Enunciation of the problem and goals

To perform Arsenic detection, we use some bacteria (E.coli) which are genetically modified to express eGFP protein in presence of Arsenic. Then our prototype detects the fluorescence  emitted (λ=504 nm) by these proteins under an excitation at a specific wavelength (λ=475 nm).

The problem is that excitation and emission wavelengths are too close to be distinguished by the light sensor of our prototype.

One solution to avoid that would be to use another fluorescent protein with a larger Stoke’s shift (LSS) and LSS mOrange has been chosen.

We find the following results in the paper of Shcherbakova, D. M., Hink, M. A., Joosen, L., Gadella, T. W., & Verkhusha, V. V. (2012), "An orange fluorescent protein with a large Stokes shift for single-excitation multicolor FCCS and FRET imaging.", J. Am. Chem. Soc, 134(18), 7913-7923. :

Table : excitation and emission wavelengths for the eGFP and LSS mOrange protein

So the goal of this project is to characterize the LSS mOrange bioreporter, especially its strain, sensitivity to arsenic, time for development, fluorescence activity…

All the strains of bacteria come from Dr. Jan Van der Meer Lab.

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