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        검색결과 589

        421.
        2009.08 구독 인증기관·개인회원 무료
        Perennial ryegrass (Lolium perenne L.) is one of the most important grass species in the world's temperate zones. It is used as high-quality forage in pastures and for recreational use as turf in golf courses, lawns and parks. Genetic improvement of perennial ryegrass is difficult due to its self-incompatibility. Consequently, progress by conventional breeding can be slow. Genetic transformation is an alternative that permits direct introduction of useful genes into a plant's genome and is becoming a powerful tool to complement conventional breeding. To improve environmental stress tolerance and quality of perennial ryegrass by introducing better and useful genes into the genome, we have developed a rapid and efficient transformation system using Agrobacterium-mediated gene transfer system.
        422.
        2009.08 구독 인증기관·개인회원 무료
        In the present study, we have used an annealing-control-primer (ACP)-based differentially display RT-PCR method to identify salt-stress-induced differentially expressed genes (DEGs) in barley leaves. Using 120 ACPs, a total of 11 up-regulated genes were identified and sequenced. Temporal expression patterns of some up-regulated DEGs in response to salt stress were further analyzed by Northern blot analysis. The possible roles of these identified genes are discussed within the context of their putative role in response to salt stress. Thus, the identification of some novel genes-such as SnRK1-type protein kinase; 17 kDa, class I, small heat shock protein; and RNase S-like protein precursor genes-may offer a new avenue for better understanding the salt stress response in plants, knowledge which might be helpful for developing future strategies.
        423.
        2009.06 구독 인증기관 무료, 개인회원 유료
        Cytosolic Ca2+ is an important regulator of tumor cell proliferation and metastasis. Recently, the strategy of blocking receptors and channels specific to certain cancer cell types has emerged as a potentially viable future treatment. Oral squamous cell carcinoma is an aggressive form of cancer with a high metastasis rate but the receptor-mechanisms involved in Ca2+ signaling in these tumors have not yet been elucidated. In our present study, we report that bradykinin induces Ca2+ signaling and its modulation in the human oral squamous carcinoma cell line, HSC-3. Bradykinin was found to increase the cytosolic Ca2+ levels in a concentration-dependent manner. This increase was inhibited by pretreatment with the phospholipase C-β inhibitor, U73122, and also by 2-aminoethoxydiphenyl borate, an inhibitor of the inositol 1,4,5-trisphosphate receptor. Pretreatment with extracellular ATP also inhibited the peak bradykinin-induced Ca2+ rise. In contrast, the ATP-induced rise in cytosolic Ca2+ was not affected by pretreatment with bradykinin. Pretreatment of the cells with either forskolin or phorbol 12-myristate 13-acetate (activators of adenylyl cyclase and protein kinase C, respectively) prior to bradykinin application accelerated the recovery of cytosolic Ca2+ to baseline levels. These data suggest that bradykinin receptors are functional in Ca2+ signaling in HSC-3 cells and may therefore represent a future target in treatment strategies for human oral squamous cell carcinoma.
        4,000원
        424.
        2009.05 구독 인증기관·개인회원 무료
        A multiplex polymerase chain reaction (PCR) was developed for the simultaneous detection and differentiation among Nosema apis and Nosema ceranae in honeybee. Three sets of primers were selected from different genomic sequences to specifically amplify a 831 bp amplicon within the SSU rRNA gene, specific for both N. apis and N. ceranae (MSSR primer); a 375 bp amplicon within the SSU rRNA gene, specific for N. apis (NA primer); and a 1,131 bp amplicon within SSU rRNA gene, specific for N. ceranae (NC primer). Using the primers in conjunction (multiplex PCR) we were able to N. apis and N. ceranae and to differentiate between them. The sensitivity of this PCR assay was approximately 102 spores per milliliter. We proposed that the multiplex PCR was sensitive, specific and rapid tool that can serve as a useful differential diagnostic tool for detecting N. apis and N. ceranae in honeybee.
        425.
        2009.05 구독 인증기관·개인회원 무료
        Microsporidia are obligate fungal intracellular parasites of all animal taxa. Among them the genus Nosema (Nosematidae) is known as the most common entomopathogen. Of these parasites, the ribosomal organization is one of the most pronounced molecular characteristics. One type is the normalarrangement of small subunit (SSU)-internal transcribed spacer (ITS)-large subunit (LSU) in the DNA sequence order. The other is the reverse arrangement of LSU-ITS-SSU. The latter is assigned to be the ‘true’ Nosema in the Nosema/Vairimorpha clade. However, we found that the SSU sequence of a strain of Nosema species having the normal arrangement of its rRNA sequence seemed to be more closely related to the ‘true’ Nosemagroup. Consequently we have further analyzed the complete sequence of rRNA. The results imply that there might be arecombination event in its rRNA evolution and/or the strain may form a novel group near the ‘true’ Nosema group. Interestingly both SSU and LSU of the ‘true’ Nosema and others may be under different selection pressure. We have also found that the size of ITS is distinct between the ‘true’ Nosema and other microsporidian species within the Nosema/Vairimorpha clade. This feature should be a useful diagnostic tool to distinguish the ‘true’ Nosema from others in the clade.
        426.
        2009.05 구독 인증기관·개인회원 무료
        This study was conducted to investigate the distribution pattern, ecological characteristics and life cycle of the Black Soldier Fly (Hermetia illucens, BSF). The BSF was widely distributed throughout Korea. The insect was mainly found in the vicinity of and in cattle sheds, manure sheds, living waste dump grounds, and food waste dump grounds. Developmental characteristics of the BSF are as follows: the egg was long oval shaped of 887㎛ in the major axis and 190㎛ in the minor axis; it weighed 24㎍. Female oviposited ca. 1,000 eggs on average; eggs hatched in 81 hours under laboratory condition (27℃, 60% R.H.). The duration of the larval stage was approximately 15-20 days. The size of the last instar larvae was 21mm. The cuticle of the pupae gradually acquired red-brown color and the size of them was 19 mm. The pupal stage was shorter for females (16 days) than males (15 days). Adults were sized about 13-20mm long and black-colored. The life span of adult insects was 5-8 days for the first generation (June-July), 7-10 days for the second generation (Aug.-Sept.), and 13-18 days for the third generation (Sept.-Oct.). Mating started on the next day of emergence and actively occurred at the third day after emergence. Mating mostly occurred between 10:00 and 16:00 during which light intensity is highest. Egg-laying started on the third day and was most frequent from the fourth to the sixth day after emergence. Similar to mating time, females oviposited mostly between 10:00 and 16:00.
        428.
        2008.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have estimated the fractal dimension of the molecular clouds associated with the H ΙΙ region Sh 156 in the Outer Galaxy. We selected the 12CO cube data from the FCRAO CO Survey of the Outer Galaxy. Using a developed code within IRAF, we identified slice-clouds (2-dimensional clouds in velocity-channel maps) with two threshold temperatures to estimate the fractal dimension. With the threshold temperatures of 1.8 K, and 3 K, we identified 317 slice-clouds and 217 slice-clouds, respectively. There seems to be a turn-over location in fractional dimension slope around NP (area; number of pixel) = 40. The fractal dimensions was estimated to be D = 1.5 ∼ 1.53 for NP ≥ 40, where P ∝ AD/2 (P is perimeter and A is area), which is slightly larger than other results. The sampling rate (spatial resolution) of observed data must be an important parameter when estimating fractal dimension. Fractal dimension is apparently invariant when varying the threshold temperatures applied to slice-clouds identification.
        4,000원
        432.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        HI몰랄리티가 9.5 mol/kg-H2O인 HI의 전해-전기투석을 시판의 양이온교환막(CMB)을 이용하여 요오드의 존재하에 실험을 진행하였다. 수소이온 투과의 선택성을 증가시키기 위해, 막은 전자선 가속기를 이용하여 방사선 처리하였다. 방사선 처리한 막의 막특성(막 저항, 이온교환용량, 함수율)을 측정하였다. 각각의 방사선량에서 처리한 막의 2 mol/dm3의 KCl 용액에서 막저항, 이온교환용량과 함수율은 처리하지 않은 막과 거의 동등의 값을 가졌다. HI몰랄리티가 9.5 mol/kg-H2O인 HI의 전해-전투기투석을 75℃, 9.6 A/dm2에서 진행하였다. 전자선 가속기에 의해 방사선 처리한 양이온교환막은 처리하지 않은 막과 비교하여 고분자의 가교구조와 함께 수소이온투과의 높은 선택성을 가졌다.
        4,000원
        433.
        2007.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        방사성폐기물 심지층 처분 시스템의 성능과 안정성을 평가하기 위해서는 처분장 환경에서의 열적, 역학적, 수리적, 화학적 거동에 대한 이해와 함께 이들 상호간의 영향을 파악하여야 한다. 복잡한 수학 모델과 모델링 기법을 요하는 THMC 복합거동에 대한 해석을 보다 효과적으로 수행하기 위해 DECOVALEX 국제공동연구가 진행되고 있다. 1992년 이후 4단계에 걸친 국제공동연구를 통해 다양한 조건에서의 THMC 복합거동을 해석하는 기법이 개발되어 왔다. 본 연구에서는 DECOVALEX의 주요 내용 및 현황을 정리하고 향후 참여방안 및 참여효과에 대해 논의한다.
        4,900원
        434.
        2007.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo and have the capacity to differentiate into various types of cells in the body. Hence, these cells may potentially be an indefinite source of cells for cell therapy in various degenerative diseases including neuronal disorders. For clinical applications of human ES cells, directed differentiation of these cells would be necessary. The objective of this study is to develop the culture condition for the expansion of neural precursor cells derived from human ES cells. Human ES cells were able to differentiate into neural precursor cells upon a stepwise culture condition. Neural precursor cells were propagated up to 5000-fold in cell numbers over 12-week period of culture and evaluated for their characteristics. Expressions of sox1 and pax6 transcripts were dramatically up-regulated along the differentiation stages by RT-PCR analysis. In contrast, expressions of oct4 and nanog transcripts were completely disappeared in neural precursor cells. Expressions of nestin, pax6 and sox1 were also confirmed in neural precursor cells by immunocytochemical analysis. Upon differentiation, the expanded neural precursor cells differentiated into neurons, astrocytes, and oligodendrocytes. In immunocytochemical analysis, expressions of type III β-tubulin and MAP2ab were observed. Presence of astrocytes and oligodendrocytes were also confirmed by expressions of GFAP and O4, respectively. Results of this study demonstrate the feasibility of long-term expansion of human ES cell-derived neural precursor cells in vitro, which can be a potential source of the cells for the treatment of neurodegenerative disorders.
        4,000원
        435.
        2007.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고준위폐기물 기준처분시스템의 건전성과 처분안전성의 실험적 검증에 필수적 시설인 지하처분연구시설이 한국원자력연구원 부지 내에 건설되었다. 지하처분연구시설의 부지조사 결과에 대해 기술하고, 이 부지에 건설될 지하처분연구시설의 설계, 인허가, 건설 과정과 건설된 시설의 개요에 대해 하였다. 또 지하처분연구시설에서 수행 중인 현장실험에 대해 소개하였다.
        5,100원
        436.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Sociolinguistic Journal of Korea 14(1). The purpose of this study is to investigate whether there is any relationship between dialect use and ethnolinguistic identity among Korean dialect speakers. It is hypothesized that those who have a strong perception of group identity and consider their dialect as more valuable than those of other groups are more likely to accentuate their language with cognitive efforts. This hypothesis was tested through questionnaires administered to 85 adults from five different provinces who were speaking their own dialect though they resided in Seoul. As a consequence of the analysis, it was found that dialect users in Seoul did not greatly require cognitive efforts when conversing with other dialect speakers. However, the results indicate that those who speak their dialect in a multi-dialectal situation can have a stronger perception of their local identity than those who do not. Thus, this study confirms that language is related to identity. Further, when various factors were examined, birthplace and residence period showed a weak relationship with strength of ethnolinguistic identity. However, results concerning age were meaningful in that the older participants were found to have a stronger identification with their dialect than the younger participants.
        5,700원
        437.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Choi, Jin-sook. 2006. Who Accentuates an Inter-group Dialect in an Inter-dialectal Place? The Sociolinguistic Journal of Korea 14(1). The purpose of this study is to investigate whether there is any relationship between dialect use and ethnolinguistic identity among Korean dialect speakers. It is hypothesized that those who have a strong perception of group identity and consider their dialect as more valuable than those of other groups are more likely to accentuate their language with cognitive efforts. This hypothesis was tested through questionnaires administered to 85 adults from five different provinces who were speaking their own dialect though they resided in Seoul. As a consequence of the analysis, it was found that dialect users in Seoul did not greatly require cognitive efforts when conversing with other dialect speakers. However, the results indicate that those who speak their dialect in a multi-dialectal situation can have a stronger perception of their local identity than those who do not. Thus, this study confirms that language is related to identity. Further, when various factors were examined, birthplace and residence period showed a weak relationship with strength of ethnolinguistic identity. However, results concerning age were meaningful in that the older participants were found to have a stronger identification with their dialect than the younger participants.
        5,700원
        440.
        2006.03 구독 인증기관 무료, 개인회원 유료
        The primary cause of periodontitis is plaque-associated anaerobic gram-negative bacteria. As shown in the patients with defects in the number or function of neutrophils, innate immunity plays an important role in resistance to bacterial infection and periodontitis. Toll-like receptor 4(TLR4) is one of the key receptors that recognize the molecular patterns of microbes and initiate innate immune response. To understand the role of TLR4 in the pathogenesis of periodontitis, we investigated whether Asp299Gly of TLR4 mutation is associated with periodontitis in Korean population. Subjects for this study included 90 healthy subjects and 98 periodontitis patients. The Asp299Gly mutation was screened by PCR-Restriction Fragment Length Polymorphism(RFLP) of genomic DNA from blood cells using a primer that creates a NcoI restriction site only in the mutant allele. The Asp299Gly mutation was not found in all subjects tested. Our results suggest that the Asp299Gly mutation of TLR4 is very rare in a Korean population. Further mutation screening may be required to determine the role of TLR4 in the pathogenesis of periodontitis.
        4,000원