• Journal of the Geological Society of Korea
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• v.54 no.5
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• pp.513-527
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• 2018

We have carried out granulometry and component analysis on pyroclastic deposits of the Maljandeung Tuff, Ulleung Island, to interpret the eruption types and prime dynamic mechanisms. It is divided into three members in the extracaldera area, each of which comprises the lithofacies of coarse tuffs and lapillistones in the lower part, and pumice deposits in upper one. The lithofacies present quantitative evidences in the granularity and component distribution patterns. As compared to the pumice deposits, the coarse tuffs and lapillistones exhibit a relative increase in both the lithic/juvenile and the crystal/juvenile ratios, and a preferential fragmentation of the juvenile fraction. The abundance of lithics and crystals in the tuffs and lapillistones can be attributed to preferential fragmentation of the aquifer-hosting rocks due to explosive evaporation of ground water, and indirect enrichment in lithics and crystals due to removal of juvenile fines from eruptive cloud. The above data exhibit that early phreatopmagmatic phase was followed by purely magmatic fragmentation phases. The coarse tuffs and lapillistones suggest phreatoplinian eruption derived from explosive interaction of magma with ground water near the conduit, while pumice deposits indicate magmatic eruption by magmatic explosion from juvenile gas pressure. In early stage, phreatoplinian eruption occurred from explosive magma/water interaction in connecting confining water with drawdown of the magma column in the conduit; Later it shifted to plinian eruption by explosive expansion of only magmatic volatiles in intercepting water influx due to higher magmatic gas pressure than confining water pressure with rising of the magma column in the conduit.

• Economic and Environmental Geology
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• v.34 no.6
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• pp.617-625
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• 2001

The Skaergaard intrusion is widely considered a type example of a strongly fractionated, layered intrusion that has undergone extensive in situ igneous differentiation. The Intrusion, therefore, should be a good locality for modeling trace element vriation in a closed system. Previous studios (Haskin and Haskin, 1968; Faster et al., 1974), however, have suggested thats the rare earth elements in whole rocks and mineeral separates from the Intrusion did not fellow the expected trend for closed system crystatllization. Trace element modeling using published distribution coefficients, modal abundances of the coexisting minerals, and the concentration of trace elements In whole rocks and mineral separates from the Skaergaard Intrusion, reveals that the rare earth elements were significantly Influenced by the crystallization of abundant apatite in the Layered Series suring the final stages of crystallization. The results of trace element modeling also suggcsts that apatite, which appears sporadically in the UBS, is not a primary liquidus phase in these samples as previously suggested (Naslund, 1984) but an interstitial phase that (lid not directly effect trace element abundances In the evolving magma As the Skaergaard magma coaled convection, or convected as small Isolated cells during the final stages of differentiation, an elebated $P_{H2O}$ Induced by accumulation of volatile elements near the roof of the magma chamber ingibited or delayed the precipitation of primary apatite in the UBS If the Skaergaard differentiation Is modeler assuming primary apatite crystallization In the upper par of the LS where abundant modal apatite is present, and only late stage crystallization of apatite In the UBS where apatite Is less abundant, rare earth elements abundances follow a closed system variation trend. These results rule but any differentiation model for the Skaergaard Intrusion that Includesvolumetrically significant injections or discharges of magma Into or out of the chamber during the final 20% of the crystallization history.

• Journal of Plant Biology
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• v.35 no.1
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• pp.17-23
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• 1992

Effects of polyamines and their biosynthetic inhibitors on adventitions shoot regeneration of Populus leaf segments were investigated. Polyamine inhibitors such as difluoromethyl arginine (DFMA), difluoromethyl ornithine (DFMO), and dicyclohexylamine (DCHA) decreased the fresh weight of cultured leaf segment and the rate of adventitious shoot regeneration. The inhibitory effects of DCHA were stronger than any other oplyamine inhibitors, and the rest were in the order of DFMO and DFMA. The inhibitory effects of these inhibitors were lessened or disappeared by the addition of polyamines, among which spermidine was the highest in its effect. Therefore, it is suggested that the spermidine may be related to the adventitious shoot regeneration of Populus leaf segments.gments.

• Korean Deer Journal
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• v.7 no.10 s.48
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• pp.60-64
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• 2002

알려진 녹용의 효능을 과학적으로 증명하고 활성성분을 이용하여 신의약품 개발에 기여하고자 한다. 본 연구실에서는 녹용의 가장 대표적인 효능인 조혈작용을 하는 성분을 구조 분석하여 MADG임을 밝히었다. MADG는 조혈촉진기능뿐만 아니라 대식세포 증식기능 그리고 비장세포성장을 촉진하는 등 면역활성 조절제로써의 기능도 나타내었다. 그리고 녹용에 존재하는 인지질 중에서 포화지방산을 가지고 있는 phophatidylcholine도 면역활성을 촉진시키었다. 항진균작용을 하는 성분을 구조 분석한 결과 lysophophatidylcholine임을 밝히었으며 그 유도체인 CHJ-ester가 숙주세포에는 해를 주지 않으면서 항진균작용을 하는 것을 관찰하였다. 그리고 골다공증치료효과를 검색하기 위해 녹용 정제성분으로 연구한 결과 파골세포로의 분화를 100$\%$ 저해함을 밝히므로 녹용이 골다공증 치료효과가 있음을 증면하였다. 녹용성분의 유도체인 SCOH가 파골세포분화를 억제함을 밝혀 현재 골다공증치료제로써의 가능성을 조사하고 있다. 본 연구실에서는 1999년부터 녹용연구를 시작하여 현재까지 10여 개의 활성성분을 분석한 바 있다. 현재 조혈세포촉진작용, 면역증진작용, 골다공증치료작용, 대식세포 증식작용, 항진균작용, 항간질작용에 대한 성분 분석 및 그 약리 기전을 연구하고 있다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.50-50
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• 1993

최근의 암치료용 제제는 암세포의 분화를 재개시켜서 정상적인 세포로 분화 유도하는 약재개발에 촛점을 맞추고 있으므로 본 연구에서는 F9 EC세포주에 의한 분화인자 스크리닝 시스템을 확립하고 나아가 새로운 분화 유도인자를 스크리닝 하는데 그 목표를 두고 연구를 수행하였다. 즉 F9 EC세포의 세포 배양조건을 먼저 확립하였으며 retinoic acid에 의한 F9 EC세포의 분화유도 시스템을 다음과 같이 확립하였다. 1 단계: F9 EC세포에 스크리닝할 물질의 단독처리 2 단계: 스크리닝할 물질에 dibutyryl cyclic AMP(dbc-AMP)와 theophylline을 첨가하여 처리 3 단계: 분화 marker유전자의 발현조사 그리고 이 시스템을 이용하여 천연 식물 및 해양동식물에서 추출한 성분을 대상으로 하여 새로운 분화인자의 검색을 시도한 결과, saponin, steroid 및 glycolipid계열의 물질이 분화인자로서 효과가 있음이 나타났다.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.649-656
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• 2008

The current study was undertaken to investigate the mechanism of action of insulin-like growth factors (IGFs) on proliferation and differentiation of pig preadipocytes. The preadipocytes were isolated from the backfat of new-born female pigs and cultured in serum-deprived medium in the presence and absence of recombinant native IGFs or recombinant mutant IGFs that have reduced affinity for binding to both type-1 IGF receptors and insulin receptors. Fifty ng/ml of either IGF-I, [Leu60]IGF-I, IGF-Ⅱ or [Leu27]IGF-Ⅱ were included in the media in which preadipocytes were cultured for 4 days. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated proliferation of pig preadipocytes by 39%, 8%, 25% and 2% respectively, as measured by increased numbers of cells. This indicates that both IGF-I and -II promote replication of pig preadipocytes by actions mediated either by type-1 IGF receptor or insulin receptor. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated differentiation of pig preadipocytes by 50%, 17%, 37% and 30%, respectively, measured as glycerolphosphate dehydrogenase activity. Reducing the affinity of IGF-I for type-1 IGF receptors or insulin receptors significantly reduced the differentiation response. However, the differentiation response to [Leu27]IGF-II was not significantly different from the response to IGF-II. This shows that IGF-I and IGF-Ⅱ promote cell differentiation by different receptor-mediated mechanisms. IGF-II promotes differentiation of pig preadipocytes by actions that do not involve either type-1 IGF receptors or insulin receptors. These actions therefore appear to be mediated by binding of IGF-II to type-2 IGF receptors(also known as cation-independendent mannose-6-phosphate receptor[CIM6P/IGF2 receptor]). This is the first study to find evidence that IGF-II promotes differentiation of preadipocytes from any animal species by actions mediated by CIM6P/IGF2 receptors. In summary, this study shows that IGF-I and IGF-Ⅱ promote differentiation of pig preadipocytes by mechanisms that involve different cellular receptors.

• The Korean Journal of Zoology
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• v.38 no.1
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• pp.20-25
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• 1995

계배 limb bud 간충직 연골원성 세포로부터 연골세포로의 분화에 미치는 transforming growth factor-f2(TGF-$\beta$2)의 영향을 알아보기 위하여, Hamburger-Hamilton stages 23/24의 간충직 세포들을 미세배양법으로 배양하면서. TGF-$\beta$2의 농도 및 처리시간에 따른 연골세포의 분화에 미치는 영향을 조사하였다 그 결과 TGF-$\beta$2는 배양 첫 24시간 동안 1-2 ng/ml의 농도로 처리하였을 때 가장 효과적으로 연골세포의 분화를 촉진하였으며, 또한 TGF-$\beta$2의 처리군에서 배양 3일째에 tsss) sulfate의 glycosaminoglvcan으로의 유입량이 현저히 증가함을 보였다 한편. 배양 48시간내에TGF-$\beta$2를 처리한 경우 분화를 촉진 유도한 반면, 배양 48시간 이후에 처리하였을 때에는 분화 촉진 효과가 나타나지 않았다. 이상의 결과로부터 TGF-$\beta$2는 연골원 세포의 분화 초기단계에 세포외기질의 합성을 촉진시켜 세포응축을 유발하고. 세포-세포 및 세포-세포외기질의 상호작용을 증대시킴으로써 연골세포로의 분화를 촉진시킬 것으로 추정되었다.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.967-974
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• 2004

The current study was undertaken to determine the effect of various conjugated linoleic acid (CLA) isomers on differentiation of pig preadipocyte during culture. Preadipocyte(stroma-vascular cell) was isolated from the backfat of newborn pigs and cultured to differentiate into mature fat cell. Different doses of CLA isomers were treated to the culture media at different times. Cell differentiation was determined by measuring the glycerol3-phosphate dehydrogenase activity of the cultured preadipocytes. Twenty and fifty $\mu$M of trans110_cis 12 isomer of CLA inhibited differentiation of pig preadipocyte whereas cis9-cis II isomer stimulated the differentiation. Both cis9-transII and trans9-trans11 isomers showed no effect. Effect of CLA isomer was more evident at the early stage of culture(day 0-8), than the late stage(day 8-14). These results suggest that each CLA isomer has different effect on pig preadipocyte differentiation.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.460-468
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• 1991

계배 limb bud간충직 연골원성 세포로부터 연골원세포로의 분화과정에서 Ca2+의 역할을 추구해 보기 위하여 Hamburger-Hamilton stage 23/24의 계배 limb bud간충직세포들을 미세배양법으로 배양하면서, Ca2+, calcium ionophore인 A23187, calcium channel blocker인 D600을 각각 농도 및 처리기간을 변화시켜 처리하면서 연골화의 정도를 검정하여, 연골세포 분화에 미치는 Ca2+의 작용양상을 분석하였다. 그 결과 Ca2+은 3 mM의 농도로 배양초기에 처리하였을 때 가장 효과적으로 연골화를 촉진하였으며, A23187(0.05 $\mu$ M) 처리는 세포내로 Ca2+유입을 증가시켜 연골화를 촉진시킨 반면, D6OO(30 $\mu$ M이하) 처리는 세포내로 Ca2+ 유입을 차단시킴으로서 연골화를 억제하는 것으로 나타났다. 이러한 결과에 따른 세포내로의 칼슘 유입 변화는 45Ca로 확인하였다. 그러므로 Ca2+에 의한 간충직세포의 연골세포로의 분화촉진 작용은 Ca2+이 연골화의 응집시기에 세포간의 접촉을 유도할 뿐만 아니라 배양 초기에 Ca2+이 세포 내로 들어감으로써 수반되는 일련의 기작에 의한 것임을 알았다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.206-206
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• 1994

1차년도에 F9 EC cell의 분화유도 시스템을 확립한뒤 계속적으로 해양생물로 부터 분리한 여러가지 물질을 처리하여 세포의 형태 변화 및 분화 관련 유전자 즉 laminin Bl, type IV collagen, RAR-$\beta$ 의 발현을 조사하였다. 그 결과 다수의 물질이 F9 세포를 분화시키는데 효과가 있는 것으로 나타났으며, 효과있는 물질들에 대한 구조분석이 계속적으로 실시되고 있다. 뿐만 아니라 분화효과가 있는 물질중에서 그 구조적으로 특이한 성질을 가진 물질에 대하여 이 물질이 암세호의 분화에 미치는 기작에 대해 조사하였다. 구체적인 실험내용을 요약하면 다음과 같다. 1. F9 EC cell에 스크리링할 물질의 처리 후 형태 변화 관찰 2. 분화 maker 유전자의 발현 조사 3, 작용 기작에 대한 조사