Oligo stability in water at -20 C

Michael T. MacDonell sendero at ix.netcom.com
Mon Aug 10 10:53:01 EST 1998

Dear Chris:

The answer to most of your questions is "No".  Water, buffer, doesn't
matter. As far as the oligo is concerned, room temp, -20, -80, doesn't
matter.  Oligos are stable (although modifiers may not be). What you
are describing is nuclease degradation. Almost certainly caused by
bacterial contamination.  Talk to a Microbiologist, they can hep you.

Best Regards,

On 10 Aug 1998 14:33:12 GMT, chrisb at hgu.mrc.ac.uk (Chris Boyd) wrote:

>Some years ago, there was a discussion on this ng about oligos going
>off in storage. Paul Hengen wrote it up for TIBS
>(http://www-lecb.ncifcrf.gov/~pnh/papers/TIBS/jan95.html). The upshot
>was that, yes, some oligos do go off and some can be resuscitated by a
>brief 95 C heat pulse.
>We are currently suffering from an oligo problem such that some (too
>many in fact) oligos stored at -20 C for six months or more are found
>not to work for PCR (sometimes even when UNUSED). On HPLC analysis we
>can clearly see degradation of the enfeebled oligos. Legend has it that
>this didn't used to happen with a previous supplier's oligos. Most
>people here follow the current supplier's recommendation and dissolve
>the oligo (supplied as a dried down pellet) in water before freezing. 
>Others use TE. Could it be that water-dissolved oligos will go off
>faster than buffer-dissolved oligos (even at -20 C with no thawing) due
>to (eg) autohydrolysis? Has anyone any data on this, or any other
>thoughts about oligo stability? I see no reason why oligos that are OK
>to start with, and stored in suitable sterile enzyme-free media,
>shouldn't last for years.
>Best wishes,
>Chris Boyd                      | from, but not \ MRC Human Genetics Unit,
>Christopher.Boyd at hgu.mrc.ac.uk  | on behalf of  /  Western General Hospital,
>http://www.hgu.mrc.ac.uk/Users/Christopher.Boyd \   Edinburgh, EH4 2XU, SCOTLAND

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