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Team:OUC-China/Project Result
From 2014.igem.org
mini plasmid & double plasmid system
mini plasmid
We get the oriT region of plasmid RP4 by means of PCR, and ligate it with the reporter gene BBa_J04450, then a non-self-controllable conjugated part is constructed.
In the meantime, we ligate BBa_J04450 with BBa_J01003 to test the conjugated ability of BBa_J01003.
Deactivate the OriTRP4
We attempt to deactivate the OriT of plasmid RP4 by homologous recombination, unfortunately, the first experiment failed. And we have no time to do experiment before the deadline.But, it is theoretical to deactivate the OriT. We will continue our experiment after the competition.
We make two plasmids enter in E.coli HB101, one is plasmid RP4 (the oriT site was deactivated) and another is mini plasmid carrying oriTRP4-RFP or oriTR-RFP. Firstly, oriTRP4-RFP and oriTR-RFP transfer in competent cells HB101 (by inducing artificially, from Qiu Zhigang) respectively. Secondly, by means of conjugation, we make the plasmid RP4 get in HB101 which mentioned above and already has a mini plasmid. Thirdly, we screen cells with two plasmids by chloramphenicol and kanamycin. Eventually, we acquire HB101 strains carrying two plasmids (RP4, oriTRP4-RFP or oriTR-RFP).
Conjugation
Test1. Conjugation between E.coli HB101 and Top10
We did conjugation experiment between HB101 and Top10 to test the conjugation ability of OriTRP4 (BBa_K1439000). We got a special strain from other lab which is sensitive to Streptomycin, while Top10 has streptomycin resistance. In order to test BBa_K1439000 better, we ligated OriTRP4 with the report gene RFP. After conjugation, we picked the red colonies by LB medium with resistance.
We designed a orthogonal experiment, it is showed in the table. The first column shows the strains used in coating, and the first row shows the antibiotics added in medium. Besides, the table shows the result ideally. The second row proves that HB101, plasmid RP4 and the backbone pSB1C3 don’t contain streptomycin resistant gene. The third row proves that Top10 is sensitive to chloramphenicol. And the forth row proves that Top10 can receive the mini plasmid after conjugation.
Conjugation between E.coli HB101 and Top10
| Conjugation (HB101 and Top10 mixed system) | Top10(no plasmid) | HB101(double plasmids system) | |
|---|---|---|---|
| Streptomycin | White colony | White colony | No colony |
| chloramphenicol | Red colony | No colony | Red colony |
| chloramphenicol & streptomycin | Red colony | No colony | No colony |
Table.1 We constructed a new part BBa_K1439001 to test the conjugation result. BBa_K1439001 is used in conjugation experiments below.
Result
Figure 1.
Figure 2.
Figure 1. is the result of conjugation experiment, but it doesn’t correspond to Table.1. Red fluorescent proteins are not expressed. So we picked the conjugated colonies and cultured. After culturing hours, we extracted the plasmid and sequenced. (Figure 2.)Finally, we verified that BBa_K1439000 could transfer in recipient cells with the help of plasmid RP4.
Test2. Conjugation between E.coil HB101 and Vibrio harveyi
We also test the conjugation ability of double plasmids system between E.coil HB101 and Vibrio harveyi.
Result
The Vibrio harveyi is used as recipient cell and can be screened by Thiosulfate citrate bile salts sucrose agar culture medium (TCBS) with chloramphenicol.
At the same time we test the BBa_J01003 the conjugation ability by the same way.
Conjugation between E.coli HB101 and Top10
| Streptomycin | chloramphenicol | chloramphenicol & streptomycin | |
|---|---|---|---|
| Conjugation (HB101 and Top10 mixed system) | White colony | Red colony | Red colony |
| Top10(no plasmid) | White colony | No colony | No colony |
| HB101(double plasmids system) | No colony | Red colony | No colony |
table2.
Table.2 We constructed a new part BBa_K1439002 which linked BBa_J01003 with the reporter gene BBa_J04450 to test the conjugation ability of BBa_J01003.
Result
