• Research in Plant Disease
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• v.28 no.4
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• pp.221-230
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• 2022

The fire blight caused by Erwinia amylovora (Ea) was first reported in 2015 in Korea, and the disease has rapidly spread to 22 regions until 2021. In Korea, all host plants in the apple and pear orchards where fire blight occurred should be eliminated and buried by the Plant Protection Act. To prevent the spread of the disease, all burial sites were prohibited from planting the new host plants for the next three years. To confirm the eradication efficiency of Ea and the reoccurrence of fire blight, the surveillance facilities were established on three burial sites from 2019 to 2020 in Anseong-si, Gyeonggi-do, and Chungju-si, Chungcheongbuk-do. As host plants, five apple trees of fire blight-susceptible cultivar 'Fuji', were planted in each facility. All facilities were enclosed with fences and nets and equipped with two CCTVs, motion sensors, and several other sensors for recording weather conditions to monitor the environment of the sentinel plants in real-time. The sentinel plants were checked for the reoccurrence of fire blight routinely. Suspicious plant parts were collected and analyzed for Ea detection by loop-mediated isothermal amplification polymerase chain reaction and conventional polymerase chain reaction. Until November 2022, Ea has not been detected in all sentinel plants. These results might support that the burial control of infected plants in soil works efficiently to remove Ea and support the possibility to shorten the prohibition period of host plant establishment in the burial sites.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.442-446
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• 2010

Adenosine 3',5'-cyclic monophosphate (cAMP) is a second messenger responsible for a multitude of cellular responses. In this study, we utilized $\beta$-cyclodextrin ($\beta$-CD) as an artificial receptor with a hydrophobic cavity to elucidate the inclusion kinetics of cAMP in a hydrophobic environment using the ultrasonic relaxation method. The results revealed that the interaction of cAMP with $\beta$-CD followed a single relaxation curve as a result of host-guest interactions. The inclusion of cAMP into the $\beta$-CD cavity was found to be a diffusion-controlled reaction. The dissociation of cAMP from the $\beta$-CD cavity was slower than that of adenosine 5'-monophosphate (AMP). The syn and anti glycosyl conformations of adenine nucleotides are considered to play an important role in formation of the inclusion complex. Taken together, our findings indicate that hydrophobic interactions are involved in the inclusion complex formation of cAMP with $\beta$-CD and provide insight into the interactions of cAMP with cAMP-binding proteins.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.138.2-139
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• 2003

Grapevine leafroll-associated 1 virus (GLRaV-1) and Grapevine leafroll-associated 3 virus (GLRaV-3), member of the genus Ampelovirus, are important viral disease of grapevine in the world. these viruses transmitted only dicotyledonous host by vectors such as mealybugs and there is no suitable herbaceous host for virus. The diseased leaves turn yellowish or reddish depending on cultivars and viruses. Viruses are existed at low concentration and ununiformly distribution in grapevine. Using small-scale double-stranded RNA (dsRNA) extraction method, reverse transcription and polymerase chain reaction (RT-PCR) product of 1Kb long which encoded of coat protein (CP) gene for both viruses was successfully amplified with a specific primers. The RT-PCR product was cloned into the plasmid vector and its nucleotide sequences were determined from selected recombinant cDNA clones. Sequence analysis revealed that the CP of GLRaV-1 consisted of 969 nucleotide, which encoded 323 amino acid residues and CP of GLRaV-3 consisted of 942 nucleotide, which encoded 314 amino acid residues. The CP of GLRaV-1 and GLRaV-3 has 93.8％ and 98.7％ amino acid sequence identities, respectively.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1851-1858
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• 2011

Details of the double-bond isomerization of 1-hexene over H-ZSM-5 were clarified using density functional theory. It is found that the reaction proceeds by a mechanism which involves the Br${\o}$nsted acid part of the zeolite solely. According to this mechanism, 1-hexene is first physically adsorbed on the acidic site, and then, the acidic proton transfers to one carbon atom of the double bond, while the other carbon atom of the double bond bonds with the Br${\o}$nsted host oxygen, yielding a stable alkoxy intermediate. Thereafter, the Br${\o}$nsted host oxygen abstracts a hydrogen atom from the $C_6H_{13}$ fragment and the C-O bond is broken, restoring the acidic site and yielding trans-2-hexene. The calculated activation barrier is 12.65 kcal/mol, which is in good agreement with the experimental value. These results well explain the energetic aspects during the course of double-bond isomerization and extend the understanding of the nature of the zeolite active sites.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1565-1568
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• 2007

A borate compound was adopted as new host material for $Eu^{3+}$, $Tb^{3+}$ and $Tm^{3+}$ activators. The phosphor samples, $Gd_{1-x}Eu_xCa_3(GaO)_3(BO_3)_4$, $Gd_{1-x}Tb_xCa_3(GaO)_3(BO3)_4$ and $Gd_{1-x}Tm_xCa_3(GaO)_3(BO_3)_4$ have been synthesized by conventional solid-state reaction. The crystalline phase for the resulting powders was identified using an X-ray diffraction $system^1$. Their photoluminescence properties under the excitation of UV ray were investigated. The Eu, Tb or Tm-doped $GdCa_3(GaO)_3(BO_3)_4$ emits efficient red, green or blue light, respectively. It was observed that the optimum concentration of Eu or Tb activator for the borate host was much higher than other $Eu^{3+}$ or $Tb^{3+}-doped$ phosphors.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.95-99
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• 1997

To obtain a basic information of breeding for resistance to clubroot in Chinese cabbage, disease incidence, pathogenicity, and varietal response to the pathogen were studied. Incidence of clubroot was observed at 3 districts in Gyeonggi-Do, 2 districts in Kangwon-Do, and 1 district each in Gyeongnam, Geongbuk and Jeonbuk, respectively. Disease infection rate and diseased ara were most severe in northern part of Gyeonggi-Do. The isolates of clubroot collected from 8 different districts were not different in their virulence one another in view of their infection rate and disease severity in Chinese cabbage. The clubroot fungus had a wide host range for the cruciferous vegetables. Disease severity was high in rape, turnip and mustard, moderate in Chinese cabbage and broccoli, and low in kale and cauliflower. All of Korean hybrids of Chinese cabbage tested were highly susceptible to clubroot, but Japanese varieties were resistant to the highly pathogenic isolate (EJ-93) which was isolated from the Chinese cabbage in Korea. The hybrid(F1) between clubroot resistant line(930WG) and the susceptible line(332MS) showed completely resistant reaction, which indicated that clubroot resistance was governed by a dominant gene.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.625-629
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• 1998

Turnip mosaic potyviruses (TuMV) were isolated from Rorippa indica and Armoracia lapathifolia showing mosaic symptoms in field. Identification of the TuMVs were carried out by host reactions of indicator plants, electron micrograph, serological properties and reverse transcription-poly-merase chain reaction (RT-PCR). Both viruses systemically infected Chenopodium quinoa, Nicotiana clevelandii, Brassica rapa, B. campestris subsp. pekinensis, B. juncea and Raphanus sativus, and developed local infection on inoculated leaves of C. quinoa, C. amaranticola, C. album, N. tabacum cv. Xanthi nc and Gomphrena grobosa. However, the viruses did not infect on N. glutinosa, Cucumis sativus and Vigna unguiculata. The filamentous particles, about 720 nm in length, and inclusion bodies were observed from the infected leaf tissues by dipping on electron microscopy. Crude sap of leaf infected with the viruses was reacted positively with an antiserum of TuMV in agar gel double diffusion. For detection of the viruses, RT-PCR was carried out with TuMV--specfic oligonucleotide primer. The RT-PCR products, a 1,092 bp DNA fragment, were obtained from naturally infected leaves of R. indica and A. lapathifolia. In inoculation test to seven cruciferous weeds with TuMV, infection occurred in Arabis glabra, Barbarea orthoceras, Capsella bursa-pastoris, Draba nomorosa var. hebecarpa, Rorippa cantoniensis and Thlaspi arvense.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.519-525
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• 1998

Intraspecific genetic diversity of Korean isolates of Phytophthora drechsleri was investigated based on PCR-RFLP of rDNA along with closely related species in the genus; P. cryptogea, P. melonis, P. erythroseptica, P. cinnamomi, P. cambivora and P. cactorum. Gene regions of nuclear small subunit and internal transcribed spacer (ITS) in rDNA were amplified with polymerase chain reaction and digested with 9 restriction enzymes. Phytophthora species was readily differentiated from each other based on the digestion patterns, however, P. cryptogea was not separable from some isolates of P. drechsleri. Twenty one isolates of P. drechsleri originated from 15 host plants were divided into three distinct groups designated as PdG1, PdG2 and PdG3, respectively. Four isolates in PdG1 were originated from green vegetables and tomato and nine isolates in PdG2 were mainly isolated from medicinal plants. The two groups showed 95.3% homology and four isolates of P. cyptogea came under the groups. However, Eight isolates in PdG3 collected from cucurbits were clearly differentiated from those of PdG1 and PdG2 by 66.5% homology, but completely matched with a Taiwan isolate of P. melonis. Results indicated that three distinct groups exist in Korean isolates of P. drechleri and each group has host preference. In addition, reclassification of the cucurbits isolates are reserved because of their distinct genetic characters from other intraspecific groups in P. drechsleri.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.67-75
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• 2020

Tomato spotted wilt virus (TSWV) is one of the plant viruses transmitted by thrips and causes severe economic damage to various crops. From 2008 to 2011, to identify natural host species of TSWV in South Korea, weeds and crops were collected from 5 regions (Seosan, Yesan, Yeonggwang, Naju, and Suncheon) where TSWV occurred and were identified as 1,104 samples that belong to 144 species from 40 families. According to reverse transcription-polymerase chain reaction, TSWV was detected from 73 samples from 23 crop species, 5 of which belonged to family Solanaceae. Additionally, 42 weed species were confirmed as natural hosts of TSWV with three different life cycles, indicating that these weed species could play an important role as virus reservoirs during no cultivation periods of crops. This study provides up-to-date comprehensive information for TSWV natural hosts in South Korea.

• Applied Microscopy
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• v.43 no.4
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• pp.146-154
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• 2013

Capillaria hepatica (syn. Calodium hepatica) is a parasite found mainly in rodent liver. But, it has also been found in a wide variety of mammals, including humans. This worm is unique as it is the only nematode parasite that is embedded in the liver parenchyma of the host even during the adult stage of the life cycle. They produce eggs that elicit a marked granulomatous reaction that eventually destroys the worms. Fibrosis and lymphoplasmacytic inflammatory infiltration are often observed around adult nematodes embedded in the liver parenchyma of the host. For this reason, complete isolation of this slender worm and observation of the intact ultrastructure is very difficult. In this study, 10 intact whole worms (C. hepatica) were isolated from the liver of 3-week-old mouse after inoculation of artificially embryonated eggs collected from house rats (Rattus norvegicus). Their external structure of was observed with light and scanning electron microscopy. The length of the isolated female and male C. hepatica was approximately 69.60 mm and 36.92 mm, respectively. More detailed ultrastructure, including bacillary band, eggs and vulva in female and spicule and spicule sheath in male C. hepatica was also described.