Protocols

Agarose gel

1. Weigh 0,3g of agarose.
2. Add 30 mL of TAE 1X.
3. Heat up until the solution is homogeneous, avoiding boiling. If it boils, move away from the heat until it “calms down” and put it back on the heat until the agarose is completely dissolved.
4. While heating, prepare the bed in which the gel will polymerize. Make sure that it is well balanced and tight, and that the “comb” is well placed.
5. When homogeneous, add 2 µL of SYBR SAFE DNA Gel Stain to the solution and mix well.
6. Pour the solution into the bed and clear all its bubbles with a tip. Put a piece of paper on top of it and let it polymerize.
7. Mix the samples with loading dye in a 5:1 ratio. Put the samples into the wells, as well as 4 µL of molecular weight marker into the first well.

Note: For big gels use 0,7 g of agarose, 70 mL of TAE 1x and 3 µL of SYBR SAFE Gel Stain.


LB medium (1L liquid)

• 10 g tryptone
• 10 g NaCl
• 5 g yeast extract
• Water

LB medium (solid, 1L = 50 dishes)

• 15 g agar agar
• 10 g tryptone
• 10 g NaCl
• 5 g yeast extract
• Water

For selective medium, suplement with antibiotic as appropiate (kanamycin 50 µg/ mL and 100 µg/mL for chloramphenicol or ampicillin ).


Electrocompetent cells

1. Divide the ON culture in 50 mL falcon tubes (we always used ''E. coli'' TOP10).
2. Centrifuge 8000 rpm x 10 min.
3. Discard supernatant.
4. Resuspend everything with water in two falcons.
5. Centrifuge again.
6. Discard supernatant and resuspend with water. Wash with water two more times.
7. Centrifuge again.
8. Discard supernatant.
9. Resuspend with glycerol with water. Glycerol 10 %.
10. Centrifugue.
11. Repeat steps 8-10.
12. Discard supernatant and divide what is left in eppendorfs.

CAUTION: Everything must be done on ice (0-3°C) (reactants, centrifuge, transport, containers).


Genome extraction

For bacterial genome extraction we used Easy DNA Kit, Invitrogen according to manufacturer's instructions.


Plasmids extraction

For bacterial plasmid extraction we used GenElute Plasmid Miniprep Kit, Sigma Aldrich according to manufacturer's instructions.


Transformation by electroporation

1. Mix 40 µL of electrocompetent cells with 4 µL of DNA (we used iGEM BioBricks resuspended in 20 µL of miliQ water ).
2. Incube the cuvettes for electroporation on ice and the above mix as well.
3. Electroporate into the cuvette.
4. Add (as quick as possible) 200 µL of LB medium.
5. Incubate for 30 min at 37 °C .
6. Plate bacteria over sumplemented LB medium.
7. Incubate at 37 °C, 24 h.
8. Use isolated colonies to check the correct insertion.

Biobrick Assembly

The digestion and ligation of the BioBricks were carried out using the Biobrick Assembly Kit, New England Biolabs Inc. The protocols for both procedures can be found here.