• Research in Plant Disease
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• v.12 no.3
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• pp.298-302
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• 2006

An isolate of Cucumber mosaic virus(CMV), called as Can-CMV, was originally isolated from Canna generalis showing typical streak mosaic foliar symptoms, and its properties were investigated in this study. Whereas all known isolates of CMV could induce symptoms on their systemic hosts(four kinds of Nicotiana spp and a zucchini squash), Can-CMV induced no symptoms on its systemic hosts tested. Replication and movement of the virus on upper leaves as well as inoculated leaves-were confirmed by RT-PCR suggesting that Can-CMV could only infect systemically on N. benthamiana and N. glutinosa. Size of local lesions on the Can-CMV-inoculated leaves of Chenopodium amaranticolor was much smaller than that of Fny-CMV. Whereas Fny-CMV and LS-CMV could induce distinct necrotic local lesions on Vigna unguiculata 2 to 3 days postinoculation(dpi), chlorotic spots symptom was expressed by Can-CMV 4 to 5 dpi. Virus-specific 4 kinds of dsRNAs were isolated from leaves of N. benthamiana infected with Can-CMV, and these dsRNAs corresponded to the viral genomic RNAs and subgenomic RNAs and their patterns were indistinguishable to those of Fny-CMV and LS-CMV. By restriction mapping analysis of 950 bp of RT-PCR amplified products of coat protein gene of the virus as well as by serological analysis of gel diffusion test, Can-CMV belongs to a typical member of CMV subgroup IA. These results suggest that the Can-CMV isolated from C. generalis possesses unique pathological properties to understand further insight into the various interactions between virus and host.

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.304-310
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• 1999

Background: IFN-$\gamma$ plays an important role in host response to intracellular organisms such as mycobacterium. Human infection with mycobacterium leads to a wide variety of outcomes, ranging from asymptomatic infection to widespread and rapidly fatal disease. Recent reports suggest that alteration of the function of IFN-$\gamma$ caused by a defective IFN-$\gamma$ receptor gene can explain different host response to mycobacterium. In this study, we investigated the role of IFN-$\gamma$ in the development of chronic refractory tuberculosis. Methods: The LPS-induced TNF-$\alpha$ production with or without IFN-$\gamma$ priming was compared by using monocytes taken from recently diagnosed tuberculosis, chronic refractory tuberculosis patients and controls. And the IFN-$\gamma$ receptor was measured by indirect fluorescent antibody technique to know whether change in the priming effect of IFN-$\gamma$ is related to IFN-$\gamma$ receptor deficiency or not. Results: The ratio of TNF-$\alpha$ produced in response to stimulation with INF-$\gamma$ and LPS to LPS alone was $13.5{\pm}7.6$ in controls, $10.8{\pm}6.4$ in recently diagnosed tuberculosis patients and $6.7{\pm}3.9$ in chronic refractory tuberculosis patients. The priming effect of IFN-$\gamma$ significantly decreased in chronic refractory tuberculosis patients compared with that in controls(p=0.002). However, IFN-$\gamma$ receptor deficiency was detected in one of chronic refractory tuberculosis patients. Conclusion: The decrease of the priming effect of IFN-$\gamma$ may play an important role in the development of chronic refractory tuberculosis, and in some patients, this may be related to the IFN-$\gamma$ receptor deficiency.

• Research in Plant Disease
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• v.18 no.4
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• pp.310-316
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• 2012

Gibberellea fujikuroi species (Gf) complex comprises at least 15 species, most of which not only causes serious plant diseases, but also produces mycotoxins including fumonisins. Here, we focused on the abilities of the field isolates belonging to the Gf complex associated with rice and corn, respectively in Korea to produce fumonisin, all of which were confirmed to carry FUM1, the polyketide synthase gene essential for fumonisin biosynthesis. A total of 88 Gf complex isolates (55 F. fujikuroi, 10 F. verticillioides, 20 F. proliferatum, 2 F. subglutinans, and 1 F. concentricum), and 4 isolates of F. commune, which is a non-member of Gf complex, were grown on rice substrate and determined for their production levels of fumonisins by a HPLC method. Most isolates of F. verticillioides and F. proliferatum, regardless of host origins, produced fumonisin $B_1$ and $B_2$ at diverse ranges of levels ($0.5-2,686.4{\mu}g/g$, and $0.7-1,497.6{\mu}g/g$, respectively). In contrast, all the isolates of F. fujikuroi and other Fusarium species examined produced no fumonisins or only trace amounts ($<10{\mu}g/g$) of fumonisins. Interestingly, the frequencies of relatively high fumonisin-producers among the F. proliferatum and F. fujikuroi isolates derived from corn were higher than those among the fungal isolates from rice. In addition, it is a first report demonstrating the ability of the FUM1-carrying F. commune isolates from rice to produce fumonisins.

• Molecules and Cells
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• v.39 no.11
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• pp.790-796
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• 2016

Dental pulp is a highly vascularized tissue requiring adequate blood supply for successful regeneration. In this study, we investigated the functional role of stem cells from human exfoliated deciduous teeth (SHEDs) as a perivascular source for in vivo formation of vessel-like structures. Primarily isolated SHEDs showed mesenchymal stem cell (MSC)-like characteristics including the expression of surface antigens and in vitro osteogenic and adipogenic differentiation potentials. Moreover, SHEDs were positive for NG2, ${\alpha}$-smooth muscle actin (SMA), platelet-derived growth factor receptor beta ($PDGFR{\beta}$), and CD146 as pericyte markers. To prove feasibility of SHEDs as perivascular source, SHEDs were transplanted into immunodeficient mouse using Matrigel with or without human umbilical vein endothelial cells (HUVECs). Transplantation of SHEDs alone or HUVECs alone resulted in no formation of vessel-like structures with enough red blood cells. However, when SHEDs and HUVECs were transplanted together, extensive vessel-like structures were formed. The presence of murine erythrocytes within lumens suggested the formation of anastomoses between newly formed vessel-like structures in Matrigel plug and the host circulatory system. To understand underlying mechanisms of in vivo angiogenesis, the expression of angiogenic cytokine and chemokine, their receptors, and MMPs was compared between SHEDs and HUVECs. SHEDs showed higher expression of1VEGF, SDF-$1{\alpha}$, and $PDGFR{\beta}$ than HUVECs. On the contrary, HUVECs showed higher expression of VEGF receptors, CXCR4, and PDGF-BB than SHEDs. This differential expression pattern suggested reciprocal interactions between SHEDs and HUVECs and their involvement during in vivo angiogenesis. In conclusion, SHEDs could be a feasible source of perivascular cells for in vivo angiogenesis.

• Molecules and Cells
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• v.40 no.4
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• pp.299-306
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• 2017

The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.585-597
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• 2003

Porphyromonas gingivalis has been implicated as an important periodontophathic bacterium in the etiology and progression of periodontal diseases. It has been reported that P.gingivalis may mediate periodontal destruction not only directly through its virulence factors, but also indirectly by including complex host mediated inflammatory reponses. The purpose of this study was t o evaluate the effects of P.gingivalis on the bone formation and resorption by osteoblasts. For this purpose, after determining the concentration below which sonicated P.gingivalis extracts (SPEs) have no cytotoxicity on mouse calvarial primary osteoblastic (POB) cells, we investigated the effects of SPEs on the alkaline phosphatase (ALP) activity, matrix metalloproteinase (MMP) expression (MMP-2, -9, 13), and prostaglandin $E_2$ ($PGE_2$) release in POB cells by treatment with SPEs below that concentration. The results were as follows; 1. SPEs showed no cytotoxic effect on POB cells up to a concentration of 1 ${\mu}m$/ml. 2. The treatment with SPEs reduced ALP activity in a dose-dependent manner in POB cells, In addition, when we investigated the effect of SPEs (1 ${\mu}m$/ml) on ALP activity for different exposure periods, statistically significant inhibition of ALP activity was shown at 2 days of exposure, and further significant inhibition occurred by extending the periods of exposure. 3. The treatment with SPEs stimulated the gene expression of MMP-9 in POB cells. 4. The pre-treatment with SPEs increased the amount of $PGE_2$ released in POB cells. In summary, the present study shows that P.gingivalis could inhibit osteogenesis and stimulate bone resorption not only by reducing ALP activity but also by increasing MMP-9 mRNA expression in osteoblasts, possibly through an endogenous $PGE_2$ pathway. In addition, our results suggest that if P.gingivalis affects osteoblasts in early differentiation stage, such effects by P. gingivalis could be irreversible.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.9-14
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• 2003

The pBT-L transgenic mice carrying human TPO gene in conjunction with bovine $\beta$-casein promoter express human TPO in milk during lactation. In this study, stability of germ line transmission and expression of pBT-L transgene integrated into host chromosome were monitored up to generation F10 of transgenic pBT-L/15 line. When male mouse of generation F8 was crossbred with normal females, approximately half of offsprings (51.3$\pm$18.98%) were identified as transgenic mice. Generation F9 and F 10 mice also showed similar transmission rates (43.8$\pm$18.98% and 71.4$\pm$26.98%, respectively), implying that pBT-L transgene can be transmitted stably up to long term generation in the transgenic mice. Expression levels of human TPO from milk of generation F9 and F10 mice were 1.1$\pm$0.33 mg/ml and 1.1 $\pm$0.45 mg/ml, respectively, which are similar to expression level of generation F2 mice. In conclusion, our results suggest that transgenic animals once established will continuously pass their transgenes to the progeny through the breeding program with the same productivity of human protein in their milk.

• Research in Plant Disease
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• v.10 no.4
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• pp.331-336
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• 2004

The fungus genus Sclerotinia contains a number of important plant pathogens. Vegetable growers in our country are probably most familiar with Sclerotinia sclerotiorum, the causes of sclerotinia rot on crisphead lettuce. S. sclerotiorum has a wide host range which can include lettuce as well as crops such as broccoli, cabbage, carrots, celery, beans, peppers, potatoes, stocks, and tomato. Some fungicides, including benomyl, are effective in some crops, but not all. So, we isolated a antagonistic bacteria that are active on sclerotinia rot caused by S. sclerotiorum and that can be used to control it. About 702 strains had been isolated from soil around plant roots in the field. Ten strains showed strong antifungal activity against S. sclerotiorum. In pot test for antagonistic activity, A-7 strain showed high control value against the pathogen when compared with others. The strain was, therefore, selected as a biocontrol candidate against sclerotinia rot and its biochemical properties and 16S rDNA sequence was analyzed. The A-7 strain was highly related to Bacillus subtilis and B. amyloliquefaciens. To confirm precise identification, we had performed gyr A gene sequences analysis. Its sequence had 96% similarity with B. amyloliquefaciens. Consequently, the isolate was identified as B. amyloliquefaciens A-7.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.437-441
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• 2019

Verticillium wilt disease is caused by a fungal plant pathogen Verticillium dahliae, which attacks commercial crops such as chrysanthemum. The conventional methods so far used to identify this fungal pathogen require high expertise and are time-consuming. Therefore, in this study, we developed an assay for the rapid and specific detection of V. dahliae infection using loop-mediated isothermal amplification (LAMP) method. For this assay, four primers for LAMP were designed for targeting cellulose-growth-specific protein partial mRNA gene in Verticillium dahliae. Under standard condition, the optimum reaction temperature for amplification is around 60 ℃ within 60 minutes. This LAMP assay was designed to amplify only present in V. dahliae. When this LAMP assay applied to the DNAs for four other soil-borne fungi and host plants, no amplification was detected. Therefore, this LAMP assay we developed for V. dahliae is expected to do detection at the early stage of its infection. The fast and reliable detection method will allow us to develop effective management system to monitor and control infection of this pathogen in chrysanthemum plant.

• Research in Plant Disease
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• v.19 no.4
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• pp.243-253
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• 2013

Rice blast is one of the most serious disease threatening stable production of rice. Breeding of resistant cultivars has been used as the most effective and useful method to controll rice blast caused by Magnaporthe oryzae. To collect rice blast isolates in fields and test their pathogenicity on new cultivars are important for establishment of new resistant cultivars breeding program of rice. Pathotypes of Korean rice blast isolates have been categorized to Korean differential race system developed in 1985. However, it is little known about genetic background of Korean differential cultivars, so that it is hard to understand for relationship between each pathogen and each host plant at genetic level. In this study, we suggested necessity of a new differential system by analyzing pathogenic responses between 24 monogenic rice lines and 200 Korean rice blast isolates. In addition, we determined the nine representative resistant genes based on the resistance responses of the monogenic lines to rice blast isolates, indexed resistant responses of the monogenic lines to ten representative rice blast isolates and selected 30 Korean representative rice blast isolates proper to Korean system. We think the newly developed differential race system can be broadly used to select resistant cultivars to rice blast in Korea.