• The Korean Journal of Zoology
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• v.33 no.4
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• pp.446-453
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• 1990

In order to investigate the retinoic acid indticed-differentiation of F9 teratocarcinoma stem cell, we have analyzed the change of cell morphology and laminin expression after exposure to retinoic add and cyclic AMP. It is shown that undifferentiated F9 stem cells grow as closely packed colonies, and it is difficult to distinguish cell-cell boundaries. After retinoic add and dibutyryl cyclic AMP treatment, F9 cells assume a flat morphology characterized by perinuclear granules and arrest growth. According to Northern blot analysis, laminin expression was increased markedly after retinoic acid treatment. Laminin Bi gene expression was increased at least 30-fold and laminin B2 gene expression was increased approximately 20-fold during differentiation process. Employing immunofluoresence analysis, it was proved that the synthesis of laminin protein was low level in F9 stem cell whereas it became high level in retinoic acid treated F9 cell and the laminin protein was largely accumulated in the cell surface. Our results suggest that induction of laminin Bi and B2 genes m F9 cells is retinoic acid-mediated control, and morphological change and differentiation of F9 cells might be associated with laminin gene expression.

• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.362-368
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• 1997

Five formae speciales of Fusarium oxysporum in Korea were examined using RFLP analysis to find the possibility for classification and analyze genetic variations. DNAs from F. oxysporum f. sp. lycopersici, cucumerinum, fragariae, garlic and sesami were used with three recombinant probes such as pFC46, pFC52 and pFC57. Distinct differences among five formae speciales of this fungus were detected in RFLP band patterns based on southern hybridization of genomic DNA using each recombinant clone, which was a repetitive copy probe. Strains belong to four formae speciales could be very stable in genetic variation except f. sp. sesami which has more variation than the others based on the RFLP analysis. They formed their own cluster which has high similarity within the same formae specialis resulted from the UPGMA analysis for genetic relationship analysis and each cluster represented its own formae specialis. The method using three recombinant DNA probes could be a good tool for classification of formae speciales in F. oxysporum.

• Journal of the Korean Geographical Society
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• v.39 no.3
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• pp.391-408
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• 2004

Modernism is understood as a process of differentiation. Postmodernism or postmodernity, by contrast, involves de-differentiation. There is a breakdown in the distinctiveness of each of spheres of social activities. It is important to explain an examination of the relationships between the de-differentiation and a wide variety of contemporary tourism, expecially postmodern tourism. Also, de-differentiation between the tourism and the social spheres lead to the spatial reflection. Aim of this paper is to examine the processes of de-differentiation between the tourism and the social spheres, which comes out spatially in Jeju island. Especially, location of destinations is concentrated on the coastline in the period of modem tourism. On the contrary, the postmodern tourism shows that the location of destinations are wide spread diffusion its vertically and horizontally. It means that there are to appear a breakdown of distinctiveness between the conventional tourism destinations and the regional person's space.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.69-76
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• 1994

Callus growth and shoot regeneration of Solanum and Lycopersicon depended on genotype, growth regulators, and thiamine concentration. L. peruvianum LA 1277 and L. peruvianum LA 1373 and PI 251301 had the greatest callus growth while L hirsutum LA 1777, L.esculentum 'Diego'and 'Red Plum' had the least callus growth. Lycopersicon penvianum genotypes were superior to L. esculentur genotypes in regenerating plants. MG medium was more effective in regenerating shoots than MS medium. A low level of IAA (0.2mg/L) and high level of BA (2 mg/L) resulted in the greatest shoot regeneration. Shoot growth varied depending on thiamine concentration and genotype. Shoot proliferation of Solanum ptycathum, Solanum nigrum, and L. peruvianum PI 199380 was best on medium with 20 mg/L thiamine. Regeneration of L. peruvianum PI 251301 and PI 128652 was better on medium with 30 and 10mg/L thiamine, respectively.

• Journal of Plant Biology
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• v.34 no.1
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• pp.25-30
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• 1991

This study was designed to investigate the relationships of cations to the polar regeneration of adventitious buds on midvein segments of poplar leaves. Basal regeneration was disturbed by adding $Ca^{2+}$. When higher concentration of exogeneous $Ca^{2+}$ was added to the WPM (Woody Plant Medium), the more adventitious buds were formed on midvein segments, and polar regeneration was inhibited. Added $Ca^{2+}$ from 0 to 9.70 mM with 0.5 mM of EGT A to WPM decreased the calcium effect. The treatment of $La^{3+$ with 7.05 mM of $Ca^{2+}$ ovecame the effect of $Ca^{2+}$. The cations $Mg^{2+}\;and\;K^{+}$ also caused regeneration on both basal and distal site. However, polar regeneration was maintained in the medium containing $Ca^{2+}$ without $Mg^{2+}$. The above result suggests that exogenous $Ca^{2+}$ or cations inhibit polar regeneration of poplar.poplar.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.143-148
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• 1995

The competence of callus formation and plant regeneration from root derived callus was higher in japonica cultivars than those of Tongil-type cultivars of rice. A japonica type cultivars Yeongdeogbyeo, showed the highest capacity (13%) for plant regeneration from root calli of 6 cultivars tested. The callus induced from seed and root tissues maintained higher capacity for plant regeneration during 7 passages of subculture on N$_{6}$ solid media at 2-week intervals. The maximum frequency (2 x 10$^{5}$ mL) of round cells and their cell colonies showed about 24 days after suspension culture of root-derived callus in N$_{6}$ medium with lmg/L 2,4-D, 300mg/L casein hydrolysate, 10mM L-proline, 20g/L sucrose and 30g/L sorbitol. The frequency of somatic embryo formation in suspension cultures of root-derived callus increased with prolonged advance of subculture time from 30 to 90 days, but their regenerative capacities decreased.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.77-82
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• 2000

This study was conducted to determine the inheritance of the ability of callus formation and plant regeneration in seed cultures of rice. The culturabilities of three Japonica rices,'Chucheongbyeo', 'Nagdongbyeo', and 'Daeribbyeo 1', were higher than those of Tongil type cultivars, 'Milyang 23' and 'Samgangbyeo 'The frequency for callus growth in F₂ populations of the three crosses, 'Milyang 23/Chucheongbyeo', 'Milyang 23/Daeribbyeo 1', and' Samgangbyeo/Nagdongbyeo', revealed a nearly normal distribution. The broad-sense heritability estimated from the ability of callus formation in the crosses were ranged from 83.8% to 90.1%. The frequency distribution of plant regenerability in F₂ population of 'Milyang 23/Daeribbyeo 1' showed a continuous variation. But the segregation mode of plant regenerability from seed-derived callus in the F₂ progenies of 'Milyang 23/Chucheongbyeo' and 'Samgangbyeo/Nagdongbyeo' appeared to fit the expected 3 : 1 ratio for the high and low regenerability. These results suggest that the high plant regenerability of 'Chucheongbyeo' and 'Nagdongbyeo' was regulated by a single dominant gene.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.145-150
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• 2001

Reactivation of human cytomegalovirus (HCMV) from latency is often fatal to immunocompromised individuals. To understand the effect of HCMV on human monocytes where HCMV establishes latency, two human monocyte cell lines at different stages in differentiation, THP-1 and HL-60 were infected with HCMV. While the viability and morphology of HL-60 cells were not significantly affected by HCMV, the viability of THP-1 cells was dramatically decreased by HCMV infection. THP-1 cells infected with HCMV became aggregated and adhered to the surface of culture dishes, probably due to the increased expression of adherence molecules CD11b on the infected THP-1 cells. THP-1 cells established a latent HCMV infection were induced to differentiate by treatment with TPA and hydrocortisone. Recovery of infectious HCMV from the culture supernatant of differentiated THP-1 cells was dependent on the time of induction of differentiation after HCMV infection. Thus, in vitro model of reactivation of HCMV from latently infected monocytes was established.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.765-767
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• 1999

Experiments were conducted to find out the optimum cultural conditions for adventitious shoot regeneration from leaf segments of Gypsophila paniculata L. Thidiazuron (TDZ) was remarkably effective for the regeneration of leaf segment in Gypsophila paniculata compared with BA and kinetin. TDZ showed the highest rate of regeneration at $3.0mg{\cdot}L^{-1}$, while kinetin did not affect the regeneration. BA in the medium increased vitrification. Shoot formation efficiency was much higher on $0.3mg{\cdot}L^{-1}$ of IAA-containing media than NAA-containing media. Regeneration of leaf segments was induced with the agar concentrations of 1.0, 1.2 and 1.6%. Dark treatment at the initial stage of the culture increased the rate of regeneration up to 75%. The leaf explants from the 3rd subcultured stock plants after meristem culture, showed the highest adventitious shoot regeneration efficiency.

• Journal of the Korean association of regional geographers
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• v.10 no.4
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• pp.833-850
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• 2004

Modernism is understood as a process of differentiation. Postmodernism or postmodernity, by contrast, involves de-differentiation. Recently, most museums have many social function, a central defining feature is its 'inscapes', or the spaces, architecture, material objects, texts, and meanings of exhibitions. Aims of this paper is to examine the processes and characteristics of differentiation and de-differentiation of the korean museums in historical development. The processes of differentiation and de-differentiation of the korean museums are divided into three phases: a establish stage of modem museum(l945$\sim$1974), a establish stage of postmodern museum(1975$\sim$1989), a diffusion stage of postmodern museum(1990$\sim$2003).