stabilize palatopharyngeus and palatoglossus muscles anterolaterally. Mean apnea hypopnea index decreased significantly from 28.6 ± 4.2 preoperatively to 8.9 ± 4.9 postoperatively. The lowest oxygen saturation increased significantly from 79...
September 20, 2016: Otolaryngology—Head and Neck Surgery
James John, Rajagopalan Saranathan, Lakshmi Narayana Adigopula, Vasanth Thamodharan, Satya Prakash Singh, T Pragna Lakshmi, Mallu Abhiram CharanTej, R Srinivasa Rao, R Krishna, H Surya Prakash Rao, K Prashanth
Secretory N-acyl homoserine lactones (AHLs) mediate quorum sensing (QS) in bacteria. AHLs are shown to be inhibitory for an unrelated group of bacteria and might mimic host signalling elements, thereby subverting the regulatory events in host cells. This study investigated the AHL produced by Acinetobacter baumannii and analysed its effect on other bacterial species and mammalian cells. Chemically characterized AHL had an m/z value of 325 with a molecular formula C18H31NO4 and showed its inhibitory potential against Staphylococcus aureus...
October 2016: Biofouling
Shelly L Pringle, Kelli L Palmer, Robert J C McLean
Escherichia coli lives in the gastrointestinal tract and elsewhere, where it coexists within a mixed population. Indole production enables E. coli to grow with other gram-negative bacteria as indole inhibits N-acyl-homoserine lactone (AHL) quorum regulation. We investigated whether E. coli indole production enhanced competition with gram-positive Enterococcus faecalis, wherein quorum signaling is mediated by small peptides. During planktonic co-culture with E. faecalis, the fitness and population density of E...
September 16, 2016: Archives of Microbiology
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