title: Biochemical evidence for the proteolytic degradation of infectious prion protein PrPsc in hamster brain homogenates by foodborne bacteria.
abstract: PrP(Sc) is a general term to describe the infectious agent causing transmissible spongiform encephalopathy (TSE), and the protease-resistant form of cellular PrP(C). In this study, we have identified several protease-secreting bacteria able to degrade PrP(Sc) under more or less native conditions (30 degrees C, pH 8), focusing on strains isolated mainly from cheese. One hundred and ninty-nine protease-secreting isolates belonging to the Actinomycetales and Bacillales were screened for the expression of PrP(Sc) degrading activity by a Western blot procedure. Only 6 strains belonging to the following species were found to exhibit such an activity: Arthrobacter nicotianae, Bacillus licheniformis, Brachybacterium conglomeratum, Brachybacterium tyrofermentans and Staphylococcus sciuri and Serratia spp. As revealed by a general protease assay based on dye-labeled Azocoll substrate, the PrP(Sc) degrading activity was not directly correlated to the total level of secreted proteolytic activity of these organisms. This indicates that specific proteases are required for the degradation of PrP(Sc). Our study also suggests the potential use of such starter bacteria or their proteases for application in PrP(Sc) degradation and decontamination under native conditions.
authors.affiliation: Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung, Technische Universität München, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Müller-Hellwig
authors.forename: Martin H
authors.initials: MH
authors.lastname: Groschup
authors.forename: Rohtraud
authors.initials: R
authors.lastname: Pichner
authors.forename: Manfred
authors.initials: M
authors.lastname: Gareis
authors.forename: Erwin
authors.initials: E
authors.lastname: Märtlbauer
authors.forename: Siegfried
authors.initials: S
authors.lastname: Scherer
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Loessner
mesh_terms: D000192:Actinomycetales / Q000378:metabolism; D000818:Animals; D001173:Arthrobacter / Q000378:metabolism; D001407:Bacillus / Q000378:metabolism; D001673:Biodegradation, Environmental; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002611:Cheese / Q000382:microbiology; D006224:Cricetinae; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D018620:PrPSc Proteins / Q000032:analysis / Q000378:metabolism*; D012705:Serratia / Q000378:metabolism*; D013210:Staphylococcus / Q000378:metabolism
chemical_list: D018620:PrPSc Proteins; D010447:Peptide Hydrolases