Ehime-Japan iGEM Team: Welcome


In our experiment of the, the important thing is to degrade GFP-Lon-tag more rapidly. GFP is usually stable and has a long half–life. So, we thought of how to measure the reaction rate.


E.coli (pIJ106b, pJT122, plPCB) is cultivated in TY culture medium for 7 hours. It was precipitated by centrifugation and washed with 1 % NaClaq. 400 μL of 1% NaCl was added to the E.coli sample. An aliquot from each sample was plated on agar and cultured overnight. The solution was exposed to blue LED light, and we took a color picture every 1 hour for 6 hours. By using the ImageJ software, we measured the intensity of light from GFP.


The relative light intensity values are summarized in Table 1. As we can only obtain relative values as intensity of light, we set the value for the 0-hour sample as 1.

TABlE 1 Intensity of light

Fig  Relation between Intensity of light and time
We did not use date of 5 hour and 6 hour.


Because there is the propotional relationship between light intensity and GFP concentration, we made a graph of this and took collinear approximation. Besides considering parameter, three is this approximation straight line is primary rate equation.

(d [GFP-Lon tag])/dt = -k1 [GFP-Lon tag][Lon-LVA]
(d [Lon-ClpXP])/dt = -k2 [Lon – LVA][LVA] +Lon synthesis rate