Intra-Species Bacterial Quorum Sensing Studied at Single Cell Level in a Double Droplet Trapping System

• Main Authors: Wilhelm T. S. Huck, Chris Abell, Martin Welch, George P. C. Salmond, Jie Pan, Simon Poulter, Santoshkumar N. Patil, Steven D. Bowden, Yunpeng Bai
• Format: Article
• Language: English
• Published: MDPI AG 2013-05-01
• Series: International Journal of Molecular Sciences
• Subjects: droplet-based microfluidics; bacterial quorum sensing; single cell
• Online Access: http://www.mdpi.com/1422-0067/14/5/10570

In this paper, we investigated the intra-species bacterial quorum sensing at the single cell level using a double droplet trapping system. Escherichia coli transformed to express the quorum sensing receptor protein, LasR, were encapsulated in microdroplets that were positioned adjacent to microdroplets containing the autoinducer, N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL). Functional activation of the LasR protein by diffusion of the OdDHL across the droplet interface was measured by monitoring the expression of green fluorescent protein (GFP) from a LasR-dependent promoter. A threshold concentration of OdDHL was found to induce production of quorum-sensing associated GFP by E. coli. Additionally, we demonstrated that LasR-dependent activation of GFP expression was also initiated when the adjacent droplets contained single E. coli transformed with the OdDHL synthase gene, LasI, representing a simple quorum sensing circuit between two droplets.