• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1618-1622
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• 2006

Bacteriophage T7 gp4A' is a ring-shaped hexameric DNA helicase that catalyzes duplex DNA unwinding using dTTP hydrolysis as an energy source. To investigate the effect of single-stranded DNA (ssDNA) on the kinetic pathway of dTTP hydrolysis by the T7 DNA helicase complexed with ssDNA, we have first determined optimal concentration of long circular M13 single-stranded DNA and pre-incubation time in the absence of $Mg^{2+}$ which is necessary for the helicase-ssDNA complex formation. Steady state dTTP hydrolysis in the absence of $Mg^{2+}$ by the helicase-ssDNA complex provided $k_{cat}$ of $8.5\;{\times}\;10^{-3}\;sec^{-1}$. Pre-steady state kinetics of the dTTP hydrolysis by the pre-assembled hexameric helicase was monitored by using the rapid chemical quench-flow technique both in the presence and absence of M13 ssDNA. Pre-steady state dTTP hydrolysis showed distinct burst kinetics in both cases, indicating that product release step is slower than dTTP hydrolysis step. Pre-steady state burst rates were similar both in the presence and absence of ssDNA, while steady state dTTP hydrolysis rate in the presence of ssDNA was much faster than in the absence of ssDNA. These results suggest that single-stranded DNA stimulates dTTP hydrolysis reaction by T7 helicase by enhancing the rate of product release step.

• The Plant Pathology Journal
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• 제27권4호
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• pp.315-323
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• 2011

Soybean plants infected with Bean pod mottle virus (BPMV) develop acute symptoms that usually decrease in severity over time. In other plant-virus interactions, this type of symptom recovery has been associated with degradation of viral RNAs by RNA silencing, which is accompanied by the accumulation of virus-derived small interfering RNAs (siRNAs). In this study, changes in the accumulation of BPMV siRNAs were investigated in soybean plants infected with BPMV alone, or infected with both BPMV and Soybean mosaic virus (SMV) and in transgenic soybean plants expressing SMV helper component-protease (HC-Pro). In many potyviruses, HC-Pro is a potent suppressor of RNA silencing. In plants infected with BPMV alone, accumulation of siRNAs was positively correlated with symptom severity and accumulation of BPMV genomic RNAs. Plants infected with both BPMV and SMV and BPMV-infected transgenic soybean plants expressing SMV HC-Pro exhibited severe symptoms characteristic of BPMVSMV synergism, and showed enhanced accumulation of BPMV RNAs and siRNAs compared to plants infected with BPMV alone and nontransgenic plants. Likewise, SMV HC-Pro enhanced the accumulation of siRNAs produced from a silenced green fluorescent protein gene in transient expression assays, while the P19 silencing suppressor of Tomato bushy stunt virus did not. Consistent with the modes of action of HC-Pro in other systems, which have shown that HC-Pro suppresses RNA silencing by preventing the unwinding of duplex siRNAs and inhibiting siRNA methylation, these studies showed that SMV HC-Pro interfered with the activities of RNA-induced silencing complexes, but not the activities of Dicer-like enzymes in antiviral defenses.

• 펄프종이기술
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• 제40권2호
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• pp.37-42
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• 2008

Defects of corrugated board were limiting factors to the corrugated industry's growth. On-line detecting systems of defects are beneficial to increase profits of the corrugated board companies by reducing base paper consumption, increasing process reliability, and increasing productivity. By replacing naked eye inspection of defects to a defects detecting system, continuous inspection without fatigue may guarantee final products quality. The system was developed, which was consisted of line scan CCD camera, lens, illuminating parts, high speed image processor, software, various input parts, and output parts. First installation location of the system was at before fluting process after base paper unwinding, and surface of liner board was inspected by the system. Second installation location was after fluting process and combining process for liner board. Production loss includes ragged appearance of edge, irregular flute shape, wrong combination of flute, score cracking, defects in base paper, and flute cracking. The production loss was analyzed before and after the system installation at a commercial domestic mill. The production loss ratio was defined as a production loss weight per total production weight. The production loss ratio before the installation was decreased a lot from 1.28%(during 3 months before installation) to 0.76%(during 12 months after the first installation) and to 0.25%(during 6 months after the second installation).

• 생명과학회지
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• 제15권6호
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• pp.935-940
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• 2005

Coumarine이 부착된 인산결합 단백질 (PBP-MDCC)의 형광변화가 뉴클레오사이드 삼인산 가수분해과정에서 배출된 무기 인산의 양을 측정하기 위해 관찰되었다. PBP-MDCC 정제후, 형광 방출 스펙트럼은 형광세기가 PBP-MDCC의 몰비을로 약 $70\%$까지 직선형태로 증가하는 것을 보였다. 형광 신호와 인산 기준물질과의 상호관계 측정이 인산 농도-형광세기 표준곡선을 구하기 위하여 stopped-flow 기구에서 행하여졌다. dTTP 가수분해로 부터 나오는 에너지를 이용하여 이중나선 DNA를 풀어주는 단백질인 T7박테리오파지 나선효소를 dPTT라 반응 시켰을 때, 형광변화를 배출된 인산의 양으로 전환할 수 있었다. 인산 배출 결과는 단일가닥 Ml3 DNA가 T7나선 효소에 의한 dTTP가수분해반응을 여러배 증가시키는 것을 보인다. 뉴클레오타이드 삼인산 가수분해 반응에 있어서 종말점 분석 대신에, PBP-MDCC에 의한 연속적인 인산 배출 분석이 배출된 인산을 측정하는데 있어서 쉽고 편리한 방법임을 보였다.

• 한국식생활문화학회지
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• 제8권3호
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• pp.275-287
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• 1993

An ecological survey of food and nutrition was conducted in April and May, among 278 children, 6 to 12 years old, of the Youido elementary school, which offers no school lunch program, and is situated in Youido delta of Han River side of Seoul, known as the location of one of the socioeconomically high groups; Eighteen percent and 18.3% of subjects were proven to be overweight and obese, respectively. With regard to frequency of skipping breakfast, 28.4% of the subjects skipped breakfast often and 2.5% of subjects skipped breakfast every morning. Obese children showed good appetite and the time consumed for eating was shorter than those of normal or overweight children. Most serious anxiety among the mothers for those children was food habit of `eating rapidly' and `overeating'. Another striking observation was that 14.4% of the subjects ate only one side-dish with boiled rice, and such a pattern was more often found in the normal or slim group. Most of the subjects had their snacks after being back in home from school. Thirty-one percent of the children had snacks when they felt hungry, 69% had snacks for various reasons such as `habitually', `for unwinding', and `mother gives me snacks'. Thirty-eight percent of the boys and 19% of the girls had physical exercise everyday and overweight and obese children got exercise more frequently. But the time consumed for exercise was much more shorter than that of normal subjects. Most of the children liked fruits, meats, and biscuit, in contrast, lowest preferency was for vegetables, fermented fish products, and boiled rice mixed with other grains. Obese children experienced more kinds of food than normal or slim group. The study found that habits of overeating due to good appetite and eating rapidly were recognized as one of dominant reasons causing obesity among children. On the other hand, serious dietary problem of children of normal or slim group was eating less variety of food. Active nutrition education for both children and mothers will be recommended with joint participation of teachers.

• 한국산학기술학회논문지
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• 제13권6호
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• pp.2458-2464
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• 2012

최근 디스플레이용 부품소재는 국가 산업 경쟁력을 강화시킬 수 있는 고부가가치 산업분야로 발전하고 있다. 하지만 디스플레이용 부품소재 생산을 위한 시스템은 대부분 수입에 의존하며 개발이 미비한 상태이다. 그러므로 디스플레이용 부품소재인 스페이서 테이프 생산을 위한 엠보싱 처리 시스템의 국산화 및 생산성 증대를 위한 시스템 향상이 시급한 실정이다. 따라서 본 논문에서는 엠보싱처리 시스템의 국산화 및 생산성 증대를 위한 스페이서 테이프 생산을 위한 회전형 엠보싱 처리 시스템을 제안한다. 시스템은 권출부, 성형부, 권치부, 세정부, 검사부로 구성된다. 이 중, 성형부의 금형을 회전형 방식으로 설계하였고, 각 구성품들을 설계하고 시제작품을 제작하여 성능 실험을 하였다. 성능 실험은 삼차원 측정기를 통해 엠보싱 형상, 직경, 엠보싱 간격 및 반대편 엠보싱과의 거리를 측정하였다. 오염물 검출 실험을 하기 위해, 검사부를 통해 첫 번째 샘플과 반복 생산한 후의 샘플에 대해 이물질 레벨을 측정하였다. 그리고 샘플에 이물질을 부착한 후 세정부를 통해 샘플을 세정한 후의 이물질 개수를 측정하여 오염물 세정 실험을 하였다. 또한, 시제작품에 의해 생산되는 스페이서 테이프의 생산성을 측정하였다.