• Korean journal of applied entomology
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• v.37 no.1
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• pp.31-37
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• 1998

Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic similarity among 8 clones of apierous green peach aphid, two types (M. persicae Sulzer and M. nicotianae lack man) classified by their mo~hologi~cahla raters and host preference (Blackman, 1987), collected from tobacco plants. The genetic variation among these clones was evaluated by polymerase chain reaction amplification with 20 random primers. The higher GC contents of primers, the better in amplification efficiency of PCR reaction in general. The genetic similarities among eight aphid clones were analyzed from UPGMA (unweighted pair group average method) cluster analysis based on simple matching coefficient. The range of genetic similarity coefficients was 0.414 to 0.808. The most close relationship among the clones was similarity coefficient of 0.808 between the PG2 and the PG3 clone. The eight aphid clones analyzed were clustered into three groups by the genetic similarity coefficient. The first group, PG1, PG2, PG3 clone including in M. persicae type by their morphological characters and RED clone in M. nicotianae type was clustered at the genetic similarity coefficient of 0.643. The second group, GR1, GR2, BRN in M. nicotianae type was at the 0.636;and the third group was DBR clone in M. persicae type. The results did not indicate any correlation between m&-phological types (M. persicae and M. nicotianae) and RAPD polymorphism. We could not detect any obvious genetic relationships of the two morphological types of the green peach aphid collected from tobacco plants.

• Korean journal of applied entomology
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• v.23 no.4 s.61
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• pp.203-208
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• 1984

Four varieties of tobacco, Nicotiana tabacum var. NC 2326. NC 95, NC 744 and Havana. and two plant species, Physalis floridana Rydb., N. repanda Wild. were used for classification of ten isolates of potato virus Y(PVY) obtained Iron potato or tabacco plants showing various symptoms. Each of the 10 isolates could be distinguished by the host reactions showing necrosis, vein banding and/or mottling, or no symptom on these hosts. Five isolates of PVY, PVY-VN, PVY-N, PVY-NSNR, PVY-Chile, and PVY-Argentina, showed necrotic symptom on NC 2326, but others showed vein handing and/or mottling symptom. On NC95, each of the isolates tested showed similar symptons as on NC2326, except necrotic symptom by the isolate PVY-MSNR. Havana showed mottling reaction to the PVY-NSNR, PVY-MSNR, PVY-MSMR, PVY-VB, and necrosis to PVY-Chile, PVY-Argentina, but showed no symptom to the others. NC744 showed mottling symptom to the PVY-MSNR and PVY-MSMR, necrosis to the PVY-Chile and PVY-Argentina, and no symptom to the others. On N. repanda, necrotic reaction to PVY-Argentina. no symptom to PVY-VN and PVY-C, and nettling to others were observed.

• Journal of Periodontal and Implant Science
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• v.50 no.2
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• pp.106-120
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• 2020

Purpose: A new form of porous polyethylene, characterized by higher porosity and pore interconnectivity, was developed for use as a tissue-integrated implant. This study evaluated the effectiveness of porous polyethylene blocks used as an onlay bone graft in rabbit mandible in terms of tissue reaction, bone ingrowth, fibrovascularization, and graft-bone interfacial integrity. Methods: Twelve New Zealand white rabbits were randomized into 3 treatment groups according to the study period (4, 12, or 24 weeks). Cylindrical specimens measuring 5 mm in diameter and 4.5 mm in thickness were placed directly on the body of the mandible without bone bed decortication, fixed in place with a titanium screw, and covered with a collagen membrane. Histologic and histomorphometric analyses were done using hematoxylin and eosin-stained bone slices. Interfacial shear strength was tested to quantify graft-bone interfacial integrity. Results: The porous polyethylene graft was observed to integrate with the mandibular bone and exhibited tissue-bridge connections. At all postoperative time points, it was noted that the host tissues had grown deep into the pores of the porous polyethylene in the direction from the interface to the center of the graft. Both fibrovascular tissue and bone were found within the pores, but most bone ingrowth was observed at the graft-mandibular bone interface. Bone ingrowth depth and interfacial shear strength were in the range of 2.76-3.89 mm and 1.11-1.43 MPa, respectively. No significant differences among post-implantation time points were found for tissue ingrowth percentage and interfacial shear strength (P>0.05). Conclusions: Within the limits of the study, the present study revealed that the new porous polyethylene did not provoke any adverse systemic reactions. The material promoted fibrovascularization and displayed osteoconductive and osteogenic properties within and outside the contact interface. Stable interfacial integration between the graft and bone also took place.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.2
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• pp.105-115
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• 2002

Objective : To evaluate the effects of the reactive oxygen species (ROS) generated with a xanthine (X) and xanthine oxidase (XO) system on sperm function, the change of sperm characteristics, lipid peroxidation, and DNA fragmentation in bovine spermatozoa. Materials and Methods: ROS were produced using a combination of 1000 uM X and 50 mU/ml XO. The ROS scavengers: superoxide dismu tase (SOD) (200 U/ml) and catalase (500 U/ml) were also tested. Spermatozoa were incubated for 2 hours in BWW medium with a combination of X-XO supplemented with or without ROS scavengers at $37^{circ}C$ under 5% $CO_2$ incubator. Sperm movement characteristics by CASA (computer-aided sperm analysis), HOST (hypoosmotic swelling test), Caionophore induced acrosome reaction, malondialdehyde formation for the analysis of lipid peroxidation, the percentage of DNA fragmentation using the method of TdT-mediated nick end labelling (TUNEL) by flow cytometry were determined after 2 hours incubation. Results: The action of ROS on bovine spermatozoa resulted in a decreased in capacity for sperm motility, Ca-ionophore induced acrosome reaction and membrane integrity, an increased in malondialdehyde formation and the percentage of sperm with DNA fragmentation. In the effects of antioxidant, catalase completely alleviated the toxic effects induced by the ROS in terms of sperm function and characteristics, however SOD exhibited no capacity to reduce the toxic effects. Conclusion: The ROS can induce significant damages to sperm functions and characteristics. The useful ROS scavengers can minimized the defects of sperm function and various damages of spermatozoa.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.43-46
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• 2007

The samples were synthesized by using a solid state reaction. The X-ray diffraction pattern for $Ti_{0.96}Co_{0.02}Fe_{0.02}O_2$ showed a pure rutile phase with tetragonal structures. Mixtures of the proper proportions of the elements sealed in evacuated quartz ampoule were heated at $870{\sim}930^{\circ}C$ for one day and then slowly cooled down to room temperature at a rate of $10^{\circ}C/h$. In order to obtain single phase material, it was necessary to grind the sample after the first firing and to press the powders into pellets before annealing them for a second time in evacuated and sealed quartz ampoule. Magnetic properties have been investigated using the vibrating sample magnetometer(VSM). Room temperature magnetic hysteresis(M-H) curve showed an obvious ferromagnetic behavior and the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $1.3{\mu}_B/CoFe$. But the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $0.02{\mu}_B/CoFe$ without Ti-getter.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.21-29
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• 1998

The rare-earth orthoborate family, RM3(BO3)4 is known to be the most promising material for the microlaser host. To grow LaSc3(BO3)4 single crystal, the phase relation of the system LaBO3-ScBO3 was investigated by DTA method. LaSc(BO3)4 was the unique intermediate compound in the binary system the peritectic reaction point of which was 1495 ±2℃. Owing to the peritectic behavior of the compound, the crystal growth of the rare-earth Sc-borate was carried out by pulling from the melt-soultion of La1+xSc3-x(BO3)4. The optimal conditions for the growth of LaSc3(BO3)4 were determined by traditional CZ method : pulling speed 0.7mm/hr, rotation speed 7-10 rpm under reduction condition. Pt and Ir crucibles could be used for about 8-10 times of growth. The effect of thermal configurations on the temperature distribution was investigated. A special two-coordinate manipulator was made for the precise movement of thermocouples from the melt to the top of the furnace for several thermal configurations. The radial gradient on the melt surface depends strongly on the construction of the afterheater. On the other hand, the axial gradient was mainly propotional to both the opening degree of baffle plate and the mutual positions of crucible and heater.

• Korean Journal of Plant Resources
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• v.16 no.3
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• pp.230-237
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• 2003

This study was conducted to investigate the occurrence and characterization of tobacco mosaic virus(TMV) in Chinese foxglove isolated from the field of the Chonbuk province(Jinan, Jangsu, Jeongeup). TMV was detected in all three regions and confirmed positive reaction by ELISA test. In the host range test, Chenopodium amaranticola, Nicotiana glutinosa, N. tabacum cv. 'Bright yellow', N. tabacum cv. 'KY­57, Datura stramonium were locally infected with the virus. The virus produced mosaic symptom on inoculated leaves of N. tabacum cv. 'Samson'. However, Chenopodium quinoa, Glycine max, Raphanus sativus, Cucumis sativus, Cucurbita moschata, Brassica rape and Lycopersion esculentum did not show any symptoms. TMV particles were revealed as a stiff rod shape by transmission electron microscopic(TEM) and measured as 300 nm in length with 18 nm in diameter. Total RNA was extracted from showing symptom loaves infected with TMV and the reverse transcription­polymerase chain reaction (RT­PCR) obtained 531 bp DNA product of RNA with specific primer used. The capsid protein of TMV­RE showed higher amino acid sequence homology(97.7％) with TMV­To than with TMV­P(72.2％). The capsid protein of TMV­152 showed same amino acid sequence homology with TMV­F. The result of comparison of nucleotides sequence homology between TMV­RE strain and other TMV strain showed 94％ homology with others except TMV­P(67.3％) and TMV ­ C(68.6％).

• Research in Plant Disease
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• v.27 no.3
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• pp.120-127
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• 2021

Plant viruses cause significant yield losses, continuously compromising crop production and thus representing a serious threat to global food security. Tomato spotted wilt virus (TSWV) is the most harmful plant virus that mainly infects horticultural crops and has a wide host range. Reverse-transcription quantitative real-time PCR (RT-qPCR) has been widely used for detecting TSWV with high sensitivity, but its application is limited owing to the lack of standardization. Therefore, in this study, a sensitive and accurate reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) method was established for TSWV detection. Additionally, we compared the sensitivities of RT-qPCR and RT-ddPCR for TSWV detection. Specificity analysis of RT-ddPCR for TSWV showed no amplification for main pepper viruses and negative control. TSWV transcripts levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity; however, the former yielded results that were at least 10-fold more sensitive and detected lower TSWV copy numbers than the latter. Collectively, our findings show that RT-ddPCR provides improved analytical sensitivity and specificity for TSWV detection, making it suitable for identifying low TSWV concentrations in field samples.

• Research in Plant Disease
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• v.29 no.1
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• pp.52-59
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• 2023

Cucurbit chlorotic yellows virus (CCYV) is a plant virus that causes damage to cucurbit crops such as watermelon and cucumber, and is transmitted by an insect vector known as the whitefly. Since CCYV was first detected on cucumber in Chungbuk in 2018, it has been reported in other areas including Gyeongsang in Korea. In 2020, we performed field surveys of yellowing diseases in the greenhouses growing melon and watermelon in Chungbuk (Jincheon and Eumseong). Reverse transcription-polymerase chain reaction analysis of 79 collected samples including melon, watermelon, and weeds resulted in detection of CCYV in 4 samples: Three samples were singly infected with CCYV and one samples was mixed infected with CCYV, Cucurbit aphid borne yellows virus, and Watermelon mosaic virus. The complete genome sequences of the four collected CCYV melon isolates (ES 1-ES 4) were determined and genetically compared with those of previously reported CCYV isolates retrieved from GenBank. Phylogenetic analyses of RNA 1 and 2 sequences revealed that four ES isolates were clustered in one group and closely related to the CCYV isolates from China. The analysis also revealed very low genetic diversity among the CCYV ES isolates. In general, CCYV isolates showed little genetic diversity, regardless of host or geographic origins. CCYV has the potential to pose a serious threat to melon, watermelon, and cucumber production in Korea. Further studies are needed to examine the pathogenicity and transmissibility of CCYV in weeds and other cucurbits including watermelon.

• Parasites, Hosts and Diseases
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• v.27 no.2
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• pp.109-118
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• 1989

Production of circulating specific antibodies to the lung fluke (Paragenimus westermani) by its host is well known and used in various kinds of immunodiagnostic methods, However, it has not been well documented which compartments (or structures) of the lung fluke are most responsible for the production of specific antibodies. The present immunohistochemical study was undertaken to demonstrate the antigenicity of each body compartment of p. westermani such as suckers, tegument, spines, vitelline glands, intestine, reproductive organs(male and female), and eggs. Indiret immunoperoxidase(IP) stain technique was applied, using formalin-fked, paraffin- embedded lung tissues of P westermani-infected cats sectioned in 4 Um thickness as the antigen and cat antisera (11~20 weeks of infection) as the primary antibody. Peroxidase-conjugated goat anti-cat IgG was used as the secondary antibody and diaminobensidine(DAB) as the coloring agent. Strong yellow or yellowish brown staining was regarded positive. The primary and secondary antibody dilutions were made at 1 : 500~1 : 2, 000 and 1 : 200~1 : 500 respectively, and IP stain was repeated 10 times for each dilution. A consistent result obtained was that the intestinal epithelial border, intestinal content, vitelline glands, and eggs scattered around the worm capsule showed strong positive staining, while uterine eggs and some parenchymal portions showed weak positive reaction. On the other hand, the suckers, tegument, spines, subtegumental cells, cytoplasm of intestinal epithelial cells, male reproductive organs, and ovary revealed negative staining. The body compartments showing higher antigenicity were, in the decreasing order, the intestinal epithelial border, intestinal content, eggs in the worm capsule, vitelline glands, uterine eggs, and parenchymatous portions. The intestinal epithelial border and luminal contents revealed positive staining even at a few concentration of 1 : 4, 000 primary antibody(secondary ab., 1 : 200) whereas the parenchymatous portion showed positive reaction only at higher concentrations than 1'500 (secondary ab., 1 : 200). The results suggest that the specific antibody responses of the host to p. westermani occur most strongly upon the excretes from the intestinal epithelium of the worm and e99s Produced around the worm capsule,