Abstract
Chemical properties of newly isolated Bombyx densonucleosis virus (BmDNV), Yamanashi isolate (Y-DNV), were found to be different from those of first isolated BmDNV, Inaisolate. The viral DNA of Y-DNV was resolved in an agarose gel electropherogram into two closely migrating bands, DNA I and II. The digests of these DNAs treated with some restriction enzymes differed clearly from each other. In order to clarify this phenomenon, the structure of these DNA molecules was investigated by electron microscopy. Both DNA I and II, which were separated by agarose gel electropherogram, were double-stranded linear molecules, and the length of DNA I was slightly longer. No differences were observed in the electron micrographs on the configuration of the two DNAs. Therefore, ti was confirmed that DNA I and II consist of different base sequences. Since the size of Y-DNV is too small to contain two DNA species (MW : 2.1×106 and 1.7×106 daltons each), it is highly probable that Y-DNV is composed of a mixture of two similar but different DNVs in the silkworm, Bombyx mori.
