Week 6

From 2007.igem.org


  • Miniprep for P0412 and R0010.
  • We inoculate a colony of J04431 in 5ml to perform the fluorescence test with glucose (see the following protocol).

J04431 bacteria from glycerol stock:

-growth of 10 aliquots (1 ml/each) at 37°C for 1h;

-collection of 5ml in 2 tubes;

-fluorescence control: bacterial cells from one tube are fluorescent and cells from the other are not;

-add glucose 2mM in each falcon;

-incubation at 37°C for 1h;

-there are no fluorescent bacteria in the two cultures;

-after 2h the fluorescence is the same.

We check bacteria from the stock and we see that some of them are fluorescent, even if we don’t expect this result.

  • We strake on plates from falcon with glucose, we discard the supernatant, we clean in LB for 2 times, we re-suspend in 5ml of LB. Bacteria become fluorescent. When we add 2mM of glucose bacteria are not fluorescent.

So, it is possible to control PLac activation with glucose. As it is known from literature, endogenous LacI is not sufficient to repress the PLac promoter in a high copy number plasmid since a small amount of glucose increases the kinetic ratio of PLac transcription. We are going to insert LacI in our construct to solve this problem. This test enables us to verify GFP half-life which is about 40 minutes.

  • Model analysis.