Physico-chemical and substructural studies on Nudaurelia capensis β virus

Abstract

From Introduction: The pine emperor moth, Nudaurelia cytherea capensis Stoll is an insect which, during the larval stage, causes extensive defoliation of the pine tree, Pinus radiata in the Cape province. These insects are susceptible to a virus disease, which on occasions causes large scale mortality. Five nonoccluded viruses have been shown to infect the pine emperor moth, and of these, one found in the greatest concentration, Nudaurelia capensis β virus (NβV) has been characterised to the greatest extent. This virus has been shown to contain RNA, to be isometric with a diameter of 36 mm, and to have a molecular weight of 16 million. The virus occurs in all stages of the insect's development, and by fluorescent antibody staining has been shown to develop in the cytoplasm of the host's cells. There have in recent years been a number of reports describing nonoccluded RNA viruses which appear to be similar to NβV. These are the viruses isolated from the moths Gonometa podocarpi and Antheraea eucalypti, and the one from the citrus red mite, Panonychus citri. These viruses have not been as extensively characterised as NβV, so the extent of the similarity between them and NβV is not known. However it would appear as if their discovery collectively heralds the emergence of a distinct new grouping within the nonoccluded RNA viruses of insects. This work reports the isolation and further characterisation of N. capensis β virus, its protein and nucleic acid.