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        검색결과 281

        101.
        2015.11 구독 인증기관·개인회원 무료
        Medical mushroom, Phellinus linteus and Phellinus baumii called as “Sanghwang” have cultivated in Korea. PL has been studied extensively for its extraordinary capacity of suppressing cancer or enhancing body immunity. The mycelial materials of PL have mainly been used as research samples worldwide because fruiting bodies was difficult to be artificially cultivated. Alternatively, P. baumii (variety, ‘Jangsu’) have been cultivated in Korea. However, fruiting body morphology of P. baumii is clearly different to that of PL. Generally, Phellinus spp. including P. linteus slowly grow on artificial medium such as Potato Dextrose Agar (PDA). In contrast, P. baumii strains were rapidly grown on the artificial media when compared to other Phellinus spp. and thus it was considerable that its mycelial growing ability can be acted as a factor for producing fruiting bodies. This study aimed to find Phellinus isolates having high mycelial growth rate. Five Phellinus isolates that show rapid growth rate on YGM medium were selected from 36 Phellinus isolates collected in Korea. They were identified on nucleotide sequences of rDNA-ITS region. Phellinus linteus strain and Phellinus spp. showing mycelial growth rate comparing to P. baumii were characterized on cultural and bioactive characteristics (antioxidant activity and immune activation).
        103.
        2015.10 구독 인증기관·개인회원 무료
        Bean bug, Riptortus pedestris is an agriculturally serious pest in north eastern Asian countries, damaging to several legumes and fruit trees. Chemical pesticides have been largely used to control the pest but it encounters insecticide-resistance and environmental toxicity issues. Alternatively different mode of action and environmentally sound pest management system can be found in entomopathogenic fungal insecticides. Herein we developed a platform to optimize the fungal production to express their maximum virulence against bean bug, by focusing on solid culture system for thermotolerance, formulation to select effective surfactants to carry the fungal conidia on the cuticles, and relationship between environmental abiotic factors and fungal mortality. First to produce highly thermotolerance fungal conidia, Beauveria bassiana and Metarhizium anisopliae isolates were cultured on several granular cereal substrates, which could be subjected to formulation process. Among the tested media, four media (millet, non-glutinous italian foxtail millet, glutinous italian foxtail millet, brown rice) were superior to the other grains in the spore production and thermotolerance. Next to efficiently deliver the fungal conidia on the cuticles of bean bug, total of six surfactant (CO-2.5, CO-12, LE-7, PE-61, TED-3 and Siloxane) was used to experiment. CO-12 was superior to the other surfactant in mortality of 100 ppm consistence. This work suggests that solid culture system and formulation and application should be seriously considered to reach an optimal level of mortality by inducing their maximum virulence.
        104.
        2015.10 구독 인증기관·개인회원 무료
        Entomopathogenic fungi are facultative microorganisms, dwelling in soil or infecting host insects, and some of the genera have been used as biological control agents worldwide. Collection of fungal isolates should be a platform for the development of highly effective resources, thus in this work we constructed a fungal library using a mealworm pathogenecity-based fungal collection method and further characterized some isolates with high virulence. A phylogenetic three was generated, and of the isolates 17 isolates’ biological features were characterized, such as morphology, spectrum of virulence, cultural characteristics, thermo-stability of fungi, production of biologically active materials, such as enzymes. This work reports an attractive entomopathogenic fungal library including the information of effective isolates in pest management.
        105.
        2015.10 구독 인증기관·개인회원 무료
        The present issue of insect resistance and environmental toxicity of pesticides is triggering deep discussion about the pest management tactics, in which pest monitoring and control activity are mainly involved. Novel control agents, hopefully overcoming the present issues and problems, should be researched and commercially applied to the farm fields. With the monitoring-based research, additionally we have to focus on the control-based, particularly control agent-based research and application. Entomo- pathogenic fungi can used as one of the possible novel control agents once considerations are given to the control of soil- or water-dwelling pests. In our research group, the entomopathogenic fungal library has been constructed using the mealworm-based isolation system, which showed a variety of opportunities of their use in pest control. Important key production technologies including granular formulation have been developed to increase their industrialization. Some entomopathogenic fungal isolates showed high biological performance in the control of rice weevils, western flower thrips and Japanese bettles in field stands. To elucidate the fungal mode of action, a fungal transformation system using AtMT and gene identification tools were established. Recently a more deep study about the relationship between insect and entomopathogenic fungi is be investigated using RNA seq. We suggest that to make the entomopathogenic fungal products be applied to agricultural farm field, R&D of down-stream process should be seriously considered as the key step.
        106.
        2015.10 구독 인증기관·개인회원 무료
        ocust, Locusta migratoria (Orthoptera: Acrididae) is one of the outbreaking pests worldwide and such big occurrence was recorded in 2014, Korea, however little consideration was given to the management strategy of the pest. Herein we established a indoor locust-rearing system and constructed a locust-pathogenic fungal library to further facilitate the resources to be used as possible biological control agents. A locust colony was provided from the National Institute of Agricultural Science and Technology and reared in corn or barley plants at artificially manipulated rooms. The critical developmental stages, such as oviposition, hatching and mating were successfully proceeded. Entomopathogenic fungal granules were treated to the locust (2 g/rearing box), and in 5~7 days mycosis was observed in the membranous cuticles of head, abdomen and legs. In particular JEF-003 (Metarhizium anisopliae), JEF-186 (M. lepidiotae) and JEF-187 (Clonostachys rogersoniana) showed high virulence against the locust. A population of locust was exposed to the entomopathogenic fungal conidia-incorporated soil to investigate the possibility of the fungal isolation from natural soil, which resulted in the pathogenesis in 7~10 days in laboratory conditions. More than 80% of control efficacy was observed in the greenhouse trial of fungal granular application. This work suggests that locust rearing system was successfully established and entomopathogenic fungi can be used to control the migratory locust.
        107.
        2015.10 구독 인증기관·개인회원 무료
        Bean bug, Riptortus pedestris is an agriculturally serious pest in East Asian countries, reducing the value of crop quality and loss of income in agribusiness. Chemical pesticides have contributed to the management of the pest, but nowadays insect resistance limits the use of chemical pesticides, thus alternatively new pesticides with different mode of actions such as entomopathogenic fungi are considered. Beauveria bassiana and Metarhizium anisopliae JEF isolates were collected, identified and assayed against bean bugs in laboratory conditions. Some isolates showed >80% virulence by spray and contact-exposure methods. Supernatant showed different level of enzyme activity including chitinase, Pr1 protease and lipase. The Agrobacterium tumefaciens-mediated transformation generated random transformants and some mutants had reduced virulence. TAIL-PCR of the random transformants revealed virulence-related genes. This work can be a strong platform for the functional genetics of bean bug-pathogenic B. bassiana.
        108.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A large-scale neutral hydrogen (H i) ring serendipitously found in the Leo I galaxy group is 200 kpc in diameter with MHi ~ 1:67 X 109M⊙, unique in size in the Local Universe. It is still under debate where this Hi ring originated - whether it has formed out of the gas remaining after the formation of a galaxy group (primordial origin) or been stripped during galaxy-galaxy interactions (tidal origin). We are investigating the optical and Hi gas properties of the dwarf galaxies located within the gas ring in order to probe its formation mechanism. In this work, we present the photometric properties of the dwarfs inside the ring using the CFHT MegaCam u*, g', r' and i'-band data. We discuss the origin of the gas ring based on the stellar age and metal abundance of dwarf galaxies contained within it.
        3,000원
        109.
        2015.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbohydrate derivatives of cyanidin, a class of anthocyanin pigments, are major component of red cabbage, which is responsible for the characteristic reddish color. The color of cyanidin derivatives is quite stable against heat, and here we aimed to identify the chemical component of glucoside-derivatives of cyanidin which is responsible for the thermal stability. By comparing the thermal stability of color from unmodified cyanidin and cyanidin-3,5-diglucoside with the color of cyanidin derivatives from red cabbage, we found that the glucoside modification confers the thermal stability. We believe that our finding will contribute to the preparation of heat-resistant anthocyanin pigments for food coloring and other applications.
        4,000원
        111.
        2015.04 구독 인증기관·개인회원 무료
        Entomopathogenic Beauveria bassiana and Metarhizium anisopliae are well-known biological control agents worldwide and have high potential in industrialization. However their thermo-susceptibility limits long-term storage under high temperature conditions and high insecticidal activity after application to target pests. Herein we isolated highly virulent isolates, B. bassiana JEF006 and JEF007 and M. anisopliae JEF003 and JEF004, and produced in three grains, such as sorghum, millet and Italian millet as substrates for solid cultures, followed by thermotolerance assays to compare the potential of the three substrates for thermotolerance. The JEF isolates were exposed to dry and wet heat at 50°C and overall conidia were more stable under dry heat condition rather than wet heat. Of the three grains, Italian millet was superior to the other grains in the production of thermotolerant conidia. Additionally Italian millet did not severely aggregated, which enabled air to penetrate into the substrate well compared to the sorghum and millet. JEF isolates were more thermotolerant when they were kept in oil conditions as carriers of an oil-based formulation. This work suggests that Italian millet can be used as an effective substrate to produce more thermotolerant conidia, thus maintaining viability for long times under unfavorable environment and biological activity against target pests.
        112.
        2015.04 구독 인증기관·개인회원 무료
        Bean bug, Riptortus pedestris is an agriculturally serious pest in East Asian countries, reducing the value of crop quality and loss of income in agribusiness. Chemical pesticides have contributed to the management of the pest, but nowadays insect resistance limits the use of chemical pesticides, thus alternatively new pesticides with different mode of actions such as entomopathogenic fungi are considered. Beauveria bassiana and Metarhizium anisopliae JEF isolates were collected, identified and assayed against bean bugs in laboratory conditions. Some isolates showed >80% virulence by spray and contact-exposure methods. The isolates produced high levels of pathogenesis-related enzymes, such as chitinase, Pr1 protease and lipase. The Agrobacterium tumefaciens-mediated transformation generated random transformants and some mutants had reduced virulence against bean bugs, which provided some materials to figure out pathogenicity-related genes in the fungi. Now characterization of flanking region of the integrated fragment is underway and this work may reveal some important genes in the pathogenesis. This work can be a strong platform for the functional genetics of bean bug-pathogenic B. bassiana.
        113.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of seed soaking treatment with the solutions of plant growth regulators IAA, GA3 and BAP on seed germination and shoot and bulb growth of Allium victorialis var. platyphyllum (Korean wild garlic) were determined. A significant variation in the seed germination rate was recorded at all treatments for various soaking periods. Maximum seed germination was obtained when seeds were soaked in IAA or GA3 solution at 200 mg L-1. The MAP treated seeds started to germinate after 3 months. Among treatments, IAA was found to be most effective in improving seed germination, but further seedling growth was not correlated to the soaking time. Seed soaking in IAA or GA3 solution enhanced further growth of seedlings compared with water control treatment. Shoot and bulb growth was highest in GA3 treatments.
        4,300원
        114.
        2014.10 구독 인증기관·개인회원 무료
        We investigated the insect community along altitudinal gradient to gather basic data for distributional monitoring of insect species in the forest ecosystem. The investigation area was Seon-gaksan (Mt.) in Jinan-gun, Jeollabuk-do province, where the bucket-light trap and pit-fall trap for quantification were installed in Quercus vegetation at altitude of 300m, 600m and 900m. The field collecting was performed on May, July and September 2013 respectively. ANOVA analysis was conducted to analyze the significance between insect species along altitude using the collected insect community data. Analysis of variance (ANOVA) results showed statistically significant differences among ground-beetles and ants abundance with altitude as a response variable. Although we expected a distinct cluster with the difference of altitude at each study site, nonmetric multidimensional scaling (NMS) showed distinct clusters with the moth, ground-beetles, and ant assemblage at altitudinal increase and sampling month. In the result, a total of 309 species in 18 families of nocturnal moths were collected by bucket-light trap. The insects collected in pit-fall trap were ground-beetles with 196 individuals of 26 species and ants with 11,276 individuals of 14 species respectively.
        115.
        2014.06 구독 인증기관 무료, 개인회원 유료
        Xylitol is a five-carbon sugar alcohol that inhibits the growth of oral streptococci, including Streptococcus mutans. In this study, we tested xylitol sensitivity among the oral streptococci. We also compared nucleotide homology of putative fructose phosphotransferase system (PTS) and xylitol sensitivity, since xylitol is transported via the fructose PTS. Among the tested Streptococci, S. pneumonia showed the highest resistance to xylitol while S. gordonii and S. sanguinis showed the most sensitive growth inhibition. These streptococci could be grouped according to their xylitol sensitivity. S. mutans and S. salivarius showed similar bacterial growth inhibition by xylitol. S. mitis, S. oralis, S. pneumonia, S. intermedius and S. anginosus showed relatively low sensitivity to xylitol. When the genetic homologies of five fructose PTSs were compared among the tested streptococci, closely related streptococci showed similar sensitivity to xylitol. Taken together, fructose PTSs may mediate the sensitivity to xylitol in oral streptococci.
        4,000원
        117.
        2014.04 구독 인증기관·개인회원 무료
        Urbanization is one of the leading causes of habitat loss, habitat degradation, and fragmentation. Urban development negatively affects biodiversity. This study aimed to clarify the change of butterfly communities on effect of urbanization in urban green areas. Butterfly survey was conducted using the line transect methods from April to October in 2012. A total of 59 species and 1,465 individuals of butterflies were observed in four urban green areas: Namsan Park (NS), Ewha Womans University (EW), Bukseoul Dream Forest (BD), and Hongneung Forest (HF), and natural forest: Gwangneung Forest (GF). The category of land use around study site was determined based on GIS data. Species richness and abundance of niche breadth and habitat type in urban green areas differed significantly from those in GF. Estimated species richness and species diversity (H’) in four urban green areas were significantly lower than those in GF. Species richness and abundance of forest interior species and specialist were positively correlated with paddy, field, and forest, whereas those of forest interior species and specialist were negatively correlated with urban area and road. Butterfly communities in four urban green area differed from that in GF. The result suggests that the decrease of paddy, field, and forest associated with increase of urban area and road negatively influences species composition and changes butterfly communities.
        118.
        2013.10 구독 인증기관·개인회원 무료
        Insect cuticular melanization is regulated by the prophenoloxidase (proPO)- activating system, which is also involved in the innate immune reaction. Here, we demonstrate how the differentiation of the proPO-activating system is regulated toward a cuticular melanization or innate immunity function in silkworm (Bombyx mori) pupae. Our results indicate that the differential and spatial regulation of key components, such as the proPO-activating factor, tyrosine hydroxylase, and porPOs, primes the proPO-activating system for either cuticular melanization or innate immunity. This dual strategy for cuticular melanization in development and innate immunity upon infection demonstrates a two-pronged defense mechanism that is mediated by the priming of the proPO system.
        119.
        2013.10 구독 인증기관·개인회원 무료
        Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03 nM) and proteinase K (Ki 91.53 nM), but not against α-chymotrypsin or typsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, B. thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor.
        120.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The high quality contact between graphene and the metal electrode is a crucial factor in achieving the high performance of graphene transistors. However, there is not sufficient research about contact resistance reduction methods to improve the junction of metal-graphene. In this paper, we propose a new method to decrease the contact resistance between graphene and metal using directly grown graphene over a metal surface. The study found that the grown graphene over copper, as an intermediate layer between the copper and the transferred graphene, reduces contact resistance, and that the adhesion strength between graphene and metal becomes stronger. The results confirmed the contact resistance of the metal-graphene of the proposed structure is nearly half that of the conventional contact structure.
        3,000원