Ultrastructural Characterization of Pandemic (H1N1) 2009 Virus
Figure 1. Electron microscopy of pandemic (H1N1) 2009 virus. A) Negatively stained virions grown in MDCK cells showing spherical particles with distinct surface projections. Scale bar = 100 nm. B) Filamentous and ovoid particles assembling at the plasma membrane. Scale bar = 100 nm. C) Extracellular particles showing internal nucleocapsids, seen in cross-section, surrounded by an envelope with prominent spikes. Note all 8 nucleocapsids present in 1 virion (arrow). Scale bar = 100 nm. D) Dense tubules (arrow), which were found in the nuclei of some MDCK-infected cells. Arrowhead, nuclear envelope. Scale bar = 100 nm. E) Immunogold labeling of the nuclear tubules by using an antibody against the matrix protein. Scale bar = 100 nm.