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

TL;DR

This paper explores how individual Escherichia coli cells and their population respond to different chemical gradients, linking single-cell behavior to population-level outcomes.

Contribution

The study introduces an agent-based model that connects single-cell signaling dynamics to population-scale responses in varying chemoattractant gradients.

Findings

Variation in total signaling protein concentration helps cells survive in diverse environments.

Population responses depend on receptor sensitivity, not absolute chemoattractant concentration.

Single-cell features directly influence population behavior in different chemical environments.

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.

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