Place: 4274 Chamberlin (Refreshments will be served)
Speaker: Joel Pedersen, UW Department of Soil Science
Abstract: Prions are the enigmatic etiological agents of transmissible spongiform encephalopathies (TSEs), a class of fatal neurodegenerative diseases affecting humans and other mammals. The pathogenic prion protein is a misfolded form of the host-encoded prion protein and represents the predominant, if not sole, component of the infectious agent. Environmental routes of TSE transmission are implicated in epizootics of sheep scrapie and chronic wasting disease of deer, elk, and moose. Soil is the most plausible candidate for preserving prion infectivity in the environment. We have investigated prion attachment to and detachment from inorganic and organic soil particle surfaces and examined the effect of association with specific soil constituents on disease transmission. Interaction of prions with some phyllosilicate mineral surfaces is remarkably strong. Interestingly, rather than diminishing bioavailability, attachment to such particles enhances disease transmission. This finding suggests an explanation for environmental disease transmission despite the presumably low levels of prions shed by infected animals. Our results to date suggest that prions released into many soil environments are preserved near the surface in a bioavailable form, likely perpetuating prion disease epizootics and exposing other species to the infectious agent. The high stability of prions observed in other contexts may contribute to their survival in the natural and engineered environments.