• 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.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• 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.

• Korean Journal of Microbiology
• /
• 제34권4호
• /
• pp.248-253
• /
• 1998

Bacteriophage N4, a lytic phage specific for Esherichia coli K12 strain encodes single-stranded DNA-binding protein, N4SSB (bacteriophage N4-coded single-stranded DNA-binding protein). N4SSB protein is originally identified as a protein required for N4 DNA replication. N4SSB protein is also required for N4 late transcription, which is catalyzed by E. coli ${\sigma}^{70}$ RNA polymerase. N4 late transcription does not occur until N4SSB protein is synthesized. Recently it is reported that N4SSB protein is essential for N4 DNA recombination. Therefore N 4SSB protein is a multifunctional protein required for N4 DNA replication, late transcription, and N4 DNA recombination. In this study, a variety of mutant N4SSB proteins containing internal deletions or substitutions were constructed to define and characterize domains important for N4 DNA replication, late transcription, and N4 DNA recombination. Test for the ill vivo activity of these mutant N4SSBs for N4 DNA replication, late transcription, and N4 DNA recombination was examined. The results suggest that C-terminal 7 amino acid residues are important for the activity of N4SSB. Three lysine residues, which are contained in this region play important roles on N4SSB activity.

• Biomedical Science Letters
• /
• 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.

• The Journal of the Convergence on Culture Technology
• /
• 제10권1호
• /
• pp.411-417
• /
• 2024

In the event of a disaster, it is essential to establish a disaster recovery plan and disaster recovery system to minimize disruption to major IT infrastructure and provide continuous business services. In the process of building a disaster recovery system, data replication is a key element of data recovery to provide uninterrupted and continuous business services in the event of a disaster. The data replication method can be determined depending on the system configuration environment and disaster recovery goal level. In this paper, we present a method for determining a data replication method suitable for the configuration environment and disaster recovery target level when building a disaster recovery system. In addition, the replication method decision procedure is applied to build a disaster recovery system and analyze the construction results. After establishing the disaster recovery system, a test was conducted to determine whether the service was transferred to the disaster recovery center in a disaster situation and normal service was provided, and the results were analyzed. As a result, it was possible to systematically select the optimal data replication method during the disaster recovery system construction phase. The established disaster recovery system has an RTO of 3.7 hours for service conversion to the disaster recovery center to provide continuous business services, and the disaster recovery level, which was Tier 2, has been improved to the target level within 4 hours of RTO and RPO=0.

• Korean Journal of Pharmacognosy
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1465-1466
• /
• 2010

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 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.