The Relation of Signal Transduction to the Sensitivity and Dynamic Range of Bacterial Chemotaxis

Namba, T.; Nishikawa, Masaru; Shibata, Tatsuo

doi:10.1016/j.bpj.2012.08.034

Cited by 11 publications

(52 citation statements)

References 45 publications

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“…where A is a normalization constant (just the same as in equation (15)), c 1,2 and N are parameters of the model used in [6]. Formally, these relations (15) It is taken that a = a 2 · 10 p .…”

Section: Basic Modelmentioning

confidence: 99%

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Analytical Approach for Calculating the Chemotaxis Sensitivity Function

Vasilev

2018

Ukr. J. Phys.

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We consider the chemotaxis problem for a one-dimensional system. To analyze the interaction of bacteria and an attractant, we use a modified Keller-Segel model, which accounts for the attractant absorption. To describe the system, we use the chemotaxis sensitivity function, which characterizes the nonuniformity of the bacteria distribution. In particular, we investigate how the chemotaxis sensitivity function depends on the concentration of an attractant at the boundary of the system. It is known that, in the system without absorption, the chemotaxis sensitivity function has a bell shape maximum. Here, we show that the attractant absorption and special boundary conditions for bacteria can cause the appearance of an additional maximum in the chemotaxis sensitivity function. The value of this maximum is determined by the intensity of absorption.K e y w o r d s: chemotaxis, attractant, bacteria, absorption.

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Section: Basic Modelmentioning

confidence: 99%

“…It is also notable that in the limiting case when r c << L we can rewrite the expression for the chemotaxis sensitivity function like this [6]:…”

Section: Introductionmentioning

confidence: 99%

Analytical Approach for Calculating the Chemotaxis Sensitivity Function

Vasilev

2018

Ukr. J. Phys.

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“…Here, E. coli exhibits a temporal increase of its tumbling rate for changing its swimming direction, termed adaptation, consequent to sudden decreases (increases) in the concentrations of a chemoattractant (chemorepellent). The chemotaxis of E. coli has also been extensively investigated experimentally and theoretically [22–32]. Recently, a theoretical study using a model of chemoreceptor biochemical kinetics derived the experimentally observed form of a function, which depends on the background chemical concentration relationship to the chemotaxis sensitivity; this function corresponds to f ( I ) in the present study.…”

Section: Discussionmentioning

confidence: 88%

“…Recently, a theoretical study using a model of chemoreceptor biochemical kinetics derived the experimentally observed form of a function, which depends on the background chemical concentration relationship to the chemotaxis sensitivity; this function corresponds to f ( I ) in the present study. [32]. …”

Section: Discussionmentioning

confidence: 99%

The Flux of Euglena gracilis Cells Depends on the Gradient of Light Intensity

et al. 2016

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We have quantified the photomovement behavior of a suspension of Euglena gracilis representing a behavioral response to a light gradient. Despite recent measurements of phototaxis and photophobicity, the details of macroscopic behavior of cell photomovements under conditions of light intensity gradients, which are critical to understand recent experiments on spatially localized bioconvection patterns, have not been fully understood. In this paper, the flux of cell number density under a light intensity gradient was measured by the following two experiments. In the first experiment, a capillary containing the cell suspension was illuminated with different light intensities in two regions. In the steady state, the differences of the cell numbers in the two regions normalized by the total number were proportional to the light difference, where the light intensity difference ranged from 0.5–2.0 μmol m−2 s−1. The proportional coefficient was positive (i.e., the bright region contained many microorganisms) when the mean light intensity was weak (1.25 μmol m−2 s−1), whereas it was negative when the mean intensity was strong (13.75 μmol m−2 s−1). In the second experiment, a shallow rectangular container of the suspension was illuminated with stepwise light intensities. The cell number density distribution exhibited a single peak at the position where the light intensity was about Ic ≃ 3.8 μmol m−2 s−1. These results suggest that the suspension of E. gracilis responded to the light gradient and that the favorable light intensity was Ic.

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“…From a theoretical point of view, our study provides a possible mechanism for implementing cellular chirality by using PCP and CSK polarity. In the biological system, chirality appears at various levels ranging from molecular [31] and cellular [32] to the tissue level [33].…”

Section: Discussionmentioning

confidence: 99%

Cytoskeleton polarity is essential in determining orientational order in basal bodies of multi-ciliated cells

Namba

Ishihara

2020

PLoS Comput Biol

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In multi-ciliated cells, directed and synchronous ciliary beating in the apical membrane occurs through appropriate configuration of basal bodies (BBs, roots of cilia). Although it has been experimentally shown that the position and orientation of BBs are coordinated by apical cytoskeletons (CSKs), such as microtubules (MTs), and planar cell polarity (PCP), the underlying mechanism for achieving the patterning of BBs is not yet understood. In this study, we propose that polarity in bundles of apical MTs play a crucial role in the patterning of BBs. First, the necessity of the polarity was discussed by theoretical consideration on the symmetry of the system.The existence of the polarity was investigated by measuring relative angles between the MTs and BBs using published experimental data. Next, a mathematical model for BB patterning was derived by combining the polarity and self-organizational ability of CSKs. In the model, BBs were treated as finite-size particles in the medium of CSKs and excluded volume effects between BBs and CSKs were taken into account. The model reproduces the various experimental observations, including normal and drug-treated phenotypes. Our model with polarity provides a coherent and testable mechanism for apical BB pattern formation. We have also discussed the implication of our study on cell chirality. Author SummarySynchronous and directed ciliary beating in trachea allows transport and ejection of virus and dust from the body. This ciliary function depends on the coordinated configuration of basal bodies (root of cilia) in apical cell membrane. However, the mechanism for their formation remains unknown. In this study, we show that the polarity in apical microtubule bundles plays a significant role in the organization of basal bodies. A mathematical model incorporating polarity has been formulated which provides a coherent explanation and is able to reproduce experimental observations. We have clarified both necessity ('why polarity is required for pattern formation') and sufficiency ('how polarity works for pattern formation') of cytoskeleton polarity for correct pattering of basal bodies with verification by experimental data. This model further leads us to a possible mechanism for cellular chirality.

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The Relation of Signal Transduction to the Sensitivity and Dynamic Range of Bacterial Chemotaxis

Cited by 11 publications

References 45 publications

Analytical Approach for Calculating the Chemotaxis Sensitivity Function

Analytical Approach for Calculating the Chemotaxis Sensitivity Function

The Flux of Euglena gracilis Cells Depends on the Gradient of Light Intensity

Cytoskeleton polarity is essential in determining orientational order in basal bodies of multi-ciliated cells

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