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A molecule discovered in the gut of a microscopic worm could help
researchers protect crops from insect pests and develop new ways of treating
parasitic infections in people, according to research in the latest issue of
Science, February 2005 by Priya Shetty.

Researchers, led by Raffi Aroian of the University of California ? San
Diego, United States, say the molecule makes roundworms and insects
vulnerable to a natural toxin called Bt.

The Bt toxin 'recognises' the molecule's shape and attaches itself. This
leads to the insect or worm's gut rupturing and the animal dying.

Organic farmers use the Bt toxin, which comes from a bacterium called
Bacillus thuringiensis, to ward off crop pests. It is also used in crops
that have been genetically modified to resist attack by insects. However,
both approaches carry the risk of insects developing resistance to the
poison.

Aroian told SciDev.Net that his team's work could allow such resistance to
be monitored, as researchers would be able to look out for changes in the
structure of the molecule that the Bt toxin latches onto.

Any change to the structure could mean that the insect is no longer
susceptible to the toxin. Farmers could use this information to alter
practices in the local area to prevent the spread of resistance. Aroian
suggests that combining pesticides that target different molecules could
also slow the development of resistance.

The researchers also believe that the Bt toxin ? which is harmless to
humans ? could be used to treat parasitic roundworm infections in people.
The developing world is most heavily-affected by these parasites, which
include the worms that cause river blindness and elephantiasis.

Aroian says the low cost of making pills containing the Bt toxin would make
such a therapy accessible to people in developing countries.

Link to full research paper in Science:

[www.sciencemag.org];
keytype=ref&siteid=sci

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