Transformation of E. coli competent cells (heat shock)

Goal

Protocol

1. Prepare ice containers.



SAFETY AND USEFUL RECOMMANDATION
To prevent the ice conrainer from falling off the workbench, it is recommended to place it away from edges. In addition, it is better to put eppendorfs in a special rack. It is important to know where manipulations will be achieved in order to apprehend the possible risks.



2. Thaw TSS E. coli competent cells (from the freezer) on ice.



SAFETY AND USEFUL RECOMMANDATION
Using the -80°C freezer requires to wear special gloves which protect against frostbite. Moreover ice melts, therefore it is also important to be careful not to place the iced object near electric devices. There is a risk of electrocution.



3. Add DNA, pipette gently to mix (1 µL of prepped plasmid is more than enough).



SAFETY AND USEFUL RECOMMANDATION
During this step, cells are manipulated. It is thus necessary to work in the sterile environment provided by the flow hood.



4. Let sit for 30 minutes on ice.


5. Set the heating block at 42°C.



SAFETY AND USEFUL RECOMMANDATION

It is important to know how a device works before using it. The heating block takes a long time before reaching a defined temperature. Therefore, it is recommended to switch it on a while before you need it. It is possible to accelerate the temperature increase by setting the device to a higher temperature than the one required. Of course it has to be set to 42°C. In case the protocol requires a higher, the users must be careful of the electric cables. They must not touch the hot spot of the device. Users must also not forget to stop the device once it is not needed any further.



6. Incubate cells for 30 seconds at 42°C.



SAFETY AND USEFUL RECOMMANDATION
Make sure that the eppendorfs are closed.



7. Incubate cells on ice for 2 min.


8. Add 1 mL of LB medium at room temperature.



SAFETY AND USEFUL RECOMMANDATION
This has to be done in a sterile area.



9. Incubate for 1 hour at 37°C on shaker.


10. Spread 100-300 µL onto a plate complemented with appropriate antibiotic.



SAFETY AND USEFUL RECOMMANDATION
This has to be done in a sterile environment.



11. Grow overnight at 37°C.



SAFETY AND USEFUL RECOMMANDATION
When leaving devices on working devices in the laboratory, users must tell the person in charge of the laboratory. In addition, they must place a note on the device in order to inform the personnal of the laboratory that an experiment is in progress.