Glycerol stocks at -20?

[Colin Rasmussen]

vwarwar at unlinfo.unl.edu (vitor warwar) wrote:
>
>     Hi all:
>
>     Does anybody knows of bacteria glycerol stocks could be
>     stored at -20 instead of -70?
>


Yes they can. We often do this for short-term (months) storage of things 
where we are sorting out which ones we will finally keep. For long-term 
storage (years) -70°C is better. We have found that viability at -20°C 
doesn't seem as good and I would hate to come back to something after a 
few years to find the bugs had died. If this does happen, you can often 
recover the plasmid by taking the seemingly dead glycerol stock, do a 
mini-prep to isolate plasmid and retransform into competent bacteria. We 
have recovered more than one clone in this way.

Colin