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Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time
Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity v(d) is a constant in an exponential at...
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2010
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851563/ https://www.ncbi.nlm.nih.gov/pubmed/20386737 http://dx.doi.org/10.1371/journal.pcbi.1000735 |
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author | Jiang, Lili Ouyang, Qi Tu, Yuhai |
author_facet | Jiang, Lili Ouyang, Qi Tu, Yuhai |
author_sort | Jiang, Lili |
collection | PubMed |
description | Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity v(d) is a constant in an exponential attractant concentration gradient [L]∝exp(Gx). v(d) depends linearly on the exponential gradient G before it saturates when G is larger than a critical value G(C). We find that G(C) is determined by the intracellular adaptation rate k(R) with a simple scaling law: [Image: see text]. The linear dependence of v(d) on G = d(ln[L])/dx directly demonstrates E. coli's ability in sensing the derivative of the logarithmic attractant concentration. The existence of the limiting gradient G(C) and its scaling with k(R) are explained by the underlying intracellular adaptation dynamics and the flagellar motor response characteristics. For individual cells, we find that the overall average run length in an exponential gradient is longer than that in a homogeneous environment, which is caused by the constant kinase activity shift (decrease). The forward runs (up the gradient) are longer than the backward runs, as expected; and depending on the exact gradient, the (shorter) backward runs can be comparable to runs in a spatially homogeneous environment, consistent with previous experiments. In (spatial) ligand gradients that also vary in time, the chemotaxis motion is damped as the frequency ω of the time-varying spatial gradient becomes faster than a critical value ω(c), which is controlled by the cell's chemotaxis adaptation rate k(R). Finally, our model, with no adjustable parameters, agrees quantitatively with the classical capillary assay experiments where the attractant concentration changes both in space and time. Our model can thus be used to study E. coli chemotaxis behavior in arbitrary spatiotemporally varying environments. Further experiments are suggested to test some of the model predictions. |
format | Text |
id | pubmed-2851563 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-28515632010-04-12 Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time Jiang, Lili Ouyang, Qi Tu, Yuhai PLoS Comput Biol Research Article Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity v(d) is a constant in an exponential attractant concentration gradient [L]∝exp(Gx). v(d) depends linearly on the exponential gradient G before it saturates when G is larger than a critical value G(C). We find that G(C) is determined by the intracellular adaptation rate k(R) with a simple scaling law: [Image: see text]. The linear dependence of v(d) on G = d(ln[L])/dx directly demonstrates E. coli's ability in sensing the derivative of the logarithmic attractant concentration. The existence of the limiting gradient G(C) and its scaling with k(R) are explained by the underlying intracellular adaptation dynamics and the flagellar motor response characteristics. For individual cells, we find that the overall average run length in an exponential gradient is longer than that in a homogeneous environment, which is caused by the constant kinase activity shift (decrease). The forward runs (up the gradient) are longer than the backward runs, as expected; and depending on the exact gradient, the (shorter) backward runs can be comparable to runs in a spatially homogeneous environment, consistent with previous experiments. In (spatial) ligand gradients that also vary in time, the chemotaxis motion is damped as the frequency ω of the time-varying spatial gradient becomes faster than a critical value ω(c), which is controlled by the cell's chemotaxis adaptation rate k(R). Finally, our model, with no adjustable parameters, agrees quantitatively with the classical capillary assay experiments where the attractant concentration changes both in space and time. Our model can thus be used to study E. coli chemotaxis behavior in arbitrary spatiotemporally varying environments. Further experiments are suggested to test some of the model predictions. Public Library of Science 2010-04-08 /pmc/articles/PMC2851563/ /pubmed/20386737 http://dx.doi.org/10.1371/journal.pcbi.1000735 Text en Jiang et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Jiang, Lili Ouyang, Qi Tu, Yuhai Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title | Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title_full | Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title_fullStr | Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title_full_unstemmed | Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title_short | Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time |
title_sort | quantitative modeling of escherichia coli chemotactic motion in environments varying in space and time |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851563/ https://www.ncbi.nlm.nih.gov/pubmed/20386737 http://dx.doi.org/10.1371/journal.pcbi.1000735 |
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