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        검색결과 22

        3.
        2016.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungus is a useful control agent to sucking type insect such as whitefly and aphid. The fungi are influenced by some environmental factors such as relative humidity, temperature and UV and cause slow and fluctuation in pest control efficacy. Especially, UV kills conidia or spores of entomopathogenic fungi and a mycopesticide using fungi has short control period in field. UV intensity changes from season to season. Survival rate of entomopathognic fungi treated may differ from seasons and will show different control efficacy. Therefore, we conducted a study to estimate the persistence of an Isaria javanica isolate, which was already reported as sweet potato whitefly control agent, in potted greenhouse soil planted different crops. The number of survival spore decreased gradually and differ from seasons.
        4.
        2016.04 구독 인증기관·개인회원 무료
        Insect pests have been a serious problem over many years and remain a major threat for food production. Although chemical pesticides are major pest control strategies, use of microorganisms such as entomopathogenic bacteria, fungi, viruses and nematodes have continuously increase last few decades to minimize the use of agrichemicals. According to BBC research, the global biocontrol market was about $2.1 billion in 2011, and this is expected to rise $3 ~ 4 billion by 2017. Over 50 entomopathogens are commercially produced and used augmentatively as microbial pesticides. About 175 biopesticide active ingredients and 700 products have been registered worldwide. Bacillus thuringiensis (Bt), Beauveria bassiana, Metarhizium spp., nuclear polyhedrosis virus and Steinernema spp. are the most popular control agents used in plant protection. Among the microbial control agents Bt products have more than 50% of market share. In Korea, only 13 environmentally-friendly crop protectants were registered for insect pest control in 2015. Market share is very low and has grown slowly. We will discuss how we can expand the market with our techniques.
        5.
        2014.04 구독 인증기관·개인회원 무료
        The Riptortus-Burkholderia symbiosis is a newly emerging insect-bacterium symbiotic system. This symbiosis system has a good merit as an experimental model system to produce the non-symbiotic (apo) and symbiotic (sym) host insect. In recent reported papers, the symbionts play important biological roles for the host insects. Meanwhile, juvenile hormone (JH) is one of major hormone synthesized corpora allata(CA) to control many physiology of insect. However, the study for cross-talk mechanism between symbionts and host hormones to control important physiological phenomenon of insects is almost none. In this study, we found that Riptortus speed up adult emerging and increase egg laying on presence of symbiont Burkholderia. Also we found that hexamerin proteins, which were controlled the expression by JH, were accumulated in sym-Riptortus hemolymph compare with apo-Riptortus. According as combined results, we hypothesized that the gut symbiont Burkholderia can control JH titer to conclude out beneficial effects such as development and reproduction of R. pedestris. To verify this hypothesis, we examined measurement of JH titer, expression of hexamerins as JH response genes and RNAi for hexamerin protein during whole Riptortus life on presence or absence of symbiont Burkholderia. All results demonstrated that gut symbiont controlled JH titer of Riptortus. Controlled JH amount by symbiont Burkholderia in host midgut regulated hexamerin protein expression for speeding up adult emerging and increasing egg production.
        6.
        2014.04 구독 인증기관·개인회원 무료
        Various insect pests infest crops including vegetables and ornamentals during crop production. Chemical pesticides have generally used until recently to control pests. Many pests are very difficult to control using organic pesticides because of the development of insecticide resistance and their rapid population increase. Entomopathogens are the promising alternative control methods. Entomopathogenic fungi are good candidates to control sucking insects such as aphid, whitefly and mite because the fungi can infect without ingestion. Conidia or blastospores of fungal entomopathogens are sprayed onto target plant and/or insect, adhered on insect surfaces, and penetrated into hemocoel through insect cuticle. Then the fungus utilize insect nutrients and kill the host insect. During this process, fungus was influenced by environmental conditions such as temperature, relative humidity and UV light. These are causing slow mortality and preventing wider application and use of mycopescitide using entomopathogenic fungi. In addition, control efficacy with fungal entomopathogen differed fungal isolate and host insect. Therefore, we need to study selection of high virulence isolate, mass production, formulation and application techniques to develop mycopesticide.
        7.
        2013.10 구독 인증기관·개인회원 무료
        Use of conidia or spores of entomopathogenic fungi are influenced by environmental conditions such as temperature and relative humidity and caused slow and fluctuation of mortality. In addition, although the fungi have the advantage of a restricted host range, this specificity is one of the limiting factors for their use. These factors are preventing wider application and use of these biocontrol agents. To mitigate such problems we selected an Beauveria bassiana Bb08 which kill green peach aphid with its liquid culture filtrate. In this study we conducted bioassay with the fungal culture filtrate and culture fluid to greenhouse pests such as cotton aphid, whitefly and thrips. Culture fluid showed high mortality against green peach aphid, as well as cotton aphid, sweet potato whitefly, and western flower thrips. However, control effect of culture filtrate varied with pests. Culture filtrate showed high mortality to cotton aphid. Mortality of western flower thrips with culture filtrate was slower than culture fluid including spores and sweet potato whitefly was much lower. These results indicated that the culture fluid of Beauveria bassiana Bb08 has potential to simultaneously control various greenhouse pests.
        8.
        2013.04 구독 인증기관·개인회원 무료
        Sweetpotato whitefly (Bemisia tabaci), especially Q biotype, has been recognized one of the most destructive insect pests worldwide because of increased resistance to some insecticide groups requiring alternative strategies for its control. We studied the conidia production of entomopathogenic fungus Isaria javanica Pf04, which had been reported high virulence isolate against Q biotype of B. tabaci, using grain. Brown rice was most suitable for conidia mass production of the isolate of I. javanica. Conidia was produced high at 25 ~ 27.5℃. The isolate produced more spores when conidia suspension directly inoculated onto media than two-phase fermentation. When concentration of inoculum was high spore production was high, but increasing rate of conidia production was highest at low inoculum concentration (1×105 conidia/ml) as 6,700 times increase compared with 20 times increase at high inoculum concentration (1×108 conidia/ml). These results indicated that the isolate can produce more conidia with cheap agricultural product and can develop as a microbial pesticide to control sweetpotato whitefly.
        9.
        2012.12 구독 인증기관 무료, 개인회원 유료
        As the demand for large-scale analysis of gene expres- sion using DNA arrays increases, the importance of the surface characterization of DNA arrays has emerged. We com- pared the efficiency of molecular biological applications on solid-phases with different surface polarities to identify the most optimal conditions. We employed thiol-gold reactions for DNA immobilization on solid surfaces. The surface polarity was controlled by creating a self-assembled monolayer (SAM) of mercaptohexanol or hepthanethiol, which create hydrop- hilic or hydrophobic surface properties, respectively. A hyd- rophilic environment was found to be much more favorable to solid-phase molecular biological manipulations. A SAM of mercaptoethanol had the highest affinity to DNA mole- cules in our experimetns and it showed greater efficiency in terms of DNA hybridization and polymerization. The opti- mal DNA concentration for immobilization was found to be 0.5 mM. The optimal reaction time for both thiolated DNA and matrix molecules was 10 min and for the polymerase reaction time was 150 min. Under these optimized condi- tions, molecular biology techniques including DNA hybri- dization, ligation, polymerization, PCR and multiplex PCR were shown to be feasible in solid-state conditions. We de-monstrated from our present analysis the importance of surface polarity in solid-phase molecular biological appli- cations. A hydrophilic SAM generated a far more favorable envi- ronment than hydrophobic SAM for solid‐state molecular techniques. Our findings suggest that the conditions and met- hods identified here could be used for DNA‐DNA hybri- dization applications such as DNA chips and for the further development of solid-phase genetic engineering applicatio- ns that involve DNA-enzyme interactions.
        4,000원
        10.
        2011.09 구독 인증기관 무료, 개인회원 유료
        In the present study, total methanol extracts prepared from Alpinia katsumadai showed significant protective effects against the oxidative stress induced by hydrogen peroxide, UV-C or γ-ray irradiation. These protective effects were substantially increased by treatment with 20~100 μg/ml of the extract. The A. katsumadai total methanol preparation was further fractionated into n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these five fractions, the ethylacetate and butanol fractions of A. katsumadai showed the strongest protective effects against oxidative stress induced by UV-C and γ-ray irradiation. These fractions also showed high DPPH radical scavenging and lipid peroxidation inhibitory activities. In addition, both fractions displayed cell proliferation activation effects, as evidenced by significant increases in colony formation. Our current data thus suggest that the mechanisms underlying the protective effects of A. katsumadai against oxidative damage may include radical scavenging, protection against cell membrane damage and stimulation of cell proliferation.
        4,000원
        13.
        2008.12 구독 인증기관 무료, 개인회원 유료
        The present study reports the protective properties of a total methanol extract of B. platyphylla var. japonica against ultraviolet (UV)-C irradiation. Pretreatment of Chinese hamster fibroblast (V79-4) cells with a total methanol extract significantly increased cell survival following 300J/m² of UV-C irradiation. The total methanol extract was further fractionated into 5 fractions: n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these fractions, B. platyphylla var. japonica ethylacetate, butanol and water fractions showed significant protective effects against the cellular damage induced by UV-C irradiation. In order to elucidate the mechanism underlying this protective effect, DPPH (Editor note: abbreviations should be spelled out at first use.) radical scavenging and lipid peroxidation inhibitory activity were measured. Significant radical scavenging and lipid peroxidation inhibitory activities were observed for the ethylacetate fraction. In summary, the present data demonstrate that an extract of B. platyphylla var. japonica has a significant protective effect against UV-C irradiation. The underlying mechanism of this protective effect may involve radical scavenging and inhibition of lipid peroxidation by the B. platyphylla var. japonica extract.
        4,000원
        15.
        2018.10 서비스 종료(열람 제한)
        Background : Ixeris strigosa is a herb which has used leaves and roots in Korea. Recently, the cultivation area and food imports have been increased because it has been used as an functional crops for anti-obesity. However its cultivation method has not been developed and it is difficult to produce with good quality. Therefore, this experiment was carried out to determine the optimum seedroot size, plant number per hill, planting time, planting density, planting method and mulching materials for improving the cultivation method suitable for domestic environment. Methods and Results : In order to identify the proper cultivation method, I. strigosa was collected in Dangjin, Chungnam in 2016 and the yield and crop characteristics were investigated at the end of October. The seedroots were cultivated by size such as large (length 30 ㎜, thickness more than 1 ㎜), medium (30 ㎜, 1 ㎜ - 1.5 ㎜) and small (30 ㎜, less than 1 ㎜). As a result, the production of the medium-sized seedroot was highest at 950 ㎏/10a. Based on these results, medium-sized seedroots passed winter in previous year were used when plant number per hill, planting time, planting density, planting method and mulching materials were investigated. At plant number per hill, 3 seeds/hill was the highest at 836 ㎏/10a among 1, 3 and 5 seeds/hill. When the seedroots were planted at intervals of one month from mid April to mid August, the yield was the highest at 1,647 ㎏/10a at the middle of May. When the planting densities were 10 × 10, 20 × 10, 20 × 15 and 20 × 20 ㎝, 10 × 10 and 20 × 10 ㎝ had highest production. And two methods for planting have been used, one was to plant at right angles and the other to lay down. As a result, the latter yield was 612 ㎏/10a. Finally, when comparing non woven fabrics, color combination polyethylene film, black polyethylene film and no treatment among the mulching materials, black polyethylene film made the highest yield at 1,044 ㎏/10a. Conclusion : For improving the cultivation of I. strigosa, this study determined the optimum seed size, plant number per hill, planting time, planting density, planting method and mulching materials. In conclusion, the production was the best when the plant was laid down on a black polyethylene film at intervals of 20 × 10 ㎝ at the middle of May, using 3 medium-sized seeds per hill. These results are expected to contribute to the productivity and income farmers of I. strigosa.
        16.
        2014.03 서비스 종료(열람 제한)
        Pulmonary tuberculosis is an important public health problem. Early diagnosis and treatment is necessary for successful patient outcomes. However, diagnosis of pulmonary tuberculosis is difficult in cases with an unusual presentation and often requires a lung biopsy. The tuberculosis polymerase chain reaction results in tissue sample have potential for early diagnosis and treatment initiation for pulmonary tuberculosis. The relatively low sensitivity limit the use of this test in the detection of the pulmonary tuberculosis.
        17.
        2013.03 서비스 종료(열람 제한)
        The association between human parvovirus B19 and aplastic crisis in patients with hemolytic anemia, such as sickle-cell anemia and hereditary spherocytosis, has been well described. However, most cases of parvovirus induced-aplastic crisis in patients with hereditary spherocytosis have been reported in children or adolescents. We report on a 31-year-old female with pancytopenia who was diagnosed with aplastic crisis caused by parvovirus B19 infection in hereditary spherocytosis. It should be kept in mind that hereditary spherocytosis may initially present with aplastic crisis induced by parvovirus B19 infection in adults
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