Freeze-thawing permanent stocks

Richard heath at
Mon Nov 7 13:37:58 EST 1994

In article <39ciaq$ogi at>, bchs1b at Jane.UH.EDU (Michael Benedik) writes:
> Does anyone know the survival of frozen perms stored in glycerol at -80
> after thawing and refreezing? I have a bunch of frozen perms which
> I would like to transfer into new vials. It would be easiest to thaw
> them and decant into the new vials. There are hundreds of stocks and
> I would rather not have to regrow them all. These are mostly E. coli
> strains.
> **********************************************************************
> Michael Benedik						benedik at
> Department of Biochemical Sciences
> University of Houston
There was a thread a while back on the best way to store stocks of E. coli. 
Cells stored in glycerol will lose viability while just sitting in your freezer
over several years.  We store our stocks in 7% DMSO without antibiotics.  These
remain viable for *ages*, and survive repeated freeze/thawing.  Glycerol stocks
will be OK after several rounds at least, but it may be worth the effort of
regrowing and transferring to DMSO.....(I wouldmn't want to be the one to do it

Good luck!

Richard Heath

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