• 생명과학회지
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• 제28권8호
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• pp.985-991
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• 2018

생물시계(Biological clock)는 생명체에서 나타나는 반복되는 자율적인 리듬을 말하며, 단일세포는 물론 다세포 생명체의 기본적인 대사와 이에 따른 표현형과 행동을 직접적으로 조절하고 있다. 이러한 생물시계는 동면 리듬, 수면 리듬, 심장박동 리듬 및 짝짓기 노래 리듬 등 매우 다양하며, 24시간 이상의 주기를 infradian rhythm, 24시간 주기를 circadian rhythm, 24시간 이내의 짧은 주기를 ultradian rhythm으로 구분한다. 효모 Saccharomyces cerevisiae는 최소 5종 이상의 반복되는 자율적인 리듬이 알려져 있으며, 이중 일부는 생체시계로 인식되고 있다. 본 리뷰에서는 Saccharomyces cerevisiae의 glycolytic oscillation (T= 1~30분), cell cycle-dependent oscillation (T= 2~16 시간), ultradian metabolic oscillation (T= 15~50분), yeast colony oscillation (T= 수 시간) 및 circadian oscillation (T= 24시간)에 대한 연구 결과를 제시하고, 특히 ultradian metabolic oscillation의 특징, 집단 동조인자(population synchronizer), 동조인자의 조절 기작 및 효모 생물시계의 대사공학 분야의 이용성을 제시하여 효모를 이용한 동적 대사조절 및 생물시계 연구가 가능함을 제시하였다.

• 농업과학연구
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• 제20권2호
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• pp.189-200
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• 1993

Ornithine Decarboxylase는 동물세포에 있어서 polyamines을 생합성하는 반응의 율속 단계에 있는 효소이다. 세포의 성장기간 동안에 이 효소는 mRNA와 단백질 수준에서 급격한 변화를 일으키며 조절된다. 이와 같은 polyamines농도의 급변화를 분자수준에서 탐구하기 위하여 ODC 특이 cDNA colne이 cDNA libray에서 분리되었다. cDNA의 clone이 이루어진 부분은 open reading frame과 3'-noncording region, 그리고 poly A의 tail이 있는 부분으로서 각각 456, 348, 14개의 nucleotides로서 구성되어 있었다. 인간, mouse, rat, hamster로부터 같은 지역내 추론된 C-말단으로부터의 아미노산의 비교는 단백질 상동성에 88%이상을 보였다. 이와같은 아미노산 염기순서에 있어서의 잘 보존된 특징은 ODC가 세포성정과 분화에 있어서 중요한 역할이 있음을 잘 나타내고 있다.

• 대한수의학회지
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• 제15권1호
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• pp.57-67
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• 1975

The poxvirus group is considered to be a typical cytoplasmic inclusion forming virus. Every poxvirus has been reported to produce only one kind of inclusion in the infected tissues. A vague concept that inclusions of poxviruses are eosinophilic or acidophilic has prevailed. Although many papers and theories about the nature of the inclusion have been presented, most of them are not quite convincing on the point of the relations with virus multiplication, and an analysis of papers published showed that there seem to be many discrepancies in the descriptions of the nature of the poxvirus inclusions. Comparative studies on host-virus interaction with cowpox, orf, swinepox and fowlpox viruses which selected from each Group (I-IV) of poxviruses were performed from the morphological and virological standpoints. At first, in cowpox virus-FL cell system, as a comparative model, cytoplasmic inclusion, nucleic acid metabolism by autoradiography and detection of viral antigen by immunofluorescence were studied and obtained the results as follows: 1. The focus-like cytopathic effect (CPE) at early stage developed to entire culture at terminal stage of infection, and also the developing status of CPE was correlated to viral doses for inoculation. Two kinds of cytoplasmic inclusions which named A and B type were easily observed by Giemsa, hematoxylin-eosin (H & E) and May-Greenwald Giemsa (MGG) stainings in the infected cells. The B type inclusions were formed at early stage of infection and the A type inclusions were produced subsequently the B type formation. The B type which common type inclusion in poxviruses was a small compact or aggregate at early stage and developed to a large diffuse body at terminal stage of infection. On the other hand, the A type inclusion which depend upon the kind of virus was appeared as round and discrete shape, and its size and number was increased gradually during the culture period. It was characteristic to form distinct halos around the both types of inclusions in acid fixed, H & E stained preparations of infected cultures. The B type inclusion was always positive in Feulgen reaction and showed as DNA containing body but the A type inclusion was not. 2. In the relationship between inclusion and DNA metabolism of infected cells by the qualitative autoradiography using 3H-thymidine, the appearance of silver grains was coincided with B type inclusion but not with A type inclusion. This showed that the DNA synthesis was proceeded in all B type inclusions except those in the terminal stage with a diffuse form. This suggested that the B type inclusions are only sites of DNA synthesis and this was proceeded after the cell infection independently. The activity of DNA synthesis of the inclusions was nearly the same as that of the nucleic of normal cells and non-inclusion bearing cells. and non-inclusion bearing cells. Regardless of the size of the degree of DNA synthesis of the B type inclusion, inclusion bearing cells all showed remarkable suppression of nuclear DNA synthesis. 3. By the direct fluorescent antibody technique viral antigen in infected cells was detected. The B type inclusions have been proved to contain a great deal of viral antigen, whereas the basic substance of A type inclusion did not show antigenicity except the round edge. It was suggested that the round edge fluorescence might be caused by the glare of cytoplasmic viral antigen which pushed out and concentrated by the A type inclusion development. 4. Hemorrhagic red pock formations on chorioallantoic membrane of embryonated chicken egg had proved the characteristic of used viral strain. 5. By the above studies on the nature of two types of inclusions and the role they play in virus multiplication, it was concluded that the B type inclusion must be the site of the synthesis of viral DNA and protein as well as the site of the virus.

• 한국식품영양과학회지
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• 제33권7호
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• pp.1085-1091
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• 2004

먼저 OVA항원에 대해 특이적으로 증식반응을 나타내는 T세포주를 수립하였고, 수림된 세포주는 세포 표면 단백질이 CD4$^{＋}$CD8$^{-}$이며 IL-2와 IFN-${\gamma}$를 분비하는 Type I에 속하는 보조 T세포(Thl)인 것을 확인하였다. 보중익기탕의 total 분획은 OVA항원에 대해 특이적으로 반응하는 Thl세포의 증식반응을 증가시키는 효과를 나타내지 않았으며 고농도에서 오히려 증식반응을 억제하였다. 그러나, 보중익기탕의 polysaccharide 분획은 전반적 인 농도에서 T세포의 증식반응을 유의하게 증가시키는 효과가 있는 것으로 나타났다. 보중익기탕의 polysaccharide 분획을 첨가하였을 때 T세포의 IL-2 분비량은 대조군보다 약간 적었지만, IFN-${\gamma}$ 분비량은 대조군보다 증가하였다. 그리고, 분비된 IL-2와 결합하는 T세포의 IL-3 수용체 발현양도 증가하는 것으로 나타났다. 또한, 항원제시세포의 MHC class II의 발현양도 증가시켰다. 이상의 결과로 보중익기탕의 polysaccharide분획은 T세포의 IL-2수용체 발현양을 증가시키고, 항원제시세포의 MHC classs II의 발현양을 증가시켜서 T세포의 증식반응을 증가시키는것으로 생각된다 그리고 보중익기탕이 생체 면역반응에 미치는 보다 정확한 효과를 평가하기 위해서는 직접 살아있는 실험동물에 투여하는 in vivo 실험이 필요하다.

• 생명과학회지
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• 제25권7호
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• pp.833-838
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• 2015

다제약제 내성을 가지는 슈퍼 박테리아, 곰팡이, 바이러스, 기생충 감염은 주요한 건강위협인자들이다. 하지만, 건강위협 상황을 극복하기위해 현재 약제의 대안들중 항생펩타이드를 들 수 있다. 항생펩타이드는 자연계 다양한 종에서 생산된다. 항생펩타이드는 작은 단백질로 어류, 양서류, 파충류, 식물 그리고 동물의 감염으로부터 다세포생명체를 보호하는 선천성 면역에 관여하고 있다. 1980년대 이후로 매년 항생펩타이드의 수가 증가하고 있다. 박테리아, 원생생물, 곰팡이, 식물, 동물로부터 동정된 2,000가지 이상의 항생펩타이드가 항생펩타이드 데이터베이스에 등록되어 있다. 이러한 항생펩타이드의 대부분은 11-50개의 아미노산으로 구성되어 있고 하전상태는 0에서 +7까지이며 소수성은 31-70%를 차지하고 있다. 본 보고는 항생펩타이드를 생물학적 원천, 생물학적 기능, 펩타이드 성질, 공유결합패턴, 3차구조등에 의해 분류하였다. 항생펩타이드의 기능은 항균작용외에 세포주화성과 같은 세포생물학적 활성에도 기능성을 가지고 있다. 더욱이 림프절 스트로마로부터 기원한 fibroblastic reticular cell (FRC)에 염증상황 유도시 항생펩타이드가 발현되는 것을 확인하였다. FRC로부터 유도된 항생펩타이드는 whey acidic protein (WAP) 도메인을 포함하고 있었다. 이것은 단백질 도메인에 의해서도 항생펩타이드를 분류 할 수 있다는 것을 제시한다.

• 한국재료학회지
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• 제31권3호
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• pp.150-155
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• 2021

Zinc oxide (ZnO) based transparent conducting oxides (TCO) thin films, are used in many applications such as solar cells, flat panel displays, and LEDs due to their wide bandgap nature and excellent electrical properties. In the present work, fluorine and aluminium-doped ZnO targets are prepared and thin films are deposited on soda-lime glass substrate using a RF magnetron sputtering unit. The aluminium concentration is fixed at 2 wt%, and the fluorine concentration is adjusted between 0 to 2.0 wt% with five different concentrations, namely, Al2ZnO98(AZO), F0.5AZO97.5(FAZO1), F1AZO97(FAZO2), F1.5AZO96.5(FAZO3), and F2AZO96(FAZO4). Thin films are deposited with an RF power of 40 W and working pressure of 5 m Torr at 270 ℃. The morphological analysis performed for the thin film reveals that surface roughness decreases in FAZO1 and FAZO2 samples when doped with a small amount of fluorine. Further, optical and electrical properties measured for FAZO1 sample show average optical transmissions of over 89 % in the visible region and 82.5 % in the infrared region, followed by low resistivity and sheet resistance of 3.59 × 10-4 Ωcm and 5.52 Ω/sq, respectively. In future, these thin films with excellent optoelectronic properties can be used for thin-film solar cell and other optoelectronics applications.

• Animal cells and systems
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• 제3권2호
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• pp.207-213
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• 1999

During the differentiation of Naegleria gruberi amoebas into flagellates, the amoebas undergo sequential changes in cell shape and form new cellular organelles. To understand the nature of the signal which initiates this differentiation and the signal transduction pathway, we treated cells with four agents, PMA, retinoic acid (RA), okadaic acid, and cAMP. Retinoic acid and cAMP had specific effects on the differentiation of N. gruberi depending on the time of the drug treatment. Addition of (100$\mu$M) retinoic acid at the initiation of differentiation inhibited differentiation by blockinq the transcription of differentiation specific genes (e.g., $\beta$-tubulin). This inhibition of differentiation by retinoic acid was overcome by co-treatment with cAMP (or dbcAMP, 20 $\mu$M). Addition of retinoic acid at later stages (30 and 70 min) had no effect on the transcriptional regulation of the $\beta$-tubulin gene, however the differentiation was inhibited by different degrees. Co-treatment of cAMP at these stages did not overcome the inhibitory effect of retinoic acid. These results suggest that the role of retinoic acid as a transcriptional regulator might be conserved throughout the evolution of eukaryotes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.195-195
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• 2012

Recently, graphene based solution-gated field-effect transistors (SGFETs) have been received a great attention in biochemical sensing applications. Graphene and reduced graphene oxide (RGO) possess various advantages such as high sensitivity, low detection limit, label-free electrical detection, and ease of fabrication due to their 2D nature and large sensing area compared to 1D nanomaterials- based nanobiosensors. Therefore, graphene or RGO -based SGFET is a good potential candidate for sensitive detection of protons (H+ ions) which can be applied as the transducer in various enzymatic or cell-based biosensing applications. However, reports on detection of H+ ions using graphene or RGO based SGFETs have been still limited. According to recent reports, clean graphene grown by CVD or exfoliation is electrochemically insensitive to changes of H+ concentration in solution because its surface does not have terminal functional groups that can sense the chemical potential change induced by varying surface charges of H+ on CVD graphene surface. In this work, we used RGO -SGFETs having oxygen-containing functional groups such as hydroxyl (OH) groups that effectively interact with H+ ions for expectation of increasing pH sensitivity. Additionally, we also investigate RGO based SGFETs for bio-sensing applications. Hydroloytic enzymes were introduced for sensing of biomolecular interaction on the surface of RGO -SGFET in which enzyme and substrate are acetylcholinesterase (AchE) and acetylcholine (Ach), respectively. The increase in H+ generated through enzymatic reaction of hydrolysis of Ach by AchE immobilized on RGO channel in SGFET could be monitored by the change in the drain-source current (Ids).

• 한국수산과학회지
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• 제54권2호
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• pp.162-169
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• 2021

Global warming has affected the distribution of organisms for decades and has displayed rapid ascent recently. Research into the effects on tropical organisms are vital. Padina boryana is a resourceful marine microalgae in the Maldives Sea in the Laccadive region. A 70% ethanol extraction (PBE) of this seaweed was used to investigate its antioxidant potential. Both in vitro and in vivo models were implemented. PBE exhibited protective potential against H₂O₂ induced apoptosis. ROS levels were suppressed due to PBE. PBE expressed a cytoprotective nature. In vivo experiments involving the zebra fish model conformed its validity. The antioxidant efficacy of PBE was dose dependent. Study outcomes suggest PBE has potential as a novel and valuable marine resource to aid the functional food and cosmeceutical industries.

• 한국자원식물학회지
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• 제24권1호
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• pp.23-29
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• 2011

본 연구는 새로운 기능성 소재를 탐색하기 위하여 튤립나무 가지의 메탄올 추출물을 조제하여 생리활성 물질 함량, DPPH, 환원능력, $Fe^{2+}$ chelating효과와 지질과산화 억제 활성 그리고 세포독성을 측정하였다. 총 페놀성 화합물과 플라보노이드 함량은 75.34 mg gallic acid/g과 20.15 mg quercetin/g이고; DPPH 라디칼 소거 활성에서 $EC_{50}$은 $289.68{\pm}2.04 \;{\mu}g$/mL; 환원력 측정에서 $100\;{\mu}g$/mL 농도에서 흡광도는 0.388이었으며, $Fe^{2+}$ chelating 효과에서는 $200\;{\mu}g$/mL 농도에서 36.33%로 나타내었고, 지질과산화 억제 효능에서는 $200\;{\mu}g$/mL의 농도에서 비교적 높은 38.56%의 억제율을 나타내었으며, 암세포 증식 억제 효과에서는 HT-29와 Hela cell line에서 튤립나무가지 메탄올 추출물이 $200\;{\mu}g$/mL의 농도에서 56.94%와 35.73%의 세포생장 억제율을 나타내었다. 따라서 본 연구 결과들을 종합해 볼 때 항산화능력은 총 페놀성분과 밀접한 관계가 있는 것으로 사료되며, 튤립나무 가지에 대한 기타 생리활성 연구가 더 필요할 것으로 사료된다.