Fig. 4.
Transmission electron microscopy of cells infected with parental and mutant viruses. BS-C-1 cells were infected with CPXV 91/3 (A, B), ΔA26 (C, D) and ΔATI (E, F) for 18 h and thin sections were imaged by transmission electron microscopy. Abbreviations: MV, mature virion; IV, immature virion; Nu, IV with a nucleoid; c, crescent; N, nucleus. Magnifications are indicated at the bottom of each panel.