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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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Distribution of plasmids along the long cell axis. We show the cases for N = 3 ~ 6. The regular positioning of plasmids is achieved due to an effective inter-plasmid repulsive force and an effective repulsive force from the boundaries. A plasmid i is localized around a fixed position  and they appear to get arranged at an interval determined by . 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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f3-7_77: Distribution of plasmids along the long cell axis. We show the cases for N = 3 ~ 6. The regular positioning of plasmids is achieved due to an effective inter-plasmid repulsive force and an effective repulsive force from the boundaries. A plasmid i is localized around a fixed position and they appear to get arranged at an interval determined by . 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: Observation of such regular positioning of plasmids are not restricted to the cases of N = 1 and 2. For N > 2, stable regular distributions are formed as a result of the generation of the gradient of u(r) by each plasmid. Figure 3 shows the distributions of u(r) and plasmids for N = 3~6 along the long cell axis. Similarly, regular distribution of plasmids is achieved. A plasmid i is localized around a fixed position and they appear to get arranged at an interval determined by (Fig. 3).


Chemophoresis as a driving force for intracellular organization: Theory and application to plasmid partitioning
Distribution of plasmids along the long cell axis. We show the cases for N = 3 ~ 6. The regular positioning of plasmids is achieved due to an effective inter-plasmid repulsive force and an effective repulsive force from the boundaries. A plasmid i is localized around a fixed position  and they appear to get arranged at an interval determined by . 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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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036777&req=5

f3-7_77: Distribution of plasmids along the long cell axis. We show the cases for N = 3 ~ 6. The regular positioning of plasmids is achieved due to an effective inter-plasmid repulsive force and an effective repulsive force from the boundaries. A plasmid i is localized around a fixed position and they appear to get arranged at an interval determined by . 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: Observation of such regular positioning of plasmids are not restricted to the cases of N = 1 and 2. For N > 2, stable regular distributions are formed as a result of the generation of the gradient of u(r) by each plasmid. Figure 3 shows the distributions of u(r) and plasmids for N = 3~6 along the long cell axis. Similarly, regular distribution of plasmids is achieved. A plasmid i is localized around a fixed position and they appear to get arranged at an interval determined by (Fig. 3).

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