[Taxacom] Palcohol?

[David Campbell]

I think that the actual culprit for trashing DNA is water.  The problem
with isopropanol is that it is not as effective for replacing the water as
ethanol is, allowing the DNA to degrade.  Similarly a low concentration of
ethanol won't preserve the DNA.  Depending on the size and composition of
the taxon, the water from the tissues may significantly dilute the
preservative.


On Tue, Apr 22, 2014 at 11:23 AM, Ken Kinman <kinman at hotmail.com> wrote:

> Hi all,
>       I've never stored insects in alcohol, but I've read that both
> ethanol and isopropanol can make them brittle (some say ethanol is worse,
> others say isopropanol is worse).  But there does seem to be agreement that
> concentrations above 70% of either of them can definitely make them
> brittle.  Anyway, I am wondering if the addition of glycerol helps mitigate
> that problem.  A few of my spider specimens were saved from dehydration
> when the alcohol evaporated over the years, but the glycerol kept them
> moist.                             -----------------Ken
> P.S.  I couldn't find anything about DNA being trashed by isopropanol.  It
> is often used to extract DNA, so does it only trash the DNA over a long
> time period?  Most of my spiders were collected in the 1970s.
>
>
> ------------------------------------------------------------------------------------------------------------
>
> > On 22.04.2014 13:15, John Noyes wrote:
> > > Apart from trashing DNA, it also trashes many types of smaller
> > > insects by making them so stiff that the become difficult/impossible
> > > to card-mount or put on slides. The same also goes for IMS.
> > >
> > > John
> > >
> > > John Noyes
> > > Scientific Associate
> > > Department of Life Sciences
> > > Natural History Museum
> > > Cromwell Road
> > > South Kensington
> > > London SW7 5BD
> > > UK
> > > jsn at nhm.ac.uk
> > > Tel.: +44 (0) 207 942 5594
> > > Fax.: +44 (0) 207 942 5229
> > >
> > > Universal Chalcidoidea Database (everything you wanted to know about
> > > chalcidoids and more):
> > > www.nhm.ac.uk/chalcidoids
> > >
> > >
> > > -----Original Message-----
> > > From: taxacom-bounces at mailman.nhm.ku.edu
> > > [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Daniel
> > > Janzen
> > > Sent: 22 April 2014 22:38
> > > To: Neal Evenhuis
> > > Cc: taxacom at mailman.nhm.ku.edu
> > > Subject: Re: [Taxacom] Palcohol?
> > >
> > > It is my understanding that isopropyl alcohol trashes DNA or
> > > otherwise makes it very difficult to extract.  Think on that for
> > > pickling museum specimens.  I know of no circumstance where you can
> > > get (or ship) isopropyl but not get (or ship) 80-95% ethanol.
> > >
> > > Just a thought.   Dan Janzen
> > >
>
>
> _______________________________________________
> Taxacom Mailing List
> Taxacom at mailman.nhm.ku.edu
> http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> The Taxacom Archive back to 1992 may be searched at:
> http://taxacom.markmail.org
>
> Celebrating 27 years of Taxacom in 2014.
>



-- 
Dr. David Campbell
Assistant Professor, Geology
Department of Natural Sciences
Box 7270
Gardner-Webb University
Boiling Springs NC 28017