The Mechanism of Sensory Transduction and Chemotaxis in Bacteria PDF Download
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Author: Myles Grossman
Publisher:
ISBN:
Category : Bacteria
Languages : en
Pages : 76
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Book Description
Author: Myles Grossman
Publisher:
ISBN:
Category : Bacteria
Languages : en
Pages : 76
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Book Description
Author: Bozzano G Luisa
Publisher: Academic Press
ISBN: 0323139124
Category : Science
Languages : en
Pages : 480
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Book Description
An explosion of information has occurred over the past few years in the field of signal transduction. As information form prokaryotes and eukaryotes has accumulated, it has become evident that diverse sensory systems share common mechanistic themes. This volume reviews our the current knowledge of molecular mechanisms for sensory transduction in a variety of microbial systems, as well as elegant work done in nematodes and Drosophila. Signal Transduction is intended for both researchers studying microbial systems and investigators and students of signal transduction in more complex organisms, who can learn from the paradigms and mechanisms conserved between prokaryotes and eukaryotes.
Author: Society for General Microbiology. Symposium
Publisher: Cambridge University Press
ISBN: 9780521403139
Category : Science
Languages : en
Pages : 424
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Book Description
The tendency of a living organism to move to a more favourable environment is a natural but complex reaction, involving the integration of sometimes conflicting environmental stimuli as well as a coordinated mechanical response. The response of motile, single cell organisms to environmental stimuli provides a useful model for understanding first of all how the environment is monitored and sensed, and secondly how this information is processed to result in an integrated and coordinated response. The volume looks at a large number of well-studied examples of the chemotactic response, in prokaryotes and eukaryotes, and casts new light on how cells process information and react to their environment. This fundamental response is of great importance in understanding one of the characteristic features of living organisms.
Author: G. L. Hazelbauer
Publisher: Chapman & Hall
ISBN:
Category : Medical
Languages : en
Pages : 360
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Book Description
Author: Michael Eisenbach
Publisher: Amsterdam ; New York : Elsevier Science Publishers ; New York, NY, USA : Sole distributors for the USA and Canada, Elsevier Science Publishing Company
ISBN:
Category : Medical
Languages : en
Pages : 322
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Book Description
Author: Mattias Collin
Publisher: Karger Medical and Scientific Publishers
ISBN: 3805591322
Category : Medical
Languages : en
Pages : 239
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Book Description
Over the last fifteen years it has become increasingly obvious that bacteria are not as simple and solitary as once believed. Rather, an accumulating body of work shows that bacteria are highly complicated and social organisms, constantly sensing their surroundings and altering both their environments and behaviors to ensure survival. Direct communication between bacteria turns out to be quite common, as are coordinated intra- and interspecies responses that include the formation of highly sophisticated microbial communities. In fact, threats to bacterial survival from assaults ranging from nutrient deprivation and oxygen depletion tothe defenses of eukaryotic hostsare all managed through the integration of a dizzying array of complex sensory and communication systems with the appropriate bacterial behaviors. This volume provides an update of the current knowledgeinthe expanding field ofbacterial sensing and signaling, highlighting its most important and interesting aspects. In twelve state-of-the-art articles, respected international experts address topics such as quorum sensing and secondary messengers, chemotaxis and magnetoaerotaxis, two-component phosphotransferase systems, bacterial virulence mechanisms, thermoregulation, and more. The final chapter represents a unique description of the tools available to manipulate many of the sensing and signaling systems described in this volume. Bacterial Sensing and Signaling is recommended reading for students, scientists and clinicians with interests in microbiology, immunology, ecology, biotechnology and a range of other disciplines.
Author: Nattakan Sukomon
Publisher:
ISBN:
Category :
Languages : en
Pages : 482
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Book Description
Bacteria utilize two-component systems to respond and adapt to changes in their environments. Central to the systems are modular receptors that comprise various functional domains to detect those changes and relay signals to effector domains. HAMP (Histidine kinases, Adenylate cyclases, Methyl accepting proteins and Phosphatases) and PAS (Per-Arnt-Sim) are two of the most common domains that couple various effectors to regulate a wide range of cellular activities. HAMP domains are signal relay modules that connects input and output domains. The HAMP domain from the E. coli serine receptor Tsr has been extensively studied by using genetic techniques, which leads to a model of HAMP biphasic stability that explains the behaviors of Tsr mutant receptors. However, limited biophysical data on the Tsr HAMP are available due to the instability of the domain. In order to provide stability to the Tsr HAMP, a chimera containing Tsr spliced into the poly-HAMP domains from Pseudomonas aeruginosa Aer2 (PaAer2) was created. Within the chimera, the Tsr HAMP maintains its characteristic four-helix coiled-coil structure with the distinctively lowered melting temperature compared to the PaAer2. This chimera was used to study three well-characterized HAMP mutational phenotypes differentiated by flagella-rotation patterns and CheA kinase activities: functional counterclockwise flagella rotation [CCW(A), kinase off], functional clockwise flagella rotation (CW, kinase on), and lesion-induced counterclockwise rotation [CCW(B), kinase off]. The stabilities and structural dynamics of the three phenotypes conform to the biphasic model. The transitions between functional on and off states are mediated by helix rotations and scissor-type movements. In the lesion-induced kinase off, the AS1 helices dissociate from the bundle while the AS2 helices form a two-helix colied coil. Overall, this study provides insights into relationships between HAMP conformational behaviors and their corresponding functional outputs. PAS domains are sensor motifs that are critical in signal transductions of prokaryotic and eukaryotic sensory proteins including chemoreceptors. Vibrio cholerae Aer2 (VcAer2), a PaAer2 homolog, has been shown to mediate responses to oxygen through the heme-binding PAS domains. Substitution of the conserved Trp 276 in the PAS2 domain to Leu abolished the O2-stabilizing ability, which corroborates its O2-ligating role. The crystal structure of the VcAer2 W276L is highly similar to the CN-bound PAS domain from PaAer2, suggesting the structure of the W276L mutant might represent the ligand-binding state. VcAer2 can serve as a promising alternative to E. coli Aer or PaAer2 for investigating PAS-mediated chemotaxis.
Author: Michael Eisenbach
Publisher: World Scientific Publishing Company
ISBN: 1911299018
Category : Science
Languages : en
Pages : 516
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Book Description
With contribution from Joseph W Lengeler (University of Osnabr
Author: J. P. Armitage
Publisher: Cambridge University Press
ISBN: 9780521403139
Category : Science
Languages : en
Pages : 420
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Book Description
Until recently the description of environmentally directed behavior had been at the phenomenological level. However, over the past decade, the mechanisms of movement, environmental sensing, and sensory transduction are being understood at the molecular level in both prokaryotic and eukaryotic single-celled organisms. This book covers the entire range of single-cell sensory transduction, from theories of gradient perception in prokaryotic and eukaryotic cells to the detailed molecular structure and function of sensory receptors, their respective secondary messengers, and the mechanisms of movement. The authors have also attempted to put the complex mechanisms of sensory transduction into the context of the organisms in their natural environment.
Author: Wei Yuan
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Abstract The two-component based chemotaxis signal transduction system allows flagellated bacteria to sense their surrounding chemical environment and move towards more favorable conditions. The attractant signals can be sensed by transmembrane chemoreceptors, and then transmitted to the histidine kinase CheA. Once activated, CheA interacts with the response regulator CheY through phosphorelay, which causes a change in the rotation of the flagella. The direction of flagella rotation determines whether a cell swims straight or just tumbles. Cells also need adaptation to respond to a change in chemical concentrations, and return to their prestimulated level. Adaptation in the B. subtilis chemotaxis system is achieved by three coordinated systems: the methylation system, the CheC/CheD/CheY-p system and the CheV system. CheD, the previously identified receptor deamidase, was shown to be critical to the ability of B. subtilis to perform chemotaxis and is the main focus of this study. This study started from characterization of the enzymatic mechanism of CheD. Results showed that CheD deamidase uses a cysteine hydrolase mechanism. The catalytic triad consisting of Cys33-His50-Thr27, and Ser27 is essential for receptor recognition and binding. In addition, in this study CheC was found to inhibit CheD0́9s deamidase activity. Through mutant screening, Phe102 on CheD was found to be the essential site to interact with CheC. Furthermore, the CheD/CheC interaction is necessary for the robust chemotaxis in vivo as demonstrated by the cheD (F102E) mutant, which lacks the ability to swim on swarm plates. Despite its deamidase activity, we hypothesized that CheD0́9s main role is its involvement in the CheD-CheC-CheY-p negative feedback pathway during adaptation. In particular, CheD is likely to help stabilize the transient kinase-activating state through binding to receptors. When CheY-p level is increased, CheC-CheY-p complex may attract CheD away from receptors. In this study, CheC-CheD binding kinetics with CheY or CheYp presence was successfully obtained by a series of SPR experiments. The increased affinity of CheD for CheC in presence of CheYp but not CheY makes likely the hypothesis that CheC-CheD-CheY interact as part of a negative feedback pathway during adaptation. Last, the interaction between CheD and chemoreceptor McpC was studied in order to better understand the role of CheD in adaptation. Results showed that Q304 and Q305 on McpC are essential to recruit CheD. Additionally, the reduced levels of CheD in mcpC (Q304A) or (Q305A) mutants suggested that the dynamic interaction between CheD and receptors is vital to maintain the normal CheD level. These findings suggest more complicated roles of CheD than its previously identified function as a receptor deamidase, and will lead to a clearer picture of the coordination of the three adaptational systems in the B. subtilis chemotactic sensory transduction system.
