X-Message-Number: 5717
Date: Fri, 9 Feb 1996 11:05:47 MST
From: "Richard Schroeppel" <>
Subject: Freezing small anoxic animals 

This is from a friend.  It mentions another way to reduce freezing damage.
I've never heard of this, so I thought I'd ask the experimenters here if
it's true?

[original correspondent's names deleted -- rcs]
    =>    Re water freezing in a cell: Actually it is the oxygen in the
    =>    surrounding fluid that destroys the cell.  The water crystals tear
    =>    the cell membrane, the oxygen rushes in, and presto! you get a
    =>    bleached cell.  However, and I am not making this up, if you
    =>    suffocate a small animal in pure nitrogen until it passes out,
    =>    then flash-freeze it, it will frequently recover and survive the
    =>    thawing.  I will leave the details to the imagination because it
    =>    will provoke interesting reparte.  (I won a science fair with this
    =>    trick once.)
    =>
    =>What do you mean by flash freeze?  When a cell freezes, isn't the
    =>nuclear membrane and the endoplasmic reticulum also trashed?

    If you suffocate the organism you have to freeze it extremely fast before 
    the tissues die from lack of oxygen.  The membranes are all disrupted, but 

    apparently they can seal again almost instantly in the absence of corrosive
    
    oxygen.  The trick is that the animals have to be very small so you can thaw
        them as quickly as you froze them.  It works with insects and with 
    vertebrates up to the size of small turtles.

    I used meal worms (Tenebrio molitor... gad what a memory).  Frozen and 
    thawed under normal air they died.  Frozen and thawed after passing out in 

    nitrogen, about 2/3's of them reanimated.  They didn't look happy, but they
        moved.

Rich Schroeppel   


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