• Molecules and Cells
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• 제37권7호
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• pp.562-567
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• 2014

Human Hertwig's epithelial root sheath/epithelial rests of Malassez (HERS/ERM) cells are epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the epithelial-mesenchymal transition via TGF-${\beta}1$. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

• Plant Biotechnology Reports
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• 제4권1호
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• pp.15-21
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• 2010

The over-expression of Arabidopsis CAX1 and CAX2 causes transgenic tomato plants to reveal severe $Ca^{2+}$ deficiency-like symptoms such as tip-burn and/or blossom end rot, despite there being sufficient $Ca^{2+}$ in each plant part. To correct the symptoms and to moderately enhance the calcium level, a worldwide vegetable tomato was genetically engineered using a modified Arabidopsis cation/$H^+$ antiporter sCAX2A, a mutant form of Arabidopsis CAX2. Compared with the wild-type, the sCAX2A-expressing tomato plants demonstrated elevated $Ca^{2+}$ levels in the fruits with almost no changes in the levels of $Mn^{2+}$, $Cu^{2+}$, and $Fe^{2+}$. Moreover, expression of sCAX2A in tomato plants did not show any significant alterations in their morphological phenotypes. Unlike 35S::sCAX1 construct, sCAX2A antiporter gene driven by 35S promoter can be a valuable tool for enriching $Ca^{2+}$ contents in the tomato fruit without additional accumulation of the undesirable cations.

• 한국수의병리학회지
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• 제6권1호
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• pp.41-48
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• 2002

Oval cell is considered as facultative precursor cells for both hepatocytes and biliary cells, as well as origin of hepatocellar and cholangiocellular carcinoma (CCC) during carcinogenesis or toxic liver injury. To clarify the cellular origin or differentiation of cholagiocarcinogensis, the fate of carcinogen-induced oval cells was pathologically and phenotypically chased in Syrian golden hamster liver after Clonorchis sinensis (CS) infection which would give rise to a promoting effect. Two week treatment of hamsters with 0.005% diethylnitrosamine (DEN) followed by 2 week treatment of 1% 2-acetylaminofluorene (AAF) under choline deficient diet resulted in massive proliferation of BrdU labeleed and PCNA positive oval cells showing various distinct morphology, histochemical and immunohistochemical phenotypes for GGT, cytokeratin 19 and OV-6. Oval cells also frequently form ductular-like structures or phenotypically show hepatocyte-like characteristics. After CS infection, the oval cells showed sequential morphological changes to atypicl proliferating bile ductules and all hamsters thereafter developed well differentiated and anaplastic CCC at 16 week after CS infection. In electron microscopy, some bile ductules were constructed by intermediate oval cells and bile ductular cells surrounded by basement membrane. The results of this study strongly suggest that CCC developed in the present study were originated from hepatic stem-like oval cells, supporting the theory of stem cell origin of cancers. In addition, this hamster model would be valuable for the molecular mechanistic study during chemical-triggered cholangiocarcinogenesis.

• 한국초지조사료학회지
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• 제11권1호
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• pp.1-5
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• 1991

Tall fescue(Festuca amndinacea Schreb.) is a productive pasture grass that is widely adapted to the soil and climate of Korea. It is regarded, however, as relatively low in palatability and nutritive value. On the other hand, Italian ryegrass(lo1ium rnultz$om Lam.) is highly nutritious and palatable, but is essentially weak in cold tolerance. Numerous investigators have succeeded in producing hybrids between Lolium spp. and Festuca spp. but no improved varieties have resulted. Therefore, intergeneric hybridization of Italian ryegrass with tall fescue is employed in 1984 to improve the adaptive and cold resistance quality of Italian ryegrass. In the mean time, F1-hybrid plants obtained by crossing Italian ryegrass x tall fescue were observed in open field. The results are summarized as follows: 1. Leaf-size and silica cell hair were intermediate between the types of parents but the shape of auricle tended to show Italian ryegrass and auricle-cilia to show tall fescue. 2. Roots of $F_1$-hybrid plants were mainly distributed at top soil and did not produced florescence material. 3. Head type of hybrids was intermediate between the types of parents but ray length was somewhat less than the length of tall fescue ray. Typical Italian ryegrass or tall fescue-like phenotypes were not observed. 4. Anthers of $F_1$-hybrid plants were formed but pollen were not formed. Even though pollen were formed, they were all empty. 5. Hybrid plants were more winterhardy and summer persistency than Italian ryegrass. They showed a equivalent growth to Italian ryegrass in spring and to tall fescue in summer. 6. Chromosome of $F_1$-hybrids was allopolyploid(2n=4~=28) and all $F_1$-hybrid plants were sterile.

• 한국재료학회지
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• 제20권3호
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• pp.155-160
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• 2010

In this study, we investigated primary biocompatibility and osteogenic gene expression of porous granular BCP bone substitutes with or without strontium (Sr) doping. In vitro biocompatibility was investigated on fibroblasts like L929 cells and osteoblasts like MG-63 cells using a cell viability assay (MTT) and one cell morphological observation by SEM, respectively. MTT results showed a cell viability percent of L929 fibroblasts, which was higher in Sr-BCP granules (98-101%) than in the non-doped granules (92-96%, p < 0.05). Osteoblasts like MG-63 cells were also found to proliferate better on Sr-doped BCP granules (01-111%) than on the non-doped ones (92-99%, p < 0.05) using an MTT assay. As compared with pure BCP granules, SEM images of MG-63 cells grown on sample surfaces confirmed that cellular spreading, adhesion and proliferation were facilitated by Sr doping on BCP. Active filopodial growth of MG-63 cells was also observed on Sr-doped BCP granules. The cells on Sr-doped BCP granules were well attached and spread out. Gene expression of osteonectin, osteopontin and osteoprotegrin were also evaluated using reverse transcriptase polymerase chain reaction (RT-PCR), which showed that the mRNA phenotypes of these genes were well maintained and expressed in Sr-doped BCP granules. These results suggest that Sr doping in a porous BCP granule can potentially enhance the biocompatibility and bone ingrowth capability of BCP biomaterials.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.9-9
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• 2021

Mutation breeding is useful for improving agronomic characteristics of various crops. In this study, we constructed soybean Mutant Diversity Pool (MDP) from 1,695 gamma-irradiated mutants through two selection phases over M1 to M12 generations; we selected 523 mutant lines exhibiting at least 30% superior agricultural characteristics, and, second, we eliminated redundant morphological phenotypes in the M12 generation. Finally, we constructed 208 MDP lines and investigated 11 agronomic traits. We then assessed the genetic diversity and inter-relationships of these MDP lines using target region amplification polymorphism (TRAP) markers. Among the different TRAP primer combinations, polymorphism levels and PIC values averaged 59.71% and 0.15, respectively. Dendrogram and population structure analyses divided the MDP lines into four major groups. According to an analysis of AMOVA, the percentage of inter-population variation among mutants was 11.320 (20.6%), whereas mutant inter-population variation ranged from 0.231 (0.4%) to 14.324 (26.1%). Overall, the genetic similarity of each cultivar and its mutants were higher than within other mutant populations. In an analysis of the genome-wide association study (GWAS) using based on the genotyping-by-sequencing (GBS), we detected 66 SNPs located on 13 different chromosomes were found to be highly associated with four agronomic traits: days of flowering (33 SNPs), flower color (16 SNPs), node number (6 SNPs), and seed coat color (11 SNPs). These results are consistent with those previously reported for other genetic resource populations, including natural accessions and recombinant inbred line. Our observations suggest that genomic changes in mutant individuals induced by gamma rays occurred at the same loci as those of natural soybean population. This study has demonstrated that the integration of GBS and GWAS can serve as a powerful complementary approach to gamma-ray mutation for the dissection of complex traits in soybean.

• 생명과학회지
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• 제20권1호
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• pp.22-26
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• 2010

벼의 적색 종피 표현형질은 Rc 혹은 Rd 그리고 RdRc 두 개의 복수유전자에 의하여 결정된다. 본 연구에서는 종피에 색소가 있는 돌연변이 벼 7계통을 벼 표현형 돌연변이 군들로부터 분리하였다. 이들 종피색의 돌연변이 형질을 조사한 결과 두 개의 변이체가 갈색의 종피형질을 가졌으며 네 개의 변이체가 적색의 종피형질을 가졌다. 그리고 한 개의 변이체는 종피에 색깔이 없었다. 수확 후 종자의 종피색 표현형질에 관한 정밀조사를 실시한 결과 두개의 갈색종피 돌변이체는 Rc 유전자형 이었으며 네개의 적색종피 돌변이체는 RdRc 유전자형이었다. 또한 종피에 색깔이 없는 한 개의 돌변이체가 Rd 유전자형이었다. 이들 중 동일한 종피색깔을 나타내는 돌연변이 개체들이 단일 돌연변이 개체의 후손인지 여부를 판명하기 위하여 돌변이체들의 초형과 농업형질을 조사한 결과 동일 종피색 돌변이체들의 형질이 서로 상이하므로 각각 서로 다른 돌연변이 계통들로 확인되었다. 그리고 이들 종피색깔 돌연변이들은 초형, 분얼 특징, 임성과 수량성 등을 포함한 농업형질들이 정상 벼의 농업형질들보다 대체로 빈약하고 또한 높은 탈립성을 보였다. 이러한 종피색과 관련된 돌연변이 벼 유전자원은 안토시아닌과 폴리페놀이 풍부하므로 병충해 저항성 품종과 환경스트레스 내성 품종의 육종에 필요할 뿐만 아니라 종피의 색깔을 결정하는 유전자들의 기능을 밝히는 데 중요한 자료로 사용될 것이다.

• 한국자원식물학회지
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• 제28권1호
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• pp.119-125
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• 2015

본 연구는 유채-MS를 이용하여 배추와 순무 등을 화분친으로 활용 잎의 모용이 없는 유채 잎에 배추와 순무의 엽색과 엽형을 도입하여 소비자가 선호하는 새로운 형질을 갖춘 엽채소의 작출 가능성을 검토하고자 실시하였다. 교배효율에 영향을 미치는 인공수분 후 주두 위에서의 화분발아나 화분관 신장은 유채-MS와 배추간 종간 교배 조합에서 유채-MS와 순무간 종간교잡보다 빠르게 진행되었으며, 유채-MS와 배추간 종간교잡에서의 결협율이 90.6%로 유채-MS와 순무의 교배 결협율 67.3% 보다 23.3% 정도 높게 나타났으며, 협당결실립수는 각각 15.5립, 11.6립으로 나타나 유채-MS와 배추간의 종간교잡 효율이 높았다. 유채-MS와 배추의 종간교잡 $F_1$ 잡종의 표현형질의 특성은 주로 모계인 유채와 비슷하였으며 엽색은 밝은 녹색으로 양친의 중간형을 나타냈고 모용은 적게 분포되어 있었으며 엽수는 10.2매, 엽장은 27.5 cm, 엽폭은 14.0 cm로 잎의 길이와 넓이가 유채에 비하여 커졌다. 유채-MS와 순무의 종간교잡 $F_1$ 잡종의 엽수는 9.6매, 엽장은 21.6 cm, 엽폭은 10.6 cm로 잎의 크기, 형태 및 결각 등은 양친의 중간형을 나타냈으며 엽색은 모본인 유채와 비슷하거나 좀 더 짙은 녹색이었고, 모용이 잎의 앞과 뒷면에 존재하였다.

• 한국자원식물학회지
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• 제35권4호
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• pp.464-470
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• 2022

산초나무 5개 품종의 꽃과 열매에 대해 형태적 특성을 조사한 결과, 화서의 너비와 암꽃잎의 길이는 품종에 따라 유의적 차이가 있었다. 또한 각 특성에 대한 기여도 확인을 위해 주성분을 확인한 결과, 제3주성분까지의 누적 설명력은 71.0%였고, 화서의 크기, 열매 송이의 크기, 암꽃잎의 크기, 종자의 무게, 종자 수는 높은 상관관계를 보였으며, 이러한 특성들은 품종을 설명하는데 있어 중요도가 높다고 사료된다. 분산분석 결과와 주성분 분석결과에서 화서의 너비, 암꽃잎의 길이 특성이 공통적으로 유의한 결과를 보였으며, 이 특성들은 품종 특성을 설명하는 데 있어 중요 형질이라 판단된다. 유집분석 결과 거리 수준 15를 기준으로 I그룹은 한초 915호, 1020호와 1030호로 가장 근접하였으며, 나머지 930호, 10호는 각각의 그룹으로 구분되었다. 그러나 질적 특성 결과에서 개화기와 결실기 차이가 확연하게 나타남으로 품종 간 구별되는 것을 확인할 수 있었다. 본 연구를 통해 산초나무의 꽃과 열매의 형태적 특성에서 품종 간 유연관계를 확인하였으며, 산초품종 육성을 위한 기초자료로 이용될 수 있을 것으로 사료되며. 향후 다양한 품종에서 유연관계를 설명을 위해 데이터 처리에 대한 기초자료로 이용될 것을 기대한다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2007년도 International Meeting of the Microbiological Society of Korea
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• pp.120-122
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• 2007

All living organisms use numerous signal-transduction pathways to sense and respond to their environments and thereby survive and proliferate in a range of biological niches. Molecular dissection of these signalling networks has increased our understanding of these communication processes and provides a platform for therapeutic intervention when these pathways malfunction in disease states, including infection. Owing to the expanding availability of sequenced genomes, a wealth of genetic and molecular tools and the conservation of signalling networks, members of the fungal kingdom serve as excellent model systems for more complex, multicellular organisms. Here, we employed Cryptococcus neoformans as a model system to understand how fungal-signalling circuits operate at the molecular level to sense and respond to a plethora of environmental stresses, including osmoticshock, UV, high temperature, oxidative stress and toxic drugs/metabolites. The stress-activated p38/Hog1 MAPK pathway is structurally conserved in many organisms as diverse as yeast and mammals, but its regulation is uniquely specialized in a majority of clinical Cryptococcus neoformans serotype A and D strains to control differentiation and virulence factor regulation. C. neoformans Hog1 MAPK is controlled by Pbs2 MAPK kinase (MAPKK). The Pbs2-Hog1 MAPK cascade is controlled by the fungal "two-component" system that is composed of a response regulator, Ssk1, and multiple sensor kinases, including two-component.like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. We also identified and characterized the Ssk2 MAPKKK upstream of the MAPKK Pbs2 and the MAPK Hog1 in C. neoformans. The SSK2 gene was identified as a potential component responsible for differential Hog1 regulation between the serotype D sibling f1 strains B3501 and B3502 through comparative analysis of their meiotic map with the meiotic segregation of Hog1-dependent sensitivity to the fungicide fludioxonil. Ssk2 is the only polymorphic component in the Hog1 MAPK module, including two coding sequence changes between the SSK2 alleles in B3501 and B3502 strains. To further support this finding, the SSK2 allele exchange completely swapped Hog1-related phenotypes between B3501 and B3502 strains. In the serotype A strain H99, disruption of the SSK2 gene dramatically enhanced capsule biosynthesis and mating efficiency, similar to pbs2 and hog1 mutations. Furthermore, ssk2, pbs2, and hog1 mutants are all hypersensitive to a variety of stresses and completely resistant to fludioxonil. Taken together, these findings indicate that Ssk2 is the critical interface protein connecting the two-component system and the Pbs2-Hog1 pathway in C. neoformans.