Team:NEU China B/Improve
BBa_k2824008:Lldr-T7-lldPRD operon promoter-GFP
The role of this part is to try to control the concentration of lactic acid on the LLDPRD promoter under the control of quorum sensingg. In the case of LLdr gene expression, the subsequent gene expression was initiated.
This part also is constructed based on the part lldRO1-plldR-lldRO2 (BBa_k82000) . lldRO1-plldR-lldRO2 part is a lactic acid regulated promoter that is open to gene transcription in the presence of lactic acid. Comparing with the T7-lldPRD operon promoter-GFP part, the improvement of this part is that the LLDR is added to part and placed under the control of two promoters respectively to form a double expression regulatory system. This comparison with the two plasmids working together is more convenient for testing the success of the system.
We can easily find that the Lldr-T7-lldPRD operon promoter-GFP part are in a higher level of expression comparing to the lldPRD operon promoter-GFP when the lactate concentration is lower than nearly 1.5m mol/L. Considering that the lactate concentration in yogurt is generally no more than 1m mol/L, the conclusion can given that the T7 promoter can enhance the signal intensity for our experiments.
BBa_k2824006:T7-lldPRD operon promoter-GFP
LLDPRD can sense the presence of lactic acid, in the absence of lactic acid, only a lower background level of expression, but in the presence of lactic acid can open expression, gene transcription. We added the GFP gene into the gene and used green fluorescence as a marker to recognize the presence of lactic acid. In addition, as a strong promoter, T7 can improve the expression level of the target gene.
This part is constructed based on the part lldRO1-plldR-lldRO2 (BBa_k82000) . lldRO1-plldR-lldRO2 part is a lactic acid regulated promoter that is open to gene transcription in the presence of lactic acid. We added a sequence of T 7 promoter and GFP fluorescent protein gene before and after this part Separately. It can effectively improve the expression of the target gene and detect whether the target gene is expressed or not. At the same time, it can accurately determine the amount of the target gene. This allows the overall work of our system to be reflected in digital form.
In the following figure, we compared the expression of lldPRD operon promoter-GFP and T7-lldPRD operon promoter-GFP. The T7 promoter could enhance gene expression when the concentration of lactic acid was less than 1 m mol/L. Considering that the lactate concentration in yogurt is generally no more than 1m mol/L, the conclusion can given that the T7 promoter can enhance the signal intensity for our experiments
