• Journal of Life Science
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• v.22 no.10
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• pp.1384-1391
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• 2012

Five coastal plant species, Artemisia fukudo, Aster sphathulifolius, Plantago camtschatica, Sedum oryzifolium, and Setaria viridis, were collected from the coastal region of Ulleung Island (Ulleung-Do, South Korea). Thirty-six endophytic fungi were isolated from the roots of these plants, and all were identified by using PCR with the following specifications: internal transcribed spacer 1 (ITS1), 5.8S rRNA, and ITS2 regions. Phylogenetic analysis indicated that all fungal strains belong to the phylum Ascomycota and comprise four orders (Capnodiales, Eurotiales, Hypocreales, and Pleosporales). Among all the identified species, the Eurotiales species were more abundant than species in the other orders. Nine different genera (Alternaria, Aspergillus, Cladosporium, Exserohilum, Fusarium, Neosartorya, Penicillium, Phoma, and Pyrenochaeta) in the four orders were confirmed. Penicillium and Aspergillus species were the most dominant species among the endophytic fungi isolated from the coastal plants. Shannon's diversity index (H') ranged from 0.684 to 1.609, and the endophytic fungi in S. oryzifolium was more diverse compared to the endophytic fungi in the other plants.

• KSBB Journal
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• v.10 no.5
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• pp.491-498
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• 1995

In order to fraclionate ${\alpha}$-, ${\beta}$- and ${\gamma}$-cyclodextrins(CDs) from CD reaction mixture, various CD adsorbents were manufactured using fatty acids as the ligand molecules and anion exchange resins as matrix. Among several anion exchange resins, DEAE Cellulose was found to be the most suitable matrix for binding fatty acid. The binding stability between DEAE Cellulose and capric acid was tested under the various operation conditions, such as temperature, ethanol concentration, and ionic strength. Specific CD adsorbents manufactured with different chain-length fatty acids, saturated and unsaturated, were compared in terms of the recovery yield and selectivity of ${\alpha}$-, ${\beta}$- and ${\gamma}$-CDs. Stearic acid (C18, saturated) was identified as the most effective ligand for fractionation of ${\alpha}$-CD, and linoleic acid ((C18, unsaturated ) for ${\beta}$-CD. The spacer length between the matrix and ligand was required for effective adsorption of CDs, and the double bond in fatty acid molecules was also acted as an important factor determining recovery yield and selectivity. The elusion patterns of ${\alpha}$- and ${\alpha}$-, ${\beta}$-CD from column packed with stearic acid and linoleic acid CD adsorbents were also investigated at the various elusion conditions for fractionation of ${\alpha}$- and ${\beta}$-CD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.113-119
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• 2006

Brazing is an important manufacturing process in the fabrication of Heavy Water Reactor fuel rods, in which bearing and spacer pads are joined to Zircaloy-4 cladding tubes. The physical vapor deposition(PVD) technique is currently used to deposit metallic Be on the surfaces of pads as a filler metal. Amorphous Zr-Be binary alloys which are manufactured by rapid solidification process are under developing to substitute the conventional PVD-Be coating. In the present study, brazed joint with PVD and amorphous alloys of $Zr_{1-x}Be_{x}(0.3{\le}x{\le}0.5)$ as filler metals are compared by mechanism, microstructure and hardness. The thickness of brazed joint with amorphous alloys became much smaller than that of PVD-Be. The erosion of base metal did not occur in the brazed joint with amorphous alloys. The brazing mechanism for PVD-Be seems to be Be diffusion into Zr-4 with capillary action resulting from eutectic reaction while that for amorphous alloys are associated with the liquid phase formation in the brazed joint. The brazed joint microstructure with PVD-Be consists of dendrite while that with amorphous alloys is globular. The $Zr_{0.7}Be_{0.3}$ alloy shows the smooth interface with little erosion in the base metal and is recommended a most suitable brazing filler metal for Zircaloy-4.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.262-268
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• 2014

A fungal isolate DUCC5000 from a garden plant Pachysandra terminalis was identified as Paraconiothyrium brasiliense based on the results of morphological and molecular studies. The fungus formed brown to black conidiomata of (0.2-0.7)-2(-3.5) mm singly or as a group on PDA. Conidia measured $2-5{\times}1.8-3{\mu}m$ in size, hyaline, ellipsoid to short-cylindrical, and rounded at both ends. The internal transcribed spacer (ITS) DNA of the isolate shared 100% nucleotide sequence homology with those of known P. brasiliense isolates. Phylogenetic tree inferred from the ITS sequence analysis showed that the DUCC5000 isolate formed a clade with known isolates of P. brasiliense. The fungal mycelia grew better on oatmeal agar than on MEA and PDA. On PDA media under various pH conditions, fungal mycelial growth was observed at pH 9. Colony morphology of the fungus tended to alter depending on the kinds of nutrient media and pH condition. On chromagenic media, the fungus demonstrated its ability to produce extracellular enzymes including amyalse, avicelase, ${\beta}$-glucosidase, protease, and xylanase. However, in pathogenicity testing, no disease symptoms were observed on the leaves of P. terminalis. This strain is the first report on P. terminalis in Korea.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.193-199
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• 2018

The fungus, Podosphaera pannosa, was identified in 1991 as the cause of powdery mildew symptoms on peach (Prunus persica var. persica) fruit from Korea based on the morphological characteristics of the conidial state. Recently, however, in Serbia and France, the cause of 'rusty spot' found on peach fruit was identified as P. leucotricha, and the cause of 'powdery mildew' on nectarine (Prunus persica var. nucipersica) fruit was identified as P. pannosa. To confirm the identity of the Korean pathogen, we collected four samples of powdery mildew from Korean peach fruit: three with the 'powdery mildew' symptom and one with the 'rusty spot' symptom. Morphological examination of the four samples confirmed P. pannosa as the pathogen. Internal transcribed spacer sequences of rDNA were analyzed for molecular characterization. A phylogenetic tree showed that the Korean isolates were clustered into a clade containing P. pannosa from Rosa species, with high sequence similarities of more than 99%. Thus, we showed that the powdery mildew and rusty spot symptoms on peach fruits from Korea are associated with P. pannosa.

• Mycobiology
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• v.45 no.4
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• pp.297-311
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• 2017

Saprolegniasis is one of the most devastating oomycete diseases in freshwater fish which is caused by species in the genus Saprolegnia including Saprolegnia parasitica. In this study, we isolated the strain of S. parasitica from diseased rainbow trout in Korea. Morphological and molecular based identification confirmed that isolated oomycete belongs to the member of S. parasitica, supported by its typical features including cotton-like mycelium, zoospores and phylogenetic analysis with internal transcribed spacer region. Pathogenicity of isolated S. parasitica was developed in embryo, juvenile, and adult zebrafish as a disease model. Host-pathogen interaction in adult zebrafish was investigated at transcriptional level. Upon infection with S. parasitica, pathogen/antigen recognition and signaling (TLR2, TLR4b, TLR5b, NOD1, and major histocompatibility complex class I), pro/anti-inflammatory cytokines (interleukin $[IL]-1{\beta}$, tumor necrosis factor ${\alpha}$, IL-6, IL-8, interferon ${\gamma}$, IL-12, and IL-10), matrix metalloproteinase (MMP9 and MMP13), cell surface molecules ($CD8^+$ and $CD4^+$) and antioxidant enzymes (superoxide dismutase, catalase) related genes were differentially modulated at 3- and 12-hr post infection. As an anti-Saprolegnia agent, plant based lawsone was applied to investigate on the susceptibility of S. parasitica showing the minimum inhibitory concentration and percentage inhibition of radial growth as $200{\mu}g/mL$ and 31.8%, respectively. Moreover, natural lawsone changed the membrane permeability of S. parasitica mycelium and caused irreversible damage and disintegration to the cellular membranes of S. parasitica. Transcriptional responses of the genes of S. parasitica mycelium exposed to lawsone were altered, indicating that lawsone could be a potential anti-S. parasitica agent for controlling S. parasitica infection.

• Polymer(Korea)
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• v.28 no.4
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• pp.314-320
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• 2004

Soluble aromatic polyimides bearing 4-(4-oxyalkyleneoxystyryl)- pyridines (ethylene and hexylene) as photoreactive side groups were synthesized and characterized. The photoreactive polymers were soluble in various polar organic solvents and their films were easily formed by solution casting. The photoreactivities of the polymers in the film state were approximately 64% at an exposure energy of 1.5 J/$\textrm{cm}^2$. Transmittances of the polymer films were about 85% after annealing at 20$0^{\circ}C$. Therefore, these polymers can be evaluated to be photoreactive polyimides with good transparency and solubility. The dichroic ratios of the polymers with ethylene and hexylene groups as the alkylene spacers were 0.023 and 0.026, respectively. The order parameters of 4'-pentyl-4-bipheny1carbonitrile as a liquid crystal (LC) in the film cells of the former and latter polymers were 0.50 and 0.52, respectively. These results indicate that the polymers show the effect of alkylene spacer on the photoalignments. The LC in the film cells of the polymers was perpendicularly oriented to the electric vector of the linear polarized UV light (LPUVL).

• Research in Plant Disease
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• v.18 no.2
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• pp.133-138
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• 2012

In November 2009, a powdery mildew on glossy abelia (Abelia ${\times}$ grandiflora) was found in Seogwipo, Jeju Island, Korea. Further survey in the southern part of Korea, e.g., Jeju, Busan, and Tongyeong confirmed occurrence of the disease. White colonies were present on leaves, young stems, and flowers, detracting from their beauty in landscape plantings. Severely infected lesions were discolored to red-purplish. Based on the morphological characteristics and analysis of rDNA, the fungus associated with the symptoms was identified as Erysiphe abeliicola U. Braun & S. Takam. This work provides the morphological feature of its anamorph for the first time, which is characterized by having multi-lobed hyphal appressoria and short foot-cells of conidiophores. Morphological characteristics of mature chasmothecia were consistent with the previous Japanese record of this species. The sequence of internal transcribed spacer region of ribosomal DNA obtained from a Korean sample showed that this species places in the section Microsphaera of the genus Erysiphe in phylogenetic position, corresponding with the classical taxonomy. This is the first report of E. abeliicola and its host plant in Korea. The host plant A. ${\times}$ grandiflora is newly listed in the host range of E. abeliicola.

• Journal of Veterinary Clinics
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• v.31 no.6
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• pp.527-530
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• 2014

A 7-year-old neutered male Korean domestic short-haired cat was referred to our clinic to treat constipation which had persisted for 6 months. The rectal examination revealed narrowing of the right lateral portion of the pelvic canal. A reduced pelvic canal diameter by pelvic fracture malunion was revealed on radiography. The pelvic canal diameter ratio measured from preoperative was 0.68. Based on rectal and radiographic examinations, constipation caused by pelvic canal narrowing was confirmed. Pelvic symphyseal distraction-osteotomy and iliac wedge osteotomy were performed. An iliac osteotomy of the ilium was performed to ease the pelvic symphyseal distraction. After the symphysis was split longitudinally, pelvic symphyseal distraction was maintained by using a spacer made of poly-methyl-methacrylate. The osteotomy of the ilium was fixed using a bone plate and screws. Increased pelvic canal diameter was confirmed on post-operative radiography and the postoperative pelvic canal diameter ratio was 0.91. The patient received antibiotics, NSAIDs, crystalloids and Lactulose for post-operative care. The cat recovered normal defecation abilities and did not have constipation at one week postoperatively. No episodes of constipation persisting longer than 6 months have been reported by owners in previous studies. Pelvic symphyseal distraction osteotomy and iliac wedge osteotomy may prove to be a useful surgical procedure to treat pelvic canal stenosis that is caused by pelvic fracture malunion.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.12-26
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• 2002

The phylogenetic relationships for 33 strains belonging to the genera Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium were conducted by the sequence analyses of the ITS regions. The sequence homologies of these strains showed the high variations(28.0 - 94.9%). According to the phylogenetic analysis of ITS regions. 37 ITS clones from 33 strains of 32 species were classified into four groups. Group I included all strains of the genus Sinorhizobium as core members and R. giardinii as a peripheral member. The genus Rhizobium strains were clustered into group II which was very heterogeneous and the tree toplogy of this group were very unstable. Among the members of group II. the taxonomic position of R. radiobacter and R. rubi was not clearly identified on the basis of ITS I regions. R. undicola and R. vitis were remotely related with other Rhizobium strains including R. leguminosarum, R. galegae, R. gallicum, R. mongolense, R. tropici, R. hainanense, R. rhizogense and R. huautlense of group II were supposed to be loosely related to R. leguminosarum. While the stains of the genera Bradyrhizobium constituted group III with Azorhizobium caulindans, the strains of the genus Mesorhizobium formed group IV on the relatively high sequence homology level.