Revision as of 16:51, 9 June 2015

Project Overview

We are interested in developing an autonomous antibacterial system using an E. coli chassis through synthetic biology. Our antibacterial strategy involves a two-step mechanism:

i) Destroy the bacterial biofilm which confers the bacteria encased within significantly increased resilience against antibiotics.

ii) Destroy the liberated bacteria by directly lysing their cell walls.

We will be experimenting with antibacterial action against E. coli and P. aeruginosa.

Antibiofilm action

The cartoon above shows two of the major structural components of bacterial biofilms - extracellular polymeric substance (a.k.a. EPS, in blue) and extracellular DNA (in pink). The Doctorbacto system will release the following enzymes targeting these structural components:

Dispersin B	Destroys E. coli biofilms by hydrolysing beta-1,6-N-acetyl-D-glucosamine, which is the major EPS in E. coli biofilms
Thermonuclease	Also commonly known as staphylococcal nuclease, this enzyme should be able to destroy P. aeruginosa biofilms by hydrolysing its extracellular DNA (novel usage, untested as of yet)

Antibacterial action

Doctorbacto will release "artilysins", which is a class of combination biomolecules made by fusing endolysins (phage-derived enzymes that hydrolyse bacterial cell walls) with SMAP-29 (a transporter peptide that brings the complex through the bacterial outer membrane such that it can get in contact with the cell wall). Endolysins are species-selective in terms of the type of cell wall which they hydrolyse, and as such Doctorbacto will be making two different artilysins:

Art-175	An artilysin specific for P. aeruginosa comprising endolysin KZ-144 and SMAP-29, invented in 2013
Art-E	An E. coli-specific artilysin, comprising T4 endolysin and SMAP-29, conceptualized and designed by our team (novel design, untested as of yet)

Overall design

We intend to construct two variations of Doctorbacto - one that synthesizes and accumulates the antibacterials and antibiofilms within itself before releasing them all by self-lysing upon detection of the presence of group pathogenic bacteria behaviour (via quorum sensing), and another one that constantly secretes moderate levels of both antibacterials and antibiofilms. With the secretor design, we are also interested in studying the secretion efficiency of our biomolecules of interest through different secretion mechanisms.

Potential applications

The original inspiration that led us down the path of looking at biofilms contributing to the overarching problem of antibiotic resistance was George (one of our team members)'s experience from working at a urinary tract infection (UTI) clinic, hence we are definitely interested in exploring how we can incorporate this biotechnology as a form of prophylactic application for preventing recurrent, nasty biofilm-mediated infections from forming on indwelling urinary catheters. Other than that, Doctorbacto can also potentially be used in antibiofilm plasters or even industrial contexts such as self-cleaning, antifouling pipelines.