Can I store my competent E. coli in liquid nitrogen?
We do not recommend storing competent E. coli strains in liquid nitrogen as the extreme temperature can be harmful to the cells. Also, the plastic storage vials are not intended to withstand the extreme temperature and may crack or break.
How should I store my competent E. coli?
We recommend storing our competent E. coli strains at -80°C. Storage at warmer temperatures, even for a brief period of time, will significantly decrease transformation efficiency.
I'm getting overgrowth of colonies. Why?
Ensure that you are using the correct antibiotic at the appropriate concentration. Additionally, make sure the antibiotic is not expired. If colonies exhibit unexpected morphologies, contamination could be a factor. Check your S.O.C. medium and LB growth medium.
I'm getting no colonies at all on my plates. Can you help?
We recommend trying the following:
- Carry out the puc19 transformation control; this gives you information about the performance of the cells.
- Check plates for expiration and correct media used (LB/agar).
- Confirm that the correct antibiotic and concentration was used.
What is the storage media for the competent cells?
Preparation procedures and formulations for all of our competent cells are proprietary. All chemically competent cells are delivered in an aqueous solution that contains a mixture of salts, along with a freezing stabilizer such as glycerol or DMSO.