A Human-Safe Alternative to Organophosphate Insecticides

Researchers at the University of Minnesota and Mayo Clinic have been collaborating for more than five years as a part of a special project on biotechnology and medical genomics. But now they have turned their attention from patients to pests. The scientists have successfully developed a human-safe pesticide that specifically targets aphids, a bug that has been ravaging crops worldwide.

Aphids are normally controlled by organophosphate insecticides that block the activity of acetylcholinesterase (AChE), an enzyme vital for regulating the neurotransmitter acetylcholine. Organophosphates target a catalytic serine residue in AchE. Because these agents also affect vertebrate AChE, they are toxic to non-target species including humans and birds. Several studies have shown that organophosphate insecticides can enter the brain of young children and damage developing nervous system.

The team developed a small molecule that blocks nearly all AChE activity in greenbug and soybean aphid without inhibiting AChE in humans. Instead of targeting serine, the molecule the scientists developed blocks a cysteine residue in the AChE active site to which aphids and other insects cannot develop a resistance.

The open-access paper published by PLoS ONE is available at http://dx.doi.org/10.1371/journal.pone.0004349 Visit  http://newsblog.mayoclinic.org/2009/01/27/patients-to-pests/ for more information, including video and audio clips on the importance of the research.