• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.1
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• pp.87-91
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• 2003

BmNPV (Bombyx mori nuclear polyhedrosis virus) causes nuclear polyhedrosis in silkworms. The tolerance of silkworms to BmNPV is controlled by polygenes. This paper reports on the relative tolerance of silkworm breeds among the germplasm maintained at Andhra Pradesh State Sericultural Research ＆ Development Institute (APSSRDI), Hindupur, India. The silkworm larvae out of second moult were per orally inoculated with BmNPV polyhedra $(l{\times}l0^{th}//ml)$ and reared upto spinning. The response to BmNPV had been categorized into apparent tolerance, real tolerance and susceptibility. Among the 145 silkworm breeds screened, 18 bivoltines and 16 polyvoltines were found to have real tolerance to BmNPV.

• Journal of Sericultural and Entomological Science
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• v.34 no.2
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• pp.20-25
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• 1992

The location of the polyhedrin gene of Bmbyx mori nuclear polyhedrosis virus(BmNPV) was determined by using a cloned polyhedrin gene from the Autographa californica nuclear polyhedrosis virus(AcNPV) as a hybridization probe. The 7.4 Kb PstⅠ fragment DNA of Bm-NPV was cloned to plasmid pUC19 vector. A fragment containing this gene was mapped and sequenced in its entire polyhedrin reading frame. Nucleotide sequences comparison of the polyhedrin of the BmNPV to that of previously reported by Ⅰatrou(1985) revealed that the sequence varied in 10 base, Comparison of the amino acid sequence of the two structured gene revealed that coding sequence varied 74 valine to isoleucine, 76 aspargine to serine and 155 methionine to valine.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.676-684
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• 1998

Baculovirus transfer and expression vectors with Hyphantria cunea nuclear polyhedrosis virus (HcNPV) were constructed. An initial transfer vector, pHcEV, constructed using HcNPV was previously reported (Park et al. 1993. J. Kor. Soc. Viral. 23: 141-151). Herein, the size of the vector was properly reduced, and a functionally perfect vector was constructed and named pHcEV-IV (6.7 kb). The vector has a 2.2-kb HcNPV DNA sequence in the 5'-flanking region of the vector's polyhedrin gene promoter. The 1.8-kb HcNPV DNA sequence, poly A signal sequence, T3 primer sequence, and 13 multicloning site sequences, in order, were ligated in front of the translation start codon of the polyhedrin gene. The cloning indicating marker lacZ gene was inserted into the pHcEV-IV, named pHcEV-IV-lacZ, and transferred into the wild-type virus. Recombinant expression virus, lacZ-HcNPV, was constructed by replacing the lacZ gene in the pHcEV-IV-lacZ with the polyhedrin gene of the wild-type virus. The recombinant virus was isolated from blue plaques that produce $\beta$-galactosidase without polyhedra. The lacZ gene insertion was confirmed by Southern hybridization analysis. The expression of the lacZ gene in Spodoptera frugiperda cells infected with the lacZ-HcNPV was examined by SDS-PAGE and colorimetric assay. One 116-kDa LacZ protein band appeared on the PAGE. The production rate of the $\beta$-galactosidase was approximately 50 international units (IU) per min per ml between 2 to 5 days postinfection (p.i.). The highest activity occurred at five days p.i. was 170 IU/min/$m\ell$. The enzyme activity first appeared about 20 h p.i. as measured by colorimetric assay.

• Korean journal of applied entomology
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• v.28 no.1
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• pp.10-15
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• 1989

This studies were carried out to selected high pathogenic nuclear polyhedrosis viruses(NPVs) against Pseudaletia(=Leucania) separata for the introduction of microbiol control of the insect NPV in Korea. Among 21 NPVs, Sesamia inferens and 4 P. separata NPV strains were highly pathogenic against P. separata when fed orchard grass leaves smeared virus suspension on the 2nd instar larvae. Three NPV strains (LsNPV-F, LsNPV-G, LsNPV-Y) were more susceptible to the younger instar than the older instar P. separata larvae when fed artificial diet mixed with the virus to the insect.

• Journal of fish pathology
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• v.8 no.1
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• pp.31-36
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• 1995

Hc nuclear polyhedrosis virus DNA genome was digested with EcoRI endonuclease, these partial fragments were recombined into the pUC8 plasmid vector and transformed in E. coli JM 83 cell. The genome DNA has 24 EcoRI fragments and 12 fragments of them were subcloned. The four recombinants were named as eNP-O, eNP-Q, eNP-R and eNP-S. The expression of foregin gene of the recombinants was investigated by analysing protein patterns on the SDS-PAGE. The eNP-O, eNP-Q and eNP-R were expressed a different weight of protein as comparision with potypeptide bands of E. coli JM 83 host cell.

• Applied Microscopy
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• v.11 no.1
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• pp.51-57
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• 1981

The process of the formation of polyhedra occlusion bodies and occlusion of viral nucleocapsids of Autographa californica Nuclear Polyhedrosis Virus in Spodoptera frugiperda cell were photomicrographed and described. Progeny viral nucleocapsids were observed in the nuclei of the host cells, bundled and then enveloped. The nucleoapsids were mainly accumulated near the membrane-like profiles. The nuclear membrane were hypertophied up to the cytoplasmic membrane. Prepolyhedral bodies were observed and they were growing with the accumulations of thread-like materials(polypeptides) produced by viral genes. The bundled and enveloped nucleocapsids were occluded into the growing polyhedra.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.728-732
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• 2000

Propagation of Anagrapha falcifera nuclear polyhedrosis virus(AfNPV) was investigated using well-plates and split-flow air-lift bioreactors. In well-plate experiments, the effects of pH, cell density at a point of infection, serum concentration, DEAE-dextran, and lipid on virus propagation were all closely examined. The AfNPV titer in well-plates was optimal at pH 6.8 and $3{\times}10^6$ cells/$cm^2$. The virus titer was not dramatically affected when the fetal bovine serum concentration was reduced from 10% to 5%. The addition of cholesterol at AfNPV infection of Sf21 cells enhanced the virus titer, whereas the addition of DEAE-dextran did not improve the titer. The AfNPV titer ($3.8{\times}10^7$ $TCID_{50}/ml$) at optimized conditions for well-plate experiments was 2.5-fold higher than for the control. In bioreactor experiments, the AfNPV titer showed its maximum level at air flow rates of 20-40 ml/min. In a split-flow air-lift bioreactor, AfNPV titer ($2.3{\times}10^7\;TCID_{50}/ml$) was 1.5-fold higher than the control when the culture was at pH 6.8 and supplemented with 0.34 mM cholesterol.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.1
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• pp.10-18
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• 2014

Baculoviruses base vectors come to be regarded as methods for in vivo gene delivery and transient expression to the silkworm. In the case of silkworm, B. mori, two types of baculoviruses, AcNPV (Autographa californica nuclear polyhedrosis virus) and BmNPV (Bombyx mori nuclear polyhedrosis virus), are potentially applicable as vectors. Recently, AcNPV showed promising results with some silkworm strains despite different host-specificities. We searched for a highly-permissive silkworm strain in the B. mori stocks of Kyungpook National University that could produce high levels of recombinant protein. Seventy strains were screened using the recombinant AcNPV/BmA3-Luc virus. Based on the measured luciferase activity, the strains could be divided into three groups, high-, middle-, and low-permissive strains, according to their relative recombinant protein expression levels. At 48 hours post-injection, the luciferase activity in the high-permissive strains was 500-fold greater than that of the low-permissive strains. At 72 hours post-injection, a significant elevation in luciferase activity was observed in the hemocytes of all strains. Then, based on the above results, the High Permissive Strain (HPS) S10 and the Low Permissive Strain (LPS) S39 were pick up and was carried out Dot blotting, RT-PCR and Real time PCR.

• The Journal of Korean Society of Virology
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• v.28 no.2
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• pp.129-138
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• 1998

Bovine growth hormone (bGH) gene was expressed in an insect Spodoptera frugiperda cell line using a Baculovirus, Hyphantria cunea nuclear polyhedrosis virus (HcNPV). The bGH gene in pbGH plasmid was sequenced and amplified by PCR technique with two primers containing NcoI sites. The bGH gene consisted of 654 bp (217 amino acid residues), the 5'-untranslated region of the cloned bGH cDNA contains 56 bp, and the 3'-untranslated region contains 145 bp and two pallindromic regions. The amplified bGH gene DNA fragment (654 bp) was inserted into the NcoI site of the pHcEVII vector, which was named pHcbGH. The pHcbGH transfer vector DNA and the wild type HcNPV DNA were cotransfected into S. frugiperda cells to construct a recombinant virus. Eight recombinant viruses were selected and named HcbGH. One clone, HcbGH-4-1 showed largest plaque size, therefore the recombinant virus was further studied. The multiplication pattern of the recombinant HcbGH-4-1 was similar to that of the wild type HcNPV. The bGH gene DNA in the HcbGH-4-1 recombinant was confirmed by Southern blot hybridization. The amount of the bGH (217 amino acid residues, 21 kDa) produced in S. frugiperda cells infected with the HcbGH-4-1 recombinant was approximately 5.5 ng per ml ($10^6$ cells) by radioimmunoassay.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.51-60
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• 1993

The polyhedrin gene-containing DNA fragment of Hyphantria cunea nuclear polyhedrosis virus (HcNPV) was localized by southern hybridization with Autographa california CPA EcoRI-I fragment (7.3 kb), Bombyx mori NPV PatI-F fragment (7 kb) and synthetic oligonucleotide(30-mer) as probes. the PstI-L(5.3 kb) fragment of HcNPV was cloned to E. coli and the plasmid of the fragment was named as pHcP-L(8.0 kb). The pHcP-L was physically mapped and subcloned to E. coli as pHcP-L1(4.7 kb), pHcP-L2(7.1 kb), pHcP-L3(5.3 kb), pHcP-L4(4.2 kb) and pHcP-L5(4.5 kb).