DAO 39:169-176 (2000)  -  doi:10.3354/dao039169

Monodon baculovirus from Australia: ultrastructural observations

J. E. Vickers1,2,*, R. Webb1,3, P. R. Young1,4

1Department of Microbiology, 2Department of Parasitology and 3Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4072, Australia
4Sir Albert Sakzewski Virus Research Centre, Royal Children's Hospital, Herston Rd, Brisbane, Queensland 4006, Australia
*Present address: CSIRO Tropical Agriculture, 120 Meiers Rd, Indooropilly, Queensland 4068, Australia. E-mail:

ABSTRACT: The cytopathology, virogenesis and replication of monodon baculovirus (MBV) in Penaeus monodon from Australia are described. Electron-dense unenveloped nucleocapsids, not previously described for MBV, are shown in the cytoplasm and attached to the nuclear envelope of infected hepatopancreatocytes. These nucleocapsids comprise a missing link in the published literature on the replication cycle of MBV by providing evidence for the means by which the viral genome travels from the plasma membrane of the hepatopancreatocyte to the nucleus. Features similar to those of MBV from other areas, but not previously reported for MBV from Australia include empty capsids attached to the nuclear pore, central filaments in developing capsids, capsids partly filled with nucleic acid, and filaments in subapical envelope expansions. A model for virogenesis and replication is illustrated which takes into account the new observations as well as previously described ultrastructural characteristics of the developing viral particle.

KEY WORDS: Australian MBV · Baculovirus · Viral replication cycle · Electron microscopy

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