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        검색결과 644

        262.
        2014.04 구독 인증기관 무료, 개인회원 유료
        Beta-catenin (CTNNB1, catenin (cadherin-associated protein), beta 1) is involved in various biological processes, including embryogenesis, tumorigenesis, angiogenesis and progression of metastasis. CTNNB1, as a multifunctional and oncogenic protein, has important roles in adhesion between Sertoli cells through an N-cadherin-dependent manner and in various cancer types through its over-activation. In addition, CTNNB1 can interact with estrogen/estrogen receptor alpha complex, which regulates the transcription of WNT (wingless-type MMTV integration site family)/CT-NNB1 target genes. Recently, we investigated the functional roles and expression pattern of CTNNB1 during the morphological changes of embryonic gonads of chickens and the estrogen-dependent regulation of CTNNB1 in oviduct development and potential functions as a biomarker of CTNNB1 in human epithelial ovarian cancer using the chicken as a biological research model. Therefore, in this review, we provide a new insight of potential role of CTNNB1 in the development of the female reproductive tract during early embryogenesis and ovarian carcinogenesis of laying hen models.
        4,000원
        264.
        2014.04 구독 인증기관 무료, 개인회원 유료
        The majority of early embryonic mortality in pregnancy occurs during the peri-implantation stage, suggesting that this period is important for conceptus viability and the establishment of pregnancy. Successful establishment of preg-nancy in all mammalian species depends on the orchestrated molecular events that transpire at the conceptus- uterine interface during the peri-implantation period. This maternal-conceptus interaction is especially crucial in pigs because in them non-invasive epitheliochorial placentation occurs, in which the pre-implantation phase is prolonged. During the pre-implantation period, conceptus survival and the establishment of pregnancy are known to depend on the developing conceptus receiving an adequate supply of histotroph, which contains a wide range of nutrients and grow-th factors. Evidence links growth factors including epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), vascular endothelial growth factor (VEGF), and colony-stimulating factor 2 (CSF2) to embryogenesis or implantation in various mammalian species; however, in the case of pig, little is known about such functions of these growth factors, especially their regulatory mechanisms at the maternal-conceptus interface. Our research group has presented evidence for promising growth factors affecting cellular activities of primary porcine trophectoderm (pTr) cells, and we have identified potential intracellular signaling pathways responsible for the activities induced by these factors. Therefore, this review focuses on promising growth factors at the maternal-conceptus interface regulating the develop-ment of the porcine conceptus and playing pivotal roles in implantation events during early pregnancy in pigs.
        4,600원
        265.
        2013.10 구독 인증기관·개인회원 무료
        Proteinaceous insecticidal proteins, Cry proteins, from Bacillus thuringiensis (Bt) are insecticidal proteins that are highly active against several species of Lepidoptera. Thus, cry genes encoding these Cry proteins have been widely applied for construction of transgenic crops resistant to pest insects. In this study, 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 Spodoptera exigua and Ostrinia furnacalis were identified. We used site-directed mutagenesis to improve the insecticidal activity of Mod-Cry1Ac, resulted 31 mutant cry genes. These mutant cry genes encodes potent insecticidal proteins in the form of crystalline protoxins of 95 kDa. SDS-PAGE analysis of the recombinant polyhedra revealed that expressed Cry proteins was occluded into polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activities 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 compared to those of Cry1Ac and Cry1C. Especially, Mutant-N16 is considered to have the potential for the efficacious biological insecticide since it showed the highest insecticidal activity.
        266.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An in vitro study was conducted to determine the effects of defaunation (removal of protozoa) and forage sources (rice straw, ryegrass and tall fescue) on ruminal fermentation characteristics, methane (CH4) production and degradation by rumen microbes. Sodium lauryl sulfate, as a defaunation reagent, was added into the mixed culture solution to remove ruminal protozoa at a concentration of 0.375 mg/ml. Pure cellulose (0.64 g, Sigma, C8002) and three forage sources were incubated in the bottle of culture solution of mixed rumen microbes (faunation) or defaunation for up to 24 h. The concentration of ammonia-N was high under condition of defaunation compared to that from faunation in all incubations (p<0.001). Total VFA concentration was increased at 3, 6 and 12 h (p<0.05~p<0.01) but was decreased at 24 h incubation (p<0.001) under condition of defaunation. Defaunation decreased acetate (p<0.001) and butyrate (p<0.001) proportions at 6, 12 and 24 h incubation times, but increased propionate (p<0.001) proportion at all incubation times for forages. Effective degradability of dry matter was decreased by defaunation (p<0.001). Defaunation not only decreased total gas (p<0.001) and CO2 (p<0.01~0.001) production at 12 and 24 h incubations, but reduced CH4 production (p<0.001) at all incubation times for all forages. The CH4 production, regardless of defaunation, in order of forage sources were rice straw > tall fescue > ryegrass > cellulose (p<0.001) up to 24 h incubation.
        4,000원
        267.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of environmental and nutritional requirement such as temperature, pH, different media, carbon, nitrogen, and carbon-to-nitrogen ratio on the mycelial growth of Cordyceps militaris strain ‘Yedang 3’ were studied. The optimum temperature and pH for the growth of mycelium were 20-25oC and pH 6-7, respectively. Out of ten media tested, mushroom complete media (MCM) was the best medium for fast mycelial growth, and Sabouraud’s dextrose agar yeast extract (SDAY), malt extract yeast extract agar (YMA) also were favored. The color and shape of colonies varied in different media. The best carbon sources for mycelial growth were fructose, mannitol, and sucrose, whereas the best nitrogen sources were tryptone and peptone. However, mycelia grew slowly in inorganic nitrogen compounds such as NH4Cl, (NH4)2SO4, NH4NO3, and NaNO3. The optimum C:N ratio observed on the culture media was 30-40 range. These results provided basic information on cultural characteristics of vegetative growth and might be useful for spawn production in Cordyceps militaris.
        4,000원
        268.
        2013.08 구독 인증기관·개인회원 무료
        The purpose of this study is observing the process of learning Chinese character of preschool children and clarifying their language ability and the level and range of vocabulary. This paper sees the process of Korean children acquiring vocabulary in two ways: The first one is researching the vocabularies used in children's stories that preschool children often read or hear. The other one is researching the vocabularies that children hear or speak in the conversation with surroundings. To this end, two methodologies have been adopted: literature analysis and observation analysis. Literature analysis is investigating the fairy tales that children likes and analyzing the Chinese characters and vocabularies used. Observation analysis is recording the conversations between a child and his surroundings, and then transcribing and analyzing it. Almost every child reads fairy tales that helps to the formation of children's language ability. Therefore, the language of children's stories is the expectancy which Korean society expects children to understand the accomplished living environment and culture to. Therefore, children contact the basic cultural vocabulary in Korean society, contacting fairy tales. Children develop their intelligence and language through engaging in the daily conversations with their parents and acquaintances. Although they are influenced by communications with their peers of the same age group, the contents and range of the language used in the context of their surroundings affect a lot more. Thus, the process of children's language acquisition is developed through the conversations with parents and acquaintances. It is very possible that the language ability of a child in a family is transferred by parents rather than the intelligence and the ability of the child. Consequently, studying children’s Chinese character vocabulary through the two processes, you can see how level of the Chinese character vocabulary that children contact and use is, what characteristics it has and how much the range of use is.
        269.
        2013.06 구독 인증기관 무료, 개인회원 유료
        AtSAGT1 encodes a salicylic acid (SA) glucosyltransferase enzyme that catalyzes the formation of SA glucoside and SA glucose ester. Here, the AtSAGT1 gene expression patterns were determined in AtSAGT1 promoter::GUS transgenic Arabidopsis plants. As a result, the factors regulating the induction of AtSAGT1 were identified as pathogen defense response, wound response, exogenous application of SA, and jasmonic acid treatment.
        4,000원
        271.
        2013.05 구독 인증기관·개인회원 무료
        Lot-order assignment is the process of assigning items in lots being processed in a production facility to orders to meet due-dates of the orders. In this study, we consider the lot-order assignment problem (LOAP) with the objective of minimizing total tardiness of the orders with distinct due dates. We address similarity relationships between the LOAP and the single machine total tardiness scheduling problem (SMTTSP) and suggest priority rules for the LOAP based on those for the SMTTSP. Performances of the priority rules are compared with each other and with that of the commercial optimization software package in computational experiments.
        272.
        2013.04 구독 인증기관·개인회원 무료
        Crystals of proteinaceous insecticidal proteins, Cry proteins, produced by Bacillus thuringiensis (Bt) have been generally used to control insect pests. In this study, 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 Spodoptera exigua and Ostrinia furnacalis were identified. To construct novel cry genes with enhanced insecticidal activity, we randomly mutated these 23 amino acid sequences by in vitro muti site-directed mutagenesis, resulting in totally 24 mutant cry genes. 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 into polyhedra and activated stably to 65 kDa by trypsin. When the insecticidal activities of these mutant Cry proteins against to larvae of P. xylostella and S. exigua were assayed, they showed higher or similar insecticidal activity compared to those of Cry1Ac and Cry1C. Especially, among them Mutant-N16 showed the highest insecticidal activity against to both of P. xylostella and S. exigua. Therefore, Mutant-N16 is considered to have the potential for the efficacious biological insecticide.
        273.
        2013.03 구독 인증기관 무료, 개인회원 유료
        Ovarian cancer is the most lethal world-wide gynecological disease among women due to the lack of molecular biomarkers to diagnose the disease at an early stage. In addition, there are few well established relevant animal models for research on human ovarian cancer. For instance, rodent models have been established through highly specialized genetic manipulations, but they are not an excellent model for human ovarian cancer because histological features are not comparable to those of women, mice have a low incidence of tumorigenesis, and they experience a protracted period of tumor development. However, the laying hen is a unique and highly relevant animal model for research on human ovarian cancer because they spontaneously develop epithelial cell-derived ovarian cancer (EOC) as occurs in women. Our research group has identified common histological and physiological aspects of ovarian tumors from women and laying hens, and we have provided evidence for several potential biomarkers to detect, monitor and target for treatment of human ovarian cancers based on the use of both genetic and epigenetic factors. Therefore, this review focuses on ovarian cancer of laying hens and relevant regulatory mechanisms, based on genetic and epigenetic aspects of the disease in order to provide new information and to highlight the advantages of the laying hen model for research in ovarian carcinogenesis.
        4,000원
        274.
        2013.03 구독 인증기관 무료, 개인회원 유료
        Artificial insemination (AI) has been performed widely in swine industry using fresh liquid sperm instead of frozen type of sperm. However fresh sperm are not able to preserve more than three days with optimal motility and other sperm parameters for the successful fertilization, since in vitro stored sperm has an oxidative stress that resulted increase of abnormality and acrosome reation. To overcome these major problems, novel preservative formulation is needed to neutralize the oxidative stress and to provide suitable physiological environment for sperm in in vitro. In this study, naturally derived substances such as Poncirus trifoliate (Trifoliate orange), Garcinia mangostana (Mangosteen), pig placenta and testis extracts were tested as sperm preservative agents. Placenta extracts (PE), trifoliate orange extracts (TOE), testes extracts (TE) and mangosteen extracts (ME) were applied to analyze specific parameters for sperm motion characteristics individually and combinatorial. Each individual extract treatment can accelerate the sperm motility but noticeably TOE, TE and ME treatments exhibited the considerable and significant preservation of sperm motility. PE, TE and ME showed a significant (p<0.05) increase in ALH after one week. Further we evaluated the five different combinations of these extracts on sperm motility and its motion characteristics. Surprisingly even after one week ME, TOE and TE combination significantly preserved the sperm motility about 75%. It is noteworthy that unlike individual extract treatment, combination of ME, TOE and TE simultaneously protect the sperm motility and its motion characteristics. Taken together these data conclude that addition of ME, TOE and TE can be effective for preservation of pig sperm.
        4,000원
        275.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Inter-granular Bright Points (igBPs) are small-scale objects in the Solar photosphere which can be seen within dark inter-granular lanes. We present a new algorithm to automatically detect and extract igBPs. Laplacian and Morphological Dilation (LMD) technique is employed by the algorithm. It involves three basic processing steps: (1) obtaining candidate "seed" regions by Laplacian; (2) determining the boundary and size of igBPs by morphological dilation; (3) discarding brighter granules by a probability criterion. For validating our algorithm, we used the observed samples of the Dutch Open Telescope (DOT), collected on April 12, 2007. They contain 180 high-resolution images, and each has a 85×68arcsec2 85×68arcsec2 field of view (FOV). Two important results are obtained: first, the identified rate of igBPs reaches 95% and is higher than previous results; second, the diameter distribution is 220±25km 220±25km , which is fully consistent with previously published data. We conclude that the presented algorithm can detect and extract igBPs automatically and effectively.
        4,000원
        276.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The button mushroom (Agaricus bisporus) is one of the most widely cultivated important edible mushroom species. In the breeding of new button mushroom, ‘Seolgang’ was developed by crossing two monokaryons ‘CM020913-27’ and ‘SSU423-31’. Because of the secondarily homothallism, only a small percentage of the basidia produce 3 or 4 spores, which are mostly haploid (n) and do not fruit. Single spore cultures derived from these types of spores produce a vegetative mycelium that also contain a variable number of genetically identical nuclei per cell called monokaryon. The lack of clamp connections between monokaryon and dikaryon required a series of mycelial culture and fruiting test. After crossing, hybrids were cultivated on a small scale and on a commercial scale at a farm. For this, the spawn was made by a commercial spawn producer and the spawned compost by a commercial compost producer. Mycelial growth of ‘Seolgang’ on CDA was better at 20℃ and 25℃ when it was compared with that of ‘505 Ho’. The mature cap shape of new strain ‘Seolgang’ is oblate spheroid and the immature cap shape is round to oblate spheroid. The cap diameter was 41.2 mm on average. In comparison with white strain ‘505 Ho’, the strain had a yield that was 9% higher. It produced fruiting bodies which had a higher weight on average per fruiting body and were 19% firmer with a good shelf life. Days of fruiting body were 3-4 days later than those of ‘505 Ho’. The physical characteristics such as elasticity, chewiness, adhesiveness were better than that of ‘505 Ho’. Genetic analysis of the new strain ‘Seolgang’ showed different profiles compared to ‘505 Ho’, CM02913-27, SSU413-31, when RAPD primers A02 and O04 were used.
        4,000원