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        검색결과 393

        81.
        2017.10 구독 인증기관·개인회원 무료
        The small brown planthopper (SBPH), Laodelphax striatellus, is one of the most serious pest insects of rice plants.Buprofezin has been used to control SBPH for more than a decade, however, the occurrence of buprofezin resistant SBPHwas reported recently. To develop an alternative pest control an alternative pest control strategy, RNA-seq of buprofezin-treatedSBPH was performed to screen the insecticidal target genes for RNA interference (RNAi). Six genes were selected fordsRNA synthesis, and applied to SBPH to assess the insecticidal efficacy. Two and three of those dsRNAs showed moderatedand substantial insecticidal activity up to 60% of mortality in one week, respectively. These results demonstrated the potentialof gene screening strategy for the development of RNAi-based pest management program.
        82.
        2017.10 구독 인증기관·개인회원 무료
        Widespread use of chemical insecticides has resulted in development of insect resistance and natural products withbiological activities could become an attractive alternative to control insect pests. In order to find more effective insecticidesfor controlling mosquito, various mosquitocidal compounds are studied. Recently, juvenile hormone antagonists (JHANs)are known to be to safe and effective insecticides for control mosquito. In order to identify novel insecticidal compoundswith JHAN activity, several chalcones were surveyed on their JHAN activities and larvicidal activities against Aedes albopictuslarvae. Among them, 2’-hydroxychalcone and cardamonin showed high level of JHAN and mosquito larvicidal activities.These results suggested that chalcones with JHAN activity could be useful for control of mosquito larvae.
        83.
        2017.10 구독 인증기관·개인회원 무료
        Actinobacteria have been known to produce variety of bioactive metabolites that include antibiotics and plant growthfactor. Also, Insecticidal compounds such as avermectin and tetranectin have been reported from actinobacteria. In thisstudy, to identify novel insect growth regulator (IGR)-based insecticidal compounds, 1,283 actinobacteria isolates weretested for their juvenile hormone antagonist (JHAN) activity using the yeast-two hybrid β-galactosidase assay. Amongthem, 25 isolates showed high level of JHAN activity and insecticidal activity against 3rd larvae of diamondback moth,Plutella xylostella. These results suggested that actinobacteria could be unparalleled source of novel IGR-based compounds.
        84.
        2017.10 구독 인증기관·개인회원 무료
        Streptomyces species have been studied to find potent pest control agents as an alternatives to chemical insecticides.Previously, one of the ethyl acetate extract of Streptomyces isolates cultured on unpolished rice medium showed highlevel of juvenile hormone antagonist and larvicidal activities against pest insects including Aedes albopictus, Plutella xylostellaand Laodelphax striatellus. It has been known that the biosynthesis of secondary metabolites of Streptomyces could beinfluenced by a variety environments such as nutritional composition and growth conditions. In this study, to optimizeculture conditions for stable production of insecticidal compounds from this isolate, binding assay and bioassay-guidedmonitoring were conducted using various culture conditions.
        85.
        2017.10 구독 인증기관·개인회원 무료
        Recently, it has been reported that plants produce variety of phytochemicals against insect pests as a part of their defencemechanism. In this study, to identify novel compounds that disrupt juvenile hormone (JH) receptor complex, plant essentialoil compounds were tested using in vitro yeast two-hybrid system transformed with the Aedes aegypti JH receptor complex.Among the plant essential oil compounds, farnesol interfered with pyriproxyfen-mediated binding of A. aegypti Met-FISC.In contrast, farnesyl acetate induced the binding of A. aegypti Met-FISC. Also, both compounds caused retardation ofovarian development and change of transcription level in female A. albopictus. These results could provide insights onthe plant-insect coevolution and may be useful for the development of insect specific and safe pesticides.
        86.
        2017.10 구독 인증기관·개인회원 무료
        RNA interference (RNAi) has been considered as an alternative strategy to control agricultural pests whereby double-strandedRNA triggers a potent and specific inhibition of its homologous mRNA. Since small double-stranded RNAs are requiredfor various RNAi applications, there is a need for cost-effective methods for producing large quantities of high-qualitydsRNA. Bacillus thuringiensis produces much insecticidal proteins with expression of their encoding genes being drivenby sporulation-dependent promoters. To develop dsRNA mass-production platform utilizing Bt, the pHT1K-EGFP plasmidvector which has cyt1Aa sporulation-dependent promoter was constructed. The transcriptional level of target gene (EGFP)is higher 113 times than Bt reference gene (ssPE). It was applied to protect honeybee from Sacbrood virus, so targetgene was replaced to SBV-vp1. By ingestion of Bt-derived dsRNA to honeybee shows positive effect on SBV suppression.
        87.
        2017.10 구독 인증기관·개인회원 무료
        The purpose of this study is to improve practical skill evaluation method of mushroom - trained certified technician's practical skill evaluation which is one of national qualification tests based on national incompetency standards. One of the current National Competency Standards (NCS), mushroom - trained certified technician uses NCS based practical assessment method. In order to improve the current practical evaluation method, we try to improve practical evaluation method based on field customized problem solving ability and improve the practical evaluation method, various evaluation methods should be constructed. On the purpose of identify the diversity and problems of the evaluation method, the experts of the group consultation, the mushroom-related research institute and the related industry collaborated to identify the problems of the actual mushroom - trained certified technician practicum test, This study on the evaluation improvement method was carried out. In this study, the contents of practical test of the current mushroom traits were analyzed and the trends of the latest mushroom industry were widely reflected.
        88.
        2017.10 구독 인증기관·개인회원 무료
        This study is investigated the growth characteristics(number of available stipe, pileus diameter, pileus thickness, stipe length, stipe thickness, object weight, comparison yield ability of 1 cycle) and storage characteristics of ‘Sanjo 701’ (S7) cultivars according to relative humidity. The S7 growth characteristics were investigated by quantifying the growth and the characteristics according to the relative humidity, The storage stability was investigated every 5 days and freshness was measured by ‘Minamide Method’. S7 pileus diameter is The higher the relative humidity was confirmed becomes larger and the more increased relative humidity also increase the comparison yield ability of 1 cycle. However, pileus diameter or stipe length This could not see the big difference in the three treatment groups, the plieus thickness was no significant difference in the treatment of 80% and 95%. The fresh weight of S7 decreased significantly at 80% and 95% relative humidity after 10 days of storage, but decreased continuity in 65% humiditiry. The elongation percentage of S7 pileus was observe in 95% relative humidity, values of L, a and b (SCI), showed the highest L value in 65% and the a value in 95%. b values were similar in 65%, 80% and 95% treatments. On the ‘Minamide Method’ measure freshness was changed from the 10th day of storage at relative humidity of 95%, but humidity of 65% and 80% treatments, it changed after 15 days of storage. In this study growth characteristics and yield were increased at higher relative humidity, but storage stability was decreased. Therefore, it is deemed necessary to change the relative humidity to produce high quality mushrooms.
        90.
        2017.04 구독 인증기관·개인회원 무료
        The Small hive beetle, Aethina tumida (Murray, A. 1867) (commonly abbreviated to SHB), is one of notifiable pest in the world. SHB were confirmed in the southeastern United States in 1998 in a apiary in Florida. The SHB also was found in Korea in 2016. The SHB larvae have relatively large heads and numerous protuberances covering their bodies. Upon full maturation, larvae have reached a length of 10 mm. Adult females are length and width of ± 5.5 mm and ± 3.4 mm. Naturally occurring small hive beetles can vary greatly in size, possibly depending on diet, climate, and other environmental factors. Additionally, we were analyzed the mitochondrial cytochrome oxidase I (COI) gene of the SHBs. The sequence of the COI gene of SHB was identical to that of SHBs in Korea, but different by fourteen positions from Italy.
        91.
        2017.04 구독 인증기관·개인회원 무료
        The technique of artificial insemination is the possible one that can surely control mating of the selected drones with the virgin queen. This technique was first time applied with A. cerana in Korean. The average amount of semen can collected from one Korean A. cerana drone was 0.09 μl and 0.1 μl of Vietnamese one, whereas the A. mellifera was more than 6 times (0.58 μl semen per A mellifera drone). Obtaining 1 μL of semen have to collect from 11.94 drones that successful semen ejection. Queens artificially inseminated with 4 μl of semen (once insemination) or 8 μl of semen twice (each insemination with 4 μl of semen) started laying egg later than naturally mated queens 5.3 and 2.5 days, respectively. The onsets of oviposition of artificially inseminated queens were 12.5 to 15.3 days.
        92.
        2017.04 구독 인증기관·개인회원 무료
        Due to their environmental and economical consequences, invasive species have become a major concern worldwide. Among them, the yellow-legged hornet, Vespa velutina, is a keen hunter of domestic honeybees. They use olfactory cues from the prey to assess food information. In this study, we investigated the attraction behavior of V. velutina to honeybee pheromone under outdoor conditions. Nine honeybee pheromones were tested and compared in order to find the best attractant. When testing specific compounds, the honeybee queen pheromone, homovanillyl alcohol, proved highly attractive.
        93.
        2017.04 구독 인증기관·개인회원 무료
        Secondary metabolites isolated from Actinomycete have been studied to find potent pest control agents as their insecticidal and growth inhibitory activities. In order to investigate novel insecticidal compounds, second metabolites from 363 Actinomycete isolates were evaluated for their insect growth regulatory activities. Among them, ethyl acetate extracts from ten Streptomyces spp. showed high level of Juvenile hormone antagonist activity. In addition, their insecticidal activities were tested against larvae of Aedes albopictus, Plutella xylostella and Laodelphax striatellus. These results suggested that secondary metabolites from Streptomyces spp. could be used for development of novel IGR-based insecticides.
        94.
        2017.04 구독 인증기관·개인회원 무료
        Plant essential oils have been reported to show repellent, insecticidal and growth-reducing effect on many insect herbivores. Recently, it has been reported that plants synthesize secondary metabolites regulating insect juvenile hormone (JH) receptor complex as a part of their defense mechanisms. We tested 180 plant essential oil compounds using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system. Among them, we identified 17 compounds that showing high JH agonist (JHA) or antagonist (JHAN) activities. They were grouped into 4 groups by their structural similarity and their insecticidal activity was tested against larvae of Aedes albopictus, Plutella xylostella, Plodia interpunctella and Laodelphax striatellus. These results could provide insights on the plant-insect coevolution and may be useful for the development of insect specific and safe pesticides.
        95.
        2017.04 구독 인증기관·개인회원 무료
        RNA interference (RNAi) is an universal gene-knockdown mechanism in eukaryotic organisms including insects. RNAi has been considered as an alternative strategy to control agricultural pests whereby double-stranded RNA triggers a potent and specific inhibition of its homologous mRNA. Bacillus thuringiensis (Bt) is a spore-forming bacterium that produces a copious amount of crystal proteins δ-endotoxins under the control of sporulation-dependent promoter. In order to develop dsRNA mass-production platform utilizing recombinant Bt, the pHT1K-EGFP which expresses dsRNA against EGFP under the control of Cyt1-Aa sporulation-dependent promoter was constructed and the expression level of transgene (EGFP) was confirmed by qPCR analysis. These results suggested that Bt’s potential of becoming a new platform in dsRNA production.
        96.
        2017.04 구독 인증기관·개인회원 무료
        Insect growth regulators (IGRs) are insecticides that disrupt the normal development of target insects by inducing symptoms such as premature molting or supernumerary larval stages. Juvenile hormone (JH)-based IGRs are of particular interest because they simulate or interfere with the formation of juvenile hormone receptor complex. Insect larvae generally have been poorly susceptible to JH agonists (JHAs) because endogenous JH titer is already high in the larval stage. In contrast, JH antagonists (JHANs) might be more effective for control of target pests in larval stages through interference in the status quo action of JHs. In this study, we tested 2,354 chemical compounds using the yeast-two hybrid system to identify JHANs. Among them, K265674 sample was selected and its insecticidal activity was evaluated against Aedes albopictus larvae. These results may be useful for development of novel IGR insecticide.
        97.
        2017.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. They produce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenic fungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanisms of host insect. In this study, acetone extract of the Lecanicillium spp. cultured on unpolished rice medium showed juvenile hormone antagonist (JHAN) activity in the yeast-two hybrid β-galactosidase assay and high insecticidal activity against Aedes albopictus and Plutella xylostella. In addition, to compare bioactivities of secondary metabolites from solid and liquid culture, the Lecaniciilium spp. strain cultured on unpolished rice medium or PDB medium were serially extracted with acetone and ethyl acetate respectively. Both extracts showed JHAN activity and high insecticidal activity against A.albopictus. Theses results suggested that secondary metabolites of entomopathogenic fungi could be useful for development of novel IGR insecticides.
        98.
        2017.04 구독 인증기관·개인회원 무료
        Rice stripe virus (RSV) is one of the serious plant pathogenic viruses for rice transmitted by small brown planthopper (SBPH), Laodalphax striatellus. RNA interference (RNAi) was recently suggested as a promising strategy for controlling insect pests, including those that serve as important vectors for plant pathogens. To disturb transmission of the RSV in SBPH using RNAi pathway, we chose nine genes highly expressed in RSV-viruliferous SBPH by transcriptome sequencing. These SBPH-derived dsRNAs were applied to the insects indirectly through xylem of rice leaves by irrigation. qPCR result demonstrated that five out of nine SBPH-derived dsRNAs successfully reduced the replication of RSV in viruliferous SBPH in dose-dependent manner, suggesting that these five dsRNAs could suppress replication of RSV and provide a new tool for RSV control strategy.
        100.
        2016.11 구독 인증기관·개인회원 무료
        Most known species in the Strophariaceae are decomposers and grow on various kind of organic matter. Approximately 18 genera and 1,316 species in the Strophariaceae have been reported worldwide. Through an ongoing survey of indigenous fungi in Korea, 29 specimens belonging to the Strophariaceae were collected from 2012 to 2016. These specimens were identified based on morphological characteristics and molecular analysis of internal transcribed spacer sequences. Fifteen taxa were confirmed, with eight species matching those previously recorded. Seven species in five genera were shown to be new records in Korea: Galerina marginata, Gymnopilus crociphyllus, Gymnopilus picreus, Hebeloma birrus, Hebeloma cavipes, Pholiota multicingulata, and Psilocybe thaizapoteca. In this study, we provide detailed morphological descriptions of these species and investigate their evolutionary relationships by constructing phylogenetic trees.
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