Heat Stability of Native PRSV Coat Protein in Plant Host
Matrix. In experiments to test the effect of heat intensity and
duration on PRSV CP stability, we observed a significant loss of
signal in Western blots utilizing a PRSV CP specific antibody
when crude leaf extracts of PRSV from infected papaya were
treated at 100 C for 2 h. Residual amounts of CP were observed
in the sample treated at 100 C for 4 h, whereas no bands were
detected when the sample was treated at 206 C for as short as
20 min. The multiple bands observed using the PRSV CP
antibody, the highest of which correlated in size to the full-length
PRSV CP (∼36 kDa), are attributed to degradation products in
the context of crude plant extracts as they were only detected
in extracts from infected leaves, but not in extracts from the
noninfected control. The higher molecular mass band corre-
sponding to the full-length CP seemed to degrade faster than
the proteins running as smaller molecular mass bands. This phe-
nomenon was also observed using other treatments