Team:Evry/Notebook/Test

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Iron coli project

Week 1: 17th June - 23rd June

Tuesday, 19th June

As a start for the labwork, we first decided to make competent cells. We grew from glycerol samples three E. coli strains in 2 mL of LB medium.
The chemically competent strains chosen are as follows:

BL21
DH5α
TOP10


Protocol for pre-culture preparation

In a 15 mL tube, add 2 mL of LB medium and inoculate cells from glycerol

Thursday, 20th June


We started to make 200 mL of BL21 and DH5α E. coli strains and 400 mL of TOP10 to make competent cells.


Protocol for competent cells

First prepare the following solutions required to make competent cells:
Solution for 1M Cacl2:
Add 14,30g of CaCl2 into 100 ml desalted water

Solution for 0,1M Cacl2:
Add 50 mL of CaCl2 1M solution into 450 ml of desalted water

Solution for 0,1M Cacl2 + 15% glycerol:
Add 50 mL of CaCl2 1M solution and 75 mL of glycerol 100% into 450 ml of desalted water


For 200 ml LB medium, add 400 µL of strain sample.
Let the bacteria grow until it reaches an OD between 0,3 and 0,35.
Once it reached the right OD, put the medium on ice for 30 minutes to slow down growth.
Split the 200 mL into 4x50 mL tubes then centrifuge at 3000 rpm for 5 minutes at 4°C and suppress supernatant afterwards.
Resuspend the cells with 5 mL of Cacl2 at 0,1M for each 50 mL tube.
Again, put the medium on ice for 30 minutes.
Centrifuge at 3000 rpm for 5 minutes at 4°C then suppress supernatant.
Resuspend the cells with 1 mL of Cacl2 at 0,1M + 15% glycerol for each 50 mL tube.
Split the total 4 mL into 40 tubes containing each 100 µL of concentrated cell solution. This step should be executed fast enough and on ice.



Friday, 21st June


To check the quality of our work, each strain has been plated on LB medium with ampicillin, kanamycin or chloramphenicol in order to evaluate if it contaminated or not. Furthermore, to evaluate wether our strains are competent or not, we also transformed our bacteria with a pSB1A3 plasmid (red colonies) and plated them on LB medium with ampicillin only.

Protocol for transformation

For 100 µL of chemical competent cells, add 1 µL of plasmidic DNA.
Let 30 minutes on ice.
Let the cells at 42°C for exactly 50 seconds.
Let 5 minutes on ice.
Resuspend the cells with 1 mL of LB spread on a petri dish then let it at 37°C.

Week 2: 24th June - 30th June

Week 3: 1st July - 7th July

Week 4: 8th July - 14th July

Week 5: 15th July - 21st July

Week 6: 22nd July - 28th July

Week 7: 29th July - 4th August

Week 8: 5th August - 11th August

Week 9: 12th August - 18th August

Week 10: 19th August - 25th August

Week 11: 26th August - 1st September

Week 12: 2nd September - 8th September

Week 13: 9th September - 15th September

Week 14: 16th September - 22nd September

Week 15: 23rd September - 29th September

Week 16: 30th September - 6th October

Week 17: 7th October - 13th October

Week 18: 14th October - 20th October

Week 19: 21st October - 27th October

Week 20: 28th October - 3rd November