FIG 2.

Thermal stability analysis of intact EV1 virions. (A) Fluorescence traces of SYBR green II in the presence of EV1 show a steep increase starting from around 40°C and a midpoint at 51°C (solid line). SYBR green II by itself shows no fluorescence increase as a function of temperature (dashed line). The fluorescence is normalized with respect to the initial fluorescence. (B) EV1 was incubated with SYBR green II at 50°C and 60°C for 3 and 10 min, respectively, and cooled back to 20°C for fluorescence measurement. At 20°C EV1 is not permeable to the dye, whereas temperature-induced genome egress is detected as an increase in fluorescence. The white bars represent the behavior of SYBR green II alone when subjected to the described treatment.