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        검색결과 1,964

        1344.
        2011.10 구독 인증기관·개인회원 무료
        Despite of the presence of estradiol-17β (E2) in ovarian follicles, its role(s) in in vitro maturation (IVM) is still largely unknown, especially in pigs. Thus, the current study was conducted to investigate the effect of E2 on in vitro maturation (IVM) of porcine oocytes and subsequent preimplantation development using in vitro fertilization (IVF)- or somatic cell nuclear transfer (SCNT)-derived embryos. To define the effects of E2 on IVM and early embryogenesis, porcine oocytes were matured in the presence or absence of E2, fertilized in vitro and cultivated to blastocyst stage. Compared to control group, the production of MII oocytes was significantly increased by treatment with E2, accompanying with the increase in MPF content and ERK phosphorylation, and monospermic fertilization and blastocyst development rates were also greatly elevated in the E2-treated oocytes. In addition, the advantageous role of E2 was also found in blastomere survival, which was further evidenced by both elevation of anti-apoptotic transcript Bcl-XL and decrease of pro-apoptotic transcript Bax. Furthremore, these positive effects of E2 were highly reproducible in early development of SCNT embryos. Collectively, the current study strongly suggests that E2 can be used as a efficient IVM supplement leading to successful nuclear/cytoplasmic maturatioin in pigs.
        1345.
        2011.10 구독 인증기관·개인회원 무료
        Successful early embryogenesis of somatic cell nuclear transfer (SCNT) embryos is very important to produce cloned animals. However, poor preimplantation development of SCNT embryos has been a major obstacle to the generation of cloned animals due to a lack of understanding of developmental events and underlying mechanism(s). In the current study, we show that production of SCNT embryos with high developmental competence is dependent on the fusion method. Electrofusion causes spontaneous egg activation, accompanied by an increase in intracellular Ca2+ and improper nuclear remodeling, whereas Sendai virus (SV)-mediated fusion greatly reduces these events. In addition, SV-SCNT increased the blastocyst development rate and trophectoderm cell number compared to electrofusion-mediated SCNT (E-SCNT). In particular, expression of ER stress-associated genes and blastomere apoptosis were significantly increased in E-SCNT embryos, which could be alleviated by inhibition of ER stress or by using the SV-mediated fusion method. Taken together, these results strongly suggest that SV is a useful fusion material for improvement of preimplantation development of SCNT embryos through reduction of ER stress-associated apoptosis.
        1346.
        2011.10 구독 인증기관·개인회원 무료
        Plasmids from Bacillus thuringiensis have been implicated in pathogenicity as they carry the genes responsible for different types of diseases that in mammals and insects. A novel serogroup (H3a3b3d), B. thuringiensis strain K4 which showed mosquitocidal activity against Anopheles sinensis and Culex pipiens pallens, was isolated from fallen leaves in Mungyeong city, Republic of Korea. In contrast to the complicated plasmid profiles of B. thuringiensis H3 serotype strains, the strain K4 (designated as serovar mogi) had only one large plasmid (>200kb) on which the toxin genes were occasionally located. A 454 pyrosequencing was used for the complete sequencing of the large plasmid. The sequence analysis showed that k4 plasmid had at least seven putative cry genes, ending up to showing 84%, 75%, 73%, 58%, 84%, 39% and 75% homology with Cry27Aa, Cry19Ba, Cry20-like, Cry56Aa, Cry39ORF2, Cry8Ba and Cry40ORF2 toxins in amino acids, respectively. This novel 3a3b3d type strain, B. thuringiensis serovar mogi, can be used as a good resource for studying unknown mosquitocidal cry genes. The E. coli-B. thuringiensis shuttle vector, pHT1K was used to clone these cry genes for characterization. In each clone, the level of transcription and production of crystal proteins will be investigated in near the future.
        1347.
        2011.10 구독 인증기관·개인회원 무료
        Bacillus thuringiensis (Bt) is characterized by its ability to synthesize crystal toxins and also able to produce bacteriocins such as thuricin, tochicin, entomocin and bacthuricin. The present work, for the first time, describes the biological activity of bacteriocins from B. thuringiensis subsp. cameroun (Btc). Supernatant which was produced from a liquid culture of Btc had antimicrobial activity against various Bt subspecies, ending up to making a inhibition zone on an agar medium. A significant reduction in antimicrobial activity was observed when the supernatant was exposed to heat at 47~50°C for 15 min. Proteins were separated from the supernatant by a fast protein liquid chromatography (FPLC) given the thermal instability. A group of FPLC fractions had antimicrobial activity against Bt subsp. palmanyolensis, israelensis, 1-3, morrisoni, toguchini and kurstaki and a Bacillus. cereus ATCC21768, ATCC14579 and NRRLB-569. Interestingly, when the supernatant was individually incorporated into the liquid cultures of Bt subsp. israelensis (Bti) and mogi (Btm) with mosquitocidal activity, a vegetative cell growth was observed only in the Btm culture 10 h post-incubation. A possible recovery of vegetative Btm cell growth was observed, compared to a control without the supernatant. These results suggest that Btc produced proteinous antimicrobial substances, one of which may be used as a selection marker to separate Btm after possibly conjugating the two mosquitocidal strains.
        1348.
        2011.10 구독 인증기관·개인회원 무료
        Among 154 putative ORFs of Autographa californica multiple nucleopolyhedrovirus (AcMNPV), ac78 and ac79 are highly conserved genes in baculovirus, but their functions in the virus life cycle have been unknown so far. To determine their roles in AcMNPV replication, knockout mutants, ac78KO and ac79KO, were constructed using the plasmid capture system (PCS). Real-Time PCR analysis showed that both of ac78 and ac79 transcripts were first detected at 6 hours post-infection, and accumulated to maximum at 24 hours post-infection, suggesting that both of ac78 and ac79 are belong to late gene. When the genomic DNA of ac78KO was transfected into Sf9 cells, viral replication was restricted to a single cell infection. These results demonstrated that the ac78 play an important role in BV production, and therefore is essential for AcMNPV to mount a successful infection. Whereas Sf9 cells infected with the ac79KO showed normal viral symptoms such as rounding and swelling, OBs were not observed from majority of infected cells. These results suggested that the ac79 might play an important role in OB production.
        1349.
        2011.10 구독 인증기관·개인회원 무료
        톱다리개미허리노린재의 집합페로몬은 수컷에 의해 분비되며 같은 종의 성충과 약충을 유인하는 것으로 알려져 있다. 현재 합성된 집합페로몬을 이용한 유인트랩이 널리 이용되고 있다. 본 연구에서는 합성된 집합페르몬에 대한 톱다리개미허리노린재 성충과 약충의 반응을 먹이 섭식 조건을 달리하여 Y자 후각계(Y-tube olfactometer)를 이용하여 조사하였다. Y자 후각계 끝의 공기와 페로몬이 혼합되는 지점에서 교미경험이 없고 수분만 공급받은 성충의 최초 반응률은 수컷에서 84%, 암컷에서 90%이었다. 그리고 반응한 암컷과 수컷의 69%가 Y자 후각계의 집합페로몬 쪽으로 이동하였다. 제2령 약충에서는 수분과 설탕물을 공급받은 경우 최초 반응률은 각각 60과 56%이었고 그 중 각각 63과 64%가 집합페로몬 쪽을 선택하였다. 다만 콩을 먹이로 충분히 공급받은 제2령 약충은 최초 반응률이 34%로 낮았고 집합페로몬 쪽으로 유인된 비율도 31%로 낮았다. 따라서 톱다리개미허리노린재 약충이 먹이를 섭식한 후에는 집합페로몬에 적게 유인되는 것을 알 수 있다.
        1350.
        2011.10 구독 인증기관·개인회원 무료
        Periodical release of non-viable refrigerated eggs of Riptortus pedestris (Fabricius) has been found to enhance field parasitism level in soybean fields. However, optimum refrigeration conditions required for the eggs in order to preserve its quality to ensure effective level of parasitism for a longer period has been rarely reported. We assessed optimum environment condition for refrigeration of the eggs using three different temperatures (2, 6, and 10℃) and relative humidities (RH) (high, medium and low). Eggs of R. pedestris were refrigerated at nine combinations of temperature and relative humidity for 30 consecutive days. Those eggs were taken out and after 8 days, mated female Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) were individually exposed to the eggs, and their development, emergence, and sex ratio were examined. Number of eggs parasitized was highest (5.9) on eggs stored at 6℃ and high RH. Significantly higher male proportion was recorded in the eggs stored at 10℃. However, RH had no effect on the sex ratio. For both male and female, development time was the least on host eggs stored at 2℃ and high RH. Adult emergence was recorded highest from the eggs stored at 2℃ followed by 6℃ and at high RH. In conclusion, eggs refrigerated below 6℃ at high RH condition maintained better quality of R. pedestris eggs for the parasitization by O. nezarae.
        1351.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid, Myzus persicae (Sulzer), is one of the most important insect pests in the world. We have explored the possibility of using sounds as a stressor to control this species. Five sine wave frequencies (100, 500, 1000, 5000, 10000 Hz) with combination of three intensity (66, 78, 90 dB) were used as acoustic stimuli in the playback experiments. For behavioral bioassay, we examined frequencies of honeydew production (HDP) and wagging behavior, and duration of moving behavior. The HDP occurs regularly during each stage of nymphal or mature period, and rate of the HDP indicates a degree of food consumption. Aphids conduct wagging to determine a host plant or to find a feeding site. The moving behavior may be regarded as dispersal. As results, all acoustic stimuli significantly reduced rate of the HDP and increased rate of the moving behavior. There was a significant effect to induce the moving behavior in the test of 5000 Hz. In addition, the acoustic stimuli using 5000 Hz were the most effective to disturb feeding behavior of M. persicae at an individual level.
        1352.
        2011.10 구독 인증기관·개인회원 무료
        Aphids feed on host plants by penetrating the stems or leaves with stylets. The feeding behavior of aphids consists of probing, penetration, salivation, and sap ingestion. To assess the effects of sound on feeding behavior, we monitored the stylet activity of the green peach aphid, Myzus persicae (Sulzer), using electrical penetration graph (EPG). The use of EPG was critical for determining the stage, frequency, and duration of feeding in aphids. We played back four acoustic stimuli of sine waves with frequencies of 100, 500, 1000, and 5000 Hz to adult aphids. When the sound was treated, the frequencies of probing, penetration, and salivation increased, whereas the duration of sap ingestion decreased. The 100 Hz and 500 Hz was significantly effective to disturb ingestion of phloem sap. The results of EPG revealed that the acoustic stimuli may restrict aphid feeding by disturbing sap ingestion.
        1353.
        2011.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To perform imaging observations of optically red objects such as high redshift quasars and brown dwarfs, the Center for the Exploration of the Origin of the Universe (CEOU) recently developed an optical CCD camera, Camera for QUasars in EArly uNiverse (CQUEAN), which is sensitive at 0.7-1.1 μm. To enable observations with long exposures, we develop an auto-guiding system for CQUEAN. This system consists of an off-axis mirror, a baffle, a CCD camera, a motor and a differential decelerator. To increase the number of available guiding stars, we design a rotating mechanism for the off-axis guiding camera. The guiding field can be scanned along the 10 arcmin ring offset from the optical axis of the telescope. Combined with the auto-guiding software of the McDonald Observatory, we confirm that a stable image can be obtained with an exposure time as long as 1200 seconds.
        4,000원
        1354.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: International Association of Contact Lens Educators(IACLE)가 실시하는 STE결과를 분석하여 한국에서의 콘택트렌즈 교육 실태를 알아보고자 한다. 방법: 2010년 IACLE에서 주관한 STE에 참여한 12개 대학 안경광학과 학생들의 시험성적을 분석하여 대학 및 국가간 비교를 실시하였다. 결과: 12개 대학의 평균은 100점 만점을 기준으로 하여 54.01점이었으며 평균 합격률은 62.75%였다. 문항을 주제별로 7개 부류로 나누어 분석한 결과 평균 점수는 각각 전안부 해부 및 생리 48.73점, 콘택트렌즈 디자인 및 관리 46.14점, 콘택트렌즈 피팅원리 49.08점, 환자 검사 및 콘택트렌즈 처방 73.37점, 콘택트렌즈 관리 및 유지 66.12점, 콘택트렌즈에 대한 안구 반응 55.45점, 콘택트렌즈 착용으로 인한 부작용 52.54점으로 나타났다. 교육기간에 따라 2,3년제 대학과 4년제 대학을 비교해 본 결과 2,3년제 대학의 평균 점수가 53.35점, 4년제 대학의 점수가 54.94점으로 큰 차이를 보이지 않았다. 국가간 비교에서는 중국, 인도, 프랑스, 독일에 비해 한국 학생들의 점수가 다소 낮은 것으로 확인 되었다. 결론: 평균점수와 합격률에 있어 학교 및 과목 사이에 편차가 확인 되었다.
        4,000원
        1355.
        2011.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The photometric light curves of the W-type W UMa eclipsing contact binary system BB Pegasi have been found to be extremely asymmetric over all the observed 63 years in all wavelengths UBVR. The light curves have been characterized by occultation primary minima. Hence, the morphology of these light curves has been studied in view of these different asymmetric degrees. The system shows a distinct O'Connell effect, as well as depth variation. A 22.96 years of stellar dark spots cycle has been determined for the system. Almost the same cycle (22.78 yr) has been found for the depth variation of MinI and MinII. We also present an analysis of mid-eclipse time measurements of BB Peg. The analysis indicates a period decrement of 5.62X 10-8 day/yr, which can be interpreted in terms of mass transfer at a rate of -4.38 X 10-8M⊙/yr, from the more to the less massive component. The O - C diagram shows a damping sine wave covering two different cycles of 17.0 yr and 12.87 yr with amplitudes equal to 0.0071 and 0.0013 day, respectively. These unequal durations show a non-periodicity which may be explained as a result of magnetic activity cycling variations due to star spots. The obtained characteristics are consistent with similar chromospherically active stars, when applying the Applegate's (1992) mechanism.
        4,300원
        1356.
        2011.06 구독 인증기관 무료, 개인회원 유료
        Peripheral nerve injuries are very common in clinics and often result in severe functional deficits. The aim of this study was to evaluate the effect of treadmill running and electro-acupuncture on nerve regeneration and functional recovery of muscle activity following sciatic nerve crush injury in a rat model. A comparative study was conducted over 30 days on 60 adult male Sprague-Dawley rats grouped into sham control (C), electro-acupuncture (EA), treadmill (T), and treadmill plus electro-acupuncture (TEA). The left sciatic nerve was crushed for 30 sec using a hemostatic forceps and functional activity was evaluated with sciatic functional tests, nerve conduct velocity, muscle weight, and histology at 10, 20, and 30 days after injury. Muscle weight was significantly (P<0.05) increased between days 10 and 30 in the TEA group. In histology, the degree of damage was scored as C > TEA > T > EA, although necrosis and fibrosis of muscle was observed only in the TEA group. The EA and TEA groups showed rapid recovery with better myelinated axons on day 10. These results suggest that application of the TEA method with balanced exercise is a useful treatment option for peripheral nerve injury regeneration and muscle activity.
        4,000원
        1357.
        2011.06 구독 인증기관 무료, 개인회원 유료
        Chinese university internationalization is confronted with opportunities and challenges in the aftermath of the 2008 Financial Crisis. This study discusses the opportunities faced by China’s university internationalization after the 2008 Financial Crisis, such as the opportunities to attract more international students, increase student and faculty exchanges, redesign curriculums, and encourage cooperation between Chinese universities and top foreign universities. This study analyzes some of the challenges of Chinese universities such as how to enroll more international students and recruit more top-level global talent.
        4,000원
        1358.
        2011.05 구독 인증기관·개인회원 무료
        Porcine Circovirus Type2 (PCV2), a single-stranded DNA virus associated with Postweaning multisystemic wasting syndrome(PMWS) of swine, has two major open reading frames, ORF1 and ORF2. The genomic size and molecular weight of ORF2 is respectively 699bp, 28kDa. ORF2 encodes the capsid protein (structural protein) that has type-specific epitopes and is very immunogenic and associated with the induction of neutralizing antibodies, suggesting its potential use in diagnostic assays as well as vaccine development. For efficient production of the capsid proteins, we expressed the PCV2 ORF2 gene with baculovirus in the insect cells. In this study, PCV2 ORF2 was appropriately ligated into the baculovirus transfer vector, pBacPAK9 and pB9-Acpol19-110-EK. Sf21 cells were transfected with a mixture of the purified recombinant transfer vector and bAcGOZA. We generated and purified recombinant viruses containing PCV2 ORF2, and named rAc-B9-PCV2ORF2 and rAc-B9-19-110-EK-PCV2ORF2, respectively. Expression levels of capsid fusion proteins with a partial polyhedrin region of AcNPV more increased than recombinant proteins from non-fusion expressed. Also, expression efficiency increased over time and differed at MOI. As a results, fusion expression of porcine circovirus type2 ORF2 using baculovirus could be utilized as an alternative expression method to produce recombinant antigen against PCV2 infection and is worthy of further investigation.
        1359.
        2011.05 구독 인증기관·개인회원 무료
        Aujeszky's disease (AD), also called pseudorabies, is an infectious viral disease caused by an alpha herpes virus and has domestic and wild pigs, as well as a wide range of domestic and wild animals, as the natural host. Aujeszky's disease virus (ADV) virions contain several envelope glycoproteins. Among them, glycoproteins gB, gC and gD are regarded as the major immunogenicity proteins and the antibodies induced by them can neutralize virus in vitro or in vivo. In this study, we investigated expression of these glycoproteins using the bacterial and baculovirus expressionn system. Successful expression of ADV glycoproteins in E. coli was confirmed by SDS-PAGE and Western blot analysis and their optimal expression condition was determined. However, the recombinant proteins generated in the bacterial expression system which lacks glycosylation process frequently lose their biological activity. We tried to express the ADV glycoproteins using the baculovirus expression vector system. The recombinant gB, gC and gD were detected at approximately 100, 60 and 50 kDa on SDS-PAGE and Western blotting, respectively. The optimal expression conditions were determined for MOI(multiplicity of infection) and post-infection days. One MOI and 4 or 5 days post-infection were the best conditions for the expression of the ADV glycoproteins in Sf21 cells. We are currently investigating the antigenicity of recombinant proteins using experimental animals.
        1360.
        2011.05 구독 인증기관·개인회원 무료
        Bacillus thuringiensis (Bt) is characterized by its ability to synthesize crystal toxins and also able to produce bacteriocins such as thuricin, tochicin, entomocin and bacthuricin. The present work, for the first time, describes the biological activity of bacteriocins from B. thuringiensis subsp. cameroun (Btc). Supernatant which was produced from a liquid culture of Btc had antimicrobial activity against Bacillus cereus, ending up to making a inhibition zone on an agar medium. A significant reduction in antimicrobial activity was observed when the supernatant was exposed to heat at 75~100°C for 15 min. Proteins were separated from the supernatant by a fast protein liquid chromatography (FPLC) given the thermal instability. A group of FPLC fractions had antimicrobial activity against Bt subsp. palmanyolensis, israelensis, 1-3, morrisoni, toguchini and kurstaki, and B. cereus ACTC21768, ATCC14579 and NRRLB-569. Interestingly, when the supernatant was individually incorporated into the liquid cultures of Bt subsp. israelensis (Bti) and mogi (Btm) with mosquitocidal activity, a vegetative cell growth was observed only in the Btm culture 10 h post-incubation. A possible recovery of vegetative Btm cell growth was observed, compared to a control without the supernatant. These results suggest that Btc produced proteinous antimicrobial substances, one of which may be used as a selection marker to separate Btm after possibly conjugating the two mosquitocidal strains.