• BMB Reports
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• 제35권3호
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• pp.255-261
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• 2002

GTP cyclohydrolase I (E.C. 3.5.4.16) is a homodecameric protein that catalyzes the conversion of GTP to 7,8-dihydroneopterin triphosphate (H2NTP), the initial step in the biosynthesis of pteridines. It was proposed that the enzyme complex could be composed of a dimer of two pentamers, or a pentamer of tightly associated dimers; then the active site of the enzyme was located at the interface of three monomers (Nar et al. 1995a, b). Using mutant enzymes that were made by site-directed mutagenesis, we showed that a decamer of GTP cyclohydrolase I should be composed of a pentamer of five dimers, and that the active site is located between dimers, as analyzed by a series of size exclusion chromatography and the reconstitution experiment. We also show that the residues Lys 136, Arg139, and Glu152 are of particular importance for the oligomerization of the enzyme complex from five dimers to a decamer.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.217.1-217.1
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• 2003

In previous study, we investigated the mechanism of suppression of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) by ergolide, sesquiterpene lactone from Inula Britannica. In this study, the suppression of iNOS and COX-2 by ergolide might be attributed to selective inhibition of NF-$\_$K/B signaling pathways. Here, we investigated the suppressionmechanism of NF-$\_$K/B signaling pathways by ergolide in TPA-stimulated HeLa cells. (omitted)

• The Plant Pathology Journal
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• 제18권3호
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• pp.109-114
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• 2002

To evaluate the phylogenetic and taxonomic status of the phytoplasmas associated with water dropwort (Oenanthe javanica DC) disease in Korea and Japan, their 16S rDNA was analyzed. DNAs extracted from water dropworts collected in Korea (Kyongnam province) and Japan (Chiba prefecture) affected by witches' broom and yellows were subjected to PCR using phytoplasma-specific primers, which amplified a 1.4-kbp fragment that included the 16S rDNA. Phytoplasmas were characterized by RFLP analysis using AluI, HaeIII, HhaI, KpnI, MseI, and RsaI restriction enzymes and by sequence analysis of the PCR products. The mater dropwort witches'broom (WDWB) and water dropwort yellows (WDY) 16S rDNA sequences were identical and closely related to onion yellows (OY, 99.9% identity), which belong to the aster yellows (AY) 16S-subgroup. However, the KpnI RFLP analyses clearly distinguished the WDY and WDWB phytoplasmas from the OY phytoplasma. The phylogenetic analysis based on 16S rDNA showed that WDWE and WDY phytoplasmas are members of a relatively homogeneous group that evolved from a common ancestor.

• International Journal of Industrial Entomology and Biomaterials
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• 제46권2호
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• pp.41-54
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• 2023

The blue-tailed damselfly, Ischnura elegans Van der Linden, 1820 (Odonata: Coenagrionidae), is a climate-sensitive indicator species in South Korea. In this study, we sequenced the complete mitochondrial genome (mitogenome) of I. elegans collected from South Korea for subsequent population genetic analysis, particularly to trace population movements in response to climate change. The 15,963 base pair (bp)-long complete mitogenome of I. elegans has typical sets of genes including a major non-coding region (the A+T-rich region), and an arrangement identical to that observed in ancestral insect species. The ATP6, ND3 and ND1 genes have the TTG start codon, which, although rare, is the canonical start codon for animal mitochondrial tRNA. The A/T content was 71.4% in protein-coding genes, 72.1% in tRNAs, 72.9% in the whole genome, 74.7% in srRNA, 75.3% in lrRNA, and 83.8% in the A+T-rich region. The A+T-rich region is unusually long (1,196 bp) and contains two subunits (192 bp and 176-165 bp), each of which is tandemly triplicated and surrounded by non-repeat sequences. Comparison of the sequence divergence among available mitogenomes of I. elegans, including the one from the current study, revealed ND2 as the most variable gene, followed by COII and COI, suggesting that ND2 should be targeted first in subsequent population-level studies. Phylogenetic reconstruction based on all available mitogenome sequences of Coenagrionidae showed a strong sister relationship between I. elegans and I. senegalensis.

• International Journal of Oral Biology
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• 제45권2호
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• pp.58-63
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• 2020

The salivary glands secrete saliva, which plays a role in the maintenance of a healthy oral environment. Under physiological conditions, saliva secretion within the acinar cells of the gland is regulated by stimulation of specific calcium (Ca²⁺) signaling mechanisms such as increases in the intracellular Ca²⁺ concentration ([Ca²⁺]_i) via storeoperated Ca²⁺ entry, which involves components such as Orai1, transient receptor potential (TRP) canonical 1, stromal interaction molecules, and inositol 1,4,5-triphosphate (IP₃) receptors (IP₃Rs). Homer proteins are scaffold proteins that bind to G protein-coupled receptors, IP₃Rs, ryanodine receptors, and TRP channels. However, their exact role in Ca²⁺ signaling in the salivary glands remains unknown. In the present study, we investigated the role of Homer2 in Ca²⁺ signaling and saliva secretion in parotid gland acinar cells under physiological conditions. Deletion of Homer2 (Homer2^-/-) markedly decreased the amplitude of [Ca²⁺]_i oscillations via the stimulation of carbachol, which is physiologically concentrated in parotid acinar cells, whereas the frequency of [Ca²⁺]_i oscillations showed no difference between wild-type and Homer2^-/- mice. Homer2^-/- mice also showed a significant decrease in amylase release by carbachol in the parotid gland in a dose-dependent manner. These results suggest that Homer2 plays a critical role in maintaining [Ca²⁺]_i concentration and secretion of saliva in mouse parotid gland acinar cells.

• Journal of Veterinary Science
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• 제21권3호
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• pp.48.1-48.18
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• 2020

Background: Mature oocytes at the metaphase II status (MII-stage oocytes) played an important role in assisted reproductive technology in non-human primates. Objectives: In order to improve the proportion of MII-stage oocytes retrieval, three different superovulation protocols were performed on 24 female cynomolgus monkeys. Methods: All the monkeys received once-daily injection of follicle-stimulating hormone (25 international unit [IU]) on day 3 of the menstruation, 3-day intervals, twice daily for 8-12 days until the time of human chorionic gonadotropin (1,500 IU) injection, on the 14-17th day of menstruation collecting oocytes. The difference between protocol I and protocol II was that 0.1 mg the gonadotropin-releasing hormone agonist was injected on day 1 of the menstruation, while the difference between personalized superovulation protocol and protocol II was that oocytes could be collected on the 14-17th day of menstrual cycle according to the length of each monkey. Results: The total number of oocytes harvested using the personalized superovulation protocol was much higher than that using protocol I (p < 0.05), and the proportion of MII-stage oocytes was significantly greater than that from either superovulation protocol I or II (p < 0.001 and p < 0.01 respectively), while the proportion of immature oocytes at the germinal vesicle was less than that from superovulation protocol I (p < 0.05). Conclusions: The personalized superovulation protocol could increase the rate of MII-stage oocytes acquired, and successfully develop into embryos after intracytoplasmic sperm injection, and eventually generated fetus.

• Journal of Plant Biology
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• 제39권2호
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• pp.145-148
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• 1996

A new species, Indigofera grandiflora B. Choi et S. Cho, was described from sourthern Korea. The new species is related to I. kirilowii and I. koreana in the Far East. However, the species differs from these two species in having larger flowers and leaflets and hairiness on leaflets. The new species is also allied to I. decora in southest China and Japan, but clearly distinguished from the latter by its larger flowers, shorter inflorescences, and hairiness on leaflets.

• 한국약용작물학회지
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• 제26권4호
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• pp.302-307
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• 2018

Background: A soil-borne pathogenic fungus, Ilyonectria radicicola (Cylindrocarpon destructans) causes root rot on ginseng (Panax ginseng C. A. Meyer) and is known to attack many other plants. The Nectria/Neonectria radicicola complex has been renamed as the I. radicicola complex after analysis of its multi-gene relatedness and morphological characteristics. The fungi in this complex have been reclassified into 16 species under the genus Ilyonectria based on characteristics analysis Methods and Results: To obtain useful data from the Korean ginseng root rot, I. radicicola was isolated from the rhizosphere soils of the chestnut tree. They were identified through a pathogenicity test and a survey of the morphological features. The existence of I. radicicola in soil samples was confirmed by PCR detections using nested PCR with species-specific primer sets. These were subsequenctly isolated on semi-selective media from PCR-positive soils. Genetic analysis of the I. radicicola complex containing these pathogens was done by comparing the DNA sequences of the histone h3 region. These isolates originating from the rhizosphere soils of chestnut constituted a clade with other closely related species or I. radicicola isolates originating from ginseng or other host plants, respectively. Additionally, the pathogenicity tests to analyze the characteristics of these I. radicicola isolates revealed that they caused weakly virulent root rot on ginseng. Conclusions: This is the first study reporting that I. radicicola isolates from chestnut rhizosphere soils can attack ginseng plant in Korea. Thus, these results are expected to provide informations in the selection of suitable fields for ginseng cultivation.

• 한국콘텐츠학회논문지
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• 제10권5호
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• pp.427-435
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• 2010

교과서에 쓰인 과학 용어 네트워크를 구축하여, 네트워크의 구조, 관련 정보 및 연관 관계를 분석하기 위하여 핵심용어를 도출하였다. 본 연구에서는 과학, 생물1 및 생물2 교과서 각 과목별로 출판사 세 곳을 선정하고 각각의 교과서에서 추출한 용어들을 노드로, 한 문장 안에 있는 과학 용어를 링크로 연결하여 네트워크를 구축하였다. 모든 교과서의 과학 용어 네트워크는 척도 없는(scale-free) 네트워크의 특성을 보여주었다. 복잡한 (complex) 네트워크에서 가중치가 낮은 것부터 제거하는 방법인 k-core 알고리즘을 적용하여 핵심 (core) 네트워크를 구축하였는데, 몇 개의 모듈이 연결되는 형태를 보여주었다. 과학교과서의 경우에는 물리, 화학, 생물, 지구과학 분야별로 크게 네 개의 모듈을 형성하였고, 생물1과 생물2 교과서는 각단원별로 용어들이 모여 있는 특성을 지닌 네트워크를 나타냈다. 본 연구에서 복잡한 네트워크에서 핵심네트워크를 구축하여 유용한 정보를 도출할 수 있는 가능성을 제시하였다.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2004년도 제47회 춘계 학술연구 발표회
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• pp.41-42
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• 2004