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        검색결과 114

        63.
        2012.06 구독 인증기관·개인회원 무료
        Adipose tissue-derived mesenchymal stem cells (ASCs) are very interesting in several laboratory animals and humans because they are easy to harvest and expand to generate millions of cells from a small quantity of fat. ASCs are known as useful materials for clinical applications in human cell therapy and as a donor cell in somatic cell nuclear transfer (SCNT). Here, we investigated if 1) minipig ASCs can be isolated, self-renewed and differentiated into multiple tissue lineages, 2) ASCs can be a suitable donor cell type for generation of cloned pig. In order to isolate ASC, adipose tissues were collected from inguinal region of a 6-year-old female minipig. The ASCs were attached to the culture dish with a fibroblast-like morphology. They expressed cell-surface marker characteristics of stem cell, underwent osteogenic, adipogenic, myogenic, neurogenic and chondrogenic differentiation when exposed to specific differentiation-inducing conditions. To investigate its potential as donor cell for cloning, we respectively carried out SCNT using ASC, adult skin fibroblast (ASF) and fetal fibroblast (FF) derived from same minipig. The ratio of blastocysts to 2-cell embryos and total cell number of blastocysts were monitored as experimental parameters. In results, cleavage and developmental competence to blastocysts rate showed no significant difference among the three groups. On the other hand, total cell numbers of blastocysts derived from ASC and FF were significantly higher than in ASF (89±7.9 and 105±5.5 vs. 57.5±5.2, respectively). Our results demonstrated that ASC have potential compared to ASF and FF in terms of the in vitro development and blastocyst formation ability. In further study, we will investigate the in vivo developmental ability of ASC as donor cell for pig cloning. * This study was supported by IPET (#311011-05-1-SB010), RNL Bio (#550-20120006), Institute for Veterinary Science, the BK21 program, TS Corporation and Optifarm Solution.
        64.
        2012.05 구독 인증기관·개인회원 무료
        The resistance levels to carbamate (CB) and organophosphate (OP) insecticides were determined by topical application in 14 field strains of Nilaparvata lugens. The resistance levels to CB and OP were 1.3~47.5-fold and 1.4~14.4-fold higher than a susceptible strain, respectively. A quantitative sequencing (QS) protocol was established to determine the allele frequencies of four acetylcholinesterase point mutations putatively associated with CB and OP resistance. The allele frequencies of the four mutations (G119A, F/Y330S, F331H and I332L) in field strains ranged from ca. 0.0~51.7%, 0.0~88.9%, 2.5~47.7%, 5.1~56.0% and 6.7~57.3%, respectively. The F331H and I332L were tightly linked each other, suggesting these mutations may occur simultaneously. In the correlation analysis, G119A was not well correlated with actual resistance levels (r2= < 0.232), whereas F331H and I332L showed a better correlation with the resistance levels of benzofuranyl methylcarbamates (r2= 0.595). This finding indicates that F331H and I332L mutation frequencies may be used as molecular markers for detecting carbamate resistance in N. lugens. A QS protocol detecting the F331H and I332L mutation frequencies would be employed as a supportive tool for rapid monitoring of CB insecticide resistance levels in N. lugens
        65.
        2012.05 구독 인증기관·개인회원 무료
        The screening of effective lethal genes was conducted via the systemic delivery of dsRNA for the RNA interference (RNAi)-based management of Tetranychus urticae. Four candidate genes (coatomer protein complex, T-COP; M1 metalloprotease, T-M1MP; Ribosomal protein S4, T-RPS4; A subunit of V-ATPase, T-VATPase) with a reference genes (EGFP) were tested for the experiment. Translocated dsRNA to the leaf disc (ca. 30 mm diameter) was detected at 12 h post-treatment, indicating that dsRNA could move through leaf veins. In the evaluation of mortality, the T-COP, T-RPS4 and T-VATPase exerted moderate levels of toxicity at 72 h post-treatment among four dsRNA tested. Knockdown of the target genes were confirmed by quantitative PCR, suggesting that RNAi of target genes was accomplished by feeding dsRNA. In summary, the dsRNA delivery via leaf disc was effective in screening lethal genes, and some genes, such as T-COP, T-M1MP, T-RPS4 and T-VATPase, can be applicable for establishing a RNAi-based control system against T. urticae.
        66.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Ag2O를 첨가한 압축 벤토나이트에 대하여 관통 확산법으로 요오드 이온의 이동 특성을 관찰하였다. Ag2O를 첨가하지 않은 압축 벤토나이트와 마찬가지로 Ag2O를 첨가한 압축 벤토나이트에서도 요오드 이온은 확산에 의하여 이동하는데, Ag2O를 첨가한 압축 벤토나이트는 Ag2O를 첨가하지 않은 압축 벤토나이트에 비하여 요오드 이온의 초기 누출 시간이 지연되는 것으로 나타났다. Ag2O를 첨가한 압축 벤토나이트에서 요오드 이온의 초기 누출 시간 지연은 확산 용액으로 순수 요오드 이온 수용액을 사용하였을 때 뿐만 아니라 0.1 M NaCl-요오드 이온 수용액을 사용하였을 때에도 관찰되었다. 또한 Ag2O를 첨가한 압축 벤토나이트의 겉보기 확산 계수는 Ag2O를 첨가하지 않은 압축 벤토나이트의 겉보기 확산 계수보다 낮은 값을 나타내었다. Ag2O를 첨가하지 않은 압축 벤토나이트의 유효 확산 계수는 기존 문헌에 보고된 값 과 거의 일치하는 결과를 얻었으며, Ag2O를 첨가한 압축 벤토나이트에서 요오드 이온의 유효 확산 계수는 Ag2O 첨가에 따라 대체적으로 감소하는 경향을 나타내었다.
        4,000원
        67.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to reveal how EA affects BAX and NF-kB involved in cell deaths from global ischemia, and to do this, observes the changes of BAX and NF-kB caused by EA application after transient global ischemia. The experimental method is to give rise to global ischemia and apply EA to 27 SD rats with the particulars of being six-week-old, male, around-300 gram-weighing, and adapted to laboratory environment for more than a week, and divide them into three groups, that is, GV20 EA group(n=9), L14 EA group(n=9), no-treatment GI group(n=9), and then observe their changes of BAX and NF-kB at the time lapse of 6 hours, 9 hours and 12 hours after ischemia, using western blotting. The numerical decrease of BAX expression at the time lapse of 9 hours after EA application, though not statistically significant, was observed in GV20 EA group and L14 EA group, and the NF-kB expression appeared statistically significant decrease in GV20 EA group and L14 EA group, but the expression was higher in the group with EA application. Therefore, EA application at the early phase of global ischemia is considered to affect BAX and NF-kB and play a positive role in decreasing apoptosis and cell deaths by inflammation.
        4,000원
        68.
        2009.12 KCI 등재 구독 인증기관·개인회원 무료
        Cordycepin (3’-deoxyadenosin), a polyadenylation specific inhibitor, is the main functional component in Cordyceps militaris which is one of the top three famous traditional Chinese medicine. It has been shown to possess many pharmacological activities including immunologically stimulating, anti-cancer, anti-bacterial, and anti-virus, anti-infection effects. However, its anti-cancer molecular mechanisms are poorly understood. In this study, the apoptotic effects by cordycepin were investigates in human leukemia cells. Treatment of cordycepin significantly inhibited cells growth in a concentrationdependent manner by inducing apoptosis, as evidenced by morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of sub-G1. Induction of apoptosis by cordycepin was associated with modulation of Bcl-2 and inhibitor of apoptosis proteins (IAP) family expression. Cordycepin also increased reactive oxygen species (ROS) generation, activation of casepase-3, caspase-8, caspase-9, cleavage of poly(ADP-ribose) polymerase (PARP), β-catenin and phospholipase C (PLC)-γ1 protein. The quenching of ROS generation by N-acetyl-L-cysteine administration, a scavenger of ROS, reversed the cordycepin-induced apoptosis effects. Theresults suggested that cordycepin may be a potential chemotherapeutic agent for the treatment of leukemia patients [This work was supported by Blue-Bio Industry RIC at Dong-Eui University as a RIC (08-06-07) program of ITEP under Ministry of Knowledge Economy].
        73.
        2006.06 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the effect of IRES controlled reporter gene on screening and production of recombinant human erythropoietin (EPO) proteins from cultured CHO cells. The cDNA was cloned for EPO from human liver cDNA. Using site-directed mutagenesis, we generated recombinant human EPO (rhEPO) with two additional N-glycosylations (Novel erythropoiesis-stimulating protein: NESP). Wild type hEPO and NESP were cloned into expression vectors with GFP reporter gene under regulatory control of CMV promoter and IRES so that the vectors could express both rhEPO and GFP. The expression vectors were transfected to cultured CHO-K1 cells. Under microscopy, expression of GFP was visible. Using supernatant of the culture, ELISA assay, immunocytochemistry and in vitro assay using EPO dependant cell line were performed to estimate biological activity to compare the production characteristics (secretion levels, etc.) between rhEPO and NESP. The activity of NESP protein, obtained by mutagenesis, was described and compared with its rhEPO counterpart produced under same conditions. Although NESP had less secretion level in CHO cell line, the biological activity of NESP was greater than that of rhEPO. These results are consistent with previous researches. We also demonstrated that rhEPO and GFP proteins expressed simultaneously from transfected CHO cell line. Therefore we conclude that use of GFP reporter gene under IRES control could be used to screen and produce rhEPO in cultured CHO cells.
        4,000원
        76.
        1994.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        D-xylan은 최근 대체 에너지원인 알콜 생산의 기질로서 주목받고 있을 뿐만 아니라 butanol과 butandiol과 같은 유기 용매와 xylitol과 같은 감미료, xylooligosaccharide와 같은 bifidogenic factor 등의 원료로 사용된다. 본 논문에서는 발효된 톱밥으로부터 xylanase 강력 생산성 균주를 분리하고 제 특성을 확인하여 Bacillus sp. GS로 동정하였다. Xylanase 생산성을 높이기 위해 효소 생산 배지 성분과 배양 조건을 최적화 하였는데, 각각 xylan 1.25%, yeast extract 0.1%, NaNO_3 1.2%, K_2HPO_4 0.1%, MgSO_4 0.02%, mineral salt 0.005%와 pH 6.5, 배양 온도 37℃였다.
        4,000원
        77.
        2018.11 KCI 등재 서비스 종료(열람 제한)
        고무화합물 형태로 구성된 조영제의 병에 Syringe Connector의 Spike를 연결 시 고무의 찢김 정도를 알아보고 찢김 및 분쇄로 인한 합성고무의 혼입 유무와 분쇄된 합성고무가 검출 시 분쇄물의 크기를 실험을 통해 알아보고자 하였다. 그 결과 찢김 정도의 경우 Syringe Connector의 끝과 최초 접촉하는 앞면이 약 3.14±0.04 ㎜로 뒷면 보다 많이 찢겼으며, 실험 대상인 10 병의 조영제에서 평균 7 개에서 15 개로 모두 분쇄물이 검출되었다. 검출된 분쇄물을 이용하여 크기를 측정한 결과 평균크기는 약 7.89±0.31 ㎛이었다. 향 후 다양한 실험 및 분석방법을 통한 추가실험과 더불어 흡인된 분쇄물 차단을 위한 미세 필터타입 자동주입장치의 개발이 필요하며, 분쇄물 유입 시 치명적 사고를 대비하여 관련기관의 관심 또한 필요할 것으로 사료된다.
        78.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a 1-m2 radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.
        79.
        2017.11 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        장 건강에 유익한 프리바이오틱스 소재를 개발하기 위하여 배변을 촉진하는 효능을 지닌 붉은팥을 식품 발효에 이용되는 Bacillus subtilis KCCM 11965P로 발효하여 다음과 같은 결과를 얻었다. 붉은팥의 일반성분은 회분 3.35±0.04%, 조단백질 21.1±0.19%, 조지방 0.35±0.02% 함 유되었다. 붉은팥 원물 1%, 3%, 5%와 Bacillus subtilis KCCM 11965P 3% (v/v)를 접종하여 0, 24, 48, 72시간 배양 하였다. 배양액의 총균수를 측정한 결과 붉은팥 원물을 3% 첨가한 후 72시간 배양군에서 Bacillus subtilis KCCM 11965P 발효가 가장 적합하였다. 발효 시간에 증가함에 따라 총 폴리페놀 함량과 DPPH 라디칼 소거활성이 증가하였다. Protease 활성은 붉은팥 원물 5% 첨가한 후 72시간 배양한 군(2.69±0.003 unit/mL)에서 활성이 가장 높았다. 발효시간과 붉은팥 원물 첨가 농도가 증가함에 따라 α -amylase 활성도 증가하였으며, 붉은팥 원물 5% 첨가한 후 72시간 배양한 군에서 0시간 배양군(1.0±0.1 unit/mL) 보다 26.0±0.2 unit/mL로 증가하였다. Bacillus subtilis KCCM 11965P로 72시간 배양한 후 유리아미노산을 측정한 결과 leucine은 붉은팥 원물 5% 첨가한 0시간 배양군 5.22 mg/L 에서 67.59 mg/L로 증가하였으며, 비필수아미노산인 tyrosine은 5% 첨가 0시간 배양군 10.08 mg/L에서 259.35 mg/L로 증가하였다. 이와 같이 Bacillus subtilis KCCM 11965P로 붉은팥을 발효하면 항산화 활성, protease 효소활성, 및 α-amylase 효소 활성이 증가하였으며, 유리아미노 산과 유기산이 증가하였다. 붉은팥을 발효하는데 Bacillus subtilis KCCM 11965P가 적합할 것으로 판단되며, 붉은팥은 프로바이오틱스를 활성화시켜 장 건강을 증진시킬 수 있는 프리바이오틱스 소재로 개발할 수 있는 가능성을 시사 하였다.
        80.
        2017.05 서비스 종료(열람 제한)
        Background : Korean mountain ginseng (Panax ginseng C.A. Meyer) are difficult to industrially apply because of its scarcity and high cost. Advances in plant biotechnology have made it possible to produce mountain ginseng on a large scale using adventitious root cultures in bio-reactors. This study was conducted to develop a cosmetic emulsion using ginsenoside and physiological activity - enhanced raw materials by fermentation process. Methods and Results : Wild ginseng adventitious roots were fermented with Pediococcus pentosaceus HLJG 0702 (KACC 81017BP). ginsenoside contents was analysed by using HPLC. Antioxidant activity was measured by DPPH and ABTS radical scavenging activity and whitening effect was measured by tyrosinase inhibitory activity. After microfluidizer processing was performed to prepare emulsions with homogenized particles, particle size and distribution were measured through a transmission electron microscop e(TEM). Particle stability compares pH, viscosity, light and zeta potential. When fermented with Pediococcus pentosaceus HLJG 0702, the highest change rates of Rg3, Rk1 and Rg5 were shown and the antioxidant activity was increased. The whitening effect was 73.2 ± 0.9% when treated at 100 ㎍/㎖, 1.5 times higher than the control. The optimum particle size and distribution were shown to be 418.0 ± 14.9 ㎚ for 6 times treatment with 0 - 10 times microfluidizer treatment. Stability was about 3% in pH, viscosity and light test. the zeta potential was found to be homogeneous at –33.33 mV. Conclusion : Pediococcus pentosaceus HLJG 0702 Fermented Wild ginseng adventitious roots were found to have effective ingredients and improved physiological activity. We have also developed emulsions that exhibit optimal particle size and distribution
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