Template:Team:KULeuven/23 September 2009/BlueLightReceptor

From 2009.igem.org

measurements of the liquid cultures from 22/09 were made. the empty top10, and standard promoter I20260 were measured. then, at different times likA were measured.

we concluded the following from our measurements:

the gfp at time 0 was already pretty high
the level of gfp did not change during lighting.
the level of gfp measured was not higher then the gfp signal from I20260.

after having read some of the articles about this system again we made some new discoveries about the receptor (YcgF), the repressor (YcgE) and the promotor (blp):

temperature seems to be more important then we first suspected. not only does temperature influence the expression of YcgF/E but it also influences the dimerization of YcgF. It seems that the colder the temperature, the easier dimerization (in the absence of light) happens.
this finding made us conclude the following about temperatures in our experimental set up.
- growing cells at 37°c: at this temperature the repressor has a very low expression rate. thus, the number of plasmids containing a promoter (15-30) is too big compared to the amount of repressor.
- putting cells in 16°c: the amount of repressor produces might be enough to cover all the promoters but there will be at least as much receptor that is dimerized and tus active to undo this repression.
- conclusion: growing aty 25° gives the possibility of creating enough repressor/receptor without having the receptor in an active state and removing the repressor activity.