• Title, Summary, Keyword: DNA synthesis

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Gamma-ray Induced DNA Repair Synthesis in Relation to Chromosome Exchanges in Mammalian Cells in Vitro (哺乳動物細胞에 있어 감마線에 의한 DNA 回復合成과 染色體交換과의 聯關性)

  • Park, Sang-Dai
    • The Korean Journal of Zoology
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    • v.18 no.1
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    • pp.41-49
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    • 1975
  • Dose response and time dependence of DNA repair synthesis were investigated to determine the possible relationship between DNA repair synthesis and chromosome exchanges in $\\gamma$-ray irradiated BHK-21 and KB cell lines. DNA repair synthesis induced by $\\gamma$-ray was dose dependent up to 5kR, then leveling off occurred until 50 kR was reached. Time dependence of DNA repair synthesis was continued for up to 1$\\sim$2 hours after irradiation although the initial dose responses were cell line specific. Chromosome exchanges induced by $\\gamma$-ray showed different radiosensitivities in these cell lines and did not show a correlation with the DNA repair synthesis.

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DNA Repair Synthesis Induced by Bleomycin in HeLa $S_3$ Cells Pretreated with Base Analogs (鹽基相似體를 前處理한 HeLa $S_3$ 細胞에 있어 Bleomycin에 의한 DNA 回復合成)

  • Um, Kyung-Il;Park, Sang-Dai
    • The Korean Journal of Zoology
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    • v.20 no.1
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    • pp.41-48
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    • 1977
  • Dose response of DNA repair synthesis induced by bleomycin was dose-dependent in lower doses, and maximum rate of it at 5 $\\mu$g/ml represents about 15% of total cells analyzed. At higher doses DNA-repair synthesis was reduced and the rate of it remained unchanged even prolonged treatment. Pretreatment with BUdR or IUdR was found to enhance DNA repair synthesis and also to interfere with semiconservative DNA synthesis at higher doses. Time dependence study showed that DNA repair synthesis occurred as long as for 24 hours after removal of bleomycin. These results seem to suggest that bleomycin is not to be an effective chemical in inducing excision repair and that damages induced in DNA by this drug might include not only strand breaks but other types of DNA damage.

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Effects of Polyamines on DNA Synthesis in Nicotiana tabacum L. Suspension Cultured Cells (담배(Nicotiana tabacum L.) 현탁배양 세포에서 DNA 합성에 미치는 Polyamine의 효과)

  • 남경희
    • Journal of Plant Biology
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    • v.36 no.1
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    • pp.19-27
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    • 1993
  • Effects of polyamines on DNA synthesis were studied in synchronized culture of Nicotiana tabacum L. When DFMO and DFMA, inhibitors of ornithine decarboxylase and arginine decarboxylase, respectively were initially applied to the cells, the polyamine contents were rapidly dropped and [methyl-3H] thymidine incorporation into DNA was markedly reduced during the early stage of culture period. Inhibition of DNA synthesis, however, was partially reversed when these inhibitors were applied simultaneously with putrescine. In addition, exogenous administration of putrescine also increased the DNA synthesis during the all over the culture period. In vitro activity of DNA polymerase from Nicotiana tabacum L. was promoted by increasing concentrations of polyamines in the reaction mixture. Maximal activity was shown at 5 mM putrscine, 0.5 mM spermidine and spermine, respectively. Lack of Mg2+ ion in the reaction buffer resulted in an inhibition of the enzyme activity by about 30%. The inhibition could not be completely reversed by application of polyamines at optimal concentrations. These results suggest that polyamines promote the DNA synthesis in vivo and in vitro by stabilizing the DNA-helix upon binding to negatively charged groups on DNA or increasing the activity of DNA polymerase in Nicotiana tabacum L.

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Sensitization Effects of Thymidine Analogs on Methyl Methanesulfonate Induced DNA Repair synthesis (Methyl Methanesulfonate 에 의한 DNA 回復合成에 미치는 Thymidine 相似체體의 感受性 효과)

  • Park, Sang-Dai;Um, Kyung-Il
    • The Korean Journal of Zoology
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    • v.18 no.3
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    • pp.131-140
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    • 1975
  • Dose response for the nuscheduled DNA synthesis induced by various concentration of MMS was dose dependent and directly proportional to dose increased. Time dependence of unscheduled DNA synthesis was continued up to 4 hours, with the peak appearing 2$\\sim$3 hours after treatment with MMS and $^3 H$-thymidine labeling. Single treatment with BUdR or IUdR does not induce unscheduled DNA synthesis. BUdR and IUdR greatly enhanced MMS-induced unscheduled DNA synthesis, but the dose responses were different from that of single treatment with MMS. IUdR was found to be more effective sensitizer on MMS-induced unscheduled DNA synthesis.

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Environmental Toxic Agents on Genetic Material and Cellular Ativity V. The Roles of DNA Polymerases on Mutagen-Induced DNA Repair Synthesis in Relation to Cell Cycle in Chinese Hamster Ovary Cells (환경성 유해요인이 유전물질과 세포활성에 미치는 영향 V. CHO세포에서 세포주기에 따라 돌연변이원에 의해 유발된 DNA회복합성에 미치는 DNA중합효소의 역할)

  • 엄경일;김춘광;신은주;문용석;이천복
    • Environmental Mutagens and Carcinogens
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    • v.9 no.1
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    • pp.23-32
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    • 1989
  • Chinese hamster ovary (CHO)-K1 cells echibited a differential sensitivity in the process of DNA repair synthesis induced by ethyl methanesulfonate (EMS) or bleomycin (BLM) in relation to cell cycle. Two assays were employed in this study: alkaline elution and unscheduled DNA synthesis. The post-treat-ment with aphidicolin (APC), an inhibitor of DNA polymerase alpha, inhibited DNA repair synthesis induced by EMS in G2 phase, while APC did not show any effect on BLM-induced DNA repair synthesis in all phases. On the other hands, the 2', 3'-dideoxythymidine (ddTTP), an inhibitor of DNA polymerase beta, inhibited DNA repair synthesis induced by EMS or BLM in both of G1 and G2 phases. These results suggested that the involvement of DNA polymerase alpha and beta in DNA repair was dependent on cell stage or used chemical agent.

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Effects of Sipyukmiyukieum on DNA Synthesis, cAMP Synthesis and MHC-class II Expression of FRTL-5 Thyroid Cells (십육미류기음(十六味流氣飮)이 FRTL-5 갑상선 세포의 DNA와 cAMP의 합성 및 MHC-class II의 발현에 미치는 영향)

  • Kim, Byoung-Woo;Yi, Jae-Eun
    • The Journal of Internal Korean Medicine
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    • v.26 no.2
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    • pp.398-408
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    • 2005
  • Objective: Graves' disease encompasses hyperthyroidism and diffused goiter associated with auto-antibodies to the thyroid stimulating hormone(TSH) receptors. In clinical environment, treatments of Graves' disease have many side effects such as recurrence and hypothyroidism. We've studied the effects of Sipyukmiyukieum on DNA synthesis, cAMP synthesis, and MHC-class II expression of FRTL-5 thyroid cells were studied. Methods: DNA synthesis was investigated by using BrdU staining and cAMP synthesis by ELISA kit, and expression of $interferon-{\gamma}$ activated MHC class II by Flow cytometer. Results: After introduction of Sipyukmiyukieum, significant inhibition of DNA synthesis. cAMP synthesis, and expression of $interferon-{\gamma}$ activated MHC class II of FRTL-5 thyroid cells was observed. Conclusions: Judging from these results, Sipyukmiyukieum has potential as a potent herbal treatment for inhibiting the enlargement of goiter, synthesis of abnormal thyroidal hormones, and autoimmuine responses of Graves' disease.

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Circadian DNA-synthetic Rhythm Accompanied Mitotic Rhythm in Newly Hatched in Chicken Liver : Possible Role of Feeding Regiment (사료섭취가 병아리의 간세포증식 리듬에 미치는 영향)

  • Han, Joon-Pyo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.4
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    • pp.444-448
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    • 1989
  • The division and circadian DNA-synthesis rtythm are studied in chick liver immediately after hatching. The vision function is tested by the mitotic and the $^3H-thymidine$ labelling index The DNA synthesis exhibited a cyclic variation of 12 hours immediately after hatching. The rhythmic changes of DNA synthesis was maintained in the liver of meal-fed chickens, but the DNA synthetic activities decreased gradually in the starved chicken liver. From this time, the rhythm of DNA synthesis was greatly afffected by lighting schedule, all these DNA synthesis of chicken liver was accompained by mitosis.

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Effects of Ginseng Saponin on DNA Strand Breaks and Replication Inhibition by Benzo(a)Pyrene in CHO-Kl Cells (Benzo(a)Pyrene 유발 DNA 상해 및 복제 억제에 미치는 인삼사포닌의 영향)

  • Park, Jin-Kyu;Park, Ki-Hyun
    • Journal of Ginseng Research
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    • v.16 no.3
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    • pp.210-216
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    • 1992
  • The effect of saponin extracted from Panax grneng CA Meyer on DNA repair and replicative DNA synthesis were examined in CHO-Kl cells cotreated with benzo(a)pyrene and rat liver S-15 fraction. The DNA strand breaks inititated by benzo(a)pyrene metabolites were measured by alkaline election technique. The addition of ginseng saponin to the culture media resulted in decrease of benzo(a)pyrene-induced DNA strand breaks, and restored the suppressed-semiconservative-DNA-synthesis by the carcinogen. DNA repair synthesis in the damaged cells was also elevated by the ginseng treatment when the repairing activites were measured for the (3H)-thymidine incorporation into the carcinogen damaged cellular DNk Comparative analysis of DNA-adduces of benzo(a)pyrene metabortes in microsomes suggested that ginseng saponin treatment in rats reduced the formation of electrophilic metabolites of benzo (a)-pyrene in the rat liver microsomes.

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Effect of 3-Aminobenzamide on DNA Repair Synthesis and Chromosome Aberrations Induced by Mutagens in Synchronized Mammalian Cells (동시화된 포유동물세포에서 돌연변이원에 의해 유발된 DNA 회복합성 및 염색체이상에 미치는 3-Aminobenzamide의 영향)

  • 신은주;강인영;엄경일
    • Environmental Mutagens and Carcinogens
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    • v.11 no.2
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    • pp.107-117
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    • 1991
  • The effect of 3-aminobenzamide (3AB), an inhibitor of poly (ADP-ribose) polymerase, on ethyl methanesulfonate (EMS)-or bleomycin (BLM)-induced DNA repair synthesis and chromosome aberrations was examined during the cell cycle of Chinese hamster ovary (CHO)-K$_1$ cells. The synchronized cells were obtained by using thymidine double block method and mitotic selection method. Three assays were employed in this study: unscheduled DNA synthesis, alkaline elution and chromosome aberrations. 3AB alone did not induce DNA repair and chromosome aberrations in all phases. The post-treatment with 3AB inhibited DNA repair synthesis induced by EMS or BLM in G$_2$ phase, whereas 3AB did not affect chromosome aberrations induced by EMS or BLM in all phases. These results suggest that 3AB aggravates the cell cycle disturbance which occur after DNA damage, and leads to an accumulation of cells at G$_2$ phase, and inhibits DNA repair synthesis, while the effect 3AB on chromosome aberrations may need reevaluated.

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