Team:Toulouse/Project/Chemotaxis

What is chemotaxis?

Chemotaxis is a bacterial function which allows bacteria to move according a concentration gradient. With this system bacteria can find better place to grow by swimming toward higher concentrations of molecules, such as nutritional molecules like sugar, amino acid, vitamins...
In our case, chemotaxis is used as a way to detect and approach fungus. Indeed during its growth, fungi release N-acetylglucosamine, a monomer of chitin which is specific to fungal presence. Thus, there is a gradient of N- acetylglucosamine around fungi.

Unfortunately Bacillus subtilis is not able to detect such gradient, but Bacillus is able to detect and to move towards sugar like glucose thanks a glucose specific receptor, VcpA. But other bacteria can detect these kind of molecule, for example Vibrio cholerae, which has a specific receptor for N- acetylglucosamine, VCD.

Therefore, our idea is pretty simple, we switch glucose specificity by N-acetylglucosamine specificity. So we need to modify the extracellular part of VcpA, the part which is responsible of the specificity, by the extracellular part of a N-acetylglucosamine receptor, VCD.

References

- K. Meibom,L. Xibing, A. Nielsen, CY. Wu, S. Roseman and G. Schoolnik. The Vibrio cholerae chitin utilization program . The National Academy of Sciences of the USA (2004).
-C. Kristich and GW. Ordal.Bacillus subtilis CheD is a chemoreceptor modification enzyme required for chemotaxis. J Biol Chem. 2002 Jul 12;277(28):25356-62. Epub 2002 May 13.

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