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From: TSS ()
Subject: Organic polyanions act as complexants of prion protein in soil
Date: January 4, 2008 at 9:54 am PST

Organic polyanions act as complexants of prion protein in soil

Maurizio Polanoa, b, Claudio Anselmia, c, , , Liviana Leitad, Alessandro
Negroe and Maria De Nobilib
aSISSA, Via Beirut 2-4, I-34014 Trieste, Italy
bDepartment of Agriculture and Environmental Sciences, Università di Udine,
Via delle Scienze 208, I-33100, Italy
cCNR-INFM-DEMOCRITOS, Via Beirut 2-4, I-34014 Trieste, Italy
dC.R.A., Centro di Ricerca per lo Studio delle Relazioni Pianta-Suolo, Sede
Distaccata di Gorizia, Via Trieste 23, I-34170 Gorizia, Italy
eCRIBI Biotechnology Centre, Università di Padova, Via U. Bassi 58/b,
I-35131 Padova, Italy
Received 13 December 2007. Available online 2 January 2008.


The persistence of prions, the causative agents of transmissible spongiform
encephalopathies, in soil constitutes an environmental concern and
substantial challenge. Experiments and theoretical modeling indicate that a
particular class of natural polyanions diffused in soils and waters,
generally referred to as humic substances (HSs), can participate in the
adsorption of prions in soil in a non-specific way, mostly driven by
electrostatic interactions and hydrogen bond networks among humic acid
molecules and exposed polar protein residues. Adsorption of HSs on clay
surface strongly raises the adsorption capacity vs proteins suggesting new
experiments in order to verify if this raises or lowers the prion

Prions Adhere to Soil Minerals and Remain Infectious

Christopher J. Johnson1,2, Kristen E. Phillips3, Peter T. Schramm3, Debbie
McKenzie2, Judd M. Aiken1,2, Joel A. Pedersen3,4*

1 Program in Cellular and Molecular Biology, University of Wisconsin
Madison, Madison, Wisconsin, United States of America, 2 Department of
Animal Health and Biomedical Sciences, School of Veterinary Medicine,
University of Wisconsin Madison, Madison, Wisconsin, United States of
America, 3 Molecular and Environmental Toxicology Center, University of
Wisconsin Madison, Madison, Wisconsin, United States of America, 4
Department of Soil Science, University of Wisconsin Madison, Madison,
Wisconsin, United States of America

An unidentified environmental reservoir of infectivity contributes to the
natural transmission of prion diseases

(transmissible spongiform encephalopathies [TSEs]) in sheep, deer, and elk.
Prion infectivity may enter soil

environments via shedding from diseased animals and decomposition of
infected carcasses. Burial of TSE-infected

cattle, sheep, and deer as a means of disposal has resulted in unintentional
introduction of prions into subsurface

environments. We examined the potential for soil to serve as a TSE reservoir
by studying the interaction of the diseaseassociated

prion protein (PrPSc) with common soil minerals. In this study, we
demonstrated substantial PrPSc

adsorption to two clay minerals, quartz, and four whole soil samples. We
quantified the PrPSc-binding capacities of

each mineral. Furthermore, we observed that PrPSc desorbed from
montmorillonite clay was cleaved at an N-terminal

site and the interaction between PrPSc and Mte was strong, making desorption
of the protein difficult. Despite

cleavage and avid binding, PrPSc bound to Mte remained infectious. Results
from our study suggest that PrPSc released

into soil environments may be preserved in a bioavailable form, perpetuating
prion disease epizootics and exposing

other species to the infectious agent.

Citation: Johnson CJ, Phillips KE, Schramm PT, McKenzie D, Aiken JM, et al.
(2006) Prions adhere to soil minerals and remain infectious.

PLoS Pathog 2(4): e32. DOI: 10.1371/


Introduction. ...snip...end...tss

Thursday, January 3, 2008



On March 15, 2006, USDA–APHIS confirmed that a sample from an Alabama cow
tested positive for BSE. The cow was euthanized and buried on the farm ...

(please note, this was an atypical BSE i.e. h-BASE, same as the Texas mad
cow case, which seems to be more virulent than the BSE phenotype. ...tss)

full text link ;


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