Re: Microbe Fossils-Mars
Enigl@aol.com
Mon, 25 Aug 1997 17:31:51 -0400 (EDT)
In a message dated 97-08-24 17:43:48 EDT, you write:
<< Which (if any) of the creatures you know of can survive long term in a
very high vacuum (say, under 10^-9 torr) at 3 degrees kelvin? Presumably,
most all water would be gone. >>
That just preserves the spores BETTER. Low water activity in the case of
spore survival is an advantage. For instance vacuum freeze drying is the
best method currently available for keeping spores alive. (Just add water and
nutrients to revive them). Suboptimal water activity will stop or slow
growth and can make some on-spore forms of bacteria _more_ susceptible to
other hostile conditions. You can look in the book _Preservative-Free and
Self-Preserving Cosmetics and Drugs_ (see below) the for which ones are
affected.
<< Of course, things might hide inside a rock
for much longer, with the pressure being much higher. >>
Vacuum is not considered to be a problem for for bacteria. For instance,
vacuum packed meat is vulnerable to _Clostridium botulinum_ (another spore
former, BTW) growth and botulism toxin formation.
Pressure is also not a problem for bacteria. I personally found no bacterial
reduction at 65,000 psig (the highest my system would go). Later, I read
120,000 psig also had no reduction in viability.
<<Do you know of any books or papers specifically discussing the survival of
organisms over extremely long time-spans?
>>
There are some really good books on microbiology in extreme environments.
Start by searching key words "extreme environments," "extremeophiles," and
looking at http://asmusa.org
You will need a university library, but look at _Applied and Environmental
Microbiology_ a journal, and the general text: _Microbiology_ by Prescott,
Harley and Klein.
------------------------------------------------------------------------------
--------------------------
Davin C. Enigl, MEAS, Master of Environmental Arts and Sciences
President-Microbiologist, HACCP Validations (tm). Quality Assurance, Quality
Control, Research and Development
Co-author of _Preservative-Free and Self-Preserving Cosmetics and Drugs_,
Kabara and Orth, eds. Copyright 1997,
Marcel-Dekker, ISBN 0-8247-9366-8, Telephone: 1-800-228-1160
Microbiology Services for: Biotechnology, Cosmetics, Foods, and
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August 25, 1997
2:09 pm PACIFIC