Team:HIT-Harbin/project/part3

     Biofilms are groups of cells at an interface cemented together by polysaccharides, protein, DNA and lipids. It enhances bacteria’s resistance to environmental stress and is able to perform more complex transformations[1]. In our system, detecting part and killing part are separated into two different engineered E.coli populations. As we know, people in a small room communicate more conveniently than in a big one. We assume that signal transduction between E.coli is similar to people’s communication. In order to strengthen signal transduction between two communities, we construct an enhanced consortium biofilm.

Fig. 1 the biobrick of biofilm formation device.

    We introduce a gene yddV, which is under the regulation of Ptrc promoter (IPTG-inducible) (Fig. 1). yddV is a Diguanylate Cyclase-Genomic. The product of gene yddV has diguanylate cyclase (DGC) activity. DGC uses 2 GTP to form a bis-(3’-5’)-cyclic dimeric guanosine monophosphate (c-di-GMP)[2].

    C-di-GMP is a global second messenger in bacteria. Biofilm formation of E.coli is manipulable by varying c-di-GMP concentrations. When the c-di-GMP level stays low, there is little biofilm and the bacteria is dispersive. High concentration of c-di-GMP promotes bacteria to form more cellulose and fimbriae, which enhances the biofilm formation and decrease the motility of bacteria.

Reference:

[1] Hyun-Dong Shin, Shara McClendon, Trinh Vo, and Rachel R. Chen．Escherichia coli Binary Culture Engineered for Direct Fermentation of Hemicellulose to a Biofuel[J]. Applied and Environmental Microbiology, 2010, 76(24):8150-8159.

[2] M. Marcela Me´ndez-Ortiz, Mamoru Hyodo, Yoshihiro Hayakawa, and Jorge Membrillo-Herna´ndez．Genome-wide Transcriptional Profile of Escherichia coli in Response to High Levels of the Second Messenger 3,5-Cyclic Diguanylic Acid[J]. The Journal of Biological Chemistry, 2006, 281(12):8090-8099.