• Tuberculosis and Respiratory Diseases
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• v.59 no.3
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• pp.250-256
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• 2005

Background : Fluoroquinolone drugs are an important anti-tuberculous agent for the treatment of multi-drug resistant tuberculosis. However, many drugs belonging to the fluoroquinolones have different cross resistance to each other. Methods : Sixty-three ofloxacin (OFX) resistant and 10 pan-susceptible M. tuberculosis isolates were selected, and compared for their cross resistance using a proportion method on Lowenstein-Jensen media, containing ofloxacin (OFX), ciprofloxacin (CIP), levofloxacin (LVX), moxifloxacin (MXF), gatifloxacin (GAT) and sparfloxacin (SPX), at concentrations ranging from 0.5 to $3{\mu}g/ml$. DNA extracted from the isolates was directly sequenced after amplifying from the gyrA and gyrB genes. Results : The 63 OFX resistant M. tuberculosis isolates showed complete cross resistance to CIP, but only 90.5, 44.4, 36.5 and 46.0% to LVX, MXF, GAT, and to SPX, respectively. Fifty-one of the isolates (81.0%) had point mutations in codons 88, 90, 91 and 94 in gyrA, which are known to be correlated with OFX resistance. The Gly88Ala, Ala90Valand Asp94Ala mutations in gyrA showed a tendency to be susceptible to MXF, GAT and SPX. Only 4 isolates had mutations in the gyrB gene, which did not affect the OFX resistance. Conclusion : About 60% of the OFX resistant M. tuberculosis isolates were susceptible to GAT, SPX and MXF. These fluoroquinolones may be useful in the treatment of TB patients showing OFX resistance.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.51-60
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• 1985

This paper was performed to study the nature of varietal resistance of some Korean-new rice cultivars to the brown planthopper (BPH), Nilaparvata lugens ($ST{\AA}L$). The rice cultivars tested were Cheongcheong, Gaya, Hangangchal, Samgang, Nampoong and Yeongpoong which have been reported as having resistant genes for the BPH. The check varieties were Jinheung, Sangpoong and Chucheong for susceptible and IR-36 for resistant. The factors studied were referred to the seedling responses, preference in feeding and oviposition of BPH, antibiosis (nymphal development, adult emergence and sex ratio, adult body weight, population build-up, feeding amount and amylase activity), and chemical composition (inorganic components, chlorophyll contents, cell wall components, amino acids and esterase isozymes) of leaf- sheath and/or roots of rice plants. In conclusion, the natures of varietal resistance of rice cultivars to the BPH were not only correlated with the resistant reaction of rice plant, but also they were related with the non preference in feeding and oviposition and those resistant cultivars had the antibiotic effects to the insects. Their antibiotic effects of rice cultivars to the BPH would be related with some of the chemical components of rice plants, such as the contents of magnesium oxide (MgO), and chlorophyll and the different esterase isozymes.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.147-153
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• 2017

The purpose of this study was to isolate Escherichia coli from flies and to assess pathogenic genes and antibiotic resistance of the isolates. A total of 188 flies were captured in agricultural environment including fruits farms (n = 19), fermented soybean farms (n = 9), municipal waste (n = 46), livestock farms (n = 66), slaughterhouses (n = 38), and manure ground (n = 10). E. coli isolates of captured flies were tested for pathogenic gene and antibiotic resistance using PCR methods and VITEK2 systems. As a result, E. coli from 63% (119/188) of the captured flies has been detected, and the detection rate of E. coli was the highest (89%, 31/34) in flies captured at particular slaughterhouse. Of the 34 isolates, 94% (32/34) were pathogenic gene (ST gene) positive. Twenty-six percent (31/119) of the E. coli isolates were observed being resistant to one or more antibiotics. Markedly, one of E. coli isolates from Livestock farms was resistant to 7 antibiotics including ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, gentamicin, levofloxacin, and trimethoprim/sulfamethoxazole. In addition, it was ESBL positive. The results of the present study may suggest a risk of transmission of pathogenic and antimicrobial resistant bacteria from flies to livestock environment Therefore, it may need to prevent introducing flies into the agricultural production environment for safe food production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.532-539
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• 2015

Inhibition of osteoclast differentiation is the most important target for prevention of inflammatory bone resorption and bone diseases. Here, we investigated the effect of spinach ethanol extract on osteoclast differentiation in RAW264.7 cells. Spinach was extracted with ethanol at a concentration ranging from 0 to 100% (0, 25, 50, 75, and 100% ethanol). Inhibitory effects of receptor activator of NF-${\kappa}B$ ligan (RANKL)-induced osteoclast differentiation were evaluated using tartrate-resistant acid phosphatase (TRAP) stain assay. The most effective eanol concentration for osteoclast differentiation was 100%. Spinach extract (100% ethanol) suppressed RANKL-induced osteoclast differentiation and TRAP activity. Spinach extract (100% ethanol) also suppressed expression of osteoclast differentiation-related marker genes (NFATc1, c-FOS, cathepsin K, and TRAP) and down-regulated RANKL-induced NF-${\kappa}B$ and ERK phosphorylation during osteoclast differentiation. Taken together, our results suggest that spinach extract is effective against reducing osteoclast differentiation through the NF-${\kappa}B$-mediated pathway.

• Molecules and Cells
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• v.39 no.5
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• pp.426-438
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• 2016

Plant disease resistance occurs as a hypersensitive response (HR) at the site of attempted pathogen invasion. This specific event is initiated in response to recognition of pathogen-associated molecular pattern (PAMP) and subsequent PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). Both PTI and ETI mechanisms are tightly connected with reactive oxygen species (ROS) production and disease resistance that involves distinct biphasic ROS production as one of its pivotal plant immune responses. This unique oxidative burst is strongly dependent on the resistant cultivars because a monophasic ROS burst is a hallmark of the susceptible cultivars. However, the cause of the differential ROS burst remains unknown. In the study here, we revealed the plausible underlying mechanism of the differential ROS burst through functional understanding of the Magnaporthe oryzae (M. oryzae) AVR effector, AVR-Pii. We performed yeast two-hybrid (Y2H) screening using AVR-Pii as bait and isolated rice NADP-malic enzyme2 (Os-NADP-ME2) as the rice target protein. To our surprise, deletion of the rice Os-NADP-ME2 gene in a resistant rice cultivar disrupted innate immunity against the rice blast fungus. Malic enzyme activity and inhibition studies demonstrated that AVR-Pii proteins specifically inhibit in vitro NADP-ME activity. Overall, we demonstrate that rice blast fungus, M. oryzae attenuates the host ROS burst via AVR-Pii-mediated inhibition of Os-NADP-ME2, which is indispensable in ROS metabolism for the innate immunity of rice. This characterization of the regulation of the host oxidative burst will help to elucidate how the products of AVR genes function associated with virulence of the pathogen.

• Journal of Life Science
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• v.30 no.9
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• pp.798-803
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• 2020

Late in the 1960s, South Korea established cultivation technology and began breeding new "Tongil" type rice cultivars by crossing indica and japonica. To date, this cultivation technique has been used to produce a wide variety of cultivars to meet consumer preferences and adapt to extreme weather conditions. Once major genetic traits are no longer segregated through advanced generations, varieties obtained from a cross between different crops may become a new variety. In this study, we confirmed the agronomic traits of F₄, F₅, and F₆ by advanced generation a population in which drought tolerance and brown planthopper (BPH) resistance were crossed. HV23, Ilmi/HV23, and Drimi2ho/HV23 were used. HV23 was drought-tolerant, and Drimi2ho was resistant to BPH. As a result, it was possible to consider that the agronomic traits were fixed because none of them showed a significant difference from the others. While it takes more than 10 years for the pedigree method of breeding, this study confirmed that the agronomic traits were fixed in 4-6 years. In the future, we will investigate the homology of the CaMsrB2 gene and the Bph1 gene, to confirm that both genes are closely related to each other, and analyze the stable inheritance of the introduced gene for multiple successive generations.

• Research in Plant Disease
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• v.10 no.4
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• pp.217-226
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• 2004

One hundred isolates of Magnaporthe grisea from Korea and China were characterized for pathogenicity using eight Korean differential varieties(KDV), six Chinese differential varieties(CDV) and six near isogenic lines(NILs) developed in China. The restriction length polymorphism of M. grisea isolates from each country also was analyzed using MGR586 as a probe. One hundred Korean isolates classified into 17 races on KDV were grouped into 29 pathotypes on Chinese near isogenic lines(NILs). Virulence of 46% of Korean isolates against all the six Chinese NILs indicated that the current six Chinese NILs alone was not enough to be used as differential varieties in Korea. Especially, susceptibility of the BL1 carrying resistance gene Pi-b to 70% of tested Korean isolates suggested that BL1(Pi-b) may not be a useful resistance source to Korean blast. Based on the virulence assays of M. grisea populations from each country were divided into two groups. About 50% of Chinese isolates showed similarity to the 30% of the Korean isolates. Especially, the isolates from northern part of China, where Japonica rice cultivars were grown, showed high similarity to the Korean isolates, while isolates from southern part of China, where Indica rice were mainly grown, showed low similarity to Korean isolates. The genome RFLPs of Korean isolates were quite different from those of southern part of China using MGR586 as a probe. These data indicated that the physiological and genetical characteristics of M. grisea population might be determined by strong interaction with cultivated rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.198-203
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• 2007

This study was carried out to obtain basic informations for gene action of quantitative characters including shattering resistance. The parental varieties used for $5{\times}5$ half diallel crosses were 'Yangbaek' and 'Ansan' of normal type, 'Suwon177' and 'Suwon195' of placenta adhesion type (PA) and 'SIG960320-5-1-1' of indehiscent type (ID). PA and ID type are shattering-resistant sesames, and Yangbaek and Ansan are shattering sesames. All the characters were sufficient to the assumption for diallel analysis in this experiment. Over dominance was exhibited by the number of capsules per plant, while partial dominance by plant height, capsule setting stem length, grain yield per plant and shattering rate, complete dominance by the number of branches per plant. Additive effect was higher than dominance in shattering rate. High shattering rate was dominant over low shattering rate. Suwon 195, shattering resistant sesame, showed to have the many recessive genes which reduced the shattering rate of sesame seed. Broad sense heritability for all the characters was more than 0.8. Narrow sense heritability for the number of branches per plant, the number of capsules per plant, grain yield per plant and shattering rate was 0.45 to 0.63, and plant height and capsule setting stem length was more than 0.8.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.610-616
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• 2011

Clubroot disease caused by Plasmodiophora brassicae, induces damage to cruciferous vegetables worldwide. For control of the disease, many CR (clubroot resistant) $F_1$ hybrid cultivars of Chinese cabbage have been bred and released in Korea. In this study, we determined the race of 10 field isolates of P. brassicae collected from ten regions in Korea using Williams' differential varieties and investigated the degree of resistance of 25 commercial CR cultivars of Chinese cabbage to the isolates. The clubroot pathogens were assigned into two (HS and YC), two (HN1 and HN2), two (DJ and SS) and four (GS, GN, JS, and PC) isolates for race 2, race 4, race 5, race 9, respectively. All CR cultivars showed similar response, resistant or susceptible, to each isolate and the P. brassicae isolates were divided into two groups. Among them, the DJ, GS, GN, HS, and JS isolates could not infect the CR cultivars. In contrast, the SS, HN1, HN2, PC, and YC isolates caused severe clubroot disease on the CR cultivars like susceptible cultivars. Even though they belong to the same race, the CR cultivars showed a different response to the pathogens. The results suggest that the breakdown of CR in Chinese cabbage has already occurred in cultivation areas of Korea and resistance source introduced in CR cultivars may be very limited. In addition, it is likely that resistance genes of Williams' differential varieties to P. brassicae are different from the gene of CR cultivars of Chinese cabbage used in the study.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.290-297
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• 2009

This research aims to contribute the characterization of acetolactate synthase (Ec 4.1.3.18; ALS) and the resistance mechanism by sequence analysis of ALS gene of the sulfonylurea-resistant and -susceptible Monochoria vaginalis. The ALS gene was obtained from susceptible (S) and resistant (R) M. vaginalis to sulfonylurea herbicides (SUs). The 815 bp the fragment and the genomic DNA sequence coding for acetolactate synthase (ALS) of S and R biotypes of M. vaginalis were cloned and sequenced. Nineteen clones were divided greatly into 4 groups as result of sequencing. The first group was not difference to S type, the second group was amino acid of P197S which found point mutations causing substitution of serine for proline at amino acid 197, the third group was observed greatly other part of 6 places than group 1, and the fourth group appeared the intergrade of group 1 and 3. Therefore, it could be assumed what ALS gene of various types can be one plant. The peptide of the 13 amino acid Domain A region for ALS genes from R biotype of M. vaginalis differed from that of the S biotype by one base substitution at proline codon of Domain A. It could also be confirmed that point mutation of serine for proline at amino acid 197.