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        검색결과 460

        221.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However, the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast dif-ferentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)- positive multinucleated cells induced by 10 nM 1α,25(OH)2 D3 in a dose‐dependent manner. A cell viability test revea-led no marked cellular damage by up to 100 mM of xylitol. Exposure of osteoblastic cells to xylitol decreased RANKL, but not OPG, mRNA expression in the presence of 10-8 M 1α,25(OH)2D3 in a dose‐dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the co- culture system, was found to be dramatically decreased with increasing xylitol concentrations. RANKL and OPG proteins were assayed by ELISA and the soluble RANKL (sRANKL) concentration was decreased with an increased xylitol con-centration. In contrast, OPG was unaltered by any xylitol con-centration in this assay. These results indicate that xylitol inhibits 1α,25(OH)2D3-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.
        4,000원
        222.
        2013.05 구독 인증기관·개인회원 무료
        Ganoderma have been used in traditional medicine for thousands of years in Korea, China and Japan as well as in other regions of the world. Ganoderma species is known to grow on hardwoods, conifers, palms, old and declining trees, decay dead wood and stumps. Several species is cause serious diseases of plantation and other economically important tropical crops. It also has been reported to prevent and treat immunological diseases, including tumorigenesis, control of blood glucose levels, modulation of the immune system, hepatoprotection, bacteriostasis, and more. In the present study, we examined the effects of various Ganoderma species, including Ganoderma lucidum and Ganoderma neo-japonicum on nitric oxide inhibition activities, β-hexosaminidase secretions, and DPPH free radical scavenging capacities to compare the anti-inflammatory, anti-allergic, and antioxidant effects.
        223.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The microstructure evolution during sintering of the W-5 wt.%Cu nanocomposite powders was investigated for the purpose of developing a high density W-Cu alloy. The W-5 wt.%Cu nanopowder compact, fully-densified during sintering at 1623 K, revealed a homogeneous microstructure that consists of high contiguity structures of W-W grains and an interconnected Cu phase located along the edges of the W grains. The Vickers hardness of the sintered W-5 wt.%Cu specimen was Hv much higher than that ( Hv) of the conventional heavy alloy. This result is mostly due to the higher contiguity microstructure of the W grains compared to the conventional W heavy alloy.
        3,000원
        224.
        2013.04 구독 인증기관·개인회원 무료
        The physiology of parasitic wasp control of their lepidopteran hosts' not only includes injecting their egg but also various factors such as symbiotic virus. This study was focused on the investigation of sophisticated interaction between parasitoid (Diadegma fenestrale) and their host (Plutella xylostella) in P. xylostella larva at transcriptome level, to check whether it is parasitized or not. Short-read deep sequencing method (Hiseq2000) was used for the transcriptome analysis. De novo assembly of cDNA sequence data generated 196,081 contigs between 201bp and 15,853bp in length. Some detoxification enzymes such as cytochrome P450 and Immune-related genes such as antimicrobial peptides were up-regulated after parasitism. Expression of symbiotic ichnovirus genes was detected in parasitized larvae with 55 contigs identified from five ichnovirus gene families including vankyrin, viral innexin, repeat elements, a cysteine-rich motif, and polar residue rich protein. This investigation provides a detailed information on differential expression of P. xylostella larval genes and symbiotic ichnovirus genes following parasitization.
        225.
        2013.04 구독 인증기관·개인회원 무료
        The Diadegma fenestrale is known as parasitoid on potato tuber moth, Phthorimaea operculella and diamondback moth, Plutella xylostella. The Diadegma genus is reported to have symbiotic virus, ichnovirus, D. fenestrale Ichnovirus (DfIV) was identified from this species which is a first report. DfIV showed typical ichnovirus shape with two membranes surrounding the virus capsid. To identify DfIV genes, whole genome sequencing based on GS-FLX was conducted using purified total DfIV genomic DNA extracted from D. fenestrale calyx. About sixty ORFs were analyzed and several typical ichnovirus gene families were detected such as cys-motif, repeat element, vinnexin and vankyrin. Present study was focused on the gene expression patterns in two different lepidopteran hosts.
        226.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The key concept of nanopowder agglomerate sintering (NAS) is to enhance material transport by controlling the powder interface volume of nanopowder agglomerates. Using this concept, we developed a new approach to full density processing for the fabrication of pure iron nanomaterial using Fe nanopowder agglomerates from oxide powders. Full density processing of pure iron nanopowders was introduced in which the powder interface volume is manipulated in order to control the densification process and its corresponding microstructures. The full density sintering behavior of Fe nanopowders optimally size-controlled by wet-milling treatment was discussed in terms of densification process and microstructures.
        4,000원
        227.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농업유전자원센터에 보존되어있는 불가리아 재래종 고추 유전자원 61 점을 대상으로 농업형질을 조사하고, 22개의 분자마커(SSR marker)를 이용하여 불가리아 재래종 고추 유전자원의 유전적 다양성 및 집단분석을 통하여, 자원보존 및 효율적인 작물 육종을 위한 기초정보를 제공하고자 본실험을 수행하였으며 결과는 다음과 같다. 1. 파종 후 발아까지 소요일수는 최소 11일에서 최대 26 일,평균 16.9 일이었고 개화 소요일수는 최소 48일, 최대 65일, 평균 56.9일이었으며 성숙까지의 소요일수는 최소 73일, 최대 98일, 평균 90.7일이었다. 2. 농업형질의 특성을 바탕으로 PCA 분석을 이용하여 불가리아 고추의 다양성을 분석한 결과, 파종 후 개화까지의 소요일수에 따라 조생종, 중생종, 만생종 3개의 그룹으로 나눌 수있었다. 3. 61점의 고추자원에 대하여 22개 SSR 마커에 의해 나타난 대립유전자 (allele)수는 총 82개였다. 마커당 평균 allele수는 3.7 개였고, allele 수의 범위는 2개에서 5개로 확인되었다. 유전적 다양성을 나타내는 PIC 값의 범위는 0.061-0.636이었으며 평균 PIC 값은 0.349로 확인되었다. 4. 분자마커(SSR)를 이용하여 UPGMA, PCoA, STUCTURE 분석을 통한 고추의 다양성 및 집단 구조를 분석한 결과, 3개의 그룹으로 나뉘어졌다. 결론적으로, 농업형질 특성을 바탕으로 한 불가리아 재래종고추의 다양성과 분자학적 특성을 이용한 다양성 결과와는 차이가 있었다.
        4,000원
        228.
        2012.10 구독 인증기관·개인회원 무료
        To identify whether higher expression of carboxylesterase (CbE) E4 in Myzus persicae is due to gene duplication, gene copy number was determined by quantitative real-time PCR. In addition, to determine the actual protein concentration of CbE E4 and it activity, Western blotting and activity staining were conducted. CbE gene copy number was highly correlated with carbamate resistance ratio (r2=0.934). However, CbE E4 expression level was little correlated with insecticide resistance ratio (r2<0.046) and no apparent correlation was observed among the gene copy number, protein quantity and total activity of CbE E4. Therefore, it was assumed that not only quantitative changing but also qualitative alteration of CbE E4 occurred in M. persicae. To investigate any potential alteration of CbE E4, mutation survey was conducted by sequencing of CbE E4 from various local strains of M. persicae. G137D and W251L mutations have been known as the main mutations associated with structural change leading to resistance. Interestingly, a new G134C mutation, which is in proximity of G137D mutation, was identified in the oxyanion hole of CbE E4. To predict the functional role of this mutation in resistance, 3-dimensional structure modeling was conducted. In summary, CbE E4 appears to be involved in resistance to both pyrethroids and carbamates as a nonspecific hydrolase or sequestration protein in M. persicae.
        229.
        2012.09 KCI 등재 구독 인증기관·개인회원 무료
        We carry out a systematic study of Galactic supernova remnants (SNRs) using the AKARI Far Infrared Surveyor (FIS) survey data. The AKARI Infrared Astronomical Satellite observed the whole sky using the four FIS bands covering 50 to 180 microns with ~1 arcmin resolution. The all-sky coverage with high-spatial resolution provides an unprecedented opportunity to study diffuse, extended far-infrared (FIR) sources such as SNRs. We have searched for FIR counterparts to all 274 known Galactic SNRs, and investigate their FIR properties of identified SNRs. We report preliminary results of the study.
        230.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The GroEL heat-shock protein from Fusobacterium nucleatum, a periodontopathogen, activates risk factors for atherosclerosis in human microvascular endothelial cells (HMEC-1) and ApoE-/- mice. In this study, we analyzed the signaling pathways by which F. nucleatum GroEL induces the proinflammatory factors in HMEC-1 cells known to be risk factors associated with the development of atherosclerosis and identified the cellular receptor used by GroEL. The MAPK and NF-κB signaling pathways were found to be activated by GroEL to induce the expression of interleukin- 8 (IL-8), monocyte chemoattractant protein 1 (MCP- 1), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), E-selectin, and tissue factor (TF). These effects were inhibited by a TLR4 knockdown. Our results thus indicate that TLR4 is a key receptor that mediates the interaction of F. nucleatum GroEL with HMEC-1 cells and subsequently induces an inflammatory response via the MAPK and NF-κB pathways.
        4,000원
        231.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼 흰잎마름병균의 정확한 진단을 위하여 PCR용 진단 kit를 개발하였다. 본 PCR kit를 개발하기 위하여 벼 흰잎마름 병균 유전체 정보 중 phage-related integrase and transposase gene의 염기서열을 이용하여 프라이머를 각각 제작하였다. 프라이머 염기서열은 XOP-F (5-CGG TCT GCT CAA TGA GGA AGA-3)와 XOP-R2 (5-TGC AAT TGG TGT TCTCCA GG-3), XOT-F (5-GTC ATA GGT GAG GCT TCCC-3)와 XOT-R2 (5-AGT GCG ATC TTT CAG CAG G-3)로 벼 흰잎마름병균의 DNA를 401bp와 492bp를 증폭하게 제작하였다. PCR 증폭은 벼 흰잎마름병균만 증폭하였으며 다른 세균인 Escherichia coli, Agrobacterim, Pectobacterium caratovora subsp. cartovorum, P. atrosepticum, Pseudomonasputida, P. syringae, P. savastanoi pv. phaeolicola, P. savastanoipv. savastanoi and P. marginalis pv. Marginalis 등은증폭되지 않아 특이성이 인정 되었다. 본 프라이머로 병이 의심되는 벼잎과 논물에서 병원균을 3시간 이내에 검출할 수 있었다.
        4,000원
        232.
        2012.05 구독 인증기관·개인회원 무료
        The Diadegma fenestrale was known as parasitoid on potato tuber moth, Phthorimaea operculella and diamondback moth, Plutella xylostella. This species, genus Diadegma are first reported from Korea. DfIV showed typical ichnovirus shape which two membranes surround virus capsids. The genome contents of DfIV consist about sixteen double-stranded DNA segments ranging 2 to 6 kb. To identify DfIV genes, whole genome sequencing based on GS-FLX was conducted using purified total viral DNA extracted from D. fenestrale calyx. About sixty ORFs were analyzed and several typical polydna virus gene family detected such as cys-motif, rep, vinnexin and vankyrin. This is the first report of DfIV and these lepidopteran host immune suppression genes will be deeply identified.
        233.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Matrix metalloproteinases (MMPs) have been implicated in tissue development and re-modeling. Dynamic morphological changes of tooth germs reflect involvement of these enzymes during odontogenesis. The present study was performed to investigate expression and localization of MMP-2 and MMP-9, which have been known to have type IV collagenase activities, in rat tooth germs at different developmental stages. MMP-2 expression was increased gradually in the tooth germs from cap to crown staged germs at both transcription and translation levels. The localization of this molecule was detected in secretory ameloblasts and preameloblasts. The strong immunoreactivities were occasionally seen along the basement membrane between ameloblasts (or preameloblasts) and odontoblasts (preodontoblasts). However, weak reactivity was detected in odontoblasts and reduced enamel epithelium. The level of MMP-9 expression in the tooth germs was higher in cap stage than in crown staged germs at both transcription and translation levels. They were strongly expressed in both ameloblasts and odontoblasts. Even though reduced enamel epithelium after enamel formation and inner enamel epithelium at the cap stage exhibited weak reactivity, strong reactivity was detected in dental follicles and perifollicular tissues surrounding cap staged germs. These results suggested that MMP-2 may involve degradation of the basement membrane during hard tissue formation, whereas MMP-9 might be involved in remodeling of follicular tissues.
        4,000원
        234.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A voltammetric assay of phenol ions was investigated using three electrode systems of graphite pencil working, reference and counter electrodes. Under optimum analytical parameters, square wave stripping working ranges were attained at a mili range of 10~80 mg/L and a micro range of 20~90 ug/L using seawater electrolyte. The developed sensor was applied to tap water and the human body system of a smoker. It was found that the methods can be applied to in vivo fluid or medicinal diagnosis.
        4,000원
        235.
        2011.11 구독 인증기관·개인회원 무료
        Korea National Arboretum (KNA) is located in Gwangneung forest, between Namyangju-si and Pocheon-si, in Gyeonggi province. In KNA, there are 15 specialized plant gardens. The woody plants of 1,863 species and the herbaceous plants of 1,481 species have been maintained in these gardens for 500 years. KNA have suitable environments for fungal growth. Despite floral diversity in there, the intensive researches on fungal flora have not been studied to date. Therefore, in order to get informations on fungal flora, regular field trips were made to this area and fresh fungal specimens were collected from there for 48 days from May in 2007 to November in 2010. Total 1,522 higher fungal specimens were collected in Gwangneung forest. All the collected specimens were identified and classified in 8 classes, 19 orders, 69 families, 267 genera and 454 species, and deposited in the herbarium of Korea National Arboretum (KNA). Among the identified specimens, sixteenspecies were confirmed as new to Korea as follows: Cudoniella acicularis, Discina ancilis, Helvella costifera, Entoloma cephalotrichum, Entoloma lepidissimum, Mycena leptocephala, Naematoloma gracile, Sistotrema octosporum, Hydnellum peckii, Lachnellula calyciformis, Amanita cockeri f. roseotinctata, Micromphale foetidum, Mycena corynephora, Clitocybe lateritia, Physisporinus vitreus, and Datronia stereoides. Literature cited 1. 김현중, 한상국. 2008. 광릉의 버섯. 국립수목원. 420pp. 2. 今關六也, 本鄕次雄. 1987. 原色日本菌類圖鑑(I). 保育社. 325pp. 3. Breitenbach, J. and Kränzlin, Fred. 1984. Fungi of Switzerland: 1. Ascomycetes. Mykologia Luzern. 310pp. 4. Breitenbach, J. and Kränzlin, Fred. 1986. Fungi of Switzerland: 2. Non gilled fungi. Mykologia Luzern. 412pp. 5. Breitenbach, J. and Kränzlin, Fred. 1995. Fungi of Switzerland: 4. Agarics 2nd part. Mykologia Luzern. 368pp. 6. Singer, R. 1986. The Agaricales in Modern Taxonomy. Koeltz Scientific Books. 7. Smith, A. H., Smith, H. V. and Weber N. S. 1979. How to know the gilled mushrooms. Wm. C. Brown Company Publishers. pp. 27, 263, 286-287.
        237.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a cosmopolitan pest of agricultural and horticultural crops and causes serious economic damages. M. persica has rapidly developed resistance to a wide variety of insecticides, including pyrethroids. Target site insensitivity mechanism mediated by two mutations (L1014F and M918T) on the para-type voltage-sensitive sodium channel (vssc) is mainly responsible for pyrethroid resistance. To predict the vssc resistance allele frequency, quantitative sequencing (QS) protocol was established. Frequency prediction equations generated from the plots of signal ratios and amplification critical time showed a high correlation coefficient (r2>0.993), indicating its high accuracy in prediction. QS results revealed that the kdr-type L1014F mutation is only present in Pyeongchang strain. No field strains of M. persicae possessed the super-kdr type M918T mutation. However, a novel M918L mutation was found by genotyping approach. The allele frequencies of M918L and L1014F were 0% to 53% in populations examined, and the level of M918L mutation frequency was closely related with pyrethroid resistance. Therefore, QS-based detection of M918L mutation frequency should faciltate the monitoring of pyrethroid resistance in the field.
        238.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a serious pest of agricultural and horticultural crops all over the world. M. persica has rapidly developed resistance to a wide variety of insecticides, including carbamates. The E4/FE4 carboxylesterase is known to be involved in carbamate resistance. To compare the E4/FE4 carboxylesterase gene copy number, as a genetic resistance marker, between seven field strains, quantitative real-time PCR (qPCR) was performed. In addition, quantitative sequencing (QS) was employed to predict the frequencies of acetylcholinesterase (AChE) mutations (A301S and S431F) that are associated with target site insensitivity. All M. persica strains examined possessed the S431F mutation in the heterozygous state except for a susceptible strain, implying the possibility of AChE duplication. In contrast, no A301S mutation was found. Frequency prediction equation was generated from the plots of signal ratios and amplification critical time, which showed a high correlation (r2>0.996). QS analysis of M. persicae populations revealed that the allele frequency of S431F ranged 4% to 63%. Taken together, the AChE resistance allele frequencies determined by QS and the E4/FE4 gene copy number by qPCR should facilitate the detection and monitoring of carbamate resistance in M. persicae in the field.
        239.
        2011.10 구독 인증기관·개인회원 무료
        Larval stages of Callipogon relictus (Semenov) (Coleoptera: Cerambycidae), a gigantic longhorn beetle designated as a natural monument of Korea, has never been studied as it is hardly discovered in nature. The DNA barcoding gene, mt-COI, was used to identify a dead larva found in the Gwangneung forest of the Korea National Arboretum. Based on the result, we provide the morphology of the immature stage, with the illustrations of diagnostic characteristics.
        240.
        2011.05 구독 인증기관·개인회원 무료
        Insecticidal activity of active component isolated from Ruta chalepensis leaves was examined against maize weevil, Sitophilus zeamais and compared with two different bioassay system, such as direct contact and fumigant method. The methanol extract of R. chalepensis leaves had strongly (+++) insecticidal activity at 50 mg/disk against S. zeamais. Methanol extract of R. chalepensis was partitioned with hexane, chloroform, ethyl acetate, butanol and water fraction, successively. In this result, the highest activity was shown in chloroform fraction against S. zeamais. Biologically active compound derived from chloroform fraction of R. chalepensis extract was purified by using SiO2 column chromatography and prep-HPLC. The insecticidal constituent of R. chalepensis was identified as quinoline-4-carboxaldehyde by various chromatography and spectroscopic analysis methods. At 2.5 mg/disk, the most toxic activity against S. zeamais was exerted by the direct contact method (100%), followed by the fumigant method (23%). These results revealed that the contact toxicity showed 4.35 times greater than the respiration toxicity. Furthermore, these results indicate that quinoline- 4-carboxaldehyde could be useful as a new preventive agent against damage caused by stored-product insects.