• Korean Journal of Biological Psychiatry
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• v.5 no.2
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• pp.219-226
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• 1998

Cytosine arabinoside(AraC) inhibits DNA synthesis and ${\beta}$-DNA polymerase, an enzyme involved in DNA repair. This, a potent antimitotic agent, is clinically used as an anticancer drug with side effect of severe neurotoxicity. Earlier reports suggested that inhibition of neuronal survival by AraC in sympathetic neuron may be due to the inhibition of a 2'-deoxycytidine-dependent process that is independent of DNA synthesis or repair and AraC induced a signal that is triggers a cascade of new mRNA and protein synthesis, leading to apoptotic cell death in cultured cerebellar granule cells. The present study would suggest whether caspase family(ICE/CED-3-like protease) involved in AraC-induced apoptosis pathway of PC12 cells. It was observed that treatment of PC12 cells with AraC led to decrease of viability by MTT assay and morphology changes, which did not suggest that AraC induced apoptosis in PC12 cells. The mRNA of caspase-1/caspase-3 were expressed in PC12 cells constitutively, and AraC did not activate caspase family. These results suggest that caspase-1/caspase-3 may not be required for AraC-induced cell death pathway in PC12 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.107-115
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• 1997

We studied the effects of bile acids on the induction ofapoptosis in HepG2 human hepatocellular carcinoma cells. Treatment with either ursodeoxycholic acid (UDCA) or lithocholic acid (LCA) resulted in a dose- and time-dependent decrease in cell viability assessed by MTT assay. Both UDCA and LCA also induced genomic DNA fragmentation, a hallmark of apoptosis, indicating that the mechanism by which these bile acids induce cell death was through apoptosis. Cycloheximide, a protein synthesis inhibitor, blocked the apoptosis induced by these bile acids, implying that new protein synthesis may be required for the apoptosis. Intracellular $Ca^{2+}$ release blockers (dantrolene and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester) inhibited decreased cell viability and DNA fragmentation induced by these bile acids. Treatment of HepG2 cells with calcium ionophore A23l87 induced DNA fragmentation. These results suggest that UDCA and LCA induce apoptosis in the HepG2 cells and that the activation of intracellular $Ca^{2+}$ signals may play an important role in the apoptosis induced by these bile acids.

• Journal of Life Science
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• v.19 no.3
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• pp.305-310
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• 2009

Plasmid pGKV21 contains a 229-nucleotide (nt) single-strand DNA initiation (ssi) signal. Using asymmetric PCR, we prepared a small single-stranded (ss) DNA fragment of the ssi signal and, using the 229-nt ssDNA fragment, determined the requirements of RNA polymerase for priming and DNA-protein interaction. The ssi fragment prepared was able to generate primer RNAs with almost the same efficiency as the $M13{\Delta}lac182/229$ phage DNA. However, the cssi (complementary strand of the ssi signal) fragment could not synthesize primer RNAs. This result suggests that the 229-nt ssi signal functions in a strand specific manner. Gel retardation and DNase I footprinting demonstrated that the synthesized ssi fragment could interact with both E. coli RNA polymerase and SSB protein to synthesize primer RNA. In Escherichia coli [pWVAp], an addition of rifampicin resulted in an accumulation of ssDNA, indicating that the host-encoded RNA polymerase is involved in the conversion of ssDNA to double-stranded plasmid DNA.

• Journal of Life Science
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• v.14 no.2
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• pp.325-330
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• 2004

The RAD3 gene of Saccharomyces cerevisiae is required for excision repair and is essential for cell viability. RAD3 encoded protein possesses a single stranded DNA-dependent ATPase and DNA and DNA-RNA helicase activities. To examine the extent of conservation of structure and function of RAD3 during eukaryotic evolution, the RAD3 homolog gene was isolated by screening of genomic DNA library. The isolated gene was designated as HRD3 (Homologue of RAD3 gene). The over-expressed HRD3 protein was estimated to be a 75 kDa in size which is in good agreement with the estimated by the nucleotide sequence of the cloned gene. Two-dimensional gel electrophoresis showed that a number of other protein spots dramatically disappeared when the HRD3 protein was overexpressed. The overexpressed RAD3 protein showed a toxicity in E. coli host, suggesting that this protein may be involved in the inhibition of protein synthesis and/or degradation of host protein. To determine which part of HRD3 gene contributes to the toxicity in E. coli, various fusion plasmids containing a partial sequence of HRD3 and lac'Z gene were constructed. These results suggest that the C-terminal domain of HRD3 protein may be important for both toxic effect in E. coli and for its role in DNA repair in S. pombe.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.99-104
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• 2012

The present study was performed to evaluate the relationship between the neurotoxicity of acrylamide and the differential gene expression pattern in mice. Both locomotor test and rota-rod test showed that the group treated with higher than 30 mg/kg/day of acrylamide caused impaired motor activity in mice. Based on cDNA microarray analysis of mouse brain, myelin basic protein gene, kinesin family member 5B gene, and fibroblast growth factor (FGF) 1 and its receptor genes were down-regulated by acrylamide. The genes are known to be essential for neurofilament synthesis, axonal transport, and neuroprotection, respectively. Interestingly, both FGF 1 and its receptor genes were down-regulated. Genes involved in nucleic acid binding such as AU RNA binding protein/enoyl-coA hydratase, translation initiation factor (TIF) 2 alpha kinase 4, activating transcription factor 2, and U2AF 1 related sequence 1 genes were down-regulated. More interesting finding was that genes of both catalytic and regulatory subunit of protein phosphatases which are important for signal transduction pathways were down-regulated. Here, we propose that acrylamide induces neurotoxicity by regulation of genes associated with neurofilament synthesis, axonal transport, neuro-protection, and signal transduction pathways.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.877-880
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• 2000

Cycloinulooligosaccharide fructanotransferase (CFTase) converts inulin into cyclooligosaccharides consisting of six to eight molecules $\beta$-($2\rightarrow1$)-linked cyclic D-fructofuranose through intramolecular transfructosylation. We have examined the regulation of CFTase synthesis in Bacillus macerans and Bacillus subtilis. Synthesis of the CFTase was induced by inulin and it was subject to carbon catabolite repression (CCR) by glucose in both microorganisms. The DNA sequence upstream of the promoter of the CFTase gene was not involved in the inulin induction and glucose repression of the CFTase gene expression in B. subtilis. This suggests that the DNA element(s) responsible for the inuline induction and glucose repression is located downstream of the promoter region. Unexpectedly, the CCR of the expression of CFTase gene was observed not to be dependent on CcpA protein in B. subtilis.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.25-33
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• 1991

Antiviral activities of papaverine and nucleoside analogs, 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG) and acyclovir, against human cytomegalovirus (HCMV) infection were compared in vitro. Papaverine and DHPG were effective in reducing infectious HCMV yields with $ED_{50}{\s}$ (effective dose 50: the concentraion at which 50% of virus yields was obtained) of approximately 1.02 and $0.45{\mu}{\M}$, respectively; while acyclovir was less effective with an $ED_{50}$ of about $10.4{\mu}{\M}$The relative cytotoxicity of these drugs was evaluated under the same conditions used to measure infectious HCMV yields. Papaverine and DHPG demonstrated little cellular toxicity as measured by their effect on the viability of confluent cells at concentrations in the range of those demonstrating potent inhibition of HCMV replication. Similarly, protein synthesis was largely unaffected by these drugs in stationary mock-infected cells as measured by the incorporation of isotopically labelled amino acids. In contrast, cellular DNA synthesis was invariably reduced in the presence of either drug. HCMV-specific DNA synthesis was also strongly inhibited by papaverine and DHPG.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.396-413
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• 1996

Current acceptable methods for promoting periodontal regeneration are based on removal of diseased soft tissue. root treatment, guided tissue regeneration, introduction of new graft materials and biological mediators. Insulin-like growth factor-I(IGF-I) and Platelet-derived growth factor-BB(PDGF-BB), the members of the polypeptuyde growth factor family have been reported as the biological mediators which regulate a variety cellular matrix biologic activities of wound healing process including the cell proliferation, migration and extracellular matrix synthesis.The purposes of this study is to evaluate the combination effects of IGF-I and PDGF-BB on the cellular activity of the periodontal ligament cells to act as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the first premolar tooth extracted for the orthodontic treatment and were cultured in DMEM containing 10% FBS at the $37^{\circ}C$, 5% CO2 incubator. Author measured the DNA synthetic activity, and total protein, collagen and noncollagenous protein synthetic activities according to the concentration of 10,100ng/ml IGF-I and1,10 ng/ml PDGF-BB in combination. The results were as follows: Significantly increased in the 1 ng/ml PDGF-BB alone compared to the 10 ng/ml PDGF-BB alone(P<0.01) and in the 1 ng/ml PDGF-BB and 10, 100ng/ml IGF-I in combination compared to the 1 ng/ml PDGF-BB alone(P<0.05, P<0.0l). The synthetic activity of the total protein and collagen is significantly increased like to the synthetic activity of the DNA(P<0.05). The synthetic activity of the noncollagenous protein is increased according to the concentration of IGF_I, but not statistically statistically significant(P>0.05). The percent of the collagen is significantly in the 1ng/ml PDGF-BB and 10ng/ml IGF-I in combination compared to the 1ng/ml PDGF-BB alone(P<0.05) and in the 10ng/ml IGF-I in combination compared to the 10ng/ml PDGF-BB alone(P<0.05). The synthetic activity of the DNA is In conclusions, the percent study shows that PDGF-BB and IGF-I in combination have a potentiality to enhance the DNA synthesis and the total protein and collagen synthesis of The periodontal ligament cells, especially it is more significant in the low concentration of PDGF-BB compared to the high one. Thus, the PDGF-BB and IGF-I in combination may have important roles in promotion of periodontal litgment healing, and consequently, may useful for clinical application in periodontal regenerative procedures.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.173-192
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• 1999

The purpose of this study was to evaluate the effects of bioactive glass and natural coral on the human periodontal ligament fibroblast(HPLF) behaviors during the regeneration process of peridontium. To determine the cellular events occuring in the presence of the particles of bioactive glass and natural coral, HPLF were isolated from healthy premolar teeth extracted for orthodontic treatment. Cells were cultured in ${\alpha}$MEM at 37$^{\circ}C$, 5% $CO_2$, 95% humidity incubator. Bioactive glass and natural coral were powdered, and each particles(<40${\mu}$m) were placed on the cultured cells at the concentration of 0.3mg/ml, and 1,0mg/ml for experimental group. In control group no particles were added. And each group was evaluated by examining the cell morphology under phase-contrast micrograph at 4 day and transmission electron micrograph(TEM) and scanning electron micrograph(SEM) at 14 day, alkaline phosphatase activity at 5 and 9 day, protain synthesis at 4 day, DNA synthesis at 1, 2, 3 and 4 day, cell proliferation at 1, 3, 5,7 and 9 day and the formation of bone nodule at 30 day after culturing all groups in mineralizing supplemented mediun, No significant changes in cell morphology by adding these two matirials were found under phase contrast microscopy and TEM. HPLF phagocytocized each particles suggesting that HPLF is involved in the process of resorbing each particles and that bioactive glass were more biocompatible than natural coral. The ALPase activity of bioactive glass 0.3 mg/ml was similar with control groups and all the rests of control groups were significantly low(P<0.01) indicating a transient dedifferentiation of HPLF in the presence of bioactive glass and natural coral particles. There were no significant differences of protein synthesis between all groups. The DNA synthesis in experimental groups were significantly lower than control groups at 1, 2 and 3 day (P<0.01) but became similar to control groups at 4 day. Between control groups, the DNA synthesis in bioactive glass O.3mglml group was significantly higher than other groups(P<0.01). Cell proliferation in natural coral 1.0mg/ml and bioactive glass 1.0mglml groups were significantly lower than control group at 3 day(P<0.05) and there were no differences at 5, 7, 9 day. There were more bone nodule formation in experimental groups than in control groups. In conclusion, these results indicated that bioactive glass and natural coral have some effects of a transient dedifferentiation on HPLF and regeneration of periodontal tissues, however any significant cytotoxic effect on HPLF by these two particles were not found.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.212-217
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• 1997

Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of ${\gamma}$-rays (0.01 Gy) 4 or 20 hrs prior to high dose ${\gamma}$-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose .gamma.-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-.betha.-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose ${\gamma}$-ray irradiation to high dose ${\gamma}$-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.