• 폴리머
• /
• 제36권4호
• /
• pp.461-469
• /
• 2012

아르곤(Ar) 플라즈마 처리된 폴리프로필렌 복합소재의 표면 개질 및 특성 변화를 X-선 광전자 분광 분석(XPS), 적외선 분광 분석(FTIR), 주사 전자 현미경 분석(SEM) 및 접촉각 측정 등을 이용하여 조사하였다. Ar 플라즈마 처리 시간의 증가는 폴리프로필렌 복합소재 표면의 젖음성, 극성 관능기를 갖는 산소 성분, 탈크 함량 및 표면조도의 증가를 초래하였다. 주사 전자 현미경 분석을 통한 자세한 관찰은 폴리프로필렌 성분으로 구성된 표면층(skin layer)이 존재함을 확인하였다. 폴리프로필렌과 고무 입자간의 점도차는 표면층의 생성을 촉진시켰다. 하지만 Ar 플라즈마 처리시간의 증가는 표면층의 두께를 감소시키는 것을 확인하였다. 사출성형 공정 동안, 표면층을 제거할 수 있는 추가적인 방법론에 대해서도 토의하였다. Ar 플라즈마 처리에 의한 표면 개질 및 모폴로지의 변화는 폴리프로필렌 복합소재 표면 상에 친수화 상태를 부여하고, 이에 따라 젖음성 향상을 유도하였다.

• 폴리머
• /
• 제33권4호
• /
• pp.273-283
• /
• 2009

고분자소재의 표면 특성 중의 하나인 스크래치 거동에 관한 최근의 연구 결과와 현황을 광범위하게 고찰하였다. 본 고찰에서는 고분자 소재의 스크래치 특성에 영향을 주는 실험인자들, 즉 소재재질, 온도, 작용하중, 실험속도, 표면처리, 스크래치 횟수, 고분자 구조 및 관능기, 가교정도 그리고 결정화도에 따른 스크래치 특성을 조사하였다. 또한, 고분자 소재의 스크래치 특성을 정량적으로 평가할 수 있는 접근 방법을 소개하였고, 현존하는 관련 국제시험법을 비교 조사하였다. 고분자 소재의 스크래치 거동을 정확히 평가할 수 있는 방법과 내스크래치성을 향상시킬 수 있는 방법에 관한 최근의 기술적 접근 방법에 대해 토의하였다.

• Journal of Ginseng Research
• /
• 제44권2호
• /
• pp.321-331
• /
• 2020

Background: The patatin-related phospholipase AIII family (pPLAIIIs) genes alter cell elongation and cell wall composition in Arabidopsis and rice plant, suggesting diverse commercial purposes of the economically important medicinal ginseng plant. Herein, we show the functional characterization of a ginseng pPLAIII gene for the first time and discuss its potential applications. Methods: pPLAIIIs were identified from ginseng expressed sequence tag clones and further confirmed by search against ginseng database and polymerase chain reaction. A clone showing the highest homology with pPLAIIIβ was shown to be overexpressed in Arabidopsis using Agrobacterium. Quantitative polymerase chain reaction was performed to analyze ginseng pPLAIIIβ expression. Phenotypes were observed using a low-vacuum scanning electron microscope. Lignin was stained using phloroglucinol and quantified using acetyl bromide. Results: The PgpPLAIIIβ transcripts were observed in all organs of 2-year-old ginseng. Overexpression of ginseng pPLAIIIβ (PgpPLAIIIβ-OE) in Arabidopsis resulted in small and stunted plants. It shortened the trichomes and decreased trichome number, indicating defects in cell polarity. Furthermore, OE lines exhibited enlarged seeds with less number per silique. The YUCCA9 gene was downregulated in the OE lines, which is reported to be associated with lignification. Accordingly, lignin was stained less in the OE lines, and the expression of two transcription factors related to lignin biosynthesis was also decreased significantly. Conclusion: Overexpression of pPLAIIIβ retarded cell elongation in all the tested organs except seeds, which were longer and thicker than those of the controls. Shorter root length is related to auxinresponsive genes, and its stunted phenotype showed decreased lignin content.

• Plant Resources
• /
• 제8권1호
• /
• pp.60-66
• /
• 2005

Lysine is the first essential amino acid for optimal nutrient quality in rice grain. For the narrow genetic diversities of lysine contents in rice, somaclonal variation was the source of mutation in our breeding program. Biochemical selection was conducted using 1 mM S-(2-aminoethyl) cysteine followed by two passages of 5 mM lysine plus threonine in the callus subculture medium. The lysine contents in endosperm of all progenies recovered from the biochemical selection were higher than those of their donor cultivar 'Hwayeongbyeo'. These elevated lysine levels of mutants were successfully transmitted to $M_4$ generation. The lysine contents in endosperm varied 3.85 to $4.80\%$ compare to their donor cultivar 'Hwayeongbyeo' was $3.85\%$. Three of high-lysine germplasms, Lys-l, Lys-2 and Lys-7 were selected by biochemical selection and rapid screening methods. DNA analysis showed that a new insertion of Tos 17 which mapped to rice chromosome 11 on the high-lysine mutant, Lys-2.

• 한국자원식물학회지
• /
• 제16권3호
• /
• pp.257-263
• /
• 2003

더덕의 재배는 수익성이 높고 재배면적도 증가하지만 수요를 만족시킬 만큼 공급이 따르지 못하고 있다. 또한 재 배 상의 어려운점은 병충해, 기계수확에 의한 대규모 재배를 더욱더 곤란하게 하고 있는 실정이다. 이러한 문제점 및 환경적 스트레스에 저항하여 자랄 수 있는 식물체를 얻기 위해 더덕의 cDNA를 분석하여 스트레스 관한 유전자 Nucleoside diphosphates kinase 1(NDK 1)을 분리하여 분석하여 148개의 아미노산 서열과 다른 식물체들의 NDK 1과 높은 유사성을 가진다는 것을 알았고, 더덕의 각 조직에서 나타나는 ClNDK1의 발현을 알아보기 위해 캘러스, 잎, 줄기, 뿌리 조직의 전체 RNA를 추출하여 cDNA를 합성하고 PCR을 수행하였다 RT­PCR 분석 결과, ClNDK1은 조직 특이성 없이 캘러스, 잎, 줄기, 뿌리 조직에 대해서 모두 발현이 되었으며, 발현량, 역시 큰 차이 없이 모든 조직에서 동일하게 발현되었다. NDKs 는 환경 스트레스에 저항성을 가진다고 알려져 있지만 NDK 1 대한 연구는 아직까지 부족한 상태이다. 우리는 더덕에서 분리한 ClNDK1의 스트레스 저항성에 대해서 지속적으로 연구를 수행 할 것이다.

• 한국식품과학회지
• /
• 제36권2호
• /
• pp.211-216
• /
• 2004

회분식 반응기(stirred-tank batch reactor)를 사용한 DAG, MAG 함유 기능성유지를 비용매계(solvent-free system) 조건에서 효소적 반응을 이용하여 합성하였다. 48시간 동안 합성된 지질을 HPLC를 사용한 TAG, 1,3-DAG, 1,2-DAG 및 MAG 함량 분석결과 각각 45.05, 16.27, 23.05 및 14.98%로 분석되었으며 체중개선 기능성 유지의 지방산 조성 분석결과 palmitic, palmitoleic, stearic, oleic, linoleic 및 linolenic acid가 13.21, 0.15, 2.02, 34.36, 49.12 및 1.14 mol%로 분석되었다. 합성된 지질의 ${\alpha},\;{\gamma}$ 및 ${\delta}-tocopherol$ 함량을 분석한 결과는 각각 0.014, 0.029 및 0.010%로 분석되었으며 총 tocopherol 함량은 0.053%로 나타났다. 또한 재구성된 지질을 사용하여 산가, 비누화가, 요오드가를 측정하였으며 융점 및 결정화점을 살펴보고 이를 통하여 옥수수유로 유래된 DAG, MAG를 함유한 체중개선 기능성 유지의 이화학적, 물리적 특징을 규명하였다. 체중개선 기능성 유지의 산화 안정성 실험을 시행한 결과 체중개선 기능성 유지가 원료유인 옥수수유보다 높은 과산화물가와 p-anisidine가를 보였으며 각기 달리 혼합한 rosemary추출물(100, 200 및 300ppm)이 체중개선 기능성 유지와 옥수수유의 산화를 감소 시켰다.

• Molecules and Cells
• /
• 제38권2호
• /
• pp.187-194
• /
• 2015

Thioredoxin (TRX) is a disulfide reductase present ubiquitously in all taxa and plays an important role as a regulator of cellular redox state. Recently, a redox-independent, chaperone function has also been reported for some thioredoxins. We previously identified nodulin-35, the subunit of soybean uricase, as an interacting target of a cytosolic soybean thioredoxin, GmTRX. Here we report the further characterization of the interaction, which turns out to be independent of the disulfide reductase function and results in the co-localization of GmTRX and nodulin-35 in peroxisomes, suggesting a possible function of GmTRX in peroxisomes. In addition, the chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including the thermal denaturation assay and malate dehydrogenase aggregation assay. Our results demonstrate that the target of GmTRX is not only confined to the nodulin-35, but many other peroxisomal proteins, including catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), and acyl-coenzyme A oxidase 4 (AtACX4), also interact with the GmTRX. Together with an increased uricase activity of nodulin-35 and reduced ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin that is co-localized to the peroxisomes, possibly providing functional integrity to peroxisomal proteins.

• Molecules and Cells
• /
• 제38권10호
• /
• pp.866-875
• /
• 2015

COPI vesicles are essential to the retrograde transport of proteins in the early secretory pathway. The COPI coatomer complex consists of seven subunits, termed ${\alpha}-$, ${\beta}-$, ${\beta}^{\prime}-$, ${\gamma}-$, ${\delta}-$, ${\varepsilon}-$, and ${\zeta}$-COP, in yeast and mammals. Plant genomes have homologs of these subunits, but the essentiality of their cellular functions has hampered the functional characterization of the subunit genes in plants. Here we have employed virus-induced gene silencing (VIGS) and dexamethasone (DEX)-inducible RNAi of the COPI subunit genes to study the in vivo functions of the COPI coatomer complex in plants. The ${\beta}^{\prime}-$, ${\gamma}-$, and ${\delta}$-COP subunits localized to the Golgi as GFP-fusion proteins and interacted with each other in the Golgi. Silencing of ${\beta}^{\prime}-$, ${\gamma}-$, and ${\delta}$-COP by VIGS resulted in growth arrest and acute plant death in Nicotiana benthamiana, with the affected leaf cells exhibiting morphological markers of programmed cell death. Depletion of the COPI subunits resulted in disruption of the Golgi structure and accumulation of autolysosome-like structures in earlier stages of gene silencing. In tobacco BY-2 cells, DEX-inducible RNAi of ${\beta}^{\prime}$-COP caused aberrant cell plate formation during cytokinesis. Collectively, these results suggest that COPI vesicles are essential to plant growth and survival by maintaining the Golgi apparatus and modulating cell plate formation.

• 한국염색가공학회:학술대회논문집
• /
• 한국염색가공학회 2005년도 춘계학술발표회 논문집
• /
• pp.213-215
• /
• 2005

The metal complexes can be influenced not only by the central metal atoms and the substituent groups, but also by the native of the chelating atoms. For example, near-infrared absorbing chromophores were synthesized by the reaction of phenylenediamine derivatives with a solution of pottassium hydroxide followed by the addition of nickel(II) chloride. These dyes provide absorbing infrared light over 780-840 nm with an extinction coefficient of $2.5-6.0{\times}10^4$. By introduction of alkyl, alkoxyl, cyano, and other functional group into the parent dye, these dyes greatly improved the solubility in organic solvent. New near-infrared absorbing donor-acceptor chromophores have been investigated by varying the electron donating and accepting strength of the two halves of the molecule. The cyanine chromophores permit the simplest way of obtaining systems that absorb well into the near-infrared region of the spectrum. Cyanine dyes possess high extinction coefficients that initially increase with Increasing chain length. These chromophores could be useful in near-infrared optical materials.

• Journal of Microbiology and Biotechnology
• /
• 제26권8호
• /
• pp.1428-1438
• /
• 2016

In the present work, Arthrobacter sp. 25, a lead-tolerant bacterium, was assayed to remove lead(II) from aqueous solution. The biosorption process was optimized by response surface methodology (RSM) based on the Box-Behnken design. The relationships between dependent and independent variables were quantitatively determined by second-order polynomial equation and 3D response surface plots. The biosorption mechanism was explored by characterization of the biosorbent before and after biosorption using atomic force microscopy (AFM), scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the maximum adsorption capacity of 9.6 mg/g was obtained at the initial lead ion concentration of 108.79 mg/l, pH value of 5.75, and biosorbent dosage of 9.9 g/l (fresh weight), which was close to the theoretically expected value of 9.88 mg/g. Arthrobacter sp. 25 is an ellipsoidal-shaped bacterium covered with extracellular polymeric substances. The biosorption mechanism involved physical adsorption and microprecipitation as well as ion exchange, and functional groups such as phosphoryl, hydroxyl, amino, amide, carbonyl, and phosphate groups played vital roles in adsorption. The results indicate that Arthrobacter sp. 25 may be potentially used as a biosorbent for low-concentration lead(II) removal from wastewater.