Subviral Particles: Prions and Viroids (2B) Practice Test

A comparative microbiology course lab examines two subviral particles. Sample X retains infectivity after RNase and DNase treatment but loses infectivity after strong denaturation that disrupts protein conformation. Sample Y loses infectivity after RNase but is unaffected by protease treatment and shows no detectable protein by mass spectrometry. In host tissue, X is associated with progressive neurodegeneration, while Y is associated with reduced plant vigor and altered gene expression.

Which statement best distinguishes replication/propagation between these subviral particles within cells?

A neurology clinic evaluates subviral particles in patients with progressive ataxia and cognitive decline. Brain biopsy homogenate shows seeding activity in a real-time conversion assay that increases with serial dilution, consistent with self-propagating conformational templating. Treatment with UV light (to damage nucleic acids) does not reduce seeding, but treatment with a chaotropic agent that unfolds proteins abolishes activity. Early pathology shows synaptic loss and gliosis without prominent inflammatory infiltrates.

Which outcome would be expected from prion accumulation in affected brain regions?