Characterization of the nuclear polyhedrosis virus DNA of Adoxophyes orana and of Barathra brassicae

Abstract

Circular double-stranded DNA was isolated from nuclear polyhedrosis virus (NPV) of Adoxophyes orana (virus particles singly embedded in the polyhedral matrix) and NPV of Barathra brassicae (virus particles multiply embedded in the polyhedral matrix), and some of their physical properties were determined. The molecular weights of A. orana and B. brassicae NPV-DNA, 6.7 x 107 and 8.9 x 107, respectively, were determined by electron microscopy and by renaturation kinetics analysis. The latter analysis also showed that both genomes do not contain repetitive sequences. Absence of homology between DNA of these two viruses was shown by competition hybridization of A. orana NPV-DNA with B. brassicae NPV-DNA. Analysis of these DNAs with the restriction endonuclease EcoRI confirmed that they are different. The buoyant densities in CsCl of A. orana NPV-DNA and of B. brassicae NPV-DNA, 1.694 and 1.696 g/cm3, respectively, are consistent with (G + C) contents of 34.5 and 37%, respectively, as determined by thermal denaturation.