Team:Worldshaper-Shanghai/Measurement

Measurement

For characterization part, we have re-characterized the biobrick of BBa_K2890006, a device used to detect and degrade formaldehyde. We transformed the part BBa_K2890006 and remeasured its performance of detecting formaldehyde followed by iGEM’s standard measurement protocols. We hope that through our effort this biobrick can be more measurable and reproducible.

Firstly, we established a particle standard curve and fluorescein standard curve to standardize the experiment (Figure 1). By this way, we hope to eliminate the deviations caused by different laboratories and individuals when the functions of engineered strains are measured.

Figure 1. Particle standard curve (a) and Fluorescein standard curve(b).
Figure 1. Particle standard curve (a) and Fluorescein standard curve(b).

In cell measurement part, LB is used as the blank control and empty plasmid as the negative control. Combined with test device, their performance of detecting formaldehyde have been done. In the previous experience, we found that the test group containing the working plasmid (BBa_K2890006) could efficiently survive in the culture media containing formaldehyde. Using the associated Excel data analysis template provided by iGEM measurement committee, the eRFP fluorescence value is standardized as the NET Fluorescein a.u.. Similarly, OD600 is standardized as the Net Abs600. Detailed results are as follows.

As shown in Figure 2, we can see that with the increase of the concentration of formaldehyde, the growth curve of the control group (Figure 2(B)) decreased significantly; while the growth curve of test group (Figure 2(A)) was basically normal. Compared with control group, the bacteria of the test group exhibited higher tolerance to formaldehyde especially at the concentration above 1.6 mM. It could be inferred that the test group had the good potential in degrading formaldehyde.

Figure 2. The growth curve of test group (A) and control group (B)
Figure 2. The growth curve of test group (A) and control group (B)

We also tested the production of eRFP by measuring the fluorescence intensity under the excitation wavelength of 575 nm. The results matched the previous study. According to Figure 3, the fluorescence intensity increased with the increase of formaldehyde concentration, indicating that the module of formaldehyde detection functioned well.

Figure 3. Curve of fluorescence intensity and culture time of the test group
Figure 3. Curve of fluorescence intensity and culture time of the test group

Conclusion

In order to eliminate the deviations caused by different laboratories and individuals when the functions of engineered strains are measured, we recharacterized the working plasmid BBa_K2890006 followed by iGEM’s standard measurement protocols. According to our study, it is proven that the biobrick BBa_K2890006 is available and reproducible, and functioning as a machine which could detect and degrade formaldehyde. Moreover, we hope that the supplementing experimental data from us can be a meaningful reference for others.