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Team:Grinnell/Project
From 2011.igem.org
Project
Overall project
Biofilms are cells encased in a hydrated extracellular polymeric substance (EPS) matrix that is composed of polysaccharides, proteins, nucleic acids, and lipids2. Due to its extracellular structure, a biofilm can act as a protective umbrella of its dwellers against various adverse environments and can aid in the communication between cells3. Biofilm has become a great concern for the global communities in recent years in various fields, including health, food industry and environment. The notorious nature of biofilm makes it hard to get rid of at a low cost once a mature biofilm community has envolved. Various pathogenic bacterial biofilm inhabitants or non-pathogenic bacteria but evolve pathogenicity through gene flow among biofilm inhabitants are always a potential danger for human beings.
A synthetic biology approach to inhibit or degrade biofilm formation has been recently taken serious consideration. A couple of previous iGEM teams have been working on engineering proteins that display enzymatic biofilm destruction activities into E. coli and have E. coli synthesize the proteins in vitro. We decide to improve this approach of biofilm growth inhibition by utilizing a novel type I secretion existed in Caulobacter crescentus. C. crescentus is a non-pathogenic gram-negative aquatic environmental-friendly bacterium. Compare to the conventional synthetic biology model organism E. coli, C. crescentus possesses multiple advantages: 1) it is found in freshwater lakes and streams as well as in soil, thus it is able to survive in both aquatic and non-aquatic environments; 2) it is able to grow and reproduce to high density in a low nutrient environment; 3) C. crescentus, although gram-negative, is a non-pathogenic bacterium and has negligible impact on human beings—unlike E. coli (strain O157:H7), it can barely survive at human body temperature; 4) it has been studied for nearly 50 years and the main laboratory strain is well characterized genetically and biochemically11 12 13.
A more notable feature of C. crescentus is its robust type I secretion system. We expect to attach a secretion tag to the biofilm inhibitor protein and therefore not only express the enzymes inside the cell but also export the enzymes to actually destruct biofilms.
For the biofilm inhibitor enzymes that we want C. crescentus to secret, we focus our efforts on a serine protease, Esp, from Staphylococcus epidermidis, and a hydrolase, DspB, from Aggregatibacter actinomycetemcomitans that have both been shown to inhibit biofilms8 9.
The general goal of our project is: 1) to introduce C. crescentus as another potential option for synthetic biology, especially in environmental and biomedical-related fields; 2) to create a toolbox of biobrick parts that enable the system to secret any protein of interest when fused to the C-terminal secretion tag; 3) improve the previous applications of biofilm inhibition biological machine by having a non-biofilm forming and non-pathogenic strain secret biofilm destructor enzymes so that the machine will inhibit biofilm if co-culturing with the biofilm former.
Project Details
