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Cohesion

Purpose

To facilitate the efficiency and effect of killing part and anti-biofilm part, we design the cohesion module. It could attach our modified E. coli to the surface of the S. mutans, so that we could shorten the distance between our helper E.coli and our targeted enemy, S. mutans, and evaluate the efficiency of other mechanism, the “Completion” part in our project.

For Completion-killing part, when the helper E. coli received the signal send by modified phage, the antibiotic secreted E. coli by can kill the S. mutans faster if they are close to each other. Additionally, for Completion-antibiofilm part, E. coli can sense the increase of biofilm formation in a shorter time and activate the antibioflim module.In conclusion, the “Cohesion” part able the E. coli to serve like supervisors around S. mutans and shorten the time and distance of attacking.

Background

To make E. coli a supervisor to control the population of S. mutans, we have to find anchor to attach E. coli to S. mutans. Thus, we take advantage of CSP. CSP is a kind of quorum sensing pheromone, which enables Streptococcus mutans to alter their gene expression when the critical density of cell population is reached. Recent studies showed that density-dependent quorum sensing (QS) system primarily comprised of the Competence Stimulating Peptide (CSP) and the ComD/ComE two-component signal transduction system. In addition to biofilm formation, the CSP-mediated QS system in S. mutans also affects its acidogenicity, aciduricity, genetic transformation and bacteriocin production. Most importantly,CSP is specificly secreted by S. mutans, which is the reason we choose it as anchor targeting S. mutans.

Design

We use competence stimulating peptide (CSP), as a targeting material to attach E. coli to the surface of Streptococcus mutans. To do so, we use Surface display protein INPNC (designed by 2011 iGEM Edinburgh team) to display CSP on the membrane of E. coli, which act as the “anchor”. CSP binds to the receptors on the surface of Streptococcus mutans, and so is to our engineered helper E. coli.

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Result

Reference

1. Targeted Killing of Streptococcus mutans by a Pheromone-Guided “Smart” Antimicrobial Peptide(2006)Randal  Eckert1, Jian He2, Daniel K. Yarbrough2, Fengxia Qi2,Maxwell H. Anderson3 and Wenyuan Shi
2. Quorum sensing and biofilm formation by Streptococcus mutans. Senadheera.(2008) D1, Cvitkovitch DG