[NHCOLL-L:4115] RE: Possible replacement to alcohol storage?

Tue Dec 9 15:36:58 EST 2008

Very true, DNA is sensitive, especially mine:-)

We have the luxury of having a Laboratory of Molecular Biology and their
optimum for long-term DNA storage is in liquid Nitrogen containers, but
that is beyond the resources of many institutions - we got them before
the economy went bad:-)

However, the attached publication (Vink et al., 2005) does show that
Propylene Glycol is an excellent preservative for DNA, especially for
arthropods.  I believe that now there are other publications confirming
this.

******************************************************

David G. Furth, Ph.D.

Department of Entomology

MRC 165, P.O. Box 37012

National Museum of Natural History

Smithsonian Institution

Washington, D. C. 20013-7012  USA

Phone: 202-633-0990

Fax: 202-786-2894

Email: furthd at si.edu <mailto:furthd at si.edu> 

Website: www.entomology.si.edu <http://www.entomology.si.edu>  

________________________________

From: John E Simmons [mailto:simmons.johne at gmail.com] 
Sent: Monday, December 08, 2008 11:53 PM
To: Furth, David
Cc: JBRYANT at riversideca.gov; Makos, Kathryn; NHCOLL-L at lists.yale.edu
Subject: Re: [NHCOLL-L:4099] RE: Possible replacement to alcohol
storage?

Opinions vary widely about the suitability of various fluids for
preserving tissues for DNA, which is not surprising given the number of
variables that can affect DNA quality (e.g., length of time between cell
death and sampling, cleanliness of the operation, whether the tissue
sample was exposed to UV in the field, storage temperature, type of
plastic used for the sample tubes, the technique used to extract DNA).  

I believe that we can say that the best method for long-term storage of
tissues for DNA is freezing at -80C, and of the various solutions
proposed for holding tissues without freezing, 95% ETOH is best.  

Although there have been a lot of publications about one buffer or
mixture or another, we don't yet have comparative long-term data to say
much more than that.  Many people who favor a particular buffer or fluid
have based their opinion on incomplete data--they usually don't know
much about how the samples were collected and stored, so it is difficult
to make comparisons.

Personally, I would avoid (if at all possible) glycols and phenoxytols
which are really little more than detergents, and use a good
preservative--or DNA this means a quick dehydration method (freezing or
alcohol), keep the sampling equipment as clean as possible, and protect
the tissues from heat and ultraviolet radiation. 

--John

On Mon, Dec 8, 2008 at 6:16 PM, Furth, David <FURTHD at si.edu> wrote:

All good points.  

Relative to point number 2, there have been some publications about the
use and effectiveness of propylene glycol to preserve DNA.  Also our
Invertebrate Zoology has been using Propylene Phenoxytol or a similar
"sorting solution", especially for smaller-bodied specimens with
exoskeletons (e.g., plankton) otherwise stored in formalin.  However, I
am not certain about the length of time this has been used successfully.

******************************************************

David G. Furth, Ph.D.

Department of Entomology

MRC 165, P.O. Box 37012

National Museum of Natural History

Smithsonian Institution

Washington, D. C. 20013-7012  USA

Phone: 202-633-0990

Fax: 202-786-2894

Email: furthd at si.edu <mailto:furthd at si.edu> 

Website: www.entomology.si.edu <http://www.entomology.si.edu>  

________________________________

From: owner-nhcoll-l at lists.yale.edu [mailto:
owner-nhcoll-l at lists.yale.edu] On Behalf Of John E Simmons
Sent: Saturday, November 29, 2008 9:30 PM
To: JBRYANT at riversideca.gov
Cc: Makos, Kathryn; NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4099] RE: Possible replacement to alcohol storage?

This is a very interesting discussion, and I am pleased to see the level
of interest in the topic. I would like to add a few points:

1.  Museums lack proper studies of what happens to containers of 70%
ethanol or "10% formalin" during a fire.  Data exists for storage of
retail liquor (which averages less than 15% alcohol) and bulk storage of
95% alcohol in large drums, but museum collections and specimens on
exhibit fall in between.  The cost of such studies is very high--it
would be great if Factory Mutual or some outfit like that would take up
the cause.  We know that ethanol is flammable, but we also know that
ethanol fumes disperse very quickly from an opened container or a spill,
greatly reducing the fire hazard.  We really don't know how much of a
danger the specimens pose, but we do know it is far less than 95%
alcohol (the rules for 95% alcohol are frequently applied to museum
collections).  In their defense, we must remember that the regulatory
agencies have to make a guess by extrapolating from existing
regulations, which usually leaves all parties unhappy.

2.  We need to keep in mind the difference between a preservative (a
chemical that prevents deterioration from occurring, such as alcohol or
formaldehyde) and a "holding solution" that might be used in the short
term while a fluid preserved specimen is on exhibit or used in a
classroom (e.g., Novec, or the available proprietary fluids such as
Wardsafe or Carosafe that contain glycols, phenols, and other
compounds).  The "holding solutions" don't preserve specimens long-term
and may be very harmful to the specimen.

3.  The literature on fluid preservation is full of recommendations of
oddball concoctions that various individuals have claimed are good
preservatives, but most of them are not.  To avoid adding even more
anecdotal recipes to the mix, museums should follow the lead of the
Smithsonian and collect all the data they can from experiments with new
fluids.

--John

John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com
303-681-5708
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu

-- 
John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com
303-681-5708
www.museologica.com
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu

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