검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 2,998

        1881.
        2008.10 구독 인증기관·개인회원 무료
        Molecular mechanisms of monocrotophos resistance in the two-spotted spider mite (TSSM), Tetranychus urticae Koch, were investigated. The resistant (AD) strain showed ca. 3,565-fold resistance compared to a susceptible (UD) strain. No significant differences in the esterase and gluthathion-S-transferase activities were found between two strains whereas AD showed a 1.9-fold higher mixed function oxidase activity. Acetylcholinesterase (AChE) inhibition assay revealed that the AChE from AD strain is 91-fold less sensitive to monocrotophos, suggestive of the target site insensitivity mechanism. Three point mutations (G228S, A391T and F439W/Y) in the AChE gene (tssmace) appeared to primarily contribute to the reduced sensitivity of AChE as judged by the correlation study of mutation frequency versus resistance levels (LC50) of several field populations. The resulting correlation coefficients of the G228S and F439W mutations were 0.711 and 0.300, respectively, suggesting that G228S mutation may play a more significant role in resistance. The A391T mutation, saturated in all field populations examined, appears to provide a base line resistance.
        1882.
        2008.10 구독 인증기관·개인회원 무료
        Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae) is one of the most important predators of spider mites in Japan. Various characteristics have been studied in this species. However, because there is a lack of genetic markers, genetic diversity within and among populations has not been well elucidated. Microsatellites, short stretches of tandem-repeated 1- to 5- nucleotide sequences, are ubiquitously present in eukaryotic genomes and are highly polymorphic. Their high polymorphism makes them suitable markers for studying intra-specific variation. In this study, we developed microsatellite markers in N. womersleyi, and then examined genetic diversity in their populations. Microsatellite enriched genomic DNA library was contracted and sequenced from a single female adult. Of the 40 plasmids sequenced, 31 plasmids showed microsatellite sequences and 24 plasmids were unique. Finally, we could design primers on three loci. When tested their diversity on one wild and two laboratory populations, five to 18 alleles were detected. The wild population showed highest genetic diversity, and this divergence decreased in rearing populations. To investigate the effects of different rearing conditions, genetic diversity in two rearing populations, which were different in population size, were compared with those in the original wild populations. The allelic richness and gene diversity were not significantly different between wild and large-size populations, while the values were significantly decreased in small-size populations. Thus, 40 to 60 females per generation was sufficient to conserve the genetic diversity in N. womersleyi populations during laboratory rearing. In conclusion, the microsatellite markers developed were useful to evaluate genetic diversity in wild and laboratory populations of N. womersleyi.
        1883.
        2008.10 구독 인증기관·개인회원 무료
        A new species of Adoxophyes is described, illustrated, and distinguished from closely resembling species. Larvae of this species were discovered on sweet cherry (Prunus avium) imported from China and intercepted under plant quarantine inspection at Korean sea- and airport. They were reared to adult in the laboratory for identification. We provide a full description of the new species based on adult of female external structures. In addition, we conducted a comparative study of three related species (A. orana, A. honmai, and A. new species) and provided a key to distinguish them. To confirm the identity of new species, we compared barcoding sequences (~472 bp) of the mitochondrial cytochrome c oxidase subunit I (COI) gene from 11 specimens of three Adoxophyes species. As a result of this study, we confirmed the identity of Adoxophyes new species. We also provided pairwise p-distances among the species and their neighbor-joining tree.
        1884.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the pyrimidine derivatives were obtained in low yields ranging from 8% to 20%, we reported the successful preparation of N,N-diaryl-pyrimidin-2-amine derivatives starting from the corresponding 2-aminopyrimidines (1a-1c), by direct palladium-catalyzed arylation using different arylbromides. The reasons of low yields are thought to be the electronic and steric effects by the neighboring aromatic systems. The absorption spectra and photoluminescent spectra of compounds (3a 3g and 4a-4c) were measured using dichloromethane on the concentration of 25 mM by UV vis spectroscopy and luminescent spectroscopy. Pyrimidine derivatives 4a, 4b, and 4c showed moderate emission maxima at 474 nm, 481 nm, and 367 nm, respectively, while other compounds showed very weak photoluminescence or no photoluminescence at all.
        4,000원
        1885.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous carbon materials synthesized from various plant derived precursors i.e. seeds of [Castor (Ricinus communis), Soap nut (Sapindus sp.), Cashew-nut (Semecarpus anacardium), Jack fruit (Artocarpus heterophyllus), Safflower (Carthamus tinctorius), Ambadi (Crotolaria juncea), Neem (Azadirachta indica), Bitter Almond (Prunus amygdalus), Sesamum (Sisamum indicum), Date-palm (Phoenix dactylifera),Canola (Brassica napus), Sunflower (Helianthus annulus)] and fibrous materials from [Corn stem- (Zea mays), Rice straw (Oryza sativa), Bamboo (Bombax bambusa) and Coconut fibers (Cocos nucifera)] were screened to make supercapacitor in 5M KOH solution. Carbon material obtained from Jack fruit seeds (92.0 F/g), Rice straw (83.0 F/g), Soap nut seeds (54.0 F/g), Castor seeds (44.34 F/g) and Bamboo (40.0 F/g) gave high capacitance value as compared to others. The magnitude of capacitance value was found to be inversely proportional to the scan rate of measurement. It is suggested that carbon material should possess large surface area and small pore size to get better value of capacitor. Moreover, the structure of carbon materials should be such that majority of pores are in the plane parallel to the plane of electrode and surface is fluffy like cotton ball.
        4,000원
        1886.
        2008.06 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the potential hazardous effects of sorting process by flowcytometry on the quality of boar spermatozoa by flowcytometer. Freshly collected boar semen was diluted and divided into two groups; control none sorted and sorted. Sperms in sorted group were processed with flowcytometer for cell sorting with 100 uM nozzle under the 20 psi pressure. Measurements on each parameter were made at two time points, 0hr (right after sorting) and 24 hr post sorting. Although there was a tendency of lower viability in sorted group than none sorted control group, the percentage of live cells in control(75.83+-6.92 & 59.53+-10.34) was not significantly different from sorted (59.7+-7.34 & 43.97+-3.76) at both 0 and 24 hr post sorting. However, sorted sperm showed significantly lower mitochondrial function compared to the control at both 0 h (79.37+-3.22 vs. 63.50+-10.05) and 24hr(67.27+-3.22 vs. 46.97+-5.37) time points (p<0.007). Sperm DNA fragmentation rate was significantly lower in control (22.0+-7.04) than that of sorted (32.27+-7.49) at 24 hr time point (p<0.0002). Taken together, these data suggested thatsorting process by flowcytometer may have influenced sperm motility rather than viability. Also high speed sperm sorting by flowcytometer has significant effects on DNA fragmentation on elapsed time after sorting.
        3,000원
        1890.
        2008.05 구독 인증기관·개인회원 무료
        A quantitative sequencing (QS) protocol that detects the frequencies of sodium channel mutations (M815I, T917I and L920F) responsible for knockdown resistance in permethrin-resistant head lice was tested as a population genotyping method. Genomic DNA fragments of the sodium channel α-subunit gene that encompass the three mutation sites were PCR-amplified from individual head lice with either resistant or susceptible genotypes, and combined together in various ratios to generate standard DNA template mixtures for QS. Following sequencing, the signal ratios between resistant and susceptible nucleotides were calculated and plotted against the corresponding resistance allele frequencies. Quadratic regression coefficients of the plots were close to 1, demonstrating that QS is highly reliable for the prediction of resistance allele frequencies. Prediction of resistance allele frequencies by QS in several globally collected lice samples including 12 Korean lice populations suggested that permethrin resistance varied substantially amongst different geographical regions. Three local populations of Korean lice were determined to have 9.8-36.7% resistance allele frequencies, indicating that an urgent resistance management is needed. QS should serve as a preliminary resistance monitoring tool for proper management strategies by allowing early resistance detection.
        1891.
        2008.05 구독 인증기관·개인회원 무료
        Four species in two genera of the tribe Pilophorini, the ant mimetic Plant bugs are revised from Nepal. One new species of genus Pilophorus Hann, P. sp. nov is proposed. Pilophorus typicus (Distant, 1909) and Sthenaridea piceonigra (Motschulsky, 1863) are new record to Nepal. Pilophours josifovianus Duwal and Yasunaga, 2008 previously described species from Nepal and all other three species are here with illustrations of male and female genitalia and their biological information.
        1900.
        2008.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spectral line profiles of filaments/prominences to be observed by the Fast Imaging Solar Spectrograph (FISS) are studied. The main spectral lines of interests are Hα Ca II 8542, and Ca II K. FISS has a high spectral resolving power of 2 x 105, and supports simultaneous dual-band recording. This instrument will be installed at the 1.6m New Solar Telescope (NST) of Big Bear Solar Observatory, which has a high spatial resolution of 0.065" at 500nm. Adopting the cloud model of radiative transfer and using the model parameters inferred from pre-existing observations, we have simulated a set of spectral profiles of the lines that are emitted by a filament on the disk or a prominence at the limb. Taking into account the parameters of the instrument, we have estimated the photon count to be recorded by the CCD cameras, the signal-to-noise ratios, and so on. We have also found that FISS is suitable for the study of multi-velocity threads in filaments if the spectral profiles of Ca II lines are recorded together with Hα lines
        4,000원