title: Comparison of detergent and protease enzyme combinations for the detection of scrapie-associated fibrils from the central nervous system of sheep naturally affected with scrapie.
abstract: Standardized samples of tissue from the central nervous system of four sheep naturally affected with scrapie and from four healthy control sheep were subjected to a centrifugal extraction technique used to obtain scrapie-associated fibrils; the latter were then demonstrated by negative-contrast transmission electron microscopy. This regime was used to evaluate the fibril yield obtained from the 25 possible combinations of five different detergents and five different proteolytic enzymes. N-lauroylsarcosine detergent was found to be the most efficient detergent for all five enzymes, followed by sulphabetaine 3-14. Sodium dodecyl sulphate detergent was successful only in combination with a subtilisin Carlsberg enzyme. Octylglucoside and nonidet P40 detergents did not produce fibrils with any of the enzymes. Proteinase K was the least efficient of the five enzymes when used in combination with N-lauroylsarcosine; subtilisin Carlsberg, clostripain, pronase and trypsin enzymes all gave higher fibril yields. A combination of N-lauroylsarcosine detergent and subtilisin Carlsberg proteolytic enzyme gave the highest fibril yield.
authors.affiliation: Veterinary Laboratories Agency, Central Veterinary Laboratory, Weybridge, Surrey, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Stack
authors.forename: A M
authors.initials: AM
authors.lastname: Aldrich
authors.forename: L A
authors.initials: LA
authors.lastname: Davis
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000473:pathology*; D003902:Detergents; D004338:Drug Combinations; D010450:Endopeptidases; D005260:Female; D008854:Microscopy, Electron; D009454:Neurofibrils / Q000648:ultrastructure*; D012608:Scrapie / Q000473:pathology*; D012756:Sheep; D012757:Sheep Diseases / Q000473:pathology*
chemical_list: D003902:Detergents; D004338:Drug Combinations; D010450:Endopeptidases