The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
NED SCOTT WINGREEN - One of the best experts on this subject based on the ideXlab platform.
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Fundamental constraints on the abundances of Chemotaxis proteins.
Biophysical Journal, 2015Co-Authors: Anne-florence Bitbol, NED SCOTT WINGREENAbstract:Flagellated bacteria, such as Escherichia coli, perform directed motion in gradients of concentration of attractants and repellents in a process called Chemotaxis. The E. coli Chemotaxis signaling pathway is a model for signal transduction, but it has unique features. We demonstrate that the need for fast signaling necessitates high abundances of the proteins involved in this pathway. We show that further constraints on the abundances of Chemotaxis proteins arise from the requirements of self-assembly both of flagellar motors and of chemoreceptor arrays. All these constraints are specific to Chemotaxis, and published data confirm that Chemotaxis proteins tend to be more highly expressed than their homologs in other pathways. Employing a Chemotaxis pathway model, we show that the gain of the pathway at the level of the response regulator CheY increases with overall Chemotaxis protein abundances. This may explain why, at least in one E. coli strain, the abundance of all Chemotaxis proteins is higher in media with lower nutrient content. We also demonstrate that the E. coli Chemotaxis pathway is particularly robust to abundance variations of the motor protein FliM.
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responding to chemical gradients bacterial Chemotaxis
Current Opinion in Cell Biology, 2012Co-Authors: Victor Sourjik, NED SCOTT WINGREENAbstract:Chemotaxis allows bacteria to follow gradients of nutrients and other environmental stimuli. The bacterium Escherichia coli performs Chemotaxis via a run-and-tumble strategy in which sensitive temporal comparisons lead to a biased random walk, with longer runs in the preferred gradient direction. The Chemotaxis network of E. coli has developed over the years into one of the most thoroughly studied model systems for signal transduction and behavior, yielding general insights into such properties of cellular networks as signal amplification, signal integration, and robustness. Despite its relative simplicity, the operation of the E. coli Chemotaxis network is highly refined and evolutionarily optimized at many levels. For example, recent studies revealed that the network adjusts its signaling properties dependent on the extracellular environment, apparently to optimize Chemotaxis under particular conditions. The network can even utilize potentially detrimental stochastic fluctuations in protein levels and reaction rates to maximize the chemotactic performance of the population.
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Responding to chemical gradients: Bacterial Chemotaxis
Current Opinion in Cell Biology, 2012Co-Authors: Victor Sourjik, NED SCOTT WINGREENAbstract:Chemotaxis allows bacteria to follow gradients of nutrients and other environmental stimuli. The bacterium Escherichia coli performs Chemotaxis via a run-and-tumble strategy in which sensitive temporal comparisons lead to a biased random walk, with longer runs in the preferred gradient direction. The Chemotaxis network of E. coli has developed over the years into one of the most thoroughly studied model systems for signal transduction and behavior, yielding general insights into such properties of cellular networks as signal amplification, signal integration, and robustness. Despite its relative simplicity, the operation of the E. coli Chemotaxis network is highly refined and evolutionarily optimized at many levels. For example, recent studies revealed that the network adjusts its signaling properties dependent on the extracellular environment, apparently to optimize Chemotaxis under particular conditions. The network can even utilize potentially detrimental stochastic fluctuations in protein levels and reaction rates to maximize the chemotactic performance of the population. © 2011 Elsevier Ltd.
Gladys M. Alexandre - One of the best experts on this subject based on the ideXlab platform.
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Chemotaxis signaling systems in model beneficial plant–bacteria associations
Plant Molecular Biology, 2016Co-Authors: Birgit E. Scharf, Michael F. Hynes, Gladys M. AlexandreAbstract:Beneficial plant–microbe associations play critical roles in plant health. Bacterial Chemotaxis provides a competitive advantage to motile flagellated bacteria in colonization of plant root surfaces, which is a prerequisite for the establishment of beneficial associations. Chemotaxis signaling enables motile soil bacteria to sense and respond to gradients of chemical compounds released by plant roots. This process allows bacteria to actively swim towards plant roots and is thus critical for competitive root surface colonization. The complete genome sequences of several plant-associated bacterial species indicate the presence of multiple Chemotaxis systems and a large number of chemoreceptors. Further, most soil bacteria are motile and capable of Chemotaxis, and Chemotaxis-encoding genes are enriched in the bacteria found in the rhizosphere compared to the bulk soil. This review compares the architecture and diversity of Chemotaxis signaling systems in model beneficial plant-associated bacteria and discusses their relevance to the rhizosphere lifestyle. While it is unclear how controlling Chemotaxis via multiple parallel Chemotaxis systems provides a competitive advantage to certain bacterial species, the presence of a larger number of chemoreceptors is likely to contribute to the ability of motile bacteria to survive in the soil and to compete for root surface colonization.
Ruifu Zhang - One of the best experts on this subject based on the ideXlab platform.
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recognition of dominant attractants by key chemoreceptors mediates recruitment of plant growth promoting rhizobacteria
Environmental Microbiology, 2019Co-Authors: Haichao Feng, Nan Zhang, Ruixin Fu, Tino Krell, Wenbin Du, Jiahui Shao, Qirong Shen, Ruifu ZhangAbstract:: Chemotaxis to plant root exudates is supposed to be a prerequisite for efficient root colonization by rhizobacteria. This is a highly multifactorial process since root exudates are complex compound mixtures of which components are recognized by different chemoreceptors. Little information is available as to the key components in root exudates and their receptors that drive colonization related Chemotaxis. We present here the first global assessment of this issue using the plant growth-promoting rhizobacterium (PGPR) Bacillus velezensis SQR9 (formerly B. amyloliquefaciens). This strain efficiently colonizes cucumber roots, and here, we show that Chemotaxis to cucumber root exudates was essential in this process. We conducted Chemotaxis assays using cucumber root exudates at different concentrations, individual exudate components as well as recomposed exudates, taking into account their concentrations detected in root exudates. Results indicated that two key chemoreceptors, McpA and McpC, were essential for root exudate Chemotaxis and root colonization. Both receptors possess a broad ligand range and recognize most of the exudate key components identified (malic, fumaric, gluconic and glyceric acids, Lys, Ser, Ala and mannose). The remaining six chemoreceptors did not contribute to exudate Chemotaxis. This study provides novel insight into the evolution of the Chemotaxis system in rhizobacteria.
Victor Sourjik - One of the best experts on this subject based on the ideXlab platform.
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responding to chemical gradients bacterial Chemotaxis
Current Opinion in Cell Biology, 2012Co-Authors: Victor Sourjik, NED SCOTT WINGREENAbstract:Chemotaxis allows bacteria to follow gradients of nutrients and other environmental stimuli. The bacterium Escherichia coli performs Chemotaxis via a run-and-tumble strategy in which sensitive temporal comparisons lead to a biased random walk, with longer runs in the preferred gradient direction. The Chemotaxis network of E. coli has developed over the years into one of the most thoroughly studied model systems for signal transduction and behavior, yielding general insights into such properties of cellular networks as signal amplification, signal integration, and robustness. Despite its relative simplicity, the operation of the E. coli Chemotaxis network is highly refined and evolutionarily optimized at many levels. For example, recent studies revealed that the network adjusts its signaling properties dependent on the extracellular environment, apparently to optimize Chemotaxis under particular conditions. The network can even utilize potentially detrimental stochastic fluctuations in protein levels and reaction rates to maximize the chemotactic performance of the population.
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Responding to chemical gradients: Bacterial Chemotaxis
Current Opinion in Cell Biology, 2012Co-Authors: Victor Sourjik, NED SCOTT WINGREENAbstract:Chemotaxis allows bacteria to follow gradients of nutrients and other environmental stimuli. The bacterium Escherichia coli performs Chemotaxis via a run-and-tumble strategy in which sensitive temporal comparisons lead to a biased random walk, with longer runs in the preferred gradient direction. The Chemotaxis network of E. coli has developed over the years into one of the most thoroughly studied model systems for signal transduction and behavior, yielding general insights into such properties of cellular networks as signal amplification, signal integration, and robustness. Despite its relative simplicity, the operation of the E. coli Chemotaxis network is highly refined and evolutionarily optimized at many levels. For example, recent studies revealed that the network adjusts its signaling properties dependent on the extracellular environment, apparently to optimize Chemotaxis under particular conditions. The network can even utilize potentially detrimental stochastic fluctuations in protein levels and reaction rates to maximize the chemotactic performance of the population. © 2011 Elsevier Ltd.
Birgit E. Scharf - One of the best experts on this subject based on the ideXlab platform.
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Chemotaxis signaling systems in model beneficial plant–bacteria associations
Plant Molecular Biology, 2016Co-Authors: Birgit E. Scharf, Michael F. Hynes, Gladys M. AlexandreAbstract:Beneficial plant–microbe associations play critical roles in plant health. Bacterial Chemotaxis provides a competitive advantage to motile flagellated bacteria in colonization of plant root surfaces, which is a prerequisite for the establishment of beneficial associations. Chemotaxis signaling enables motile soil bacteria to sense and respond to gradients of chemical compounds released by plant roots. This process allows bacteria to actively swim towards plant roots and is thus critical for competitive root surface colonization. The complete genome sequences of several plant-associated bacterial species indicate the presence of multiple Chemotaxis systems and a large number of chemoreceptors. Further, most soil bacteria are motile and capable of Chemotaxis, and Chemotaxis-encoding genes are enriched in the bacteria found in the rhizosphere compared to the bulk soil. This review compares the architecture and diversity of Chemotaxis signaling systems in model beneficial plant-associated bacteria and discusses their relevance to the rhizosphere lifestyle. While it is unclear how controlling Chemotaxis via multiple parallel Chemotaxis systems provides a competitive advantage to certain bacterial species, the presence of a larger number of chemoreceptors is likely to contribute to the ability of motile bacteria to survive in the soil and to compete for root surface colonization.
