PRELIMINARY CHARACTERIZATION AND PARTIAL CLONING OF THE GENOME OF A BACULOVIRUS FROM PENAEUS-MONODON (PMSNPV = MBV)

Monodon baculovirus (MBV), an occluded virus related to the Baculoviridae, which is enzootic in Southeast Asia in both with and farmed Penaeus monodon populations, was isolated and purified. Virions were rod-shaped, enveloped, 265 to 282 nm in length and 68 to 77 nm in diameter, with unique appendages at each extremity. Singly enveloped nucleocapsids were 250 to 269 nm in length and 62 to 68 nm in diameter, showed a 'cross-hatched' surface appearance, and a double-layered 'cap' structure closing its ends. Subunits of the occlusion body were 22 to 23 nm in diameter and had an icosahedral-like shape. These subunits (polyhedrins) exhibited at least 1 major polypeptide of 58 kDa by SDS-PAGE. The extracted nucleic acid was a very large supercoiled molecule, as shown by electron microscopy, and was demonstrated to be DNA by restriction enzyme digestion. BdmHI restriction fragments obtained after agarose gel electrophoresis were separately cloned in the system pUC18-DH5alpha. Subsequently, restriction maps were established for the inserts, which ranged from 8.5 to 2.8 kbp (kilo base pairs) corresponding to the cloned BamHI restriction fragments. By its characteristics, we propose to include this virus in the subgroup A, subtype SNPV of the Baculoviridae family, and to name it PmSNPV according to the guidelines set forth by the International Committee on Taxonomy of Viruses.