Transcriptional control of motility enables directional movement of Escherichia coli in a signal gradient

Jayamary Divya Ravichandar,Cynthia H Collins,A Agung Julius,Adam G Bower

doi:10.1038/s41598-017-08870-6

Jayamary Divya Ravichandar, Cynthia H Collins + Show 2 more

Open Access

https://doi.org/10.1038/s41598-017-08870-6

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Abstract

Manipulation of cellular motility using a target signal can facilitate the development of biosensors or microbe-powered biorobots. Here, we engineered signal-dependent motility in Escherichia coli via the transcriptional control of a key motility gene. Without manipulating chemotaxis, signal-dependent switching of motility, either on or off, led to population-level directional movement of cells up or down a signal gradient. We developed a mathematical model that captures the behaviour of the cells, enables identification of key parameters controlling system behaviour, and facilitates predictive-design of motility-based pattern formation. We demonstrated that motility of the receiver strains could be controlled by a sender strain generating a signal gradient. The modular quorum sensing-dependent architecture for interfacing different senders with receivers enabled a broad range of systems-level behaviours. The directional control of motility, especially combined with the potential to incorporate tuneable sensors and more complex sensing-logic, may lead to tools for novel biosensing and targeted-delivery applications.

Highlights

Cellular motility is a key microbial behaviour with a broad range of functions in natural systems, including navigation of the environment[1], biofilm formation[2], and control of biodiversity in consortia[3]
To build a system where the motility of E. coli is transcriptionally regulated by quorum sensing (QS) components, we used the esa QS system to control expression of MotA in an E. coli motA deletion strain (∆motA)[39]
The green fluorescent protein was placed downstream of PesaR to allow characterization of expression from PesaR, if motA expression was not sufficient to provide detectable motility in our assays. This strain is designated as the Communication-dependent Motility (CoMot) strain

Summary

Introduction

Cellular motility is a key microbial behaviour with a broad range of functions in natural systems, including navigation of the environment[1], biofilm formation[2], and control of biodiversity in consortia[3]. Of an E. coli signalling domain and a sensory domain from other species that recognizes a target compound[25] While such strategies for controlling directional movement targeting E. coli’s chemotactic network have led to some success, the limited number of natural chemoreceptor scaffolds imposes constraints on ligands that can be targeted. Such engineering challenges have led to alternative approaches, such as converting the desired target to a compound recognized by E. coli’s native chemotactic machinery[26]

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Conclusion