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        검색결과 95

        42.
        2014.04 구독 인증기관·개인회원 무료
        Epigeic spiders (Araneae) were surveyed in apple orchards under different farming practices (organic and conventional) in Muju-gun, Jeollabuk-do, Korea. The study was conducted from April to October in 2013 with 2 weeks interval using pitfall traps. Collected spiders were identified as 20 species of 6 families from 819 individuals in organic orchardⅠ, 19 species of 10 families from 759 individuals in orchardⅡ and 16 species of 8 families from 209 individuals in conventional orchard for from 1,787 captured spiders. Biodiversity was analyzed with species richness, abundance and Shannon diversity index (H΄). Species richness was statistically higher in organic orchard than in conventional orchard. Organic orchardⅡ comprised the greatest abundance followed by organic orchard and conventional. But species diversity was the highest in organic orchardⅡ, intermediate in conventional orchard and the lowest in orchardⅠ. Lycosidae was the most dominant family in all orchards regardless farming practices. However, Linyphiidae dominated in organic orchards only. The most dominant species were Erigone koshiensis (Linyphiidae) in organicⅠ, Pardosa laura (Lycosidae) in organicⅡ and Arctosa pungcheunensis (Lycosidae) in conventional orchard.
        43.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscle satellite cell (SC) is responsible for postnatal muscle growth, repair, and regeneration. Satellite cell is an im-portant source of multi-potent stem cell process and differentiation into adipogenic, myogenic, and osteoblastogenic. The objective of this study was to identify alter of transcriptome during differentiation in porcine satellite cell and to elevated transcriptome at different stages of postnatal development to gain insight into the differences in differ-entiated PSC. We used RNA-seq technique to investigate the transcriptomes during differentiation in pig muscle. Sequence reads were obtained from Illumina HiSeq2000. Differentially expressed genes (DEG) were detected by EdgeR. Gene ontology (GO) terms are powerful tool for unification among representation genes or products. In study of GO biological terms, functional annotation clustering involved in cell cycle, apoptosis, extracellular matrix, phosphoryla- tion, proteolysis, and cell signaling in differences stage. Taken together, these results would be contributed to a better understanding of muscle biology and processes underlying differentiation. Our results suggest that the source of DEGs could be better understanding of the mechanism of muscle differentiation and transdifferentiation.
        4,500원
        44.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Satellite cells were derived from muscular tissue in postnatal pig. Satellite cell is an important to growth and development in animal tissues or organs. However, the progress underlying induced differentiation is not clear. The aim of this study was to evaluate the morphologic and the transcriptome changes in porcine satellite cell (PSC) treated with insulin, rosiglitazone, or dexamethasone respectively. PSC was obtained from postnatal muscle tissue. In study 1, for study the effect of insulin and FBS on the differentiated satellite cells, cells were cultured at absence or presence of insulin treated with FBS. Total RNA was extracted for determining the expression levels of myo-genic PAX3, PAX7, Myf5, MyoD, and myogenin genes by real-time PCR. Myogenic genes decreased expression levels of mRNA in treated with insulin. In study 2, in order to clarify the relationship between rosiglitazone and lipid in differentiated satellite cells, we further examined the effect of FBS on lipid accumulation in the presence or absence of the rosiglitazone and lipid. Significant differences were observed between rosiglitazone and lipid by FBS. The mRNA of FABP4 and PPARγ increased in rosiglitazone treatment. In study 3, we examined the effect of dexame-thasone on osteogenic differentiation in PSC. The mRNA was increased osteoblasotgenic ALP and ON genes treated with dexamethasone in 2% FBS. Dexamethasone induces osteoblastogenesis in differentiated PSC. Taken together, in differentiated PSCs, FABP4 and PPARγ increased to rosiglitazone. Whereas, no differences to FBS and lipid. These results were not comparable with previous reports. Our results suggest that adipogenic, myogenic, and osteoblasto-genic could be isolated from porcine skeletal muscle, and identify culture conditions which optimize proliferation and differentiation formation of PSC.
        4,000원
        45.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90∼100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson’s, oil red O, and Alizarin red staining respectively. We per-formed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator- acti-vated receptor gamma (PPARγ) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteo-blast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were indu-ced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strat-egies for augmenting meat quality.
        4,000원
        47.
        2013.10 구독 인증기관·개인회원 무료
        The centipede Scolopendra subspinipes mutilans has been a medically important arthropod species by using it as a traditional medicine for the treatment of various diseases. In this study, we derived a novel lactoferricin B like peptide (LBLP) from the whole bodies of adult centipedes, S. s. mutilans, and investigated the antifungal effect of LBLP. LBLP exerted an antifungal and fungicidal activity without hemolysis. To investigate the antifungal mechanism of LBLP, a membrane study with propidium iodide was first conducted against Candida albicans. The result showed that LBLP caused fungal membrane permeabilization. The assays of the three dimensional flow cytometric contour plot and membrane potential further showed cell shrinkage and membrane depolarization by the membrane damage. Finally, we confirmed the membrane-active mechanism of LBLP by synthesizing model membranes, calcein and FITC-dextran loaded large unilamellar vesicles. These results showed that the antifungal effect of LBLP on membrane was due to the formation of pores with radii between 0.74 nm and 1.4 nm. In conclusion, this study suggests that LBLP exerts a potent antifungal activity by pore formation in the membrane, eventually leading to fungal cell death.
        48.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기업의 지배구조 특히, 소유구조와 사외이사의 비율에 따라 구조화 파생상품의 이용여부가 영향을 받을 것이라는 가설을 실증분석 하였다. 기존의 파생상품에 비해 구조화 파생상품은 그 헤징효과가 불명확하며 오히려 기업들을 위험에 노출시킨다는 연구들이 있는데, 이를 바탕으로 하여 본 연구는 구조화파생상품 이용에 영향을 미치는 대주주와 외국인주주 및 사외이사의 역할을 확인하고자 하였다. 표본기간은 2005년부터 2009년까지이며 12월 결산법인인 상장제조기업 중 파생상품을 이용한 기업을 대상으로 로짓분석을 실시하였다. 구조화 파생상품 이용에 대한 로짓분석 결과 소유구조, 특히 대주주지분율은 파생상품 이용에 정(+)의 관계를 보이지만 대주주지분율의 제곱은 유의한 결과값을 보이고 있지 않아서, 기존 연구와는 달리 역-U자형 관계를 보여주지는 못했다. 이와 달리 외부감시자로써의 역할을 하는 5% 이상 보유 외국인 지분율 합계와 사외이사초과선임비율은 구조화파생상품 이용에 대해 음(-)의 계수값을 보였으며, 이로부터 복잡하지만 헤지 효과가 적은 구조화 파생상품 이용이 외국인과 사외이사에 의해서는 환영받지 못하는 것으로 보인다. 또한, 외국인 지분율 합계는 통계적으로 유의한 결과를 보이지 않는데 비해 개별적으로 5%이상 보유한 외국인지분율의 합계는 음(-)의 영향을 보이고 있으며, 이로부터 기존의 외국인 투자자에 대한 연구에서와 마찬가지로 일정 지분이상을 보유한 외국인의 감시역량이 상대적으로 우월함을 알 수 있다. 전년도 파생상품이용으로 인한 이익은 다음 연도 파생금융상품 이용에 긍정적인 영향을 줄 것으로 예측되었으나 실증결과는 오히려 반대의 결과를 보였다.
        5,800원
        49.
        2013.04 구독 인증기관·개인회원 무료
        In apple orchards under different farming practices (organic and conventional), arthropod community structure was investigated. Arthropods were collected with pitfall traps, band traps, yellow sticky traps and pheromone traps from May to December, 2012 in Danyang-gun, Chungcheongbuk-do, Korea. Biodiversity was analyzed with species richness and Shannon diversity index (H΄). Sampled arthropods were identified 37 families in 14 orders from 21,618 individuals in organic orchard-1 and 33 families in 10 orders from 11,318 individuals in organic orchard-2 and 35 families in 13 orders from 27,711 individuals in conventional orchard. Species richness was relatively highest in organic orchard-1, intermediate in conventional orchard and lowest in organic orchard-2. In ecologically functional group, abundance of pests was higher in conventional orchard than in organic orchards due to the high occurrence of Phyllonorycte ringoniella (Gracillariidae) and Lyonetia prunifoliella (Lyonetiidae). Organic orchards showed higher abundance, species richness and species diversity of epigeic predators and those of parasitoids above ground than conventional orchard. Abundance of detritivores, mainly collembola, were higher in organic orchard than in conventional orchard.
        52.
        2011.10 구독 인증기관·개인회원 무료
        A carbofuran-resistant strain (CAS) showed ca. 41.1- and 15.1-fold resistance compared to a susceptible strain (SUS) and a non-selected field strain (FM), respectively. Enhanced activities of carboxylesterase and P450 were found as ca. 3- and 1.6-fold higher in CAS strain, suggesting these enzymes play a minor role in carbofuran resistance. Interestingly, the insensitivity of acetylcholinesterase (AChE) to carbofuran was revealed to be ca. 5.5- and 3.7-fold higher in CAS strain compared to, indicating that AChE insensitivity mechanism is associated with carbofuran resistance. In the western blot analysis, two kinds of AChEs were found and type-1 AChE (Nlace1) was identified as the major AChE in N. lugens. The open reading frame of Nlace1 is composed of 2,106 bp (ca. 78 Kd) and revealed 52.5% and 24.3% identity compared with Nephotettix cincticeps and Drosophila melanogaster, respectively. In the screening of point mutations, four amino acid substitutions (G119A, F/S330Y, F331I and H332L) were identified in the CAS strain that likely contribute to the AChE insensitivity. The allele frequencies of these mutations increased in the survived populations following the selection by LC50 of carbofuran, confirming that they are in fact associated with reduced sensitivity to carbofuran in N. lugens. These point mutation can be useful for the monitoring of resistance levels in conjunction with QS methods.
        53.
        2011.05 구독 인증기관·개인회원 무료
        The differences in the immune response between body lice, Pediculus humanus humanus, and head lice, Pediculus humanus capitis, were regarded as primary factors determining their differential vector competence. To find any differences in genetic components in immune system between body and head lice, whole genome sequences of head lice were determined by both SBS [sequencing by synthesis, Illumina Genome Analyzer (Illumina-GA)] and pyrosequencing (Roche GS FLX), and compared with the reference genome sequences of body lice. The short DNA reads from Illumina-GA (an average mapping depth of 50-fold) were aligned first to the body louse reference genome, to which Roche GS FLX DNA reads (an average depth of 2.5-fold) were subsequently assembled to make up gaps between mapped consensus. Total consensus showed a size of 114 Mb and a coverage of 96% of the published body louse genome sequences. From this head louse genome sequences, a total of 12,651 genes were predicted and used for comparing with the 10,775 genes previously reported from the body louse genome. The homolog analysis identified 873 head louse-specific genes and 422 body lice-specific genes. Comparison of immune response genes between both louse species showed head lice have more number of immune-related genes than body lice. Head lice were determined to possess all of the 107 immune-related genes reported in the previous study (Kim et al., 2011), suggesting that there is no difference in genetic make-up in terms of the 107 immune-related genes between body and head lice.
        54.
        2011.05 구독 인증기관·개인회원 무료
        Venom allergen-like protein 2 (Vap2) was characterized from the pinewood nematode, Bursaphelenchus xylophilus, which is a destructive pathogen in several countries including Japan, China and Korea. Among three vaps of B. xylophilus (Bx-vap)reported in GenBank, Bx-vap2 showed the highest transcript level in both pine-grown propagative stage (PGPS) and media-grown propagative stage (MGPS). Bx-vap2 also was revealed that its transcript level over 10-fold increased in PGPS. In addition, western blot using BxVap2-polyclonal antibody showed that expression level of BxVap2 was significantly increased in PGPS. In immunohistochemistry, moreover, strong signals were detected around putative subventral gland in PGPS, whereas weak signals were observed in MGPS. These experimental results suppose pathogenic function of BxVap2 and migration assay using Bx-vap2 knock-down worms by RNA interference supports this postulation.
        55.
        2011.05 구독 인증기관·개인회원 무료
        Damages by Tyrophagus spp. (Acari: Acaridae) on horticultural crops were newly observed in recent years especially in organic culture greenhouses in Korea. The crops damaged by the mite species were Spinacia oleracea L. (spinach), Cucumis sativus (cucumber), and Phalaenopsis schilleriana (orchid). The spinach inner leaf growth was halted affected by the feeding of Tyrophagus similis at the early stage of the shoot emergence. The young leaves of the spinach bud had small holes and the leaves were deformed as they grew up. The surface of young cucumber fruits became shiny and soft at the early damage stage and the damaged surfaces became corky as the plants grew up. The mite from cucumber was identified as Tyrophagus neiswanderi Johnston & Bruce. In phalaenopsis orchid, the flower buds became yellow and dropped and the lower side of the leaves had white spots. The damages were caused by Tyrophagus putrescentiae.
        57.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        에멀션 기반의 계면활성제를 이용한 주형합성법을 이용하여 산촉매로서 염산과 실리카의 전구체인 테 트라에톡시실란을 사용함으로써 메조다공성 실리카 마이크로스피어를 합성하였다. 테트라에톡시실란의 농도 증가에 의해 구형의 입자 형태가 파괴되었고, 기공구조도 크게 변하였다. 산촉매 농도 증가에 의한 구형의 입자형태 파괴 현상은 적었지만 상대적으로 작은 크기의 구형의 마이크로입자가 더 많이 생성되 었다. 하지만, 산성조건에서 입자들 간의 강한 응집현상이 나타남에 따라 낱개의 분리되어 있는 단일입자 를 얻기 위해서는 초음파 등의 후처리 과정이 필요하였다.
        4,200원
        58.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기업은 경쟁우위를 확보하고 지속적인 성장을 이끌기 위해 기술개발을 위한 R&D 투자 및 혁신활동에 집중해야 한다. 그러나, 기업의 이러한 활동은 언제나 성공하는 것이 아니며, 기술개발의 위험도가 높고 이익의 전용가능성이 낮거나 기업내부의 역량이나 자원이 부족할 경우, 기업의 혁신활동은 저해되기 쉽다. 이러한 상황에서 외부파트너와의 연구협력은 이러한 문제들을 해결할 수 있는 좋은 전략이라고 할 수 있다. 본 연구에서는 한국의 제조업체를 대상으로 각 기업이 기술혁신을 위해 연구협력을 선택할 때 어떤 요인들이 연구 협력결정에 영향을 미치는지를 분석하였다. 이를 위해서 과학기술정책연구원(STEPI)에서 수행한 기술혁신조사 데이터를 활용하였으며, 분석결과 기업의 규모가 클수록, 과거의 연구협력경험이 많을수록, 하이테크 기업에 속한 기업일수록 연구협력을 통해 제품혁신을 수행하는 것으로 나타났으며, 혁신실패의 위험성, 자금조달의 어려움, 조직내부의 역량부족, 외부환경요인 등과 같은 혁신활동저해요소들은 제품혁신활동 수행시 외부와의 연구협력에 영향을 미치지 못하는 것으로 나타났다.
        6,000원
        59.
        2010.05 구독 인증기관·개인회원 무료
        Three acetylcholinesterases (AChEs) were identified from the pinewood nematode, Bursaphelenchus xylophilus. Sequence comparison with known AChEs in conjunction with three-dimensional structure analysis suggested that all BxAChEs share typical characteristics of AChE at the major catalytic structures. BgAChE3 was most predominantly transcribed and then followed by AChE1 and AChE2. Immunohistochemistry using anti-BxAChEs antibodies revealed that BxAChE1 is most widely distributed whereas BxAChE2 exhibits more localized distribution in neuronal tissues. BxAChE3 was detected from entire body together with some limited tissues, including mouth parts and alimentary lining, and determined to be the only soluble AChE, suggesting its localization in hemolymph or/and extracellular space. Kinetic analysis of in vitro expressed BxAChEs revealed that BxAChE1 has the highest substrate specificity whereas BxAChE2 has the highest catalytic efficiency with BxAChE3 having the lowest catalytic efficiency. Interestingly, presence of BxAChE3 in the pool of BxAChEs significantly reduced the inhibition of BxAChE1 and BxAChE2 by inhibitors. Knockout of BxAChE3 by RNAi significantly increased the toxicity of nematicides, suggesting the protective role of BxAChE3 against these toxicants. Based on several features, including tissue distribution, expression level, substrate kinetics and inhibition property, it appeared that BxAChE1 is the major AChE with the function of postsynaptic transmission whereas BxAChE3 has been evolved to acquire the function of chemical defense, perhaps intrinsically against secondary toxic compounds from host pine trees, such as α-pinene and limonene. BxAChE2 appears to play a role in post-synaptic transmission in specialized neurons but its detailed physiological function still remains to be elucidated.
        60.
        2009.10 구독 인증기관·개인회원 무료
        Three acetylcholinesterase (ace) genes were identified from Bursaphelenchus xylophilus and named as Bxace1, Bxace2 and Bxace3. Open reading fragments of Bxace1, Bxace2 and Bxace3 were composed of 622, 625 and 588 amino acids, respectively. Sequencing comparison with Torpedo ace gene identified cholinebinding site, catalytic triad functional site, three internal disulfide bonds and aromatic residues for the catalytic gorge. Transcriptional profiling by quantitative real-time PCR revealed that Bxace3 is more actively transcribed than Bxace1 (2-3 times) and Bxace2 (9-18 times) in both propagative and dispersal stages. The three ace genes were functionally expressed using baculovirus system. Kinetic analysis using three choline substrates demonstrated that BxAce2 has higher maximum velocity than BxAce1 (ca. 2 times) and BxAce3 (ca. 100 times) whereas BxAce3 shows lower Michaelis constant than BxAce1 (12.8 times) and BxAce2 (13.6 times). In inhibition assay using five organophosphates (OPs) and three carbamates (CBs), all the three BxAces were highly inhibited by paraoxon, DDVP and chlorpyrifos-oxon but not inhibited well by fenamiphos and fosthiazate. Interestingly, inhibition assay revealed that BxAce3 is less sensitive to all insecticides tested than other two BxAces. The inhibition kinetic data obtained in this study should provide essential information for the development of OP- and CB-based nematicidal agents againt B. xylophilus.
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