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        검색결과 70

        44.
        2003.12 구독 인증기관 무료, 개인회원 유료
        This study was performed to test the cellulose digestibility using the transgenic pigs harboring cellulose degradation gene D (CelD). After delivered offsprings between normal pig and transgenic swine, DNA was isolated from piglets tail for PCR analysis. In first generation, five out of 65 piglets showed CelD positive. Unfortunately, four CelD-positive pigs were died during growing, but one survived pig was used as a transgenic founder to produce F₁ descendents. Among 3 F₁ transgenic pigs produced, one died and the remaining two pigs were used to test the fiber digest efficiency. An assorted feed was composite of 5% fiber with other ingredients. The feed of 3 kg per day was provided to the pigs including transgenic founders and littermate controls. The manure quantity was measured daily for a month, and all manures were dried for three days to analysis nitrogen, phosphate and fiber concentrations. The fiber digestion efficiencies of the transgenic F₁ pigs showed approximately 10% higher than those of control pigs. Fiber digestion was not greatly improved in transgenic pigs as it had been expected approximately 30%. Nitrogen concentration of transgenic pig′s manure was slowly decreased compare to the control pigs. Because there were only two transgenic pigs tested, a large number of transgenic pigs may be necessary to obtain more reliable data. Breeding of animals to obtain sufficient transgenic pigs subjected for a further study is on progress. Taken together, this study demonstrated successful production of transgenic pigs with increase of cellulose digestibility in the porcine feed.
        4,000원
        45.
        2003.12 구독 인증기관 무료, 개인회원 유료
        The present study were performed to analysis the hematocrit and the red blood cells content into the blood plasma of the transgenic pigs harboring recombinent human erythropoietin gene (rhEPO). Mouse whey acidic protein (mWAP) linked to rhEPO gene was microinjected into pronuclei of porcine one-cell zygotes. After delivered of offspring, PCR analyses identified one mWAP-rhEPO transgenic founder offspring(F/sub 0/). The first generation of transgenic pig (F/sub 0/) harboring mWAP-hEPO appeared to be a male, and the second generation (F₁) pigs were made by natural mating of F/sub 0/ with domestic swine, and male and female transgenic pigs (F₁) were identified by PCR. The blood samples from transgenic and normal pigs were collected for 50 days during lactation and were counted the red blood cell (RBC) numbers and Hematocrit (HCT) content into the blood. The transgenic pigs expressing rhEPO in their blood gave rise to higher RBC numbers and HCT contents than control animals. rhEPO was secreted both in the blood and milk of genetically engineered pigs harboring rhEPO gene. Therefore, this study provides a model regarding the production of transgenic pig carrying hEPO transgene for biomedical research.
        4,000원
        46.
        2003.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to find out the changes on serum concentrations of estradiol-17β, progesterone in primiparous Duroc, Landrace and Yorkshire sows weaned at 7 or 21 days. Also, we compared the litter size at birth and weaning among the breeds weaned after lactation for 7 or 21 days. The estradiol-17β concentrations among the breeds were 6.9∼8.8 pg/ml and 6.4∼8.8 pg/ml after lactation for 7 or 21 days, respectively. The progesterone concentrations ranged from 0.3 ng/ml to 1.6 ng/ml. Duroc sow showed higher progesterone concentration compared with Landrace and Yorkshire sows weaned after lactation for 7 or 21 days. Also, we found out that litter size at birth and weaning, respectively, did not show any differences between day 7 and day 21 of lactation. From the facts mentioned above, it was suggested that very early weaning systems could work with no apparent adverse effect on prolificacy.
        4,000원
        48.
        2003.03 구독 인증기관 무료, 개인회원 유료
        본 연구는 xanthine(X)-xanthine oxidase(XO) system하에서 돼지 난자의 체외성숙과 체외수정에 대한 catalase의 영향을 검토하였다. 그 결과 돼지 난포난자가 X 또는 XO하에서 배양되었을 때, 난포난자의 성숙율은 다른 배양시간에도 불구하고 catalase 첨가 유무에 따른 유의적인 차이를 나타내지 않았다. 그렇지만, X-XO-catalase system하에서 배양한 경우 유의적으로 높은 성숙율을 얻었다(P<0.05). 퇴행난자의 비율은 배양기간이 늘어남에 따라 증가되었으며, 배양 120시간에서는 catalase 첨가시보다 무첨가시에 유의적으로 높았다. 다른 한편으로, 단위발생 난자들이 배양 72시간에 높은 비율로 관찰되었지만, 다양한 배양시간에서 catalase 첨가유무에 따른 차이는 발견되지 않았다. 또 다른 실험에서, 동결-응해된 돼지 정자가 체외수정을 위해 X-XO system으로 처리되었다. 난자투명대에 대한 정자침입율은 none (P<0.05), XO, X+XO하에서 체외수정시 catalase 무첨가시보다 첨가시에 높게 나타났다. 다른 한편으로, 돼지정자가 none, X, XO, X+XO로 처리되었을 때, lipid peroxidation은 catalase 첨가시보다 무첨가시에 높은 비율로 나타났으며, 그 결과 정자침입과 lipid peroxidation에서의 변화가 상반되는 양상을 보였다. 그렇지만, 모든 조건하에서 정자의 sulfhydry (-SH) group의 함량은 catalase 첨가시에 높게 측정되었다. 난자의 투명대에 대한 정자의 접착 정도는 salt-stored 돼지 난자에 대한 정자접착을 통해서 평가되었으며, control group의 경우 X, XO, X+XO group에 비해 높은 정자접착율이 관찰되었다. 그렇지만, catalase 첨가유무에 따른 유의적인 차이는 인정되지 않았다. 본 연구의 결과는 X-XO-catalase system에 대한 난포난자와 정자의 노출이 돼지에서의 체외성숙과 체외수정을 촉진시키는 것으로 생각된다.
        4,000원
        55.
        2000.06 구독 인증기관·개인회원 무료
        Non-stoichiometric ceramics of were prepared by self-propagating high temperature synthesis reaction with various processing conditions and their stoichometric numbers were determined by neutron diffraction. The neutron diffraction patterns were measured at room temperature using monochromatic neutrons with a wave length of 0.18339 nm from a Ge(331) mocochromator at a 90 degree take off angle. The Rietveld refinement of each pattern converged to good agreement (x2=1.88-2.24). The neutron diffraction analysis revealed the final stoichiometries of the ferrites were and respectively. This supports that final stoichiometric number of the self-propagating high temperature synthesis product can be controlled by the processing parameters during the combustion reaction.
        58.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In the present work we introduce a new flare activity indicator, MAD and examine its characteristics by analyzing a set of successive three days' observations of a typical active region, AR2372. The computed MAD is compared with conventional activity indicator such as separator. It is found that. (1) MAD traces very well the separator, (2) it. singles out. local discontinuity of magnetic field lines and (3) it. is a good measure of describing the evolutionary status of active region.
        59.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        긴덜이리응애와 dicofol 저항성 및 감수성 점박이응애에 대한 아바맥틴의 선택독성을 실험실 내에서 엽침지법으로 조사하였다. 아바멕틴은 긴털이리응애에 대해서는 독성이 낮은 반면, 점박이응애에 대해서는 살균효과가 높았다. 0.12 ppm과 0.6 ppm의 농도에서 점박이응애는 두 계통 모두 침지 후 48시간 0]내에 사망하였고, 0.06 ppm과 0.012 ppm의 낮은 농도에서 120시간 이후에는 77% 이상이 사망하였다. 그러나긴털이리응애의 암컷성충은 0.12ppm에서는 생존솔과 활동력이 영향을 받지 않았고, 0.6ppm과 6ppm의 높은 농도에서도 사망솔이 약 20~23%이었다. 아바맨틴은 산란후 l일 이내의 점박이응애의 난에 대해서는 패화솔에 영향을 미치지 않았으나 산란후 4일된 란에서는 패화솔이 멸소하였다. 반면에0.006-6ppm 용액에 긴털이리응애 난을 침지한경우 난의 패화솔과 그 난에서 부화한 약충의 발육에는 영향이 없었다. 긴털이리응애의 암컷 성충을 0.6 ppm과- 0.12ppm에 침지했을 때 산란수가 줄어들지 않았으나 잠박이응애의 산란수는0.006-0.6 ppm의 농도에서 현저히 감소하였다. 이상과 같이 아바맥틴은 점박이응애와 긴털이리응애에 대한 선택독성이 높은 약제로 점박이응애의 결합방제에 유용하게 이용될 수 있을 것으로 생각되며, 점박이응애에 대한 아치사농도(0.012-0.06 ppm)는 긴털이리응애와 점박이응애의 밀도를 조사하는데 이용될 수 있을 것으로 생각된다.
        4,000원
        60.
        2013.07 서비스 종료(열람 제한)
        We investigated whether sound could alter gene expression in plants. Using a sound-treated subtractive library, a set of sound-responsive genes in plants was demonstrated through mRNA expression analyses. Of them, the rbcS and ald genes, which are light responsive, up-regulated their expression with sound treatment in both light and in dark conditions. This suggested that sound could be used as a gene regulator instead of light. When we analyzed ald gene expression using various single wavelengths, a significant increase in mRNA levels was found at 125 or 250 Hz but decreased at 50 Hz, indicating that the gene responded to sound in a wavelength-specific manner. To determine whether the ald promoter respond to sound, we generated transgenic rice plants harboring the chimeric gene consisting of a 1,506-bp promoter fragment of the ald gene fused to Escherichia coli GUS reporter gene. Analyses of mRNA expressison level of three independent transgenic lines sound-treated with 50 or 250 Hz for 4 h showed that the Gus gene expression in all three transgenic lines was up regulated by 250 Hz, but down regulated by 50 Hz. These results correlated with sound responsive mRNA expression pattern observed for the ald gene in rice plants, indicating that the 1,506-bp ald promoter confers sound-responsiveness on a reporter gene in transgenic rice plants. We also investigated whether sound waves could improve salt tolerance in rice seedling. The rice seedlings were sound treated with 800 Hz for 1hr, and then treated with 0, 75, 150, and 225mM NaCl for 3 days to observe changes in physiological and morphological aspects. Sound treatment seedlings resulted in enhanced salt stress tolerance, mainly demonstrated by the sound treated seedlings exhibiting of increased root relative water contents (RWC), root length and weight, photochemical efficiency (ratio of variable to maximum fluorescence, Fv/Fm), and germination rate under salt stress condition. This demonstrates that a specific sound wave might be used, not only to alter gene expression in plant, but also to improve salt stress tolerance.
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