• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.134-134
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• 2017

Recently, host-induced gene silencing (HIGS) system has been successfully applied into development of resistant crops against insects, fungal and viral pathogens. To test HIGS-mediated resistance in rice against rice blast fungus, Magnaporthe oryzae, we first tested possibility of movement of small non-coding RNA from rice cells to rice blast fungus. The rice blast fungus expressing GFP transgene were inoculated to transgenic rice plants ectopically expressing dsRNAi construct targeting fungal GFP gene. Expression of dsRNAi construct for GFP gene in transgenic plants significantly suppressed GFP expression in infected fungal cells indicating that small RNAs generated in plant cells can move into infected fungal cells and efficiently suppress the expression of fungal GFP gene. Consistent with these results, expression of dsRNAi constructs against 3 fungal pathogenic genes of M. oryzae in transgenic rice specifically and efficiently suppressed not only the expression of fungal pathogenic genes, but also fungal infection. The conidia of M. oryzae applied on leaf sheath of transgenic rice expressing dsRNAs against 3 fungal pathogenic genes showed abnormal development of primary hyphae and malfunction of appressorium, which is consistent with the phenotypes of corresponding fungal knock-out mutants. Taken these results together, here, we suggest a novel strategy for development of antifungal crops by means of HIGS system.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.401-408
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• 2012

Initial subcellular responses in susceptible (PI 274420) and resistant (cv. Hartwig) soybeans infected with the soybean cyst nematode (SCN) were examined 2 and 4 days after inoculation (DAI). Subcellular features common to both soybeans at 2 DAI included hypertrophied initial syncytial cells (ISCs) and syncytium-component cells (SCs) with a dense cytoplasm containing proliferated rough and smooth endoplasmic reticulum (RER and SER), a hypertrophied nucleolus, and reduced vacuoles, suggesting that the nematode-infected cells were dedifferentiated. In the resistant soybean, a striking initial subcellular difference from the susceptible soybean was the dilation of the RER, indicating ER dysfunction and leading to cell death. This disturbed nematode feeding, as evidenced by disrupted feeding tubes. In PI 274420, the ISC cytoplasm was depleted, with the exception of ER membranes, at 4 DAI, while the SC cytoplasm was dense with proliferation of starch-containing plastids around multiple nuclei that might be derived from the congregation of nuclei in the neighboring SCs and in part by nuclear division without cytokinesis. In cv. Hartwig, syncytia were necrotized with secondary cell wall thickening outside the plasma membrane and an extremely dense cytoplasm containing a nucleus with an electron-lucent nucleolus, accompanied by the proliferation of closely stacked parallel RER and ribosomes. These results suggest that syncytia develop continuously in PI 274420 to produce and store nutritional substances in SCs, providing for the nematode through ISC until maturation, but in cv. Hartwig, syncytia degenerate early due to excessive metabolism, blocking nematode feeding and cytoplasmic connections with adjacent intact cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.53-58
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• 2000

Treatment of oral cancers with chemotherapeutic agents are evaluated as an effective method for remission to reduce cancer proliferation nowadays. But, minimization of side-effects such as bone marrow suppression, gastrointestinal toxicity and renal damage is another problem to be solved. Thus, a possible approach to develop a clinically applicable chemotherapeutic agents is to screen anticancer activity among traditional medicinal plants which have been used for thousands of years with very low side-effects in orient. In this study we focused on screening anti-oral cancer activities among 14 traditional medicinal plant extracts that revealed anticancer activities on other solid tumors. The results were as follow : 1. Methanol extract of Lepidium apetalum showed the highest anti-oral cancer activity against A253 cells. At concentration of $4{\mu}g/ml$, the cell viability was 48% under our experimental condition. $IC_{50}$ value obtained was $4{\mu}g/ml$. 2. Methanol extract of Coptis japonica and Solanum nigrum were effective on KB cells. Cell viability observed were 62% and 67% at concentration of $4{\mu}g/ml$, and $IC_{50}$ values were $12{\mu}g/ml$ and $10{\mu}g/ml$ respectively. 3. When the methanol extract of Lonicera caerule was combined with $2{\mu}g/ml$ of cisplatin, the anticancer activity was synergistically increased. One hundred ${\mu}g/ml$ of Lonicera caerule showed 92%(alone) or 59%(combined with cisplatin) cell viabilities. $IC_{50}$ value of Lonicera caerule extract against KB cells was reduced from $301{\mu}g/ml$ to $126{\mu}g/ml$ when combined with $2{\mu}g/ml$ of cisplatin. 4. Medicinal plant extracts effective on both A253 and KB cells were Coptis japonica, Lepidium apetalum, Solanum nigrum, Caesalpiniae Lignum, Curcuma aromatica.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.118-118
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• 2022

Carex pumila Thunb. is a plant native to East Asia, Australia, and New Zealand. However, its effect on skin melanogenesis has not been investigated. In the present study, we evaluated its anti-melanogenic properties using B16F10 melanoma cells and zebrafish larvae in the presence or absence of α-melanocyte stimulating hormone (α-MSH). In this study we revealed that concentrations below 50 µg/mL did not induce any cytotoxicity in B16F10 melanoma cells and cardiotoxicity in zebrafish larvae. However, 50 µg/mL treatment significantly inhibited α-MSH-induced extracellular (from 181.24% α 0.62% to 105.15% α 0.31%) and intracellular melanin contents (from 119.8% α 1.2% to 53.4% α 1.7%) as well as intracellular tyrosinase activity (from 143.9% α 4.2% to 103.7% α 1.4%) in B16F10 melanoma cells. At 25 µg/mL and 50 µg/mL concentrations, it could significantly inhibit α-MSH induced hyperpigmentation in zebrafish larvae (from 100% α 2.3% to 60.7% α 1.3% and 47.5% α 1.9% respectively). Additionally, the extract suppressed α-MSH-induced cAMP-CREB-MITF signaling pathway and consequently inhibited tyrosinase expression in B16F10 melanoma cells. In conclusion, our results indicate that this plant extract could suppress the cAMP-CREB-MITF axis which consequently inhibits tyrosinase mediated melanogenesis.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.323-327
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• 1995

This experiment was carried out to observe the origin and developmental pattern of somatic embryos of Oenanthe javanica ($B^{L}.$) DC. The experiment included observation of embryogenic cells and their development stages by light microscope, transmission electron microscope and scanning electron microscope. The embryogenic cells, which were smaller than non-embryogenic cells in size with expanded nucleus and dense cytoplasm. When stained with hematoxylin, the embryogenic cells were readily distinguished from the non-embryogenic cells of which cell walls were stained with safranin. It was observed at somatic embryos developed from single cells on the epidermis of developing embryos or in the surface or inside of embryogenic clumps by segmentation pattern. Observation with a transmission electron microscope revealed that the embryogenic cells had dense cytoplasm expanded nucleus, small vacuoles, large amyloplasts containing starch grains, and abundant organelles including lipid bodies. Under a scanning electron microscope, embryogenic callus was shown to consist of very smaller cells than non-embryogenic cells in an orderly arrangement and covered with a net-like structure, while the non-embryogenic callus consisted of large cells, irregular in size and arrangement, and covered with a gelatin-like material.

• Molecules and Cells
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• v.20 no.2
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• pp.303-303
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• 2005

• Journal of Plant Biotechnology
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• v.4 no.3
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• pp.91-94
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• 2002

An efficient molecular breeding technique for coffee plants was developed. In order to produce transgenic coffee plants, we established a model transformation procedure via Agrobacterium method. We isolated a gene encoding a protein possessing 7-methylxanthine methyltransferase (theobromine synthase) activity, and it was designated as Coffea arabica 7-methylxanthine methyl transferase; CaMXMT. Using this clone, we produced transgenic coffee plants, in which the expression of CaMXMT is suppressed by double-stranded RNA interference (RNAi) andlor anti-sense methods. The expression pattern of CaMXMT was analyzed by reverse transcription-PCR method and we found that, in the transformed cell lines, the level of transcripts were obviously suppressed by RNAi. The endogenous level of caffeine in the transformed cells was dramatically reduced in comparison with non-transformed cells.

• The Plant Pathology Journal
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• v.34 no.3
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• pp.191-198
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• 2018

Fast and accurate diagnosis is needed to eradicate and manage economically important and invasive diseases like fire blight. Loop-mediated isothermal amplification (LAMP) is known as the best on-site diagnostic, because it is fast, highly specific to a target, and less sensitive to inhibitors in samples. In this study, LAMP assay that gives more consistent results for on-site diagnosis of fire blight than the previous developed LAMP assays was developed. Primers for new LAMP assay (named as DS-LAMP) were designed from a histidine-tRNA ligase gene (EAMY_RS32025) of E. amylovora CFBP1430 genome. The DS-LAMP amplified DNA (positive detection) only from genomic DNA of E. amylovora strains, not from either E. pyrifoliae (causing black shoot blight) or from Pseudomonas syringae pv. syringae (causing shoot blight on apple trees). The detection limit of DS-LAMP was 10 cells per LAMP reaction, equivalent to $10^4$ cells per ml of the sample extract. DS-LAMP successfully diagnosed the pathogens on four fire-blight infected apple and pear orchards. In addition, it could distinguish black shoot blight from fire blight. The $B{\ddot{u}}hlmann$-LAMP, developed previously for on-site diagnosis of fire blight, did not give consistent results for specificity to E. amylovora and on-site diagnosis; it gave positive reactions to three strains of E. pyrifoliae and two strains of P. syringae pv. syringae. It also, gave positive reactions to some healthy sample extracts. DS-LAMP, developed in this study, would give more accurate on-site diagnosis of fire blight, especially in the Republic of Korea, where fire blight and black shoot blight coexist.

• Journal of Plant Biotechnology
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• v.2 no.3
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• pp.135-142
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• 2000

The activity of promoter sequences was evaluated in garlic cells using the $\beta$-glucuronidase (GUS) gene as a reporter. Histochemical GUS assay indicated transient GUS activity in leaf, callus and root cells 48 hours after particle bombardment transformation. Quantitative fluorometric assays in extracts of transformed leaves demonstrated that the CsVMV promoter induced the highest level of gene expression, which was, on average, ten fold the level induced by CaMV35S and by the Arabidopsis Act2 promoters and two fold the level expression observed with a construct containing a double CaMV35S plus the untranslated leader sequence from AMV. No activity or very low levels were observed when cells were transformed with plasmids rontaining the typical monocot promoters, Actl, from rice or the Ubi-1, from maize. The green fluorescent protein (GFP) was also tested as a marker gene for garlic transformation. Intense fluorescence was observed in leaf, callus and root cells transformed with a construct containing the gfp gene under control of the CaMV35 Promoter. No fluorescence was detected when the gfp was under control of the Ubi-1 promoter.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.593-600
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• 2014

Osteoporosis is a progressive bone disease characterized by low bone mass which is caused by disturbance in the balance between the activities of osteoblasts and osteoclasts. Postmenopausal osteoporosis is one of the most common disorders in women after menopause, which is linked to an estrogen deficiency and characterized by an excessive loss of trabecular bone. Rubus coreanus has been used for their various pharmacological properties in Asia as a traditional medicine. To investigate the effect of unripe fruits of R. coreanus 30% ethanol extract (RCE) on osteoblast-like cells (MG63) differentiation, we examined the effects of RCE on in vitro osteoblastic differentiation markers, alkaline phosphatase (ALP) activity and receptor activator of nuclear factor ${\kappa}$-B ligand (RANKL) and osteoprotegerin (OPG) expression. The high concentration (50 and $100{\mu}g/mL$) of RCE markedly increased ALP activity, whereas decreased the RANKL/OPG. We also investigated the effect of RCE on M-CSF plus RANKL-induced differentiation of pre-osteoclast cells (RAW 264.7). RCE treatment remarkably inhibited M-CSF/RANKL-induced formation of osteoclast-like multinuclear cells from RAW 264.7 cells. Moreover, the inhibitory effect of RCE was reduced by selective estrogen receptor-${\alpha}$ antagonist. Our research suggests that suggested that unripe fruits of R. coreanus may act beneficial effects on bone mass by regulating both osteoblast and osteoclast.