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        검색결과 120

        41.
        2016.10 구독 인증기관·개인회원 무료
        Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have been shown to synthesize IGRs that affect the insect juvenile hormone (JH) as a part of their defense mechanisms. We identified several JH agonists (JHAs) and antagonists (JHANs) from plant essential oil compounds using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system. They showed high mosquitocidal activities with relatively low LC50 values and caused retardation of ovarian development in female mosquitoes. While the JHAs increased the expression of JH-induced gene, the JHANs caused reduction in the expression of the same gene. The compounds identified in this study could provide insights on the plant-insect interactions and may be useful for the development of novel IGR insecticides.
        42.
        2016.10 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, Beauveria spp. and Lecanicillium spp. strains cultured on unpolished rice medium were extracted with acetone. Both extracts showed juvenile hormone antagonist (JHAN) activities in the yeast-two hybrid β-galactosidase assay. In addition, they showed high insecticidal activities against Aedes albopictus, Plutella xylostella, and Ostrinia furnacalis. These results suggested that secondary metabolites of entomopathogenic fungi could be useful for development of novel IGR insecticides.
        43.
        2016.10 구독 인증기관·개인회원 무료
        Streptomyces is the largest genus of Actinobacteria that forms fungus-like branched networks of hyphae. Streptomyces has been clinically important because they produce various secondary metabolites with antibacterial, antifungal, and nematocidal activities. In order to explore novel insecticidal compounds, extracts from 363 strains of Actinobacteria were screened for their juvenoid and anti-juvenoid activities using yeast-two hybrid system. Among them, extract of Streptomyces spp. showed high anti-juvenoid activity. This extract also showed high level of insecticidal activities against larvae of Aedes albopictus, Laodelphax striatellus, and Ostrinia furnacalis. These results suggested that the secondary metabolites of Streptomyces could be natural sources of novel insecticidal compounds.
        44.
        2016.10 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. IGRs are categorized into three types based on their mode of action. One of the them is classified as juvenile hormone agonists (JHAs). In recent studies, we identified juvenile hormone antagonists (JHANs) from plant extracts. In order to identify a novel juvenile hormone agonists and antagonists, we tested 2,354 chemical compounds using the yeast-two hybrid system. Among them, 2 JHAs and 4 JHANs were selected and their insecticidal activities were evaluated against Aedes albopictus larvae. These results may be useful for development of novel IGR insecticides.
        46.
        2015.10 구독 인증기관·개인회원 무료
        Insect growth regulators (IGRs) are compounds that induce developmental anomalies such as premature molting or supernumerary larval stages. IGRs can be divided into 3 groups based on their mode of action, one of which is known as the juvenile hormone agonists (JHAs). Previously, we have developed a novel screening method which can identify juvenile hormone antagonists (JHANs) using a yeast-two hybrid system incorporating Aedes aegypti juvenile hormone receptor complex proteins (MET and FISC). It has been reported that plants may use IGRs in their defenses against insect herbivores. In this study, 171 plant essential oil samples were screened using the yeast-two hybrid system in order to identify JHAs and/or JHANs. Eight out of 171 samples, 4 JHA and 4 JHAN candidates, were selected and their insecticidal activities were investigated against A. aegypti larvae. They showed high levels of insecticidal activities, with LC50 values ranging from 11.2~21.4 ug/ml. These results indicate that plants do use JHAs and/or JHANs as a part of their defenses against insect herbivores. Also, JHAs and JHANs identified in this study could be exploited as effective biological control agents.
        47.
        2015.10 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. IGRs are categorized into three types based on their mode of action. One of the them is classified as juvenile hormone agonists (JHAs). Recently, we developed a yeast-two hybrid system that can identify potential juvenile hormone antagonist (JHAN) candidates using Aedes aegypti juvenile hormone receptor complex proteins, known as MET and FISC. In order to identify novel JHAN compounds, approximately 8,700 basic chemical compounds were screened using the yeast-two hybrid system. Among them, 35 compounds were first selected based on consistency of JHAN activity, and their insecticidal activities were investigated against A. aegypti larvae. These compounds showed insecticidal activities about 1.7~3 times higher than that of pyriproxifen, which is a well known JHA insecticide. These results suggested that these JHANs can be used as effective JHAN insecticides.
        48.
        2015.10 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 systems become the targets of two types of IGRs: the Juvenile Hormone Agonists (JHAs) and Juvenile Hormone Antagonists (JHANs). Pyriproxyfen is one of the chemical compounds widely used as JHA to control many kinds of insects while Kanakugiol is a plant-extracted compound which acts as JHAN. The small brown planthopper, Laodelphax striatellus, is one of the most serious pest insects of rice plants because it can transmit the rice stripe virus which often causes significant reduction of yield in the field. In order to analyze the differential gene expressions of L. striatellus upon JHA and JHAN treatment by using next generation sequencing technique, we sprayed Pyriproxyfen and Kanakugiol on 4th instar nymphs of L. striatellus respectively, and extracted total RNA for RNA-seq. The quality-filtered Illumina sequence reads of the control, JHA, and JHAN treated samples were mapped to the reference gene sequences by using the Bowtie2 software. Then the results of mapping by Bowtie2 were analyzed by eXpress software to quantity the differential gene expression.
        49.
        2015.10 구독 인증기관·개인회원 무료
        Recently, Bacillus thuringiensis (Bt) cry genes encoding insecticidal Cry proteins have been widely applied for the construction of transgenic crops resistant to insect pests. This study aimed to construct novel mutant cry1Ac genes for genetically modified crops with enhanced insecticidal activities. Using multi-site directed mutagenesis, 34 mutant cry1Ac genes were synthesized and converted at 24 amino acid residues, located on domain I (8 residues) and domain II (16 residues). These mutant genes were expressed as a fusion protein with polyhedrin using the baculovirus expression system. The expressed proteins were occluded into polyhedra and activated stably to 65 kDa by trypsin. Among these, Mut-N04, N06, and N16 showed high levels of insecticidal activites against larvae of Plutella xylostella, Spodoptera exigua, and Ostrinia furnacalis. Mut-N16, which showed the highest insecticidal activity, is expected to be a desirable cry gene for introduction into transgenic crops. This study could provide useful means to construct mutant cry genes with improved insecticidal activities and expanded host spectrum for transgenic crops.
        50.
        2014.10 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) is an universal gene-knockdown mechanism in eukaryotic organisms which includes insects,and has been considered as an alternative strategy to control insect pests. Hence, we applied this technique to interfere the translation of target RNA genes to knockdown the virus gene on RSV-viruliferous L. striatellus. Three out of seven RSV genes, RdRp, NS3, and NCP were used as target genes and each dsRNA targeting the viral genes were delivered to the insects indirectly through the rice leaves by irrigation. As a result, not only the relative expression level of target genes decreased but also those of non-target genes and the replication of RSV genome as well. In summary, leaf-mediated dsRNA feeding methods would be useful in the knockdown of target genes on piercing-sucking insects. The genes used in this experiment can be utilized for the development of pest-resistant transgenic plants based on RNAi.
        51.
        2014.10 구독 인증기관·개인회원 무료
        Crystals of proteinaceous insecticidal proteins, Cry proteins, produced by Bacill us thuringiensis (Bt) have been generally used used to control insect pests. In this st udy, 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 Plutella xylostella, Spodopt era exigua and Ostrinia furnacalis were identified. To construct novel cry genes wi th enhanced insecticidal activity, we randomly mutated these 24 amino acid sequen ces by in vitro muti site-directed mutagenesis, resulting in totally 34 mutant cry gen es. 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 in to polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activit ies of these mutant Cry proteins against to larvae of P. xylostella, S. exigua, and O. furnacalis were assayed, they showed higher or similar insecticidal activity compar ed to those of Cry1Ac and Cry1C. Especially, among them Mutant-N16 showed th e highest insecticidal activity against to both of P. xylostella, S. exigua and Ostrinia furnacalis. Therefore, Mutant-N16 is estimated to have the potential for the efficac ious bioagent.
        52.
        2014.09 구독 인증기관 무료, 개인회원 유료
        Oral exposure of humans by excess amounts of arsenic may cause disturbances of the reproductive system. In the present study, such exposure was modelled in rats, with the support of sperm principal parameters and histopa-thological observations. Male Sprague–Dawley rats were randomly divided into three groups where the group I was served as a normal control, group II was received sodium meta-arsenite as arsenic (10 mg/kg b.w/day) and a combi-nation of sodium meta- arsenite and sodium selenite (3 mg/kg b.w/day) in group III. After 6 weeks, there was no significant change in testis weight and in total motility of all the three experimental groups, whereas, rapid moving spermatozoa, moderately moving spermatozoa and slow moving spermatozoa were significantly decreased in arsenic treated rats as compared to control rats. The other sperm principal parameters like progressiveness, average path velocity, straightness linear velocity (VSL), curvilinear velocity (VCL), straightness, linearity sperm head elongation ratio, area, linearity amplitude of lateral head department (ALH) and beat cross frequency (BCF) were found to be reduced in arsenic intoxicated rats. These results are not correlated with the histological studies. On oral admini-stration of selenium ameliorated the adverse effects of arsenic as compared to arsenic alone treated rats. Our findings clearly demonstrate that administration of selenium could prevent some of the deleterious effects of arsenic in the testis.
        4,000원
        53.
        2014.07 구독 인증기관·개인회원 무료
        This study explores relationship between social responsibility in advertising and brand attitude in luxury products. This study investgates how psychological constructs of attitude towards advertising affect brand attitude and purchase intention of luxury brand consumer and how it can lead the sustainable development of luxury products. Consumers no longer purchase products only but depend on quality and price of product. With globalization and rapid growth, corporate social responsibility becomes important issue. And the advertising represents corporate image and management concept. More recently, and coinciding with some major corporate ethical disasters, many companies have been including sections on governance, ethical practice, and social responsibility (David S. Waller & Roman Lanis, 2009). According to David S. Waller & Roman Lanis (2009), Corporate social responsibility (CSR) disclosure has been the subject of substantial academic accounting research (Farook and Lanis 2005; Gray, Owen, and Maunders 1987). Advertising is one of the typical means that can represent a corporate image. As defined by Lutz (1985, p. 53), attitude toward advertising in general is “a learned predisposition to respond in a consistently favorable or unfavorable manner to advertising in general.” In his framework, Lutz viewed attitude toward advertising in general as being directly influenced by general perceptions of advertising (Srinivas Durvasula et al., 1993). Authors would like to study following issues in this research. (1) How perceived social responsibility influences Attitude toward advertising. (2) How fashion consumer behavior influences Attitude toward advertising. (3) How attitude toward advertising affects brand attitude and purchase intention. (4) How proximity plays a moderating role among perceived social responsibility, attitude toward advertising and brand attitude.
        54.
        2014.04 구독 인증기관·개인회원 무료
        The Asian honeybee, Apis cerana, is a native honeybee species in Korea which is important in agriculture for pollination and honey production. For better understanding of the physiology of A. cerana, high-throughput Illumina transcriptome sequencing was performed to analyze the gene expression profiles of queen, worker and larva. A total of 219,799,682 clean reads corresponding to 22.2Gb of nucleotide sequences was obtained from the whole body total RNA samples. The Apis mellifera reference mRNA sequence database was used to measure the gene expression level with Bowtie2 and eXpress software and the Illumina short reads were mapped to 11,459 out of 11,736 A. mellifera reference genes. Total of 9,221 genes with FPKM value greater than 5 of each sample group were subjected to evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) with BLASTX for gene ontology analysis. The differential gene expression between queen and worker, and worker and larva were analyzed to screen the overexpressed genes in each sample group. in the queen and worker sample group, total of 1,766 genes were differentially expressed with 887 and 879 genes overexpressed over two folds in queen and worker, respectively. In the worker and larva sample group, total of 1,410 genes were differentially expressed with 1,009 and 401 genes overexpressed over two folds in worker and larva, respectively.
        55.
        2014.04 구독 인증기관·개인회원 무료
        Rice stripe virus (RSV) is one of the serious plant pathogenic viruses for rice and mediated by small brown planthopper, Laodalphax striatellus. So far, the studies have been mainly focused on the interaction between the host plant and the virus. In this study, for better comprehension of the interactions among Rice stripe virus, rice and small brown planthopper, transcriptomes of the RSV-viruliferous (RVLS) and non-viruliferous L. striatellus (NVLS) were comparatively analysed. For this, non-viruliferous L. striatellus were collected from non-infected rice field and fed RSV-infected rice for 5 days. With the RNAs prepared from the RSV-viruliferous and the non-viruliferous small brown planthoppers, we conducted Illumina RNA sequencing (Hiseq 2000) and then two transcriptome databases were generated from RVLS and NVLS, respectively. The transcriptome of RVLS and NVLS were campared to figure out how the gene expression of the insects affected by Rice Stripe Virus. RSV-dependently regulated genes analysed from this study may have important functions in the transmission and replication of RSV.
        56.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analysis of muscle fatigue in the upper trapezius and splenius capitis muscles according to therapy table height variation. The subjects were consisted of 15 healthy adults(10 males, 5 females) who had no medical history of neurological and musculoskeletal problems. In experiment, wireless electrode EMG system was measured for each the upper trapezius and splenius capitis muscles during the treatment performed on table. the differences in the muscle fatigue was compared for 4 types of table height(-6cm, -3cm, 0, +3cm from elbow in 90° flexion position). Muscle fatigue according to therapy table height were significant difference except for left upper trapezius. And muscle fatigue of right upper trapezius and splenius capitis showed significant decrease in +3cm table height compared to -6cm table height(p<.05). Muscle fatigue of right upper trapezius and splenius capitis were the highest in -6cm table height, but those were the lowest in +3cm table height. This study propose to change therapy table height higher than +3cm from elbow in 90° flexion position, if you hope to reduce muscle fatigue.
        4,000원
        57.
        2013.04 구독 인증기관·개인회원 무료
        Mealworms, Tenebrio molitor (L.) is used as an important animal feed additive for growth promotion and health management, but potentially exposes to fungal infection. In this work, virulence of two species of entomopathogenic fungi against the insect, and the relationship between abiotic features and virulence were investigated. Secondly our consideration was also given to the effect of chemical fungicides on conidial germination for risk control. Between Beauveria bassiana (Bb) and Metarhizium roberstii (Mr) (previously M. anisopliae), Bb isolates had much higher virulence (~100% mortality in 3~4 days after the treatment), rather than Mr isolates in laboratory assays. Next, fungus-treated mealworms were kept at wheat bran at 20, 25, 30 and 35℃ with 3, 6, 9 times of water spray to the feeds for set-up of different humidity conditions. Inoculation of fungi to mealworms was conducted by fungal spray and feeding methods, which resulted in higher virulence in feeding method. In the feeding method, all temperature treatments except 35℃ showed high virulence against mealworms, but any significant relationship between virulence and humidity was not observed. In the chemical fungicide screening, fluazinam (CAS No. 79622-59-6) and mancozeb (8018-01-7) significantly inhibited the germination of Bb and Mr conidia. This work suggest that contamination of wheat bran with fungal pathogens, particularly B. bassiana may induce mycosis of mealworms, but introduction of effective fungicides possibly reduce fungal infection.
        59.
        2012.06 구독 인증기관·개인회원 무료
        INTRODUCTION In rodent, molecular markers of spermatogonia, spermatocyte, spermatid and sperm have been identified. It has been reported that DBA, PGP 9.5 and NanpG can be the markers for spermatogonia in pig. For further understanding the spermatogenesis of the pig on morphological and molecular level, we report identification of testicular cells in neonatal and pubertal pig testis, and a putative marker for spermatogonia and spermatid in pig testis. MATERIALS AND METHODS Neonatal (3 day) and pubertal testis (150 day) was cut and fixed in Bouin’s solution for immunohistochemistry (IHC). Gonocytes were isolated from neonatal testis for immunocytochemistry (ICC). Based on references (Phillips et al., 2010), thirteen antibodies (VASA, Oct4, NanoG, PGP 9.5, DAZL, SCF, GFR-alpha 1, PLZF, c-kit, integrin-beta1, Thy1, Sohlh1 and CD9) were used for IHC and ICC. Paraffin section was performed for IHC. Gonocytes were attached to the APS-coated slides for ICC. HRP-conjugated and florescent-labeled secondary antibody was used for IHC and ICC, respectively. RESULTS In histological analysis, spermatogonia and Sertoli cells, which are enclosed by seminiferous tubule and connective tissue, were observed in neonatal testis. However, complete spermiogenesis, including spermatocyte, spermatid and spermatozoa, was not observed in neonatal testis. Spermatocyte, spermatid and elongated spermatid were observed in pubertal testis but matured spermatozoa were not observed. As a result, two antibodies (PGP 9.5 and GFR-alpha1) of thirteen antibodies were available for IHC and ICC. As reported in other studies, PGP 9.5 protein was detected in spermatogonia of ne-onatal in IHC. In addition, it was observed in spermatogonia of pubertal testis. GFR- alpha1 protein was detected in spermatogonia of neonatal testis and spermatid of pubertal testis. In ICC, PGP 9.5 protein was detected in gonocytes as reported in other studies. GFR-alpha1 was also observed in gonocyte isolated from pig testis. In this study, we found that 1) only spermatogonia exist in neonatal pig testis (3 day), 2) GFR-alpha1 is a new marker for spermatogenesis in pig testis.
        60.
        2012.06 구독 인증기관·개인회원 무료
        Interferon induced transmembrane protein-1 (IFITM1) is one of transmembrane protein which is differentially expressed in uterus during estrus cycle and pregnancy, that IFITM1 gene is highly expressed in estrus stage by the effect of estrogen, and in parturition by the effect of PGF2 alpha. This genes are also up-regulated in cells with hyperactivation of the WNT/β-catenin signaling pathway. In this study, to identify a function of IFITM1, the binding partner of IFITM1 were determined using immunoprecipitation and LC- MASSMASS methods. 1, 3 and 5 ug of polyclonal anti-IFITM1 antisera were used for immunoprecipitation, and the 75 kDa of specific band was detected in silver stained polyacylamide gel. This band were chracterized using LC-MASS-MASS, and revealed this band is glucose regulated protein 75 (GRP75) which binds to p53 and inhibits the p53 action in nucleus. To identify the localization of GRP75 in cells, immunocytochemical approach has been applied, and GRP75 is expressed in mitochondria of L929 murine connective tissue cells. Co-localization study between IFITM1 and GRP75 in L929 cell identified that these two proteins were closely expressed in mitochondria. Although the role of the interaction of these two protein need to be clarified in various biological phenomena, this data suggest that close interaction of IFITM1 and GRP75 may regulate cellular functions in uterus on sets of estrus cycle and pregnancy.
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