Difference between revisions of "Part:BBa K3201020"

Latest revision as of 23:32, 21 October 2019

pBAD-araC STAR target with aadA and KanR

This is an AND gate consisting of the arabinose inducible promoter and the STAR target. In the presence of arabinose and STAR, the expression of 2 antibiotic resistance genes is initiated.

Usage and Biology

This AND gate was incorporated in order to provide the means to overcome the evolutionary pressure exerted by antibiotics. We transformed bacteria with a vector containing the AND gate and the STAR and qualitatively observed whether it could work. We grew the bacteria in 0.1% arabinose, 50 µg/mL Streptomycin, and 25 μg/mL Kanamycin. Under these conditions the antibiotic genes were expected to be expressed. Indeed, as shown in Figure 1, the culture appeared cloudy.

Figure 1: Culture grown with 0.1% arabinose, 50 µg/mL Streptomycin, and 25 μg/mL Kanamycin

Using an inoculation loop, a sample was taken and spread onto a plate that contained no antibiotic. We did this to observe all viable cells. It appears that the AND gate functioned normally and some cells express the antibiotic genes, as shown in Figure 2.

Figure 2: A sample of liquid culture was spread onto an agar plate containing no antibiotics.

As a control, we spread a sample of bacteria grown under the same conditions, but without arabinose. The plate itself contained 1% arabinose and Streptomycin but it seems that it was not enough to allow the cells to begin the expression of the aadA gene (resistance to Streptomycin) and therefore no viable cells were observed.

Figure 3:

Sequence and Features