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Abstract

Abstract. The polyhedrin gene (polh) was identified from the Trichoplusia ni (Tni) single capsid nuclear polyhedrosis virus (SNPV). An EcoRI fragment containing the truncated polyhedrin gene was detected by hybridization with an AcMNPV expression vector probe; the remaining portion of the gene was amplified by reverse PCR. An open reading frame (ORF) of 741 nucleotides (nt), encoding a putative protein of 246 amino acids (a.a) with M r 28,780 Da was identified. The 5 t -noncoding region contained the putative late (TAAG) transcription initiation motif. The 3 t end, downstream of the translation stop codon, lacked an obvious putative poly (A) signal. Nucleotide and amino acid homology are greater than 80% to that of Mamestra brassicae polyhedrin sequences. Results suggest that T. niSNPV is a member of the group II nuclear polyhedrosis viruses. IntroductionThe Family Baculoviridae are invertebrate-specific pathogens that contain a single circular supercoiled double stranded DNA molecule that ranges in size from 80-220 kilobases (1). In excess of 600 insect species are susceptible to baculovirus infection, with a single virus isolate normally restricted to one host or a few closely related species.

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“…6). Gene arrangement and gene homology comparisons con-firmed the earlier speculation that TnSNPV was a Group II NPV [7].…”

“…TnSNPV, a member of the family Baculoviridae, possesses a genome about 160 kb in size. The virus is not well characterized with only the polyhedrin [7], plO [8] and ie-1 [9] genes sequenced and analysed to date. To gain some insight into the reason why the TnSNPV genome is 30 kb larger than AcMNPV, genome libraries are being sequenced and mapped.…”

A Novel Alphabaculovirus from the Soybean Looper, Chrysodeixis includens, that Produces Tetrahedral Occlusion Bodies and Encodes Two Copies of he65

“…In addition to ChinNPV#1, ThorSNPV [34] and the TnSNPV isolate LBIV-4 [43] have been reported to produce OBs with a tetrahedral morphology. ChchNPV and PsinSNPV-IE were shown to produce OBs of a more typical polyhedral morphology [12,44], while the exemplar isolate of TnSNPV [38] and an isolate of TnSNPV from South Africa [45] were not specifically reported to produce tetrahedral OBs. To identify individual polyhedrin amino acid residues associated with a tetrahedral OB morphology, the ChinNPV#1 polyhedrin sequence was aligned with the polyhedrin sequences of ThorSNPV, ChchNPV, PsinSNPV-IE, and three different isolates of TnSNPV for which a complete polyhedrin sequence had been determined.…”