Team:ULB-Brussels/Project

From 2009.igem.org

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[https://2009.igem.org/Team:ULB-Brussels/Projet/Material Material and Methods]
 
[https://2009.igem.org/Team:ULB-Brussels/Projet/Introduction Intrdoduction]
[https://2009.igem.org/Team:ULB-Brussels/Projet/Introduction Intrdoduction]
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==Introduction==
 
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Caulobacter crescentus is a gram-negative bacterium studied for the properties of its cell cycle. (reference cycle cellulaire) This bacterium is widely spread in aquatic environments and exists either as a motile cell or as a sessile cell (Figure 1). In the sessile stage, C. crescentus sticks to surfaces by synthesizing adhesive at the stalk, a polar organelle shown in figure 2. At the tip of this appendage, a complex holdfast structure is assembled.
 
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PHOTO 1
 
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This material is an elastic, gel-like adhesive substance composed of both protein and polysaccharide. The N-acetylglucosamine polymer has been identified as the main polysaccharide component. (reference sucre) This holdfast shows unprecedented adhesive properties: a single C. crescentus cell can adhere with a strength up to 68 N/mm2. In comparison, commercial superglue can withstand a force of 18-30 N/mm2. (reference force colle) Since this adhesive adheres to wet surfaces, many industrial applications are foreseen. The glue has already been isolated but the challenge is to produce large amounts of glue without it sticking to the material where it is produced.
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[https://2009.igem.org/Team:ULB-Brussels/Projet/Material Material and Methods]
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A model of holdfast biosynthesis, export and attachment in C. crescentus has already been characterised. (REFERENCE)
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PHOTO 2
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The hfsE hfsF hfsG hfsH genes are organized in operon and their products are required for the minimum repeat unit holdfast synthesis while the polymerization of the repeat unit of the holdfast substance needs the expression of hfsC and hfsI genes.
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The products of the 3 adjacent hfsD hfsA and hfsB genes are involved in the holdfast export and the anchoring of the holdfast polysaccharide is carried out by the hfa gene products. (reference adhesion)
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As Escherichia coli possess 7 similar genes [1]involved in the production and the export of the holdfast in C. crescentus, we only inserted the hfsG and hfsH genes in an E. Coli strain.
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Our aim is to find a way of mass-producing the glue. For this purpose, we planned to transfer the C. crescentus holdfast polysaccharide biosynthesis pathway to Escherichia coli. We built a synthetic E. coli producing the glue: GluColi.
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The problem of stickiness to the material of the container used to produce the glue was not investigated. In fact, we thought it was more relevant to synthesize the glue whenever and wherever it is required, instead of focusing on the extraction of the adhesive. For this purpose, we designed a theoretical circuit using chemotaxis and quorum sensing. The circuit will be presented in the “Biological model” section.
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GluColi started producing an adhesive material and we begun to characterize the glue in the “Physical and chemical properties of our glue” section.
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The “Mathematical design” will also discussed.-->
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Revision as of 12:05, 20 October 2009

iGEM Team:ULB-Brussels Wiki

Intrdoduction


Material and Methods