glycerol stocks - storage (Mar/12/2009 )
I recently discovered that a preious tech in our lab stored our glycerol stocks at -20 rather than -80. I know they have been there for at least 2 years and probably longer. I have attempted to streak several plates from several different stokes and got NOTHING. The stocks appear to look "icy". Is all lost?
Probably lost, unless the vials were flash frozen first. When freezing under higher freezing temperatures, ice crystals expand as the water freezes killing cells. In the presence of glycerol and rapid freezing, this effect is minimized.
If these are plasmid containing parts, then you can probably do a miniprep on the frozen samples to isolate plasmid, then retransform.