Team:PKU Beijing/Project/AND Gate 1/Inducible System Result
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[[Image:PKU_Lac_1.png|325px|left|thumb|Fig3. lac promoter induction curve.<br>The Bacteria is induced with 10^-9~10^-3 M IPTG, the fluorescence is measured by plate-reader]] | [[Image:PKU_Lac_1.png|325px|left|thumb|Fig3. lac promoter induction curve.<br>The Bacteria is induced with 10^-9~10^-3 M IPTG, the fluorescence is measured by plate-reader]] | ||
- | + | [[Image:PKU_lac_1.png|500px|right|thumb|Fig4. the JM109 colonies that contain low copy pLac-GFP plasmid. Center of the colonies turns green, while in the other area GFP expression is suppressed. It suggests that some E.coli lost their F plasmids]] | |
However, there is still another problem in this simplified system: the loss of F plasmid of JM109 may lead to activation of promoter pLac without induction. From the plate (without induction), we found that part(especially the central part) of a singal colony turned green, while they are supposed to stop express GFP in the presence of lacIq. A stronger evidence is the data from flowcytometry: The strength of GFP fluorescence obviously shows double peaks. All these suggest that some of the cell retains the F plasmid while the the others lost it. | However, there is still another problem in this simplified system: the loss of F plasmid of JM109 may lead to activation of promoter pLac without induction. From the plate (without induction), we found that part(especially the central part) of a singal colony turned green, while they are supposed to stop express GFP in the presence of lacIq. A stronger evidence is the data from flowcytometry: The strength of GFP fluorescence obviously shows double peaks. All these suggest that some of the cell retains the F plasmid while the the others lost it. | ||
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[[Image:PKU_lac_2.png|600px|center|thumb|Fig5a, b & c. The fluorescence was measured by flowcytometry to see the fluorescence of each cell in a population. <br>Fig5a illustrates that there are leaky cells and normal cells without induction. Fig4b shows the data from the cells induced by 10^-6M IPTG, and Fig4c show those induced by 10^-5M IPTG. Double peaks can be observed on both 4a and 4b, which means there are two groups of E.coli, but as the induction saturates, two peaks merge into one peak.]] | [[Image:PKU_lac_2.png|600px|center|thumb|Fig5a, b & c. The fluorescence was measured by flowcytometry to see the fluorescence of each cell in a population. <br>Fig5a illustrates that there are leaky cells and normal cells without induction. Fig4b shows the data from the cells induced by 10^-6M IPTG, and Fig4c show those induced by 10^-5M IPTG. Double peaks can be observed on both 4a and 4b, which means there are two groups of E.coli, but as the induction saturates, two peaks merge into one peak.]] |
Revision as of 12:34, 20 October 2009
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