Difference between revisions of "Part:BBa K395304:Experience"

Tokyo Tech iGEM2010

Figure 1. Induction of new OmpC series in high osmolarity medium at 4 hours. This work is done by Thiprampai THAMAMONGOOD and Taichi NAKAMURA Tokyo Tech iGEM2010

In order to characterize PompC(C) BBa_395301, PompC(CB) BBa395302 and PompC(CS1) BBa_395303, each promoter was attached to GFP and its transcriptional activity was measured through the GFP expression.

PompC(C)-GFPBBa_395304 , PompC(CB)-GFP BBa_395305, PompC(CS1)-GFP BBa_395306and PompC(WT)-GFPBBa_395307 on pSB3K3 was introduced into E. coli strain MG1655. A strain containing placI^q-GFP, plasmid (BBa_J54202), a constitutive GFP expressive promoter and promoterless GFP reporter plasmid (BBa_J54103) were used as a positive control and negative control respectively.

Overnight cultures of reporter strains grown at 37 °C in Medium A containing appropriated antibiotics were diluted at least 1:100 in the medium and incubated at 37 °C as fresh cultures. After their OD₅₉₀ reached 0.2, the fresh culture was diluted 1 : 3 into 2 ml of pre-warmed medium A. For high osmolarity conditions, the cultures were diluted with sucrose supplemented medium to the final concentration of 15% (wt/vol). After 4 hours of induction, fluorescence intensity was measured with fluorometer.

After 4 hours of high osmolarity induction by sucrose, transcriptional activity of PompC(CB)-GFP and PompC(CS1)-GFP increased 2.5 folds and 2.3 folds respectively. However, significant amount of leaky expression was found in PompC(CS1)-GFP without induction. In contrast, under the same conditions, we found no significant difference of GFP expression in PompC(C)-GFP. Although, PompC(WT)-GFP also doesn't show the difference in expression of GFP at 4 hours of induction, there was slightly higher GFP expression 1.7-folds occurred in the wild type at 2 hours. We considered that the transcriptional activity of PompC(WT)-GFP increased in particular period and declined after it reached the peak of expression. This result also shows the relation to the study by the Edinburgh team iGEM 2009.[http://2010.igem.org/Team:Tokyo_Tech/Project/wolf_coli/New_Series_of_PompC ...see more about PompC series]