Team:BS United China/Engineering

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Engineering Success

Design

Pathogenic microorganisms are ubiquitous in our everyday environment. P. aeruginosa was selected as the vaccine strain as it is one of the most common food pathogens to form biofilms. We initially combine both E. bsuahlscout and E. bsuahlterminator. As shown in figure1, we make QS DDD consist of T7 promoter, Lac operator, LuxR, QS promoter, mCherry, QS promoter, PVDQ, and GFP as a whole cycle.

However, after the interview with a branch manager of Yonghui superstore, use E. bsuahlscout to identify the level of freshness of food will be better to achieve. The PVDQ protein in E. bsuahlterminator can also extend the food shelfl-life. As a result, we separate the whole cycle into two parts.

E. bsuahlscout, which is synthesized by Beijing Genomics institution, aims at quantize the degree of food pollution.

E. bsuahlterminator , synthesized by Beijing Genomics institution, is a fused protein, as shown in figure2.

In order to determine whether the engineering bacteria have a growth rate that differs from the growth rate of the E. coli, the graph is shown below. With the main theory that the bacteria would absorb light and would show absorption at particular wavelengths of light, we set a goal of the test of the growth curve to show that the addition of the biobricks into the bacteria would not affect the growth rate of the bacteria. Separately, the figure3 represent the growth curve of P. aeruginosa, E. coli, E. bsuahlscout, E. bsuahlterminator.

We also measure the effectiveness of the PVDQ proteins on the reduction of the P. aeruginosa by adding PVDQ proteins produced by part 2 engineering bacteria into the solution containing P. aeruginosa. The absorption value are measured and intensity is calculated. (Figure 5)

Build


Fig.1 construction of E. bsuahlscout Fig.2 construction of E. bsuahlterminator Fig.3 The growth curve of the P. Aeruginosa(Left top)The growth curve of the E. coli(Right top)The growth curve of the AHL scout(Left bottom)The growth curve of the AHL terminator(Right bottom Fig.4 Comparasion of the growth rates of the four kinds of bacteria Fig.5 Fig.6 The change of bacteria intensity after treated by high protein concentration(50ng/ul) Fig.7 The change of bacteria intensity after treated by medium protein concentration(25ng/ul) Fig.8 The change of bacteria intensity after treated by low protein concentration(5ng/ul)

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When the time increases, the absorption value rises gradually. It shows the positive correlated relationship. According to the best-fit line of E. bsuahlscout and E. bsuahlterminator, the positive correlated and upward shapes are similar to the shape of E. coli in the 16-hours duration. It confirmed that the Engineering Bacteria have the similar growth rate to E. coli. From the figure 4, three lines are almost overlapped which can show same growth rate.

According to figure 6, when proteins are in the first wash, it has the highest concention so PVDQ proteins’ effectiveness on the reduction of P. aeruginosa is relatively stronger when concentration is high. In comparison, the 5th and 8th wash has a less stepper gradient than the control group. Therefore, they have a weaker reduction effect but still have the effectiveness. In conclusion, PVDQ protein is relatively effective to reduce the volume of P. aeruginosa.