• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.597-604
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• 2011

Using 108 strains of Vibrio parahaemolyticus isolated from seawater, we investigated ampicillin-resistance profiles and the genetic characterization of ${\beta}$-lactamase (VPA0477). All of the strains studied, except one strain, were resistant to ampicillin. However, the strain that was susceptible to ampicillin had the same ${\beta}$-lactamase gene as the ampicillin-resistant strains. We compared ${\beta}$-lactamase promoter region sequences among five strains, including both ampicillin-resistant and -susceptible strains. In the susceptible strain, a nucleotide at position -19 in the methionine initiation codon for ${\beta}$-lactamase was not present in the ampicillin-resistant strains. The genes in the region containing the gene VPA0477 were present in all of the tested strains, and LA-PCR analysis showed that the distance between VPA0474 and VPA0479 in all of the V. parahaemolyticus samples was precisely 5.7 kb. In V. parahaemolyticus ${\beta}$-lactamase, four important structural features that are conserved in Class A ${\beta}$-lactamases were present in the deduced amino acid sequences. Taken together, our study demonstrates that V. parahaemolyticus ${\beta}$-lactamase is included in the Class A ${\beta}$-lactamase group, and some nucleotides within the promoter region are of particular importance for ${\beta}$-lactamase activity.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.165-170
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• 1987

This experiment was carried out to evaluate the difference in the biochemical characteristic of the brown planthoppers of the insecticide risistant, susceptible strains and their hybrid progenies. Activity of the esterase isozyme separated by electrophoresis method was remarkably high in the resistant strain as compared with the susceptible strain. Esterase activity between the insecticide-treated strains and the non-insecticide strains was not degraded in the resistant strain and the $F_1$, but remarkably degraded in the susceptible strain. The increase of esterase activity was associated with the development of resistance, and that was inherited with a dominant gene.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.128-132
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• 1982

Starch contents in healthy and powdery mildew-infected spring barley leaves at first and fifth leaf stages were measured at different intervals after inoculation. Different patterns of starch accumulation in the susceptible cultivar Peruvian and the adult plant resistant cultivar Asse were found in infected first and fifth leaves. At the early phase of infection, the amount of starch in infected first leaves was slightly changed in both cultivars. During colony development and sporulation, the decrease in starch content was .more marked in the susceptible Peruvian, whereas the amounts of starch in the adult plant resistant Asse increased during colony development and then decreased sharply before and after sporulation. In heavily infected first leaves, the susceptible cultivar Peruvian showed a drastic decrease in starch content. In the adult plant resistant cultivar Asse, the higher amount of starch retained in these infected leaves, regardless of infection intensity. The regulation of starch accumulation in mildewed barley plants at different leaf stages was discussed in relation to adult plant resistance of spring barley.

• Plant Resources
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• v.7 no.3
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• pp.187-194
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• 2004

Sequence-tagged site (STS) markers tightly linked to the bacterial leaf blight (BLB) resistance genes, xa5, xa13 and Xa21, were used in this study. A survey was conducted to find polymorphisms between the resistant and susceptible germplasm in rice. 500 of Korean varieties and 100 of landraces were evaluated in this study. STS marker, RG207 was used to having xa5 resistance gene of rice germplasm. 27 varieties of Korean germplasm showed resistant for xa5 gene. The RG136 an xa-13 marker resulted in a single band of approximately 1kb in all the rice accessions studied. In order to detect polymorphism, digestion of the polymerase chain reaction (PCR) product was performed using a restriction enzyme Hinf Ⅰ. The resistant lines resulted in two bands 0.5kb on digestion with Hinf Ⅰ, while the same enzyme did not digest the PCR product of susceptible lines. No polymorphism was detected in Korean varieties and landraces, indicating that they probably do not contain xa13 gene. pTA248 an Xa-21 marker detected a band of 1kb in the resistant lines and bands of either 750bp or 700bp in the susceptible lines. Among germplasm tested, there are no varieties and landraces with Xa21 resistant gene. The results of the germplasm survey will be useful for the selection of parents in breeding programs aimed at transferring these bacterial blight resistance genes from one varietal background to another.

• Journal of Life Science
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• v.10 no.1
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• pp.107-113
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• 2000

This study carried out to investigate activities of the superoxide dismutase(SOD), peroxidase(POD) and diterpene cyclase of rice plant treated by environmental stress conditions. The rice leaves of Ilpum was shown to have the most highest specific activity of POD. POD activity in the susceptible cv. Ilpum and Hwasung during the disease progress show a increase, while for a decreasing activity in the resistant cv. Dasan. SOD activity of rice plants treated by chitosan were increased as the treatment concentration increased. At the chitosan application, the SOD activity in the susceptible cv. Hwansung at the rice leaves 14days after treatment was higher in treatment than chitosan-untreated control. The activity of POD in the susceptible cv. Ilpum decreased as long as UV-B irradiation, while that in the resistant cv. Dasan increased. Futhermore, activity of that in Dasan were similar to as time on UV irradiation, Hwasung showed two times higher than untreated control at 40 minutes after UV-B exposure. The activity of diterpene cyclase in rice plants inoculated with Pyricularia oryzae has much higher tendency than UV-B irradiation. The activity of diterpene cyclase in the rice leaves gradually increased until 5 days after inoculation with Pyricularia oryzae.

• The Korean Journal of Mycology
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• v.22 no.3
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• pp.260-265
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• 1994

Since around 1980 apple rot caused by Botryosphaeria dothidea has become prevalent throughout the growing areas in Korea, during which period chemical controls have been executed with no notable improvement. Results of investigations on resistance of the causal fungus to its control chemical are as followings; The susceptible fungal isolates showed no mycelial growth at $150\;{\mu}g/ml$ of benomyl whereas the resistant isolates showed 7-13 mm growth at $300\;{\mu}g/ml$ and 6-8 mm at $2,400\;{\mu}g/ml$ of this fungicide. At the latter high concentration, spore germination of the resistant isolates was 5-9% while that of the susceptible isolates was 0%. Within the range of $20-2,400\;{\mu}g/ml$ tested, the susceptible isolates were unable to form pycnidia, but the resistant isolates formed abundant pycnidia at the lower concentration with decreasing pycnidia along with the higher concentration.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.730-736
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• 2015

Tomato spotted wilt virus (TSWV) causes one of the most destructive viral diseases that threatens global tomato production. Sw-5b was reported as the resistance gene effective against TSWV. The objective of this research was to develop a single-nucleotide polymorphism (SNP) marker to distinguish tomato cultivars resistant to TSWV from susceptible cultivars for marker-assisted breeding. First, we determined genotypes for TSWV resistance in 32 commercial tomato cultivars using the previously reported Sw-5b gene-based marker. Then, DNA sequences of Sw-5b alleles in tomato cultivars showing resistant or susceptible genotypes were analyzed; a single SNP was found to distinguish tomato cultivars resistant to TSWV from susceptible cultivars. Based on the confirmed SNP, a SNP primer pair was designed. Using this new SNP sequence and high-resolution melting analysis, the same 32 tomato cultivars were screened. The results were perfectly correlated with those from screening with the Sw-5b gene-based marker. These results indicate that the SNP maker developed in this study will be useful for better tracking of resistance to TSWV in tomato breeding.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.2
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• pp.59-64
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• 2011

Protein kinase C (PKC) is involved in many cellular signaling pathways, it participates in many physiological processes, such as cell cycle, growth, proliferation, differentiation and apoptosis. To investigate the effect of PKC on the silkworm midgut tissue infection of Bombyx mori parvo-like virus (BmPLV), a B. mori atypical protein kinase C (BmaPKC) gene was cloned from larval midgut tissue, expressed in E. coli and purified. Additionally, the BmPLV susceptible silkworm strain and resistant silkworm strain were used to test the effect of the B. mori infection on BmPLV. The result showed that BmaPKC encodes a predicted 586 amino acid protein, which contains a C-terminal kinase domain and an N-terminal regulatory domain. The maximum expression amount of the soluble (His)6-tagged fusion protein was detected after 0.8 mmol/L IPTG was added and cultured at $21^{\circ}C$. The (His) 6-tagged fusion protein revealed about 73 kDa molecular weight which confirmed by western blot and mass spectrography. Furthermore BmaPKC protein were detected at 0-72 h post-infection in BmPLVinfected larval midgut tissue, western blot showed that as time went on, the expression of BmaPKC increased gradually in susceptible strain, the expression quantity on 72 h is 5 times of 0 h. However, in resistant strain, the expression quantity is slightly lower than susceptible strain. But no significant change in resistant strain was observed as time went on. The available data suggest that BmaPKC may involve in the regulation of BmPLV proliferation.

• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.27-40
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• 2021

The construction method to prevent the frost heave or thaw settlement is called the ground stabilization method, and the thermo-syphon is one of the typical ground stabilization methods. The thermo-syphon has recently been developed with a simple analysis model and thermal analysis has been carried out, but the frost heave of frost susceptible soil was not considered. This study was conducted using ABAQUS internal user subroutine to develop the numerical analysis model (Coupled thermo-mechanical) that can simultaneously perform thermal analysis for the temperature change of the soil according to the thermo-syphon and structural analysis to predict the frost heave of the soil accordingly. As a result of the numerical analysis, the frost heave of the soil decreased as the performance of the thermo-syphon increased. As for the main results, when the thermo-syphon which has contain 25%, 50%, and 100% of refrigerant filling ratio was applied, the reduction ratio of the frost heave was 5.5%, 14.4%, and 21% respectively.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.391-398
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• 2011

Physiological responses to salinity stress were evaluated in six rice genotypes differing in their tolerance to salinity at the seedling stage. Susceptible genotypes ('Dongjingbyeo', 'Hwayeongbyeo', and 'IR29') showed salt injury symptoms (mean 8.8) and higher visual score under salt stress than that of tolerant ones ('Pokkali', 'IR74009', and 'IR73571'). As salinity affects growth and physiological parameters, the six genotypes thus showed significant reduction because of salt stress. Tolerant Japonica/Indica bred lines ('IR74009', 'IR73571') showed lower reduction, 33.9%, 34.5%, and 50%, respectively, in plant seedling height, dry shoot weight and dry root weight than those of the susceptible Japonica varieties ('Dongjingbyeo', 'Hwayeongbyeo'), and the highest reduction under salt stress was observed in dry root weight, followed by dry shoot weight and seedling height, respectively. Shoot $Na^+$ concentration of IR74099 and IR73571 was lower than that of the susceptible varieties, 'Dongjinbyeo' and 'Hwayeongbyeo'. There were no significant differences among genotypes in root $Na^+$ concentration. Shoot $K^+$ concentration showed a reverse tendency compared to shoot $Na^+$ concentration. IR74009 and IR73571 had considerably lower ratio compared to 'Dongjinbyeo' and 'Hwayeongbyeo' in $Na^+/K^+$ ratio of their shoot and was not different the tolerant check, 'Pokkali'.