Team:TU Darmstadt/Protocols/Chemically competent cells

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== Bacterial transformation ==
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== Chemically competent cells ==
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The [[Bacterial_transformation | transformation]] of ''E. coli'' with plasmid DNA via [[Heatshock transformation]] requires chemical competent cells.
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The [https://2012.igem.org/Team:TU_Darmstadt/Protocols/Bacterial_transformation transformation] of ''E. coli'' with plasmid DNA via [https://2012.igem.org/Team:TU_Darmstadt/Protocols/Heat_Shock_Transformation heatshock transformation] requires chemically competent cells.
 +
 
== Materials ==
== Materials ==
=== Equipment ===
=== Equipment ===
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* ice cold 100mM CaCl<sub>2</sub>  
* ice cold 100mM CaCl<sub>2</sub>  
=== Procedure ===
=== Procedure ===
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# 2mL preculture ''E.coli'' in DYT-medium
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# Inoculate 2 mL of LB-Media with an E. coli colony and incubate at 37 °C overnight
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# incubate preculture overnight at 37°c
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# Inoculate 200 mL LB with the preculture
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# inoculate 200 mL with the preculture
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# Incubate at 37°C and 150 rpm until an OD<sub>600</sub> of 0.4-0.6 is reached
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# incubate at 37°C and 150 rpm till an OD<sub>600</sub> of 0.4 - 0.6 is reached
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# Incubate cells on ice for 15 min
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# incubate cells on ice for 15 min
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# Centrifuge the culture at 4°C and 3000 x g for 10 min (the following steps are carried out on ice)
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# centrifuge the culture at 4°C and 3000 x g for 10 min (the following steps are done on ice)
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# Resuspend cell pellet in 10mL ice cold 100 mM CaCl<sub>2</sub> (Do not vortex!)
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# resuspend cell pellet in 10mL ice cold 100 mM CaCl<sub>2</sub>
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# Incubate on ice for 1 hour
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# incubate on ice for 1 hour
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# Centrifuge the culture at 4°C and 3000 x g for 10 min
-
# centrifuge the culture at 4°C and 3000 x g for 10 min
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# Resuspend cell pellet in 10mL ice cold 100 mM CaCl<sub>2</sub>
-
# resuspend cell pellet in 10mL ice cold 100 mM CaCl<sub>2</sub>
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# Incubate on ice for 1 hour
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# incubate on ice for 1 hour
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# Centrifuge the culture at 4°C and 3000 x g for 5 min
-
# centrifuge the culture at 4°C and 3000 x g for 5 min
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# Resuspend cell pellet in 2mL ice cold 100 mM CaCl<sub>2</sub> and 15 % (v/v) glycerine
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# resuspend cell pellet in 2mL ice cold 100 mM CaCl<sub>2</sub> and 15 % (v/v) glycerine
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# Incubate on ice for 30 min
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# incubate on ice for 30 min
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# Aliquot the cells à 100µL
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# aliquot the cells à 100µL
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# Store at -80°C
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# store at -80°C
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 +
=== Solutions ===
 +
* CaCl<sub>2</sub>
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**5.55 g CaCl<sub>2</sub>
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**Add di H<sub>2</sub>O to 1 L
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**Sterilize by autoclaving
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 +
*Cryo solution
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** 0.278 g CaCl<sub>2</sub>
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** 10 ml glycerin
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** Add di H<sub>2</sub>O to 50 ml
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** Sterilize by autoclave
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== References ==
== References ==
* Mandel, M. and Higa, A.: Calcium-dependent bacteriophage DNA infection. J Mol Biol, 1970, 53, 159-162
* Mandel, M. and Higa, A.: Calcium-dependent bacteriophage DNA infection. J Mol Biol, 1970, 53, 159-162

Latest revision as of 21:12, 26 September 2012

Contents

Chemically competent cells

The transformation of E. coli with plasmid DNA via heatshock transformation requires chemically competent cells.

Materials

Equipment

  • -80°C freezer
  • Incubation shaker
  • Centrifuge (cooling cababilities required!)
  • photometer
  • Ice water bath

Chemicals & consumables

  • Ice and/or liquid nitrogen
  • Falcon tubes
  • dYT Medium (50 ml p.c.)
  • ice cold 100mM CaCl2

Procedure

  1. Inoculate 2 mL of LB-Media with an E. coli colony and incubate at 37 °C overnight
  2. Inoculate 200 mL LB with the preculture
  3. Incubate at 37°C and 150 rpm until an OD600 of 0.4-0.6 is reached
  4. Incubate cells on ice for 15 min
  5. Centrifuge the culture at 4°C and 3000 x g for 10 min (the following steps are carried out on ice)
  6. Resuspend cell pellet in 10mL ice cold 100 mM CaCl2 (Do not vortex!)
  7. Incubate on ice for 1 hour
  8. Centrifuge the culture at 4°C and 3000 x g for 10 min
  9. Resuspend cell pellet in 10mL ice cold 100 mM CaCl2
  10. Incubate on ice for 1 hour
  11. Centrifuge the culture at 4°C and 3000 x g for 5 min
  12. Resuspend cell pellet in 2mL ice cold 100 mM CaCl2 and 15 % (v/v) glycerine
  13. Incubate on ice for 30 min
  14. Aliquot the cells à 100µL
  15. Store at -80°C

Solutions

  • CaCl2
    • 5.55 g CaCl2
    • Add di H2O to 1 L
    • Sterilize by autoclaving
  • Cryo solution
    • 0.278 g CaCl2
    • 10 ml glycerin
    • Add di H2O to 50 ml
    • Sterilize by autoclave

References

  • Mandel, M. and Higa, A.: Calcium-dependent bacteriophage DNA infection. J Mol Biol, 1970, 53, 159-162
Retrieved from "http://2012.igem.org/Team:TU_Darmstadt/Protocols/Chemically_competent_cells"