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This article is part of the supplement: BioSysBio 2007: Systems Biology, Bioinformatics, Synthetic Biology

Open Access Oral presentation

Navigational control of bacteria: the design of a synthetic chemotactic biological system

James Brown

Author Affiliations

Department of Plant Science, University of Cambridge, Cambridge, CB2 3EA, UK

Department of Engineering, University of Cambridge, Cambridge, CB2 31PZ, UK

BMC Systems Biology 2007, 1(Suppl 1):S14  doi:10.1186/1752-0509-1-S1-S14


The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1752-0509/1/S1/S14


Published:8 May 2007

© 2007 Brown; licensee BioMed Central Ltd.

Background

Synthetic Biology is a rapidly developing field, which sees engineering principles applied to natural biological systems with a view to re-engineer them for useful purposes. This study focused on chemotaxis, the natural directed motion of a micro-organism toward environmental conditions it deems attractive, with an aim of demonstrating external navigational control over E. coli bacteria. The concept has potential long-term applications in a range of fields, including biological and environmental sensors, drug discovery and the maintenance or enhancement of human health.

Method

The periplasmic maltose-binding protein (MBP) is essential for maltose transport and taxis. It was placed under external control via synthetic plasmids containing 2 different IPTG-based promoters coupled to the MBP-encoding malE and malE31 [1] genes. These were transformed into three engineered ΔmalE E. coli strains allowing for both permanent and temporary reactivation of maltose chemotaxis. The stochastic simulator StochSim [2] was adapted from the standard aspartate model to consider the associated maltose regulon.

Results

The re-engineering of the natural chemotaxis system was successfully demonstrated on both the macro and micro scale using swimming and agarose plug assays. It was shown maltose chemotaxis could be initiated and repressed by an external signal. Stochsim was successfully adapted to model the maltose system, with simulation data for the adaptation and dependence on MBP shown to closely match experimental data [3].

Conclusion

A novel approach demonstrated the feasible control of the sensory system and resultant motile behaviour of synthetically engineered E. coli cells. This provides an appropriate tool for generating experimental data that in turn may feed the computational modelling of chemotaxis. This allows a better understanding of the natural system and how one might go about specifically engineering that system for a useful cause.

References

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  2. Morton-Firth CJ, Shimizu TS, Bray D: A free-energy-based stochastic simulation of the tar receptor complex.

    J Mol Biol 1999, 286:1059-1074. PubMed Abstract | Publisher Full Text OpenURL

  3. Manson MD, Boos W, Bassford PJ Jr, Rasmussen BA: Dependence of maltose transport and chemotaxis on the amount of maltose-binding protein.

    J Biol Chem 1985, 260:9727-9733. PubMed Abstract | Publisher Full Text OpenURL