• 대한약리학회지
• /
• 제28권2호
• /
• pp.213-222
• /
• 1992

Benzopyrene (BP), 7,12-dimehyl benzanthracene (DMBA), nitrosomethyl urea (NUMU) 및 nicotine과 같은 발암성 화학물질들이 바이러스 감염된 vero 세포의 단층 세포 배양에서 I형 단순성포진 바이러스 (HSV-1)의 복제, 세포융해, DNA합성 및 단백질 합성에 미치는 효과를 관찰하였다. 1. BP와 DMBA는 HSV-1의 복제와 세포융해작용을 유의성있게 억제하였으나 nicotine과 NMU는 별로 억제하지 않았다. 2. 모든 발암성 화학물질은 바이러스의 DNA합성을 억제하지 못하였지만 새로 합성되는 후손바이러스 DNA로 부터 표현되는 gamma 단백질의 표현은 BP와 DMBA에 의해서 현저하게 억제되었다. 그러나 모든 발암성 화학물질은 바이러스의 alpha 및 beta 단백질의 합성은 억제하지 못하였다. 이상의 결과로 보아 발암성화학물질이 존재하고 있는 배지내에서 새로 합성되는 바이러스의 DNA로 부터 표현되는 gamma 단백질의 결함이 있음을 알 수가 있었으며 이같은 개념은 발암화학물질의 존재하에서 바이러스의 DNA와 단백질이 거의 정상적으로 합성됨에도 불구하고 바이러스의 복제가 일어나지 않는다는 사실이 뒷받침해주고 있다.

• BMB Reports
• /
• 제43권11호
• /
• pp.732-737
• /
• 2010

RNA interference is a post-transcriptional silencing mechanism triggered by the bioavailability and/or exogenous introduction of double-stranded RNA (dsRNA) into cells. Here we describe a novel method for the synthesis of siRNA in a single vessel. The method employs in vitro transcription and a single-stranded DNA (ssDNA) template and design, which incorporates upon self-annealing, two promoters, two templates, and three loop regions. Using this method of synthesis we generated efficacious siRNAs designed to silence both exogenous and endogenous genes in mammalian cells. Due to its unique design the single-stranded template is easily amenable to adaptation for attachment to surface platforms for synthesis of siRNAs. A siRNA synthesis platform was generated using a 3' end-biotinylated ssDNA template tethered to a streptavidin coated surface that generates stable siRNAs under multiple cycles of production. Together these data demonstrate a unique and robust method for scalable siRNA synthesis with potential application in RNAi-based array systems.

• 대한치과교정학회지
• /
• 제24권4호
• /
• pp.933-943
• /
• 1994

The present study was undertaken to determine the effect of tensile force on DNA and protein biosynthesis in bone cells, and to identify the cell type(s) which primarily respond to external physical force among the heterogenous bone cell populations. As a prerequisite for this study, two bone cell populations which retain fibroblastic and osteoblastic feature were isolated from fetal rat calvaria with sequential enzyme digestion scheme. Tensile force was delivered to each bone cell population by two acrylic resin plates connected with a orthodontic expansion screw during culture period. Rate of DNA and protein synthesis in each bone cell population were assessed by the incorporated radioactivity of $[^3H]-thymidine$ into DNA and $[^3H]-proline$ into fraction of collagenase-digestible protein and noncollagenous protein, respectively. DNA synthesis of osteoblast-like calvarial cell populations was increased significantly by the application of tensile force for 24 hours. In contrast, no alteration in DNA synthesis of fibroblast-like populations could be observed in response to applied force. Tensile force induced the change in protein synthesis of bone cell populations with the same pattern. Total protein and collagen synthesis were increased whithin 24 hours in osteoblast-like populations, but not in fibroblast-like populations by tensile force application. These findings indicate that physical force can affect cellullar activity of the particular cell population, not all cell Populations residing in bone and osteoblasts respond more sensitively than fibroblasts. So osteoblasts can modulate the behavior of other bone cells including osteoclasts by producing several local regulating factors of bone metabolism. In this context, preferential responsiveness of osteoblasts to applied tensile force observed in this study suggests that osteoblasts may play an important role in regulation of physical force-induced remodelling process.

• Restorative Dentistry and Endodontics
• /
• 제20권1호
• /
• pp.71-95
• /
• 1995

Bacteria have been regarded as a one of major etiologic factors in root canal infections. In endodontic treatment the effective removal of pathogenic microorganisms in the root canal is the key to successful outcome. Bacterial cell wall components may play an important role in the development of pulpal and periapical disease. The purpose of this study was to evaluate the effect of sonic extracts of Streptococcus spp. on cultured L929 cells and to characterize cell wall protein profiles of Streptococcus spp. Streptococcus spp. were isolated from infected root canals and identified with Vitek Systems(Biomeriux, USA). Five streptococci, namely S. sanguis, S. mitis, S uberis, S. mutans (ATCC 10449) and S. faecalis (ATCC 19433) weere enriched in brain heart infusion broth. Cell pellets were sonicated and cell wall extracts were dialyzed and membrane filtered. Prepared cell wall proteins were applied to cultured L929 cell. The cell reaction were evaluated by monitoring DNA synthesis, cell numbers and the change of cell morphology. The total cell wall protein profiles of microorganisms were characterized by sodium dodecyl sulfate polyacrylamide-gel eledruphoresis(SDS-PAGE). DNA synthesis of L929 cells were reduced by the increasing concentration of sonic extracts. DNA synthesis was significantly suppressed in more than $50{\mu}g$/ml of sonic extract conentration in five streptococci. S. nutans (ATCC 10449) showed stronger suppression on DNA synthesis than remaining four streptococci, which had the similar effect on DNA synthesis. Analysis of DNA synthesis measured by [$^3H$]-thymidine uptake was more sensitvie method than cell counting. Sonic extracts affected the microscopic findings of L929 cells. The protein profiles indicated that all five strains shared two major proteins with molecular masses of 70.8 and 57.5 kD respectively. S. uberis and S. mutans shared common minor proteins of which molecular weights were 147.9 and 112.2 kD respectively. However some minor proteins were unique for S. mitis, S. uberis and S. faecalis.

• Archives of Pharmacal Research
• /
• 제20권2호
• /
• pp.197-199
• /
• 1997

In conclusion, benzotriazole analogs prepared in this research showed strong possibility to be photochemically activated DNA cleaving agents. Electrophilic groups such as haloacetoxy groups on the alkyl chain of benzotriazole analogs promote the DNA cleaving ability. Synthesis of 1-(2-Naphthoyl) Benzotriazoles.

• 한국환경성돌연변이발암원학회지
• /
• 제9권1호
• /
• pp.13-22
• /
• 1989

The effect of novobiocin (NOV), and inhibitor of topoisomerase II, on ethyl methanesulfonate (EMS)-or bleomycin (BLM)-induced DNA repair synthesis was examined during the cell cycle of Chinese hamster ovary (CHO)-K1 cells. Three assays were employed in this study: cell survival, alkaline elution and unscheduled DNA synthesis. EMS was effective at killing CHO cells in G1 phase, wheras BLM preferentially killed cells in G2 and S phases. EMS induced the much more amount of DNA damage in G1 phase, while BLM induced in G2 phase than the other phases. The both of pre- and post-treatment with BOV inhibitied EMS- or BLM-induced DNA repair synthesis in G1 and G2 phases, and pretreatment with NOV inhibited more effectively than the post-treated group. These results suggested that CHO cells exhibited a differential sensitivity to cell lethality and DNA damage in relation to cell cycle according to used chemical agents, and that DNA topoisomerase II participated in an initial stage of DNA repair.

• Reproductive and Developmental Biology
• /
• 제28권4호
• /
• pp.211-219
• /
• 2004

The effects of adenosine 5'-triphosphate (ATP) and ATP analogs, P/sub 2y/ purinoceptor agonists, on growth of normal mouse mammary epithelial cells (NMuMG) were examined. Cells were plated onto 24 well plates in DMEM supplemented with 10 % fetal calf serum. After serum starvation for 24 hours, ATP, P/sub 2y/ purinoceptor agonists (AdoPP[NH]P, ATP-α-S, ATP-γ-S, β, γ-me-ATP and 2me-S-ATP), P/sub 2u/ purinoceptor agonist (UTP) and P/sub 2y/ purinoceptor antagonists (Reactive Blue 2, more selective to P/sub 2y/ receptor than PPADS; PPADS) were added. DNA synthesis was estimated as incorporation of 3H-thymidine into DNA (1 hour pulse with 1 μ Ci/ml, 18～19 hours after treatment). ATP, Adopp[NH]P, ATP-α-S or ATP-γ-S, significantly increased DNA synthesis at 1, 10 and 100 μM concentrations with dose-dependency (P<0.05), and the maximum responses of ATP and ATP analogs were shown at 100 μM concentration (P<0.05). The potency order of DNA synthesis was ATP≥ATP- γ -S>Adopp [NH]P>ATP-α-S. β, γ -me-ATP, 2me-S-ATP and UTP did not increase DNA synthesis. In autoradiographic analysis of percentage of S-phase cells, similar results were observed to those of DNA synthesis. Addition of 1, 10 or 100 μM Reactive Blue 2 or PPADS significantly decreased ATP (100 μM)-induced DNA synthesis, however, PPADS was less effective than Reactive Blue 2. In Elvax 40P implant experiment, ATP directly stimulated mammary endbud growth in situ suggesting the physiological regulator of ATP in mammary growth. ATP 100 μM rapidly increased MAPK activity, reaching a maximum at 5 min and then gradually decreasing to the base level in 30 min. ATP analogs, Adopp[NH]P and ATP-γ-S also increased MAPK activity, however, β, γ-me-ATP and 2me-S-ATP did not. The inhibitor of the upstream MAPK kinase (MEK), PD 98059 (25 μM), effectively reduced ATP (100 μM) or EGF(10 ng/ml, as positive control)-induced MAPK activity and DNA synthesis (P<0.05). These results indicate that ATP-induced DNA synthesis was prevented from the direct inhibition of MAPK kinase pathway. Overall results support the hypothesis that the stimulatory effects of normal mouse mammary epithelial growth by addition of ATP or ATP analogs are mediated through mammary tissue specific P/sub 2y/ purinoceptor subtype, and MAPK activation is necessary for the ATP-induced cell growth.

• 한국동물학회지
• /
• 제19권4호
• /
• pp.179-186
• /
• 1976

DNA 回復合成과 染色體交換과의 聯關性을 추구하기 위해 알킬화제 突然變異誘發原인 MMC, MNNG, MMS를 培養한 사람의 淋巴球와 HeLa $S_3$ 細胞에 處理하여 다음과 같은 結果를 얻었다. 1. 이들 알킬화제에 의해 誘發된 DNA 回復合成은 MMC, MNNG, MMS의 濃度가 각각 $3 \\times 10^-7, 1 \\times 10^-6, 5 \\times 10^-4 M$에서 檢出되었다. 이는 MMC가 가장 强力한 DNA 回復合成 誘發原이며 다음이 MNNG 그 다음이 MMS임을 뜻한다. MMC와 MNNG는 濃度增加에 따른 DNA 回復合成에 큰 차이를 보이지 않으나 MMS는 현저한 增加를 보인다. 2. MMC에 의한 染色體異常은 濃度가 增加함에 따라 그 率에 현저한 增加를 보이나 染色體交換率에는 별차이가 없다. 그러나 MNNG는 染色體異常率에 차가 없고 染色體交換은 觀察되지 않았다. MMS는 染色體異常 및 染色體交換 모두 濃度의 增加에 따른 그 率의 增加를 나타낸다. 이러한 結果는 突然變異誘發原에 의한 DNA 回復合成이 染色體交換 및 染色體異常과 직접적인 연관성이 없음을 시사하는 것이다.

• 대한의생명과학회지
• /
• 제3권1호
• /
• pp.11-20
• /
• 1997

신경아세포종 세포 분화의 조절에 대한 연구는 아직 초기 단계에 불과하나 신경아세포종양의 임상적인 치료에 매우 중요한 기초가 된다. 본 연구는 신경아세포종 세포의 분화를 유도 할 수 있는 유용한 시약을 찾아내고자 하는 노력의 일환으로, 잘 알려진 DNA 합성 억제제가 신경 아세포종의 분화를 유도할 수 있는지를 살펴보고자 신경아세포종양 세포의 형태적, 생화학적 및 유전자 발현에 미치는 효과를 살펴보았다. 신경아세포종양으로부터 수립된 세포주, IMR-32 세포에 DNA 합성 억제제인 sodium butyrate, hydroxyurea, cytosine arabinoside를 각각 처리한 결과 처리하지 않은 대조군과는 달리 정상신경 세포 분화시 볼 수 있는 신경 돌기의 성장이 유도됨을 관찰할 수 있었으며 ,신경 전달 물질인 acetylcholine의 합성 효소인 choline acetyltransferase의 활성도가 현저히 증가되었다. 또한DNA합성 억제제를 처리하지 않은 IMR-32세포에서 탐지되지 않았던 c-myc 유전자의 발현이 시약 처리시 확연히 탐지됨을 관찰할 수 있었다. 이러한 실험 결과들은 DNA합성 억제제가 IMR-32세포의 성장을 억제하고 분화를 유도했음을 보여준 것이며, 어린 아이 시기에 많이 발병되는 신경아세포종양의 급속한 악성화나 전이의 억제기전을 제시해 줄 수 있으리라 생각한다.

• Toxicological Research
• /
• 제34권4호
• /
• pp.297-302
• /
• 2018

Cells are constantly exposed to endogenous and exogenous chemical and physical agents that damage their genome by forming DNA lesions. These lesions interfere with the normal functions of DNA such as transcription and replication, and need to be either repaired or tolerated. DNA lesions are accurately removed via various repair pathways. In contrast, tolerance mechanisms do not remove lesions but only allow replication to proceed despite the presence of unrepaired lesions. Cells possess two major tolerance strategies, namely translesion synthesis (TLS), which is an error-prone strategy and an accurate strategy based on homologous recombination (homology-dependent gap repair [HDGR]). Thus, the mutation frequency reflects the relative extent to which the two tolerance pathways operate in vivo. In the present paper, we review the present understanding of the mechanisms of TLS and HDGR and propose a novel and comprehensive view of the way both strategies interact and are regulated in vivo.