검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 1,256

        564.
        2012.10 구독 인증기관·개인회원 무료
        The baculovirus expression system is one of the most popular methods used for the production of recombinant proteins but has several complex steps which have proved inherently difficult to meet a multi-parellel process. We have developed a novel recombinant bacmid, bEasyBm that enabling easy and fast generation of pure recombinant virus without any purification step. In the bEasyBm, attR recombination sites were introduced to facilitate the generation of recombinant viral genome by in vitro transposition. Moreover, extracellular RNase gene from bacillus amyloliquefaciens, barnase, was expressed under the control of Cotesia plutellae bracovirus early promoter. Therefore, only when the barnase gene was replaced to gene of interest, the bEasyBm could replicate in host insect cells. When the bEasyBm was transposed with pDualBac-EGFP and pDualBac-LUC respectively, there were no non-recombinant backgrounds were detected from unpurified BmEasy-EGFP or BmEasy-LUC stocks. In addition, the resulting recombinant virus, BmEasy-EGFP, showed comparable level of EGFP expression efficiency with the plaque-purified recombinant virus, BmEGFP, which was constructed using bBmGOZA system. Based on these results, high-throughput condition for generation of multiple recombinant viruses in a time was established.
        565.
        2012.10 구독 인증기관·개인회원 무료
        Varieties of Bacillus thuringiensis (Bt) crystal proteins, Cry proteins, have so far been found as one of the most successful biological control agents which are safe to natural environments for a long time. Recently, 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. To construct novel cry genes with improved 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. In the further study, we plan to investigate their insecticidal activity against Plutella xylostella, S. exigua and O. furnacalis larvae.
        567.
        2012.08 구독 인증기관 무료, 개인회원 유료
        Environmental problem due to environmental pollution and CO2 emission has brought a strong attention on issues of sustainable urban development in urban planning area. Many urban planning researches have been argued that 'decentralized concentration' is one of the key issues for the sustainable urban spatial structure. Decentralized city is to create sustainable urban structure by realizing the supply system for urban energy efficiency through restriction of car use, proper urban density, and mixed-use. This study aims at exploring the concept of 'decentralized concentration' and comparing its characteristics of 'decentralized concentration' urban structure found in urban planning theories.
        4,000원
        568.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Meedon rice varieties are important for local adaptability, grain quality and market availability, and have been grown in Myanmar for centuries. Because of temporal variability and spatial heterogeneity, Meedon rice varieties in rainfed lowland areas may be diverse. However, information on diversity of Meedon rice germplasm is limited. This study was carried out to assess genetic diversity and to analyze population structure of Meedon rice germplasm conserved in Myanmar Seed Bank using SSR markers. For assessing genetic diversity, 154 accessions of Meedon rice germplasm were analyzed with nine SSR markers. A total of 86 alleles were detected with an average of 9.6 alleles per locus. All the loci were found to be polymorphic, and there were considerable genetic variation among accessions with mean values of expected heterozygosity (HE) = 0.5774 and polymorphic information content (PIC) = 0.5496. High frequency of rare alleles was identified, among which 35 unique (accession-specific) alleles were observed. Based on cluster analysis, rice accessions were mainly clustered into two groups, and as a result of model-based analysis, two distinct genetic populations and an admixture were classified. This result indicated that SSR markers have proved to be useful markers for detecting genetic diversity in Meedon rice, and the occurrence of a considerably high number of rare and unique alleles in the germplasm indicates their potentiality as a reservoir of rare genotypes for use. Unique alleles are also important because they may be diagnostic of a particular type of genotype for identification.
        4,000원
        569.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present an analysis of the papers published in the journals Nature and Science in the years from 2006 to 2010. During this period, 7788 papers in total were published in the two journals. This includes 544 astronomy papers that correspond to 7.0% of the papers in 'all' research fields and 18.9% of those in the field of 'physical sciences'. The sub-fields of research of the astronomy papers are distributed, in a descending order of the number of papers, in Solar System, stellar astronomy, galaxies and the universe, the Milky Way Galaxy, and exoplanets. The observational facilities used for the studies are mainly ground-based telescopes (31.1%), spacecrafts (27.0%), and space telescopes (22.8%), while 16.0% of papers did not use any noticeable facilities and 1.7% used other facilities. Korean scientists have published 86 papers (33 in Nature and 53 in Science), which is 1.10% of all the papers (N = 7788) in the two journals. The share of papers by Korean astronomers among the scientific papers by Koreans is 8.14%, slightly higher than the contribution of astronomy papers (7.0%) in both journals.
        4,300원
        571.
        2012.06 구독 인증기관·개인회원 무료
        The influenza viruses can be spread from birds to people. In this process, the pig is the intermediate host, and this virus is amplified and produces many mutations in pigs. Therefore, we attempted to develop the influenza-resistant pigs for the study of the virulence test and the transgenic (TG) animal model for translational research. At interferon- α, γ treated cells, the porcine Mx2 protein has been observed near the nuclear envelope and inhibits influenza virus proliferation, but not in common cells. So, we tried to produce the Mx2 gene over-expressed pig by somatic cell nuclear transfer(SCNT).First, we establish the Mx2 gene over expressed cells for the preparation of the TG donor cells. Porcine fetal fibroblasts were transfected with cytomegalo virus vector which include the porcine Mx2 gene. The established transgenic cell was injected into the enucleated ooplasm for the production of the Mx2-TG cloned embryos. Total, 511 female TG porcine SCNT embryos (TG-SCNTembryos) were made. The 511 female TG-SCNT embryos were transferred to five surrogates. On 25 days after embryo transfer, two of female embryos’ surrogates were diagnosed as pregnant (pregnancy rate, 40%). On day 114, we obtained six cloned piglets and four mummies from two of female embryos’ surrogate. Being analyzed by PCR, all female piglets were not integrated with Mx2 gene. Hereby, we again established newly male MX-TG cell line for donor cell of SCNT. 427 male TG-SCNT embryos were made. From these, 38 of male TG-SCNT embryos were cultured in in vitro to confirm the developmental capacity of TG-SCNT embryos. Among these porcine SCNT-TG embryos, 26 embryos (68.4%) were cleaved. Finally, 5 transgenic porcine SCNT embryos (13.2%) developed to the blastocyst stage. All male TGSCNT blastocysts were proved to be integrated with Mx2 gene as PCR analysis. Therefore, we expect that newly birth male piglets will be targeted with MX2 gene. The remaining 389 male embryos were transferred to four surrogates. On 25 days after embryo transfer, one of male embryos’ surrogates was diagnosed as pregnant (pregnancy rate, 25%). Now, pregnant surrogate have maintained at 88 days after embryo transfer and shown more than eight embryonic sacs. This study has presented new possibilities of production of influenza virus resistant pig by SCNT for translational research. * This work was supported by a grant from Next-Generation BioGreen 21 program (# PJ008121), Rural Development Administration, Republic of Korea.
        572.
        2012.06 구독 인증기관·개인회원 무료
        Among laboratory animals, pigs are anatomically and physiologically closer to human. Transgenic (TG) pigs can be widely applied as models of human diseases. Many researchers created TG pigs which have specific modified genome under a constitutively active promoter. A constitutively active promoter is effective to express a target gene, but the uncontrollable expression often results in unwanted outcomes. In this study, as a way to solve these problems, we tried to regulate the expression of target genes by tetracycline (Tet) on/off system. We tested the operation of Tet on/off system in TG donor cells. Miniature porcine fetal fibroblasts were transfected with universal doxycycline- inducible vector and an enhanced green fluorescent protein (eGFP) was used as the target gene. The induced transgene expression by doxycycline was detected on fluorescence microscopy. On one day after 1 μg/ml doxycycline treatment, the fluorescence intensity for TG cells was increased. And we then performed Somatic Cell Nuclear Transfer (SCNT) to confirm the working of Tet on/off system in the porcine SCNT-TG embryos. Total 649 transgenic porcine SCNT embryos were made. From these, 64 of SCNT embryos used in invitroculturewith1 μg/mldoxycycline. Among these porcine SCNT-TG embryos, 39 embryos (60.9%) were cleaved. Finally, 15 transgenic porcine SCNT embryos developed blastocyst. Induced transgene expression was observed all of cleaved embryos and blastocysts. The remaining 585 embryos were transferred to 6 surrogates. On 25 days after embryo transfer, two surrogates were diagnosed as pregnant (pregnancy rate =33.3%). On day 113 (one day prior to delivery), we obtained six cloned TG piglets from first pregnant surrogate. Unfortunately, all TG piglets died because their surrogate died suddenly at delivery time. However, we could obtain the TG cell lines from the cloned TG piglets. Being analyzed by PCR, all piglets were found to be eGFP gene targeted. Now, second pregnant surrogate have maintained at 80 days after embryo transfer and shown more than three embryonic sacs. This data suggested that, Tet on/off system can control target gene expression in transgenic porcine SCNT embryos. This result has presented new possibilities of regulation of target gene expression in cloned TG pigs by Tet on/off system. * This work was supported by a grant from Next-Generation BioGreen 21 program (# PJ008121), Rural Development Administration, Republic of Korea.
        573.
        2012.06 구독 인증기관·개인회원 무료
        Porcine blastocyst’s quality derived from in vitro is inferior to in vivo derived blastocysts. In this study, to improve in vitro derived blastocyst’s quality and then establish porcine ESCs (pESCs), we treated in vitro fertilized (IVF) embryos and parthenogenetic activated (PA) embryos with three chemicals: porcine granulocyte-macrophage colony stimulating factor (pGM-CSF), resveratrol (RES) and β-mercaptoethanol (β-ME). The control group was produced using M199 media in in vitro maturation (IVM) and porcine zygote medium-3 (PZM3) in in vitro culture (IVC). The treatment group is produced using M199 with 2 μM RES in IVM and PZM5 with 10 ng/mL pGM-CSF, 2 μM RES and 10 μM β-ME in IVC. Data were analyzed with SPSS 17.0 using Duncan’s multiple range test. In total, 1210 embryos in PA and 612 embryos in IVF evaluated. As results, we observed overall blastocyst quality was increased. The blastocyst formation rates were significantly higher (p<0.05) in the treatment groups (54.5%) compared to the control group (43.4%) in PA and hatched blastocysts rates in day 6 and 7 were also increased significantly. Total cell numbers of blastocyst were significantly higher (p<0.05) in the treatment group (55.1) compared to the control group (45.6). In IVF, hatched blastocysts rates in day 7 were increased significantly, too. After seeding porcine blastocyst, the attachment rates were higher in the treatment group (36.2% in IVF and 32.2% in PA) than the control group (26.6% in IVF and 19.5% in PA). Also, colonization rates and cell line derivation rates were higher in treatment group than control group. Colonization rates of control group were 10.8% in IVF and 2.4% in PA, but treatment group were 17.75% in IVF, and 13.1% in PA. And we investigated the correlation between state of blastocysts and attachment rate. The highest attachment rate is in hatched blastocyst (78.35±15.74 %). So, the novel system increased quality of porcine blastocysts produced from in vitro, subsequently increased attachment rates. The cell line derivation rates were 4.2% (IVF) and 2.4% (PA) in control group. In treatment group, they were 10.0% (IVF) and 7.2% (PA). We established 3 cell lines from PA blastocysts (1 cell line in control group and 2 cell lines in treatment group). All cell line has alkaline phosphatase activity and express pluri-potent markers. In conclusion, the novel system of IVM and IVC (the treatment of RES during IVM and RES, β-ME, and pGM-CSF during IVC) increased quality of porcine blastocysts produced from in vitro, subsequently increased derivation rates of porcine putative ESCs.
        574.
        2012.06 구독 인증기관·개인회원 무료
        The present study examined the expression of porcine sirtuin 1–3 (Sirt1–3) genes in immature (germinal vesicle; GV stage), mature (metaphase II; MII stage) oocytes, preimplantation embryos derived from parthenogenetic activation (PA), in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT). We also investigated the role of sirtuins in oocyte nuclear and cytoplasmic maturation, and embryonic development of PA and IVF embryos using sirtuin inhibitor [5 mM nicotinamide (NAM) and 100 μM sirtinol]. The expression of Sirt1–3 mRNA was significantly (p<0.05) up-regulated during IVM. The expression patterns of Sirt1–3 mRNA in preimplantation embryos of PA, IVF and SCNT were gradually (p<0.05) decreased from MII stage of oocyte to blastocyst stage. Especially, the expressions of Sirt1 and Sirt3 in SCNT blastocysts were significantly lower than IVF blastocysts. Treatment with nicotinamide (NAM) during IVM resulted in significantly decreased nuclear maturation but it was restored when NAM treated with 2 μM resveratrol (RES; known as antioxidant and sirtuin activator) compared to the control (control: 88.9%, NAM: 67.9% and NAM+RES: 86.4% respectively). Intracellular reactive oxygen species (ROS) level of oocytes matured with NAM was significantly increased and with NAM+RES was significantly decreased compared to the control. Treatment with sirtuin inhibitors during IVC resulted in significantly decreased blastocyst formation and total cell number of blastocyst derived from PA (NAM: 29.4% and 29.6, sirtinol: 31.0% and 30.3, and control: 40.9% and 41.7, respectively) and IVF embryos (NAM: 10.4% and 30.9, sirtinol: 6.3% and 30.5, and control: 16.7% and 42.8, respectively). There was no significant difference in cleavage rate both PA and IVF embryos. Oocytes treated with NAM during IVM showed significantly lower expression of PCNA, Bax, Bcl-2, POU5F1 and Sirt1–3 compared to the control. Oocytes treated with NAM+RES during IVM restored gene expression except POU5F1. Similarly, PA derived blastocysts treated with NAM during IVM showed down-regulation of PCNA, Bax, Bcl–2, POU5F1 and Sirt1–2. The blastocysts derived from PA embryos treated with sirtuin inhibitors during IVC showed lower (p<0.05) expressions of POU5F1 and Cdx2 genes. Also, Sirt2 mRNA expression was significantly decreased in sirtinol treated group and Sirt3 mRNA expression was also significantly de -creased in both NAM and sirtinol treated groups compared to the control. These findings indicate that Sirt1–3 which are transcribed and stored during oocyte maturation may have physiological and important roles in porcine oocyte maturation and preimplantation embryonic development by regulating gene expressions. * This work was supported by a grant from Next-Generation BioGreen 21 program (# PJ008121), Rural Development Administration, Republic of Korea.
        575.
        2012.06 구독 인증기관·개인회원 무료
        Neural stem cells (NSCs) are self-renewing tripotent cell populations and have capacity of neuronal (neurons) and glial (astrocytes and oligodendrocytes) differentiation. Many researchers have reported that NSCs have therapeutic effects in neurological disease by transplantation. However, it is not easy to obtain NSCs in vitro. Recently, Yamanaka and colleagues showed that somatic cells could be reprogrammed into pluripotent state by enforcing reprogramming factors. Induced pluripotent stem (iPS) cells undergo unlimited self-renewal and have differentiation potential into various types of cells like embryonic stem cells. Direct differentiation into a specialized cell types from iPS cells hold considerable promise for regenerative medicine as well as basic research. Here, we induced differentiation of iPS cells into NSCs in vitro and in vivo, which were compared with embryonic stem (ES) cell-derived NSCs and brain derived NSCs. NSCs from ES and iPS cells were morphologically indistinguishable from brain derived NSCs and stained positive for NSCs markers Nestin and Sox2. ES cells derived NSCs were transcriptionally distinguishable from brain derived NSCs. However, global gene expression pattern were similar but distinct between iPS derived NSCs and brain derived NSCs. Moreover, iPS derived NSCs were spontaneously aggregated upon passaging, formed ES cell like colonies, and finally reactivated Oct4-GFP. The spontaneously reverted GFP-positive cells (iPS-NSC-iPS) expressed similar levels of pluripotency markers (Oct4,Nanog) to ES and iPS cells, and could form germ line chimera. One possible explanation for this phenomenon is that spontaneously re-reprogramming was associated with transgene re-activation when iPS cells were differentiated into NSCs. However, NSCs from dox-inducible iPScells could not be reprogrammed into pluripotent state without doxycycline. Taken together, iPS derived NSCs were morphologically and similar to brain derived NSCs, but differ in gene expression pattern and maintenance. * This work was supported by the Next Generation Bio-Green21 Program funded by the Rural Development Administration (Grant PJ008009).
        576.
        2012.05 구독 인증기관·개인회원 무료
        Toxicities of 10 insecticides were examined against late third instars of Culex tritaeniorhynchus using the direct-contact mortality bioassay. Six geospatially distant field mosquitoes were collected from Chuncheon-si (designated CC-CT), Hwaseong (HS-CT), Seosan (SS-CT) Jeonju (JJ-CT), Daegu (DG-CT), and Busan (BS-CT) in the Republic of Korea (ROK). Marked regional variations of insecticide susceptibility were observed. Field populations of SS-CT, JJ-CT and DG-CT from agricultural areas showed higher to extremely higher insecticide susceptibility to pyrethroids than those of CC-CT, HS-CT and BS-CT strains from none agricultural areas. Extremely high to low levels of susceptibility were measured: bifenthrin, susceptible ratio (SR) = 2.7–896.3; β-cyfluthrin, SR = 1.8–633.3; α-cypermethrin, SR = 1.2–1,051.9; deltamethrin, SR = 1.3–711.1; permethrin, SR = 1.5–1,053.4 etofenprox, SR = 2.2–29.3; chlorfenapyr, SR = 5.1–103.6; chlorpyrifos, SR = 2.3–337.0; fenitrothion, SR = 2.0–142.3 and fenthion, SR = 1.4–186.2. Culex tritaeniorhynchus populations from rice paddies had been under heavy selection pressure due to the agricultural insecticides and that’s why the mosquito species demonstrated high resistance to pyrethroids which were used for a long time to control agricultural pests in the localities. These results indicate that careful selection and rotational use of these insecticides mayresult in continued satisfactory control against field populations of Japanese encephalitis vector mosquitoes.
        577.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study effectiveness of core strengthening exercise programs on symmetric double limb support and balance ability for elderly. The subjects that 30 persons between the ages of 65~80 elderly participated were divided into two groups randomly for 8 weeks. Tetrax interactive balance system and Berg's balance scale were used to assess support and stability. Paired t-tests were used to evaluate the changes before and after intervention. The difference between the groups was compared using an independent t-test. The experimental group showed significantly increase weight support, stability, balance(p<.05). However, the control group not showed significantly increase weight support, stability, balance(p>.05). In a variation, experimental and control groups showed significantly increased rate of weight support, stability, balance(p<.05). Consequently, core strengthening exercise program should be considered as a therapeutic method for the elderly to improve the balance ability and effectiveness on falls.
        4,000원
        578.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to identify how a self-stretching exercise program affects pain for each body area, pain relief and job satisfaction for care workers. 20 of 40 care workers with musculoskeletal symptom were randomly selected and participated a self-stretching exercise program consisting of 15 motions. The intervention was done five times or more per weeks for 8 weeks and 1 session lasted within 15 minutes. 'Musculoskeletal symptom survey table' of the Korea Occupational Safety and Health Agency(KOSHA) and JDI(Job Descriptive Index) was used for pain on the musculoskeletal symptom and job satisfaction. Survey were done twice before and after the program. The result of this study showed that self-stretching exercise program group(SSPG) relieved from pain significantly in the shoulders(p<.01) and lumbar(p<.05), comparing to the non selfstretching exercise program group(NSPG). Although no significant difference on variations in the JDI appeared in SSPG, the significant reduction appeared from the colleague relationship and organization in NSPG(p<.05). SSPG showed the significant increase on variations in JDI from the job and organization comparing to NSPG. Especially, the improvement on satisfaction for the organization was shown(p<.05). Accordingly, the self-stretching exercise program for care workers can be said to positively affect the overall pain relief and increase on the JDI.
        4,000원
        579.
        2012.03 구독 인증기관 무료, 개인회원 유료
        For reconstituting genetic resource(Korean Native Chicken: KNC) with grem-line chimeric chicken made with cryopreserved biastdermal cells, the experiments were carried out to optimize cryopreservating conditions. Stage X biastdemal cells were collected from KNC embryos and dissociated. Cells were susupended in medium containing cyopretectant and fetal bovine serum(FBS), and distributed into plastic ampules. Cell susupensions were seeded to induce ice formation at —7 ℃ to —35 ℃ at in the experiments, the effect of modification of dissociation way, concentration of FBS and cell density on the vaibility of frezen-thawed cells were investigated by trypan blue exclusion. Then change the way of cell dissociation from pipetting to short time vortexing, viability of frozen-thawed cell tended to be increaced from 29 % to 52 %. Increase concentraition of FBS in frozen medium from 20 % to 80 % made viability of thawed cell from 28 % to 35 %. The viability of thawed cells were 33.9% frozen at 2 embryos/ 0.5ml, and 43.6 % frozen at 20 embryos/0.5 ml. Furthermore, combination of three modifications make big improvement. The viability of frozen-thawed cell was 60 % for combinated method, and 41 % for general method. This result means the advance to practical cryoreservation of blastdermal cell of the KNC(Ogolgye breed).
        4,000원
        580.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        꼬마배나무이 (Cacopsylla pyricola)에 저항성 품종육성을 위한 육종재료를 선발코자 월동형 성충수, 단과지내의 산란수, 과총엽내의약충수 및 수관 전체적인 그을음 발생정도를 15개 종 및 종간잡종133개 유전자원을 대상으로 조사하였다. 월동형 성충수는 Pyrus.calleryana 4.6마리, 단과지내 산란수는 P. calleryana 0.3개, 과총엽내약충수는 P. calleryana 0마리, 그리고 그을음 발생정도는 P.betulaefolia, P. calleryana, P. communis, P. hybrid (P.pyrifolia × P.communis), P. lindleyi 0으로 발생 및 피해정도가 가장 낮았으며 종간의 차이가 뚜렷하였다. 전체적으로 대목으로 이용하고 있는 콩배인P. calleryana와 P. betulaefolia가 조사 대상 유전자원 중 가장 높은 항객성(antixenosis)을 보였으나 품질개량에 많은 기간이 요구됨에 따라 실용적으로는 서양배(P. communis) 중 ‘Conference', 'Cascade','Bosc', 'Winter Nelis' 가 가장 낮은 발생 및 피해정도를 보여 꼬마배나무이 저항성 품종 육성을 위한 좋은 육종재료로 판단되었다.
        4,000원