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This nasty mess is the result of sheep blowflies. Once
they could be killed by organophosphate insecticide, but in the
60's they developed a resistance to it.
Scientists from Australia's science
agency CSIRO were curious as to how it had happened. They discovered
that an enzyme in the resistant flies was changing just one amino
acid in the insecticide making it useless.
When the blow fly larvae was sprayed
instead of keeling over and dying, they ate the insecticide and
spat out non-toxic products. And we thought well if this enzyme
can do such a good job inside the fly, why can't it do a good job
outside of the fly.
Dr. Robyn Russell and her colleagues
thought they'd see if this enzyme would do its trick in cleaning
up insecticide contaminated soil. And along the way they discovered
a bacteria that did an even better job.
Bacteria, when they're faced with,
if they're sitting in the soil, in a cotton field for instance and
they come in contact with a lot of insecticide, they'll use the
insecticide as a food source. So rather than, like an insect does
chew up a little bit that might kill them, these bacteria will eat
it for breakfast.
After growing large amounts of the
right enzymes, in collaboration with the company Orica, tests were
conducted on run off water from cotton fields, where large amounts
of insecticides are used.
In the first instance what we're going
to be trying to do is to clean up residues in run off water. The
irrigation has occurred after the pesticides have been applied so
the water that then runs off is contaminated there with pesticides.
And that's what we'll be trying to clean up in the first instance.
It's hoped that eventually the enzyme
can be developed as a powder. Dr. Russell hopes it may even be possible
to insert genes, which produce the enzyme, into trees and bushes.
They could then clean up contaminated sites as they grow.
That's something I dream about. Why
not?
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