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United States Department of Agriculture

Agricultural Research Service

Research Project: DETECTION OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY AGENTS IN LIVESTOCK, WILDLIFE, AGRICULTURAL PRODUCTS, AND THE ENVIRONMENT Title: Molecular approaches to detecting and discriminating among prions, a class of pathogenic molecules(Abstract)

Authors
item Silva, Christopher
item Onisko, Bruce
item Dynin, Irina
item Erickson-Beltran, Melissa
item Hui, Colleen
item Carter, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2012
Publication Date: June 15, 2012
Citation: Silva, C.J., Onisko, B.C., Dynin, I.A., Erickson-Beltran, M.L., Hui, C., Carter, J.M. 2012. Molecular approaches to detecting and discriminating among prions, a class of pathogenic molecules(Abstract). Meeting Abstract. Poster, 615.

Technical Abstract: Prions (PrPSc)are the pathogens that cause a set of fatal neurological diseases that include scrapie and chronic wasting disease (CWD). They are composed solely of protein and unlike viral, bacterial, or fungal pathogens, the information necessary to convert the normal cellular prion protein (PrPC) into a prion and thereby propagate the infection is contained solely in the conformation of the prion isoform. For a given host there are a number of possible prion phenotypes that can result from polymorphisms in PrPC or from different conformations of PrPSc. Detecting prions and discriminating among prion strains is challenging. We have developed two approaches. In the first we use a nano LC-MS-MS system to quantitate the prions present in a sample relative to isotopically labeled internal standards. Our limit of detection is in the attomole range(10-18 mole). Unlike other MS methods, this approach permits the quantitation of viable pathogens. This approach can be used to detect a variety of prion strains. A second approach uses small molecules to covalently modify PrP molecules. The chemical environment of the amino acids present in PrP is conformation (PrPSc or PrPC) dependent. This means that the same amino acid can react differently with the same chemical reagent, depending upon the conformation of that protein. By selecting reagents that covalently modify amino acid side chains in the epitope recognized by commercially available antibodies, we can use a combination of synthetic reagent/antibody/Western blot to detect the presence of prions and to distinguish among prion strains.

Last Modified: 10/1/2014
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