검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 41

        21.
        2018.10 구독 인증기관·개인회원 무료
        Longhorned tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) in human. The tick occurs in mostly grass fields, and the use of pyrethroid insecticides induced pest resistance and environmental residual toxicity. Particularly the use of chemicals near residential areas where persons live become a big issue, so environmentally safe control agents need to be considered. Here in this work, our interest was given to the selection of highly virulent fungi against H. longicornis. A total of 101 fungal pathogens collected from mountainous areas were assayed by a dipping the nymph stage of ticks into a conidial suspension (1×107conidia/ml). Interestingly among several species, one species showed high virulence and mycosis were observed in 7-15 days. Most of the selected isolates produced a large amount of conidia in Italian millet, rice and millet with thermotolerance at 40-45°C. Based on these results, we selected a couple of isolates with high virulence against H. longicornis and they could be used for the control of the ticks after the set-up of a practical application strategy in fields by optimizing fungal colonization in soil and phyllosphere.
        22.
        2018.10 구독 인증기관·개인회원 무료
        Thrips is one of the serious insect pests in many economic crops, in which general managements rely mainly on chemical insecticides. However, the overuse of chemicals led to the development of insect resistance and environmental residual issues. Therefore, thrips management requires the consideration of alternative strategies which are less harmful to the environment and working on different target points. In this work, we isolated entomopathogenic fungi from soil, and identified them with morphological and molecular biology methods, followed by a preliminary virulence assay against Tenebrio molitor larvae. Selected fungal isolates were adjusted to 1×107 conidia/ml for an indoor virulence assay against thrips adults, and highly virulent isolates were added to a thrip-pathogenic fungal library. Biological characteristics of efficacious isolates were investigated comparing to a previously commercialized fungal isolate. This entomopathogenic fungal library could be used as a valuable resource for developing effective strains to control thrips in agricultural fields.
        23.
        2018.10 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been known as promising candidates for biological control of insect pests. Recently, researchers consider the fungal thermotolerance in formulations and field applications. In this study, we investigated the production of thermotolerant Isaria javanica and I.fumosorosea conidia through grain-based solid cultures and exposure to light stress. As results, of the ten grain substrates, Italian millet, rice, perilla seed and sesame, rice, sorghum produced highly thermotolerant conidia in the strains. The two strains were exposed to a light stress and showed enhanced thermal stability compared to control, when exposed to 45°C for 2 hours. This work suggests that heatresistant entomopathogenic fungal conidia can be produced by grainbased solid cultures and exposure to light stress.
        24.
        2018.10 구독 인증기관·개인회원 무료
        Whitefly has a broad host range of more than 600 species, and 40 biotypes have been reported worldwide. Among the various ecological types, B and Q are the most problematic. Especially, Biotype Q, which causes serious damage in the green house, mediates more than 40 kinds of viruses, including Tomato yellow leaf cull virus (TYLCV). The development of resistance to whitefly, adverse effects on non-target organisms, and strengthened legal regulations are making chemical control difficult in application. For these reasons, the use of alternative strategies is needed to suppress the Biotype Q whitefly population. Entomopathogenic fungi were investigated and developed to control hard-control insect pest, such as whitefly. These fungi are natural pathogen of their invertebrate host and contribute to the regulation of their host population in the environment. In addition, these agents are typically harmless to humans and non-targeted organisms and do not adversely impact the environment. Therefore, in this study, we screened pathogenic fungi against whitefly using our entomopathogenic fungal library, and virulence tests were conducted with conoidal suspension (1×107conidia/ml) in laboratory conditions. As a result, 10 isolates showed 80-100% mortality at 5 days after treatment. We will analyze the characteristics of these fungal isolates and evaluate their potential as insecticides against whitefly. The selected isolates against the high mortality of whiteflies can be effectively used in integrated pest management programs for whiteflies.
        25.
        2018.10 구독 인증기관·개인회원 무료
        Japanese pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is considered as a serious pest in pine trees. To develop an eco-friendly strategy to manage this forest insect, we collected entomopathogenic fungi from Korean soil and assessed their virulence against the adults of the insect in laboratory conditions. As a result, two isolates with conidial suspension (1.0×107conidia/ml), showed 87% and 90% mortality 12 days after fungal treatment, respectively. We assessed the potential of the fungi-derived destruxin and protease as additives to the fungal isolates, and they showed insecticidal activity via feeding and spraying treatments. Finally, we produced fungal conidia in massive solid cultures and formulated wettable powders, and now studying optimal conditions of oil-based formulation with two isolates. Based on these results, we are evaluating the control efficacy of the fungal agents against M. alternatus in field conditions.
        26.
        2018.04 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in forest is considered as a serious forest pest in pine trees. In this study, we collected entomopathogenic fungi from soil and assessed their virulence against the adults of the inset using a spray method in laboratory condition. Two entomopathogeinc fungi isolates showed high virulence against the adults. In the concentration of 1.0 × 107conidia/ml, the mortality rate of the adults were 53% and 60%. In semi-field condition, one isolate showed a virulence of 60% against the adult. Consequently, we confirmed the possibility of the fungal isolates in controlling the beetles. In near the future, we will investigate several factors which is possibly related to the control of the forest insect pest using entomopathogenic fungi in field conditions, given the importance of fungal formulation and practical application methods.
        27.
        2018.04 구독 인증기관·개인회원 무료
        The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest. Therefore, this study provides a screening method to select entomopathogenic fungi, having high virulence against H. longicornis. The virulence test was conducted by dipping method with a conidial suspension (1×107 conidia/ml). As a result, cadavers of H. longicornis infected with entomopathogenic fungi were obtained by this method. Based on this results, we selected several isolates having high virulence to H. longicornis. We suggest that, selected isolates in this study can be used for the control of H. longicornis.
        28.
        2018.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been known as promising candidates for biological control of insect pests. Recently, researchers consider the fungal thermotolerance in formulations and field applications. In this study, we investigated the production of thermotolerant Isaria javanica and I.fumosorosea conidia through grain-based solid cultures and exposure to light stress. As results, of the ten grain substrates, Italian millet, rice, perilla seed and sesame, rice, sorghum produced highly thermotolerant conidia in the strains. The two strains were exposed to a light stress and a heat stress. And they showed enhanced thermal stability compared to control, when exposed to 45°C for 2 hours. This work suggests that heat-resistant entomopathogenic fungal conidia can be produced by grain-based solid cultures and exposure to light stress.
        29.
        2018.04 구독 인증기관·개인회원 무료
        Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) is a serious insect pest of various crops in the world. The management of this pest mainly have relied on chemical agents. However, the overuse of chemical agents for long times causes insect resistance, and negative effects on environment. Therefore, alternative control methods, such as biological control, that are less harmful to the environment and have different mode of action are needed to control this pest. In this study, we isolated entomopathogenic fungi from Korean soil, and characterized them via morphological and molecular identifications and pathogenicity check against Tenebrio molitor larvae. The isolated fungi were subjected to virulence assay against T. Palmi with a conidial suspension of 1×107 conidia/ml in laboratory conditions. This entomopathogenic fungi library would be a good resource to select effective strains for the control of T. palmi in fields.
        30.
        2018.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi play an important natural role in regulating their insect host populations, and their ecology was also associated with plant and soil. These microorganisms have been living by reacting to insect, plant and environmental factor. The advanced bioinformatics technology such as next-generation sequencing and RNA sequencing has revolutionized in understanding of entomopathogenic fungi. Recently studies provided a lot of information on evolutionary relationships and virulence-related characteristics. We are starting to know where these microorganisms from is, and how they live in nature. The bioinformatics technology will give us further our understanding of the natural roles of these fungi in nature.
        31.
        2017.10 구독 인증기관·개인회원 무료
        The entomopathogneic fungal colonization has become an interesting issue in ecological pest management. Plant-orientedfungi induce plant growth promotion and act as natural control agents against insect pest. Herein this work, we evaluatedthe ability of fungal colonization on bark, branches and leaves of pine tree (Pinus densiflora) to select optimal candidatesfor controlling Japanese pine sawyer (Monochamus alternatus), which is the pine wilt disease vector in Korea. As a result,some Beauveria and Metarhizium isolates could colonize on the substrates of P. densiflora and showed pathogenicity againstM. alternatus. This result suggests that the selected entomopathogenic fungi are possibly candidates for long-term managementof M. alternatus in pine tree forest.
        32.
        2017.10 구독 인증기관·개인회원 무료
        The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopeniasyndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest.We evaluated three bioassay methods, such as spray, dipping and dropping. As a result, the dipping method was themost efficient way to measure the fungal virulence. Finally, we constructed a Haemaphysalis longicornis pathogenic fungallibrary to further facilitate the resources to be used as potential biological control agents. A conidial suspension of 1×107conidia/ml was exposed to the ticks by dipping. We confirmed that some isolates were highly virulent to the ticks. Thisresults indicated that some fungi could be used to effectively control the Haemaphysalis longicornis.
        33.
        2011.05 구독 인증기관·개인회원 무료
        The leaf beetle, Chrysolina aurichalcea (Coleoptera: Chysomelidae), is a pest damaging plants of Compositae. In order to understand the genetic diversity and geographic variation of the species we sequenced a portion of mitochondrial COI gene (658 bp) and complete nuclear internal transcribed spacer 2 (ITS2) collected from seven Korean localities. A total of 18 haplotypes (BARCA01 ~ BARCA18), with the maximum sequence divergence of 3.04% (20 bp) were obtained from COI gene sequence, whereas 17 sequence types (ITS2CA01 ~ ITS2CA17), with the maximum sequence divergence of 2.013% (9 bp) were obtained from ITS2, indicating substantially larger sequence divergence in mitochondrial gene sequence. Phylogenetically, the mitochondrial DNA has shown several haplotypes formed independent groups with substantially high node support (≥ 90%), whereas no such grouping was evidenced for ITS2, indicating different behaviors of the two molecules. Such difference may reflect a diverse dynamics of the species such as biogeographic history, mating behaviors, and also possibly different mode of inheritance of the two molecules, but requires further scrutinized examination of the dataset. In terms of population genetic perspective, overall no population subdivision was detected from both molecules, except for locality 7 (Eocheong islet) from mitochondrial DNA. As more scrutinized analysis is performed, further fruitful inference on the geographic contour of the species might be available.
        35.
        1993.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        글루코오즈(GOD) 옥시다제가 고정화된 PVA/키토산 플렌드막과 다공성 폴리아미드 복합막을 통해 인슐린의 투과거동을 살펴보았다. GOD가 고정화된 막을 통한 투과계수는 10-6~10-7cm3/cm2sec이었다. 복합막의 클루코오즈 농도에 대한 변화는 낮은 글루코오즈 농도에서 높았는데 이는 막으로부터 산소의 고갈 때문이었다. PVA/키토산 및 다공성 폴리아미드막을 통한 인슐린의 투과는 글루코오즈 농도에 따라 500mg%까지 점차 증가하였다.
        4,000원
        36.
        2020.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study analyzes the effect of corporate social responsibility (CSR) activity on investors’ heterogeneous beliefs. The hypothesis of this study is based on the conflicting effects of CSR activities on firm value and earning’s quality. Investors’ heterogeneous beliefs used in the empirical analysis of this study are trading volume, and CSR activity is measured by the KEJI Index (Korea Economic Justice Institute Index). This study performs an empirical analysis using regression analysis including control variables. CSR activities are found to have a positive relationship with trading volume. This is consistent regardless of the low and high accounting information (earning’s quality). It can be interpreted that Korea’s CSR activity acts as an incentive to increase investors’ heterogeneous beliefs about target companies. In other words, it implies that the investor judges CSR activities negatively when evaluating firm value. This study could have a policy implication in that it analyzes how CSR activities affect investors’ decision-making. In other words, this study analyzed CSR activities from the perspective of shareholders. Therefore, this study is expected to provide useful information for policymaking by regulatory agencies. In particular, its contribution is to presents data that CSR activities can be a negative factor in evaluating firm values.
        37.
        2020.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study aims to verify the relationship between overseas activities and performance of Korea’s SMEs during the last financial crisis. Whether overseas activity performance of enterprises differed was determined based on characteristic variables, including the degree of concentration on R&D and marketing. This study also examined how SMEs’ international transactions and their performance differed based on internal variable such as the level of stock holding and firm size. This study developed a model for analyzing the relationship between the level of internationalization and performance of Koran SMEs listed in the KOSDAQ. We used firm-level data, including annual reports and various data sources such as the KISVALUE program. To smooth annual fluctuations in accounting data, we used a three-year average from 2006 to 2009 for each variable in the study. The results showed that proactive overseas activities ultimately had a positive effect on an enterprise’s performance, even though it initially had a negative effect. Therefore, enterprises should focus their capacity on R&D and marketing environment. Although numerous studies have focused on the relationship between overseas activities and performance of enterprises, the present study analyzed whether enterprises should continuously engage in overseas activities and what capacities they should strengthen during a global economic recession.
        38.
        2020.01 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The purpose of this study is to derive various clues for the establishment of marketing strategies for companies that produce and sell high-involvement products for Millennials who are not the subject of current consumption but who will lead future consumption. For this purpose, this study aimed to derive 17 factors of high-involvement product selection attributes through FGI, and its relationship on repurchase intention after make a variable through PCA. A total of 158 valid questionnaires were used, and IPA, independent sample t-test, regression analysis, and hierarchical controlled regression analysis were performed. The results showed that overall, external and internal selection factors had a positive influence on repurchase intentions, and in particular, appealing to internal and external selection factors in order to promote repurchase intention. Meanwhile, the Millennials were found to have no gender difference. Therefore, the company producing and selling high-involvement products suggests that it is necessary to make a priority effort to secure brand awareness, trust in product producers, store trust, and product self-reputation as components of internal selection factors. It was also concluded that more strategic efforts were needed to focus on and appeal to the characteristics of the Millennial itself rather than to consider gender differences.
        39.
        2016.12 서비스 종료(열람 제한)
        The study aimed to evaluate the usability of sterile bag collection (SBC) urinalysis and urine culture for diagnosing urinary tract infections (UTI). Urine culture is key for diagnosing UTI, and transurethral catheterization (TUC) or suprapubic aspiration is recommended for non-toilet-trained children. Although urine testing using SBC is non-invasive and easy, UTI can be diagnosed only if other criteria including clinical symptoms and positive urinalysis results are met. This study included 228 infants who were hospitalized for unexplained fever from October 2015 to June 2016. TUC culture, SBC urinalysis, and urine culture were performed for all patients. UTI was diagnosed when the TUC culture results met the criterion of ≥104 colony-forming units (CFU)/mL. When UTI diagnosis was made based on SBC urine colony counts ≥105 CFU/mL, the false-positive and false-negative rates were 6.3% and 70.0%, respectively. When the criterion was set as ≥104 CFU/mL, they were 23.7% and 30.0%, respectively. When both the criteria of ≥105 CFU/mL and positive urinalysis results were met, the false-positive rate was 2.4%, and the false-negative rate was 80%. Our results suggest that diagnosing UTI using SBC urinalysis and urine culture is not useful in infants with unexplained fever.
        1 2 3