PRNP and scrapie: PrPC was detected in non-infected brain homogenates in equal amounts 40, 80, 120 and 150 days post infection (p.i.)(Figure1A, lanes 1, 3, 5, 7), while total PrP of scrapie-infected brain homogenates slightly increased during infection (Figure1A, lanes 9, 11, 13, 15), caused by the accumulation of PrPSc as demonstrated by proteinase K (PK)-digestion (Figure1A, lanes 10, 12, 14, 16).