Difference between revisions of "Part:BBa K3408008"

Revision as of 12:03, 20 October 2020

P_nar-B0034-CⅠ-B0015-P_CⅠ-B0034-GFP-B0015

Used P_nar(BBa_K3408000), RBS(BBa_B0034), optimized CⅠ(BBa_K3408004), terminator(BBa_B0015), P_CⅠ(BBa_R0051), RBS(BBa_B0034) and GFP(BBa_E0040) to express GFP when PCⅠ was activated. When our Bacillus subtilis was in an aerobic environment, P_nar was suppressed without FNR and no CⅠ protein could be expressed so that P_CⅠ could be activated and we could see GFP expressed. But when our Bacillus subtilis was in an anerobic environment, CⅠ protein could be expressed to suppress P_CⅠ and we couldn't see GFP anymore.

1. Experimental methods

1.1.Construction of the expression vector

The pWB980-DB is digested with enzyme EcoRI and PstI. The target fragment of the promoter, RBS, gene of phytase and terminator of this device are synthesized by the biotechnology company with 6×His tags added. Add EcoRI and PstI restriction sites to both ends of the target fragment respectively. Connect the target fragment to the plasmid vector fragment to construct the recombinant expression vector pWB980-DB-P_nar-CⅠ-P_CⅠ-GFP.

Plasmid profile

Fig.1. The expression vector of device P_nar- CⅠ-PCⅠ-GFP

1.2.Construction and screening of recombinant engineered bacteria

Using B. subtilis WB800N as the expression host, the secretion expression vector pWB980-DB was transformed by electro-transformation. Inoculate them on LB solid medium coated with 10μg/mL kanamycin, and incubate them overnight at 37°C. Send transformants to biotechnology company for sequencing.

1.3 Characterization experiment

Take 2 bottles of 50ml LB liquid medium with 10μg/mL kanamycin, and inoculate the same amount of recombinant engineered bacteria.

①Culture engineered bacteria which have been transformed successfully for 6 hours, the test group is cultured in an anaerobic environment, and the negative control group is cultured in an aerobic environment.

②Use the microplate reader to observe the presence of fluorescence in the test group and the control group at 0 min, 10 min, 20 min, 30 min, 40 min, 60 min, 80 min, and 120 min.

2.Expected results

The test group: the fluorescence intensity gradually decreases

The control group: the fluorescence intensity remains unchanged

Fig.2. Expected results: changes of fluorescence intensity under an anaerobic induced environment over time.

These results are predicted because of the lack of experiment for the COVID-19.

Sequence and Features