"
Team:Fudan-Shanghai/Project
From 2011.igem.org
|
|
Detail:The project “E.tree” is consisted of two genetically modified E.coli: E. trunk and E.leaf.E.trunk detects nitrates in the medium; if KNO3 is present, the first circuit is activated, RhlI produces the AHL (C4-homoserine lactone) and TetR is synthesized to block the second pathway. If the medium lacks KNO3, the first pathway is off while the second pathway is activated and LasI produces an AHL autoinducer (3OC12-homoserine lactone). E.leaf changes color corresponding to the signal molecules released by E.trunk. RhlR synthesized in E.leaf binds to the RhlI-directed signal, and the complex then interact with the pRhl promoter and yellow pigment is produced. This circuit also encodes RhlI, which multiple the circuit, so that all E.leaf would turn yellow. Similarly, if E.trunk releases 3OC12-homoserine lactone, which is encodes by LasI, all “leaves” would turn green. |
 |
Part I: E.Tree
|
|
Detail:Our project was designed to show the quorum sensing system between bacterias in the background story of "dinner service". To construct our pathway, we chose J23112 as promoter, using AHL and aiiA as the sensing materials with the reporter of RFP and YFP.Two circumstances were constructed to represent the"customer" and the "chef".The hungry "customer" express luxI to catalyze the synthesis of AHL, with the red fluorescent as a signal. AHL binds to the luxr part of the"chef" and stimulates the right hand lux promoter. The part BBa_K091109 works to generate luxS, a synthase that produces DPD and forms the AI-2 signaling molecule and express YFP to show yellow fluorescent. With the stimulating signal of "chef", which means the "dinner", the "customer " is satisfied and the promoter J23112 starts to express aiia to inhibite the AHL signal and "chef" response. The fluorescent disappears and the process is stoped |
 |
 |
|
|
|
Detail:In the project of neon lights, we intended to have E.coli engineered for emitting one color of fluorescence during exponential phase and another color during stationary phase, so that it is convenient to identify the phase and may also be utilized for other purposes. To achieve this goal, we chose BBa_J45992, a stationary phase promoter, and BBa_J45996, only active during exponential phase. Then we tried to produce different luciferases under the control of the promoters. Parts of various luciferases have been obtained by the team of Cambridge in 2010, for example, BBa_K325210, BBa_K325229, etc. System of degradation, such as ClpXP, can be used to optimize the project by degrading the previous luciferase when the latter is being produced, to make the latter color purer and the process of color changing faster. In addition, the fluctuation of the lusiferase activity due to the growth should be taken into consideration. |
 |
