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        검색결과 78

        62.
        1993.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼멸구 생태형 1, 2, 3의 형태의 차이를 구별하고자 장시형과 단시형 암수를 대상으로 형태적 변화를 관찰하였다. 암컷은 생식 부위인 Abdominal lateral lobes의 좌우 부위를 비교 조사하였다. 수컷은 앞다리, 가운데 다리, 뒷다리 부절의 Unguitractor plate를 조사하였다. 생태형 2의 단시형 암컷은 Abdominal lateral lobes의 기부가 잘라진 것으로 생태형 1과 3보다 많았다. Unguitractor plate의 경우 생태형 2는 장단시형 암 수 모두 부절 안쪽으로 함입되어 있었다.
        4,000원
        63.
        1993.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라에 발생하고 있는 벼멸구 생태형의 형태적 차이를 구명하고자 생태형 1, 2, 3의 단시형 암컷과 숫컷의 다리부분의 형태를 관찰하였다. 앞다리, 가운데 다리 그리고 뒷다리의 제3부절의 형태를 51개 부위에서 조사한 다음 통계학적 분석을 위하여 정준 판별 분석법을 도입하였다. 각 생태형간의 Mahalanobis distance는 숫컷의 경우 생태형 2와 3 사이에서 가장 짧았고, 암컷은 생태형 1과 2 사이에서 가장 길었다. Scatter plot diagram상에서 각 생태 형간 분리현상이 뚜렷하여 중심점이 각각 다르게 나타났고 각 생태형에 속하는 개체는 중심점 부근에 고르게 분포하였다. 각 생태형간의 Group membership 조사에서 암수 모두 각 생태형은 각각 동일한 생텨형을 분류되었다.
        4,000원
        64.
        2013.07 서비스 종료(열람 제한)
        We investigated whether sound could alter gene expression in plants. Using a sound-treated subtractive library, a set of sound-responsive genes in plants was demonstrated through mRNA expression analyses. Of them, the rbcS and ald genes, which are light responsive, up-regulated their expression with sound treatment in both light and in dark conditions. This suggested that sound could be used as a gene regulator instead of light. When we analyzed ald gene expression using various single wavelengths, a significant increase in mRNA levels was found at 125 or 250 Hz but decreased at 50 Hz, indicating that the gene responded to sound in a wavelength-specific manner. To determine whether the ald promoter respond to sound, we generated transgenic rice plants harboring the chimeric gene consisting of a 1,506-bp promoter fragment of the ald gene fused to Escherichia coli GUS reporter gene. Analyses of mRNA expressison level of three independent transgenic lines sound-treated with 50 or 250 Hz for 4 h showed that the Gus gene expression in all three transgenic lines was up regulated by 250 Hz, but down regulated by 50 Hz. These results correlated with sound responsive mRNA expression pattern observed for the ald gene in rice plants, indicating that the 1,506-bp ald promoter confers sound-responsiveness on a reporter gene in transgenic rice plants. We also investigated whether sound waves could improve salt tolerance in rice seedling. The rice seedlings were sound treated with 800 Hz for 1hr, and then treated with 0, 75, 150, and 225mM NaCl for 3 days to observe changes in physiological and morphological aspects. Sound treatment seedlings resulted in enhanced salt stress tolerance, mainly demonstrated by the sound treated seedlings exhibiting of increased root relative water contents (RWC), root length and weight, photochemical efficiency (ratio of variable to maximum fluorescence, Fv/Fm), and germination rate under salt stress condition. This demonstrates that a specific sound wave might be used, not only to alter gene expression in plant, but also to improve salt stress tolerance.
        66.
        2011.09 서비스 종료(열람 제한)
        The development of humanized culture system of human embryonic stem cells (hESCs) hold promise for therapeutic applications. However, conventional culture system contain animal-derived components such as fetal bovine serum and mouse embryonic fibroblasts that bear a risk of transmitting non-human pathogens and incorporation of non-human immunogenic molecules to hESCs. In this study, we developed an efficient xeno-free hESCs culture system using humanized materials, the CELLstartTM, human foreskin feeder and xeno-free medium containing knockOutTM SR XenoFree (XF-medium) without animal-derived material. The hESCs were gradually adapted to the XF-medium; 25:75, 50:50, 75:25 and 100:0. Two karyotypically normal hESC lines, SNUhES4 and H1, were used for the experiments of xeno-free culture condition. The attachment rates at xeno-free culture system were 52.6±12.4%, 67.0±16.6%, 59.0±13.9%, 28.3±2.9% in SNUhES4, 79.3±5.4%, 53.8±20.9%, 69.4 ±6.4%, 59.8±12.6% in H1 and the spontaneous differentiation rates were 42.2±12.7%, 31.4±2.9%, 40.8±14.5%, 55.2±35.5% in SNUhES4, 35.6±8.5%, 36.4±13.5%, 48.4±7.8%, 80.1±6.0% in H1 in the first four passage. Although the attachment rates were low and the spontaneous differentiation rates were high compared to that of conventional system in the early passages using this humanized culture condition, hESCs in this culture condition were found to maintain hESC characterizations; morphology, expression of cell surface markers and stable karyotype. Our results indicate that simplified compositions of humanized culture system can be applicable to the further optimization for a xeno-free culture of hESCs without the loss of pluripotency and contamination from xenogenic sources.
        69.
        2006.11 KCI 등재 서비스 종료(열람 제한)
        The present study was initiated to explore the yield potential of bushbean by exploiting the interaction of variety, sowing time, and fertilizers containing N, P, and K Two varieties namely BARI Bushbean 1 and BARI Bushbean 2, three levels of fertilizer viz. control (N0P0K0 ), medium (N20P30K30 ), high (N40P60K60 ) and three sowing times (November 15, December 1 and December 15) were considered as treatment variables. Among the varieties, BARI Bushbean 2 always showed better performance for most of the yield and yield attributes duly attributed by the application of fertilizers ~circleda N: P: K = 40: 60: 60 respectively. The highest seed yield (1375.17 kg/ha) was recorded when the crop was sown on the 15th November with the supplemented soil nutrition status as above. The influence of sowing times indicate that there is a gradual trend of decreasing in seed yield and other associated parameters after first sowing (15th~;November ). The results of this study suggest that the multi-locational trial under varied sowing times with soil nutrition might potentially increase the long-term adaptation of bushbean in Bangladesh.
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