Oligo stability in water at -20 C

Michael T. MacDonell sendero at ix.netcom.com
Tue Aug 11 10:53:53 EST 1998

Dear Keith:

Bacteria are little bags of nucleases. The bacteria do not have to be
active only the nucleases.

The fundamental problem, I suppose, is that people seem to keep seeing
what seems to them to be autolysis of oligos under questionable
conditions.  The studies that have been published seem to indicate
that DNA does not self-destruct, unless in the presence of ionizing
radiation or other source of free radicals.  Back with LTI was BRL
they published a study on the effects of enormous numbers of
freeze-thawing cycles on DNA, and could not show any damage whatever.
It was published in one of their early newsletters, and it has been
cited often. I am sure they can provide you with a copy.

The problem I have with these reports of spontaneous degradation of
oligos, is that I have worked with oligos for years and years, and I
do not see it.  We have customers who report the same thing. 

There is another fellow at New Mexico, who claims to have data from a
controlled study which seems to indicate that DNA does degrade on its
own.  He should publish this in a peer reviewed journal, since it is
important information.

Maybe I have been lucky, but I do not see it.
On the other hand, I worked with RNA for years and I never saw the
alarming tendency to self-destruct that others saw.  The tough thing
is to separate myth from science.  Publication helps.

Best Regards,

On Tue, 11 Aug 1998 06:56:11 GMT, Keith.Rand at molsci.csiro.au (Keith
Rand) wrote:

>In article <35cf16cb.216714738 at nntp.ix.netcom.com>, sendero at ix.netcom.com
>(Michael T. MacDonell) wrote:
>> 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,
>> Mike
>You have me worried. I havn't heard of bacteria degrading oligos at -20 or
>-80. Is this a generally known and accepted thing?
>Keith Rand,  Sydney Australia

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