During the designation of the experiment for our pH alert system, we have concluded
that we should try to improve the expression of our pH-sensitive promoter, promoter
gadA. The motivation for us to do this is because our team think that if we can build a
system which could observe the situation in our device by looking at the color change
of the medium, it should be an economic friendly as there is no more extra charges to
send your sample to someway for checking and also wasting a lot of time for waiting the
result. But according to the expression of promoter gadA from the previous team did, it
is not enough to be observed by using our eyes.
Based on our research, RiboJ first described as it is an insulator in genetic
construct but there has no any data shown this insulation effected the downstream
genetic parts. In 2018, there is a team have proved that RiboJ could increase the
expression of downstream gene and there is the team member, Kalen P Clifton#1,
Ethan M Jones#1, Sudip Paudel1, John P Marken2, Callan E Monette1, Andrew D
Halleran2, Lidia Epp1, Margaret S Saha1*. Hence, our team, NCKU_Tainan have desided
to enhance the expression and specificity of promoter gadA by adding a gene, RiboJ
at the downstream of promoter gadA.
For the function determination, we have measured the fluorescent
density of the plasmid with and without RiboJ in different pH environment. We
incubated the bacteria in pH adjacent M9 medium and measure the fluorescent
intensity (absorbance: 480nm, excitation: 510 nm) in a short period of time.
Figure 3: The fluorescent intensity between PgadA and PgadA-RiboJ
in pH6 and pH 7.