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 Baculoviri dae, which is enzootic in Southeast Asia in both with and farmed Penae us monodon populations, was isolated and purified. Virions were rod-sh aped, enveloped, 265 to 282 nm in length and 68 to 77 nm in diameter, with unique appendages at each extremity. Singly enveloped nucleocapsi ds 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' structu re closing its ends. Subunits of the occlusion body were 22 to 23 nm i n diameter and had an icosahedral-like shape. These subunits (polyhedr ins) exhibited at least 1 major polypeptide of 58 kDa by SDS-PAGE. The extracted nucleic acid was a very large supercoiled molecule, as show n by electron microscopy, and was demonstrated to be DNA by restrictio n enzyme digestion. BdmHI restriction fragments obtained after agarose gel electrophoresis were separately cloned in the system pUC18-DH5alp ha. Subsequently, restriction maps were established for the inserts, w hich ranged from 8.5 to 2.8 kbp (kilo base pairs) corresponding to the cloned BamHI restriction fragments. By its characteristics, we propos e to include this virus in the subgroup A, subtype SNPV of the Baculov iridae family, and to name it PmSNPV according to the guidelines set f orth by the International Committee on Taxonomy of Viruses.