FIG 8.

Viral morphogenesis: high-pressure freezing/freeze-substitution. Cells were infected with WR, Ets85, or vL4i at an MOI of 10. For Ets85, cells were incubated at 31°C or 39.7°C. For vL4i, cells were incubated at 37°C in the presence or absence of 200 μM IPTG. At 24 h postinfection, cells were processed by high-pressure freezing and freeze-substitution as described in Materials and Methods. Ultrathin sections were visualized in an electron microscope. (A) WR at 31°C. (B) WR at 39.7°C. (C) Ets85 at 31°C. (D) Ets85 at 39.7°C. (E) WR at 37°C. (F) vL4i in the presence of IPTG. (G and H) vL4i in the absence of IPTG. (I) Higher magnification of a wild-type mature particle. (J and K) Higher magnification of mature particles produced in mutant infections under nonpermissive conditions. Arrows and arrowheads indicate mutually perpendicular sections of representative particles in which the nucleocapsid can be visualized. Filled arrow, transverse section (A); open arrow, sagittal section (C); arrowhead, coronal section (F). Scale bars, 500 nm (A to H) and 100 nm (I to K).