• Korean journal of applied entomology
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• v.55 no.2
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• pp.81-89
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• 2016

Double-stranded RNA (dsRNA) has been applied to control insect pests by its suppressive activity against specific target genes. Integrin is a heterodimer (${\alpha}$ and ${\beta}$) transmembrane protein and plays a critical role in cell-to-cell or cell-to-extracellular matrix interactions in eukaryotes. Suppression of ${\beta}$ subunit integrin gene expression by its specific dsRNA (= dsINT) induces significant mortality against target insects. Furthermore, a recombinant bacterium expressing dsINT is potent to kill target insects. However, it is necessary to develop a formulation technique of the dsRNA-expressing bacteria to apply the bacterial insecticide against field populations. This study formulated the recombinant bacteria by freeze-drying and tested its control efficacy against target insects. The formulation maintained significant insecticidal activity against last instar larvae of Spodoptera exigua. While a commercial Bacillus thuringiensis (Bt) insecticide exhibited only about 60% insecticidal activity against S. exigua last instar, an addition of the dsINT-expressing bacterial formulation significantly enhanced the Bt insecticidal activity. The dsINT-expressing bacterial formulation exhibited relative selectivity to target insects depending on sequence similarity. These results indicate that a freeze-dried form of dsRNA-expressing bacteria keeps its insecticidal activity.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.471-488
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• 2019

Random genes were screened in two transforming ways to investigate the new genes of a ladybug using the Harmonia axyridis cDNA library stock cell cloned in the LITMUS 28i vector in a previous study. Phenotypic variation was observed after injection of the synthesized double-stranded RNA through the in vitro transcription process. The cDNA library of H. axyridis was transformed into E. coli $DH5{\alpha}$ and 10B competent cells by heat shock. Analysis of the nucleotide sequences of the 42 clones with the insert DNAs revealed that 21 clones were homologous with the genes of insects, and only one clone had a gene from H. axyridis. Thirteen of the 21 insect genes were homologous with genes from coleopteran insects. Fourteen genes were selected, which were identified by the gene screening results, and were synthesized as double-stranded RNA through in vitro transcription. One microgram of the synthesized double-stranded RNA between segments T1 and T2 were injected using a syringe into each anesthetized fourth larvae which were under 2 days old. As a result, a phenotypic variation appeared in the larva injected with the two genes. While the eggs of H. axyridis injected with distilled water hatched out three days after oviposition, the eggs of H. axyridis injected with dsHma 06 did not hatch but become shrivel a week after oviposition. Most of the H. axyridis injected with dsHma 08 died and were unable to complete the pupation or eclosion during ecdysis.

• Journal of Mushroom
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• v.8 no.2
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• pp.41-50
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• 2010

Mycoviruses have been found in many fungal species including mushrooms. Double-stranded (ds) RNA genomes were common type in mycoviruses, but single-stranded (ss) RNA mycoviruses were also reported in some fungal species. Sequencing analysis using cDNA cloning experiments revealed that mycoviruses can be classified into several different virus families such as Totiviridae, Hypoviridae, Partitiviridae and Barnaviridae etc. Because the nucleotide sequence data that are available in these days are very limited in a number of mycoviruses, the existence of more diverse viral groups in fungi are currently expected. In this review, we selected four different fungal groups, which were considered as the model systems for mycovirus related studies in both plant pathogenic fungi and edible mushroom species, and discussed about their molecular characteristics of diverse mycoviruses. The plant pathogenic fungi introduced here were Cryphonectria parasitica and Helminthosporium victoriae and the edible mushroom species were Agaricus bisporus and Pleurotus ostreatus.

• The Microorganisms and Industry
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• v.16 no.2
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• pp.10-13
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• 1990

Fungal Virus에 대한 연구는 60년대말 double-stranded RNA(dsRNA)가 interferon의 생성을 촉진시킨다는 보고가 나온 이후 dsRNA를 많이 얻을수 있는 재료로써 이 virus에 대한 연구가 본격적으로 진행되었다. 현재까지 60여종 이상의 genus와 200가지 이상의 species에서 virus의 존재가 분리 또는 확인되어 있다. 여기서는 Ustilago maydis의 killer activity를 유발하는 virus에 대한 일반적인 특징과 이 virus의 transcription 과정에 대해 설명하고자 한다.

• Journal of the Korean Chemical Society
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• v.65 no.2
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• pp.121-124
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• 2021

RNA molecules which bind to the G-rich sequence in the 5'-UTR RNA which plays an important role in expression of N-ras, were selected. The secondary structures of five selected RNA aptamers including primer sequence were found by the CLC RNA workbench ver. 4.2 program (www.clcbio.com) and investigated with RNA structural probes such as RNase T1 which has specificity for a G in single-stranded region, RNase V1 specific for double strand and nuclease S1 specific for single strand. The generalized secondary structure model was proposed and characterized. It was composed of a central long double strand region flanked by single strand region at both end sides. The double strand region had an internal single-strand region and bulges. The single strand loop in the right side was composed of four or five nucleotides.

• Journal of Microbiology
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• v.34 no.1
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• pp.61-67
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• 1996

Double-stranded RNA (dsRNA) viruses and single-stranded RNA(ssRNA) viruses were detected in a strain of Pleurotus mushroom cultivated in a farm. Those fungal virsus were purified in the pH 6.0 or pH 7.2 using CsCI or Cs$_{2}$SO$_{4}$ buoyant density centrifugation. Each viral particles were not completely separated at any trials. However, mushroom bacili-form virus contains a single major nucleic acid with 0.7 Kb ssRNA, which might code for 20 Kd viral capsid protein. The dsRNAs are encapsidatred into spherical-form viruses, whereas ssRNA viral genomes are encapsidated into two different sizes of bacili-form particles. A healthy-looking mushroom also contained some spherical-form viruses with dsRNAs. Laboratory strains of Pleurotus ostreatus and a cultivated strain of P. sajor-caju did not show any viral particles. Mushrooms with specific disease symptoms. however, contained at least four different sizes of spherical-form viruses. Thus, we concluded that a bacilli-form virus case a severe disease symptoms of adnormal on mushroom development.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.361-363
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• 1996

The terminal regions of the double-stranded RNA (dsRNA) genome segments of infectious pancreatic necrosis virus (IPNV) DRT strain were sequenced. The dsRNAs, which were $^{32}P$-labelled at their 3'-termini by incubation with [$^{32}P$]pCp and T4 RNA ligase, were separated by 5$%$ polyacrylamide gel electrophoresis, and the segments A and B of IPNV-DRT were sequenced by two-dimensional gel electrophoresis. The 5'-terminal sequences of the IPNV-DRT plus strand from two genome segments were found to have the same conserved nucleotide (5'-CGG(C/A)A-), but the 3'-terminal sequences -CCCCAGGCG-3' and -CGGACCCCG-3' were found in the plus strand from segments A and B, respectively. The inverted oligonucleotide sequences of 3'-terminal of between segments A and B were found and they differ from those of other IPNVs.

• Korean Journal of Microbiology
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• v.45 no.3
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• pp.239-245
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• 2009

Translation initiation factor eIF1A performs essential functions in various initiation steps including 43S preinitiation complex formation in eukaryotes, and contains a highly conserved oligonucleotide-binding (OB) fold. In our previous study, we discovered that eIF1A possesses RNA annealing activity and forms a stable complex with double-stranded RNA. In this study, we initiated site-directed mutations in eIF1A to find the active sites for these biochemical activities and to investigate whether they are essential functions for yeast cell growth. A truncated protein, eIF1A($\Delta$T), devoid of both N- and C-terminal domains but containing an intact OB-fold exhibited RNA annealing activity. In contrast, all point mutations in OB-fold domain, except R57D, impaired both RNA annealing and dsRNA binding activities, indicating that the intact OB-fold domain is required for both activities. Viabilities of the mutant yeast cells were not correlated with RNA annealing activity but with the in vivo protein stabilities in the case of R57D and K94D.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.225.1-225
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• 1999

No Abstract, See Full Text

• The Korean Journal of Mycology
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• v.20 no.3
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• pp.234-239
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• 1992

The experiment was performed to find out the possibilities to detect virus infection in oyster mushrooms, Pleurotus species by analysis of doublestranded ribonucleic acid (ds RNA). Ds RNA segments were extracted from virus infected isolates which grew abnormally. But virus free isolates didn't show any ds RNA segments. The ds RNA was consisted of one large segment of 8100 base pairs (bp) and 4 smaller segments with 2170, 2120, 1980 and 1984 bp. Whereas, cell free virus particles showed only one larger ds RNA segment. The ds RNA was dissolved by RNase A in low salt, 0.1 M SSC and melted at $85^{\circ}C$. It was possible to use the ds RNA analysis for detecting virus infection directly from the host cells.