• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.221-227
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• 2004

Protocol was established for production of virus free healthy seeds using meristem ($0.3-0.5\;\cal{mm}$ in size) culture and field management under net house condition in tomato. The isolated meristem was found well established in MS liquid medium containing $0.1\;\cal{mg}\;1^{-1}\;of\;GA_3$. For shoot and root development either from primary meristem or from nodal segment of meristem derived plants, semisolid MS medium having $0.5\;\cal{mg}\;1^{-1}$ of IBA was found most effective. The elimination of the studied viruses (ToMV, CMV, ToLCV) in meristem-derived plants was confirmed by DAS-ELISA test. For field management of the virus eradicated meristem-derived plants, use of net house was found very effective measures to check viral vector visit and eventually infection. The meristem-derived plants were vigor and high yielder than the native seed derived plants and produced healthy seeds. Due to stop vector visit, no viral symptoms were observed in both $R_1\;and\;R_2$ plants cultivated in net house condition. Starting of viral infestation was observed in $R_2$ generation when they were planted in open house condition without control of vector visit. Therefore, for management of viral diseases, use of virus free meristem derived plantlets and their subsequent cultivation in soil under net house condition without using any vector killing insecticide can be recommended for producing healthy seeds in tomato. The developed protocol for environmentally healthy tomato seed production in Bangladesh may be used in the countries having similar tropical like environment conducive for viral vector visit.

• Genomics & Informatics
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• v.20 no.3
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• pp.37.1-37.1
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• 2022

• Korean Journal of Veterinary Service
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• v.19 no.1
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• pp.1-29
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• 1996

This study was conducted to elucidate the pathogenesis of Aujeszky's disease virus(ADV) by histopathologic examination. The first Korean ADV Isolate, which was isolated from piglets with clinical signs of Aujeszky's disease in Yangsan(YS) county, Kyungnam province, was inoculated into 32 days old piglets with a dose of $10^{5.9}$$TCID_{50}/ml$ through intranasal or intramuscular route. These piglets were sacrificed at intervals of every 24hrs for 8 days. The virulence of YS strain was determined by the observation of clinical signs, gross findings, and histopathologic changes in tissues. The virus recovery test was performed from brain, spleen, lung and tonsil in cell culture. The pathogenesis of YS strain was determined by the observation of histopathologlc lesions in CNS and neuronal tracts. The major clinical signs were fever, anorexia, dyspnea, constipation, tremor, ataxia, circling movement, hindleg paralysis and salivation. The clinical signs were more severe in piglets of the group inoculated intranasally than those of the intramuscularly inoculated gorup. Lymphocytopenia was detected on day 5 to day 6 postinoculation (PI). The ADV was recovered from the tissue homogenates of tonsil, lung, spleen and cerebrum in cell culture. The highest virus titer was detected from tonsil between day 6 and day 7 PI. Reddish sublobar consolidation foci were scattered in the apical and cardiac lobes of lung. Although yellowish necrotic foci were detected in tonsil and liver, hemorrhagic lesions were mainly observed in heart, kidney and lymph nodes. Histopathologically, degeneration and necrosis of nerve cells, nonsuppurative meningoe-ncephalitis, nodular gliosis and perivascular cuffings were observed in CNS. Multifocal fibronecrotic foci were observed in lung, liver, lymph nodes and spleen. The major pathologic changes were detected in the midbrain, pons and medulla oblongata. Eosinophilic intranuclear inclusion bodies were mainly observed in epithelia and /or macrophages of tonsil, liver, lung, spleen and submandibular lymph nodes, and neurons of brain, respectively. Observation of viral particles at various stages of replication were possible from the endothelial cells of the alveolar capillaries and tonsillar crypt epithelia by transmission electron microscope.

• ALGAE
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• v.30 no.2
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• pp.81-87
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• 2015

Recent studies have shown the importance of viruses as potential sources of plankton mortality, which affect primary production and biogeochemical functions of their hosts. Here, we report basic characteristics of a novel virus (Stephanopyxis palmeriana virus: SpalV) that causes lysis of a culture of the diatom S. palmeriana, which was isolated in Jaran Bay, Korea, in August 2008. SpalV is a round-shaped viral particle ~25-30 nm in diameter that propagates in its host's cytoplasm. In addition, it shows species-specific infectivity among the tested diatom species. The burst size and latent period are estimated to be roughly 92 infectious units $cell^{-1}$ and <80 h, respectively.

• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.333-341
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• 1996

One of the biggest problems involved in transgenic animal production is lack of appropriate market genes. To overcome this problem, we tested whether the genes of SEAP (secreted alkaline phosphatase) and GFP (green fluorescence protein) on our retrovirus vectors can be applicable to the transgenic animal production. The main advantage of these marker genes over other generally mainpulation can be selected without sacrificing viability. The results obtained in this study are summarized as follows: 1. Removal of zona pellucida from the mouse zygotes did not affect embryo developments to blastocysts. 2. Co-culture of zona-free embryos with virus-producing cells for 6 hours also did not affect embryo developments to blastocysts. 3. Among 58 blastocysts developed from the zona-free zygotes co-cultured with the virus-producing cells, SEAP expression was observed from the 6 blastocysts. 4. Expression of the GFP gene was detected from the virus- producing cells but no embryo expressing the gene was counted among 50 blastocysts developed from the zona-free zygotes co-cultured with the virus-producing cells.

• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.195-199
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• 1991

Infectious pancreatic necrosis(IPN) virus was known as a causative agent of newly recognized viral disease of young rainbow trout characterized by highly contagious, high mortality and necrosis of pancreas. Several strains of IPN viruses were recovered from young rainbow trout that have been shown a typical cinical sign of infectious pancreatic necrosis disease. The field isolate produced cytopathic effect, and multiplied up to $10^{6.0}$ to $10^{6.5}$ $TCID_{50}/0.1ml$ in BT cell culture. In the indirect immunofluorescent assay with trout anti-IPN virus IgG and goat anti-trout IgG FITC conjugate, these isolates were proved to be a IPN virus that were closely related with VR277 strain of IPN virus antigenically.

• BMB Reports
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• v.28 no.3
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• pp.216-220
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• 1995

cDNA for human cholesteryl ester transfer protein (CETP), a potent atherogenic plasma protein that redistributes the neutral lipids among lipoproteins, was expressed in recombinant vaccinia virus-infected cells (CV-1). Two insertion vectors regulated by different promoters were constructed. The vectors were introduced into human thymidine kinase-negative ($TK^-$) 1438 cells infected with wild-type vaccinia virus (WR strain). Recombinant viruses were selected with 5-bromodeoxyuridine (BUdR) and X-gal and identified with DNA dot blot analysis (vSC11-CETP and vTM1-CETP). The CETP cDNA insert in the recombinant vaccinia virus genome was identified by Southern blot analysis. Transcription of CETP cDNA in CV-1 cells infected with recombinant vaccinia virus was monitored by Northern blot analysis using the CETP cDNA as a probe. Positive signals were detected at 1.8 kb in cells infected with vSC11-CETP and at 2.3 kb in cells infected with vTM1-CETP. The recombinant vaccinia virus-infected CV-1 cells were shown to produce functional CETP when the culture medium was subjected to the CETP assay.

• The Korean Journal of Mycology
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• v.20 no.2
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• pp.149-153
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• 1992

This study aimed to investigate possible cause of slow and abnormal growth of oyster mushrooms, Pleurotus florida and P. ostreatus collected from bad crop farms. Spherical virus particles of 30 nm in diameter from P. florida, 23 nm particles from P. ostreatus, and both 23 and 30 nm particles were also found from interspecies mated culture between P. florida and P. osreatus. The virus particles might be associated with the bad crop of Pleurotus species.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.262-269
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• 2005

An antiviral producing bacterial strain was isolated from a ginseng rhizosphere in Kangwon province of Republic of Korea. In order to identify the bacterial strain, microbiological, physiological and biochemical tests were performed, along with RAPD, 16S rRNA, 16S-23S rRNA ITS (intergenic spacer region) and DNA-DNA hybridization analyses. The bacterium was found to be a strain of Pseudomonas fluorescens, which was designated as Gpf01. The strain was grown in Muller-Hinton (MH) broth, and the culture supernatant obtained was filtered through a $0.45{\mu}l$ filter. It was further boiled at $100^{\circ}C$ and tested in two experiments for its ability to control a yellow strain of Cucumber mosaic virus (CMV-Y). In the first experiment, boiled culture filtrate (RCF) was treated on one half of the leaves of Chenopodium amaranticolor followed by CMV- Y inoculation on both halves. In the second experiment, BCF was treated on the lower leaves of Nicotiana tobacum var. Xanthi-nc, with the CMV-Y mechanically inoculated onto the upper untreated leaves. In the first experiment, BCF treatment was able to considerably reduce the number of viral lesion, and in the second experiment, plants treated with BCF showed no visible viral symptoms compared to the Muller-Hinton (MH) media treated controls 15 days post inoculation (dpi), and remained symptomless throughout the study period. Thus, Gpf01, identified as P. fluorescence, was able to produce an antiviral component in the culture filtrate, which was found to be heat stable, non-phytotoxic and effective in local as well as systemic hosts of CMV.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.220-227
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• 2007

Sweetpotato fields in Korea are highly infected with virus and virus like diseases that greatly diminish both yield and quality as indicated by field observations and laboratory tests. In order to solve this problem, there is an urgent need to produce and mass propagate virus-free planting materials for distribution to the farmers. These experiments were conducted, firstly, to determine the most appropriate culture media, nutrient solution, and cutting intervals to maintain growth and vigor of tissue cultured plantleta as mother plants for propagation in insect-proof greenhouse. And as a labor saving method, the production efficiency of plug trays for rapid propagation of stem cuttings as a source of planting materials was likewise evaluated. Results showed that plants grown in medium B supplied with 0.5 and 1.0 strength of MS nutrients had high growth rate, and 20-day cutting interval was the best. 72-plug tray was better than 128-plug. Secondly, it was to develop a technique for the production of first-generation seed roots using hydroponics cultivation system. The yield of virus-free plants propagated in the non-insect proof and open-field cultivation was 2,402 kg/10a, 6% higher than those in the insect-proof cultivation, and the rate of virus re-infection was 18% higher compared to 3.3% with insect-proof cultivation. Lastly, it was to investigate the growth performance of virus free plants in farmers' field. Differences were existed in the yield depending on the variety used, but virus free plants showed an increase of $6{\sim}24%$ over virus infected plants.