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<li>Place cultures on ice for 15 minutes. </li> | <li>Place cultures on ice for 15 minutes. </li> | ||
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− | <p><i>All subsequent steps should be carried out at 4°C.<br />Cells should be kept on ice wherever possible.</i></p> | + | <p style="padding-left:5px;"><i>All subsequent steps should be carried out at 4°C.<br />Cells should be kept on ice wherever possible.</i></p> |
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<li>Pour each 250mL culture into pre-chilled 500mL (or 1000mL) Falcon tubes.</li> | <li>Pour each 250mL culture into pre-chilled 500mL (or 1000mL) Falcon tubes.</li> |
Revision as of 21:55, 24 September 2016
Medium and Buffers
- Prepare the solution by mixing the ingredients stated above.
- Sterilize in an autoclave before using it to prepare the SOC medium.
- Prepare the solution by mixing the ingredients stated above.
- Sterilize in an autoclave.
*Source from 2015 iGEM Exeter
For nucleic acids DNA/RNA separation
- TAE buffer (Tris-acetate-EDTA)
- TBE buffer (Tris-borate-EDTA)
- LAB buffer (Lithium-acetate-borate)
- Prepare the solution by mixing the ingredients stated above.
If not using pre-mixed LB agar powder, prepare the materials as below:
- In a 1L Erlenmeyer flask, swirl and mix the solution.
- Cover the top of the flask with a lid/aluminum foil and label with autoclave tape.
- Autoclave the liquid setting for 20 minutes or according to your autoclave's specifications.
- After removing the solution from the autoclave, allow the agar solution to cool to 55°C in an oven or water bath.
- When pouring the LB agar into plates, keep the bench area sterile by working near a flame or Bunsen burner. Alternatively, prepare the plates in a vacuum hood.
- Add the appropriate amount of desired antibiotic (refer the table below) to the solution and swirl to mix.
- Pour approximately 20mL of LB agar per 10cm polystyrene Petri dish.
- Place the lids on the plates and allow them to cool for until the agar is solidified.
- Label the bottom of plates with antibiotic and date before storing in plastic bags or sealed with Parafilm at 4°C.
Table source from New England Biolabs
Additional note:
- Antibiotic carbenicillin can be substituted for ampicillin in antibiotic selection plates [1].
If not using pre-mixed LB broth powder, prepare the materials as below:
- Prepare the solution by mixing the ingredients stated above.
- Sterilize in an autoclave.
- Prepare the solution by mixing the ingredients stated above.
- Sterilize in an autoclave before using it to prepare SOC medium.
Additional notes
- Some formulations of SOB use 10 mM MgCl2 and 10 mM MgSO4 instead of 20mM MgSO4.
- SOB medium is also available dry pre-mixed from Difco, 0443-17
- Adjust to pH 7.5 prior to use. This requires approximately 25mL of 1M NaOH per liter.
Source from OpenWetWare
- Prepare the solution by mixing the ingredients stated above.
*Source from OpenWetWare
- Prepare the solution by mixing the ingredients stated above.
- Filter sterilize using a 0.22 μm filter.
- Store at 4°C or -20°C.
*Source from OpenWetWare: TSS
Transformation
Ingredients:
Before starting the procedure, be sure to:
- Pre-chill centrifuge and cool rotor to 4°C
- Pre-chill 1L of 10% (w/v) glycerol solution on ice
- Pre-chill 500mL/1000mL Falcon tubes on ice
During the procedure:
Work under flame at all times.
- Grow a 5mL overnight culture of cells in LB media.
- In the morning, dilute this culture by at least 1/100 into a 50mL of fresh LB media in a 200mL conical flask.
- Incubate them at 37°C.
- Monitor growth of the cells every 30 minutes by measuring OD at 600nm (OD600) by filling up 750 µL of culture into cuvette. Use LB medium as blank.
- Once the cells are ready at OD600 = 0.4-0.6, harvest the cells to prepare for electroporation.
- Place cultures on ice for 15 minutes.
- Pour each 250mL culture into pre-chilled 500mL (or 1000mL) Falcon tubes.
- Centrifuge at 5000rpm for 10 minutes.
- Pour off the supernatant and aspirate any residual broth.
- Add 250 mL of pre-chilled 10% (w/v) glycerol to each of the centrifuge bottles and completely suspend the cells by pipetting the solution up and down.
- Centrifuge at 5000rpm for 10 minutes.
- Pour off the supernatant.
- Completely suspend the cells in 250mL glycerol and re-centrifuge at 5000rpm for 10 minutes.
- Pour off the supernatant and suspend the cells in the residual glycerol by pipetting up and down.
- At this point you can electroporate or freeze the cells away. To freeze, add 100µL of the culture to microcentrifuge tubes on ice.
- Once you have used all of the culture, transfer the tubes to dry ice for 10 minutes.
- Once the cultures are frozen, transfer them to a -80°C freezer. The cultures should be good for more than 6 months.
All subsequent steps should be carried out at 4°C.
Cells should be kept on ice wherever possible.
Ingredients: