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        검색결과 174

        121.
        2017.08 서비스 종료(열람 제한)
        Ascidian embryos have become an important model for embryological studies, offering a simple example for mechanisms of cytoplasmic components segregation. It is a well-known example that segregation of mitochondria into muscle lineage cells occurs during ascidian embryogenesis. It is, however, still unclear what signaling and molecular event control polarized distribution of mitochondria in the early ascidian embryonic development. To obtain molecular markers for studying mechanisms involved in polarized distribution of mitochondria, we have produced monoclonal antibodies, Mito-1, Mito-2 and Mito-3, that specifically recognize mitochondria-rich cytoplasm in all cells of the ascidian Halocynthia roretzi embryos. These antibodies stained cytoplasm like a mesh structure in epidermis cells, except for nuclei, at the early tailbud stage. Similar pattern was observed in vital staining of mitochondria with DiOC2, a fluorescent probe of mitochondria. These antibodies showed that mitochondria were distributed evenly in the animal hemisphere blastomeres at cleavage stages, whereas did not in the vegetal hemisphere blastomeres. Mitochondria were transferred more into cells of the marginal zone, such as muscle and nerve cord lineage cells, than into cells of the central zone, such as mesenchyme, notochord and endoderm lineage, in the vegetal hemisphere. Therefore, it is suggested that these antibodies may be useful as markers for analysing mechanisms involved in polarized distribution of mitochondria during ascidian embryogenesis.
        122.
        2017.08 서비스 종료(열람 제한)
        Asymmetric cell divisions play crucial roles during ascidian embryogenesis. In these processes, an FGF signaling is an essential inductive signal for establishing cell fate polarization, such as mesenchyme and notochord. It was well reported that the FGF signaling cascade is composed of FGF, FGF receptor, Ras, MEK, Erk and Ets. However, mechanisms of communication between the FGF and other signaling pathways and of integrated regulation of signaling pathways have remained largely unknown. In this study, we isolated HrS6K, a homologue of the S6K gene that belongs to the S6-H1 kinase of the ribosomal S6 kinase family, and HrNck1, a homologue of Nck1 gene that encodes an adaptor protein containing Src homology 2 and 3 domains, from the ascidian Halocynthia roretzi, to elucidate the mechanisms. Zygotic expression of HrS6K was initiated as early as the 16-cell stage. In the 64-cell stage embryos, expression of HrS6K was seen in mesenchyme precursor cells. The signal was detected in dorsal midline cells and mesenchyme clusters of the early tailbud embryos, and then down-regulated by the late tailbud stage. In adults, HrS6K mRNA was highly detected in muscle and stomach by QPCR method. On the other hand, HrNck1 transcripts are detected maternally. Zygotic HrNck1 mRNA was strongly expressed in mesenchyme clusters of the neurula, and in tail tip cells of the early tailbud embryos. These results suggest that HrS6K and HrNck1 are involved in formation of mesenchyme cells, which are specified by the FGF signaling.
        123.
        2017.08 서비스 종료(열람 제한)
        The formation of definitive endoderm (DE) is a fundamental step for the development of the gastrointestinal tract, respiratory tract and endocrine organs. We present a CRISPR-based pooled screening approach to identify genes which contribute to DE induction from hiPSCs in vitro. CRISPR-based pooled genetic screens in mammalian cell culture enable researchers to identify genes required for a cellular phenotype of interest in an unbiased way. To enable a CRISPR-based forward genetic screen for identifying regulatory genes required for DE differentiation from hiPSCs, we performed pooled screens using a human genome-scale CRISPR knockout library. In addition, we performed a transcriptional activation screen using a lentiviral CRISPRa library to identify the downstream targets of the TGF/nodal/activin signaling pathway, which is a key signaling pathway for DE specification. We identified several signaling pathways including TGFβ, Erk, JNK, and CREB pathways are involved with DE differentiation. We suggest that CRISPR-based pooled genetic screens are a useful tool to identify key signaling pathways and genes required for in vitro differentiation processes and are served as a platform to improve differentiation protocols.
        124.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to find a rapid determination of the hot air stress in maize (Zea mays L.) leaves using a portable chlorophyll fluorescence imaging instrument. To assess the photosynthetic activity of maize leaves, an imaging analysis of the photochemical responses of maize was performed with chlorophyll fluorescence camera. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlorophyll a fluorescence. Chlorophyll a fluorescence imaging (CFI) method showed that a rapid decrease in maximum fluorescence intensity (Fm) of leaf occurred under hot air stress. Although no change was observed in the maximum quantum yield (Fv/Fm) of the hot air stressed maize leaves, the other photochemical parameters such as maximum fluorescence intensity (Fm) and Maximum fluorescence value (Fp) were relatively lowered after hot air stress. In hot air stressed maize leaves, an increase was observed in the nonphotoquenching (NPQ) and decrease in the effective quantum yield of photochemical energy conversion in photosystem II (Φ PSII). Thus, NPQ and ΦPSII were available to be determined non-destructively in maize leaves under hot air stress. Our results clearly indicated that the hot air could be a source of stress in maize leaves. Thus, the CFI analysis along with its related parameters can be used as a rapid indicating technique for the determining hot air stress in plants.
        125.
        2016.10 서비스 종료(열람 제한)
        Background : This study for the stable production and supply of seeds of Angelica gigas Nakai(Man-chu Korean Angelica), when seeds harvested using nets, seed productivity was investigated. Methods and Results : Planting density is 50 × 25cm, Fertilizer per 10a was sprayed amount of N-P2O5-K2O = 16-17-10kg. And the amount of compost per 10a was sprayed 3000kg. Seed harvesting nets were used for a time formed the endosperm of the seeds (later in mid-August to late). And net for seed production was used for onion nets (at least 13 × 18cm). Shoot growth conditions were as follows. Bolting rate was 89.0% in the untreated, the treated group was 93.1%. The length and thickness of each stem was 129.3 ~ 130.8cm, 1.8cm. The number of nodes per plant was 6.7 ~ 7.5 pieces, and the number of petiole was 14.8 ~ 15.5 per plant. The number of umbel was 10.3 ~ 11.1 piece per plant, and number of deleted umbel was 7.1 ~ 7.2 piece. Seed weight per plant was 24.2g of the net treatment, but ripening seeds 19.6g, 1000 grain weight were all treated and untreated 2.8g. The total seed weight per plant, the net treated was 24.2g, was the weight of the ripening seeds 19.6g. The weight of the ripening seeds were heavier than those of the control. However, the weight of 1000 grain were both treated and untreated 2.8g. When treated nets, the total seed yield per 10a was 88.0kg production, increased by 60.9% compared to untreated. In addition, the ripening seed production per 10a was 71.5kg production, increased by 50.1% compared to untreated. Researching after germination Seed Production, germination rate was 50.8% in the control group and the treatment group was 54.9%. When applying the germination rate, high-quality seed production per 10a was able to produce 39.2kg, compared to control obtain the results increased by 65%. Conclusion : Through the above results, When producing angelica seed, use of net for seed production is thought to be used as a way to prevent early shattering and insect damage.(True bug, etc.).
        126.
        2016.05 서비스 종료(열람 제한)
        Background : Indigenous plant in Jeju island, Sasa quelpaertensis Nakai, belongs to the Bambusoideae and inhabit around Mt. Halla. According to the ancient book such as Dongui Bogam, Sasa quelpaertensis Nakai have been known to possess the antidiabetic, anti-inflammatory, and anti-diuresis effect. However, because of gradual upturning temperature, Sasa quelpaertensis Nakai was spread out to wider area and intrude the habitat that other plant species are growing. Recently, although the study to seek effective use of Sasa quelpaertensis Nakai, the investigation about functional properties has not been taken place enough. Methods and Results : To assess the inhibitory activity of melanin synthesis, we employ the tyrosine as substrate and measure the formation of dopaquione at 490 nm. Firstly, 0.1 mM potassium phosphate buffer and tyrosinase were mixed and incubated at 37℃. After incubating at 37℃, the absorbance rate was measured at 490 nm. The value was compared with positive control, arbutin, and calculated with the rate between sample and control value. Previously, formononetin, glabrene, glabridin, glabrol, artocarbene, dihydromoriin are known as effective substances for whitening. Moreover, the arbutin, which was separated from Arctostaphylos uva-ursi (L.) Sprengel, are widely used in cosmetic field. Arbutin inhibits tyrosinase and tyrosine synthesis, which induce blackish pigmentation. Practically, the Sasa quelpaertensis Nakai leaf ethanol extract depend on different solvent condition, whole extracts showed stronger inhibition than arbutin. Especially, 60% ethanol extract exhibited twice higher tyrosinase inhibitory activity than arbutin, whereas least inhibitory activity was seen in 20% ethanol extract. Conclusion : In this study, a attempt was made to investigate the tyrosinase inhibitory activity of Sasa quelpaertensis Nakai leaves extracted by different solvent condition. In the results, each extracts was prior to arbutin. Yet, 20% ethanol extract was lowest, but on the one hand, 60% ethanol extract demonstrated the highest tyrosinase inhibitory activity.
        127.
        2013.12 서비스 종료(열람 제한)
        Retroperitoneal liposarcoma is an infrequent malignancy in adulthood arising from mesenchymal tissues. It is often diagnosed when the tumor becomes too large, suppressing adjacent organs and causing symptoms. We report on a case of giant liposarcoma found in a 77-year-old female undergoing surgical resection.
        128.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Plant biomass is a huge carbon-complex that has potential as a nutrient. Therefore we extracted and separated useful materials for plant growth from tea leaf and stem. The pre-treatment process including high temperature (200 °C) and pressure (20-40 kgf/cm2) was treated for several minutes and extracted at 120 °C for 30-60 minutes. After that the chemical compositions and ingredients were analyzed from that plantnutrient. As a result of mineral contents, calcium and magnesium concentrations are higher than other minerals. Also the result of carbohydrates analyses has shown that the sugar oligomer consists of xylose(95.3%) and glucose(4.7%), and the sugar monomer consists in the order of xylose (52.7%) > manose (22.8%) > arabinose (10.8%) > galactose (10.2%) > glucose (3.5%). Before applied to field, in vitro plant growth system and formulation were examined. To evaluate the effect of the nutrients, both strawberry green-house and persimmon fields were used in this test. The treated persimmons were heavier than controls scored at 13-22%. In addition, the storageperiod was extended in the treated strawberries. Interestingly in the treated strawberry, the contents of polyphenols were increased (38-57%). These results suggest that the plant-nutrient can afford to help for plant growth and storage, and it can be substituted for other commercial nutrients. In conclusion, this plant-nutrient may help to extend eco-friendly or organic farming in Hadong-gun area.
        134.
        2011.08 KCI 등재 서비스 종료(열람 제한)
        We investigated the effects of temperature changes on the oxygen consumption rhythm in Japanese eels, Anguilla japonica, using an automatic intermittent flow respirometer (AIFR). The endogenous rhythm of the oxygen consumption rate (OCR) in the eels (n = 18; 44-74 cm, 145-690 g), freshly collected by bag net from estuaries, was nearly synchronous with the tidal pattern of the estuarine collection site. The magnitude of mean OCR (mOCR) of eels showed variable range of 82.2 - 116.5 ml O2 kg-1 ww h-1 under constant conditions. In case of increasing temperature from 25 to 38℃, the OCR of eels exhibited a gradually increasing trend with a rhythmic pattern until 36℃. Above 36℃, the rhythms of the OCR dampened and the OCR decreased rapidly at around 36 - 37℃. The OCR of the eels exhibited the maximum value at 38℃, and then it sharply decreased. The results suggested that the critical thermal maximum (CTM) regarding the endogenous rhythms of the eels was at around 36 - 37℃ when water temperature increased at 0.5℃/14 h following the acclimation at 25℃. In case of decreasing temperature (0.5℃/14 h) from 25 to 0℃, the OCR of the eels displayed a abrupt decrease up to 23℃, and between at 23 and 20℃, there was an agitation which showed a slight increase in the OCR with a duration of 1-2 days. Below 9℃, the OCR rhythm of the eels showed a constant state regardless of temperature decreasing. These results suggest that the Japanese eel has an upper incipient lethal temperature at 36℃, with a lower thermal limit at 9℃. The biochemical aspects of the eels influenced by water temperature need to be further studied.
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