X-Message-Number: 20700
From: "Ben Best" <>
Subject: Scientists bring 2,800 year old frozen bacteria to life
Date: 23 Dec 2002 15:54:42 -0800

  Bill Faloon asked me to post this to CryoNet -- Ben Best

Life Extension Weekly Update Exclusive
Scientists bring 2,800 year old frozen bacteria to life

In an article published in the Proceedings of the National
Academy of Sciences online, a team of scientists reported
reviving frozen microbes that are at least 2,800 years old found
in an ice-sealed lake in Antarctica. Coauthor John C Priscu,
of Montana State University stated, "These life forms may possess
novel ice-active substances such as antifreezes and ice nucleation
inhibitors that allow the organisms to survive the freeze-thaw
cycles and come back to life when exposed to liquid water. Importantly,
the cold temperatures preserve DNA extremely well making them
perfect 'ice museums' for the study of ancient DNA." 

The researchers took samples from the frozen lake and thawed
them to approximately 4 degrees Celsius. The bacteria were
administered radioactive-labeled carbon dioxide and thymidine,
which are involved in photosynthesis and DNA formation, respectively.
After incubation with the tracers, the amount of radioactivity
incorporated into the cell bodies was determined. This process
demonstrated the microbes' viability and allowed their potential
growth rates to be assessed. 

Dr Priscu told Life Extension Weekly Update, "Results from our
experiments told us that the microbes can resume active
metabolism once they 'see' liquid water. There is always the
possibility that the cells may have been metabolizing slowly
in the 'solid ice', something we did not test for. It is know
that for purely physical reasons, liquid water exists between
the boundaries of ice crystals and between the ice-sediment boundaries.
My laboratory is actively examining the possibility of metabolism
occurring at these interfaces in 'solid ice', but we have yet
to show it unequivocally. Given what we have learned over the
past 10
years about life in icy environments, I strongly believe that
microbes do metabolize in solid ice-we just have to prove it!
It will be a major scientific breakthrough if and when we do
show that life does actively grow in solid ice. "

He added, "Several of the microbes we have isolated so far
appear to produce some type of ice active substance (IAS) that
inhibits ice nucleation in their membranes. Some of these IAS's
resemble dimethyl sulfoxide (DMSO), which was used routinely
by athletes as a liniment for joint pain. These IAS's allow the
cells to live through repeated freeze-thaw cycles without membrane
damage. Try freezing and thawing your finger several times in
your freezer and you will see that humans do not have this capability
(tissue in your finger will die and the finger will self amputate).
So, these secondary metabolic products allow the microbes to
survive extreme cold and may someday provide humans with a natural
product to help maintain cell integrity under
extremely cold conditions."

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