• 식물조직배양학회지
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• 제22권3호
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• pp.131-135
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• 1995

잡종 사기나무의 기내 대량증식을 목적으로 줄기절간 유래의 기내 및 기외시료를 이용하여 다경줄기 유도에 관여하는 식물생장 조절물질의 효과에 대하여 조사하였다. 기외시료의 측아를 제거한 다음 20에서 30$\mu$M 의 zeatin이 함유된 WPM 배지에 6주간 배양하였을때 각각 11개와 13개의 다경줄기가 유도되었다. 그러나 기외시료의 측아가 붙어있는 상태에서 기내배양하여 2주후에 측아를 제거하고 동일 배지에 배양하였을 경우에는 BA가 1.0에서 2.0 $\mu$M 함유된 배지에서도 13개와 15개의 다경줄기를 유도할 수 있었으며, 특히 이때 생산된 줄기의 상태는 아주 건전한 것으로 나타났다. 기내줄기를 사용하였을때는 20 $\mu$M의 zeatin을 처리하였을때 가장 많은 줄기를 생산할 수 있었으며, 생산된 조직배양묘는 일정기간 순화를 시킨 후 온실이나 포지에 식재가 가능하였다.

• 식물조직배양학회지
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• 제22권6호
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• pp.335-337
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• 1995

주목의 줄기절간 조직배양에 의한 다경줄기 유도를 위해 식물생장조절물질 중 4가지 형태의 싸이토키닌 효과를 조사 한 바, BAP, kinetin 및 thidiazuron의 경우 거의 반응을 보이지 않았으나, zeatin을 5 $\times$ $10^{-5}$M 처리하였을 경우 평균 6 개 이상의 다경줄기를 얻을 수 있었으며, 배양시료에 따라서 는 12개 이상의 다경을 형성하는 경우도 관찰되었다. 유도된 다경줄기를 지속적으로 계대배양하여 줄기를 신장시킨 후 이로부터 2 cm 크기의 기내삽목도 가능하였다. 기내발근율은 LP기본배지를 이용하는 것이 비교적 양호하였으나 효율은 3%에 지나지 않았다. 기외발근의 경우, 약 34%까지 발근율을 올릴 수 있었으며 포지에 이식시킨 조직배양묘는 1년이상 정상적인 생육을 보이고 있음이 관찰되었다.

• 공학교육연구
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• 제20권3호
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• pp.13-24
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• 2017

This study investigated student engagement of STEM-specialized higher education institutions in comparison with students from humanities & social science and STEM majors, respectively. By doing so, the study aimed to find the effects of the characteristics of STEM disciplines and organizational culture of STEM-specialized small-sized institutions on student engagement. The students majoring STEM disciplines, regardless of the organizational types, showed lower reflective-integrative learning experiences compared to students on humanities & social science disciplines. In contrast, students of STEM-specialized institutions reported significantly higher levels of peer relationship and student-faculty interaction in comparison with humanities & social science students and STEM students of general higher education institutions. Finally, the study suggests policy implications for STEM education.

• BMB Reports
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• 제50권11호
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• pp.572-577
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• 2017

In most clinical applications, human mesenchymal stem cells (hMSCs) are expanded in large scale before their administration. Prolonged culture in vitro results in cellular senescence-associated phenotypes, including accumulation of reactive oxygen species (ROS) and decreased cell viabilities. Profiling of stem cell-related genes during in vitro expansion revealed that numerous canonical pathways were significantly changed. To determine the effect of selenocysteine (Sec), a rare amino acid found in several antioxidant enzymes, on the replicative senescence in hMSCs, we treated senescent hMSCs with Sec. Supplementation of Sec in the culture medium in late-passage hMSCs reduced ROS levels and improved the survival of hMSCs. In addition, a subset of key antioxidant genes and Sec-containing selenoproteins showed increased mRNA levels after Sec treatment. Furthermore, ROS metabolism and inflammation pathways were predicted to be downregulated. Taken together, our results suggest that Sec has antioxidant effects on the replicative senescence of hMSCs.

• Mycobiology
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• 제28권4호
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• pp.180-184
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• 2000

In order to find an environment-friendly method to suppress astragal stem rot caused by the isolates of Rhizoctonia solani AG 1 and AG 4, we tested an antagonistic fungus Gliocladium virens G1 was evaluated as a biocontrol agent and estimated inorganic compounds and organic materials were tested for their effect of the disease suppression. G. virens G1 effectively inhibited mycelial growth in a dual culture and caused mycelial lysis in the culture filtrate. No adverse effect was observed when examined for seed germination and seedling growth. Promoted seedling growth was observed with the seed treatment. Seeds of astragal plant were germinated higher in the sterile soil than the natural soil. Of 14 inorganics tested, alum, aluminum sulfate and calcium oxide significantly suppressed the mycelial growth and sclerotial germination. Milled pine bark and oak sawdust also suppressed the mycelial growth. Soil amended with 1% of G. virens G1 composted with pine bark (w/v) significantly controlled astragal stem rot in the glasshouse experiments.

• Biomolecules & Therapeutics
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• 제24권3호
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• pp.260-267
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• 2016

Mesenchymal stem cells (MSCs) offer significant therapeutic promise for various regenerative therapies. However, MSC-based therapy for injury exhibits low efficacy due to the pathological environment in target tissues and the differences between in vitro and in vivo conditions. To address this issue, we developed adipose-derived MSC spheroids as a novel delivery method to preserve the stem cell microenvironment. MSC spheroids were generated by suspension culture for 3 days, and their sizes increased in a time-dependent manner. After re-attachment of MSC spheroids to the plastic dish, their adhesion capacity and morphology were not altered. MSC spheroids showed enhanced production of hypoxia-induced angiogenic cytokines such as vascular endothelial growth factor (VEGF), stromal cell derived factor (SDF), and hepatocyte growth factor (HGF). In addition, spheroid culture promoted the preservation of extracellular matrix (ECM) components, such as laminin and fibronectin, in a culture time- and spheroid size-dependent manner. Furthermore, phosphorylation of AKT, a cell survival signal, was significantly higher and the expression of pro-apoptotic molecules, poly (ADP ribose) polymerase-1 (PARP-1) and cleaved caspase-3, was markedly lower in the spheroids than in MSCs in monolayers. In the murine hindlimb ischemia model, transplanted MSC spheroids showed better proliferation than MSCs in monolayer. These findings suggest that MSC spheroids promote MSC bioactivities via secretion of angiogenic cytokines, preservation of ECM components, and regulation of apoptotic signals. Therefore, MSC spheroid-based cell therapy may serve as a simple and effective strategy for regenerative medicine.

• International Journal of Stem Cells
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• 제16권2호
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• pp.244-249
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• 2023

Background and Objectives: To examine whether ischemic retinal ganglion cells (RGCs) will be salvaged from cell death by human adipose-derived mesenchymal stem cells (ADSCs) in an organotypic retina model. Methods and Results: Deprived of arterial oxygen supply, whole mice retinas were cultured as an ex vivo organotypic cultures on an insert membrane in a 24-well plate. The therapeutic potential of ADSCs was examined by co-culture with organotypic retinas. ADSCs were seeded on top of the RGCs allowing direct contact, or at the bottom of the well, sharing the same culture media and allowing a paracrine activity. The number of surviving RGCs was assessed using Brn3a staining and confocal microscopy. Cytokine secretion of ADSCs to medium was analyzed by cytokine array. When co-cultured with ADSCs, the number of surviving RGCs was similarly significantly higher in both treatment groups compared to controls. Analysis of ADSCs cytokines secretion profile, showed secretion of anti-apoptotic and pro-proliferative cytokines (threshold>1.4). Transplantation of ADSCs in a co-culture system with organotypic ischemic retinas resulted in RGCs recovery. Since there was no advantage to direct contact of ADSCs with RGCs, the beneficial effect seen may be related to paracrine activity of ADSCs. Conclusions: These data correlated with secretion profile of ADSCs' anti-apoptotic and pro-proliferative cytokines.

• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1447-1460
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• 2009

Myogenic satellite cells have been isolated and identified by several recently elucidated molecular markers. Furthermore, knowledge about the precise function of these markers has provided insight into the early and terminal events of satellite cells during proliferation, differentiation, transdifferentiation, specification and activation. Recently, quiescent myogenic satellite cells have been associated with possession of Pax 3 and 7 that represent pluripotent stem cells capable of differentiating into other lineages. However, the mechanism by which myogenic satellite cells attain pluripotent potential remain elusive. Later, transdifferentiating ability of these cells to another lineage in the absence or presence of certain growth factor/ or agents has revolutionized the scope of these pluripotent myogenic satellite cells for manipulation of animal production (in terms of quality and quantity of muscle protein) and health (in terms of repair of skeletal muscle, cartilage or bone).

• 생물환경조절학회지
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• 제8권4호
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• pp.232-241
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• 1999

본 논문에서는 온실재배 토마토에서 수분 상태를 고려한 정밀한 관개를 위하여 경직경의 변화에 근거한 자동관개 시스템을 구현하고자 하였으며 이와 같은 작물적 지표에 의한 관개제어시스템을 포트재배(closed feeding system) 조건과 포장재배 조건의 재배에 적용하여 토마토의 수량과 과실의 품질에 대하여 그 적합도를 평가하였다. 작물적 지표에 의한 관개 자동화를 위하여 경직경 측정 센서를 이용하여 측정한 경직경 일증가량(DI)를 관개 개시점의 결정에 이용하고, 동시에 이때의 관개량을 결정하기 위하여 토마토 증산모델을 적용한 마이크로 컴퓨터 자동관개 시스템을 구현하고 그 성능을 평가하였는데, 이 자동 관개 시스템을 이용하여 관개처리한 결과 포트재배에서는 토양수분에 의한 관개방식보다 수량 및 과실의 당도가 증가하였으나 포장조건에서는 관개방법간에 큰 차이가 없었다. 따라서 경직경 증가에 근거한 관개 개시점을 판단하고 관계량을 결정하는 증산모델을 사용하는 컴퓨터 시스템은 특히 closed feeding System에서 유용하며 토양조건에서는 토양의 상태, 작물의 반응 등을 고려하여 적용하여야 할 것으로 판단되었다.

• Journal of Plant Biotechnology
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• 제4권1호
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• pp.33-37
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• 2002

Micropropagation and adventitious root production via the culture of Polygonatum odoratum were performed. Stem segments of seedlings of Polygonatum odoratum were the most efficient explants for adventitious shoot formation compared to leaf and root segments. Exogenous cytokinin treatment was required for adventitious shoot formation. Among the cytokinin (BA, Kinetin and Zeatin) tested, BA was most effective for shoot formation from stem segments. Auxin (NAA or IBA) in combination with cytokinin significantly enhanced adventitious shoot formation. Twenty five percent of explants produced adventitious shoots on medium with 2.0 mg/L BAP alone, while 83% of explants produced adventitious shoots on medium with the combination of 2.0 mg/L BAP and 0.1 mg/L IBA. Rooting of adventitious shoots was achieved after transferring to 112 MS medium supplemented with 0.1 mg/L IBA and 0.5 mg/L zeatin. When stem segments were cultured on MS medium with various kinds of auxin (IBA, NAA and 2,4-D), adventitious roots were formed from callus. frequency of adventitious root formation was highest in 2,4-D than NAA and IBA. When roots were in clusters together with parental stem segments, growth of roots actively occurred in hormone-free MS liquid medium. The above results represent that possible application for the mass production of roots and plantlets through in vitro culture system of Polygonatum odoratum.