October 20, 2005

Canadian researchers find anti-freeze in fleas

By Julie Mollins

TORONTO (Reuters) - Tiny fleas that survive on fungus found
under a blanket of snow contain a unique antifreeze that could
have implications for farming or transplant surgery, Canadian
researchers said on Wednesday.

The researchers, whose report is published in the latest
edition of Science, said their findings could help protect
plants or animals from frost, or allow donated transplant
organs to be stored and transported at lower temperatures.

The six-legged snow fleas are between 1 and 2 millimeters
long (0.04 to 0.08 inches), with six legs and no wings.

They are also known as springtails because they have an
abdominal spring called a furcula that lets them jump away from

Their bodies contain proteins that limit the growth of ice
by lowering the freezing point of fluids by 6 degrees Celsius
(11 degrees Fahrenheit), said the researchers, from Queen's
University in Kingston, Ontario.

One practical application of the study could be to store
transplant organs at cooler temperatures to preserve them for

"If you can profuse, or basically run a solution with an
antifreeze protein and flood an organ with it, you might then
be able to store it at lower temperatures and the antifreeze
would prevent the organ from actually freezing," said Laurie
Graham, one of the two researchers who carried out the study.

"Theoretically, with this antifreeze protein we might be
able to store an organ at minus 6 degrees (21 degrees
Fahrenheit). Hopefully, it would be able to last longer so that
you would have longer to do tissue matching to get the organ to
the patient and just increase the shelf life of organs."

She said frozen foods could also benefit from the
discovery, if the antifreeze, which she derived from crushed
snow fleas, can be used to inhibit freezer burn.

Another possible application could be in crops, allowing
fruit trees to survive a cold snap.

"If you were able to genetically modify any crop that was
susceptible to frost you may be able to generate a crop that's
not so sensitive," Graham said.

The researchers found that the antifreeze proteins in the
snow fleas were different from those in beetles and moths,
prompting Graham and her research partner, Queen's University
biochemistry Professor Peter Davies, to conclude that these
antifreeze proteins evolved independently in the snow fleas.

"There would have been climate change and the organisms
were challenged by a new environment," Graham said. It's almost
like nature has had to reinvent the wheel."

The snow flea is wingless and is not related to the biting
flea, which is a true insect.