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        검색결과 53

        21.
        2011.10 구독 인증기관·개인회원 무료
        In DNA barcoding, the DNA degradation of old museum specimens has been limited full-length (658bp) sequencing. The challenges associated with the retrieval and authentication of degraded DNA extracts from fossil and old museum specimens were principally limited to analyze the relatively short sequences (<300 bp). Furthermore, almost protocols in other to analyzed the degraded DNA contained the cloning process after PCR causing the time-consuming and the rising costs. To overcome these problematic circumstances, we tried a modified method to analyze full-length of DNA barcoding region in 30~60 year-old butterfly specimens (225 samples in 28 species), using direct sequencing after PCR with species-specific overlapping primer sets per each species. As a result, all of 28 species have been successfully analyzed, although 178 samples (79%) are completely generated barcoding sequences ranged from 640 to 658 bp and 47 samples (21%) are partially sequenced ranged from 100 to 500 bp. Thus, the result showed that the direct PCR sequencing using the overlapping primer sets per species appears to have great potential efficiency for analysis of degraded DNA without incorrect sequences.
        22.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        시간분해 레이저 유도 형광 분광학을 이용하여 UO22+, UO2(OH)+, (UO2)2(OH)22+, (UO2)3(OH)5+와 같은 우라늄(VI) 화학종 규명 연구를 수행하였다. 들뜸 파장의 변화에 따른 화학종 규명 감도를 조사하였다. 266 nm의 들뜸 파장을 이용할 경우, 나노 몰 농도의 U(VI) 화합물을 구분할 수 있는 화학종 규명 감도를 얻었다. 이온 세기가 0.1 M, pH가 1인 조건에서 UO22+ 이온의 형광 스펙트럼과 형광 수명을 측정하였다. 488, 509, 533, 559 nm 파장의 특징적인 형광 봉우리를 관측하였고, 측정한 형광 수명은 1.92±0.17 ㎲ 이었다. U(VI) 가수분해 화합물의 형광 스펙트럼과 형광 수명의 변화를 이 값을 기준으로 비교하였다. 장파장 방향으로 이동한 형광 봉우리와 길어진 형광 수명을 가진 가수분해 화합물의 특징적인 양상을 보고한다.
        4,000원
        27.
        1986.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Making use of our extended version of ¨ O p i k ′ s convection theory, we have calculated magnetic cycle periods of the sun and late type stars by using Parker's dynamo theory, where we have included the non-linear effect. We presented a relationship between the computed cycle period and spectral type to analyze observed magnetic activities of the late type stars and long-term luminosity variations. It is found that (1) the stellar magentic-cycle period increases towards the later spectral type, (2) the rapid rotation facilitates the activity-related luminosity variation of stars later than about K5, (3) differential rotation plays a critical role in determining the magnetic activity-cycle period, and (4) the non-local effect should be taken into account in order to understand the observed long-term luminosity variations.
        5,100원
        28.
        1985.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A generalization of the original ¨ O p i k ′ s cellular convection theory has been made to accomodate a rotating convective medium. With the use of the formulation, a set of rotating model envelopes of the sun and late type main sequence stars have been constructed under three different rotation periods. Their thermal structures are presented and characteristics of their convection are discussed in the context of stellar dynamo. In the present study it is noted that the rotational angular velocity increases in wards with depth, and its increase turns out to be about 6% at the bottom of the solar convection zone.
        4,600원
        29.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        The green synthesis of inorganic nanoparticles (NPs) using biomaterials has garnered considerable attention in recent years because of its eco-friendly, non-toxic, simple, and low-cost nature. In this study, we synthesized NPs of noble metals, such as Ag and Au using an aqueous extract of a marine seaweed, Ecklonia cava. The formation of AgNPs and AuNPs was confirmed by the presence of surface plasmon resonance peaks in UV-Vis absorption spectra at approximately 430 and 530 nm, respectively. Various properties of the NPs were evaluated using characterization techniques, such as dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. Phytochemicals in the seaweed extract, such as phlorotannins, acted as both reducing and stabilizing agents for the growth of the NPs. The green-synthesized AgNPs and AuNPs were found to exhibit high catalytic activity for the decomposition of organic dyes, including azo dyes, methylene blue, rhodamine B, and methyl orange.
        30.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 4대강 살리기 사업 후 퇴적현상이 지배적으로 발생하는 남한강과 섬강 합류부 구간을 대상으로 2차원 수치모형인 CCHE2D 모형을 이용하여 하천의 흐름 및 하상변동에 대한 해석을 수행하였다. 대상지점 합류부는 남한강 본류의 만곡부에 지류 섬강이 유입되는 특성을 갖는다. CCHE2D 모형은 비평형 유사이송을 해석하며 소류사와 부유사 조정거리가 중요한 입력변수로 대상지점에서는 소류사 조정거리가 하상변동에 가장 큰 영향을 주는 것으로 나타났다. 수치모의 결과 유량비(Qr) 변화가 남한강과 섬강 합류부 지점에서 흐름 및 하상변동에 영향을 미쳤으며, Qr≤ 2.5인 경우에는 합류전 본류의 유속이 증가하여 흐름박리구역을 감소시켰으며 이로 인해 합류부 내측의 퇴적이 감소하였다. Qr>2.5이면 합류부 구간에 퇴적이 증가하여 사주가 형성될 가능성이 높은 것으로 나타났다. 수치모의를 통해 2013년에 발생한 유량비 변화에 의해 합류부에 고정사 주가 형성된 것을 알 수 있었다.
        31.
        2018.10 서비스 종료(열람 제한)
        Background : Light-Emitting Diodes (LEDs) have been reported to alter the composition of the secondary metabolites present in many plants. For example, light exposure has been reported to significantly affect secondary metabolite biosynthesis in plants, and irradiance levels have been reported to affect the concentration and production of both phenylpropanoids and carotenoids. Therefore, the objective of the present study was to determine the most effective LED light source in enhancing growth and secondary metabolites (polyphenols and carotenoids) and investigate the effect of LED illumination on production the of primary and secondary metabolites (polyphenols and carotenoids) in Vigna unguiculata L. Walp. sprouts Methods and Results : In order to determine the effect of light-emitting diodes (LEDs) on plant metabolism, the present study examined the primary and secondary metabolite profiles of Vigna unguiculata L. Walp. sprouts that were exposed to red, blue, white, or a combination of red and blue LEDs using high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), gas chromatography-mass spectrometry (GC-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). A total of 39 hydrophilic compounds were identified and quantitated using GC-TOF-MS, and six phenylpropanoids and six carotenoids were quantified using HPLC. The plants grown under blue LED light contained the highest level of total carotenoids (253.72 ± 17.27 ㎍/g) and phenylpropanoids (2,600.51 ± 4.90 ㎍/g). Thus, the current study provides a new approach for enhancing the carotenoid and phenylpropanoid production of V. unguiculata. Conclusion : This study suggests that blue LED light source is the most appropriate for the sprout growth and production of phenolic compounds and carotenoids in cowpea sprouts. Furthermore, these findings confirm that HPLC, GC-MS, and GC-TOF-MS are suitable for investigating metabolic relationships and offer a tenable strategy for enhancing secondary metabolite production using LED light sources.
        32.
        2018.10 서비스 종료(열람 제한)
        Background : Fagopyrum esculentum Moench (common buckwheat) is an important pseudocereal due to high agricultural and medicinal values. It contains various minerals, fiber, and flavonoids. Additionally, flavonoids in buckwheat have various health effects. Thus, this study is aim to optimize the concentration of chitosan, salicylic acid (SA), and jasmonic acid (JA), for the production of phenolics in germinated buckwheat using high-performance liquid chromatography (HPLC). Methods and Results : The treatment with 0.1% chitosan increased the accumulation of all 7 phenolic compounds compared with the control, 0.01 and 0.5% chitosan treatments (p < 0.05). Furthermore, the germinated buckwheat treated with JA at the specific concentrations of 50, 100, and 150 μM increased the accumulation of total phenolic compounds. The germinated buckwheat grown in 150 μM of JA showed the highest amount of total phenolics which was approximately 2.47 times higher than that of control. Particularly, the accumulation of gallic acid, rutin, catechin, chlorogenic acid, and (-)-epicatechin were approximately 2.00, 2.38, 1.76, 2.81, and 7.95 times higher in JA-treated buckwheat than in the control buckwheat samples. A total of seven phenolics, including gallic acid, catechin, chlorogenic acid, caffeic acid, (-)-epicatechin, benzoic acid, and rutin, were detected in germinated buckwheat. Apparently, JA and chitosan treatment enhanced the accumulation of phenolic compounds in the germinated buckwheat. Particularly, the treatments with 0.1 % chitosan and 150 μM JA were the most effective on the accumulation of phenolic compounds. According to the time-course analysis, a 72 h chitosan treatment enhanced the production of phenolics. Similarly, the germinated buckwheat treated with 48 and 72 h showed the accumulation of higher levels of phenolic compounds than the control buckwheat. Conclusion : This study aimed to optimize the concentrations and treatment period of elicitors, chitosan and JA, for the enhanced production of phenolic compounds in germinated buckwheat. Thus, these results might help build sturdy strategies to enhance the production of phenolics in germinated buckwheat as a good nutritional source for human consumption.
        33.
        2018.10 서비스 종료(열람 제한)
        Background : Radish sprouts or young seedlings are important nutritional vegetables in Asian countries. In the present study, we investigated plant growth and levels of glucosinolate accumulation in radish sprouts in response to treatments with different carbon sources. Plant growth and accumulation of glucosinolates were inversely correlated in treatments with different carbon sources. Methods and Results : All the carbon sources used in this study inhibited the growth of shoot and root in radish sprouts and facilitated significantly the accumulation of glucosinolates. Seven different glucosinolate compounds were detected in radish sprouts treated with different carbon sources. The total as well as individual amounts of all the identified glucosinolates increased after treatments with different carbon sources, except for 4-methoxyglucobrassicin and glucoiberin. In particular, the supplementation of sucrose, galactose, and glucose resulted in highest glucosinolate accumulation in radish sprouts. Radish sprouts treated with sucrose showed the highest levels of total glucosinolates, which was 1.22-fold higher than that of untreated sprouts. Furthermore, sucrose treatment resulted in higher production of gluconapoleiferin, glucoerucin, glucoraphasatin, and glucobrassicin compared with that in untreated sprouts, and the treatment of galactose and glucose similarly enhanced glucosinolate production when compared with untreated sprouts. Conclusion : seven glucosinolates were identified by HPLC and great differences in glucosinolates levels were observed in radish sprouts in response to different carbon sources. The glucosinolate production was positively affected by most of the stimuli used in this study. The results presented herein provide information about optimal cultivation conditions, particularly the suitable carbon sources, that will enhance glucosinolate production in radish sprouts.
        34.
        2018.10 서비스 종료(열람 제한)
        Background : Morus alba L. (M. alba L.) belongs to the family Moraceae and has been industrially used as a food source for the silkworm and as a sedative in traditional medicine due to their adaptogenic, hypotensive, anti-inflammatory, hypoglycemic, and anti-adipogenic properties. In this study, metabolic profiling of diploid and tetraploid in Morus alba L. ‘Cheongil’ Methods and Results : Carotenoids are secondary metabolites found in most of the higher plants. In the current study, the levels of carotenoids were much higher in tetraploid of M. alba L. ‘Cheongil’ than diploid of M. alba L. ‘Cheongil’. Particularly, the levels of lutein, 13z-β-carotene, α-carotene, E-β-carotene, and 9Z-β-carotene were 2.51, 5.53, 7.68, 4.43, and 4,46 times higher in tetraploid of M. alba L. ‘Cheongil’, respectively. Additionally, hierarchical cluster analysis (HCA) was carried out using Pearson’s correlation results in order to determine the relationships between metabolites of diploid and tetraploid in Morus alba L. ‘Cheongil’. The results of HCA revealed the degree of correlation among 42 metabolites, which were identified and quantitated by GC-TOFMS. Among TCA organic acids, succinic acid was positively correlated with fumaric acid (r = 0.8250, p < 0.0001) and malic acid (r = 0.9436, p < 0.0001). Among carbohydrates, fructose was positively correlated with glucose (r = 0.9398, p < 0.0001) and mannose (r = 0.9394, p < 0.0001). Conclusion : In this study, we investigated primary metabolites and secondary metabolites (carotenoids) in diploid and tetraploid in Morus alba L. ‘Cheongil’ in order to provide information on the difference between
        35.
        2018.10 서비스 종료(열람 제한)
        Background : Morus alba L. (M. alba L.), belonging to the family Moraceae, is widely distributed in East Asia. Fruits of M. alba L. have been used in traditional herbal medicine due to their antioxidant, anticancer, and antidiabetic properties. Phenolics play a main role for the growth, development, and pigment accumulation of plants. In this study, metabolic profiling of white (M. alba L. ‘Turkey’) and red (M. alba L. ‘Cheongil’) fruits during maturation. Methods and Results : Phenolic compounds are secondary metabolites found in most of the higher plants. In the current study, the levels of phenolic compounds decreased during the maturation of Turkey and Cheongil fruits. Particularly, the Turkey fruits showed a dramatic decrease in the accumulation of phenolics. Principal component analysis (PCA) is one of powerful tools to identify overall patterns in the multivariat experimental data. The PCA score plots results revealed a clear classification between Cheongil and Turkey. Additioanlly, each group spread left to right in the X-axis by maturity. Two principal components of the score plot explained 71.1% of the total variance. Principal component 1 was associated with the separation of each group by maturity and isolation of Turkey 1. Conclusion : In this study, we investigated primary metabolites and secondary metabolites (phenolics) in the white fruits (M. alba L. ‘Turkey’) and red fruits (M. alba L. ‘Cheongil’) in order to provide information on change in metabolite patterns during maturation.
        36.
        2018.10 서비스 종료(열람 제한)
        Background : Agastache rugosa (A. rugosa), belonging to the Lamiaceae family, is a medicinal plant mainly distributed in Korea and contains various phenolic compounds revealing anti-fungal and anti-HIV properties. This study is aim to investigate change in phenylpropanoid content of flowers at different developmental stages using high performance liquid chromatography (HPLC) and quantitative real time polymerase chain reaction (qRT-PCR). Methods and Results : The variation in the transcriptional level of phenylpropanoid biosynthetic genes and phenylpropanoid contents in the flowers of A. rugosa at different developmental stages was analyzed. The transcript levels of phenylpropanoid biosynthesis genes, including ArPAL (phenylalanine ammonia-lyase), ArC4H (cinnamate 4-hydroxylase), and ArCHS (Chalcone synthase), were high in flowers at 1st stage compared with flowers at 2nd and 3rd stages. On the other hand, the expression levels of flavonoid biosynthesis genes, including ArTAT (tyrosine amino transferase), ArHPPR (hydroxyl phenylpyruvate reductase), and ArRAS (rosmarinic acid synthase), were higher in flowers at 3rd stage than those of flowers at 1st and 2nd. These results were consistent with HPLC analysis revealing that most phenolic compounds were higher in flowers at 1st and 2nd stage but the level of rosmarinic acid was the highest in 3rd stage. Conclusion : Our findings provide the information on change in phenylpropanoid biosynthesis in A. rugosa flowers at different developmental stages.
        37.
        2018.10 서비스 종료(열람 제한)
        Background : Galantamine is mainly obtained from the bulbs and flowers of Galanthus caucasicus, Galanthus woronowii, and other related genera such as Narcissus tazetta, Narcissus pseudonarcissus, Leucojum aestivum, and Lycoris radiata. Galantamine is used to treat Alzheimer’s disease (AD) and as an AD painkiller. Narcissus tazetta (N. tazetta), belonging to the Amaryllidaceae family, is a ornamental plant containing galantamine. In this study, metabolic profiling of N. tazetta different organs was performed. Methods and Results : The amount of galantamine in bulb of N. tazetta is the highest levels. About 0.61 ± 0.09 ㎎/g in bulb, 0.15 ± 0.17 ㎎/g in root, and 0.10 ± 0.0 ㎎/g in leaf. Contents of galantamine in root and leaf are not statistically significant. The total phenolic contents in leaf are the highest level. Rutin and kaempferol are identified all part of N. tazetta. On the other hands, 4-hydroxybenzoic acid is existed in leaf and caffeic acid is only existed in root. None of the bulbs except rutin and kaempferol are identified. Because plant secondary metabolism is closely related to plant primary metabolism, we used GC-TOF-MS on the levels of hydrophilic low-molecular-weight molecules in the N. tazetta. A total of 41 metabolites, including sugars, amino acids, organic compounds, and phenolic acids, were identified and measured, and the resulting quantitative data were subjected to principal components analysis (PCA). The results of PCA of metabolic profiles clearly showed the lack of marked variance among different organs of L. radiata. Two principal components of the score plot explained 86.79% of the total variance (component 1; 55.40%, component 2; 31.39%). Component 1 resolved the separation of leaves from the other plant parts. Conclusion : Narcissus tazetta belongs to amaryllidaceae family. These family has various alkaloids, in particular, galantamine is beneficial to Alzheimer patients. All parts of N. tazetta produce galantamine, in particular, the highest level is existed in the bulb. In contrast, phenolic compounds are identified
        38.
        2018.10 서비스 종료(열람 제한)
        Background : Members of Amaryllidaceae family produce several alkaloids with unique structures and a variety of medicinal properties. Galantamine, in particular, is one of the alkaloids approved by the Food and Drug Administration (FDA), and the European Registration Bureau for treatment of Alzheimer’s disease. Lycoris radiata (L. radiata), belonging to the Amaryllidaceae family, is a bulbous plant containing galantamine, which exhibits selective and dominant acetylcholinesterase inhibition. In this study, metabolic profiling of L. radiata different organs was performed. Methods and Results : Galantamine in root, bulb, and leaf of L.radiata analyzed by high performance liquid chromatography (HPLC). The amount of galantamine in leaf is about 1.07 ± 0.17 ㎎/g and it is the higher than bulb (0.88 ± 0.01 ㎎/g) and root (0.75 ± 0.01 ㎎/g). These results are statistically significant. Six phenolics are identified in L. radiata through high performance liquid chromatography. Total amounts of phenolics are the highest in bulb. Because plant secondary metabolism is closely related to plant primary metabolism, we used GC-TOF-MS on the levels of hydrophilic low-molecular-weight molecules in the L. radiata. A total of 41 metabolites, including sugars, amino acids, organic compounds, and phenolic acids, were identified and measured, and the resulting quantitative data were subjected to principal components analysis (PCA). The results of PCA of metabolic profiles clearly showed the lack of marked variance among different organs of L. radiata. Two principal components of the score plot explained 89.4% of the total variance (component 1, 51.86%; component 2, 37.54%). Component 1 resolved the separation of leaves from the other plant parts. Conclusion : Amaryllidaceae family synthesize galantamine belonging to alkaloids. Particularly, in bulb of Lycoris radiata, galantamine contents are the highest level. Thus, bulb is very beneficial for Alzheimer’s disease because the galantamine is well known as treatment of dementia of Alzheimer type.
        39.
        2018.10 서비스 종료(열람 제한)
        Background : Narcissus tazetta (N. tazetta), belonging to the Amaryllidaceae family, is a bulbous plant distributed in Korea, China, and Japan. Amaryllidaceae family plants contained galantamine exhibiting dominant and selective acetylcholinesterase inhibition. In this study, transcriptome analysis of N. tazetta was carried out. Methods and Results : The results of studies conducted in duplicate revealed the presence of a total of 305,228 and 370,567 unigenes, acquired from 69,605,788 and 59,770,506 raw reads, respectively, after trimming the raw reads using CutAdapt, assembly using Trinity package, and clustering using CD-Hit-EST. The resulting unigenes were annotated based on the NCBI Non-redundant protein database, as N. tazetta is genetically closer to Phoenix dactylifera and Elaeis guineensis. The unigenes of N. tazetta were clustered into three major categories: biological processes, cellular components, and molecular functions, with 51 functional sections. A large number of unigenes (11,371 and 15,535 from replicates 1 and 2, respectively) were categorized in the biological process cluster, followed by the cellular component cluster, and the molecular function cluster. With respect to the biological process category, the unigenes were assigned to 23 functional sections. The majority of unigenes were involved in cellular processes. Among the unigenes clustered as the cellular component with 14 sections, most genes were associated with the cell and cell parts. Furthermore, 156,584 and 201,353 unigenes, respectively, matched the molecular function cluster with 14 sections, of which most unigenes were related to metabolic process and cellular process. Conclusion : This study provides functional information of N. tazetta and highlights the use of the Illumina platform for transcriptome research.
        40.
        2018.10 서비스 종료(열람 제한)
        Background : Lycoris radiata belongs to the Amaryllidaceae family and is a bulbous plant native to South Korea, China, and Japan. Galantamine, a representative alkaloid of Amaryllidaceae plants, including L. radiata, exhibits selective and dominant acetylcholinesterase inhibition. In this study, transcriptome analysis of L. radiata was performed. Methods and Results : Genes for galantamine biosynthesis were used to design primers for qRT-PCR. Quantitative RT-PCR was performed with LrActin as a reference gene for normalization. The RT-PCR results reveal the expression of LrPAL A and LrC4H at an early stage in the pathway. Interestingly, the expression of these genes was significantly higher in roots. However, the expression levels of LrNNR and LrN4OMT, which are closely involved in galantamine biosynthesis, were significantly higher in bulbs than leaves and roots. The expression levels of LrPAL B, LrTYDC, LrCYP98A3 and LrCYP76T were not significantly different among the different parts of the plants tested. HPLC analysis confirmed the presence of galantamine in all the organs, including the root (0.53 ± 0.07 ㎎/g dry weight), bulb (0.27 ± 0.04 ㎎/g dry weight), and leaf (0.75 ± 0.09 ㎎/g dry weight). The galantamine level in the bulb was 1.42 and 2.78 times higher than that in the root and leaf, respectively. The results of qRT-PCR for the eight galantamine genes revealed relatively high levels of genes expressed early, including LrPAL A, LrPAL B, LrC4H, and LrTYDC in the roots. However, in the bulbs, the levels of LrNNR and LrN4OMT were higher, which are crucial for galantamine biosynthesis. It also explains why bulbs contain high amounts of galantamine, which is likely due to the increased expression of LrNNR and LrN4OMT and the high levels of LrCYP96T, although the genes expressed early were expressed at high levels in the root. Conclusion : Transcript data of plants grown in a growth chamber revealed high expression levels of LrNNR and LrN4OMT genes that are closely involved in galantamine biosynthesis, and, as expected, we observed higher amounts of galantamine in the bulbs than in the root and leaves.
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