| Mathematical modeling and experimental validation of chemotaxis under controlled gradients of methyl-aspartate in Escherichia coli. | |
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MedLine Citation:
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PMID: 20485750 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Escherichia coli has evolved an intracellular pathway to regulate its motion termed as chemotaxis so as to move towards a favorable environment such as regions with higher concentration of nutrients. Chemotaxis is a response to temporal and spatial variation of extracellular ligand concentration and randomness in motion induced by collisions with solvent molecules. Previous studies have reported average drift velocities for a given gradient and do not measure drift velocities as a function of time and space. To address this issue, a novel experimental technique was developed to quantify the motion of E. coli cells to varying concentrations and gradients of methyl-aspartate so as to capture the spatial and temporal variation of the drift velocity. A two-state receptor model accounting for the intracellular signaling pathway predicted the experimentally observed increase in drift velocity with gradient and the subsequent adaptation. Our study revealed that the rotational diffusivity induced by the extracellular environment is crucial in determining the drift velocity of E. coli. The model predictions matched with experimental observations only when the response of the intracellular pathway was highly ultra-sensitive to overcome the extracellular randomness. The parametric sensitivity of the pathway indicated that the dissociation constant for the binding of the ligand and the rate constants of the methylation/demethylation of the receptor are key to predict the performance of the chemotactic behavior. The study also indicates a possible role of oxygen in the chemotaxis response and that the response to a ligand may have to account for effects of oxygen. |
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Authors:
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Rajitha R Vuppula; Mahesh S Tirumkudulu; Kareenhalli V Venkatesh |
Publication Detail:
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Type: Journal Article Date: 2010-03-18 |
Journal Detail:
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Title: Molecular bioSystems Volume: 6 ISSN: 1742-2051 ISO Abbreviation: Mol Biosyst Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-05-20 Completed Date: 2010-08-30 Revised Date: 2011-05-16 |
Medline Journal Info:
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Nlm Unique ID: 101251620 Medline TA: Mol Biosyst Country: England |
Other Details:
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Languages: eng Pagination: 1082-92 Citation Subset: IM |
Affiliation:
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Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076. rajitha@iitb.ac.in |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological
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physiology Algorithms Chemotaxis / physiology* Escherichia coli / physiology* Kinetics Models, Biological* N-Methylaspartate / metabolism* Oxygen / metabolism Signal Transduction* Time Factors |
| Chemical | |
Reg. No./Substance:
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6384-92-5/N-Methylaspartate; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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