The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Bonnie L Bassler - One of the best experts on this subject based on the ideXlab platform.
-
Quorum sensing signal–response systems in Gram-Negative Bacteria
Nature Reviews Microbiology, 2016Co-Authors: Kai Papenfort, Bonnie L BasslerAbstract:Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-Negative Bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal–response systems combine to control collective behaviours in Gram-Negative Bacteria and we discuss the implications for host–microbial associations and antiBacterial therapy. Quorum sensing is used to control the behaviour of Bacterial communities. In this Review, Papenfort and Bassler highlight recent discoveries about quorum sensing in Gram-Negative Bacteria, such as novel autoinducers and signalling networks that promote communication that ranges from intra-species to inter-kingdom. Quorum sensing is a cell–cell communication process that enables Bacteria to obtain information about cell density and species composition of the vicinal community and adjust their gene expression profiles accordingly. Quorum sensing involves the production, release and detection of extracellular signalling molecules known as autoinducers. Group-wide detection of autoinducers enables Bacteria to collectively execute behaviours. Autoinducers are small molecules that control quorum sensing. In Gram-Negative Bacteria, autoinducers are often produced from S -adenosylmethionine (SAM). Autoinducers interact with specific receptors to elicit behaviours that are controlled by quorum sensing. Quorum sensing receptors are either membrane-bound histidine sensor kinases or cytoplasmic transcription factors. Autoinduction occurs when the detection of autoinducers induces the increased production of the same autoinducer molecule, forming a feed-forward regulatory loop. Other features, such as positive and negative feedback loops and small regulatory RNAs, optimize the integration of the autoinducer-encoded information and provide ideal quorum sensing dynamics. Signal integration is a process that takes place in most Gram-Negative Bacteria when several autoinducers and receptors work in parallel, or in series, to synchronize functions that are controlled by quorum sensing. Processes such as bioluminescence, the production of virulence factors and the formation of biofilms are controlled by quorum sensing. Quorum sensing shapes the composition of microbial communities. For example, Bacterial species in the human gut microbiota produce and respond to autoinducers. There is increasing evidence that quorum sensing controls key physiological processes in the gut and may affect the virulence programmes of invading pathogens. Host cells are also known to produce autoinducer mimics. Synthetic quorum sensing modulators are molecules that agonize or antagonize quorum sensing and they are being developed as anti-virulence medicines. Distinct from traditional antibiotics, quorum sensing modulators do not affect the growth of pathogenic Bacteria, but rather, disrupt their virulence programmes.
-
quorum sensing signal response systems in gram negative Bacteria
Nature Reviews Microbiology, 2016Co-Authors: Kai Papenfort, Bonnie L BasslerAbstract:Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-Negative Bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal-response systems combine to control collective behaviours in Gram-Negative Bacteria and we discuss the implications for host-microbial associations and antiBacterial therapy.
Kai Papenfort - One of the best experts on this subject based on the ideXlab platform.
-
Quorum sensing signal–response systems in Gram-Negative Bacteria
Nature Reviews Microbiology, 2016Co-Authors: Kai Papenfort, Bonnie L BasslerAbstract:Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-Negative Bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal–response systems combine to control collective behaviours in Gram-Negative Bacteria and we discuss the implications for host–microbial associations and antiBacterial therapy. Quorum sensing is used to control the behaviour of Bacterial communities. In this Review, Papenfort and Bassler highlight recent discoveries about quorum sensing in Gram-Negative Bacteria, such as novel autoinducers and signalling networks that promote communication that ranges from intra-species to inter-kingdom. Quorum sensing is a cell–cell communication process that enables Bacteria to obtain information about cell density and species composition of the vicinal community and adjust their gene expression profiles accordingly. Quorum sensing involves the production, release and detection of extracellular signalling molecules known as autoinducers. Group-wide detection of autoinducers enables Bacteria to collectively execute behaviours. Autoinducers are small molecules that control quorum sensing. In Gram-Negative Bacteria, autoinducers are often produced from S -adenosylmethionine (SAM). Autoinducers interact with specific receptors to elicit behaviours that are controlled by quorum sensing. Quorum sensing receptors are either membrane-bound histidine sensor kinases or cytoplasmic transcription factors. Autoinduction occurs when the detection of autoinducers induces the increased production of the same autoinducer molecule, forming a feed-forward regulatory loop. Other features, such as positive and negative feedback loops and small regulatory RNAs, optimize the integration of the autoinducer-encoded information and provide ideal quorum sensing dynamics. Signal integration is a process that takes place in most Gram-Negative Bacteria when several autoinducers and receptors work in parallel, or in series, to synchronize functions that are controlled by quorum sensing. Processes such as bioluminescence, the production of virulence factors and the formation of biofilms are controlled by quorum sensing. Quorum sensing shapes the composition of microbial communities. For example, Bacterial species in the human gut microbiota produce and respond to autoinducers. There is increasing evidence that quorum sensing controls key physiological processes in the gut and may affect the virulence programmes of invading pathogens. Host cells are also known to produce autoinducer mimics. Synthetic quorum sensing modulators are molecules that agonize or antagonize quorum sensing and they are being developed as anti-virulence medicines. Distinct from traditional antibiotics, quorum sensing modulators do not affect the growth of pathogenic Bacteria, but rather, disrupt their virulence programmes.
-
quorum sensing signal response systems in gram negative Bacteria
Nature Reviews Microbiology, 2016Co-Authors: Kai Papenfort, Bonnie L BasslerAbstract:Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-Negative Bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal-response systems combine to control collective behaviours in Gram-Negative Bacteria and we discuss the implications for host-microbial associations and antiBacterial therapy.
Paul B. Savage - One of the best experts on this subject based on the ideXlab platform.
-
Multidrug-resistant Bacteria: overcoming antibiotic permeability barriers of Gram-Negative Bacteria.
Annals of medicine, 2001Co-Authors: Paul B. SavageAbstract:Because of the permeability barrier provided by the outer membrane (OM), Gram-Negative Bacteria are inherently resistant to many hydrophobic antibiotics. This resistance limits the arsenal of antibiotics that are effective in treating Gram-Negative Bacterial infections. Compounding this problem, strains of Gram-Negative Bacteria have emerged that display specific resistance mechanisms for effective antibiotics. As a means of expanding the arsenal of effective antibiotics for Gram-Negative Bacteria, compounds that permeabilize the OM to hydrophobic substances have been developed. These compounds are typically cationic, amphiphilic molecules that can be prepared from peptides or steroids. Effective OM permeabilizers sensitize Gram-Negative Bacteria to hydrophobic antibiotics, including erythromycin, fusidic acid, novobiocin and rifampin. These antibiotics are generally not useful in treating Gram-Negative Bacterial infections because they traverse the OM ineffectively. The use of OM permeabilizers, in combi...
-
Incremental Conversion of Outer-Membrane Permeabilizers into Potent Antibiotics for Gram-Negative Bacteria
Journal of the American Chemical Society, 1999Co-Authors: Loren P. Budge, Collin D. Driscoll, Barry M. Willardson, Glenn W. Allman, Paul B. SavageAbstract:Cholic acid derivatives appended with amine groups have been prepared for use as permeabilizers of the outer membranes of Gram-Negative Bacteria. These compounds interact synergistically with antibiotics such as erythromycin and novobiocin to inhibit growth of Gram-Negative Bacteria. When a hydrophobic chain is included on the permeabilizers, they can be converted into potent antibiotics. The role of the hydrophobic chain is to facilitate self-promoted transport of the cholic acid derivatives across the outer membrane of Gram-Negative Bacteria. These compounds share activities found with polymyxin B and derivatives.
Michael V. Martin - One of the best experts on this subject based on the ideXlab platform.
-
The incidence of oral Gram-Negative Bacteria in patients with Parkinson's disease
European journal of internal medicine, 2003Co-Authors: Margot Gosney, Shuja Punekar, Jeremy R. Playfer, Patricia K. Bilsborrow, Michael V. MartinAbstract:Background: Parkinson's disease is a common neurodegenerative disorder that affects an increasing number of older people every year. Dysphagia is not only a common feature, but one that results in poor nutrition and an increased risk of bronchopneumonia. Previous work has suggested that the oral flora is altered in patients with oral pathology. Methods: Fifty patients were assessed to quantify the incidence of oral Gram-Negative Bacteria. Results: Sixteen of the patients with Parkinson's disease were found to have six different Gram-Negative bacilli in their oral cavities. The 20 different Gram-Negative Bacteria present were Escherichia coli (n=7), Klebsiella spp. (n=3), Kluyvera spp. (n=3), Serratia spp. (n=3), Proteus spp. (n=2) and Enterobacter spp. (n=2). We found that the oral cavity of 16 (32%) of the patients with Parkinson's disease was abnormally colonised with Gram-Negative Bacteria and that Gram-Negative Bacteria were more likely to occur in those patients in whom oromuscular dysfunction was present (88% vs. 21%; p
Mingshu Wang - One of the best experts on this subject based on the ideXlab platform.
-
Polysaccharide export outer membrane proteins in Gram-Negative Bacteria.
Future microbiology, 2013Co-Authors: Biao Yuan, Anchun Cheng, Mingshu WangAbstract:Polysaccharide export outer membrane proteins of Gram-Negative Bacteria are involved in the export of polysaccharides across the outer membrane. The mechanisms of polysaccharide export across the outer membrane in Gram-Negative Bacteria are not yet completely clear. However, the mechanisms of polysaccharide assembly in Escherichia coli have been intensively investigated. Here, we mainly review the current understanding of the assembly mechanisms of group 1 capsular polysaccharide, group 2 capsular polysaccharide and lipopolysaccharide of E. coli, and the current structures and interactions of some polysaccharide export outer membrane proteins with other proteins involved in polysaccharide export in Gram-Negative Bacteria. In addition, LptD may be targeted by peptidomimetic antibiotics in Gram-Negative Bacteria. We also give insights into the directions of future research regarding the mechanisms of polysaccharide export.
