• 대한바이러스학회지
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• 제26권2호
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• pp.141-150
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• 1996

본 연구에서는 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있고 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달할 수 있는 바이러스 입자를 생산하는 HIV-1 complementation system을 개발하였고 이 system을 이용하여 $CD4^+$ T 세포에 선택적으로 HIV-1 envelope 당단백질을 발현시켰다. 이 system은 Gag/Gag-Pol expressor와 Env expressor로 구성되어있다. Gag/Gag-Pol expressor는 바이러스 입자 생산에 필요한 구조단백질과 기능단백질을 발현시키지만 packaging signal이 결핍되어 바이러스 입자로 유전자가 들어가지 못하도록 제조되었다. Env expressor는 Tat, Rev와 envelope 당단백질을 발현시키고 packaging signal을 갖고 있어 바이러스 입자로 envelope 유전자가 들어가도록 제조되었다. Gag/Gag-Pol expressor로부터 Gag와 Gag-Pol의 발현은 Rev 단백질을 요구하였고 Env expressor로부터 Rev 단백질 이 제공될 때 Gag와 Gag-Pol 단백질은 효율적으로 발현되었다. Gag/Gag-Pol과 Env expressor로 cotransfection된 COS-1 세포에서 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있는 바이러스 입자가 생산되었다. 생산된 바이러스 입자는 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달하여 envelope 당단백질을 발현시켰고 복제 가능한 자손 바이러스의 생성을 유도하지 못하였다. 본 연구에서 개발된 방법은 $CD4^+$ T 세포에서 envelope 당단백질의 기능을 분석하고 관심 있는 유전자를 $CD4^+$ T 세포에 전달하는 바이러스 입자의 생산에 이용할 수 있다.

• 대한본초학회지
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• 제29권6호
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• pp.73-83
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• 2014

Objectives : This study was investigated the effects of the root of Polygala tenuifolia (POL) on learning and memory impairment induced by chronic cerebral hypoperfusion in rats. Methods : Chronic cerebral hypoperfusion was produced by permanent bilateral common carotid artery occlusion (pBCAO). POL was administered orally once a day (130 mg/kg of water-extract) for 28 days starting at 4 weeks after the pBCAO. The acquisition of learning and the retention of memory were tested on 9th week after the pBCAO using the Morris water maze. In addition, effects of POL on $A{\beta}$ generation and expressions of APP and BACE1 were observed in the hippocampus of rats. Results : POL significantly prolonged the swimming time spent in target quadrant and significantly reduced the swimming time spent in the quadrant far from the target. POL significantly increased the percentage of swim in the targer quadrant in the retention test, while POL was not effective on the escape latencies in the acquisition training trials. POL significantly reduced the levels of $A{\beta}_{(1-40)}$ and $A{\beta}_{(1-42)}$ in the cerebral cortex and the level of $A{\beta}_{(1-42)}$ in the hippocampus produced by chronic cerebral hypoperfusion. POL also significantly attenuated the up-regulation of APP and BACE1 expression in the hippocampus produced by chronic cerebral hypoperfusion. Conclusions : The results show that POL alleviated memory deficit and up-regulation of $A{\beta}$ and BACE1 expressions in the hippocampus. This result suggests that POL may exert ameliorating effect on memory deficit through inhibition of ${\beta}$-secretase activity and $A{\beta}$ generation.

• Journal of Microbiology and Biotechnology
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• 제17권7호
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• pp.1090-1097
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• 2007

Genomic analysis of Thermococcus sp. NA1 revealed the presence of a 3,927-base-pair (bp) family B-type DNA polymerase gene, TNA1_pol. TNA1_pol, without its intein, was overexpressed in Escherichia coli, purified using metal affinity chromatography, and characterized. TNA1_pol activity was optimal at pH 7.5 and $75^{\circ}C$. TNA1_pol was highly thermostable, with a half-life of 3.5h at $100^{\circ}C$ and 12.5h at $95^{\circ}C$. Polymerase chain reaction parameters of TNA1_pol such as error-rate, processivity, and extension rate were measured in comparison with rTaq, Pfu, and KOD DNA polymerases. TNA1_pol averaged one incorrect bp every 4.45 kilobases (kb), and had a processivity of 150 nucleotides (nt) and an extension rate of 60 bases/s. Thus, TNA1_pol has a much faster elongation rate than Pfu DNA polymerase with 7-fold higher fidelity than that of rTaq.

• 대한원격탐사학회지
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• 제34권6_1호
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• pp.969-979
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• 2018

이 연구는 아마존 열대우림 지역에서 획득된 ALOS PALSAR 자료로부터 HH-편파 와 HV-편파 및 VV-편파와 VH-편파 간의 상관계수를 구하였으며, 이로부터 다중편파 SAR의 반사대칭(Reflection Symmetry) 가정에 대한 분석결과를 보고한다. 반사대칭 가정은 다중편파 SAR의 균질한 자연 산란체에서 HH-편파와 HV-편파 및 VV-편파와 VH-편파는 서로 완전 독립적이며 0의 상관계수를 갖는다는 것으로, 이는 다중편파 SAR의 필수적인 cross-talk 보정 계수 획득과정뿐만 아니라 다중편파 SAR 신호의 3-성분 분석법 등의 활용과정에서 흔히 적용되는 가정이다. 특히 아마존 열대우림 지역은 다중편파 SAR의 반사대칭성 보정에 대표적으로 활용되고 있는 국제적 기준분석 지역이다. 분석결과 가정과는 달리 반사대칭 쌍들 간의 상관계수는 0.018에서 0.097의 범위를 나타냈으며, 이는 동종편파와 이종편파 신호 간에 완전 독립적이지 못하며 무시할 수 없을 정도의 상관관계가 존재한다는 것을 지시하였다. 따라서 이와 같은 0이 아닌 상관계수는 향후 국내 다중편파 SAR 검 보정 계수 결정 및 SAR 다중편파 활용과정에서 오차로 작용할 수 있다는 점이 고려되어야 한다.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.16-24
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• 2021

Hepatitis B virus (HBV) genome P-encoded protein HBV DNA polymerase (Pol) has long been known as a reverse transcriptase during HBV replication. In this study, we investigated the impact of HBV Pol on host cellular processes, mainly apoptosis, and the underlying mechanisms. We showed a marked reduction in apoptotic rates in the HBV Pol-expressed HepG2 cells compared to controls. Moreover, a series of assays, i.e., yeast two-hybrid, GST pull-down, co-immunoprecipitation, and confocal laser scanning microscopy, identified the host factor eEF1A2 to be associated with HBV Pol. Furthermore, knockdown of eEF1A2 gene by siRNA abrogated the HBV Pol-mediated anti-apoptotic effect with apoptosis induced by endoplasmatic reticulum (ER) stress-inducer thapsigargin (TG), thus suggesting that the host factor eEF1A2 is essential for HBV Pol's anti-apoptosis properties. Our findings have revealed a novel role for HBV Pol in its modulation of apoptosis through integrating with eEF1A2.

• 생명과학회지
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• 제33권4호
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• pp.315-324
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• 2023

폴리코사놀의 콜레스테롤 감소 효과에 대한 기전은 아직 명확하게 규명되지 못하고 있다. 최근 몇몇 연구들은 지방산 합성 경로를 통한 콜레스테롤 합성의 조절에 sterol regulatory element-binding proteins(SREBP-1c)의 역할을 제시하였다. 그러나 현재까지 SREBP-1c에 의해 조절되는 지방산 합성에서 폴리코사놀의 효과에 대한 연구는 전무하다. 그러므로 본 연구의 목표는 SREBP-1c에 의해 매개되는 지방산 합성이 폴리코사놀의 콜레스테롤 감소 효과와 관계하는지를 조사하는 것이다. 7주령의 C57BL/6 수컷 생쥐를 7개군(군당 7마리)으로 나누고 8주간 다음과 같이 처리하였다; 1) 정상식이군(정상 대조군), 2) 고지방식이군(high-fat diet, HFD, 음성대조군), 3) 고지방식이+에탄올처리군(Pol-0), 4) 고지방식이+1 mg/kg 폴리코사놀처리군(Pol-1), 5) 고지방식이+2 mg/kg 폴리코사놀처리군(Pol-2), 6) 고지방식이+4 mg/kg 폴리코사놀처리군(Pol-4),7) 고지방식이+simvastatin 50 ㎍/kg 처리군(양성 대조군). 폴리코사놀과 simvastatin은 고지방식이를 유지하는 동안 매일 동일 시간에 처리하였으며 체중과 음식섭취량은 8주 동안 매주 측정하였다. 8주 후, 혈중 콜레스테롤 수치를 측정하였으며, 간의 조직학적 분석과 SREBP-1c와 지방산의 발현을 조사하였다. 폴리코사놀은 농도-의존적으로 체중과 음식섭취량을 감소시켰다. 혈중 콜레스테롤 수치는 Pol-1과 Pol-4군에서 유의하게 감소하였으며, SREBP-1c와 FAS의 발현 역시 Pol-4 군에서 유의하게 감소하였다. 이러한 결과들은 폴리코사놀의 콜레스테롤 감소 효과가 SREBP-1c와 FAS의 발현 억제에 기인하여 일어날 수 있음을 시사한다.

• 대한본초학회지
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• 제31권1호
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• pp.7-15
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• 2016

Objectives : Polygalae Radix (POL) has an ameliorating effect on learning and memory impairment caused by cerebral hypoperfusion. In regard to POL's action mechanism, this study was carried out to investigate the effects of POL on oxidative damage and neuronal apoptosis induced by cerebral hypoperfusion in rats.Methods : The cerebral hypoperfusion was induced by permanent bilateral common carotid artery occlusion (pBCAO) in Sprague-Dawley rats. POL was administered orally once a day (130 mg/kg of water-extract) for 28 days starting at 4 weeks after the pBCAO. Superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels in the brain tissue were measured using ELISA method. Expressions of 4-hydroxynonenal (4HNE) and 8-hydroxy-2'- deoxyguanosine (8-OHdG) were observed using immunohistochemistry. In addition, neuronal apoptosis was evaluated with Cresyl violet staining, TUNEL labeling, and immunohistochemistry against Bax and caspase-3.Results : POL treatment significantly increased SOD activities and significantly reduced MDA levels in the cerebral cortex. The up-regulations of 4HNE and 8-OHdG expression caused by pBCAO in the CA1 of hippocampus were significantly attenuated by POL treatment. POL treatment also restored the reduction of CA1 thickness and CA1 neurons caused by pBCAO and significantly attenuated the apoptotic markers including TUNEL-positive cells, Bax, and caspase-3 expression in the CA1 of hippocampus.Conclusions : The results show that POL attenuated the oxidative damage in brain tissue and neuronal apoptosis in the hippocampus caused by the cerebral hypoperfusion. It suggests that POL can be a beneficial medicinal herb to treat the brain diseases related to cerebral hypoperfusion.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7375-7379
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• 2013

The main aim of this study was to investigate the roles of GST-${\pi}$ and $pol{\beta}$ genes in the chemoresistance of esophageal carcinoma cells. Eukaryotic expression vectors containing each gene were constructed and transfected into EC9706 cells, and the biological effects of the two genes assessed based on a resistance index. We additionally investigated the in vitro and in vivo anti-resistance effects of GST-${\pi}$ and $pol{\beta}$ genes using recombinant lentiviruses carrying siRNAs against the two genes. Our results showed that upregulation of GST-${\pi}$ and $pol{\beta}$ genes suppresses chemosensitivity of esophageal carcinoma cells to cisplatin, while downregulation of these two genes with RNAi technology reverses this chemoresistance. Multi-site injection of recombinant lentivirus targeting the GST-${\pi}$ gene into transplanted cDDP tumors effectively reversed their chemoresistant phenotype. However, the same treatment against the $pol{\beta}$ gene did not lead to significant efficacy against chemoresistance.

• 대한원격탐사학회지
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• 제33권1호
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• pp.47-60
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• 2017

The permafrost active layer plays an important role in permafrost dynamics. Ecological patterns, processes, and water and ice contents in the active layer are spatially and temporally complex depending on landscape heterogeneity and local-scale variations in hydrological processes. Although there has been emerging interest in the application of optical remote sensing techniques to permafrost environments, optical sensors are significantly limited in accessing information on near surface geo-cryological conditions. The primary objective of this study was to investigate capability of L-band SAR data for monitoring spatio-temporal variability of permafrost ecosystems and underlying soil conditions. This study exploits information from different polarimetric SAR observables in relation to permafrost environmental conditions. Experimental results show that each polarimetric radar observable conveys different information on permafrost environments. In the case of the dual-pol mode, the radar observables consist of two backscattering powers and one correlation coefficient between polarimetric channels. Among them, the dual-pol scattering powers are highly sensitive to freeze/thaw transition and can discriminate grasslands or ponds in thermokarst area from other permafrost ecosystems. However, it is difficult to identify the ground conditions with dual-pol observables. Additional backscattering powers and correlation coefficients obtained from quad-pol mode help understanding seasonal variations ofradar scattering and assessing geo-cryological information on soil layers. In particular, co-pol coherences atHV-basis and circular-basis were found to be very usefultools for mapping and monitoring near surface soil properties.

• Restorative Dentistry and Endodontics
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• 제4권1호
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• pp.11-16
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• 1978

This experimental study was made to investigate the effect of the "Hi-Pol" composite resin on the human dental pulp. 38 cavities of healthy permanent teeth were divided into 5 groups which were used as experimental materials. Group 1: Zinc Oxide-Euginol paste was applied to the cavities as controls $\cdots\;\cdots8$ cases Group 2: "Hi-Pol"*filling with Dycal** base $\cdots\;\cdots9$ cases Group 3: "Hi-Pol" filling without Dycal base $\cdots\;\cdots9$ cases Groud 4: Adaptic*** filling with Dycal base $\cdots\;\cdots6$ cases Group 5: Adaptic filling without Dycal base $\cdots\;\cdots6$ cases The treated teeth were extracted after 1 week, 2 weeks, 3 weeks and 4 weeks and processed for histological study. The results obtained from this experimental study were as follows; 1. The controls applied zinc oxide-eugenol showed the minimal pulp response and group 3 and group 5 showed the most severe pulp response. 2. In group 3 and group 5, the severity of pulp response increased in intensity according to the time elapsed. 3. In group 2 and group 4, the mild pulp response was found in earlier stage and the repairing process could be observed in later stage. * Boo-Pyung Co., Korea ** L. D. Caulk Co., Milford, Del. 19963 *** Johnson and Johnson Co., New Brunswick, NJ 08903.