• Animal cells and systems
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• 제2권2호
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• pp.287-295
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• 1998

The Saccharomyces cerevisiae MGMT gene encodes a O6-methylguanine DNA methyltransferase that protects cells from mutation or death by DNA alkylating agents. Using an in vitro transcription system, we analyzed its promoter region to find regulatory elements for transcription initiation. DNase I footprinting and a transcription assay showed that a functional TATA box, 5'-TGATATAGCA-3', is located in the region spanning from -25 to -34. We also found one upstream repressing sequence (URS), -333 to -213, by promoter deletion and competition analysis. Gel mobility shift assays and Southwestern blot analysis using URS region indicate specific complex formations. These results indicate that several cis-acting and trans-acting elements might be involved in the transcriptional regulation of the S. cerevisiae MGMT gene.

• 한국전기전자재료학회논문지
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• 제30권8호
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• pp.491-495
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• 2017

We investigated solution-processed indium-zinc oxide (IZO) thin-film transistors (TFTs) by inserting a 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) buffer layer. This buffer layer efficiently tuned the energy level between the semiconducting oxide channel and metal electrode by increasing charge extraction, thereby enhancing the overall device performance: the IZO TFT with embedded PBD layer (thickness: 5 nm; width: $2,000{\mu}m$; length: $200{\mu}m$) exhibited a field-effect mobility of $1.31cm^2V^{-1}s^{-1}$, threshold voltage of 0.12 V, subthreshold swing of $0.87V\;decade^{-1}$, and on/off current ratio of $9.28{\times}10^5$.

• 생명과학회지
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• 제7권4호
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• pp.289-296
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• 1997

Antioxidative activity of fraction extracted from cultivation of Aspergillus sp. A-5 against oxidation of human low density lipoprotein(LDL) was investigated. Fractions of Aspergillus sp. A-5 cultivation was sucessively purified with ethyl acetate and silica gel column chromatography. The concentration of fraction 4 inhibited Cu$^{2+}$-induced oxidation of LDL almost completely. Band 3 isolated by the further purification of fraction 4 was higher than that of same concentration of $\alpha$-tocopherol, BHA and BHT. The elcetrophoretic mobility of oxidized LDL by addition of Band 3 was faster than that of native LDL, but slower than that of oxidzed LDL. It is concluded that fraction of Aspergillus cultivation contained antioxidants with the capacity to inhibit oxidative modification of LDL.

• 미생물학회지
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• 제30권4호
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• pp.291-298
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• 1992

비변성 폴리아크릴 아미드 겔에서 Streptomyces coelicolor 의 catalase 활성 염색을 실시하여 여러개의 catalase 활성 띠를 관찰하였으며, 그 유형이 성장기에 따라 달라짐을 알았다. 포자와 정체 성장기에는 정체 성장기에만 특이적인Cat1(760kD) 이 관찰되었고, Cat2(300kD) 를 제외한 모든 활성 띠들이 나타났다. 중기 대수 성장기에는 Cat2 와 Cat 3-2, Cat3-2(140kD) 등 2개의 catalase 띠가 나타나며, 후기 대수 성장기에는 Cat3-1(170 kD), Cat3-2, Cat3-3(130kD). Cat4(70kD)등의 활성 띠가 나타났다. NTG 처리로 돌연변이화된 S. coelicolor 의 포자를 Bennet 평판 배지네서 배양한 후 과산화수소 거품 test 를 실시하여, 약 5000 여개의 콜로니 중 거품형성 속도나 양이 감소한 콜로니를 12개 얻었다. 야생형에 견주어 대부분 catalase 활성이 감소하였으며, 대수 성장기와 정체 성장기에서 모두 감소하였다. 거품형헝을 하지 않는 모든 돌연변이에서 Cat3-2 띠의 강도라 현저히 약해저 있음으로 보아 Cat3-2가 주된 catalase 인 것으로 추정된다. 대수 성장기에서 수확한 S. coelicolor 세포 추출액에서 Sepharose CL-4B, DEAE Sepharose CL-6B, Phenyl Sepharose CL-4B, Hydroxylapatite 크로마토그래피등 4단계의 크로마토그래피를 수행하여 Cat3-2 를 정제하였다. 비변성 폴리아크릴마드 겔 전기 영동을 수행한 결과 Cat3-2 는 67 kD 의 동일한 subunit 을 2개 가지고 있는 효소로 추정된다.

• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.214-218
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• 2020

In this study, Mg_xZn_1-xO thin films, which can be applied not only to active layers of light-emitting devices (LEDs), such as UV-LEDs, but also to solar cells, high mobility field-effect transistors, and power semiconductor devices, are fabricated using the sol-gel method. ZnO and Mg_0.3Zn_0.7O solution synthesized by the sol-gel method and the thin film were grown by spin coating on a Si (100) substrate and sapphire substrate. The solutions are synthesized by dissolving precursor materials in 2-methoxyethanol (2-ME) solvent, and then monoethanolamine (MEA) was added to the mixed solution as a sol stabilizer. Zinc acetate dihydrate is used as a ZnO precursor, while Mg nitrate hexahydrate and Mg acetate tetrahydrate are used as an MgO precursor. Then, the optical and structural characteristics of the fabricated thin films are compared. The molar concentration of the Zn precursor in the solvent is fixed at 0.3 M, and the amount of the Mg precursor is 30% of Mg²⁺/Zn²⁺. The optical characteristics are measured using an UV-vis spectrophotometer, and the transmittance of each wavelength is measured. Structural characteristics are measured using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Composition analyses are performed using energy dispersive X-ray spectroscopy (EDS). The Mg_0.3Zn_0.7O thin film was well formed at the ratio of the Mg precursor added regardless of the type of Mg precursor, and the c-axis of the thin film was decreased, while the band gap was increased to 3.56 eV.

• Applied Biological Chemistry
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• 제36권6호
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• pp.547-552
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• 1993

대두 종자 저장 단백질의 일종인 ${\beta}-conglycinin$ ${\alpha}'$ subunit 유전자의 upstream 지역에 결합하여 전사 조절에 관여하리라 추정되는 대두 핵의 DNA 결합 단백질을 조사하기 위하여 대두 핵 추출물과 S-100을 조제하였다. 염기서열이 AACCCA-27 bp-AACCCA인 합성 DNA를 pUC19에 클로닝한 플라스미드 pSE3를 EcoRI과 HindIII로 절단하여 절편을 분리하고 $^{32}P$ 로 표지하여 이를 gel mobility shift assay 탐침으로 이용한 결과, 대두 핵의 DNA 결합 단백질의 일종인 SEF3(soybean embryo factor 3)의 역가가 핵 추출물과 S-100에서 검출되었다. 각각 CATGCAT, AACACA 염기 서열을 가지는 DNA를 탐침으로 이용하여 SEF3 이외의 DNA 결합 단백질의 역가를 조사한 결과 대두 핵 추출물과 S-100에서 각기의 염기 서열에 결합하는 수 종의 DNA 결합 단백질이 확인되었으나 두 시료에서 공통된 양상을 보여주는 DNA 결합 단백질의 역가는 확인되지 않았다. 또한 대두 S-100의 경우에는 개화 후 32일 부근에 SEF3 역가가 검출되는 데에 비하여, 핵 추출물에는 20일 전후에 SEF3 역가가 나타나서 32일 부근에 역가가 현저히 증가하였다.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1841-1847
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• 2007

We previously identified the origin of replication of p703/5, a small cryptic plasmid from the KBL703 strain of Enterococcus faecalis. The origin of replication contains putative regulatory cis-elements required for replication and a replication initiator (RepA) gene. The replicon of p703/5 is similar in its structural organization to theta-type plasmids, and RepA is homologous to a family of Rep proteins identified in several plasmids from Gram-positive bacteria. Here, we report molecular interactions between RepA and the replication origin of p703/5. DNase I footprinting using recombinant RepA together with electrophoretic mobility shift assays confirmed the binding of RepA to the replication origin of p703/5 via iterons and an inverted repeat. We also demonstrated the formation of RepA dimers and the different binding of RepA to the iteron and the inverted repeat using gel filtration chromatographic analysis, a chemical crosslinking assay, and electrophoretic mobility shift assays in the presence of guanidine hydrochloride. Our results suggest that RepA plays a regulatory role in the replication of the enterococcal plasmid p703/5 via mechanisms similar to those of typical iteroncarrying theta-type plasmids.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.112-115
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• 2010

Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat technique using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resistivity ($\rho$), carrier concentration (n), and hall mobility ($\mu$) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity ($8.5 \times 10^{-2}$ ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility.

• 한국동물학회지
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• 제22권4호
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• pp.153-164
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• 1979

A total of 352 specimens of congeneric species of Agkistrodon was collected and morphometric analysis and starch-gel electrophoresis were carried out in order to investigate the taxonomic status of this genus. The results obtained in this study are as follows: Morphometric analysis 1. Three species are recognized based on Gloyd's criteria. There was no specimen that was doubtful to classify correctly. Therefore, it seems that Gloyd's morphological characters are good criteria to identify each species. 2. All three species are sympatric at two localities (Mt. Seolag, Gangwon-do, and Mt. Deogyu, Jeonra-bugdo) and A. caligino년 and A. b. brevicaudus are sympatric at Gwangneung and Mt. Yongmun, Gyonggi-do. No hybrids were found in these sympatric localities. 3. Notable sexual dimorphism was found in meristic characters. 4. A. saxatilis has signicantly more number of ventrals and shorter tail ratio than other two species. 5. There were no significant meristic character differences between A. caligino년 and A. b. brevicaudus. Genetic analysis 1. Among 26 loci investigated, 12 loci (46.1%) were identical in their mobility, 4 loci (15.4%) were nearly identical with minor frequency differences, and 10 loci (38.5%) showed interspecific mobility difference. 2. The average proportion of polymorphic loci was 9.03%. This is considerably less than that of other vertebrates. 3. The average S and D values between species are .695 and .342 respectively. These values indicate that three taxa are distinct species. 4. A. caliginosus is genetically more related to A. saxatilis than to Agkistrodon, namely A. b. brevicaudus, A. caligino년 and A. saxatilis, as proposed by Gloyd. Far from being mere morphological variants, as suggested by Kang and Yoon (1975), they are highly distinctive evolutionary units.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.37-37
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• 2010

Silicate-silsesquioxane or siloxane-silsesquioxane hybrid thin films are strong candidates as matrix materials for ultra low dielectric constant (low-k) thin films. We synthesized the silicate-silsesquioxane hybrid resins from tetraethoxyorthosilicate (TEOS) and methyltrimethoxysilane (MTMS) through hydrolysis and condensation polymerization by changing their molar ratios ([TEOS]:[MTMS] = 7:3, 5:5, and 3:7), spin-coating on Si(100) wafers. In the case of [TEOS]:[MTMS] 7:3, the dielectric permittivity value of the resultant thin film was measured at 4.30, exceeding that of the thermal oxide (3.9). This high value was thought to be due to Si-OH groups inside the film and more extensive studies were performed in terms of electronic, ionic, and orientational polarizations using Debye equation. The relationship between the mechanical properties and the synthetic conditions of the silicate-silsesquioxane precursors was also investigated. The synthetic conditions of the low-k films have to be chosen to meet both the low orientational polarization and high mechanical properties requirements. In addition, we have investigated a new solution-based approach to the synthesis of semiconducting chalcogenide films for use in thin-film transistor (TFT) devices, in an attempt to develop a simple and robust solution process for the synthesis of inorganic semiconductors. Our material design strategy is to use a sol-gel reaction to carry out the deposition of a spin-coated CdS film, which can then be converted to a xerogel material. These devices were found to exhibit n-channel TFT characteristics with an excellent field-effect mobility (a saturation mobility of ${\sim}\;48\;cm^2V^{-1}s^{-1}$) and low voltage operation (< 5 V). These results show that these semiconducting thin film materials can be used in low-cost and high-performance printable electronics.