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Team:Bologna/Wetlab
From 2008.igem.org
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LAB Experiment
In our genetic bi-stable, the amount of molecules produced to switch the system from the two possible steady state is ruled by LacI and TetR protein. The production of LacI molecules by UV induction can be tested replacing the LacI gene by GFP, so it is possible to have a relation of the strength of LacI synthesis measuring the value of its fluorescence. BBa_K079049 and BBa_K079050 are two new construct submitted to the registry by Bologna’s Igem Team 2008. These UV test circuits can be presented schematically by the following sequence:
- Promoter Constitutive Family: BBa_J23118 (1429 strength ) or BBa_23100 (2547 strength);
- LexA Operator Site Binding (K079040 ) ;
- Rbs with Green fluorescence Protein LVA and Terminator (BBa_I763020)
In order to generate the induction by Uv, a box with UV lamp was realized.
UV Side Effect
In addiction to the germicidal effect UV radiation can also cause erythema (reddening of the skin)
and conjunctivitis (inflammation of the mucous membranes of the eye). Because of this,exist limit
to the exposure[1]that depends by the irradiance of the ultraviolet- lamps(next figure).
Homemade UV transilluminator
When this device are used, it is important to design systems to exclude UV-C leakage and so avoid figure 4: Ultraviolet treshold limited value figure 5: Permissible ultraviolet exposure these effects.The UV source that have been used in this project is a GW6 Sylvania, a lamp that emitt UVC at 253,7nm near the absorption's peak of DNA with an optical output power of 1,6W; to use it safely we built a box of mdf(medium density-fibreboard) that surrounds the lamp and using a diaphragm that allows passage only to the light absorbing the remainder. Moreover we insert in that box two pierced brackets, those permits to choose the distance between the lamp and the sample and then in accord with the Lambert-Beer law's the exposure time.
Finally we embedded this structure in a polistyrene box for its handling and greater safety.(figure 6)
