Team:Paris Liliane Bettencourt/Project/Memo-cell/Results
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<img src="https://static.igem.org/mediawiki/2010/5/5c/Integration_results-01.jpg" width=70%> | <img src="https://static.igem.org/mediawiki/2010/5/5c/Integration_results-01.jpg" width=70%> | ||
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+ | <img src="https://static.igem.org/mediawiki/2010/9/92/Excision.PNG" width=70%> | ||
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+ | To determine the efficiency of excission with the different arms we decided to | ||
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+ | use a Kan Lacz counter selection system. We took culture of cells where one of | ||
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+ | the third mutated transposon had been integrated via recombination of attP and | ||
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+ | attB site (integrase Lambda). This cells have been transform with a plasmid | ||
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+ | carrying the both gene Int and Xis of the Tn916 under the control of inducible | ||
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+ | Pbad promoter. From an overnigth culture, dilution has been done and induction at | ||
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+ | the beginning of exponential phase (O.D 0.2) with Arabinose at final | ||
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+ | concentration of 0.2%. Every two hours, we took one sample of each culture and | ||
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+ | put them in 2% of glucose to inhibit the Pbad promoter. Then during one hour the | ||
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+ | sample is kept at 37°C to dilute protein of the transposase. Like this we | ||
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+ | decrease the probability to have event of excision between the sampling and | ||
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+ | plating. To permit counting of colonies several dilution where plated in glucose | ||
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+ | 1% and then replicate on plate with Kanamycine. Colonies which have excise will | ||
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+ | not grow in Kanamycine. The excision efficiency correspond to 1-(unexcised | ||
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+ | CFU/Total CFU) number of cells Kanamycine resistante (not excissed) over total | ||
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+ | number of cells). | ||
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+ | What we observe is that the Wild type and Lambda arms of the Tn916 permit an | ||
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+ | excision of 100% after 2h of induction whereas the HK arms have an efficiency of | ||
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+ | 55% after 30h of induction. The results for wild type are consistent with the | ||
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+ | bibliography exept that the maximum efficiency is rise faster in our system. | ||
+ | Errrors bars indicate the standard deviation from two independent trials. | ||
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Revision as of 23:52, 27 October 2010