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        검색결과 41

        21.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.
        4,000원
        23.
        2017.12 서비스 종료(열람 제한)
        Acute myocardial infarction (AMI) as an acute form and a catastrophic manifestation of coronary artery disease (CAD) is the major cause of morbidity and mortality worldwide. The prevalence and incidence of myocardial infarction can be influenced by demographic, biological and psychosocial factors, and it is rare in childhood and adolescent years. Contrary to the elderly, where cardiac attack is mainly caused by CAD, exercise-induced cardiac attack is relatively more prevalent in a young adult. We report here on a case of ST-segment elevation myocardial infarction (STEMI) in a young adult during vigorous physical activity and we review the relevant literatures.
        24.
        2017.06 KCI 등재 서비스 종료(열람 제한)
        The influence of triploidization on histological characteristics of retina, trunk kidney, liver and midgut tissue, and cell cycle of tail fin and gill tissue in far eastern catfish, Silurus asotus were analyzed. In the infertile triploid fish, the nucleus and/or cell size of secondary proximal tubule cells of trunk kidney, hepatocyte and midgut epithelium are much larger than those of the corresponding cells in the diploid fish (P<0.05). However, triploid tissue showed fewer number of outer nuclear layer in retina and nuclei in secondary proximal tubule of trunk kidney than those for diploid tissue. The mean percentages of the Gl-, the S- and the G2+M-phase fractions were 92.5%, 3.2% and 4.3% in tail fin tissue of diploid, and 93.4%, 2.6% and 4.0% in those of triploid, respectively. There were no significant differences in the percentages of each cell cycle fraction between diploid and triploid. The mean percentages of each phase fractions were 75.1%, 11.1% and 13.8% in gill tissue of diploid and 85.2%, 8.9% and 5.9% in those of triploid, respectively. The differences of cell cycle between tail fin tissue and gill tissue were statistically significant in diploid and triploid (P<0.05). Also, the differences between diploid and triploid were statistically significant in tail fin tissue and gill tissue (P<0.05). Cyclin D1 and cyclin E expressions were not significantly difference between gill tissue and tail fin tissue, and protein expressions of induced triploid were higher than those of diploid. Results from this study suggest that some characteristics in the triploid exhibiting larger cell and nucleus size with fewer number of cell than diploid can be used as an indicator in the identification of triploidization and ploidy level in far eastern catfish.
        25.
        2017.06 KCI 등재 서비스 종료(열람 제한)
        The influence of triploidization on histological characteristics of retina, trunk kidney, liver and midgut tissue, and cell cycle of tail fin and gill tissue in far eastern catfish, Silurus asotus were analyzed. In the infertile triploid fish, the nucleus and/or cell size of secondary proximal tubule cells of trunk kidney, hepatocyte and midgut epithelium are much larger than those of the corresponding cells in the diploid fish (P<0.05). However, triploid tissue showed fewer number of outer nuclear layer in retina and nuclei in secondary proximal tubule of trunk kidney than those for diploid tissue. The mean percentages of the Gl-, the S- and the G2+M-phase fractions were 92.5%, 3.2% and 4.3% in tail fin tissue of diploid, and 93.4%, 2.6% and 4.0% in those of triploid, respectively. There were no significant differences in the percentages of each cell cycle fraction between diploid and triploid. The mean percentages of each phase fractions were 75.1%, 11.1% and 13.8% in gill tissue of diploid and 85.2%, 8.9% and 5.9% in those of triploid, respectively. The differences of cell cycle between tail fin tissue and gill tissue were statistically significant in diploid and triploid (P<0.05). Also, the differences between diploid and triploid were statistically significant in tail fin tissue and gill tissue (P<0.05). Cyclin D1 and cyclin E expressions were not significantly difference between gill tissue and tail fin tissue, and protein expressions of induced triploid were higher than those of diploid. Results from this study suggest that some characteristics in the triploid exhibiting larger cell and nucleus size with fewer number of cell than diploid can be used as an indicator in the identification of triploidization and ploidy level in far eastern catfish.
        26.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Sexual dimorphism is the most conspicuous difference between the sexes. This study examines possible sexual dimorphism and the relative growth patterns of morphometric characteristics in the marine medaka, Oryzias dancena for their potential to help differentiate between males and females of this species. The von Bertalanffy growth parameters estimated by a non-linear regression method were L∞=30.2 mm, K=3.22/year, and τ0=-0.05. All 18 characteristics measured showed a difference between males and females from 70 days after hatching. Each of these characteristics were significantly different between sexes (ANCOVA, P<0.05), and the ratio of standard length between sexes showed that males were larger than females for all five morphometric measurements. Fin length measurements were taken for 21 distances of anal fin and 7 distances of dorsal fin between landmarks. There were all differences for all dorsal fin rays between the males and the females and there is significant difference in 70 days after their hatch when the sexual dimorphism is presented. The significant difference (P<0.05) in fin ray for male and female was more greatly seen as they grow. Male marine medaka showed more rapid growth than females, with longer length, dorsal fins and anal fins. Differences in these characteristics will be useful during experiments when it is necessary to differentiate between sexes of marine medaka.
        27.
        2016.10 서비스 종료(열람 제한)
        Background : This study was carried out to distribute superior cultivars to farmers by analyzing growth characteristics of ginseng and effectively set the target for breeding by investigating annual agronomic characteristics of ginseng. Methods and Results : As a plant materials, Chunpoong (CP), Yunpoong (YP), Gopoong(GP), Gumpoong (GU) and Sunun (SU) were transplanted in Eumseong (ES), Geumsan (GS) and Yeoncheon (YC) on March 2013. Cultivation and management were conducted on the basis of the standard guidelines. According to stem and petiole by region, YC represent the largest stem diameter, leaf length and petiole length of cultivars, followed by those in ES and those in GS. Leaf growth of cultivars was overall the best in YC. Although CP had long and narrow leaves in all regions, YP and SU had short and narrow leaves. Root weight of all cultivars was the best in YC, but there was no significant differences by them. Growth of CP, YP and GP was generally good in ES. Growth of cultivars was relatively even in GS, but it was poor compared to cultivars which were cultivated in ES and YC. Conclusion : There were considerable differences in root growth of cultivars. However, this results suggest that CP of 4-year-old is produced stably in some regions because it had a small coefficient of variation.
        28.
        2016.10 서비스 종료(열람 제한)
        Background : This study was performed to investigate by antioxidant activity, total phenolic contents, total flavonoid contents, and effective component of Astragalus membranaceus treated with different artificial light Sources (fluorescent lamp, red, blue, green, white, LEP). Methods and Results : We investigated the effects of various artificial light sources on the DPPH radical activity, total phenol and flavonoid contents, tyrosinase activity and main flavonoid compounds contents (formononetin and calycosin) and other biological activities in A. membranaceus. Antioxidant activities were 53.6% as the highest level of activity under LEP light. Growth under LEP light also produced the highest total phenolic and flavonoid contents of 36.05 and 5.94 mg/ml, respectively. Extracts from plants grown under LEP light caused the highest inhibition of tyrosinase activity with inhibition of 35.37, 61.87, and 65.49%, respectively, for extract concentrations of 100 μg/ml, 500 μg/ml, and 1000 μg/ml compared with other artificial light treatments. Conclusion : Little information is available on the influence of LED and LEP light sources on antioxidant production or other biological activities in A. membranaceus. Our goal in this study was to determine the effects of LED and LEP artificial light sources on the production of new functional compounds in A. membranaceus.
        29.
        2016.05 서비스 종료(열람 제한)
        Background : Recently, there is a urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. In order to develop ginseng varieties with such traits, systematic breeding program and comprehensive field studies are prerequisite. Methods and Results : ‘Cheonmyeong' seeds were collected in 2008 from the farmer field of Buyeo. Physiological investigation and propagation were conducted from 2009 to 2011. It was given the name 'Eumseong No. 8 through the observed yield trial from 2012 to 2013 and local adaptability was carried out from 2014 to 2015. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. Yellow-red leaf and pink berry at maturing stage were observed. The time of emergence, flowering and berry maturity of the ‘Cheonmyeong’ were faster than those of ‘Chunpoong’. Stem length of ‘Cheonmyeong’ was shorter than that of ‘Chunpoong’, whereas stem diameter was thicker than that of ‘Chunpoong’. Main root length was shorter but main root diameter is thicker than that of ‘Chunpoong’. Number of seeds of ‘Cheonmyeong’ was fewer than that of ‘Chunpoong’ but 1,000-seeds weight and stratification rate were higher than those of ‘Chunpoong’. The yield performance of this variety was 661 kg/10 a in local adaptability test for two years, which is 22% higher than that of ‘Chunpoong’. ‘Cheonmyeong’ showed strong resistance to phytophthora blight, mulberry mealybug and nematode and moderate resistance to alternaria blight. ‘Cheonmyeong’ did almost not occur yellow spot of aerial part and rusty skin of root, show moderate resistance at high temperatures. Conclusion : Our study demonstrated that ‘Cheonmyeong’ is an ideal variety with heavier root weight and enhanced stress resistance and contribute will enhance biotic/abiotic stress resistance and increase the farmers' income.
        30.
        2016.05 서비스 종료(열람 제한)
        Background : The effect of ridge-up bed cultivation and stem training method on the plant growth and yield of Cynanachum willfordii was investigated. Methods and Results : Domestic variety of Cynanachum willfordii was tested at Chungbuk ARES under the following conditions. Nonsupporting (custom) and I-form supporting was used for stem training method, and ridge height was set as 30 (custom) and 60 cm (high ridge). Planting spacing was adjusted to 30 (interrow spacing) × 20 cm (intrarow spacing), and other major management was followed the method of standard cultivation for medicinal crop. Investigated result from leaf characteristics, leaf length was longer in high ridge cultivation (HRC) as 11.1 cm than custom cultivation (CC) as 10.6 cm. Leaf width is proved to be 12.8 (HRC) > 11.2 cm (CC). Leaf number is proved to be 294 (HRC) > 254/plant (CC), with higher number of 44/plant at HRC and weight/10 leaves were more heavy at HRC (4.9 g) than that of CC (2.6 g). It was more fruit setting at HRC over 15/plant. According to the stem training method and ridge height from nonsupporting cultivation, main root was 4.0 (CC), higher than that of HRC over 0.5/plant. However, root length was more longer in HRC (28.6) than that of CC (25.0 cm). Main root diameter was also showed more thicker pattern in HRC. From staking cultivation, root number of HRC was 7/plant, it was recorded more 3/plant than that of CC, and it was also same pattern in main root length and root diameter. By the standard of commercial root, yield of living roots in nonsupporting cultivation were 59.0g/plant (HRC), it was more heavy over 10.4g/plant than that of CC. In staking cultivation, HRC were recorded as 74.2g/plant, more heavy 6.9g/plant than that of CC. Yield from I-form support stem training and ridge-up bed cultivation of HRC was higher approxmiately 52.7% than that of CC. Conclusion : Overall growth by high ridge cultivation of I-form support was good and yield of HRC was also increased over 52.7% than that of CC.
        31.
        2014.07 서비스 종료(열람 제한)
        Genome sequencing researches for considerable numbers of crops and wild plants are being developed. Cytogenetic researches according to chromosome number and size are essential to confirm and comprehend ploidy level and genome size before genome sequencing project is actually conducted. Cytogenetic researches on six food crop plants were carried out by DAPI staining and fluorescence in situ hybridization (FISH) method. Fagopyrum esculentum Moench showed 2n=2x=16, each chromosome length of 1.42㎛ to 1.77㎛, total chromosome length of 13.31㎛, and karyotypic formula of 2n=8m; Phaseolus angularis W.F. Wight, 2n=2x=22, 2.01㎛ to 3.84㎛, total 28.03㎛, 2n=9m+2sm, Perilla frutescens var. japonica Hara, 2n=2x=40, 1.73㎛ to 2.76㎛, total 44.36㎛, 2n=5m+13sm+2st. Chromosome sizes of the other three species such as, Panicum miliaceum L., 2n=2x=36, total chromosome length of 30.83㎛, Sesamum indicum L., 2n=2x=26, 27.39㎛, lpomoea batatas L., 2n=2x=30, total 33.51㎛ were too small for each chromosome type to be identified and analyzed. The result of FISH analysis using 5S and 45S rDNA probe showed species-specific chromosome locations in the genome. These preliminary analyses were carried out to decide which food crop to prioritize for genome sequencing. This work was supported by the “Cooperative Research Program for Agriculture Science & Technology Development (No.PJ009837), Rural Development Administration, Republic of Korea.
        32.
        2014.07 서비스 종료(열람 제한)
        Mungbean (Vigna radiata) is a fast-growing, warm-season legume crop that is primarily cultivated in developing countries of Asia. We constructed a draft genome sequence of mungbean to facilitate genome research into the subgenus Ceratotropis and to enable a better understanding of the evolution of leguminous species. The draft genome sequence covers 80% of the estimated genome, of which 50.1% consists of repetitive sequences. In total, 22,427 high confidence protein-coding genes were predicted. Based on the de novo assembly of additional wild mungbean species, the divergence of what was eventually domesticated and the sampled wild mungbean species appears to have predated domestication. Moreover, the de novo assembly of a tetraploid Vigna species (Vigna reflexo-pilosa var. glabra) provided genomic evidence of a recent allopolyploid event. To further study speciation, we compared de novo RNA-seq assemblies of 22 accessions of 18 Vigna species and protein sets of Glycine max and Cajanus cajan. The species tree was constructed by a Bayesian Markov chain Monte Carlo method using highly confident orthologs shared by all 24 accessions. The present assembly of V. radiata var. radiata will facilitate genome research and accelerate molecular breeding of the subgenus Ceratotropis.
        33.
        2013.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Tissue equivalent proportional counter (TEPC) can measure the Linear Energy Transfer (LET) spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS). The prototype TEPC which can simulate a 2 μm of the site diameter for micro-dosimetry has been tested with a standard alpha source (241Am, 5.5 MeV). Also, the calibration of the TEPC was performed by the 252Cf neutron standard source in Korea Research Institute of Standards and Science (KRISS). The determined calibration factor was kf = 3.59×10-7 mSv/R.
        34.
        2012.07 서비스 종료(열람 제한)
        R genes are a key component of genetic interactions between plants and biotrophic bacteria and are known to regulate resistance against bacterial invasion. The most common R proteins contain a nucleotide-binding site and a leucine-rich repeat (NBS-LRR) domain. Some soybean NBS-LRR genes have also been reported to function in disease resistance. A total of 319 genes were determined to be putative NBS-LRR genes in the soybean genome. The number of NBS-LRR genes on each chromosome was highly correlated with the number of disease resistance QTL in the 2-Mb flanking regions of NBS-LRR genes. In addition, the recently duplicated regions contained duplicated NBS-LRR genes and duplicated disease resistance QTL, and possessed either an uneven or even number of NBS-LRR genes on each side. The significant difference in NBS-LRR gene expression between a resistant near-isogenic line (NIL) and a susceptible NIL after inoculation of Xanthomonas axonopodis pv. glycines supports the conjecture that NBS-LRR genes have disease resistance functions in the soybean genome. The number of NBS-LRR genes and disease resistance QTL in the 2-Mb flanking regions of each chromosome was significantly correlated, and several recently duplicated regions that contain NBS-LRR genes harbored disease resistance QTL for both sides. In addition, NBS-LRR gene expression was significantly different between the BLP-resistant NIL and the BLP-susceptible NIL in response to bacterial infection. From these observations, NBS-LRR genes are suggested to contribute to disease resistance in soybean. Moreover, we propose models for how NBS-LRR genes were duplicated, and apply Ks values for each NBS-LRR gene cluster.
        38.
        2004.04 KCI 등재 서비스 종료(열람 제한)
        Molecular genetic markers have wide applicability for a various genetic analyses, and genetic mapping with PCR-based markers has identified many loci in the rice genome. This study was conducted to develop a genetic map of rice based on SSR and MITE-AFLP
        39.
        2004.02 KCI 등재 서비스 종료(열람 제한)
        New balloon flower (Platycodon grandiflorum) variety, ‘Jangbaek’, had been developed by pureline selection from some native cultivars collected in Milyang by the medicinal crops research team of the National Yeongnam Agricultural Experiment Station at 200
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