FIG 6.

Contact with copper surfaces affects virus morphology. (A) Untreated virus. The uneven surface suggests that some damage has occurred to the outer capsid, resulting in a diameter slightly larger than 40 nm being reported for individual virions and disrupting the icosahedral symmetry. Plaque assay of this preparation suggests that the virus is still infectious, so the genome is still able to replicate. This demonstrates the protective nature of the capsid and its role in MNV persistence. (B and C) MNV recovered from stainless steel was observed as scattered individual particles (B) or large clumps (C) that had some damage to the outer capsid. Viral clumping may protect the inner virus particles from desiccation and explain the persistence on this material. (D) In contrast, exposure to copper resulted in viral fragments that were beyond the resolution of the TEM. Bar, 200 nm.