• The Plant Pathology Journal
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• v.28 no.3
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• pp.227-238
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• 2012

Mitogen-activated protein kinase (MAPK) cascades are conserved signaling modules in the eukaryotic cells. They are involved in many major cell processes in fungi such as stress responses, vegetative growth, pathogenicity, secondary metabolism and cell wall integrity. In this review, we summarized the advances of research on the MAPK signaling pathways in Alternaria species. As major phytopathogenic fungi, Alternaria species reduce crop production. In contrast to the five MAPK pathways known in yeast, only three MAPK pathways as Fus3/Kss1-type, Hog1-type, and Slt2-type have been characterized in Alternaria. The Fus3/Kss1-type MAPK pathway participates in regulation of vegetative growth, conidiation, production of some cell-wall-degrading enzymes and pathogenicity. The Hog1-type pathway is involved in osmotic and oxidative stress, fungicides susceptibility and pathogenicity. The Slt2-type MAP kinases play an important role on maintaining cell wall integrity, pathogenicity and conidiation. Although recent advances on the MAPK pathways in Alternaria spp. reveal many important features on the pathogenicity, there are many unsolved problems regarding to the unknown MAP kinase cascade components and network among other major signal transduction. Considering the economic loss induced by Alternaria spp., more researches on the MAPK pathways will need to control the Alternaria diseases.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.219-222
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• 1999

To induce adventitious buds, hypocotyl and cotyledonary explants from 7 to 10 day-old seedlings of lettuce (Lactuca sativa L.: two Japanese cultivars of crisphead lettuce and four Korean cultivars of leaf lettuce) were cultured or Murashige and Skoog (MS) and Schenk and Hildebrandt (SH) media supplemented with BA and NAA in the light for five weeks. Cotyledonary explants produced adventitious shoots at greater frequencies than hypocotyl explants. MS medium was more favorable to adventitious shoot formation than HS medium. Combination of 0.5 mg/L BA and 0.1 to 1 mg/L HPh in MS medium led to the greatest frequency (86%) in adventitious shoot formation. Creator than 95% of shoots excised from explants were rooted when cultured on MS basal medium.

• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.83-91
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• 1994

Stem tissues of tomato plants (cv. Kwanyang) inoculated with Phytophthora capsici were examined by light and electron microscopy to compare early cytological differences between comaptible and incompatible interactions of tomatoes with the fungus. Twenty four hours after inoculation, the compatible isolate S 197 colonized severely the epidermis, cortex, and xylem vessels of stem tissue, whereas only few fungal cells colonized the stem tissues inoculated with the incompatible isolate CBS 178.26. Fragmented plasma membrane, distorted chloroplast, degraded cell wall, remnants of host cytoplasm were early ultrastructural features of the damaged host cell observed both in the compatible and incompatible interaction, a number of vesicles were distributed in the space between fungal cell walls and plasma membrane. The degradation of host cell walls by P. capsici was more pronounced in the compatible than the incompatible interactions. The incompatible interactions of tomato cells with P. capsici were characterized by formation of host cell wall apposition in the cortical parenchyma cells, indicating that the apposition of electron-dense material from the host cell walls may function as a plant defense reaction to the fungus. The fungal cells encased by wall appositions had abnormal cytoplasm and separated plasma membranes. The haustorium which formed from the fungal hyphae did not further penetrate through the host wall apposition and cytoplasmic aggregation, especially in the incompatible reactions. In contrast, the haustorium of the compatible isolate S 197 was not encased by wall appositions.

• Korean Journal of Plant Resources
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• v.31 no.6
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• pp.604-611
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• 2018

This study was conducted to explore the immune activity, anticancer activity and nitrile scavenging activities of methanol extracts from the various organs of four Korean resource plants. The immune responses from both human T and B cell line was significantly enhanced in the cell growth compared to control while the cell growth was influenced at a certain period of culture. The results revealed that the cell growth of both human T and B cell was altered in a time dependent manner. Among tested several resource plants, the flower extract of E. japonicum demonstrated a pronounced cytotoxicity against HCT-116 cell with an IC50 value $132.08{\mu}g\;ml-1$. The flower extract from Corylopsis coreana had a promising scavenging activity against pH 1.2 compared to other species. Taken together, the studied resource plants have influenced significantly in response to immunity and also have the potential cytotoxicity and nitric scavenging activities. However, the species E. japonicum exhibited the pronounced activities from several resource plants. The result from this investigation suggests that the extracts of studied resource plant could be an addition to basic medicine for some diseases.

• Journal of Plant Biology
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• v.32 no.3
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• pp.151-162
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• 1989

Secretory ducts in the stem of Panax ginseng seedlings are observed with light and electron microscopes to clarify development of the epithelial cells of secretory ducts. Secretory duct initial cell is developed from procambial cell which originated from initial cell is differentiated into ipithelial cell ofsecretory ducts. Intercellular space between the epithelial cells are gradually expanded and differentiated into duct lumen. Disintegrations of epithelial cells occur throughout all the stages of development. The cytoplasm of epithelial cells darken and the epithelial cell wall are lysed, preceding their disintegraton. In the epithelial cell organelles are scattered in the cytoplasm. Development of vcuoles are sparse at the early stage. Starch grains decreased gradually, while lipid droplets increased. Free ribosomes are distributed throughout the cytoplasm and secretory vesicles which originated from rough endoplasmic reticulum and Golgi complex are fused with the plasmalemma. These suggest that the cellular metabolism is active. Microtubules and plasmodesmata are typically observed in the thickened epithelial cell wall. Secretions are accumulated in duct lumen.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.195-201
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• 2018

This study was executed to evaluate the phenolic content, DPPH radical scavenging rate, and the cytotoxic effect in human cancer cell, 3T3-L1 cell from C. lanceolata extracts at various ethanol concentration. Total polyphenol and flavonoid content of the C. lanceolata at various ethanol concentration showed the high amount in 70%, 100% ethanol extract. The DPPH radical scavenging activity progressively increased in a dose-dependent manner, and showed the highest in 100% ethanol extract. The cytotoxic effect against human cancer cell of the C. lanceolata was higher in 50% and 70% ethanol extracts. In particular, the cytotoxic effect in MCF-7 cell was relatively higher than in other cells. The $IC_{50}$ (concentration causing 50% cell death) value showed the highest on MCF-7 cell ($538.39{\mu}g/m{\ell}$ in 70% ethanol extract, and exhibited significant activity against Hela cell ($637.87{\mu}g/m{\ell}$, Calu-6 cell ($728.64{\mu}g/m{\ell}$. The extract of 70% ethanol at $1,000{\mu}g/m{\ell}$ exhibited a pronounced cytotoxic effect on 3T3-L1 cell comparable to that of the other extracts, and reduced in a concentration-dependent manner.

• Journal of Plant Biotechnology
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• v.4 no.3
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• pp.123-127
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• 2002

Herbicide tolerant rice (Oryza sativa L. cv. Ilpumbyeo) cell lines were selected from $\gamma$-ray-irradiated anther-derived cell cultures. The anther-derived cell clusters were small (300 to 400 ${\mu}{\textrm}{m}$ in diameter) and uniform ones that were screened by miracloth filtering. The cell suspensions were very efficient to plate one layer onto agar medium and to screen target cell lines. Herbicide tolerant cell lines were selected by 5 mg/L cyhalofop butyl (CHB) treatment by using the small cell suspensions on agar N6 medium containing 1 mg/L 2,4-D and 0.2 mg/L kinetin. Of the cell lines, one line (CHB-1) showed stable tolerance at 10 mg/L concentration after 6-month culture without herbicide suspension. Growth stability of CHB-1 was similar to that of control cell line on 10 mg/L CHB containing medium. In this experiment we established herbicide tolerant cell line selection system by using anther-derived uniform-cell suspensions with $\gamma$-ray-irradiation.

• Journal of Plant Biology
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• v.29 no.3
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• pp.167-173
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• 1986

The effects of varying concentrations and durations of butachlor [N-(bytoxymethyl)-2-chlor-2', 6';-diethylacetanilide] treatment on oat (Avena sativa L.) root cell division were studied. Oats were treated from 0 to 48h with concentration ranging from 1$\times$10-6M to 1$\times$10-3M of butachlor. The highest concentration (1$\times$10-3M) of butachlor caused significant inhibition of cell division after 6h treatment. After 18h treatment, 49% and 66% inhibition of cell division occurred at 1$\times$10-5M and 1$\times$10-4M, respectively, while 16% inhibition of cell division occurred at 1$\times$10-6M concentration at same exposure period. Oat treated with 1$\times$10-5M and 1$\times$10-6M showed 69% and 38% inhibition of cell division after 36h. Increasing herbicide concentration at a specific time increased inhibition of cell division, and increasing the duration of treatment at a specific concentration also increased inhibition of cell division. In most instances the greatest inhibition of cell division occurred between 0 to 18h during 48h treatment. A range of concentration of 1$\times$10-5M to 1$\times$10-3M reduced cell enlargement significantly during 24h incubation period. The 1$\times$10-5M and 1$\times$10-3M caused 34% and 75% inhibition of cell enlargement. It was concluded that butachlor caused the growth inhibition of oats by inhibiting both cell division and cell enlargement.

• Journal of Plant Biology
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• v.32 no.4
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• pp.227-233
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• 1989

Single cells obtained from suspension culture of mature embryo-derived callus in wheat(Triticum aestivum L. cv Jang Kwang) were cultured to regenrated into the plantlet. Cell clusters and embryogenic calluses were efficiently developed from when the single cells clutured on the MS medium supplemented with 10${\mu}{\textrm}{m}$ 2,4-D. Upon transfer to hormone-free MS medium containing 10 mg/I AgNO3, embryogenic calluses gave rise to shoots, probably through somatic embryogenesis.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.881-882
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• 2005