Storage of Competent Cells

R. P. Grant +44 1 865 221018 rpgrant at
Fri Jun 30 12:01:17 EST 1995

In article <gddavis-3006950821270001 at>, gddavis at (Greg Davis) writes:
> I have a protocol for preparing and storing E. coli cells for
> electroporation.  The maxumum storage life is claimed as 6 months after
> freezing in a dry ice/ethanol bath and storing at -70oC.
> Is there a good method for long term storage of cells prepared by the
> CaCl2 method which retains high transformation efficiencies?

Our experience is that freezing in liquid nitrogen and then direct transfer to 
-80 works best.  Some lines can survive slight warming, but some are very 
difficult (especially if your -80 goes up to -40.. :(  


Richard P. Grant MA DPhil      rpgrant at
Nuffield Department of Obstetrics and Gynaecology, University of Oxford.
FAX +44 1 865 69141            TEL +44 1 865 221018

"Every four seconds somewhere in the world someone gives birth. 
Gentlemen, we have to find this woman and stop her." 

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