• The Plant Pathology Journal
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• v.40 no.2
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• pp.160-170
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• 2024

Erwinia amylovora is a plant pathogen that causes fire blight on apples and pears. Bacteriophages, which are viruses that selectively infect specific species of bacteria and are harmless to animal cells, have been considered as biological control agents for the prevention of bacterial pathogens. In this study, we aimed to use bacteriophages that infect E. amylovora as biocontrol agents against fire blight. We isolated bacteriophages Fifi044 and Fifi318 infecting E. amylovora, and characterized their morphology, plaque form, and genetic diversity to use as cocktails for disease control. The stabilities of the two phages were investigated at various temperatures and pH values and under sunlight, and long-term storage experiment was conducted for a year. To evaluate whether the two phages were suitable for use in cocktail form, growth curves of E. amylovora were prepared after treating the bacterial cells with single phages and a phage cocktail. In addition, a disease control test was conducted using immature apples and in vitro cultured apple plantlets to determine the biocontrol effects of the phage cocktail. The two phages were morphologically and genetically different, and highly stable up to 50℃ and pH value from 4 to 10. The phages showed synergistic effect when used as a cocktail in the inhibition of host bacterial growth and the disease control. This study demonstrated that the potential of the phage cocktail as a biocontrol agent for commercial use.

• Korean Journal of Pharmacognosy
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• v.35 no.2 s.137
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• pp.164-170
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• 2004

The flavonoids are a very large and important group of polyphenolic natural products, which are united by their derivatization from the heterocycle, flavone. They are distributed in higher plants and occur widely in the fruits and vegetables that make up the human diet. They exhibit a wide range of biological properties, including antitumor, antiinflammatory, hepatoprotective, antimicrobial, insecticidal and estrogenic activities. They are also major components of many plant drugs and it is possible that they contribute to the curative properties. For the purpose of developing anticancer agent of natural origin, we have evaluated forty four kinds of naturally occurring flavonoids for the inhibitory activity upon the proliferation of cultured human tumor cells such as A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon) in vitro.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.196-201
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• 1997

To characterize active cells during microspore culture of Angelica gigas, flow cytometric and epifluorescent techniques were applied. The knowledge obtained from these types of studies will give us insight into early stage in plant development and may lead to the application of microspore-derived from haploid plants for breeding in recalcitrant species. Viability of cultured microspore differed depending on the developmental stages. Frequencies of active cells from tetrad, uni-nucleate, bi-nucleate and matured pollen were 12.8, 49.3, 42.3 and 31.7%, respectively. Alive microspores have luminescent the green fluorescence stained with FDA and blue fluorescence stained with DAPI.

• Korean Journal of Medicinal Crop Science
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• v.10 no.3
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• pp.217-221
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• 2002

Callus induction and embryogenesis were studied in three different genotypes of Acanthopanax senticosus, to develop a protocol for somatic embryogenesis and acclimatization. Young leaf, stem, node, petiole, peduncle, flower and root explants were collected from 3-year old trees of A. senticosus accessions (Korea, Russia and Japan). Callus was obtained from all cultured explants but showed the higher rate of callus formation in flower cultured. For the three A. senticosus accessions, callus was well formd on MS media containing 2mg/ l of 2,4-D and 2mg/ l of TDZ, 4mg/ l of 2,4-D and 1mg/ l of TDZ than other treatments. For three A. senticosus accessions, when callus transferred to MS medium with 2,4-D, embryogenic cell formed. For A. senticosus accessions Korea, embryogenic cells were obtained on callus induced from petiole, stem, node and root explants, and induction rate was lower than 3%. 200mg of embryogenic callus was transferred to MS free liquid medium and somatic embryos of heart stage were obtained after 45days of culture. When somatic embryo of germination stage were transferred to solid medium, most of the embryos were regenerated into plantlets on 1/4 MS medium. Normal plants with both shoots and roots were transferred to greenhouse soil and were successfully acclimatized.

• Korean Journal of Plant Resources
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• v.6 no.1
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• pp.25-32
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• 1993

Many plants, which collected from Korea, were applied to antitumor and cytotoxic screeing tests against sarcom 180 a ascitec in mice, V-79 KB and P388 cultured cells. The results are summarixed as follows:1) The total packed cell volum method has been used for the antineoplastic screening for from natural higher plants in Korea. By this method, we have found out that the root, leaf and stem of Tripterygiu, regelii Spragne & Taketa having strong antineoplastic activity and also Rumex Japonicus Houtt. Eragrositis ferru-ginea Beauv. and Patrinia scabio-saefolia Fischer showed significant activity to anticancer tumor while cynanchum wilfordii Hemsley, and Rosa polyantha Sieb. et Zacc. showed slight activity to antitumor. 2) Among the 13 tested plants, the root and stem of Tripterygium regelii Spragne & Taketa and Amethystanthus excisus Nakai showed strong antitumor activity by the V79 cytotoxic cell screening test. 3) Twelve plants, which are glowing in mountainous area of Korea tested to anticancer activity. From the results, Eragrositis ferru-ginea Beauv., Angelica gigas Nakai, Geranium sibiricum L., Patrinia scabio-saefolia Fisher, Cynanchum wilfordii Hemsley, and Rubia akane Nakai have been proved to be anti-cancer plants by using P388 cell cultured method. 4) Tripterygiu, resgelii Spragne & Taketa, Eragrositis ferru-ginea Beauv., Patrinia scabio-saefoli Fisher, Cynanchum wilfordii Hemsley and Rasa polyantha Sieb. et Zacc., var. genuina Thunb. showed strong anti-tumor activity both total packed cell volume method and Cytotoxicity method.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.127-132
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• 2004

A suitable bioreactor culture system for shoot proliferation and bulblet formation of Allium victorialis var. platyphyllum Makino was established. Uptake of soluble carbohydrates in different bioreactor culture systems was also analyzed during the entire culture period. Optimal conditions for multiple shoot formation were determined in raft culture (RC) and modified raft culture system (MRC) (13-15 per explant) in which the explants were placed on a net contacting liquid medium. For bulblet formation and enlargement, 93.4％ of shoot clumps formed bulblets at the basal part. Furthermore, they were uniform in size when cultured with ebb & flood system (E&FS). Bulblets harvested from RC and MRC showed vigorous rooting, however, their growth was not uniform. Whereas soluble carbohydrate contents in the bulblets cultured in E&FS were low, starch content was high. Sucrose, glucose and fructose concentrations in the medium of E&FS culture system decreased as bulblet formation and enlargement proceeded, suggesting that external sucrose is taken up to by the cells before it is hydrolyzed.

• Korean Journal of Plant Resources
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• v.24 no.6
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• pp.712-718
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• 2011

Ginseng (Panax ginseng) is frequently used in Asian countries as a traditional medicine. The major components of ginseng are ginsenosides. Among these, ginsenoside compound K has been reported to prevent the formation of malignancy and metastasis of cancer by blocking the formation of tumor and suppressing the invasion of cancer cells. In this study, ginsenoside $Rb_1$ was converted into compound K, via secreted ${\beta}$-glucosidase enzyme from the Leuconostoc lactis DC201 isolated, which was extracted from Kimchi. The strain DC201 was suspended and cultured in MRS broth at $37^{\circ}C$. Subsequently, the residue from the cultured broth supernatant was precipitated with EtOH and then dissolved in 20 mM sodium phosphate buffer (pH 6.0) to obtain an enzyme liquid. Meanwhile, the crude enzyme solution was mixed with ginsenoside $Rb_1$ at a ratio of 1:4 (v/v).The reaction was carried out at $30^{\circ}C$ and 190 rpm for 72 hours, and then analyzed by TLC and HPLC. The result showed that ginsenoside Rb1 was transformed into compound K after 72 hours post reaction.

• Korean Journal of Plant Tissue Culture
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• v.27 no.3
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• pp.175-180
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• 2000

Cotyledonary somatic embryos after being cultured in a liquid MS medium for 1 week were subcultured on a solid MS medium and then the embryos germinated at a rate of 92%, but the rate was lowered by extending the culture period of the embryos on a liquid medium: 26% germination on a liquid medium culture for 4 weeks. Somatic embryos subcultured on the liquid medium showed the normal elongation of hypocotyl and radicle but in part showed secondary embryogenesis on hypocotyl and callus formation on and around the root-hypocotyl juncture. Through observation of scanning electron microscope, apical meristem in plumule showed the loose arrangement of cells, and abnormal leaf primordium formation and growth arrest of the primordium or no leaf primordium formation. Therefore, it is suggested that the germination arrest of carrot somatic embryos on liquid medium culture is due to the structural abnormality of the apical meristem in plumule.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.147-154
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• 1982

This study was conducted to investigate an effective method of protoplast isolation, the plating efficiency for cell division, and fusion of plant protoplasts by polyethylene glycol for somatic hybridzation. The effectiveness of protoplast isolation was different with the various enzyme concentrations, but, in the protoplast isolation from tobacco mesophyll, the enzyme solution with 0.5% macerozyme and 2.0% cellulase was very effective. The protoplast isolation from callus cultured in vitro for a long period was not obtained in any of the enzyme solution used. Protoplasts divided actively at cell densities above $10^44/ml and at $25^{\circ}C$ under 12hr illumination by inflorecient light (l50 Lux), regardless of presence of agar. The highest frequency of protoplast fusion was obtained after treatment with a solution of 0.33 M polyethylene glycol 1500.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.129-135
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• 1997

Morphogenetic responses were investigated by culturing embryo and leaf explants of Korean wild type tea plant, Camellia sinensis (L.) O. Kuntze. Induction of direct somatic embryogenesis as well as adventitious and/or axillary shoots was obtained from mature zygotic embryo cultures on Murashige and Skoog (MS) basal medium having 5 to $20\mu\textrm{M}$cytokinin a lone. Morphogenetic response was decreased dramatically by the addition of auxins tested. One hundred percent of induced and isolated shoots formed roots after four weeks of culture on half-strength MS or quarter-strength Schenk and Hildebrandt (SH) media supplemented with $10\mu\textrm{M}$indole-3-butyric acid (IBA). Immature zygotic embryos were shown to be a suitable explant for embryogenic callus formation in the presence of 2, 4-dichlorophenoxyacetic acid(2, 4-D) in basal medium. Mature zygotic embryo originated leaves were used to test their ability for mophogenesis by incorporating plant growth regulators such as IBA, naphthyl-1-acetic acid (NAA), and 6-benzylaminopurine (BAP). Apparently, the morphogenetic responses of the cultured explant sources on the types and/or levels of plant growth regulators tested were observed visually.