title: Purification and characterization of infectious myonecrosis virus of penaeid shrimp.
abstract: The causative agent of myonecrosis affecting cultured Penaeus vannamei in Brazil was demonstrated to be a virus after purification of the agent from infected shrimp tissues. Purified viral particles were injected into specific pathogen-free P. vannamei, resulting in a disease that displayed the same characteristics as those found in the original shrimp used for purification. The virus was named infectious myonecrosis virus (IMNV). The viral particles were icosahedral in shape and 40 nm in diameter, with a buoyant density of 1.366 g ml(-1) in caesium chloride. The genome consisted of a single, double-stranded (dsRNA) molecule of 7560 bp. Sequencing of the viral genome revealed two non-overlapping open reading frames (ORFs). The 5' ORF (ORF 1, nt 136-4953) encoded a putative RNA-binding protein and a capsid protein. The coding region of the RNA-binding protein was located in the first half of ORF 1 and contained a dsRNA-binding motif in the first 60 aa. The second half of ORF 1 encoded a capsid protein, as determined by amino acid sequencing, with a molecular mass of 106 kDa. The 3' ORF (ORF 2, nt 5241-7451) encoded a putative RNA-dependent RNA polymerase (RdRp) with motifs characteristic of totiviruses. Phylogenetic analysis based on the RdRp clustered IMNV with Giardia lamblia virus, a member of the family Totiviridae. Based on these findings, IMNV may be a unique member of the Totiviridae or may represent a new dsRNA virus family that infects invertebrate hosts.
authors.affiliation: Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA.
authors.forename: Bonnie T
authors.initials: BT
authors.lastname: Poulos
authors.affiliation: Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA.
authors.forename: Kathy F J
authors.initials: KFJ
authors.lastname: Tang
authors.affiliation: Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Pantoja
authors.affiliation: UMR 5098, CNRS/IFREMER/UM2, cc080 Place E. Bataillon, 34095 Montpellier Cedex 5, France.
authors.forename: Jean Robert
authors.initials: JR
authors.lastname: Bonami
authors.affiliation: Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA.
authors.forename: Donald V
authors.initials: DV
authors.lastname: Lightner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D033561:Penaeidae / Q000821:virology*; D010802:Phylogeny; D012328:RNA Viruses / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D012330:RNA, Double-Stranded / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D017422:Sequence Analysis, DNA; D019196:Totiviridae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D012330:RNA, Double-Stranded; D012367:RNA, Viral; D012324:RNA-Dependent RNA Polymerase