• 산업식품공학
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• 제13권1호
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• pp.44-49
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• 2009

Angelicae gigantis Radix (dried root of Angelica gigas) including major bioactives such as decursin and decursinol angelate provides rich flavors and several healthy benefits. Recent studies have shown that ultrafine powders of herbal medicines provide better physical properties and biological activities. Thus, ultrafine Angelica powder was added into the oligosaccharide syrup to provide flavors and healthy benefits in this study. Angelicae gigantis Radix was pulverized into d(0.1) = 3.220, d(0.5) = 7.822, and d(0.9) = 7.817 $\mu$m respectively using an air-flow mill. The ultrafine Angelica powder was added into the oligosaccharide syrup process with different ratios of water to oligosaccharide syrup at 1:5, 1:8, 1:11, and 1:14. The physicochemical properties such as viscosity and bulk density were measured. The Stokes' law was applied to predict the sedimentation velocity of the added Angelica powder in the syrup. The Angelica syrup prepared in this experiment showed good stability since the Angelica particles precipitated down slowly. The ratio of water to oligosaccharide syrup at 1:11 showed the optimal preparation in terms of the stability and the viscosity. The ultrafine-sized herbal powders such as Angelicae gigantis Radix have potentials for various food and pharmaceutical applications.

• Advances in nano research
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• 제10권4호
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• pp.359-371
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• 2021

A tumor immune interaction is a main topic of interest in the last couple of decades because majority of human population suffered by tumor, formed by the abnormal growth of cells and is continuously interacted with the immune system. Because of its wide range of applications, many researchers have modeled this tumor immune interaction in the form of ordinary, delay and fractional order differential equations as the majority of biological models have a long range temporal memory. So in the present work, tumor immune interaction in fractional form provides an excellent tool for the description of memory and hereditary properties of inter and intra cells. So the interaction between effector-cells, tumor cells and interleukin-2 (IL-2) are modeled by using the definition of Caputo fractional order derivative that provides the system with long-time memory and gives extra degree of freedom. Moreover, in order to achieve more efficient computational results of fractional-order system, a discretization process is performed to obtain its discrete counterpart. Furthermore, existence and local stability of fixed points are investigated for discrete model. Moreover, it is proved that two types of bifurcations such as Neimark-Sacker and flip bifurcations are studied. Finally, numerical examples are presented to support our analytical results.

• 자원환경지질
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• 제54권1호
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• pp.137-150
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• 2021

서악동 마애여래삼존입상은 경주 선도산 정상부의 동남향에 조성된 통일신라시대의 거석불로 입지적 중요성과 함께 힘찬 아미타불상과 부드러운 협시보살의 조각수법이 매우 특징적이다. 특히 안산암질 암반에 불신을 새기고 흑운모화강암을 대좌로 장식한 아미타불상과 좌우 병렬식으로 배치된 알칼리 화강암으로 조성된 협시불은 석재의 색상 및 질감을 통해 석불의 위엄을 잘 표현하였다. 아미타불상은 암반에 형성된 절리로 인한 불연속면의 발달과 사면의 불안정성, 최상부에서 발생하는 식물의 근압에 의한 암반의 이완현상이 결부되어 손상이 가속되고 있다. 또한 절리와 균열 및 박리 등 불연속면의 증가로 인해 물성이 크게 저하되었으며 조류 및 지의류의 피복도가 높은 상태이다. 따라서 마애여래삼존입상에 발생한 손상정도는 아미타불상이 마애불로 조성되면서 나타난 물리적 풍화특성과 다양한 생물침해에 의해 손상이 가속화되는 것으로 판단된다.

• Animal cells and systems
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• 제8권3호
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• pp.213-220
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• 2004

MicroRNA and siRNA (small interfering RNA), representative members of small RNA, exert their effects on target gene expression through association with protein complexes called miRNP (microRNA associated ribonucleoproteins) and RISC (RNA induced silencing complex), respectively. Although the protein complexes are yet to be fully characterized, human EIF2C2 protein has been identified as a component of both miRNP and RISC. In this report, we raised antiserum against EIF2C2 in order to begin understanding the protein complexes. An immunoblot result indicates that EIF2C2 protein is ubiquitously expressed in a variety of cell lines from human and mouse. EIF2C2 protein exists in both cellular compartments, as indicated by an immunoblot assay with a nuclear extract and a cytosolic fraction (S100 fraction) from HeLa S3 lysate. Depletion of EIF2C1 or EIF2C2 protein resulted in a decrease of microRNA, suggesting a possible role of these proteins in microRNA stability or biogenesis. We also prepared antiserum against dsRNA binding protein PACT, whose homologs in C. elegans and Drosophila are known to have a role in the RNAi (RNA interference) pathway. The expression of PACT protein was also observed in a wide range of cell lines.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.662-671
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• 2015

To enrich the genetic resource of microbial xylanases with high activity and stability under alkaline conditions, a xylanase gene (xynSL4) was cloned from Planococcus sp. SL4, an alkaline xylanase-producing strain isolated from the sediment of soda lake Dabusu. Deduced XynSL4 consists of a putative signal peptide of 29 residues and a catalytic domain (30-380 residues) of glycosyl hydrolase family 10, and shares the highest identity of 77% with a hypothetical protein from Planomicrobium glaciei CHR43. Phylogenetic analysis indicated that deduced XynSL4 is closely related with thermophilic and alkaline xylanases from Geobacillus and Bacillus species. The gene xynSL4 was expressed heterologously in Escherichia coli and the recombinant enzyme showed some superior properties. Purified recombinant XynSL4 (rXynSL4) was highly active and stable over the neutral and alkaline pH range from 6 to 11, with maximum activity at pH 7 and more than 60% activity at pH 11. It had an apparent temperature optimum of 70℃ and retained stable at this temperature in the presence of substrate. rXynSL4 was highly halotolerant, retaining more than 55% activity with 0.25-3.0 M NaCl and was stable at the concentration of NaCl up to 4M. The enzyme activity was significantly enhanced by β-mercaptoethanol and Ca²⁺ but strongly inhibited by heavy-metal ions and SDS. This thermophilic and alkaline- and salt-tolerant enzyme has great potential for basic research and industrial applications.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.320-323
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• 2003

본 연구에서는 형질전환된 식물세포배양으로 생산한 (hGM-CSF)를 cationic exchange resin인 CM-sepharose와 anionic exchange resin인 DEAE-sepharose에 통과키며 pH의 변화를 주었을 때 흡착 여부를 확인하였다. hGM-CSF는 pH가 5-7사이의 범위에서 가장 안정함을 보였으며 이 결과를 바탕으로 각각의 pH 범위를 결정하였다. Buffer exchange를 했을 때 cationic exchange resin인 CM-sepharose의 경우 pH 4.8에서 상대적으로 가장 높은 흡착율(77%)을 보였으며 anionic exchange resin인 DEAE-sepharose를 이용한 흡착에서는 pH 5.5에서 높은 흡착율(74%)을 보였다. 이러한 결과를 바탕으로 buffer exchange 없이 hGM-CSF가 secretion된 배지를 pH를 맞춘 후 좁은 범위에서의 흡착 실험을 수행하였다. 그 결과 pH 4.6에서 CM-sepharose를 이용했을 때 흡착율이 84%로 가장 좋았다. 이러한 결과를 이용하면 외래 단백질을 생산하는 식물세포 배양시에 가장 문제가 되는 protease에 의한 목적 단백질의 degradation을 해결할 수 있는 in situ adsorption이 가능하리라 사료된다.

• 공업화학
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• 제26권1호
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• pp.47-52
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• 2015

본 연구에서는 다중벽탄소나노튜브(multi-walled carbon nanotube, MWCNTs) 기반 바이오센서 전극의 포도당 산화효소(glucose oxidase, GOD) 담지능을 높여 그 민감도를 개선하고자 그래핀 옥사이드(graphene oxide, GO)를 첨가하여 전극을 제조하였다. GO 첨가로 인하여 MWCNTs의 분산뿐만 아니라 전극의 친수성 및 표면에너지가 증가하였다. 또한, MWNCTs 0.05 g에 GO 0.05 g를 첨가하였을 때 $K_m$ (Michaelis-Menten constant)이 0.105로 가장 높은 값을 나타냈음에도 불구하고 GOD 담지능이 높아졌으며, 민감도가 $121{\mu}A\;mM^{-1}$까지 향상됨을 알 수 있었다. 이러한 실험 결과는 GO첨가에 의한 MWCNTs의 분산 안정성 향상, MWCNTs 전극 표면에서 친수성으로 개질 및 표면 자유에너지 증가가 GOD 담지능에 영향을 미친 것으로 사료된다.

• 한국균학회지
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• 제27권6호
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• pp.399-405
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• 1999

${\alpha}-amylase$ 생산력이 우수한 야생형인 S. fiburigera의 핵을 순수분리하여 영양요구성 변이주인 S. cerevisiae(tyr-, ura-)의 원형질체에 전달하는 핵전이를 이용하여 종간잡종을 형성시킨 후 이들 형질전환체로부터 ${\alpha}-amylase$ 고생산 균주를 획득하였다. 핵전이를 위한 원형질체 형성 및 재생조건에서는 Novozym 234의 농도 1%, 삼투안정제는 0.6M KC1, 효소처리 시간은 90분, 그리고 최적 pH는 5.8로 나타났다. 핵전이에 의한 형질전환율은 0.25%로 비교적 낮은 편이었으며, 유전적 안정성, 세포크기의 체적, DNA함량의 측정 그리고 핵염색의 결과 형질전환체의 핵형은 aneuploid로 추정되었다. 형질전환 체의 ${\alpha}-amylase$ 활성은 모균주와 비교하여 약 $1.2{\sim}1.9$배 증가하였다.

• 한국환경과학회지
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• 제22권12호
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• pp.1551-1559
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• 2013

This study was conducted to compare benthic macroinvertebrate communities of urban stream and nature stream in Daegu-si, Gyeongju-si, Gyeongsan-si, Andong-si, and Cheongsong-gun. The survey was carried out with 12 points in total six points for urban stream, six points for nature stream from Sept. 2011 to July 2012. In the urban stream were 33 species belonged to 24 families, 11 orders, 7 classes and 4 phyla while in the nature stream were 73 species belonged to 38 families, 12 orders, 5 classes and 4 phyla. In general, species diversity indices and species richness indices appeared low in urban stream but dominance indices was high. Functional feeding groups and Habitat Oriented Groups appeared comparatively simple in urban stream rather than nature stream. As a result of analysis of community stability, species included to area I and area III equally appeared in nature stream while species included to area I mostly appeared in urban stream. An analysis of the correlation between the population density and the number of species, the population number and biological indicators such as DI, H', RI, and ESB revealed that there was a significant correlativity with the diversity index and a very high correlativity with the number of species, abundance index and the ESB. On the other hand, the population number and the dominance index did not reveal any correlativity. For indicator species, Hydroptila KUa, Physa acuta appeared in urban stream while Paraleptophlebia chocolata, Epeorus pellucidus appeared in nature stream.

• KSBB Journal
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• 제30권3호
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• pp.103-108
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• 2015

Production of foreign proteins by transgenic plant cell cultures has several advantages such as post-translational modification, low risk of product contamination and low-cost production and purification. However, target proteins are degraded by extracellular proteases existing in the media. A solution to this problem is the use of perfusion culture and ion exchange chromatography for the application of integrated bioprocess using in situ recovery. With this method, production of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) was investigated in this study. First, optimization of cell concentration during the induction phase for the production of hGM-CSF was examined. As cell concentration increased, the level of hGM-CSF was decreased due to the presence of extracellular proteases. Induction using sugarfree media produced 33% more hGM-CSF. The effects of pH on the binding of hGM-CSF to cationic and anionic exchange resins were also investigated. In terms of stability, optimal pH was found to be 5~7. In the case of using buffer exchange when CM-Sepharose was used as a cationic exchange resin, optimal pH for binding was 4.8 and adsorption yield was 77%. When DEAE-Sepharose was used as an anionic exchange resin, it was 5.5 (74%). Without buffer exchange, optimal pH was 4.6 (84%). From these results, an integrated bioprocess using in situ recovery with simultaneous production and separation of foreign protein in transgenic plant cell suspension cultures was found to be feasible.