• Journal of Ginseng Research
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• v.14 no.2
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• pp.107-111
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• 1990

Ginseng root explants and calli were cultured on modified Murashine and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical compositon and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of ginseng calli, the concentrations of 2, 4-D and sucrose were in the range of 1 to 5 mg/l and 1 to 3%, respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magnesium, plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng.

• Journal of Plant Biotechnology
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• v.3 no.3
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• pp.141-144
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• 2001

To enhance the shoot induction efficiency from nodal stem of yooza, the culture conditions such as basal medium, carbohydrate source, solidifying agent and the optimum concentration of plant growth regulators for shoot induction were investigated. The nodal explants were cultured better on MS medium than on MT, SH, B5 or W media in considering of shoot induction rate and mean shoot length. Solidifying agent in medium was better with 0.8% agar than with 0.3% agar, 1.2% agarose or 0.2% gelrite. Carbohydrate source in shoot induction medium was efficient with 30 g/L sucrose. The optimum concentrations of plant growth regulators were determined that 0.1 mg/L NAA as auxin was effective on the shoot induction, and 1.0 mg/L BAP as cytokinin induced multiple shoots efficiently. Shoot induction was the most effective on MS medium supplemented with 4 mg/L $GA_3$ in yooza.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.6-9
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• 2005

Plant biotechnology involving genetic modification has been rather controversial. However, the major issues related to safety are being addressed by continued improvements in technology. Some of the related facts will be highlighted to set the tone for a scientific discussion on the possibilities of using the technology for crop improvement. Our main research interest is to understand the molecular regulation of shoot bud regeneration in plant tissue culture, which is essential for crop improvement by biotechnology. We have isolated and characterized some genes that are associated with adventitious shoot regeneration. These include a MADS-box cDNA (PkMADS1) from paulownia kawakamii, which regulates vegetative shoot development and in vitro shoot regeneration from leaf explants. Another gene we have characterized from petunia codesfor a cytokinin binding protein (PETCBP). Preliminary functional analysis of this gene indicated that this also affects adventitious shoot bud initiation. Also, the antisense suppression of this gene in petunia causedexcessive branching. Results from our work and selected other publications will be used to highlight the possibilities of manipulation of such genes to improve crop species.

• Journal of Plant Biology
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• v.11 no.3
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• pp.23-30
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• 1968

Using several varieties of Cymbidium, investigations were carried out to make clear how the protocormic tissue develops from the cultured explant. Explant to be cultured were prepared in several ways: exclusively apical meristem, apical meristem dissected out with the basal part attached, axillary bud primordia in their initial stage of development, or apical or axillary bud dissected out as a whole etc. It was observed that protocorms or protocormic tissues were developed from the explant's meristematic tissues regardless of where these tissues were located. Apical meristem, leaf primordia, leaf axil, or internodal part of young bud turned easily protocormic, while the scaly leaves of axillary bud or stem tissue of mother shoot turned quickly brwonish and died away. Both in axillary and apical bud explant alike, whether they were cultured whole or divided, some took quickly green color while others were slower, and some developed protocorms easily while others remained unchanged for months. Varietal difference as well as environmental factors seemed to be responsible for it. Further details should be clarified by histogenetical investigations.

• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.387-393
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• 2000

The process by which Agrobacterium tumefaciens genetically transforms plants involves a complex series of reactions communicated between the pathogen and the plants. To identify plant factors involved in agrobacterium-mediated plant transformation, a large number of T-DNA inserted Arabidopsis thaliana mutant lines were investigated for susceptibility to Agrobacterium infection by using an in vitro root inoculation assay. Based on the phenotype of tumorigenesis, twelve T-DNA inserted Arabidopsis mutants(rat) that were resistant to Agrobacterium transformation were found. Three mutants, rat1, rat3, and rat4 were characterized in detail. They showed low transient GUS activity and very low stable transformation efficiency compared to the wild-type plant. The resistance phenotype of rat1 and rats resulted from decreased attachment of Agrobacterium tumefaciens to inoculated root explants. They may be deficient in plant actors that are necessary for bacterial attachment to plant cells. The disrupted genes in rat1, rat3, and rat4 mutants were coding a arabinogalactan protein, a likely cell wall protein and a cellulose synthase-like protein, respectively.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.23-23
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• 2002

We established hairy root cultures of F. esculentum transformed with A. rhizogenes for in vitro rutin production. Additionally, we describe the effects of different media and plant growth regulators on growth and rutin biosynthesis in buckwheat hairy root cultures. Excised leaves of P. tinctorium from 10-day-old seedlings were used as the explant material for co-cultivation with A. rhizogenes 15834. The hairy culture of Fagopyrum esculentum Moench. was established by infecting leaf explants with Agrobacterium rhizogenes 15834. About four to five weeks after co-cultivation with A. rhizogenes, 10 hairy roots were excised from the necrotic explant tissues. After repeated transfer to fresh medium for three months, ten clones were transferred to MS liquid culture medium. The growth and rutin production of each clone differently response to the MS liquid medium. Among these clones, H8, which had exhibited good growth rate and one of the highest rutin productivity, was selected for the following experimment.(중략)

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.415-418
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• 2004

The effects of sonication and vacuum infiltration on transformation efficiency was investigated by using immature embryos of Korean wheat as explants. Two Agrobacterium tumefaciens strains, KYRT1 and EHA105, carrying pCAMBIA 1305.1 were used. Transformation efficiency was demonstrated by the detection of $\beta-glucu-ronidase$ (GUS) activity. GUS expression showed clear difference among Korean wheat cultivars. Geurumil showed higher GUS expression efficiency $79.1\%$ compared with other cultivars. The effects of the duration of vacuum infiltration and sonication treatment showed a tendency high GUS expression efficiency by their combination. In comparison with other Agrobacterium strains, KYRT1 showed high efficiency in most Korean cultivars.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.173-176
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• 1994

Stem and petiol explants of peony culture turned to brownish black soon after placing onto medium and degenerated to death. Disroloration was caused mainly by ferrous and calcium cloride. Nitrate was a main factor for the death of culture. The culture damage was increased with the increment of the medium salt strength. A few latent axillary buds were elongated to shoots without forming callus.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.177-182
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• 1994

Cotyledon segments of korean ginseng produced somatic embryos when cultured on MS basal medium, whereas plumule or excised axis explants did not. histological examination revealed that the cells in proximal region of cotyledon turned meristematic and densely cytoplasmic was composed of smaller and more densely cytiplasmic cells than the subepidermal cells. however, in the case both epidermis and subepidermal cells were almost the same in size and cytoplasmic density, the embryo originated from multiple cells.

• BMB Reports
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• v.53 no.7
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• pp.367-372
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• 2020

Cell cycle-related kinase (CCRK) has a conserved role in ciliogenesis, and Ccrk defects in mice lead to developmental defects, including exencephaly, preaxial polydactyly, skeletal abnormalities, retinal degeneration, and polycystic kidney. Here, we found that Ccrk is highly expressed in mouse trachea and bronchioles. Ccrk mutants exhibited pulmonary hypoplasia and abnormal branching morphogenesis in respiratory organ development. Furthermore, we demonstrated that Ccrk mutant lungs exhibit not only impaired branching morphogenesis but also a significant sacculation deficiency in alveoli associated with reduced epithelial progenitor cell proliferation. In pseudoglandular stages, Ccrk mutant lungs showed a downregulation of Hedgehog (Hh) signaling and defects in cilia morphology and frequency during progenitor-cell proliferation. Interestingly, we observed that activation of the Hh signaling pathway by small-molecule smoothened agonist (SAG) partially rescued bud morphology during branch bifurcation in explants from Ccrk mutant lungs. Therefore, CCRK properly regulates respiratory airway architecture in part through Hh-signal transduction and ciliogenesis.