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        검색결과 819

        527.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the pyrimidine derivatives were obtained in low yields ranging from 8% to 20%, we reported the successful preparation of N,N-diaryl-pyrimidin-2-amine derivatives starting from the corresponding 2-aminopyrimidines (1a-1c), by direct palladium-catalyzed arylation using different arylbromides. The reasons of low yields are thought to be the electronic and steric effects by the neighboring aromatic systems. The absorption spectra and photoluminescent spectra of compounds (3a 3g and 4a-4c) were measured using dichloromethane on the concentration of 25 mM by UV vis spectroscopy and luminescent spectroscopy. Pyrimidine derivatives 4a, 4b, and 4c showed moderate emission maxima at 474 nm, 481 nm, and 367 nm, respectively, while other compounds showed very weak photoluminescence or no photoluminescence at all.
        4,000원
        529.
        2008.06 KCI 등재 구독 인증기관·개인회원 무료
        The caterpillar-shaped Chinese medicinal mushroom (DongChongXiaCao) looks like a worm in the winter and likes a grass in the summer. The fruiting bodies of Cordyceps species have demonstrated various biological activities and used as traditional medicines in Asian countries. The price of wild Cordyceps have been ascending every year as their demand increase. Recently, the artificial cultivation of these fungi has been successfully established and they are currently produced on a rice or pupae media. This study was carried out to investigate the soluble sugar, amino acid and fatty acid profiles in the fruiting-bodies of Cordyceps militaris, C. pruinosa and Paecilomyces. tenuipes formed on the living silkworm (Bombyx mori) host. Soluble sugars such as glycerol, glucose, mannitol and sucrose were found in the fruiting bodies of Cordyceps militaris, C. pruinosa and P. tenuipes. Total soluble sugar content was 29.23 ㎎g-1in C. militaris, 8.61㎎g-1 in C. pruinosa and 24.00 ㎎g-1in P. tenuipes on dry weight basis. Total free amino acid content was 14.09 ㎎g-1in C. militaris, 34.60㎎g-1 in C. pruinosa and 17.09 ㎎g-1 in P. tenuipes. The content of oleic acid in fatty acids was above high more than 30% regardless of species.
        530.
        2008.06 구독 인증기관 무료, 개인회원 유료
        The present study was undertaken to identify changes of plasminogen activators (PAs) in porcine oviductal epithelial cells (POECs) during the estrous cycle classified with post-ovulatory stages (Post-Ov), early to mid-luteal stages (Early-mid L) and pre-ovulatory (Pre-Ov) stages. The urokinase-type plasminogen activator (uPA) was only observed on day 5 and day 7 of culture in the POECs on all the estrous cycles and gradually increased according to increasing culture times, but not Early-mid L. In POECs-conditioned medium, uPA, tissue-type (tPA) and tPA-PA inhibitor (tPA-PAI) activity were observed at all culture times during estrous cycles. The uPA activity of POECs-conditioned medium on Post-Ov stage were significantly (p<0.05) decreased during prolonged cultures. On the other hand, the tPA activity of POECs-conditioned medium at Post-Ov stage was significantly (p<0.05) higher on day 5 than compared to the other days. Although was higher on day 1 at Post-Ov stage, the tPA-PAI activity of POECs-conditioned medium was significantly (p<0.05) higher on day 7 at all stage than that of day 5 of the culture. Taken together, these results suggest that uPA, tPA and tPA-PAI are produced by POECs, and the variations of the PAs activity are regulated in the different stages of the estrous cycle.
        4,000원
        531.
        2008.06 구독 인증기관 무료, 개인회원 유료
        Production of transgenic animals for studying specific gene has been limited due to a low efficiency, lack of skilled researchers and the need for expensive equipment. Currently, the boar spermatozoa as a vector to deliver exogenous DNA into the oocyte were used to improve the efficiency of transfection rate. In this study, we revealed that the optimal conditions for DNA uptake in spermatozoa by liposome were to 90 min of incubation, 17'C, 10' spermatozoa, 4 ng/ml of exogenous DNA and 0.5% (v/v) liposome, without damage to fertility. In addition, the developmental rate to the blastocyst stage of embryo in control group was significantly higher than those embryos with exogenous DNA and liposome, whereas there were no significant differences in embryo development between the liposome and type of DNA. The transfection rates of embryo using treated spermatozoa with both liposome and circular DNA were higher than those using linear DNA. These findings raise the possibility thattreated spermatozoa with liposome/DNA complexes could be used in in vitro fertilization, and the exogenous DNA transferred into the oocytes. Taken together, we demonstrated that liposome a vector for the uptake of exogenous DNA in boar spermatozoa could improve the efficiency of sperm-mediated gene transfer in creating transgenic pig and the other domestic transgenic animals.
        4,000원
        534.
        2008.03 구독 인증기관 무료, 개인회원 유료
        Most studies on transgenic bioreactors have focused on expression levels of interest genes. In this study we examined whether transgenic bioreactors would inherit expression level of the Oansgene to long-term generations independently of transgene sources. We employed three transgenic mice, which were separately reported, carrying different transgenes and copy numbers, 27 kb of hLF and 22 kb of hIL-10 genomic sequences, and 1.3 kb of hTPO cDNA, respectively. Three females of the transgenic lineages crossbred with a wild-type male up to 20 generations to test transgenic frequencies of their progenies and to determine expression levels of the transgenes. Ultimately, transmission rates of kLF, hIL-10, and hTPO were 64.3+-7.0, 59.3+-9.8, and 56.1+-9.7, respectively, appeared following Mendelian pattern of inheritance. Notably, we found that levels of expressions of hLF, hIL-10, and hTPO in milk were sustained to high numbers of generations. No transgene silencing of expression was observed in every generations of all transgenic mice. In conclusion, we suggest that once established animal bioreactors could consistently transmit the transgene to continual generations, without loss of expressional activity, independently of transgene sources.
        4,000원
        536.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, commercially available pitch-based carbon fibers of general grade were post-heat-treated using a boxtype high temperature furnace at 1800℃, 2000˚, 2200℃, and 2400℃, respectively. The fundamental characteristics of each heat-treated carbon fibers were investigated in terms of chemical composition, morphology, thermal stability, X-ray diffraction, single filament tensile test, and electrical resistivity. The result showed that the fiber properties were significantly influenced by the post-heat-treatment, indicating the greater effect with increasing treatment temperature. The carbon contents, thermal stability, and tensile properties of the carbon fibers used here were further increased by the post-heat-treatment, whereas the d-spacing between graphene layers and the electrical resistivity were reduced with increasing post-heat-treatment temperature.
        4,000원
        538.
        2007.06 구독 인증기관 무료, 개인회원 유료
        Insulin-like growth factor II (IGF2) and H19 genes are mutually imprinted genes which may be responsible for abnormalities in the cloned fetuses and offspring. This study was performed to identify putative differentially methylated regions (DMRs) of porcine H19 locus and to explore its genomic imprinting in in vitro fertilized (IVF) and somatic cell nuclear transferred (SCNT) embryos. Based on mice genomic data, we identified DMRs on H19 and found porcine H19 DMRs that included three CTCF binding sites. Methylation patterns in IVF and SCNT embryos at the 2-, 4-, 8~16-cells and blastocyst stages were analyzed by BS (Bisulfite Sequencing)-PCR. The CpGs in CTCF1 was significantly unmethylated in the 2-cell stage IVF embryos. However, the 4- (29.1%) and 8~16-cell (68.2%) and blastocyst (48.2%) stages showed higher methylation levels (p<0.01). On the other hand, SCNT embryos were unmethylayted (0~2%) at all stages of development. The CpGs in CTCF2 showed almost unmethylation levels at the 2-, 4- and 8~16-cell and blastocyst stages of development in both IVF (0~14.1%) and SCNT (0~6.4%) embryos. At all stages of development, CTCF3 was unmethylated in IVF (0~17.3%) and SCNT (0~1.2%) embryos except at the blastocyst stage (54.5%) of IVF embryos. In conclusion, porcine SCNT embryos showed an aberrant methylation pattern comprised to IVF embryos. Therefore, we suggest that the aberrant methylation pattern of H19 loci may be a reason for increased abnormal fetus after embryo transfer of porcine SCNT embryos.
        4,000원