A Peculiar Event In Tranformation
dunman at njmsa.UMDNJ.EDU
Wed Jun 18 16:41:04 EST 1997
Randy Willis <willis at gandalf.psf.sickkids.on.ca> writes:
>Paul N Hengen wrote:
>> But, will they be able to grow under non-selective conditions? I think the
>> cells undergo more stress (not less) at 4C. I used to keep all my slants of
>> E. coli at 4C until I found out they last much longer if stored at room temp.
>> Then again, who needs the cells when you're studying plasmids? I now just
>> make sure to keep any plasmid DNA I'm interested in at -20C.
>You may be correct. My use of the word "stress" is very hand-waving. I
>do agree that it is best to keep a solution of DNA at -20C, and I do. I
>wonder what peoples' experiences have been with using cells taken from
>stocks which have been frozen at -70C. We maintain stocks, but
>typically this is in case we run out of plasmid DNA and NOT for the
>purposes of growths/expressions. Any suggestions or ideas?
>Best of luck to all in their endeavours...Randy
Our lab typically stores all strains at -20C & -70C in 40% gylcerol.
I've had trouble recessitating (sp) strains from -20C after they've been
stored for several years. However, I've never had trouble recessitating
strains from -70C. I directly plate on selective media & "knock on wood"
haven't ran into a problem yet. I should also mention, all plasmids are
also purified & stored @ -20C...just in case.
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