Figure 4.

Electron microscopy of SARS-CoV in inoculum, clinical samples, and tissue samples of experimentally infected cynomolgus macaques

A: Negative-contrast electron microscopy of virus stock used to inoculate cynomolgus macaques shows the typical club-shaped surface projections of coronavirus particles; negatively stained with phosphotungstic acid, bar=100 nm. B: Morphologically identical particles isolated from nasal swabs of infected macaques; negatively stained with phosphotungstic acid, bar=100 nm. C: Transmission electron microscopy of infected Vero 118 cell shows viral nucleocapsids with variably electron-dense and electron-lucent cores in smooth-walled vesicles in the cytoplasm; stained with uranyl acetate and lead citrate, bar=500 nm. D: Morphologically similar particles occur in pulmonary lesions of infected macaques, within vesicles of the Golgi apparatus of pneumocytes; stained with uranyl acetate and lead citrate; bar=500 nm.