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==Protocols== | ==Protocols== | ||
− | === | + | ===Heat shock competent cells preparation=== |
− | + | '''Day 1''' Inoculate cells in 3.5mL LB medium. | |
− | + | Incubate at 37°C overnight. | |
− | + | ||
+ | '''Day 2''' Measure culture OD at 600nm. Dilute cells in 250mL of LB medium so OD equals to 0.12. | ||
+ | Incubate overnight at 20°C and 180rpm. | ||
+ | |||
+ | '''Day 3''' Measure culture OD at 600nm and dilute to obtain OD<sub>600nm</sub>=0.6. | ||
+ | Cells must be kept at 4°C during all following steps. | ||
+ | Put on ice for 10min and centrifuge for 10min at 3000rpm and 4°C. | ||
+ | Discard supernatant and resuspend cells in 80mL of fresh TB buffer. | ||
+ | Keep on ice for 10min and centrifuge for 10min at 3000rpm and 4°C. | ||
+ | Discard supernatant again and resuspend cells in 20mL of fresh TB buffer with 7% of DMSO. | ||
+ | Keep on ice for 10min. | ||
+ | Aliquot cells and freeze with liquid nitrogen. | ||
+ | Keep at -80°C. | ||
+ | |||
+ | '''TB buffer recipe''' | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |HEPES | ||
+ | |10mM | ||
+ | |- | ||
+ | |MnCl<sub>2</sub> | ||
+ | |55mM | ||
+ | |- | ||
+ | |CaCl<sub>2</sub> | ||
+ | |15mM | ||
+ | |- | ||
+ | |KCl | ||
+ | |250mM | ||
+ | |- | ||
+ | |KOH | ||
+ | | | ||
+ | |} | ||
+ | Dissolve HEPES, CaCl<sub>2</sub> and KCl in water. Adjust pH to 6.7 with KOH. Add MnCl<sub>2</sub>. Filter to sterilize and keep at 4°C. | ||
+ | |||
+ | ===Heat shock competent cells tranformation=== | ||
+ | |||
+ | |||
+ | |||
+ | ===Electro-competent cells preparation=== | ||
+ | '''Day 1''' Inoculate 15mL of LB with 200µL of an overnight cell culture. | ||
+ | Incubate at 37°C and 180rpm until OD<sub>600nm</sub> reaches 0.6. | ||
+ | Centrifuge cells for 10 minutes at 4000rpm. | ||
+ | Wash twice with 10mL of 10% glycerol. | ||
+ | Put cells in 200µL of 10% glycerol and use for electroporation. |
Revision as of 15:27, 6 July 2016