• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.273-280
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• 1999

Hypocotyl explants of Medicago saliva cv. Vernal were cultured on Murashige and Skoog (MS) medium supplemented with various combinations of growth regulators. After six weeks of culture, somatic embryos were formed from calli on MS medium containing $4mg/{\ell}$ 2,4-D and $0.1mg/{\ell}$ kinetin, or $4mg/{\ell}$ 2,4-D and $0.5mg/{\ell}$ kinetin. The mature somatic embryos were developed to plantlets when subcultured on MS basal medium. In order to obtain secondary somatic embryogenic calli, cotyledon of regenerated plantlets were cultured on a callus induction medium. Embryogenic calli were formed on MS medium containing $4mg/{\ell}$ 2,4-D alone. For induction and development of secondary somatic embryogenesis, the embryogenic calli were transferred to MS basal medium containing either 2,4-D or NAA. Multi-secondary somatic embryogenesis was the most effective on MS basal medium with $0.1mg/{\ell}$ 2,4-D. The rate of secondary somatic embryo formation of regenerated plants was 18 times higher than that of seed grown plants. The mature secondary somatic embryo were germinated into plantlets on MS basal medium after six weeks of culture.

• Journal of Plant Biotechnology
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• v.50
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• pp.155-162
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• 2023

Radish (Raphanus sativus L.), a root vegetable grown worldwide, is consumed in several ways. In the cross between parental lines to produce F1 seeds of radish, the problem of low purity may arise because of pollen contamination. Therefore, we aimed to establish conditions for callus induction and regeneration so that in vitro cultured plants could be used for the propagation of stock seeds. The most effective hormone combination containing various concentrations of 2,4-D, TDZ, and kinetin was selected for callus induction using radish hypocotyl, and the induced calli were transferred to two types of hormone media to investigate the optimal conditions for shoot regeneration of the callus. The combination of 1 mg/L 2,4-D + 0.05 mg/L kin was the most effective for callus induction of RA2 and RA10, 1 mg/L 2,4-D + 0.1 mg/L kin + 0.025 mg/L TDZ of RA4, and 1 mg/L 2,4-D + 0.2 mg/L kin of RA30. Shoot regeneration of the RA4 callus occurred in both shoot regeneration media, but the frequency was much higher in the 5H+1B medium (1 mg/L NAA + 0.1 mg/L 2,4-D + 1 mg/L IPA + 0.02 mg/L GA3 + 2 mg/L zeatin + 1 mg/L BA). For the in vitro micropropagation of radish, the conditions selected in this study can assist in the propagation and maintenance of stock seeds to produce F1 seeds.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1215-1221
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• 2000

Objective : The clinical prognosis and biological behavior of atypical and especially malignant meningiomas are well known to be worse than benign meningioma, but the degree of biological aggressiveness in each classical subtypes of benign meningioma is controversy. This study was performed to see whether there is a difference in the proliferative activity between each different histological subtypes of benign meningioma as well as atypical meningioma. Methods : Paraffin-embedded surgical specimens of 27 meningiomas, including two recurrent tumors, were studied to evaluate proliferative activity by immunohistochemical method with monoclonal antibodies to proliferating cell nuclear antigen(PCNA) and MIB-1. The specimens consisted of 8 cases of meningothelial, 9 cases of transitional, 5 cases of fibroblastic subtypes and 5 cases of atypical meningiomas. Results : Mean PCNA labeling indices of meningothelial, transitional and fibroblastic meningiomas were $4.82{\pm}5.10%$, $9.01{\pm}4.25%$ and $5.66{\pm}5.32%$, but that of atypical meningiomas was $27.62{\pm}19.67%$, noting a higher value compared to all three subtypes of benign meningiomas. Mean Ki-67 labeling indices of the above 3 subtypes were $0.43{\pm}0.85%$, $0.44{\pm}1.08%$ and $0.24{\pm}0.18%$, and that of atypical meningiomas was also revealed to be of higher value ($0.84{\pm}0.59%$). PCNA and Ki-67 labeling indices were not statistically different between histological subtypes of benign meningioma(p>0.05), but the differences of both immunolabeling between benign and atypical meningiomas were statistically significant(p<0.05). Conclusion : Immunolabeling of PCNA and Ki-67 in intracranial meningiomas reveals no prognostic difference between meningothelial, transitional and fibroblastic subtypes in classical benign meningiomas by measuring expression of PCNA and Ki-67, but it seems to be helpful in differentiating benign and atypical meningioma, later showing more proliferative activity and biological aggressiveness.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.335-339
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• 2003

The aim of this study is to optimize the monolayer cultivation of human articular chondrocytes in serum-free media. For this purpose, chondrocytes were isolated from human articular cartilage and monolayer cultures were performed in DMEM/F12 medium with 10% fetal bovine serum (FBS) or serum-free media (SFM) containing various supplements and epidermal growth factor (EGF). Western blotting analysis, RT-PCR, dimethylmethylene blue (DMB) assay were carried out to evaluate the synthesis of collagen type II (Col. II) and glycosaminoglycans (GAGs). We observed that SFM with EGF stimulated the cell growth while the amounts of synthesized GAGs and Col. II were decreased gradually. However, the Col. II mRNA level was increased when the SFM was replaced by media containing 10% FBS. This study suggests that it is possible to obtain large amount of human articular chondrocytes by short-term monolayer cultures in SFM.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.358-360
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• 1998

Series of in vitro experiments in Lilium callosum were conducted to investigate efficient multiplication through finding the optimal cultural environment, and organogenic capability of cultural explants, and then to determine the progressive method for enhancing bulblet growth in Lilium callosum scale culture. Twenty-four hr photoperiod was most effective for the growth of bulblet and the formation of other organs. Optimum light intensity for bulblet growth was 2,500~5,000 Lux. When bulbets were subcultured, growth of bulblets were enhanced by removing excessive leaf blade. Number of bulblets per scale increased as mother scale size increased, whereas diameter of bulblet from the small size mother scale increased. Bulblet formation and development was induced when explants were placed above the medium to be exposed to more light.

• Parasites, Hosts and Diseases
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• v.33 no.2
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• pp.131-134
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• 1995

When tachyzoites (RH strain) of Toxoplasmo gondii are injected intramuscularly, experimental mice survive up to 7 days, 1-2 days longer than those infected intraperitoneally. We observed sequential histopathological changes in inguinal Iymph nodes after intramuscular injection of tachyzoites to thighs of specific pathogen free (SPF) mice. Initial findings on 1 or 3 days after the injection were reactive germinal centers, distended sinuses and epithelioid cell clusters in cortical and paracortical regions. Later on 5 days after the injection, however, effacement of nodal structure with depletion of cells and focal necrosis were observed . Necrotizing Iymphadenitis in the experimental murine toxoplasmosis suggests the causal relation between T. gondii infection and the human disease.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.57-57
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• 2001

Erythropoietin(EPO)는 혈액의 구성성분 중에서 적혈구 세포 증식에 중요한 기능을 한다고 알려져 있으며, 최근에는 암, 에이즈의 치료 등에도 효과가 있는 것으로 확인되고 있다. 따라서 본 연구팀은 지금까지 hEPO 유전자를 이용하여, 형질전환 돼지 "새롬이"의 생산에 성공한바 있다. 새롬이의 정액을 활용하여 인공수정을 실시 새롬이의 Fl를 24두 생산하였다. 이에 대하여 "형질전환 돼지의 계대번식시 유전자 전이효율에 관한 연구"라는 제목으로 발표 할 예정이며, 형질전환에 사용된 promoter가 WAP이므로, Fl이 임신, 분만을 하여야만 유즙을 통하여 hEPO물질을 생산할 수 있다. 따라서, Fl(♂)$\times$Fl(♀)의 교배에 의하여 5두가 임신, 분만을 하였으며, 이들 중 1두는 분만 후 21일에 폐사하였으며, 나머지는 현재 정상적으로 사육되고 있다. 이들 5두에 대하여 분만 후 유즙을 채취하여 유즙속에 EPO의 발현여부를 검토하였다. EPO-ELISA kit(medac)를 사용하여 분석결과, 유즙을 8,000배로 희석을 하여야만 Standard curve(1.25~160 mIU/$m\ell$)안에서 EPO의 단백질 발현을 검출할 수 있었다. 5두의 각각 농도는 28, 58, 17, 37, 27 IU/${\mu}\ell$ 였다. 또한 cDNA EPO와 genome EPO를 CHO 동물세포에서 생산하여 10배로 농축한 결과 5.5와 11 IU/${\mu}\ell$의 농도로 유즙과 비교하면 약 20~30배의 낮은 발현양을 나타내었으며, 또한 이러한 결과는 소변에서의 결과(1.1 IU/$m\ell$)보다는 약 30,000배 이상 높은 발현량을 화인 할 수 있었다. 현재, 이들 유즙 물질을 활용 빈혈 질환실험동물을 이용하여 생리활성을 검정, 체내에서 metabolic clearance rate(MCR)를 검토 중에 있다. 또한 F2의 자돈생산은 모돈 5두에서 총 25두가 생산되었는데, 이중 20두 약 80%가 EPO 유전자의 전환율을 나타내었다. 이상을 종합하면, 1) 돼지이용 생리활성물질(EPO)을 유즙에서 대량으로 생산할 수 있는 system의 활용가능성을 국내에서 처음으로 확인하였으며, 2) EPO에 있어서는 국제적으로도 형질전환 가축생산은 최초로 성공하였으며, 현재로서는 생산되어진 물질의 정제수준에 따라 활용가치가 결정되어 질 것으로 사료된다. 생리활성 물질을 생산할 수 있는 형질전환 돼지 생산의 성공은, 앞으로 형질전환 가축생산 뿐 만 아니라, 장기이식 및 복제돼지 생산의 활용 면에서의 응용가능성이 기대된다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.38-38
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• 2018

최근 호두 기내 소비량은 급증하나 대부분 실생묘로 조림되어 결실까지 장기간 소요되며, 무성 번식률이 낮아 보급확대가 어렵다. 본 연구는 호두나무 관행 묘목 번식법 개선이 가능한 우량 국산묘 대량증식 기술 개발로 최적 배양조건을 구명하고자 수행하였디. 호두나무 등 목본류는 식물 조직배양 기본배지에서 산화방지제를 첨가하여 사용하는 경우, 배양체에서 생기는 페놀 화합물(Phenolic compound)의 작용을 억제하여 배양 식물체의 갈변(Browning) 또는 흑변(Blackening) 현상을 감소시키는 효과가 있다. 페놀 추출물은 배지로 빠져나와 갈변시키며 생존율을 저하시키는 원인이 되고 이를 제거하는 산화방지제는 배양 식물체의 생산효율을 높이는 효과를 나타내는 강력한 항산화제(Antioxidant) 역할을 한다. 호두나무의 액아를 배양하게 되면 조직 및 배지의 갈변화가 심하게 일어나는데, 휴면 정도가 깊을 수록 정단에서 추출되는 페놀성 물질의 함량이 증가하며, 식물 조직 내 페놀성 물질의 함량 정도와 배양의 고사율과는 상관관계가 있다. 이러한 식물 배양체에서 생기는 페놀 화합물에 의해 발생되는 배양상의 문제점을 해결하기 위하여 계대배양을 자주해 주거나 활성탄(Activated charcoal), Ascorbic Acid 등의 첨가물을 배지에 추가하는 방법이 있다. 이에 따라 호두 '신령' 품종의 액아배양의 페놀집적을 제거하기 위해 배지 내에 산화방지제 첨가물질 등을 농도별로 처리하였다. 호두나무 액아 배양 후 8주차 산화화방지제 첨가물질의 농도별 처리 효과는 생존율은 85.3%를 보였으며, 신초 형성율 76.4%, 신초수 1.9개/주, 신초장 27mm/주의 양호한 결과를 나타냈으며, 페놀 제거 및 유식물체 고사 억제 효과를 보였다.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.99-105
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• 2002

A gregarious pupal endoparasitoid Tetrastichsus sp. (Hymenoptera: Eulophidae) was reared in vitro from oviposition to adult emergence on an artificial host. The host pupal case was made using 0.02 mm-thick polypropylene film, and was filled with a diet consisting of powders of Antheraea pernyi pupa, chicken yolk, infant formula, royal jelly, and Neisenheimer's salt solution. Female parasitoids reared in the artificial host produced smaller sized progeny than those reared in in vivo, but the adults reproduced fertile offsprings. Furthermore in vitro second-generation (G$_2$) females showed more improved biological characteristics, compared with their parents. The fecundity (mean no. adult progeny), oviposition period (days), and longevity (days) of G$_2$ female were evaluated as 45.7, 7.8, and 13.8, respectively Female biased sex ratio was obtained with 76.9% female progeny. The results demonstrated that Tetrastichus sp. is a promising parasitoid for in vitro mass production.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.277-281
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• 2001

Embryogenic callus induction and plant regeneration methods were developed for native Kentucky bluegrass (Poa pratenes L.) ecotypes. Mature caryopses and immature inflorescences (20 mm in length) of 4 native ecotypes and 5 foreign cultivars were plated on MS medium (30 g/L sucrose, 3 g/L Phytagel) supplemented with 1 mg/L 2,4-D, and cultured in the dark at 24$^{\circ}C$. Most explants formed calli, but more embryogenic calli were induced from the explants of immature inflorescences than caryopses which produced mostly non-embryogenic rooty calli. In P77 ecotypes, immature inflorescence explants formed embryogenic calli with the rate of 62~95%, and those of field-grown plants were more efficient than greenhouse-grown ones in embryogenic callus induction. Plantlets were regenerated from the embryogenic calli when they were transferred to hormone-free MS medium, and grew to maturity without morphological variations in greenhouse.