Autographa californica multiple nucleopolyhedrovirus (AcMNPV) recombinants, namely AcRFP produced by fusion of the red fluorescent protein (RFP) gene with the polyhedrin gene, and a recombinant (pAcUW21-23GFP) carrying the green fluorescent protein (GFP) in its viral envelope, were evaluated for their resistance to inactivation by ultraviolet light. AcRFP recombinants produced incomplete polyhedra with low infectivity for Trichoplusia ni larvae, whereas AcuW21-23GFP produced normal polyhedra with high infectivity. Electron microscopy of AcRFP CL14 showed the incorporation of very few viral particles into polyhedrin matrix protein material. The LC50 for AcuW21-23GFP was 0.10 occlusion bodies/mm2, whereas the LC50 values for several AcRFP recombinants ranged from 20 to 329 occlusion bodies/mm2. When both the RFP and GFP recombinants were exposed to ultraviolet light (UV-B 280–320 nm), the results support the conclusion that these fluorescent proteins afford some protection against its damaging effects.
AcMNPV
Autographa californica multiple nucleopolyhedrovirus
BV
budded virus
CPE
cytopathogenic effect
ECV
extracellular virus
OB
occlusion body
ODV
occlusion derived virus
RFP
red fluorescent protein
GFP
green fluorescent protein
TCID50
tissue culture infective dose at the 50 % level
UV-B
ultraviolet light of 280–320 nm