• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.285-290
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• 2009

A suitable system for plant regeneration has been established for perennial ryegrass (Lolium perenne L.). In order to investigate the effects of genetic variations of perennial ryegrass in tissue culture response, calli were induced from mature seeds of five cultivars, 'Topgun', 'Accent', 'Renenge GLX', 'Tetrellite', 'Bison' and plant regeneration frequency was compared. Significant differences were observed among the cultivars in both callus induction and plant regeneration. Genotype 'Accent' consistently performed best in the callus formation and plant regeneration. These results can be used useful for molecular breeding of perennial ryegrass through genetic transformation.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.571-584
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• 1991

잉어과(Gyprinidae)의 Zocco속 어류 4종과 Candidia속 어류 1종에 대한 종간 유연관계와 종분화 연대측정 및 이들의 지질학적 분포경로를 밝히기 위하여 한국, 일본 및 대만에서 채집된 개체를 대상으로 전기영동법에 의한 유전자 분석을 하였다. 각 종의 지역별(한국, 일본, 대만) 집단간 유전적 유연관계를 분석한 결과 평균 유전적 근연치는 90% 이상이었다. Z. temmincki의 경우 일본집 단들은 한국의 A-type 집단과는 유연관계가 가까왔으나 한국의 B-type과는 유전적 차이가 현저하러다. Z. PlaD여5의 경우 한국집단과 일본집단사이의 유연관계는 S = 0.852였고, 한국집단과 대만집단 사이는 5 = 0.672, 일본집단과 대만집단 사이는 S = 0.751로서 지리적으로 현저한 차이를 업였다. Z. pochycephalus 3개 집단간의 유전적 근인치는 S = 0.963이었고 Candidia borbota 2개 집단간은 S = 0.946이었다. 종간의 유전적 근연환계를 비교한 결과 Candidia borbota와 Z. temmincki사이는 S = 0.608, Z. pluDpus와 1. pachycephalus사이는 S = 0.612였으나, Z. temmincki와 Z. platypus사이는 S = 0.441, Z. temmincki 와 Z. pochycepholus 사이는 S = 0.350이었고, Z. plotpus와 Condfda barbata사이는 S = 0.328로서 이들 사이에는 현저한 유전적 차이가 있었다. 각 종간의 롱분화 연대를 추산한 결과 이들은 약 480만년 전인 Pliocene 초기에 공통 조상종에서 분화하여 Z. temmincki, Candidia borbato group과 Z. plotypus, Z. pochycepholus group으로 분리되었고 약 260만년 전인 Pliocene 후기에 Z. temminc소와 Candidia borbota로 분화되었다고 추산되며 약 80만년 전인 Pleistocene시기에 남 temmincki B-type에서 h-type이 분화되었다짙 여겨진다. 한편 또 다른 한 단opP은 약 230만년 전인 열iocene후기에 대만 지역의 Z. plotypas에서 Z. pochvcepholus가 분화된 후 현재에 이르렀다고 추정된다. Z. platypus는 약150만년 이전인 초기 Pleistocene시기에 대만지역에서 한국 및 일본집단으로 분리되었다고 보며 이들 한국집단과 일본집단은 약 50만년 전 Pleistocene의 Middle기에 고황하 수계를 거쳐 현재의 분포 상황에 이르렀다고 여겨진다. 한편 대. temmin체과의 B-type에서 저온 적응으로 분화되었다고 추측되는 A-type은 약 20만년 전인 Pleistocene의 Riss기에 역시 고황하 수계를 통하여 한국과 일본으로 분포하여 현재에 이르렀다고 사료된다.

• Journal of Life Science
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• v.22 no.4
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• pp.447-455
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• 2012

Akt plays an important role in a variety of cellular physiologies such as growth, proliferation, and differentiation. In skeletal muscle, Akt has been implicated in regulating regeneration, hypertrophy, and atrophy. In this study, the role of Akt has been examined during skeletal muscle differentiation. Culturing C2C12 myoblasts under low serum (1% horse serum) and high density converted cell morphology from a round shape to an elongated and multi-nucleated shape. Morphological changes were initiated from day 2 of differentiation. In addition, the expression of both myogenin G and myogenin D was elevated from day 2 of differentiation. Skeletal muscle differentiation was abolished by silencing Akt1 or Akt2, but was significantly enhanced by the over-expression of either Akt1 or Akt2. The activation of Akt was observed from day 2 of differentiation and disappeared after day 7. The expression of kruppel-like factor 4 was observed from day 6 of differentiation. Moreover, this expression was blocked in cells silencing either Akt1 or Akt2. In addition, the promoter activity of kruppel-like factor 4 was significantly reduced in cells silencing Akt1 or Akt2. These results suggest that Akt regulates skeletal muscle differentiation through the regulation of kruppel-like factor 4 expression.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.43-48
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• 1997

Apical meristems of Wasabia japonica were cultured on Murashige and Skoog's medium supplemented with cytokinins alone or together with 1.0 mg/L IAA. Shoot initials could be induced from leaf primordia on apical meristems. Calli and roots were formed on the medium containing cytokinins and 1.0 mg/L IAA in combination after 30 days of culture, but there were no callus proliferation. Shoot organogenesis began after 60 days of culture and these small shoots elongated when transferred to a medium containing 1.0 mg/L BA or kinetin. Shoots were formed directly without callus induction from apical meristems all the explants on the medium containing cytokinins variously, and most of the shoots proliferated multiple shoots which could be divided to obtain plantlets. Shoot multiplication rate in response to cytokinins was best on the medium containing 1.0 mg/L BA or 2.0 mg/L zeatin. Divided plantlets rooted well on MS medium containing 0.01 mg/L IBA after 15~30 days of subculture and the rooted plantlets developed into whole plants with multiple shoots. After rooting, the regenerated plants were washed and transferred to the pots containing sterilized soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.486-491
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• 2002

Spikelet number and its components of rice plant are closely associated with nitrogen accumulation and biomass production during panicle formation stage. To elucidate this relationship and also compare the differences of the sink formation efficiency among cultivars, spikelet number, its components, nitrogen content, nonstructural carbohydrate content, and plant dry matter were investigated under 5 nitrogen levels with two split application methods and shading treatments by using three rice varieties. The nitrogen amount in shoot at panicle initiation stage and at 15 days after panicle initiation showed significant positive correlation with primary rachis branches per square meter, and that at 15 days after panicle initiation and at heading stage with secondary rachis branches per square meter, Primary and secondary rachis branches per square meter showed positive significant correlation with the shoot dry weight at panicle initiation stage and at 15 days after panicle initiation stage, respectively, The amount of degenerated secondary rachis branches and spikelets per square meter showed significant negative correlation with the dry weight and nonstructural carbohydrate increase of stem during 15days after panicle initiation, and the contents of nonstructural carbohydrate at 15 days after panicle initiation. Spikelets per unit area showed significant positive correlation with nitrogen amount in shoot and shoot dry weight at heading stage. The sink formation efficiency expressed as the spikelet number produced by the unit amount of nitrogen in shoot at heading stage was higher in Nampoongbyeo than Choocheongbyeo and Hwaseongbyeo. Sink formation efficiency was negatively correlated with the dry weight increase of shoot and stem during reproductive stage. but not significantly with that of leaf in all varieties. Sink formation efficiency was not significantly correlated with nonstructural carbohydrate, but was significantly negatively correlated with structural carbohydrate increase during reproductive stage.

• Development and Reproduction
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• v.12 no.3
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• pp.267-274
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• 2008

Differentiation of blastocyst is critical step for implantation and is under the control of regulation factors originated from embryo or reproductive tracts. The sequential communication with those factors is suspected as critical events for differentiation. It has been suggested that intracellular signaling pathways activated by calcium is essential in differentiation of blastocyst. Previously, it was known that concanavalin A (Con A) increase the levels of free calcium in blastocyst stage. However, Con A can not accelerate the hatching, although heparin-binding epidermal growth factor-like growth factor (HB-EGF), a modulator of calcium level, accelerate the hatching of blastocyst. In this study, it was investigated whether Con A or prostaglandin $E_2$ ($PGE_2$) can modulate the differentiation of blastocyst. Con A accelerated the expansion of blastocyst in both 1 hr pulse treatment group and continuous treatment group. However, Con A significantly suppressed the hatching in both groups. The inhibition was significantly strong in continuous treatment group compared with 1 hr pulse treatment group. On the other hand, $PGE_2$ induced the increase the free calcium level, but did not accelerate the expansion. In addition $10{\mu}m\;PGE_2$ inhibited hatching. However, $PGE_2$ could accelerate hatching in Con A pretreated blastocyst. $PGE_2$ also caused the increase of free calcium level in Con A pretreated blastocyst. From these results, it is suggested that changes of the free calcium level induce a different calcium-mediated signaling pathways. In addition, sequential stimulation by signal molecules may triggers the cellular mechanisms for the differentiation of blastocyst.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.233-237
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• 1994

Plant regeneration system via somatic embryogenesis in leaf explant cultures of Gentiana scabra var. buergeri has been established. Leaf segments formed calli when cultured on MS medium supplemented with 0.5 mg/L 2,4-D and 2 mg/L BAP After transferred to SH medium supplemented with 0.5 mg/L 2,4-D, 2 mg/L CPA and 0.5 mg/L kinetin, the callus became embryogenic. The embryogenic callus was subcultured every 3 to 4 weeks. Upon transfer onto SH basal medium the embryogenic callus gave rise to numerous somatic embryos, which subsequently developed into plantlets. The regenerated plants were potted in an artificial soil with mixture (peatmoss : pearlite : vermiculite : 2 : 1 : 1) and transplanted to the soil after kept under a high humidity for two weeks. A total of 78 plants out of 105 regenerated plants survived in the soil. Phenotypic variations in height, number of stems and the flowering time were observed in tile regenerated plants. Cytogenetical analyses showed no chromosomal variation.

• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.177-182
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• 2003

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.303-314
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• 2014

Mt. SAKRAJIMA in southern Kagosima, japan is one of the most active volcanoes in the world. On 18 August 2013, the SAKRAJIMA volcano recently went into the largest scaled eruption with a huge plume of volcanic ash. Therefore, the concern arises if this considerable amount of ashes might flow into the Korea peninsula as well as Japan. In this paper, we performed numeric experiment to analyze how volcanic product resulted from the SAKRAJIMA volcano has impacted on Korea. In order to predict the spread pathway of ash, HYSPLIT model and UM data has been used and 17th September 2013 has been selected as observation date since it is expected that the volcanic ash would flow into the South Korea. In addition, we have detected ash dispersion by using optical Communication, Ocean and Meteorological Satellite- Geostationary Ocean Color Imager (COMS-GOCI) images. As the results, we come to a very satisfactory conclusion that the spread pathway of volcanoes based on HYSPLIT model are matched 63.52 % with ash dispersion area detected from GOCI satellites image.

• Korean Journal of School Psychology
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• v.17 no.1
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• pp.65-86
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• 2020

The purpose of this study was to examine whether self-differentiation mediates the relationship between adolescents' family functioning and self-esteem and to examine whether peer support and family conflicts had moderated mediating effects. For this purpose, 522 students from four high schools in Gyeonggi province were surveyed about their family functioning, self-differentiation, self-esteem, and peer support. The results were analyzed using SPSS 21.0 and PROCESS. The mediating, modulating, and moderated mediating effects were analyzed. The results of this study were as follows. First, correlation analysis showed that family functioning, self-differentiation, self-esteem, and peer support were significantly positively correlated. Second, the moderated mediating effects of peer support were as follows. First, self-differentiation had a partial mediating effect in the relationship between family functioning and self-esteem such that family functioning and self-differentiation were positively correlated and self-differentiation and self-esteem were positively correlated. Second, peer support had a moderating effect in the relationship between family functioning and self-differentiation that promoted self-differentiation. Thus, peer support affected family functioning and self-differentiation. Third, verifying the moderated mediating model of peer support by combining the mediation model of self-differentiation and the moderation model of peer support identified above showed that self-differentiation mediated the relationship between family functioning and self-esteem. Thus, family support affected self-differentiation and self-differentiation affected self-esteem. The significance of this study was as follows. First, it showed that self-differentiation significantly mediated the relationship between family functioning and self-esteem, clarifying the relationship between family functioning and self-esteem. Second, it showed that peer support moderated the relationship between family functioning and self-differentiation, identifying a mechanism that promotes self-differentiation. Third, it showed the mediation of self-differentiation of the relationship between family functioning and self-esteem depended on peer support.