Team:XMU-China/Data

How our devices work

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Figure 1: The synthesis of LuxR protein and the signalling molecule N-acyl-homoserine lactone (AHL) is induced by adding Isopropyl β-D-1-thiogalactopyranoside (IPTG). The AHL accumulates in the experimental medium and inside the cells as the cell density increases. At sufficiently high concentrations, it binds and activates the LuxR transcriptional regulator, which in turn induces the expression of a killer gene ccdB under the control of a promoter lux pR. Sufficiently high levels of the killer protein cause cell death. This circuit programmes a bacterial population to maintain a cell density that is lower than the limits imposed by the environment.

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Figure 2:

Data for favorite new parts

[BBa_K658003] http://partsregistry.org/wiki/index.php?title=Part:BBa_K658003 --a bacteria population-control device with RBS0.6 driven by lacl+pL

The device is designed to build a programmed bacterial death circuit.Based on the device,a series of bacteria population-control devices (BBa_K658001,BBa_K658004,BBa_K658005) are designed using RBSs of different strength in the killer protein producer. Also, we have designed a series of population-control devices(BBa_K658010,BBa_K658011,BBa_K658012) by mutagenesis at positition 3,5and 3/5 of lux pR.

A comparison in performance of all the population-control devices can be found in the experience page.

[BBa_K658005]http://partsregistry.org/wiki/index.php?title=Part:BBa_K658005 --a bacteria population-control device with RBS0.07 driven by lacl+pL

The device is designed to build a programmed bacterial death circuit. The cell growth curve of BL21 and BL21 with the programmed bacterial denth circuit can be found in the [experience] page, which indicates that this device has the ability to maintain cell density of the bacteria population at a relatively low value compared with bacteria without this circuit and extends the stable stage.

[BBa_K658016] http://partsregistry.org/wiki/index.php?title=Part:BBa_K658016 --LuxI->LuxR->lux pR->GFP

This part is designed to test the strength of promoters lux pR(BBa_R0062) and its 3 mutants lux pR-3 (BBa_K658006), lux pR-5(BBa_K658007), lux pR-3/5(BBa_K658008) in our project.Based on the device, a series of devices(BBa_K658017, BBa_658018, BBa_658019)are designed by mutagenesis at positition 3,5and 3/5 of lux pR. A comparison in performance of the devices can be found in the experience page.

Data for pre-exsiting parts

Experience:[BBa_F2622]http://partsregistry.org/Part:BBa_F2622:Experience --3OC6HSL Receiver Device controlled by PLlac 0-1

The expression test is conducted to show thatthe biobrick can be expressed in BL21 in the presence of IPTG.

Experience:[BBa_K137018]http://partsregistry.org/Part:BBa_K137018:Experience -- luxr->GFP

Different concentration of AHL lead to distinct expression levels of the gfp gene.

Data for improved parts

Experience:[BBa_R0062]http://partsregistry.org/Part:BBa_R0062:Experience

Parts involved:

[BBa_K658006]http://partsregistry.org/Part:BBa_K658006 --position 3 mutated promoter lux pR-3 (luxR & HSL regulated)

[BBa_K658007]http://partsregistry.org/Part:BBa_K658007 --position 5 mutated promoter lux pR-5 (luxR & HSL regulated)

[BBa_K658008]http://partsregistry.org/Part:BBa_K658008 --position 3&5 mutated promoter lux pR-3/5 (luxR & HSL regulated)

By mutagenesis at positition 3,5and 3/5 of lux pR, we obtained the new biobrick BBa_K658007, BBa_K658008,BBa_K658009. The mutants demostrate different strength in binding Lux R/AHL complex, providing a variety of threshold value of lux pR.