Manganese Enhances Prion Protein Survival in Model Soils and Increases Prion Infectivity to Cells

Prion diseases are considered to be transmissible. The existence of sporadic forms of prion diseases such as scrapie implies an environmental source for the infectious agent. This would suggest that under certain conditions the prion protein, the accepted agent of transmission, can survive in the environment. We have developed a novel technique to extract the prion protein from soil matrices. Previous studies have suggested that environmental manganese is a possible risk factor for prion diseases. We have shown that exposure to manganese is a soil matrix causes a dramatic increase in prion protein survival (∼10 fold) over a two year period. We have also shown that manganese increases infectivity of mouse passaged scrapie to culture cells by 2 logs. These results clearly verify that manganese is a risk factor for both the survival of the infectious agent in the environment and its transmissibility

Enzyme adsorption on soil mineral surfaces and consequences for the catalytic activity

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Conformational changes of bovine serum albumin induced by adsorption on different clay surfaces: FTIR analysis

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Conformational Changes of Bovine Serum Albumin Induced by Adsorption on Different Clay Surfaces: FTIR Analysis

International audienceInteractions between proteins and clays perturb biological activity in ecosystems, particularly soil extracellular enzyme activity. The pH dependence of hydrophobic, hydrophilic, and electrostatic interactions on the adsorption of bovine serum albumin (BSA) is studied. BSA secondary structures and hydration are revealed from computation of the Amide I and II FTIR absorption profiles. The influence of ionization of Asp, Glu, and His side chains on the adsorp-tion processes is deduced from correlation between p 2 H dependent carboxylic/carboxylate ratio and Amide band profiles. We quantify p 2 H dependent internal and external structural unfolding for BSA adsorbed on montmorillonite, which is an electronegative phyllosil-icate. Adsorption on talc, a hydrophobic surface, is less denaturing. The results emphasize the importance of electrostatic interactions in both adsorption processes. In the first case, charged side chains directly influence BSA adsorption that generate the structural transition. In the second case, the forces that attract hydrophobic side chains toward the protein-clay interface are large enough to distort peripheral amphiphilic helical domains. The resulting local unfolding displaces enough internal ionized side chains to prevent them from establishing salt bridges as for BSA native structure in solution. On montmorillonite, a particular feature is a higher protonation of the Asp and Glu side chains of the adsorbed BSA than in solution, which decreases coulombic repulsion

Chymotrypsin adsorption on Montmorillonite: Enzymatic activity and kinetic FTIR structural analysis

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Structural changes of human serum albumin immobilized on chromatographic supports: a high-performance liquid chromatography and Fourier-transform infrared spectroscopy study

International audienceChiral stationary phases obtained by immobilization of HSA on [C8] and [C18] reversed-phases and on poly(1-vinylimidazole)-coated silica were tested to resolve dl-tryptophan, N-benzoyl-dl-phenylalanine, RS-oxazepam and RS-warfarin racemic mixtures. Parameters of enantioselectivity measured in HPLC are correlated to structural and solvation states for adsorbed HSA, evaluated by FTIR spectroscopy. HSA immobilized on [PVI]-anion-exchangers is highly selective. HSA molecules are not self-associated, only unfolded for a small hydrophobic helix. The HSA-coated reversed-phases have a lower selectivity. Unfolding is larger but the indole-benzodiazepine chiral site is preserved and remains accessible

Protein intercalated bentonite recovered using adsorption from stickwater

Wastewater from the meat rendering industry is called stickwater and contains about 4 wt% protein and has a high biological oxygen demand (approximately 150,000 mg/l). Large volumes require treatment prior to disposal, leading to a potentially useful source of protein being lost. In this study the organic fraction of stickwater (largely protein) was recovered by adsorption onto bentonite followed by centrifugation. Adsorption behavior was examined for a range of pH and clay concentrations. Equilibrium behaviour was described using the Langmuir–Freundlich isotherm. 25% organics can be recovered from stickwater without clay at pH below 5. Organic matter recovery was between 75 and 90% at 1 g clay per 20 g solution. Recovery decreased with increasing pH above pH 7–25% at pH 12, but was independent of pH at higher clay concentrations. Bentonite basal spacing increased from 13 to 23.5 Å for all pHs showing that protein had intercalated between clay layers. At high pH, bentonite had a positive charge on its edges, giving an expanded structure with a low pellet density at 17% solids, whereas at pH below 5 pellet density was between 25 and 33% solids. This has implications for downstream processing because more water would need to be removed, increasing downstream processing costs. Using between 5 and 10 g clay/200 g solution, adsorption was sufficient to give greater than 60% organics recovery. Processing would therefore be a trade off between using as as little as possible clay to minimise cost and maximise percentage organics adsorbed per gram of clay, while maximising recovery and maintaining small process volumes