Biological and biochemical investigations on five European isolates of Mamestra brassica nuclear polyhedrosis virus.

Five multiply enveloped European isolates of Mamestra brassicae nuclear polyhedrosis virus (Oxford, German, French, Dutch and Danish) were found to be very closely related serologically using the enzyme linked immunosorbent assay (ELISA) double antibody sandwich method and immunodiffusion. By SDS-polyacrylamide gel electrophoresis of viral proteins and restriction endonuclease analysis of DNA using seven enzymes there appeared to be two variants as the Oxford and German isolates were distinct from the other three. The German isolate was shown to be more susceptible to Nonidet P40 detergent treatment affecting some nucleocapsid structural polypeptides which also reduced antigenicity in gel immunodiffusion plates. In bioassays of polyhedra, the Dutch isolate showed a higher LD50 than the other viruses although this was not statistically significant.