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Chemophoresis as a driving force for intracellular organization: Theory and application to plasmid partitioning

View Article: PubMed Central - PubMed

ABSTRACT

Biological units such as macromolecules, organelles, and cells are directed to a proper location by gradients of chemicals. We consider a macroscopic element with surface binding sites where chemical adsorption reactions can occur and show that a thermodynamic force generated by chemical gradients acts on the element. By assuming local equilibrium and adopting the grand potential used in thermodynamics, we derive a formula for the “chemophoresis” force, which depends on chemical potential gradients and the Langmuir isotherm. The conditions under which the formula is applicable are shown to occur in intracellular reactions. Further, the role of the chemophoresis in the partitioning of bacterial chromosomal loci/plasmids during cell division is discussed. By performing numerical simulations, we demonstrate that the chemophoresis force can contribute to the regular positioning of plasmids observed in experiments.

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Dynamics and distribution along the long cell axis of u(r) and plasmids. We show the cases of N = 1 and 2. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2. Obtained from simulations of Eqs. (8) and (9) under the Neumann boundary condition, with the parameter values a = 1, b = 10, c = 0.1, k = 1, D = 0.5, K = 0.5, n = 1, γ = 1000, L = 10, and kBT = 1.
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f2-7_77: Dynamics and distribution along the long cell axis of u(r) and plasmids. We show the cases of N = 1 and 2. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2. Obtained from simulations of Eqs. (8) and (9) under the Neumann boundary condition, with the parameter values a = 1, b = 10, c = 0.1, k = 1, D = 0.5, K = 0.5, n = 1, γ = 1000, L = 10, and kBT = 1.

Mentions: First, we examine the case of N = 1 and 2 to examine how two replicated plasmids are separated into daughter cells. Figure 2 shows the dynamics and distribution of u(r) and plasmid(s) along the long cell axis for the two N values. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2 (Fig. 2). These results are consistent with earlier reports on plasmid positioning during cell division20,21.


Chemophoresis as a driving force for intracellular organization: Theory and application to plasmid partitioning
Dynamics and distribution along the long cell axis of u(r) and plasmids. We show the cases of N = 1 and 2. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2. Obtained from simulations of Eqs. (8) and (9) under the Neumann boundary condition, with the parameter values a = 1, b = 10, c = 0.1, k = 1, D = 0.5, K = 0.5, n = 1, γ = 1000, L = 10, and kBT = 1.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036777&req=5

f2-7_77: Dynamics and distribution along the long cell axis of u(r) and plasmids. We show the cases of N = 1 and 2. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2. Obtained from simulations of Eqs. (8) and (9) under the Neumann boundary condition, with the parameter values a = 1, b = 10, c = 0.1, k = 1, D = 0.5, K = 0.5, n = 1, γ = 1000, L = 10, and kBT = 1.
Mentions: First, we examine the case of N = 1 and 2 to examine how two replicated plasmids are separated into daughter cells. Figure 2 shows the dynamics and distribution of u(r) and plasmid(s) along the long cell axis for the two N values. A plasmid is localized at the center of the cell for N = 1 whereas two plasmids are positioned approximately at distances of one-quarter and three-quarters of the cell axis for N = 2 (Fig. 2). These results are consistent with earlier reports on plasmid positioning during cell division20,21.

View Article: PubMed Central - PubMed

ABSTRACT

Biological units such as macromolecules, organelles, and cells are directed to a proper location by gradients of chemicals. We consider a macroscopic element with surface binding sites where chemical adsorption reactions can occur and show that a thermodynamic force generated by chemical gradients acts on the element. By assuming local equilibrium and adopting the grand potential used in thermodynamics, we derive a formula for the “chemophoresis” force, which depends on chemical potential gradients and the Langmuir isotherm. The conditions under which the formula is applicable are shown to occur in intracellular reactions. Further, the role of the chemophoresis in the partitioning of bacterial chromosomal loci/plasmids during cell division is discussed. By performing numerical simulations, we demonstrate that the chemophoresis force can contribute to the regular positioning of plasmids observed in experiments.

No MeSH data available.


Related in: MedlinePlus