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        검색결과 186

        61.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        in vitro studies on salt torerance was carried out with Salix gracilistyla. Shoot growth of plants treated with NaCl showed statistically significances among different levels of concentration(0~200 mM) on 1/2MS medium. Plant growth was not grown at in higher concentration than 75 mM and plants were dead over 150 mM Nacl Browned leaf was observed from 14 days at higher concentration than then 75 mM NaCl, and chlorophyll content was dramatically decreased. Main roots and rootlet in same concentrates(75 mM) or high NaCl treatment were changed the color to black. The proline and sugar contents were dramatically increased in the higher than 75 mM NaCl treatments after 14 - 15 days. To determine NaCl and minerals in salt stressed plants, leaf, stem and root of in vitro plant were subjected to ICP analysis. Na content was increased with culture days in all three parts. These results suggest that S. gracilistyla can be used vegetative restoration in coastal wetlands reclaimed.
        4,000원
        63.
        2017.04 구독 인증기관·개인회원 무료
        The diamondback moth (DBM), Plutella xylostella, is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. Chlorantraniliprole is the first commercial insecticide that belongs to the new chemical class of diamide insecticides. In this study, the resistant strain was observed 1578-fold resistance to chlorantraniliprole. Point mutation (G4946E) in ryanodine receptor (RyR) showed a high frequency. Enzyme assays indicated that glutathione S-transferase (GST) activity in the resistant strain was 2.4 times higher compared with the susceptible strain, whereas no difference was seen for P450 and esterase. In addition, the expression of two GSTs genes was up-regulated. These findings pave the way for the complete understanding of the mechanisms of diamide insecticides resistance in insects.
        64.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was determined optimal condition as culture medium, pH, carbohydrate source and growth regulators through axillary buds cultures of Salix gracilistyla. S. gracilistyla shoots were obtained from axillary bud on 1/2MS basal medium after 2 weeks of culture. Highest shoot growth was showed in the MS medium(GI= 2.43). Shoot growth was highest in 9% sucrose compared to other concentration. BAP affects axillary shoot multiplication in of S. gracilistyla. Among nutrients, Ca2+ was not affected shoot number of S. gracilistyla. However, NH4+, NO3 -, and K+ is greatly influenced shoot number. However, Ca2+ was affected in shoot length of S. gracilistyla. Feeding of Mg2+ was not affected in shoot length. Root number is greatly influenced by NH4 +, NO3 -, and K+, however NH4 + and K+ was not affected root number of S. gracilistyla. NH4 + was affected root length, however Mg4 + was not affected root length. Treatment of 0.1mg/L IBA promoted in vitro rooting. In vitro rooted plantlets were successfully transferred to pots for 4weeks hardening process. Later, these plants were transferred to soil with above 90% survival rate in BS+SD(2:1). These results could be easily adopted for commercial large scale cultivation.
        4,600원
        66.
        2016.10 구독 인증기관·개인회원 무료
        Euzophera batangensis (Lepidotera: Pyralidae) is seriously damaging trunks or branches of persimmon tree (Diospyros sp.). We tested the attractiveness of (Z)-9-tetradecen-1-ol (Z9-14OH) and (Z9,E12)-tetradeca- 9,12-dien-1-ol (Z9,E12-14OH) with single or blended baits at southern parts of Korea in 2014 and 2015. The monoene was not attractive at all at three places during the two years. In 2014, diene was equally or more attractive than the mixture in Jinju and Suncheon, respectively. In 2015 too, the attractiveness of diene and mixture was not different in Jinju and Munsan. Monitoring of the seasonal occurrence of E. batangesis with the sex pheromone components revealed that it occurred three times a year; the first occurrence from early April to mid May, the second from early Jun to mid July, and the third from late August to late September.
        67.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A powder injection molding process is developed and optimized for piezoelectric PAN-PZT ceramics. Torque rheometer experiments are conducted to determine the optimal solids loading, and the rheological property of the feedstock is evaluated using a capillary rheometer. Appropriate debinding conditions are chosen using a thermal gravity analyzer, and the debound specimens are sintered using sintering conditions determined in a preliminary investigation. Piezoelectric performance measures, including the piezoelectric charge constant and dielectric constant, are measured to verify the developed process. The average values of the measured piezoelectric charge constant and dielectric constant are 455 pC/N and 1904, respectively. Powder injection molded piezoelectric ceramics produced by the optimized process show adequate piezoelectric performance compared to press-sintered piezoelectric ceramics.
        4,000원
        68.
        2016.04 구독 인증기관·개인회원 무료
        Oxalic acid has a nematicidal activity against the root-knot nematode Meloidogyne incognita. High producer of oxalic acid was isolated, and then named as Aspergillus niger F22. Oxalic acid production was investigated under various temperatures from 20 – 33oC and rotational speeds in 5 L jar fermenters. Yield of oxalic acid increased with decreasing temperature. The highest yield was obtained at 23oC, showing the yield of oxalic acid of 8.7 g/L, whereas oxalic acid production was least at 33oC. At 20oC, the yield was lower than that of 23oC. At a rotational speed of 300 rpm, serious oxygen depletion was present from 48 - 72 h, resulting in low productivity of 26.2 mg /L·h. When a rotational speed was set at 600 rpm, dissolved oxygen tension was over 40% and oxalic acid production increased up to approximately 55%. Viscosity during the culture differed with temperatures. Viscosity increased with the increment of temperatures. When A. niger F22 was cultured at 23oC, viscosity was 810 cP, which was favorable for oxalic acid production.
        69.
        2016.04 구독 인증기관·개인회원 무료
        Biological control has been tried for integrated pest management. It is often comparable, safe, and environment-friendly, making itself an alternative for chemical agents. Filamentous microorganisms, i.e., fungi and streptomystes, produce many kinds of useful metabolites, and some of them have been developed as a biocontrol agent. However, they still have a long way because of the concern of manufacturing cost. Therefore, process development was intensively studied to meet cost-effectiveness. Operating conditions of bioreactor, e.g., agitation and aeration, had an effect on biological and physiological responses such as mycelial morphology, oxygen and nutrient transfer. Understanding relationship between operating parameters and microbial responses in terms of growth, substrate and oxygen consumption, and production yield was critical for process development. This study dedicated to build strategies for mass production of biological control agent using aerobic filamentous microorganisms.
        71.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to examine relationship between stroke patients' degree of satisfaction with leisure and quality of life according to their leisure activity types and whether they conducted leisure activities. A direct survey was performed from April 8 to May 3, 2013 on 92 inpatients and outpatients who received occupational therapy at hospitals located in Jeonju and Gunsan. A frequency analysis was carried out in order to look at the general characteristics of the subjects, their degree of participation in leisure activities, and their degree of satisfaction with leisure activities. A Pearson's coefficient was used to examine relationship between their degree of satisfaction and quality of life according to participation in leisure activities. Their degree of satisfaction according to participation in leisure activities was significantly higher when they took part in leisure activities such as handicraft activities, sports activities, or travel or tourism activities than when they did not perform any leisure activities. Their quality of life according to participation in leisure activities was higher when they conducted sports activities, outing activities, or tourism activities than when they did not. There was significant correlation between their degree of satisfaction with leisure and quality of life according to leisure activities.
        4,000원
        72.
        2014.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Despite a large amount of research on reading, little attention has been paid to experimental studies on the effects of purposeful reading. This study explored the effects of reading purpose on reading comprehension and perceived difficulty. 71 high school students participated in this study and were randomly assigned to three groups – graphic organizer (Purpose 1), key sentence (Purpose 2), and control. The learners’ reading comprehension was measured through pre-, post- and delayed tests. The participants’ perceived difficulty for the texts was also checked with a sevenpoint Likert scale. The result demonstrates no immediate effect of establishing reading purpose, though immediate reading purpose effects might be found if a longer treatment period is set. The results also reveal the sustained effect of reading purpose on reading comprehension. In perceived text difficulty, the Purpose 1 group found the reading passages the easiest among the three groups. This suggests that learners establishing a reading purpose can gain greater ease in reading than those without a reading purpose.
        5,400원
        73.
        2014.04 구독 인증기관·개인회원 무료
        The legume family (Fabaceae) is the third largest family of flowering plants worldwide and often damaged by stink bugs, particularly Riptortus clavatus Thunberg (Heteroptera: Alydidae). This insect selectively feeds and oviposits on these plants, resulting in >50% of damage to soybeans harvested in autumn. The most common control methods for this insect are periodic application of chemical pesticides, pheromone traps, and bait crops, but still they encounters residual problem, insect resistance or low control efficacy. The current management system needs alternative control methods, which possibly combined with the present methods. Some entomopathogenic fungi have high virulence against the nymphs and adults of R. clavatus in a favorable conditions, reaching ∼80% mortality with mycosis in 3∼5 days. The genera of Beauveria and Metarhizium are possible control agents for effective and safe management of the serious pest. Fungal infection in R. clavatus was observed using an egfp-expressing fungal transformant. Thermotolerant entomopathogenic fungal conidia can be produced in cereal substrates, which enables conidia to be stable for long times. Our considerations need to be given to the combinations with other control methods, such as chemical pesticides or pheromone trap.
        74.
        2012.10 구독 인증기관·개인회원 무료
        Among hemipteran insects which is the most important insect vector of plant viruses, small brown planthopper, Laodelphax striatellus, transmits the rice stripe virus (RSV) causing rice stripe disease. For effective control of RSV, it is important to understand interaction between RSV and L. striatellus. Therefore, in this study, expressed sequence tag (EST) databases were generated based on 454 GS-FLX pyrosequencing for comparative transcriptome analysis between nonviruliferous and RSV-viruliferous L. striatellus. By comparing the two EST libraries, we showed that 108 host genes were significantly up-regulated and 28 host genes were significantly down-regulated in viruliferous insects. Interestingly, genes encoding ribosomal proteins were mainly up-regulated in viruliferous L. striatellus, whereas genes related to translation were concentrated in the downregulated cohort. These RSV-dependently regulated genes may have important function in the behavior of planthopper or the transmission of RSV.
        75.
        2012.10 구독 인증기관·개인회원 무료
        Bacillus thuringiensis serovar mogi of a novel serogroup (H3a3b3d), which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the B. thuringiensis serovar mogi contained only megaplasmid (> 30 MDa) on which the toxin genes were occasionally located. Sequence analysis using 454-pyrosequencing revealed that the megaplasmid harbored at least seven putative cry genes, showing about 84%, 75%, 73%, 58%, 84%, 39% and 75% similarities in amino acid sequences with Cry27Aa, Cry19Ba, Cry20-like, Cry56Aa, Cry39ORF2, Cry8Ba and Cry40ORF2, respectively. These cry genes were cloned to the Escherichia coli-B. thuringiensis shuttle vector, pHT1K, and then introduced into an acrystalliferous B. thuringiensis Cry-B strain for further molecular characterization. To investigate the role of these genes in crystal production, the expression profiles of these toxin genes were analyzed by quantitative real-time PCR (qrtPCR) from the wild type strain as well as transformant strains. The results clearly indicate that the cry39orf2 was the dominant ingredient in the crystal. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, could be used as a good resource for studying unknown mosquitocidal cry genes.
        76.
        2012.10 구독 인증기관·개인회원 무료
        The baculovirus expression system is one of the most popular methods used for the production of recombinant proteins but has several complex steps which have proved inherently difficult to meet a multi-parellel process. We have developed a novel recombinant bacmid, bEasyBm that enabling easy and fast generation of pure recombinant virus without any purification step. In the bEasyBm, attR recombination sites were introduced to facilitate the generation of recombinant viral genome by in vitro transposition. Moreover, extracellular RNase gene from bacillus amyloliquefaciens, barnase, was expressed under the control of Cotesia plutellae bracovirus early promoter. Therefore, only when the barnase gene was replaced to gene of interest, the bEasyBm could replicate in host insect cells. When the bEasyBm was transposed with pDualBac-EGFP and pDualBac-LUC respectively, there were no non-recombinant backgrounds were detected from unpurified BmEasy-EGFP or BmEasy-LUC stocks. In addition, the resulting recombinant virus, BmEasy-EGFP, showed comparable level of EGFP expression efficiency with the plaque-purified recombinant virus, BmEGFP, which was constructed using bBmGOZA system. Based on these results, high-throughput condition for generation of multiple recombinant viruses in a time was established.
        77.
        2012.10 구독 인증기관·개인회원 무료
        Varieties of Bacillus thuringiensis (Bt) crystal proteins, Cry proteins, have so far been found as one of the most successful biological control agents which are safe to natural environments for a long time. Recently, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, through the 3D structure prediction and accompanying mutagenesis study for the Mod-Cry1Ac, 7 and 16 amino acid residues from domain I and II, respectively, responsible for its insecticidal activity against larvae of Spodoptera exigua and Ostrinia furnacalis were identified. To construct novel cry genes with improved insecticidal activity, we randomly mutated these 23 amino acid sequences by in vitro muti site-directed mutagenesis, resulting in totally 24 mutant cry genes. For further characterization, these mutant cry genes were expressed as a fusion protein with polyhedrin using baculovirus expression system. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. In the further study, we plan to investigate their insecticidal activity against Plutella xylostella, S. exigua and O. furnacalis larvae.
        78.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Meedon rice varieties are important for local adaptability, grain quality and market availability, and have been grown in Myanmar for centuries. Because of temporal variability and spatial heterogeneity, Meedon rice varieties in rainfed lowland areas may be diverse. However, information on diversity of Meedon rice germplasm is limited. This study was carried out to assess genetic diversity and to analyze population structure of Meedon rice germplasm conserved in Myanmar Seed Bank using SSR markers. For assessing genetic diversity, 154 accessions of Meedon rice germplasm were analyzed with nine SSR markers. A total of 86 alleles were detected with an average of 9.6 alleles per locus. All the loci were found to be polymorphic, and there were considerable genetic variation among accessions with mean values of expected heterozygosity (HE) = 0.5774 and polymorphic information content (PIC) = 0.5496. High frequency of rare alleles was identified, among which 35 unique (accession-specific) alleles were observed. Based on cluster analysis, rice accessions were mainly clustered into two groups, and as a result of model-based analysis, two distinct genetic populations and an admixture were classified. This result indicated that SSR markers have proved to be useful markers for detecting genetic diversity in Meedon rice, and the occurrence of a considerably high number of rare and unique alleles in the germplasm indicates their potentiality as a reservoir of rare genotypes for use. Unique alleles are also important because they may be diagnostic of a particular type of genotype for identification.
        4,000원
        79.
        2012.06 구독 인증기관·개인회원 무료
        Neural stem cells (NSCs) are self-renewing tripotent cell populations and have capacity of neuronal (neurons) and glial (astrocytes and oligodendrocytes) differentiation. Many researchers have reported that NSCs have therapeutic effects in neurological disease by transplantation. However, it is not easy to obtain NSCs in vitro. Recently, Yamanaka and colleagues showed that somatic cells could be reprogrammed into pluripotent state by enforcing reprogramming factors. Induced pluripotent stem (iPS) cells undergo unlimited self-renewal and have differentiation potential into various types of cells like embryonic stem cells. Direct differentiation into a specialized cell types from iPS cells hold considerable promise for regenerative medicine as well as basic research. Here, we induced differentiation of iPS cells into NSCs in vitro and in vivo, which were compared with embryonic stem (ES) cell-derived NSCs and brain derived NSCs. NSCs from ES and iPS cells were morphologically indistinguishable from brain derived NSCs and stained positive for NSCs markers Nestin and Sox2. ES cells derived NSCs were transcriptionally distinguishable from brain derived NSCs. However, global gene expression pattern were similar but distinct between iPS derived NSCs and brain derived NSCs. Moreover, iPS derived NSCs were spontaneously aggregated upon passaging, formed ES cell like colonies, and finally reactivated Oct4-GFP. The spontaneously reverted GFP-positive cells (iPS-NSC-iPS) expressed similar levels of pluripotency markers (Oct4,Nanog) to ES and iPS cells, and could form germ line chimera. One possible explanation for this phenomenon is that spontaneously re-reprogramming was associated with transgene re-activation when iPS cells were differentiated into NSCs. However, NSCs from dox-inducible iPScells could not be reprogrammed into pluripotent state without doxycycline. Taken together, iPS derived NSCs were morphologically and similar to brain derived NSCs, but differ in gene expression pattern and maintenance. * This work was supported by the Next Generation Bio-Green21 Program funded by the Rural Development Administration (Grant PJ008009).
        80.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        꼬마배나무이 (Cacopsylla pyricola)에 저항성 품종육성을 위한 육종재료를 선발코자 월동형 성충수, 단과지내의 산란수, 과총엽내의약충수 및 수관 전체적인 그을음 발생정도를 15개 종 및 종간잡종133개 유전자원을 대상으로 조사하였다. 월동형 성충수는 Pyrus.calleryana 4.6마리, 단과지내 산란수는 P. calleryana 0.3개, 과총엽내약충수는 P. calleryana 0마리, 그리고 그을음 발생정도는 P.betulaefolia, P. calleryana, P. communis, P. hybrid (P.pyrifolia × P.communis), P. lindleyi 0으로 발생 및 피해정도가 가장 낮았으며 종간의 차이가 뚜렷하였다. 전체적으로 대목으로 이용하고 있는 콩배인P. calleryana와 P. betulaefolia가 조사 대상 유전자원 중 가장 높은 항객성(antixenosis)을 보였으나 품질개량에 많은 기간이 요구됨에 따라 실용적으로는 서양배(P. communis) 중 ‘Conference', 'Cascade','Bosc', 'Winter Nelis' 가 가장 낮은 발생 및 피해정도를 보여 꼬마배나무이 저항성 품종 육성을 위한 좋은 육종재료로 판단되었다.
        4,000원
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