Team:Team:Imperial College London/Wetlab/Protocols/Cellculture/CC9
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{{Imperial/09/TemplateTop}} | {{Imperial/09/TemplateTop}} | ||
+ | {{Imperial/09/Tabs/Main/Wetlab/Protocols}} | ||
=Preparation of XL1-Blue Electrocompetent Cells= | =Preparation of XL1-Blue Electrocompetent Cells= | ||
===Aims=== | ===Aims=== | ||
- | Preparation of ''E. coli'' cells for the cloning of Biobricks and construct | + | Preparation of ''E. coli'' cells for the cloning of Biobricks and construct assembly. |
+ | {{Imperial/09/Division}} | ||
===Equipment=== | ===Equipment=== | ||
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*Stripettes | *Stripettes | ||
- | + | {{Imperial/09/Division}} | |
===Reagents=== | ===Reagents=== | ||
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*Dry ice bath | *Dry ice bath | ||
- | + | {{Imperial/09/Division}} | |
- | + | =Protocol= | |
<b>Keep everything cold where possible - if using a carbon fibre rotor, you may want to put it in a cold room after innoculation.</b> | <b>Keep everything cold where possible - if using a carbon fibre rotor, you may want to put it in a cold room after innoculation.</b> | ||
Line 45: | Line 47: | ||
#Test OD immediately after innoculating the litre flask. | #Test OD immediately after innoculating the litre flask. | ||
#Grow cells while mixing at at least 225rpm until the culture reaches an OD<sub>600nm</sub> of 0.5-0.6 (1.6-1.9×10<sup>8</sup>cells/ml) | #Grow cells while mixing at at least 225rpm until the culture reaches an OD<sub>600nm</sub> of 0.5-0.6 (1.6-1.9×10<sup>8</sup>cells/ml) | ||
- | + | ##<i>First doubling may take 1 hour but doublings after that should be every 20-30 mins, so check often!</i> | |
#When OD is 0.5-0.6, transfer the culture to 2 sterile 500mL centrifugation bottles and cool on ice for a few minutes | #When OD is 0.5-0.6, transfer the culture to 2 sterile 500mL centrifugation bottles and cool on ice for a few minutes | ||
#Pellet cells in a centrifuge at 4,000g for 15 mins | #Pellet cells in a centrifuge at 4,000g for 15 mins | ||
#Quickly but carefully pour off the supernatant then carefully resuspend the cells in 10mL of ice cold ddH<sub>2</sub>O | #Quickly but carefully pour off the supernatant then carefully resuspend the cells in 10mL of ice cold ddH<sub>2</sub>O | ||
#Fill both tubes to about 350mL with ice cold ddH<sub>2</sub>O | #Fill both tubes to about 350mL with ice cold ddH<sub>2</sub>O | ||
- | + | ##<i>Make sure the pellet is fully resuspended!</i> | |
#Repellet the cells (as before) and again discard the supernatant | #Repellet the cells (as before) and again discard the supernatant | ||
#Resuspend cells again in 10mL of ddH<sub>2</sub>O, then fill both tubes up to about 150mL with ice cold ddH<sub>2</sub>O | #Resuspend cells again in 10mL of ddH<sub>2</sub>O, then fill both tubes up to about 150mL with ice cold ddH<sub>2</sub>O | ||
#Repellet the cells (as before) | #Repellet the cells (as before) | ||
- | + | ##<i>While repelleting, fill the dry ice bath and set up Eppendorf tubes (approximately 50) in a rack in the dry ice bath.</i> | |
#Pour off the supernatant and resuspend the cells in 20mL of 10% glycerol (resuspend one pellet then transfer the solution to the other bottle and resuspend the second pellet) | #Pour off the supernatant and resuspend the cells in 20mL of 10% glycerol (resuspend one pellet then transfer the solution to the other bottle and resuspend the second pellet) | ||
#Transfer the cells and glycerol solution to a sterile 50mL centrifuge tube and pellet for 15 mins at 4,000g | #Transfer the cells and glycerol solution to a sterile 50mL centrifuge tube and pellet for 15 mins at 4,000g | ||
#Pour off supernatant and resuspend pellet in 2mL of 10% glycerol | #Pour off supernatant and resuspend pellet in 2mL of 10% glycerol | ||
#Pipette 50μL aliquots into the Eppendorfs in the dry ice bath | #Pipette 50μL aliquots into the Eppendorfs in the dry ice bath | ||
- | + | ##<i>Freeze on dry ice.</i> | |
- | + | ##<i>Depending on pipetting accuracy, between 50 and 60 aliquots should be made.</i> | |
- | + | ##<i>Using a repeating pipette makes this process much faster and reduces risk of contamination.</i> | |
#Store at -70°C | #Store at -70°C | ||
Latest revision as of 13:10, 2 October 2009
Contents |
Preparation of XL1-Blue Electrocompetent Cells
Aims
Preparation of E. coli cells for the cloning of Biobricks and construct assembly.
Equipment
- 4,000RPM Centrifuge
- Sterile Centrifugation bottles
- 50ml Tubes
- Large Flasks
- Eppendorf Tubes
- P200 Pipette
- Stripettes
Reagents
- 1 litre of LB medium
- Tetracycline
- 1-2 litres of autoclaved and chilled ddH2O
- 10% glycerol in ddH2O, autoclaved and chilled
- Dry ice bath
Protocol
Keep everything cold where possible - if using a carbon fibre rotor, you may want to put it in a cold room after innoculation.
Set aside an afternoon for this, starting the culture in the morning
Frequently check the culture whilst growing.
- Grow up a culture of E. coli XL1-blue cells overnight
- Add 40mL of overnight culture to 1 litre of LB medium (containing 20μg/ml Tetracycline)
- Test OD immediately after innoculating the litre flask.
- Grow cells while mixing at at least 225rpm until the culture reaches an OD600nm of 0.5-0.6 (1.6-1.9×108cells/ml)
- First doubling may take 1 hour but doublings after that should be every 20-30 mins, so check often!
- When OD is 0.5-0.6, transfer the culture to 2 sterile 500mL centrifugation bottles and cool on ice for a few minutes
- Pellet cells in a centrifuge at 4,000g for 15 mins
- Quickly but carefully pour off the supernatant then carefully resuspend the cells in 10mL of ice cold ddH2O
- Fill both tubes to about 350mL with ice cold ddH2O
- Make sure the pellet is fully resuspended!
- Repellet the cells (as before) and again discard the supernatant
- Resuspend cells again in 10mL of ddH2O, then fill both tubes up to about 150mL with ice cold ddH2O
- Repellet the cells (as before)
- While repelleting, fill the dry ice bath and set up Eppendorf tubes (approximately 50) in a rack in the dry ice bath.
- Pour off the supernatant and resuspend the cells in 20mL of 10% glycerol (resuspend one pellet then transfer the solution to the other bottle and resuspend the second pellet)
- Transfer the cells and glycerol solution to a sterile 50mL centrifuge tube and pellet for 15 mins at 4,000g
- Pour off supernatant and resuspend pellet in 2mL of 10% glycerol
- Pipette 50μL aliquots into the Eppendorfs in the dry ice bath
- Freeze on dry ice.
- Depending on pipetting accuracy, between 50 and 60 aliquots should be made.
- Using a repeating pipette makes this process much faster and reduces risk of contamination.
- Store at -70°C