Ascertaining anthrax

A new laboratory method for quickly detecting active anthrax proteins within an infected blood sample at extremely low levels has been developed by researchers at the National Institute of Standards and Technology (NIST), the US Army Medical Research Institute of Infectious Diseases and the National Cancer Institute.

Current detection methods rely on injecting live animals or cell cultures with samples for analysis and require up to several days before results are available.

Described in an upcoming issue of the Journal of Biological Chemistry, the new method produces unambiguous results in about an hour. The researchers hope the system will ultimately be useful in developing fast, reliable ways to diagnose anthrax infections or to quickly screen large numbers of drugs as possible therapies for blocking the bacteria's toxic effects.

The method works by detecting changes in current flow when anthrax proteins are present in a solution. An anthrax protein called "protective antigen" spontaneously forms nanometer-scale pores that penetrate the surface of an organic membrane. When a voltage is applied across the membrane, positively and negatively charged ions flow freely in both directions through the pore.