Natural Antifreeze. Humans
have fantasized for years about the time when they would be able to deep-freeze
someone and restore him to life sometime in the future. For some frogs,
however, this is no fantasy. They do it every year.
Like other animals, frogs are faced with the
problem of surviving winter without central heating or hearth fires. Their
solution? They “just squat in the open until they freeze solid,” says a report
in The Toronto Star. When spring comes around, the frog thaws
out and starts croaking again.
Why doesn’t the freezing kill him? Biologist
Kenneth Storey says: “We found frogs produce an anti-freeze molecule that we
didn’t expect at all: glucose. People had said there was no way to use that as
an anti-freeze, but frogs can.” Seemingly, because of this glucose, when the
frog freezes, its tissue fluids turn to syrup instead of forming ice crystals
that would expand and rupture its cells.
Anti-Antifreeze.
The
magazine Science Digest reports that certain creatures in Antarctica
have a natural antifreeze that helps them keep moving in cold weather. However,
when the temperature gets too low, they freeze and die. A tiny wingless
fly—whose name, Belgica antarctica, is much bigger than he
is—also uses the natural antifreeze to keep moving in ordinary cold weather.
But when very cold weather threatens, he uses an “anti-antifreeze” chemical to
survive. Long before the temperature gets dangerously low, the
“anti-antifreeze” stops the action of the antifreeze. Why?
“By
inducing the insect to freeze at fairly warm temperatures, the special
anti-antifreeze compound insures that ice forms at a slow rate. At lower
temperatures, rapid freezing would remove water from its cells too quickly, and
the animal would die as a result.” But since Belgica antarctica
freezes gently, he survives and simply thaws out when the temperature rises
again.
And the Smart
Potato. A perennial problem for farmers is controlling
infestation by aphids such as the greenfly. According to a report in the Daily
Mail, it seems that one type of potato has solved the problem all by
itself.
Scientists in Hertfordshire, England,
discovered that the potato plant Solanum berthaultii produces a
chemical that is exactly the same as that given off by a dying aphid to warn
other aphids. The plant is left in peace as aphids, alarmed by the chemical,
give it a wide berth.
