Quotes from the October 23,1999 edition of New Scientist:
'Master of survival, can withstand pressures six times greater than those at
the bottom of the ocean and endure temperatures ranging from more than 100 C
down to absolute zero. Can shrug off lethal radiation, survive in a vacuum and
go without water for more than a century.
It sounds like the resume of a superhero. But these traits belong to
little-known animals less than a milliter long that probably live on your
rooftop. Like superheroes, the animals conceal their cylindrical bodies, stumpy
legs and tiny claws have earned them the nicknames of "water bears" and "moss
piglets".
.......
Substituting trehalose for the water in membranes allows tardigrades to
survive for long periods without any water at all. The record is 120 years, held
by tardigrades taken from dried-out moss kept in a museum in Italy. Once their
membranes are safely coseted by trehalose, the animals can shut down their
metabolism and survive without oxygen or food.
Surviving extreme cold requires yet another clever trick. When they freeze,
the animals have to protect themselves against damage caused as ice crystals
grow. Westh has identified large proteins in an Arctic tardigrade that raise the
freezing point of the animal to ensure that it freezes quickly. This
creates lots of tiny crystals that are less likely than large ones to
damage cells, enabling some species to survive freezing in liquid helium.
.........
What can we learn from these survival experts? Harnessing the tardigrades
powers of self-preservation, Seki and his team have used trehalose to store rat
hearts for 10 days before reviving them (New Scientist, 7 November 1998 p 7).
The goal is to develop long-term organ banks for transplant operations. "We
believe that this method can be effectively applied to prolong the storage
periods of other organs as well," he says.
If brains can follow the hearts, then the preservation and resuscitation of
whole bodies might not be far behind. At present, only single mammalian cells
such as blood and sperm can be reliably stored for long periods, but tardigrades
have around 40,000 cells, including nerves. Such suspended animation has long
been the staple fare of science fiction, allowing humans to endure the tedium of
crossing vast interstellar distances. So while tardigrades might not have come
from the planet Tardigron, they might one day lead us there."