Team:Paris Bettencourt/Notebook/Phage Sensor/Sunday 25th August.html


Phage Sensor

Sunday 25th August

Gel of Gradient PCR, Liquid Cultures, Ligation M13 + RFP, Ligation SPCR5, SPCR7, Electrocompetent cells, Gibson Assembly, Transformation (Gibson)and Transformation (Gibson, Ligations.

Gel of Gradient PCR
1%, 100V, 20min

Liquid Cultures
NEB Turbo


Ligation M13 + RFP
0.5ul Vector (M13)
2.6ul Insert (RFP)
5.4ul H20
1.0ul T4 buffer
0.5ul T4 Ligase

Ligation SPCR5, SPCR7
1.0ul Vector (SPCR5)
1.5ul Insert (SPCR7)
6.0ul H20
1.0ul T4 buffer
0.5ul T4 Ligase

Incubate ~30min at 37 C

Electrocompetent cells
1) Start Culture
2) When the cells reach an OD600 of 0.2.
3) Harvest the cells.
When the cells reach an OD600 of between 0.6 and 0.8 (OD: 0,683)
Centrifuge at 4 °C for 10 min at 4000 rpm.
4) Wash and combine the cells.
Remove the supernatant.
Resuspend the cells in 25 ml of ice cold water
5) Wash the cells 2 more times.
Centrifuge at 4 °C for 10 min at 4000 rpm.
Resuspend in 50 ml of ice cold water.
Repeat. 6) Wash and concentrate the cells for electroporation.
Centrifuge at 4 °C for 10 min at 4000 rpm.
Resuspend in 1-2 ml of ice cold water.
We will use 200 ul of washed cells per transformation.

Gibson Assembly

Amount per Reaction
Positive Control**

PCR Fragment(s)
+ linearized vector
2-10 μl (0.02–0.5 pmols)*

Assembly Master
Mix (2X)
10 μl

Deionized H2O
XX μl

Total Volume
20 μl

Incubate samples in a thermocycler at 50°C for 15 minutes. After incubation, store the samples on ice or at -20°C for subsequent transformation
Note: Extended incubation up to 60 minutes may help to improve assembly efficiency in some cases (for further details see FAQ section).
Transform NEB 5-alpha Competent E. coli cells (provided with the kit) with 2 μl of the assembly reaction, following the transformation protocol.

Transformation (Gibson)
Thaw competent cells on ice.
Add 2 μl of the chilled assembly product to the competent cells. Mix gently by pipetting up and down or by flicking the tube 4–5 times. Do not vortex.
Place the mixture on ice for 30 minutes. Do not mix.
Heat shock at 42°C for 30 seconds. Do not mix.
Transfer tubes to ice for 2 minutes.
Add 950 μl of room-temperature SOC media to the tube.
Incubate the tube at 37°C for 60 minutes. Shake vigorously (250 rpm) or rotate.
Warm selection plates to 37°C.
Spread 100 μl of the cells onto the selection plates. Use Amp plates for positive control sample.
Incubate overnight at 37°C.

Transformation (Gibson, Ligations)
1) Prepare BD tubes with a pipette filled with LB at the interior of each tube (pipette supplied with the electroporation cuvette)

2) Test the purity of the electrocompetent cells.
Add 200 ul of washed cells to a cuvette.

3) Mix the cells and DNA in a cuvette.
200 ul of washed cells with 200 ng of PCR product.
Keep the cuvette on ice until just before the electroporation.

4) Preload a pipette with 1 ml of LB.

5) Pulse the cuvette with voltage.
Dry the electrodes with a kimwipe prior to loading.
Use the EC2 setting.

6) Listen for arcing.
A cracking sound means all the cells are dead.
Note the time constant: 5 is good, 5.8 is great.

7) Immediately recover the cells.
Add the 1 ml of preloaded LB and pipet up and down to mix.
Collect 1 ml of cells, some volume is lost in the cuvette.

8) Incubate 2 h at 37 °C with shaking.

9) Plate 100 ul of recovered cells on selective plates.
Use antibiotic appropriate to the part being integrated.
Let the other 900 ul rest overnight at room temperature.

10) Concentrate and plate the remaining cells
Spin down quickly and resuspend in 100 ul LB before plating.

Transformed cells should be incubated at 37 °C.
Colonies should appear 24-48 h after plating.