oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 44 )

2018 ( 187 )

2017 ( 220 )

2016 ( 224 )

Custom range...

Search Results: 1 - 10 of 6218 matches for " Quorum-Sensing Inhibitor "
All listed articles are free for downloading (OA Articles)
Page 1 /6218
Display every page Item
N,N’-alkylated Imidazolium-Derivatives Act as Quorum-Sensing Inhibitors Targeting the Pectobacterium atrosepticum-Induced Symptoms on Potato Tubers
Yannick Raoul des Essarts,Mohamad Sabbah,Arnaud Comte,Laurent Soulère,Yves Queneau,Yves Dessaux,Valérie Hélias,Denis Faure
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms141019976
Abstract: Bacteria belonging to the Pectobacterium genus are the causative agents of the blackleg and soft-rot diseases that affect potato plants and tubers worldwide. In Pectobacterium, the expression of the virulence genes is controlled by quorum-sensing (QS) and N-acylhomoserine lactones (AHLs). In this work, we screened a chemical library of QS-inhibitors (QSIs) and AHL-analogs to find novel QSIs targeting the virulence of Pectobacterium. Four N, N’-bisalkylated imidazolium salts were identified as QSIs; they were active at the μM range. In potato tuber assays, two of them were able to decrease the severity of the symptoms provoked by P. atrosepticum. This work extends the range of the QSIs acting on the Pectobacterium-induced soft-rot disease.
Piericidins, Novel Quorum-Sensing Inhibitors against Chromobacterium violaceum CV026, from Streptomyces sp. TOHO-Y209 and TOHO-O348  [PDF]
Kazuhiro Ooka, Atsushi Fukumoto, Tomoe Yamanaka, Kanako Shimada, Ryo Ishihara, Yojiro Anzai, Fumio Kato
Open Journal of Medicinal Chemistry (OJMC) , 2013, DOI: 10.4236/ojmc.2013.34012
Abstract: Piericidin A1, 3’-rhamnopiericidin A1, and a novel compound piericidin E, a new quorum-sensing (QS) inhibitor
against Chromobacterium violaceum CV026, were isolated from the culture broth of Streptomyces sp. QS is well
known as a microbial signaling system and controls certain types of gene expression resulting in bioluminescence,
biofilm formation, swarming motility, antibiotic biosynthesis, and virulence factor production. C. violaceum CV026 is
commonly used to determine qualitative and quantitative QS activity. The structures of piericidin derivatives were characterized,
and their QS activities were determined.
Bioinformatics Analysis of NprR-NprX Quorum-Sensing System of Bacillus thuringiensis Isolates from the Papaloapan Region, Oaxaca-Mexico  [PDF]
Humberto Rafael Bravo-D, Alain Cruz-Nolasco, Luis Raúl Gutiérrez-Lucas, Ana Karin Navarro-Mtz
Advances in Biological Chemistry (ABC) , 2015, DOI: 10.4236/abc.2015.57027
Abstract: Quorum sensing is a chemical communication process that bacteria use to regulate collective behaviors. In Gram-positive bacteria, oligopeptides (called autoinducers) are the signaling molecules to elicit quorum sensing. In Bacillus thuringiensis, NprR is a transcriptional regulator whose activity depends on the NprX signalling peptide. Bacillus thuringiensis is closely related to Bacillus cereus and Bacillus anthracis. The principal difference between them is that Bacillus thuringiensis is the only one that produced Cry protein. The aim of this study is to explore the relation of nprR and 16S rRNA genes in Bacillus thurin-giensis. Phylogenetic trees of nucleotide sequences of nprR and 16S rRNA genes were built. Sequences of fourteen new isolates from Papaloapan region were included in those phylo-genetic trees. In order to identify the isolates, a simple and fast methodology considering the Cry protein formation was used. The 16S rRNA phylogenetic tree allows identify eight isolates as Bacillus thuringiensis and the others as Bacillus spp. The nprR phylogenetic tree does not match with the 16S rRNA phylogenetic tree. This confirms that nprR is not a molecular marker for evolution. Most of the new isolates have the same NprR sequence (WTSDIVG). However, the SKPDIVG is the most common NprR sequence in thuringiensis species.
Prevalence of agr specificity groups among Staphylococcus aureus strains isolated from different clinical specimens patients with cardiovascular surgery associated infections
Ani Ioana Cotar,Mariana Carmen Chifiriuc,Alina Maria Holban,Otilia Banu
Biointerface Research in Applied Chemistry , 2012,
Abstract: Staphylococcus aureus is an extremely versatile pathogen responsible for a large spectrum of human diseases, ranging from skin infections and food poisoning to life-threatening nosocomial infections. S. aureus pathogenicity is a complex process involving a diverse array of virulence factors that are coordinately expressed during different stages of infection by a network of virulence regulators. The accessory gene regulator (agr) is one of these virulence regulators, being a quorum-sensing system activated by a bacterial-density-sensing peptide (autoinducing peptide - AIP). Different S. aureus strains produce AIPs with distinct structures, and strains can be grouped on this basis since they will activate the agr response of strains within the same group and inhibit the agr response of strains from different groups by competitive inhibition. The aim of this study was to investigate the potential associations between each agr group and a certain type of clinical sample by studying 88 S. aureus strains isolated from different clinical specimens from patients admitted in the Emergency Institute for Cardiovascular Diseases, Bucharest. A multiplex PCR was used to determine the agr groups among analyzed strains. The obtained results showed that agr III was the most prevalent group among the tested strains. The agr I was associated with strains isolated from blood cultures, whereas agr III prevailed among strains isolated from respiratory tract secretions. Although the obtained results do not allow us to establish a direct relationship between the agr group and type of S. aureus infection, but we can speculate that the preferential association between certain agr alleles and virulence factors may favour a more efficient activation of the virulence potential.
Combining Biofilm-Controlling Compounds and Antibiotics as a Promising New Way to Control Biofilm Infections
Andréia Bergamo Estrela,Wolf-Rainer Abraham
Pharmaceuticals , 2010, DOI: 10.3390/ph3051374
Abstract: Many bacteria grow on surfaces forming biofilms. In this structure, they are well protected and often high dosages of antibiotics cannot clear infectious biofilms. The formation and stabilization of biofilms are mediated by diffusible autoinducers (e.g. N-acyl homoserine lactones, small peptides, furanosyl borate diester). Metabolites interfering with this process have been identified in plants, animals and microbes, and synthetic analogues are known. Additionally, this seems to be not the only way to control biofilms. Enzymes capable of cleaving essential components of the biofilm matrix, e.g. polysaccharides or extracellular DNA, and thus weakening the biofilm architecture have been identified. Bacteria also have mechanisms to dissolve their biofilms and return to planktonic lifestyle. Only a few compounds responsible for the signalling of these processes are known, but they may open a completely novel line of biofilm control. All these approaches lead to the destruction of the biofilm but not the killing of the pathogens. Therefore, a combination of biofilm-destroying compounds and antibiotics to handle biofilm infections is proposed. In this article, different approaches to combine biofilm-controlling compounds and antibiotics to fight biofilm infections are discussed, as well as the balance between biofilm formation and virulence.
Functions and regulation of quorum-sensing in Agrobacterium tumefaciens
Julien Lang,Denis Faure
Frontiers in Plant Science , 2014, DOI: 10.3389/fpls.2014.00014
Abstract: In Agrobacterium tumefaciens, horizontal transfer and vegetative replication of oncogenic Ti plasmids involve a cell-to-cell communication process called quorum-sensing (QS). The determinants of the QS-system belong to the LuxR/LuxI class. The LuxI-like protein TraI synthesizes N-acyl-homoserine lactone molecules which act as diffusible QS-signals. Beyond a threshold concentration, these molecules bind and activate the LuxR-like transcriptional regulator TraR, thereby initiating the QS-regulatory pathway. For the last 20 years, A. tumefaciens has stood as a prominent model in the understanding of the LuxR/LuxI type of QS systems. A number of studies also unveiled features which are unique to A. tumefaciens QS, some of them being directly related to the phytopathogenic lifestyle of the bacteria. In this review, we will present the current knowledge of QS in A. tumefaciens at both the genetic and molecular levels. We will also describe how interactions with plant host modulate the QS pathway of A. tumefaciens, and discuss what could be the advantages for the agrobacteria to use such a tightly regulated QS-system to disseminate the Ti plasmids.
Biological Activity of Volatiles from Marine and Terrestrial Bacteria
Stefan Schulz,Jeroen S. Dickschat,Brigitte Kunze,Irene Wagner-Dobler,Randi Diestel,Florenz Sasse
Marine Drugs , 2010, DOI: 10.3390/md8122976
Abstract: The antiproliferative activity of 52 volatile compounds released from bacteria was investigated in agar diffusion assays against medically important microorganisms and mouse fibroblasts. Furthermore, the activity of these compounds to interfere with the quorum-sensing-systems was tested with two different reporter strains. While some of the compounds specific to certain bacteria showed some activity in the antiproliferative assay, the compounds common to many bacteria were mostly inactive. In contrast, some of these compounds were active in the quorum-sensing-tests. γ-Lactones showed a broad reactivity, while pyrazines seem to have only low intrinsic activity. A general discussion on the ecological importance of these findings is given.
A Lux-like Quorum Sensing System in the Extreme Acidophile Acidithiobacillus ferrooxidans
RIVAS,MARIELLA; SEEGER,MICHAEL; HOLMES,DAVID S; JEDLICKI,EUGENIA;
Biological Research , 2005, DOI: 10.4067/S0716-97602005000200018
Abstract: the genome of the acidophilic, proteobacterium acidithiobacillus ferrooxidans, contains linked but divergently oriented genes, termed afei and afer, whose predicted protein products are significantly similar to the luxi and luxr families of proteins. a possible promoter and lux box are predicted upstream of afei. a cloned copy of afei, expressed in e. coli, encodes an enzyme that catalyzes the production of a diffusible compound identified by gas chromatography and mass spectrometry as an unsubstituted n-acyl homoserine lactone (ahl) of chain length c14. this ahl can be detected by a reporter strain of sinorhizobium meliloti rm41 suggesting that it is biologically active. the reporter strain also responds to extracts of the supernatant of a. ferrooxidans grown to early stationary phase in sulfur medium indicating that a diffusible ahl is produced by this microorganism. semi-quantitative rt-pcr experiments indicate that afei and afer are expressed maximally in early stationary phase and are more expressed when a. ferrooxidans is grown in sulfur- rather than iron-containing medium. given the predicted amino acid sequence and functional properties of afei and afer it is proposed that a. ferrooxidans has a quorum sensing system similar to the luxi-luxr paradigm.
Molecular characterization of virulence patterns in Pseudomonas aeruginosa strains isolated from respiratory and wound samples
Ani Ioana Cotar,Mariana Carmen Chifiriuc,Otilia Banu,Veronica Lazar
Biointerface Research in Applied Chemistry , 2013,
Abstract: The versatile human opportunistic pathogen, Pseudomonas aeruginosa is responsible for a large spectrum of infections due to its impressive array of virulence factors, whose coordinated expression is regulated by many virulence regulatory systems. Among them an important role is playing by two well interrelated (las and rhl) quorum-sensing (QS) systems. The mutations occurred in either of the QS genes are associated with low virulence and a poor infective potential. The purpose of this study was to perform the molecular characterization of QS systems and of eleven extracellular virulence factors, whose expression is regulated by QS systems, in 49 P. aeruginosa strains isolated from respiratory tract secretions and wound secretions samples from patients with cardiovascular surgery associated infections in order to establish the correlations between certain virulence patterns and the clinical origin of bacterial strains. The results of this study showed that all analyzed strains possess QS genes, and five of eleven virulence genes regulated by QS systems. The protease IV and ExoU genes were specifically associated with the origin of the clinical strains, proving that these virulence genes could represent useful diagnosis markers for differentiating clinical P. aeruginosa strains.
A Lux-like Quorum Sensing System in the Extreme Acidophile Acidithiobacillus ferrooxidans
MARIELLA RIVAS,MICHAEL SEEGER,DAVID S HOLMES,EUGENIA JEDLICKI
Biological Research , 2005,
Abstract: The genome of the acidophilic, proteobacterium Acidithiobacillus ferrooxidans, contains linked but divergently oriented genes, termed afeI and afeR, whose predicted protein products are significantly similar to the LuxI and LuxR families of proteins. A possible promoter and Lux box are predicted upstream of afeI. A cloned copy of afeI, expressed in E. coli, encodes an enzyme that catalyzes the production of a diffusible compound identified by gas chromatography and mass spectrometry as an unsubstituted N-acyl homoserine lactone (AHL) of chain length C14. This AHL can be detected by a reporter strain of Sinorhizobium meliloti Rm41 suggesting that it is biologically active. The reporter strain also responds to extracts of the supernatant of A. ferrooxidans grown to early stationary phase in sulfur medium indicating that a diffusible AHL is produced by this microorganism. Semi-quantitative RT-PCR experiments indicate that afeI and afeR are expressed maximally in early stationary phase and are more expressed when A. ferrooxidans is grown in sulfur- rather than iron-containing medium. Given the predicted amino acid sequence and functional properties of AfeI and AfeR it is proposed that A. ferrooxidans has a quorum sensing system similar to the LuxI-LuxR paradigm.
Page 1 /6218
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.