Writing this week in the Proceedings of the National Academy of Sciences (PNAS), the Wisconsin group, led by UW-Madison physiologist Edwin R. Chapman, describes the development of two assays for botulinum toxin - one a real-time test - that vastly improve on current technologies to detect the deadly poison.

"We needed a real-time assay," says Chapman, suggesting the technology could potentially be deployed to protect the food supply, soldiers on the battlefield, or used by emergency responders dealing with an unknown agent. "The old test takes days."

In addition to the real-time assay, which could be deployed in a kit and used in the field, the Wisconsin team also developed a cell-based assay that helps provide a glimpse of the toxin doing its dirty work in living cells. This technology promises a rapid screen for millions of chemicals to see which might inhibit the paralyzing effects of the toxin, according to Min Dong, a UW-Madison post-doctoral fellow and the lead author of the PNAS report.

"The primary application is to conduct cell-based, large-scale screening for toxin inhibitors," Dong says. "A cell-based assay has the potential to reveal molecules that may inhibit various toxin action pathways."

Botulinum toxin is made by a bacterium that causes food poisoning. The poison is the most toxic substance known, six million times more potent than rattlesnake venom. It works by binding to nerve endings. The toxin is taken up by the nerves where it blocks chemical signals from reaching muscles. With enough blocked nerve endings, the toxin can cause paralysis and death.

In recent years, the nerve toxin has been used therapeuticall
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Contact: Edwin Chapman
chapman@physiology.wisc.edu
608-263-1762
University of Wisconsin-Madison
27-Sep-2004