• Journal of Microbiology
• /
• 제34권1호
• /
• pp.30-36
• /
• 1996

We have exmained the re-establishment of HIMRE mediated silencing function on the transcriptional activity of yeast heast shock gene HSP82. To test whether the onset of SIR repression can occur in growing cells in the rpesence of a potent inhibitor of DNA replication, HMRa/HSP82 strains with SIR4- and SIR4S$^{+}$ genetic backgrounds were arrested in S phase by incubation of a culture in 200 mM hydroxyurea for 120 min. It was clear that following a 20 minute heat shock, silencing of the HMRa/HSP82 allele in cells pretreated with hydroxyurea does occur in a SIR4-dependen fashion, even though the kinetics of repression appears to be substantially delayed. We also have tested whether re- establishement of silencing at the HMR/hsp82 locus can occur in G1-arrested cells. Cell cycle arrest at G1 phase was achieved by treatment of early log a cell cultures with .alpha.-factor mating pheromone, which induces G1 arrest. The result suggests that passage through S phase (and therefore DNA replication) is nor required for re-establishing silencer-mediated repression at the HMNRa/HSP82 locus. Finally, to test whether de nono protein synthesis is required for re-establishment of silencer-mediated repression, cells were pretreated with cycloheximide (500 /.mu.g/ml) 120 min. It was apparent that inhibiting protein synthesis delays, but does not prevent, re-establishment of silencer-mediated repression. Altogether, these results indicate that re-establishment of silencer-mediated repression is not dependent on the DNA replication and has no requirement for protein synthesis.s.

• 대한기계학회논문집A
• /
• 제31권7호
• /
• pp.756-763
• /
• 2007

The majority of catastrophic wheel failures are caused by surface opening fatigue cracks either in the wheel tread or wheel flange areas. The inclined cracks at railway wheel tread are initiated and the cracks are caused by wheel damage-spatting after 60,000 km running. Because the failured railway wheel is reprofiled before regular wheel reprofiling, the maintenance cost for the railway wheel is increased. Therefore, it is necessary to analyze the mechanism for initiation of crack. In the present paper, the combined effect on railway wheels of a periodically varying contact pressure and an intermittent thermal braking loading is investigated. To analyze damage cause for railway wheels, the measurements for replication of wheel surface and the effect of braking application in field test are carried out. The result shows that the damages in railway wheel tread are due to combination of thermal loading and ratcheting.

• Biomolecules & Therapeutics
• /
• 제3권2호
• /
• pp.111-115
• /
• 1995

Natural products, total number of 175, were screened to test for their effect on the replication of human immunodeficiency virus type 1 (HIV-1). Five of them, such as Eriobotrya japonica, Eugenia caryphyllata, Cuscuta chinensis, Glycyrrhiza uralensis, and Coptis chinensis were shown to be effective in inhibiting the replication of HIV-1 in tissue culture and their selectivity indexes were 42, 40, 14, 18 and 65, respectively. To further fractionate Coptis chinensis, which is shown to be highest anti-HIV-1 activity, methanol extracts of Coptis chinensis were fractionated into methylene chloride at pH3, pH10 and water residue. The selectivity Indexes of CH$_2$C1$_2$(pH 3), CH$_2$C1$_2$(pH 10) and water residue were 50, 22 and 98 respectively. Our results show that the water residue of Coptis chinensis was the most effective for anti-HIV-1 activity.

• 미생물학회지
• /
• 제34권4호
• /
• pp.248-253
• /
• 1998

Esherichia coli(E. coli) K12 균주를 숙주세포로 삼는 박테리오파아지인 N4는 single-stranded DNA에 결합하는 단백질인 N4SSB(bacteriophage N4-coded single-stranded DNA-binding protein) 단백질을 만든다. N4SSB 단백질은 N4 DNA replication 뿐만 아니라 late transcription과 N4 DNA recombination에도 필요한 여러 가지 기능을 가진 단백질이다. N4 late transcription은 숙주세포인 E. coli의 $E{\sigma}^{70}$ RNA polymerase에 의해서 수행이 되나 N4SSB 단백질을 반드시 필요로 하기 때문에 N4SSB 단백질이 생성될 때까지는 N4 late promoter로부터 RNA 합성이 일어나지 않는다. 본 연구에서는 N4SSB의 N4 DNA replication과 late transcription, 그리고 N4 DNA recombination에 필요한 영역(domain)을 알아내기 위해서 여러 가지 돌연변이형 N4SSB 단백질을 만들어 N4 DNA replication과 late transcription, 그리고 N4 DNA recombination의 3가지 작용에 대한 in vivo 활성을 조사 분석하였다. 그 결과 N4SSB 단백질의 C-말단기에 있는 7개의 아미노산이 N4SSB 단백질의 활성에 중요하다는 것을 알 수 있었다. 특히 C-말단기의 7개의 아미노산에는 세 개의 lysine이 포함되어 있는데 이 lysine이 N4SSB 단백질의 활성에 중요한 역할을 한다는 것이 제시되었다.

• 대한의생명과학회지
• /
• 제23권4호
• /
• pp.372-379
• /
• 2017

This study was investigated to test whether paternal DNA that was destined for degradation was properly licensed by testing for the presence of mini-chromosome maintenance protein (MCM) 7 and origin recognition complex (ORC) 2 in the paternal pronuclei. ORC2 is one of the first licensing protein to come on and MCM7 is one of the last licensing protein to come on. Zygotes were prepared by injection of control and treated sperm injection (ICSI). To control for DNA breakage, epididymal spermatozoa were treated with DNase I to fragment the DNA, then injected into oocytes. The presence of MCM7 and ORC2 in the pronuclei of mouse zygotes was tested by immunohistochemistry, just before the onset of DNA synthesis, at 5 h after fertilization, and after DNA synthesis began, at 9 h post fertilization. We found that in all cases, both MCM7 and ORC2 were present in both pronuclei at 5 h after sperm injection, just before DNA synthesis began. This indicates that no matter how extensive the DNA damage, recruitment of licensing proteins to the origins of replication was not inhibited. Sperm DNA fragmentation does not prevent licensing of DNA replication origins. Furthermore, the embryo recognizes DNA that is damaged by nucleases. Our data indicate that the one-cell embryo does harbor a mechanism to prevent the replication of severely damaged DNA from spermatozoa, even though the embryos do not undergo classical apoptosis.

• 문화기술의 융합
• /
• 제10권1호
• /
• pp.411-417
• /
• 2024

재해 발생 시 주요 IT 인프라 중단을 최소화하고 연속적인 비즈니스 서비스를 제공하기 위한 재해복구 계획 및 재해복구시스템의 구축은 반드시 필요하다. 재해복구시스템 구축과정에서 데이터 복제는 재해 발생 시 중단 없는 연속적인 비즈니스 서비스 제공을 위한 데이터 복구의 핵심요소로 데이터 복제방식은 시스템 구성환경과 재해복구 목표수준에 따라 결정할 수 있다. 본 논문에서는 재해복구시스템 구축에서 구성환경과 재해복구 목표수준에 적합한 데이터 복제방식 결정 방안에 대해 제시한다. 또한 복제방식 결정 절차를 적용하여 재해복구시스템을 구축하고 구축 결과를 분석한다. 재해복구시스템 구축 후 재해 상황에서 재해복구센터로 서비스가 전환, 정상적인 서비스가 진행되는지를 판단하기 위한 모의 테스트를 진행하고 결과를 분석하였다. 그 결과 재해복구시스템 구축 단계에서는 체계적으로 최적의 데이터 복제방식의 선정이 가능했다. 구축된 재해복구시스템은 연속적인 비즈니스 서비스 제공을 위해 재해복구센터로 서비스 전환되는 시간 RTO는 3.7시간으로, Tier 2였던 재해복구 수준이 목표수준 RTO 4시간 이내, RPO=0으로 개선되었다.

• 생약학회지
• /
• 제30권3호
• /
• pp.238-243
• /
• 1999

This study was undertaken to test for anti-hepatitis B virus (HBV) activity of the aqueous extracts prepared from 9 medicinal plants of Korea (Cornus officinalis, Caesalpinia sappan, Rubus coreanus, Lycium chinense, Artemisia capillaris, Isatis tinctoria, Phyllanthus urinaria, Lysimachia christinae, Lonicera japonica). Aqueous extracts were tested for cytotoxicity and assayed for inhibition of HBV replication by measurement of HBV DNA and surface antigen (HBsAg) levels in the extracellular medium f HepG2 2.2.15 cells. The extract from Rubus coreanus, Artemisia capillaris, Phyllanthus urinaria decreased the levels of extracellular HBV virion DNA at concentrations ranging from 128 to $256\;{\mu}g/ml$ and inhibited the production fo HBsAg dose-dependently without showing cytotoxicity. Our findings suggest that these three hebal medicinal plants may have potential to develop as specific anti-HBV drugs in the future.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1465-1466
• /
• 2010

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 1995년도 추계학술대회발표논문집; 서울대학교, 서울; 30 Sep. 1995
• /
• pp.45-45
• /
• 1995

• Biomolecules & Therapeutics
• /
• 제7권2호
• /
• pp.133-137
• /
• 1999

This study was undertaken to test for anti-Hepatitis B virus (HBV) activity of the aqueous extracts prepared from Eugenia caryophyllate, Ephedra sinica, Cinnamomum cassia. Aqueous extracts were assayed for the inhibition of HBV replication by measurement of HBV DNA and surface antigen (HBsAg) levels in the extracellular medium of HePG2 2.2.15 cells. All extracts decreased the levels of extracellular HBV virion DNA at concentrations ranging from 128 to 256 $\mu$g/ml and inhibited the production of HBsAg dose-dependently. Our findings suggest that these three hebal medicinal plants may have potential to develop as specific anti-HBV drugs in the future.