Team:HIT-Harbin/project

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HIT-Harbin

Project Overview

    Staphylococcus aureus infections are major causes of morbidity and mortality in community and hospital settings. Consequently, the emergence of methicillin-resistant and, more recently, vancomysin-resistant strains of S.aureus represents an enormous threat to public health. Since bacterial sensors are attracting more and more biologists' attention owing to its' specific, fast and accurate detecting, we plan to construct a E.coli biofilm consisting of two different engineered populations(namely biosensor and killer), which are designed to detect and eradicate S.aureus, respectively. The two engineered populations communicate with each other by AHL signal transduction. We hope that compartmentalization of functions can lessen metabolism load and cross-reactions interfere, and achieve the assembly of different functions in bacterial level. The whole system comprises sensing, killing and biofilm formation devices.

    Detecting device: to detect the existence of S.aureus through sensing the AIPs secreted only from S.aureus, and the report will be shown by the expression of GFP.

    Killing device: to eradicate S.aureus through the production and release of lysostaphin.

    Biofilm formation device: to enhance biofilm formation by over-expression of yddV, a di-guanylate cyclase, which catalyzes GTP into c-di-GMP.

Fig. 1 Schematic of “S.aureus monitor” system. The AgrA protein is phosphorylated when AIP binds to AgrC protein across the membrane. P2(P3) is activated by phosphorylated AgrA, leading the production and release of 3OC6HSL. PluxI promoter is induced by LuxR-3OC6HSL complex, causing the production of lysostaphin and starting the time-delay device(PKU iGEM 2010). After a certain time, lysis E7 protein(NTU iGEM 2009) is produced. After the E7 protein attains the threshold concentration that causes the chassis to lyse, the accumulated lysostaphin is released into the exogenous environment and kills S.aureus. T5:constitutive promoter; P2(P3):AgrA~P inducible promoter; Ptrc:IPTG inducible promoter; PluxI:LuxR-3OC6HSL complex inducible promoter; AIP: produced by Staphylococcus aureus

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