Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Negative staining of influenza virus particles. At pH 7.4, virions show well-ordered surface spikes (A); at pH 6.0, spikes are still well-defined (B); after exposure to pH 5.0, virions show a disordered surface (C); at pH 4.0, the spikes appear very discontinuous (D). Inserts show greater detail.
