• Journal of Microbiology
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• v.41 no.1
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• pp.16-21
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• 2003

We have collected eight high-level streptomycin-resistant strains of Pseudomonas marginalis and P. syringae pv. actinidiae which were isolated from kiwifruit orchards in Korea and Japan, The molecular mechanisms of resistance were investigated by the PCR, susceptibility tests, and nucleotide sequence analysis. Of the eight high-level streptomycin-resistant strains, four harbored strA-strB genes, which encode streptomycin-inactivating enzymes. While the three Korean strains of R marginalis did not have plasmid and carried the resistant genes in the chromosomes, the Japanese strain of P. syringae pv. actinidiae had a plasmid containing strA-strB genes. The myomycin susceptibility test demonstrated that the high-level resistance to streptomycin of the remaining four strains is associated with mutations in the rpsL gene. Nucleotide sequence analyses revealed that they contain a single base-pair mutation in codon 43 of their rpsL gene.

• Toxicological Research
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• v.12 no.1
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• pp.21-27
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• 1996

Vitamin C has been well known to be a potential chemopreventive agent for several toxic compounds. It reduced the mutation frequencies of 6-sulfooxymethylbenzo[a]pyrene (SMBP) and 6hydroxymethylbenzo[a]pyrene (HMBP) in Salmonella typhimurium TA98 and TA100, indicating that corbic acid affects both frameshift and base-pair substitution mtltations. A similar type of dose-response relationship was shown in the V79 cells, although the inhibitory effect was less dramatic compared with that in S. typhimurium. However, SMBP or HMBP binding to calf thymus DNA was not affected by the presence of vitamin C, suggesting that SMBP seems to be much more reactive to calf thymus DNA than vitamin C. This was supported by migration pattern and fluorescence intensity of SMBP-modified plasmid on the gel. These restilts were not correlated with mutation tests in bacterial and mammalian cell systems. It has been already reported that vitamin C inactivates SMBP through the formation of covalently bound addact. It was found from HPLC analysis that the reaction between vitamin C and SMBP was accomplished within just 5 min and then produced the several products. These findings indicate that the beneficiary of vitamin C is not merely derived from the covalent adducts. On the other hand, the addition of DNA to incubation mixture reduced the amounts of vitamin C adducts while the magnitude of HMBP peak increased, suggesting that DNA accelerates the SMBP hydrolysis to intercept the interaction between SMBP and vitamin C or forms rapidly complex with SMBP.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.183-190
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• 1998

A cDNA expression library of Clonorchis sinensis adult worm was constructed, and screened out immunologically. One clone, pBCs31, was selected ill view of its predominant reactivity with an experimentally infected rabbit serum. Recombinant C. slnensis antigen iIi 28 kDa as a if-falactosidase fusion protein produced in EscherichiG coli was identified by immunoblot analysis. The cloned gene was composed of 16 copies or a 30 base pair repeat and an additional 320 bases. The deduced amino acid seqiLence of the tandem repeat was AQPPKSGDGG. On RNA slot blot analysis, C. sinensis adult worm RNA showed a positive reaction with the cloned gene Enzyme-linked immunosorbent assay using a purified recombinant antigen of pBCs31 showed higtl specificity for diagnosis of clonorchiasis.

• Molecules and Cells
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• v.43 no.2
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• pp.121-125
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• 2020

The identification of adult stem cells is challenging because of the heterogeneity and plasticity of stem cells in different organs. Within the same tissue, stem cells may be highly proliferative, or maintained in a quiescent state and only to be activated after tissue damage. Although various stem cell markers have been successfully identified, there is no universal stem cell marker, which is exclusively expressed in all stem cells. Here, we discuss the roles of master developmental regulator RUNX1 in stem cells and the development of a 270 base pair fragment of the Runx1 enhancer (eR1) for use as stem cell marker. Using eR1 to identify stem cells offers a distinct advantage over gene promoters, which might not be expressed exclusively in stem cells. Moreover, RUNX1 has been strongly implicated in various cancer types, such as leukemia, breast, esophageal, prostate, oral, skin, and ovarian cancers-it has been suggested that RUNX1 dysfunction promotes stem cell dysfunction and proliferation. As tissue stem cells are potential candidates for cancer cells-of-origin and cancer stem cells, we will also discuss the use of eR1 to target oncogenic gene manipulations in stem cells and to track subsequent neoplastic changes.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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• pp.261-270
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• 2010

This paper presents an analytical investigation for a baseline-free imaging of a defect in plate-like structures using the time-reversal of Lamb waves. We first consider the flexural wave (A0 mode) propagation in a plate containing a defect, and reception and time reversal process of the output signal at the receiver. The received output signal is then composed of two parts: a directly propagated wave and a scattered wave from the defect. The time reversal of these waves recovers the original input signal, and produces two additional side bands that contain the time-of-flight information on the defect location. One of the side band signals is then extracted as a pure defect signal. A defect localization image is then constructed from a beamforming technique based on the time-frequency analysis of the side band signal for each transducer pair in a network of sensors. The simulation results show that the proposed scheme enables the accurate, baseline-free detection of a defect, so that experimental studies are needed to verify the proposed method and to be applied to real structure.

• Fisheries and Aquatic Sciences
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• v.25 no.9
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• pp.489-497
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• 2022

The first specimen (54.8 mm standard length) of Ernogrammus zhirmunskii Markevich & Kharin, 2011, belonging to the family Stichaeidae, was recorded in Dokdo, East Sea, Korea on July 26, 2021. This species was characterized by a single ventral lateral-line canal from the posterior margin of the pelvic-fin base extending to the anus and one or two rigid spines on the posterior part of the anal fin. This species is similar to Ernogrammus hexagrammus and Ernogrammus walkeri but differs in the number of ventral lateral-line canal present, with E. zhirmunskii consisting of one (unpaired) ventral lateral-line canal compared to other two Ernogrammus species, which have a pair of parallel ventral lateral-line canal. For further analysis of species identification, a partial gene sequence from the mitochondrial DNA cytochrome oxidase subunit I (554 bp) of E. zhirmunskii was obtained for the first time. This study documents the first record of E. zhirmunskii in Korean waters and proposes the new Korean name of 'Il-gob-julbe-do-la-chi' for the species.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.774-779
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• 2015

In this paper, we present the design and implementation of a large-scale qualitative spatial reasoner using Apache Spark, an in-memory high speed cluster computing environment, which is effective for sequencing and iterating component reasoning jobs. The proposed reasoner can not only check the integrity of a large-scale spatial knowledge base representing topological and directional relationships between spatial objects, but also expand the given knowledge base by deriving new facts in highly efficient ways. In general, qualitative reasoning on topological and directional relationships between spatial objects includes a number of composition operations on every possible pair of disjunctive relations. The proposed reasoner enhances computational efficiency by determining the minimal set of disjunctive relations for spatial reasoning and then reducing the size of the composition table to include only that set. Additionally, in order to improve performance, the proposed reasoner is designed to minimize disk I/Os during distributed reasoning jobs, which are performed on a Hadoop cluster system. In experiments with both artificial and real spatial knowledge bases, the proposed Spark-based spatial reasoner showed higher performance than the existing MapReduce-based one.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.281-286
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• 2014

This study was conducted to investigate the individual size and age of Kaloula borealis, a pair in amplexus. In June 2013, the total 23 pairs of Kaloula borealis were captured in the wetland located in Seongsan-eup and Daejeong-eup, Jeju Island. Size and age of each individual have been examined and as a result of analyzing SVL (snout-vent length), weight, length of forelimb and hindlimb of the collected 23 pairs, the females were shown to have the heavier weight and the longer SVL and hindlimb compared to males. No significant difference in the length of forelimb has been found between the female and the male. The average age of the male of the pair in amplexus was shown to be $5.17{\pm}0.26$, whereas the female was shown to be $6.22{\pm}0.28$, which indicates the higher average age in female compared to the male. The age range of Kaloula borealis was distributed from at least 3 years to 10 years at the maximum. A positive correlation was shown between age of the male and SVL; however, no significant difference was found in female. This study result expected to be utilized as an important base data in establishing the preservation and restoration strategy of endangered species, Kaloula borealis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.4
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• pp.277-284
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• 1998

Random amplified polymorphic DNA (RAPD) analysis was used to detect the genetic diversity of soybean (Glycine max (L.) Merr.) varieties and field bean (Glycine soza Sieb. and Zucc.) Five soybean varieties and one field bean were analysed with random primers using the polymerase chain reaction (PCR). Nine primers of a total twenty random primer were selected to amplify DNA segments. A total of 74 PCR products were amplified and 67.6% of which were polymorphic. The size of DNA molecule is ranged 0.13~2.0Kb and typically generated four to eight major bands. Specific genetic marker were revealed in primer sequence 5'-CAG GCC CIT C-3', 5'-TGC TCT GCC C-3' and 5'-GTC CAC ACG G-3', respectively. Genetic similarity between each of the varieties were calculated from the pair-wise comparisons of amplification products and a dendrogram was constructed by an unweighted pair-group method with arithmethical means (UPGMA). The results indicate that intervarietal relationships of soybean have a narrow genetic base and between the varieties, Hwanggum-kong and Seckryang-bootkong is more closely related than the rest of varieties, and field bean is related quite distant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.342-350
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• 1989

Maturity and spawning of Crangon affinis were studied based on the histological observation. The samples were monthly collected in Nakdong estuary from June, 1988 to May, 1989. The gonad lies on the dorsal side of the thorax. The cavity in which it lies is located below heart and above hepatopancreas. Anterior part of ovary is fused roundly, and the posterior part shows a pair of tubule-like structure. Testis is bilaterally symmetrical; the anterior part shows convoluted tubule, and the posterior part consists of a pair of tubule. Seminal vesicle is connected and opened to the base of the fifth pereiopod. Gametogenesis of ovum and spermatozoon is being repeated in short period without seasonality, and it is formed simultaneously in the whole parts of germinal epithelium. Diameter of a ripe oocyte is ca. $430{\mu}m$. Spermatozoa is oval with distinct nucleoplasm. Reproductive cycle is performed in ca. 40 days. Crangon affinis spawns all year round except November. Incubation period of brooded eggs took $12\~14$ days before hatching in the aquarium at $21^{\circ}C\~24^{\circ}C\;and\;33\%_{\circ}$.