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        검색결과 33

        22.
        2009.05 구독 인증기관·개인회원 무료
        This study was performed to investigate the bacterial diversity isolated from the twospotted spider mite and to interpret their correlation between insect bacteria and acaricide resistance. Twospotted spider mite, Tetranychus urticae was used the resistance strains, which developed over eight years to the six acaricides such as abamectin, acequinocyl, bifenozate, etoxazole, fenpropathrin, and pyridaben, respectively. After cultivating the bacteria from body maceration, bacterial colony was selected and identified through 16S rRNA gene sequences. We are identified six genus from Pyridaben resistant strain, five genus from acequinocyl, three genus from abamectin, bifenozate, etoxazole, and two genus from fenpropathrin. However, we could not found correlation between bacterial density and diversity (phylotypes) among these resistant strains. By analyzing the diversity of population microorganisms, fenpropathrin was showed 40% of Cs value (Similarity coefficient) with susceptible strain, however, abamectin and pyridaben were perfectly different (0%) with susceptible strain. It remains to be learned about how microorganisms co-evolutionary developed with their host insect correlating to the resistance and how microorganisms play role in acaricide resistant mite.
        23.
        2009.05 구독 인증기관·개인회원 무료
        Upon oviposition, parasitoid wasps inject their eggs along with venom, teratocytes and polydnavirus (PDV) on the host. Among these parasitic factors, PDVs are known to suppress the host immune system and utilize the host translational mechanisms allowing the juvenile parasitoid to develop. Polydnavirusencoded genes can selectively inhibit host translation and still use the translation machinery of the host to synthesize their own proteins. In this study, we utilize a proteomic approach involving two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) that couples isoelectric focusing (IEF) and SDS-PAGE to resolve complex protein mixtures that results from the parastization of Cotesia plutellae on the lepidopteran host, Plutella xylostella. We specifically analyze the changes in protein synthesis using this technique after treatment of HTIFs that has been previously identified on C. plutellae. The difference in protein profile due to parasitization was confirmed by in vitro translation assay using rabbit reticulosyte lysate.
        24.
        2008.10 구독 인증기관·개인회원 무료
        Tobacco whitefly-Bemisia tabaci is considered one of the most important pests in tropical and subtropical agriculture, as well as in production systems in glasshouses in temperate zones. Principle research on the identity of B. tabaci began with the recognition of more than one biotype differing in life history parameters, host plant associations, plant-related damage and insecticide resistance. Our laboratory strains of B. tabaci were identified and classified as biotype B and Q, through mtCOI PCR. Also, they were tested for their host plant preference and reaction to different insecticide. Biotype Q prefers to feed on red pepper and tomato, was less susceptible to tested insecticides, for instance acetamipirid, spinosad and thiamethoxam, than the biotype B (feed on tomato alone). There has been a report on the presence of gut bacteria in B. argentifolii (= B. tabaci biotype B) and its influence on the host insect processes. Hence, as a further pursuit, we examined our laboratory B. tabaci biotypes B and Q for their gut bacteria, whether these two biotypes are differed with each other. Gut bacterial strains isolated by standard surface sterilization method was identified through 16S rRNA gene sequence. Gut bacterial strains of B. tabaci biotypes B and Q and their close relatives retrieved from the public database (NCBI) indicated that the biotype B was less diversified only with four genera viz., Bacillus, Micrococcus, Pseudomonas and Staphylococcus, whereas the biotype Q diversified with six such as Bacillus, Janibacter, Micrococcus, Staphylococcus, Stenotrophomonas, and Streptomyces. Results of the present investigation suggesting that there may be a relationship with gut bacterial strains and susceptibility to insecticides and host plant preference of B. tabaci biotype B and Q.
        25.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to investigate the effect of doping C, N, B and F elements on TiO2 for reducing the band gap, the heat treatment of TiO2 was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase TiO2 was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of TiO2 with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on TiO2 for reducing the band gap effectively.
        4,000원
        26.
        2008.05 구독 인증기관·개인회원 무료
        A cysteine- rich protein encoded by Cotesia plutellae bacovirus (CpBV) was identified in the parasitized Plutella xylostella. The gene, called CpBV-CRP, encodes 189 amino acids with a signal peptide of 20 residues at N-terminus determined by bioinformatic analysis, suggesting a secretory protein. High CpBV-CRP expression in the parasitized P. xylostella was observed at early days after parasitization and decreased with the course of parasitization. Expression of CpBV-CRP was tissue-specific in the fat body/epidermis, but not in hemocyte and gut. Its physiological function was analyzed by transient expression of a CpBV segment containing CpBV-CRP. The treated larvae underwent an immunosuppression in terms of hemocyte-spreading behavior. When the treated larvae were also co-injected with dsRNA against CpBV-CRP, the suppressed hemocyte behavior was significantly recovered. This study reports a cysteine-rich protein encoded in CpBV genome and its physiological function to be an immunosuppressant.
        28.
        2005.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanoscale Al powder with thin layer of alumina was produced by Wire Electric Explosion (WEE) process. Spark-Plasma Sintering (SPS) was performed for the produced powder to confirm the effectiveness of SPS like so-called 'surface-cleaning effect' and so on. Crystallite size and alumina content of produced powder varied with the ratio of input energy to sublimation energy of Al wire (): Increase in () resulted in the decrease of crystallite size and the increase of alumina content. Shrinkage curve during SPS process showed that the oxide surface layer could not be destroyed near the melting point of Al. It implied that there was not enough or no spark-plasma effect during SPS for Al/Alumina powder.
        4,000원
        31.
        2003.06 구독 인증기관·개인회원 무료
        1. The oxidation resistance of containing Ni-base alloy is superior to that of the alloy without . 2. The appearance of oxides of Ni-20Cr-20Fe-5Nb- alloy is similar to that of oxides in commercial PM1000 and MA754 alloy. 3. The oxides in ODS alloy are grown mainly at particle boundaries.
        32.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        A space plasma facility has been operated with a back-diffusion-type plasma source installed in a mid-sized vacuum chamber with a diameter of ~1.5 m located in Satellite Technology Research Center (SaTReC), Korea Advanced Institute of Science and Technology (KAIST). To generate plasma with a temperature and density similar to the ionospheric plasma, nickel wires coated with carbonate solution were used as filaments that emit thermal electrons, and the accelerated thermal electrons emitted from the heated wires collide with the neutral gas to form plasma inside the chamber. By using a disk-type Langmuir probe installed inside the vacuum chamber, the generation of plasma similar to the space environment was validated. The characteristics of the plasma according to the grid and plate anode voltages were investigated. The grid voltage of the plasma source is realized as a suitable parameter for manipulating the electron density, while the plate voltage is suitable for adjusting the electron temperature. A simple physical model based on the collision cross-section of electron impact on nitrogen molecule was established to explain the plasma generation mechanism.
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