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Understanding the link between single cell and population scale responses of Escherichia coli in differing ligand gradients.

Edgington MP, Tindall MJ - Comput Struct Biotechnol J (2015)

Bottom Line: We then study the response of cells in the presence of two different chemoattractants.In doing so we demonstrate that the population scale response depends not on the absolute concentration of each chemoattractant but on the sensitivity of the chemoreceptors to their respective concentrations.Our results show the clear link between single cell features and the overall environment in which cells reside.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics & Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX, UK.

ABSTRACT
We formulate an agent-based population model of Escherichia coli cells which incorporates a description of the chemotaxis signalling cascade at the single cell scale. The model is used to gain insight into the link between the signalling cascade dynamics and the overall population response to differing chemoattractant gradients. Firstly, we consider how the observed variation in total (phosphorylated and unphosphorylated) signalling protein concentration affects the ability of cells to accumulate in differing chemoattractant gradients. Results reveal that a variation in total cell protein concentration between cells may be a mechanism for the survival of cell colonies across a wide range of differing environments. We then study the response of cells in the presence of two different chemoattractants. In doing so we demonstrate that the population scale response depends not on the absolute concentration of each chemoattractant but on the sensitivity of the chemoreceptors to their respective concentrations. Our results show the clear link between single cell features and the overall environment in which cells reside.

No MeSH data available.


Related in: MedlinePlus

Plots demonstrating the ability of simulated E. coli cells to accumulate in response to both MeAsp and serine concentration gradients. Shown here are typical cases in which both MeAsp and serine are present within the same domain. In (A) we consider a constant concentration of serine across the whole domain, thus demonstrating the ability of simulated cells to respond to a MeAsp concentration gradient. In (B) we consider a constant concentration of MeAsp across the entire domain, thus showing that cells are able to respond to a serine concentration gradient. Within each plot green and red crosses indicate the starting and final locations of each simulated cell, respectively whilst contour lines and colour bars show the concentration of the non-constant ligand across the domain. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
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f0045: Plots demonstrating the ability of simulated E. coli cells to accumulate in response to both MeAsp and serine concentration gradients. Shown here are typical cases in which both MeAsp and serine are present within the same domain. In (A) we consider a constant concentration of serine across the whole domain, thus demonstrating the ability of simulated cells to respond to a MeAsp concentration gradient. In (B) we consider a constant concentration of MeAsp across the entire domain, thus showing that cells are able to respond to a serine concentration gradient. Within each plot green and red crosses indicate the starting and final locations of each simulated cell, respectively whilst contour lines and colour bars show the concentration of the non-constant ligand across the domain. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Mentions: To check cells within our model respond both to MeAsp and serine we conducted simulations in which one spatially varied whilst the other was held constant. This gave the result in Fig. 9 and confirmed the model exhibited the expected behaviour.


Understanding the link between single cell and population scale responses of Escherichia coli in differing ligand gradients.

Edgington MP, Tindall MJ - Comput Struct Biotechnol J (2015)

Plots demonstrating the ability of simulated E. coli cells to accumulate in response to both MeAsp and serine concentration gradients. Shown here are typical cases in which both MeAsp and serine are present within the same domain. In (A) we consider a constant concentration of serine across the whole domain, thus demonstrating the ability of simulated cells to respond to a MeAsp concentration gradient. In (B) we consider a constant concentration of MeAsp across the entire domain, thus showing that cells are able to respond to a serine concentration gradient. Within each plot green and red crosses indicate the starting and final locations of each simulated cell, respectively whilst contour lines and colour bars show the concentration of the non-constant ligand across the domain. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660157&req=5

f0045: Plots demonstrating the ability of simulated E. coli cells to accumulate in response to both MeAsp and serine concentration gradients. Shown here are typical cases in which both MeAsp and serine are present within the same domain. In (A) we consider a constant concentration of serine across the whole domain, thus demonstrating the ability of simulated cells to respond to a MeAsp concentration gradient. In (B) we consider a constant concentration of MeAsp across the entire domain, thus showing that cells are able to respond to a serine concentration gradient. Within each plot green and red crosses indicate the starting and final locations of each simulated cell, respectively whilst contour lines and colour bars show the concentration of the non-constant ligand across the domain. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Mentions: To check cells within our model respond both to MeAsp and serine we conducted simulations in which one spatially varied whilst the other was held constant. This gave the result in Fig. 9 and confirmed the model exhibited the expected behaviour.

Bottom Line: We then study the response of cells in the presence of two different chemoattractants.In doing so we demonstrate that the population scale response depends not on the absolute concentration of each chemoattractant but on the sensitivity of the chemoreceptors to their respective concentrations.Our results show the clear link between single cell features and the overall environment in which cells reside.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics & Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX, UK.

ABSTRACT
We formulate an agent-based population model of Escherichia coli cells which incorporates a description of the chemotaxis signalling cascade at the single cell scale. The model is used to gain insight into the link between the signalling cascade dynamics and the overall population response to differing chemoattractant gradients. Firstly, we consider how the observed variation in total (phosphorylated and unphosphorylated) signalling protein concentration affects the ability of cells to accumulate in differing chemoattractant gradients. Results reveal that a variation in total cell protein concentration between cells may be a mechanism for the survival of cell colonies across a wide range of differing environments. We then study the response of cells in the presence of two different chemoattractants. In doing so we demonstrate that the population scale response depends not on the absolute concentration of each chemoattractant but on the sensitivity of the chemoreceptors to their respective concentrations. Our results show the clear link between single cell features and the overall environment in which cells reside.

No MeSH data available.


Related in: MedlinePlus