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        검색결과 875

        243.
        2018.11 구독 인증기관·개인회원 무료
        Generally, in vivo, primary oocytes are grown and matured into secondary oocytes in the ovarian follicles. Quality of the oocytes matured in vivo is higher than that of oocytes matured in vitro, indicating the importance of materializing the microenvironment of ovarian follicles for production of high quality oocyte. Therefore, we tried to mimic the stiffness of ovarian follicles using an agarose as a biocompatible natural polymer. Unfortunately, to date, there are no many reports on whether the quality of porcine oocytes can be increased effectively under the soft matrix. Accordingly, we tried to evaluate the effects of IVM using different mechanical properties of agarose substrate on developmental competence of porcine oocytes. Agarose substrate was constructed and cumulus-oocyte-complexes (COCs) retrieved from porcine medium antral follicles were matured on non-coated (control) culture dish or dishes coated with 1% and 2% (w/v) agarose substrate. Then, cumulus expansion, embryonic development after parthenogenetic activation, and gene expression level were analyzed and compared. As the results, significant increase in blastocyst formation and cumulus expansion were detected in COCs matured on 1% (w/v) agarose substrate compared with control. Moreover, oocytes of COCs matured on 1% (w/v) agarose substrate showed significantly higher BMP15 expression level compared with control. Pro-apoptotic gene BAX expression was significantly increased in oocytes of COCs matured on 2% (w/v) agarose substrate compared with control. In the glycolytic enzyme phosphofructokinase (PFKP) gene expression, cumulus cells of COCs matured on agarose substrate showed significantly higher PFKP expression than control while they showed significantly lower BAX expression than control. These results demonstrated that quality of porcine oocytes could be increased efficiently by the IVM of immature oocytes on the soft culture matrix using agarose.
        244.
        2018.11 구독 인증기관·개인회원 무료
        This study was conducted to evaluate the effects of insulin and epidermal growth factor (EGF) in a in vitro growth (IVG) medium on oocyte growth, in vitro maturation (IVM) and embryonic development of pig oocytes derived from small antral follicles (SAF) less than 3 mm in diameter. SAF oocytes were cultured for 2 days to induce IVG in alpha-minimal essential medium supplemented with 1 mM dbcAMP and 15% (v/v) fetal bovine serum. After IVG culture, oocyte maturation was induced by culturing IVG oocytes in IVM medium for 44 h. IVM oocytes that extruded the first polar body were selected and induced for parthenogenesis (PA) by applying electric stimulus. SAF oocytes cultured under the insulin treatment showed a significantly increased (P < 0.05) nuclear maturation (73.8%) compared to those cultured with insulin and EGF (59.8%). After PA, the proportions of blastocysts based on the number of metaphase II oocytes were significantly higher (P < 0.05) in oocytes that were cultured for IVG with insulin, EGF, and insulin + EGF (32.4%, 35.2%, and 34.8%, respectively) than in control (22.9%). IVG oocytes treated with insulin showed an increased oocyte diameter (116.3 μm) compared to those treated with insulin and EGF (114.0 μm) (P < 0.05). Intra-oocyte GSH content significantly increased (1.07 pixels/oocyte) by insulin treatment during IVG compared to that of oocytes treated with insulin + EGF (0.78 pixels/oocyte). These results demonstrate that IVG culture of SAF oocytes under insulin or/and EGF treatment supports oocyte maturation and improves embryonic development to the blastocyst stage after PA in pigs.
        245.
        2018.11 구독 인증기관·개인회원 무료
        U0126 is a highly selective inhibitor of both MEK1 and MEK2, a type of MAPK/ERK kinase. This study was conducted to evaluate the effect of U0126 treatment during in vitro maturation (IVM) on nuclear maturation, intra-oocyte glutathione content, and embryonic development after parthenogenesis (PA). U0126 (5 μM) was supplemented to IVM medium during the first 0 (control), 2, and 4 h. The basic medium used for IVM was medium-199 supplemented with 10% (v/v) porcine follicular fluid (standard), 0.6 mM cysteine, 0.91 mM pyruvate, 75 μg/ml kanamycin, and 1 μg/ml insulin. Immature pig oocytes were matured for 44 h and then oocytes reached metaphase II stage were electrically activated to induce PA. The in vitro culture medium for embryonic development was porcine zygote medium-3 containing 0.3% (w/v) fatty acid-free BSA. When immature oocytes were treated with U0126 during the first 0, 2, 4 h of IVM culture, nuclear maturation was significantly (P < 0.05) increased by the U0126 treatment for 4 h (96.2 ± 1.3%) compared to standard IVM (90.6 ± 2.1%). Cleavage of PA embryos was significantly increased by 4 h- treatment (90.6 ± 2.2%) compared to standard medium (83.9 ± 1.8%). In addition, blastocyst formation of PA embryos was significantly (P < 0.05) increased by the treatment for 4 h (55.8 ± 5.7%) compared to 2 h (38.1 ± 6.1%). The glutathione contents in IVM oocytes were not altered by the U0126 treatments for 0, 2, and 4 h (1.28 ± 0.10, 1.16 ± 0.09, and 1.10 ± 0.09, respectively). Our results demonstrated that 5 μM U0126 treatment during the first 4 h of IVM showed positive effects on nuclear maturation, cleavage, and embryonic development in pigs.
        246.
        2018.11 구독 인증기관·개인회원 무료
        Poor embryo quality and low blastocyst formation have been major limitations in establishment of cloned embryonic stem cells and production of cloned animals through somatic cell nuclear transfer (SCNT). Aggregation of embryos is a promising method for improving developmental competence of blastocysts. The aim of this study was to improve the blastocyst formation and the quality of parthenogenetic (PA) pig embryos by the aggregation of blastomeres at the 4-cell stage that were cultured in various type of culture dishes with or without phytohemagglutinin (PHA). The PA embryos were produced by the general method of our laboratory. On Day 2 after PA, the zona pellucida of 4 cell-stage embryos were removed by treatment with 0.5% (wt/vol) pronase solution. The 3x zona-free blastomere (ZFB) were randomly distributed in each of the following treatments for aggregation. ZFB were cultured for 5 days at 39℃ in an atmosphere 5% CO2, 5% O2, and 90% N2. In Experiment 1, effect of culture dishes on the aggregation efficiency and developmental competence of PA embryos were investigated. ZFB were cultured on non-coated (control) culture dish or dishes coated with 1% (wt/vol) agarose substrate (AS) or Well of the Well in dishes coated with 1% (wt/vol) agarose substrate (WAS). The ZFB cultured in WAS showed significantly higher (P<0.05) aggregation (81.2%) than AS and control (21.6-45.5%). The mean cell number in blastocysts derived from AS and WAS (81.4-89.3 cells/blastocyst) was significantly higher (P<0.05) than that of control (63.8 cells/blastocyst). In Experiment 2, effects of 150 ug/ml PHA treatment on the aggregation efficiency and developmental competence of embryos were investigated. The ZFB cultured in AS with PHA showed a higher (P<0.05) aggregation rate (90.0%) than that in AS without PHA, control with PHA, and control (39.2%, 57.9% and 17.5%, respectively). In conclusion, aggregation of porcine ZFB treated with PHA and agarose substrate could be a useful technique for producing improving blastocyst development with increased mean cell number of blastocysts in pigs.
        247.
        2018.11 구독 인증기관·개인회원 무료
        Endoplasmic reticulum (ER) stress is well known as a suppressor in osteoblast differentiation and activating transcription factor 3 (ATF3) could be induced by a various extracellular signals including cytokines, hormones, DNA damage. Up to date, although the role of ATF3 have been studied, the function of ATF3 in osteoblast differentiation is still not clear yet. Our study showed that expression level of ATF3 could be incresed by tunicamycin which is ER stress inducer in preosteoblasts. BMPs, which are secreted by osteoblasts, can be important regulators in osteogenic differentiation. The stress-responsive transcription factor ATF3 is a negative regulator of osteoblast differentiation in MC3T3-E1 cells. In this study, we verified that BMP2-stimulated osteoblast differentiation could be inhibited by over-expressed ATF3 through regulating alkaline phosphatase (ALP) expression and activation.
        251.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        겨울철에 열손실을 줄이기 위해 많은 온실에서 보온커튼을 사용하고 있다. 그러나 적절한 보온커튼을 선택할 때 판단 자료로 활용할 수 있는 명확한 기준이 없는 실정이며 이를 위해서는 보온재의 보온 특성에 대한 정량적인 값이 필요하다. 본 연구에서는 BES를 사용하여 보온커튼의 관류열전달계수를 산정하는 시뮬레이션 모델을 개발하였다. 일중 및 이중 PE필름 피복에 대한 관류열전달계수의 실험값을 사용하여 시뮬레이션 결과를 검증하였다. 검증된 모델을 사용하여 문헌에서 제시된 각종 열적 특성을 가진 보온커튼에 대한 관류열전달계수를 산정하고 비교분석하였다. 개발된 시뮬레이션 모델은 다양한 보온커튼의 관류열전달계수를 산정하는데 활용될 수 있을 것이며, 제시된 관류열전달계수는 보온커튼의 성능을 정량적으로 비교하는데 유용하게 활용 될 수 있을 것으로 판단된다.
        4,000원
        252.
        2018.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The DEEP-South (the Deep Ecliptic Patrol of the Southern Sky) photometric census of small Solar System bodies produces massive time-series data of variable, transient or moving objects as a by- product. To fully investigate unexplored variable phenomena, we present an application of multi-aperture photometry and FastBit indexing techniques for faster access to a portion of the DEEP-South year-one data. Our new pipeline is designed to perform automated point source detection, robust high-precision photometry and calibration of non-crowded fields which have overlap with previously surveyed areas. In this paper, we show some examples of catalog-based variability searches to find new variable stars and to recover targeted asteroids. We discover 21 new periodic variables with period ranging between 0.1 and 31 days, including four eclipsing binary systems (detached, over-contact, and ellipsoidal variables), one white dwarf/M dwarf pair candidate, and rotating variable stars. We also recover astrometry (< ±1–2 arcsec level accuracy) and photometry of two targeted near-earth asteroids, 2006 DZ169 and 1996 SK, along with the small- (0.12 mag) and relatively large-amplitude (0.5 mag) variations of their dominant rotational signals in R-band.
        4,600원
        253.
        2018.10 구독 인증기관·개인회원 무료
        후각 신경 시스템은 일반 생활 환경에서 많은 다양한 화학 물질을 인식하고 구별한다. 곤충에서는 다양한 화학 물질을 기호적 또는 회피적인 특이성을 부여하고 이를 구분해 낼 수 있는 고도로 발달된 후각신경 수용체들로 구성된 냄새 맡는 (odorant-gated) 이온 채널 군을 진화시켰다. 최근에 후각 수용체와 단백질을 포함한 olfaction 관련한 진딧물 게놈 밝혀졌고, 초파리에서 다양하게 분화되어 있는 후각 수용체들이 보고되고 있다. 후각 신경 수용체의 유전체는 매우 높은 보전적인 염기 서열을 가지고 있으며, 체계적인 신호 전달 시스템을 갖추고 있다. 대표적 수용체인 odorant-gated ion channels comprised of a highly conserved co-receptor (Orco)는 중심 구멍 주위에 대칭 적으로 배열된 4 개의 서브 유닛을 갖는 homotetramer 채널 구조를 가지고 있다. 이는 인체 내에 존재하는 7-transmembrane receptor와 매우 유사한 구조를 형성하고 있고, 신경전달물질의 수용체와 매우 유사한 구조적 형태 및 gating mechanism을 가지고 있다. 본 연구에서는 초파리에서 분리한 후각 신경 수용체 하위 유형인 OR65 유전자 분리하여 세포 발현 시켜 Xenopus oocyte를 이용하여 Whole cell voltage clamp recording을 실시하였다. 본 수용체의 성공적인 발현 이후 유해 해충 유인제 개발 회사인 마이크로자임의 미생물 배양 추출물을 이용해서 후각 신경 수용체 활성 조절 여부를 연구하였다. 미생물 배양 추출물을 10,000배 희석한 recording media에서 수용체의 활성을 확인하였고, 이를 농도 별로 처리하여 농도 의존성 수용체 활성 작용을 확인하였다. 따라서 곤충의 후각 신경 수용체 활성 조절 시스템을 이용하여 유인물질 또는 기피 물질을 발굴할 수 있으며, 본 연구를 통해서 MZ01은 곤충 수용체 OR65를 활성 시킴으로써 유인 현상을 나타내며, 본 연구를 통해서 현장에서 검증된 미생물 배양 추출물의 성능을 과학적 분석으로 결과를 제시하였다.
        254.
        2018.10 구독 인증기관·개인회원 무료
        Schizandra chinensis(Turcz.) Bail is one of the local special crops grown in Mungyeong, more than 70% of Gyeongbuk province in South Korea, and various pests are emerging due to recent climate change and intensive cultivation. Scirtothrips dorsalis(Hood) are the most damaging pests among the insects that occur in the Schizandra chinensis(Turcz.), mainly affecting fruit quality, yield and quality. The survey was conducted from February 2017 to September 2018 in three locations in Mungyeong area. Blue and yellow traps were used to investigate the occurrence patterns and the degree of damage. As a result of the survey, Scirtothrips dorsalis(Hood) occurred first in flowering period in May, and then occurred in fruits. The occurrence density was highest in July. It was confirmed that the attractiveness of each trap color was blue in the early stage of growth and yellow in the late stage but there was no significant difference in the whole.
        255.
        2018.10 구독 인증기관·개인회원 무료
        The purpose of the present study was to evaluate if main domestic vector mosquitoes, Aedes albopictus as a diurnal species and Culex pipiens as a nocturnal species, have color preference for blood feeding activity. Laboratory evaluations were performed and compared to assess color attractiveness using seven fundamental colors including black, white, red, yellow, green, blue, and purple. The test bodies selected for these experiments were BioGents Sentinel traps (BG traps) with 20g dry ice in each falcon tube, which covered outside of the traps attached with each different color of vinyl sheets. In each experiment, a pair of BG traps was placed 0.6 m away from each other in a 1.8 m x 3.7 m x 1.8 m screened enclosure. The enclosure maintained at 26±2℃, 65±5% RH, and 100 lux illumination. Evaluations were performed for two hours between 10:00 and 16:00 for each 25 Ae. ablopictus females and 15 hours from 18:00 to 9:00 for each 25 Cx. pipiens females. The attraction rates were determined by a series of 42 simultaneous pairs of sample counts of the number of mosquitoes caught in the traps at every 30 minutes. As a result, black traps collected the largest number of Ae. albopictus as a mean 0.7 of 1.0 for Mosquito Preference Index (MPI), followed closely by red, blue, and purple (MPIs, 0.6) that were significantly higher (p<0.05) than those of green (MPI, 0.5), white (MPI, 0.3), and yellow (MPI, 0.2). Similarly, the MPIs for Cx. pipiens were significantly higher at black and red traps (MPIs, 0.7) but the MPIs (0.3) at white and yellow traps were significantly lower than those of the other colors.
        256.
        2018.10 구독 인증기관·개인회원 무료
        Tomato yellow leaf curl virus (TYLCV) and its vector insect, the sweet potato whitefly Bemisia tabaci, are major threats to tomato and pepper production in all around world. Since the last three decades, both B. tabaci and TYLCV have been invaded into many countries via different routes. Our studies showed that various geminiviruses including TYLCV can be transmissible by seeds as well as whiteflies. Furthermore, commercially developed resistant tomato strains against TYLCV infection can serve as TYLCV reservoirs and potentially influence on TYLCV epidemics. Therefore, transmission pathways through both insect vectors and seeds should be concerned for suitable management of geminiviruses and whiteflies.
        258.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기존에 재배된 바 없었던 암대극을 새로운 관상식물로 개발하고자, 절화 특성 평가를 실시하였다. 2017년 3월과 4월, 제주도에 자생하고 있는 암대극을 채취한 후, 수분흡수, 절화수명, 노화 과정 등 절화수명 특성을 평가하였다. 또한 sucrose 농도, 절화길이, pH 농도, 저장온도에 따른 절화 특성을 조사하였다. 본 실험은 국립수목원 유용식물증식센터의 Phyto-garden system(12h photoperiod, 25℃, 70% RH)과 실온(23℃, 44% RH)에서 수행하였고 2~3일 간격으로 수분흡수량, 생체중, 절화수명을 측정하였다. 실험 환경에 따른 연구에서 실온(14.4일) 보다 phyto-garden system(42.4일)의 절화 수명이 약 3배 더 길었고, 절화길이에 따른 연구에서는 절화수명이 20cm, 15.2일, 40cm, 17.4일로 나타났다. Sucrose 농도에 따른 연구에서는 처리에 따른 절화수명 증진 효과는 없었고, pH에 따른 연구의 절화수명은 pH 5, 15.6일, pH 6, 13.4일, pH 7, 13.1일, 증류수, 14.8일이었다. 저장온도에 따른 실험에서, 절화수명은 4℃, 83일, 10℃, 41.2일, 15℃, 35.5 일, 20℃, 17.4일, 실온, 14.4일이었는데, 온도가 감소할수록 절화수명이 길어짐을 알 수 있었다. 결론적으로, 암대극은 비교적 광도와 습도가 높은 환경과 절화길이가 길고 저장온도가 낮을수록 수명이 오래 유지되는 것을 알 수 있었다.
        4,000원
        259.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        암대극(Euphorbia jolkinii Boiss.)은 우리나라 제주도 및 남부 해안가 암석지에서 자생하는 대극과(Euphorbiaceae)의 다년생 초본식물이다. 등잔모양꽃차례가 황록색으로 3월부터 5월까지 긴 기간 동안 개화하기 때문에 새로운 관상식물로 개발할 가치가 높다. 본 연구에서는 암대극을 재배화하고자 우선적으로 제주도의 자생지 환경과 개체군 분포 특성을 조사하였다. 제주도 전역의 해안을 따라서 암대극 개체의 전수조사를 실시한 결과 40여 지점에 걸쳐 약 14,817개체가 자생하는 것으로 확인되었다. 그 중 제주도 본섬의 동쪽에 위치한 우도에 1,075개체(전체의 7.3%), 북서쪽에 위치한 비양도에 952개체(6.4%), 남쪽에 위치한 가파도에 589개체(4.0%)가 조사되었다. 암대극은 주로 제주도 본섬 남동부 해안가 암석지대에 집중적으로 자생하는 것으로 확인되었고 가파도, 우도, 비양도의 경우에도 섬 동쪽지역에만 분포되어 있었다. 암대극의 생육은 자생지에 따라 차이가 있었다. 초장, 줄기 길이, 줄기 직경은 꽃 크기와 정의 상관관계를 보였다. 모든 지역에서 꽃이 피는 시기는 3월 말로 비슷하게 개화가 시작되었고, 6월 초에는 대부분의 꽃에서 종자가 성숙하여 탈리되었다. 암대극의 주변 식생은 갯개미자리, 돌가시나무, 순비기나무, 갯강활 등 30여 종이 분포되어 있었고, 초본이 80%를 차지하는 데에 반해, 목본은 20%로서 초본식물이 주를 이루었다. 토양의 pH는 8.3~9.4의 범위에 있었으며, 염분 농도는 0.003~0.017%로 나타났다. 유기물 함량은 중문에서 1.9%, 가파도에서 1.4%, 표선면에서 1.0%로 나타났고, CEC는 가파도에서 10.7cmol+/kg, 표선면에서 5.6cmol+/kg, 중문 지역에서 1.3cmol+/kg로 나타났다. 전기전도도는 중문, 가파도, 표선면에서 각각 0.47dS/m, 0.19dS/m, 0.16dS/m으로 나타났고, Cl-은 57.45mg/kg, 63.01mg/kg, 8.12mg/kg으로 나타났다. 중문에서 유효인산은 검출되지 않았다.
        4,000원
        260.
        2018.07 구독 인증기관·개인회원 무료
        This research provides empirical support to the understanding of the consumers’ public self-consciousness and its impact on the luxury brand attachment. A self-administered survey questionnaire was distributed to an online consumer panel in Australia. The results show that both actual and ideal self-congruity positively influence the consumers’ luxury brand attachment. The impact of actual self-congruence on luxury brand attachment is stronger than that of the ideal self-congruence for privately consumed luxury products. The impact is non-significant for publicly consumed luxury products. Moreover, highly attached consumers tend to advocate the luxury brands to other consumers. The research also reveals that public self-consciousness does not moderate the relationship between consumers’ perceived self-congruence and luxury brand attachment. The results suggest that luxury brand advertisers should incorporate the consumers’ actual and ideal self into the advertising message to strengthen the attachment. Future research may validate the hypothesised relationships within different luxury product and service category to enhance the generalisability of the findings.