국내 핵의학은 1959년에 갑상선 질환 환자에서 131I를 이용하여 섭취 및 배출을 측정하면서 시작된 이후, 지난 60여 년간 괄목할 만한 발전을 이루어 왔다. 1961년에 도입된 핵의학 진단영상 검사는 감마카메라를 이용한 감마카메라영상 및 양전자단층 촬영(positron emission tomography, PET)을 이용한 PET/computed tomography (CT)가 현재 주요 검사로 자리잡고 있다. 감마 카메라와 PET/CT에 활용되는 방사성동위원소는 발생기 (generator)와 사이클로트론(cyclotron)을 통해 생산되며, 이러한 방사성동위원소는 표적 장기에 선택적으로 섭취되는 화합물에 표지되어 방사성의약품으로 조제된다. 국내에서 췌장담도 질환 환자에 주로 사용되는 핵의학 진단영상검사용 방사성의약품으 로는 전신뼈스캔에 사용되는 99mTc-dicarboxypropane diphosphonate (DPD)와 99mTc-methylene diphosphonate (MDP), 99mTc-hydroxymethylene diphosphonate (HMDP)가 있으며, 간담도스캔에는 99mTc-bromotriethyliminodiacetic acid (BrIDA 또는 mebrofenin)가 있다. 또한 18F-fluorodeoxyglucose (18F-FDG)와 18F-2-fluoro-3,4-dihydroxyphenylalanine (18F-FDOPA), 111Inpentetreotide (octreotide), 68Ga-1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid0-Tyr3-octreotide (DOTA-TOC)는 주로 췌장담도계 종양의 진단과 치료 방침 결정에 유용하게 활용 되고 있다. 핵의학 진단영상검사로 인한 환자의 의료 피폭은 국내 자연 방사선으로 의한 방사선량과 비교하여 수용 가능한 수준으로 여겨진다. 임상의가 핵의학 진단영상검사의 특성을 충분히 이해하고 이를 환자와 효과적으로 소통할 경우, 신뢰 관계 형성은 물론 진료의 질 향상에도 크게 기여할 수 있을 것이다.

Climate change has led to a significant increase in jellyfish populations globally, causing various problems. For power plants that use nearby seawater for cooling, the intrusion of jellyfish into intake systems can block the flow, leading to reduced output or even shutdowns. This issue is compounded by other small marine organisms like shrimp and salps, making it urgent to develop solutions to prevent their intrusion. This study addressed the problem using the BioSonics DT-X 120 kHz scientific fish finder to conduct preliminary tank experiments. We also deployed underwater acoustic and camera buoys around the intake of nuclear power plant, utilizing a bidirectional communication system between sea and land to collect data. Data collection took place from July 31, 2023 to August 1, 2023. While harmful organisms such as jellyfish and salps were not detected, we successfully gathered acoustic data on small fish measuring backscattering strength (SV). Analysis showed that fish schools were more prominent in the evening than during the day. The highest fish distribution was observed at 3:30 AM on July 31 with an SV of -44.8 dB while the lowest was at 12:30 PM on the same day with an SV of –63.4 dB. Additionally, a solar-powered system was used to enable real-time data acquisition from sea buoys with smooth communication between the land server and the offshore buoy located 1.8 km away. This research developed an acoustic-based monitoring system for detecting harmful organisms around the intake and provided foundational data for preventing marine organism intrusion and planning effective measures.

본 연구의 목적은 북한의 전술핵무기 개발 경과와 한국에 미치는 함의를 규명하는 것이다. 북한은 2021년 1월 8차 당대회를 통해 핵능력 고도화와 전술핵무기 개발을 공표하였다. 그리고 지속적으로 핵능력과 투발수단을 발전시키고 있다. 핵능력에서 가장 기본적이고 중요한 것은 무기급 플루토늄(WGPu)과 고농축우라늄(HEU), 삼중수소 등 핵물질과 다양한 투발수단이다. 북한은 원자로 가동 후 재처리를 통해 획득할 수 있는 WGPu보다는 은밀한 지하시설에서 농축이 가능한 HEU 위주로 핵물질을 증산하고 있고, 삼중수소의 생산을 위해 영변 핵시설을 이용 할 수 밖에 없을 것으로 판단된다. 그리고 투발수단의 능력향상을 위해 KN-23, KN-24, KN-25와 이동식발사대(TEL), 열차이동발사 등 다양 한 투발수단의 실험을 지속하면서 전술핵무기능력을 고도화하고 있다. 북한의 핵개발 단계는 사실상의 핵보유국을 넘어서 실제 핵을 운용할 수 있는 핵전력 작전운용과 현대화 단계로 진입한 것으로 판단된다. 북한은 이를 통해 공세적 핵태세를 추구하고, 고강도 국지도발 감행 등 현상변경을 위한 강압으로 확증보복전략뿐만 아니라 한반도에서 적극적 전쟁수행전략을 구사할 것으로 예상된다. 이에 대한 새로운 대응전략이 요구되고 있다.

본 연구의 목적은 미국의 확장억제 실행력과 신뢰성 제고를 위한 미국의 저위력 핵무기 개발 및 함의를 규명하는 것이다. 사실상의 핵보유국으로 부상한 북한의 핵위협에 대한 실질적인 대책마련이 시급하다. 이에 북한의 핵능력이 지속적으로 고도화되는 상황에서 한국의 북핵 대응전략은 북핵 위협 억제‧대응을 위한 ‘핵‧WMD 대응체계’ 구축을 위한 핵심전력을 조기에 확보하기 위해 노력하고 있다. 하지만 재래식 전력으로 북핵을 대응하는 것에도 한계가 있고, 핵금기에 따른 확장억제의 신뢰성도 의심받고 있는 실정이다. 이러한 미국의 확장억제 실행력과 신뢰성 제고 측면에서 미국이 개발하고 있는 저위력 핵무기 개발과 함의를 규명하고, 한국의 억제‧대응능력 강화를 위한 방안을 적극적으로 모색할 필요가 있다. 이를 위해 한‧미는 맞춤형 억제전략 발전과 미국의 확장억제 공약의 실행력을 제고해야 한다. 한‧미 연합 억제‧대응 능력을 강화하기 위해 나토의 핵공유와 같이 핵동맹으로 격상시키고, 확장억제전략협의체(EDSCG)보다 긴밀한 고위급 핵계획그룹(NPG) 발전 등이 있어야 할 것이다.

The osmolarity of a medium that is commonly used for in vitro culture (IVC) of oocytes and embryos is lower than that of oviductal fluid in pigs. In vivo oocytes and embryos can resist high osmolarities to some extent due to the presence of organic osmolytes such as glycine and alanine. These amino acids act as a protective shield to maintain the shape and viability in high osmotic environments. The aim of this study was to determine the effects of glycine or/and alanine in medium with two different osmolarities (280 and 320 mOsm) during IVC on embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. To this end, IVC was divided into two stages; the 0-2 and 3-7 days of IVC. In each stage, embryos were cultured in medium with 280, 320, or 360 mOsm and their combinations with or without glycine or/and alanine according to the experimental design. Treatment groups were termed as, for example, "T(osmolarity of a medium used in 0-2 days of IVC)-(osmolarity of a medium used in 3-7 days of IVC)" T280-280 was served as control. When PA embryos were cultured in medium with various osmolarities, T320-280 showed a significantly higher blastocyst formation (29.0%) than control (22.2%) and T360-360 groups (6.9%). Glycine treatment in T320-280 significantly increased blastocyst formation (50.4%) compared to T320-280 only (36.5%) while no synergistic was observed after treatment with glycine and alanine together in T320-280 (45.7%). In contrast to PA embryonic development, the stimulating effect by the culture in T320-280 was not observed in SCNT blastocyst development (27.6% and 23.7% in T280-280 and T320-280, respectively) whereas the number of inner cell mass cells was significantly increased in T320-280 (6.1 cells vs. 9.6 cells). Glycine treatment significantly improved blastocyst formation of SCNT embryos in both T280-280 (27.6% vs. 38.0%) and T320-280 (23.7% vs. 35.3%). Our results demonstrate that IVC in T320-280 and treatment with glycine improves blastocyst formation of PA and SCNT embryos in pigs.

Nitric oxide (NO) has an important role in oocyte maturation and embryonic development in mammals. This study examined the effect of exogenous NO donor S-nitroso-N-acetylpenicillamine (SNAP) in a maturation medium on meiotic progression and embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. When oocytes were exposed to 0.1 μM SNAP for first 22 h of in vitro maturation (IVM) in Experiment 1, SNAP significantly improved blastocyst development in both defined and standard follicular fluid-supplemented media compared to untreated control (48.4 vs. 31.7-42.5%). SNAP treatment significantly arrested meiotic progression of oocytes at the germinal vesicle stage at 11 h of IVM (61.2 vs. 38.7%). However, there was no effect on meiotic progression at 22 h of IVM (Experiment 2). In Experiment 3, when oocytes were treated with SNAP at 0.001, 0.1 and 10 μM during the first 22 h of IVM to determine a suitable concentration, 0.1 μM SNAP (54.2%) exhibited a higher blastocyst formation than 0 and 10 μM SNAP (36.6 and 36.6%, respectively). Time-dependent effect of SNAP treatment was evaluated in Experiment 4. It was observed that SNAP treatment for the first 22 h of IVM significantly increased blastocyst formation compared to no treatment (57.1% vs. 46.2%). Antioxidant effect of SNAP was compared with that of cysteine. SNAP treatment significantly improved embryonic development to the blastocyst stage (49.1-51.5% vs. 34.4-37.5%) irrespective of the presence or absence of cysteine (Experiment 5). Moreover, SNAP significantly increased glutathione (GSH) content and inversely decreased the reactive oxygen species (ROS) level and mitochondrial oxidative activity in IVM oocytes. SNAP treatment during IVM showed a stimulating effect on in vitro development of SCNT embryos (Experiment 7). These results demonstrates that SNAP improves developmental competence of PA and SCNT embryos probably by maintaining the redox homeostasis through increasing GSH content and mitochondrial quality and decreasing ROS in IVM oocytes.

Interferon tau (IFNT), has known as a key signal molecule for a period of pregnancy in ruminants owing to the need on maternal recognition of pregnancy. It is generated in trophectoderm cells of the elongation bovine conceptus at day 13-21 and a peak output is at day 15-17 of pregnancy period. Moreover, other studies indicated that it can be effective in the embryonic development and quality. In previous study, there were 8 bovine IFNT, but only 2 forms of IFNTs, IFNT2 and IFN-tau-c1, were expressed by the conceptuses during the peri-implantation. In this study, we target the one between the two, IFN-tau-c1 and then the effect of IFNT knockout in donor cells to bovine cloned embryonic development by somatic cell nuclear transfer (SCNT) was investigated. In order to proceed this study, the immature oocytes from the ovaries at local slaughterhouse have been matured in vitro for 22 hours. For preparing the donor cell that have a mutation on IFNT gene, somatic cells were transiently transfected with Cas9 protein and single guide RNA targeting IFNT, and various single derived colonies with high proliferation were isolated and confirm the mutation by PCR. Finally, one colony had mono-allelic mutation (4bps deletion) was picked out and applied as the donor cell to SCNT. A donor cell was injected into an oocyte that nucleus was removed. Reconstructed oocytes with the donor cell were fused by electrical shock, activated by chemical stimulation and cultured for 7 days in chemically defined medium. In this study, control (n=199) and IFNT knockout-group (n=219) were compared with four replications. As results, there was no significant difference between control-and IFNT-knockout group not only in cleavage rate, but also blastocyst formation rate (Control: 12.3% ± 9.2, IFNT knockout-group: 20.1 ± 11%). In addition, the number of blastocyst cell was not different between control (91.7 ± 26.2) and IFNT knockout group (83.5 ± 21.3). Some IFNT mutated blastocysts from SCNT were randomly selected for confirmation of the deletion of IFNT and all samples were positive for mutation. In conclusion, these data indicated that the interruption of IFNT did not influence the embryonic development. In future study, we will transfer these mutated embryos toto test the effect of IFNT for pregnancy period. This work was supported by BK21 PLUS Program for Creative Veterinary Science, the National Research Foundation of Korea (2017R1A2B3004972) and the Technology Development Program (S2566872) by MSS.

This study was conducted to establish the optimal chemical post-activation conditions in porcine embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) using 4 different chemical compositions (cytochalasin B (CB), cyclohexamide (CHX), demecolcine (DC), 6-dimethylaminopurine (DMAP). Porcine embryos were produced by PA and SCNT and then, cultured for post-activation with CB (7.5 μg/mL), CB (7.5 μg/mL) + CHX (10 μg/mL), CB (7.5 μg/mL) +DC (0.4 μg/mL), and CB (7.5 μg/mL) + DMAP (2 mM). In PA embryonic development, cleavage rates have been significantly higher in CB group (94.7%) and CB+DMAP group (94.1%) than that of CB+CHX and CB+DC group (88.1 and 84.3%, respectively). There have been no significant differences in blastocyst formation rates among the four groups. In cell number of blastocyst was shown in CB group (42.3%) significantly higher than CB+CHX and CB+DC group (40.6 and 40.6%, respectively). In SCNT embryonic development, CB+DMAP group (89.7%) significant differences were found on embryo cleavage rates when compared with other three groups. Blastocyst formation rates in CB+DMAP group (26.9%) were significantly higher when compared with CB, CB+CHX, and CB+DC groups (25.5, 20.2, and 22.1%, respectively). In blastocyst cell number, CB+DMAP group (41.4%) was found higher significant difference compared with other three groups. Additionally, we have investigated survivin expression in early development stages of porcine SCNT embryos for more confirmation. Our results establish that CB group and CB+DMAP group for 4 h during post-activation improves pre-implantation improvement of PA and SCNT embryos.

Introduction Porcine embryonic stem cells (pESCs) derived from cloned embryos might be a useful animal model in biomedical research, however, establishment of cloned pESCs is difficult by its incomplete nuclear reprogramming. Here, we report the improved development competence of porcine cloned embryos by vitamin C (VC) supplement to establish the pESCs. Materials and Methods Slaughterhouse-derived oocytes were in vitro matured for 44h and parthenogenetic and cloned embryos were produced using matured oocytes. Both of embryos were cultured for 6 days in PZM-5 media and development rates were examined. Four different concentration of VC (0, 25, 50, 100, and 200 μg/ml) was supplemented in IVM and IVC media and preimplantation developments in the 5 groups were compared in both of embryos Results and Discussion In the cleavage rates of IVM group, significantly higher rate was shown in 50 mg/ml group than other groups (84.5 ± 0.6% vs. 69.8 ± 5.5, 75.7 ± 1.8, 80.4 ± 0.2, 72.4 ± 0.1%; P<0.05), respectively. Significantly higher rates of blastocyst development also were shown in 50 mg/ml group than other groups (27.0 ± 2.0% vs. 20.4 ± 1.4, 22.1 ± 1.3, 23.7 ± 1.2, 19.6 ± 1.3%; P<0.05), respectively. In the cleavage rate of IVC group, non-significantly different with each group (84.0 ± 1.3, 86.7 ± 1.0, 88.4 ± 1.4, 76.7 ± 3.0, 64.6 ± 4.4; P<0.05). In the blastocyst rate of IVC group, significantly higher rate was shown in 25mg/ml and 50 mg/ml group than other groups (22.3 ± 1.7, 23.8 ± 1.7% vs. 19.1 ± 1.3, 15.9 ± 1.0, 5.8 ± 1.5%; P<0.05) In conclusion, supplement of 50μg/ml of VC in IVM and IVC media enhanced the development of porcine parthenogenetic embryos and these results will be a helpful information in the development of porcine cloned embryos and derivation of its embryonic stem cells.

Polo-like kinase 1 (plk1) shows multiple events of somatic cell and mammalian oocyte division. In mice, Plk1 distributes to the centromeres from prophase to anaphase and compose spindle apparatus at different stages of mitosis in spindle organization. Somatic cell nuclear transfer (SCNT) has a number of advantages however it is difficult to apply to basic or translational researches due to its low cloning efficiency. The causes of this low cloning efficiency are unclear. However, they are attributed to the cumulative results of several biological and technical factors. In this study, a biological factor plk1 was investigated. B6D2F1 mice (7–8 weeks old) were superovulated with 10 IU of pregnant mare’s serum gonadotropin and 9 U of human chorionic gonadotropin (HCG) 48 hr later. The oocytes were then collected 14 hr after HCG injection and cultured on potassium simplex optimized medium (KSOM). The plk1-specific inhibitor BI2536 was used to understand the influence of plk1. The 2-cell stage embryos were assessed by fluorescence immunoassay. In consequence, all BI2536-treated embryos failed in the first mitotic division which showed plk1 have critical role in the first mitotic division of the mouse embryo. SCNT requires enucleation of oocyte and injecting a donor cell into the enucleated cytoplast. In this process, a respectable amount of plk1 that co-localize with nucleus may be removed together. Fluorescence immunoassay and qPCR were used to monitor the change of plk1 level during SCNT. There was significant difference between the control and enucleated embryos in the level of plk1. In all division-failure 2-cell embryos, incorrect positioning of plk1 was found. Taken together, this results demonstrate that plk1 is critical for successful mitotic division of mouse SCNT 1-cell embryos.

The nature of molecular mechanisms governing embryo development is largely unknown, but recent reports have demonstrated that proper execution of programmed cell death is crucial for this process. The main objective of this study is to examine the mode of programmed cell death during nuclear transfer embryos development in porcine. In particular, the relative employment of two major pathways in programmed cell death; e.g. apoptosis (type I) and autophagy (type II) was compared. Oocytes use in the study was matured in vitro in the presence of 10% FBS maturation medium. After nuclear transfer embryos were cultured for each programmed cell death control factor [Cysteamine(Cyst : 0.4mM), 3-methyladenine(3MA : 2.5mM) and Rapamycin(RP : 100nM)] in TCM-199 medium supplemented with 0.1% BSA. In this study results of among the blastocysts development in 3MA; PCNA, MAP1LC3A and ATG5 RNA gene expression level increased in the order of IVF<Cyst < 3MA < RP. However Casp-3 and TNF-r RNA gene expression level decreased in the order of IVF < 3MA and RP< Cyst. The expression of mTOR showed a pattern opposite to that of MAP1LC3A. That is, its expression was the lowest in Cyst group. And next experiments analysis of MMP expression patterns. Analysed this MMPs enzyme activation to evaluate the effectiveness of high quality brastocyst culture in porcine. In this results of the enzymatic activity of MMP-2 and MMP-9 was assessed in culture, the level of active MMP-9 was higher expression in the medium of each 3MA and RP treatment group, with the level of another treatment group being relatively higher. These results suggest that the autophagy activation culture medium is more effective for stable and innovative nuclear transfer embryos development.

본 연구는 국내 원자력방사선 관련 전시 및 교육 발전 방향을 모색하기 위하여 국내 원자력 홍보관의 전시물 및 전시패널을 내용에 따라 크게 4가지 범주로 분류하고, 과학커뮤니케이션의 6가지 요소로 분석하여 비율을 파악하였 다. 연구 대상은 국내 원자력 홍보관 총 4곳을 목적 표집하였으며, 일본의 원자력 과학관 1곳을 선정하였다. 연구 결과, 국내 모든 기관에서는 4가지 범주 중에서 개념에 해당하는 내용이 높은 비율로 나타났다. 그리고 전시물에 포함되어 있는 과학커뮤니케이션 요소는 개념(CON)과 흥미(INT)가 주를 이루었으며, 반면에 과학의 본성(NOS), 인식(AW), 즐거 움(ENJ), 의견(OP)은 제한적으로 나타났다. 본 연구결과를 통하여 다음과 같은 결론을 내릴 수 있다. 원자력 홍보관은 관람객에게 원자력방사능에 대한 다양한 측면의 정보를 제공하여 관람객 스스로 올바른 판단을 하고 과학적 태도를 향상시키며 과학커뮤니케이션 요소의 이해를 높일 수 있도록 과학적 소양인 양성을 위한 전문 비형식 교육기관으로써의 역할을 수행할 수 있어야 한다. 그리고 전시물에 반영하기 어려운 과학커뮤니케이션을 충족시킬 수 있도록 전문 도슨트 또는 해설사 양성을 위한 전문 프로그램 개발과 적용에 대한 지속적인 연구가 필요하다.

Abnormal epigenetic reprogramming of donor nuclei is supposed to be one of the factors that causes low development efficiency of mammalian somatic cell nuclear transfer (SCNT). Trichostatin A (TSA) is an inhibitor of histone acetylase, and so development of SCNT embryos could be increased by treatment with TSA. In the present study, we examined the effect of TSA on in vitro development of porcine embryos derived from NT (nuclear transfer) by investigating the status of histone acetylation in TSA-treated and control NT embryos and the expression of developmental related genes. In this study, we found that incubating　NT embryos with 40nM TSA for 24h after activation could improved the blastocyst formation rate from 13.7% to 32.5%. Thechange in histone acetylation level as a reslut of TSA treatment were validated using immunofluorescence and confocal microscopy. Immunofluorescence results indicated that the level of aetylation at histone 3 lysine 18 (AcH3K18) was increased at early embryo development stage after TSA treatment. furthermore, we compared the expression patterns of several genes (developmental related genes; Oct4, Sox2, Nanog, Cdx2, the imprinting genes; igf2r). TSA treatment improved the expression of development related genes such as Oct4, Cdx2, Nanog as well as the imprinted genes like igf2r. In conclusion, our results demonstrated that TSA treatment improves the in vitro development of porcine NT embryos, increased the global histone acetylation (AcH3K18) and enhances the expression of some developmentally important genes (Oct4, Cdx2, Nanog) at blastocyst stages.

To precisely assemble the fuel test rod, an orbital TIG welding system was designed and developed to accurately conduct orbital TIG welding for the nuclear fuel test rod. Using this system, a welding process needs to confirm the welding properties for orbital TIG welding. Therefore, preliminary weld tests were performed on the cladding tubes under various conditions, and the results show that the width and depth of HAZ of the cladding specimen welded using identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a welded end-point because of heat accumulation. The performance tests were conducted under the welding conditions considered through preliminary welding tests, and the properties of the specimens were conformed through surface and microstructure analyses.

This study was designed to evaluate the effect of bovine serum albumin (BSA) in a maturation medium on oocyte maturation and embryonic development in pigs. Immature pig oocytes were matured for 44 h in a medium supplemented with 0.4% (w/v) BSA, 0.1% (w/v) polyvinyl alcohol (PVA), or 10% (v/v) pig follicular fluid (PFF). After IVM, oocytes reached metaphase II stage were activated for parthenogenesis (PA) or used as cytoplasts for somatic cell nuclear transfer (SCNT). Nuclear maturation (89.5%, 90.7% and 91.3% for BSA, PVA and PFF, respectively) and intraoocyte glutathione contents (1.20, 1.16 and 1.00 pixels/oocyte for BSA, PVA and PFF, respectively) were not altered by the macromolecules added to maturation medium. IVM of oocytes in a medium containing BSA (21.4%) and PVA (20.7%) showed significantly lower blastocyst formation after PA than culture in medium with PFF (39.2%). After SCNT, oocytes matured in medium with BSA showed decreased embryonic development to the blastocyst stage (9.2%) compared to those matured in medium with PFF (28.9%), while 23.6% of SCNT oocytes matured in medium with PVA developed to the blastocyst stage. When the effect of BSA in a maturation medium during the first 22 h and the second 22 h of IVM in combination with PFF or PVA was examined, PVA-BSA showed a higher nuclear maturation (94.1%) than BSA-PFF (84.5%). However, there was no significant difference in the blastocyst formation among tested combinations (47.3, 52.2, 50.0, 44.4 and 49.0% for PFF-PFF, PFF-BSA, PVA-BSA, BSA-PVA and BSA-PFF, respectively). Our results demonstrate that BSA and PVA added to maturation medium can support oocyte maturation comparable to PFF-supplemented medium. However, maturation of oocytes in a BSA-containing medium decreases embryonic development after PA and SCNT when compared with the medium supplemented with PFF.

We investigate the effect of L-glutathione (GSH), an antioxidant, treatment during the somatic cell nuclear transfer (SCNT) procedures on the in vitro development and DNA methylation status of bovine SCNT embryos. Bovine in vitro matured (IVM) oocytes were enucleated and electrofused with a donor cell, then activated by a combination of Ca-ionophore and 6-dimethylaminopurine. The recipient oocytes or reconstituted oocytes were treated with 50 μM GSH during these SCNT procedures from enucleation to activation treatment. The SCNT embryos were cultured for 7 days to evaluate the in vitro development, apoptosis and DNA methylation in blastocysts. The apoptosis was measured by TUNEL assay and caspase-3 activity assay. Methylated DNA of SCNT embryos at the blastocyst stages was detected using a 5-methylcytidine (5-MeC) antibody. The developmental rate to the blastocyst stage was significantly higher (P<0.05) in GSH treatment group (32.5±1.2%, 78/235) than that of non-treated control SCNT embryos (22.3±1.8%, 50/224). TUNEL assay revealed that the numbers of apoptotic cells in GSH treatment group (2.3±0.4%) were significantly lower (P<0.05) than that of control (3.8±0.6%). Relative caspase-3 activity of GSH treated group was 0.8±0.06 fold compared to that of control. DNA methylation status of blastocysts in GSH treatment group (13.1±0.5, pixels/ embryo) was significantly lower (P<0.05) than that of control (17.4±0.9, pixels/embryo). These results suggest that antioxidant GSH treatment during SCNT procedures can improve the embryonic development and reduce the apoptosis and DNA methylation level of bovine SCNT embryos, which may enhance the nuclear reprogramming of bovine SCNT embryos.

To conduct a nuclear fuel irradiation test, the inside of the nuclear fuel rod must be assembled along with the test fuel, several different parts, and sensors, and then filled with high-pressure and high-purityhelium gas. Therefore, it is necessary to develop helium gas filling techniques that can achieve exact TIG (Tungsten Inert Gas) spot welding at a pin-hole of the nuclear fuel rod to fill helium gas into the nuclear fuel test rod. However, previous apparatuses do not have repeatability for TIG spot welding as they lack an electrode position control jig to exactly fix a TIG electrode in a high-pressure chamber, and they consume a large amount of helium gas. Therefore, a TIG spot welding apparatus was developed to easily and accurately conduct TIG spot welding and significantly reduce the gas consumption. In addition, the optimum welding conditions of this welding apparatus were established through various weld tests.

The objective of this study was to determine the effect of post-activation treatment with cytoskeletal regulators in combination with or without 6-dimethylaminopurine (DMAP) on embryonic development of pig oocytes after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT). PA and SCNT oocytes were produced by using in vitromatured pig oocytes and treated for 4 h after electric activation with 0.5 μM latrunculin A (LA), 10.4 μM cytochalasins B (CB), and 4.9 μM cytochalasins D (CD) together with none or 2 mM DMAP. Post-activation treatment of PA oocytes with LA, CB, and CD did not alter embryo cleavage (85.8～88.6%), blastocyst formation (30.7～ 32.4%), and mean cell number of blastocysts (33.5～33.8 cells/blastocyst). When PA oocytes were treated with LA, CB, and CD in combination with DMAP, blastocyst formation was significantly (P<0.05) improved by CB+DMAP (42.5%) compared to LA+DMAP (28.0%) and CD+DMAP (25.1%), but no significant differences were found in embryo cleavage (77.5～78.0%) and mean blastocyst cell number (33.6～35.0 cells) among the three groups. In SCNT, blastocyst formation was significantly (P<0.05) increased by post-activation treatment with LA+DMAP (32.9%) and CD+DMAP (35.0%) compared to CB+DMAP (22.0%) while embryo cleavage (85.5～85.7%) and blastocyst cell number (41.1～43.8 cells) were not influenced. All three treatments (LA, CB, and CD with DMAP) effectively inhibited pseudo-polar body extrusion in SCNT oocytes. The proportions of oocytes showing single pronucleus formation were 89.6%, 83.9%, and 93.3%, respectively with the increased tendency (P<0.1) by LA+DMAP and CD+ DMAP compared to CB+DMAP. Our results demonstrate that post-activation treatment with LA or CD in combination with DMAP improves pre-implantation development of SCNT embryos and the stimulating effect of cytoskeletal modifiers on embryonic development is differentially shown depending on the origin (PA or SCNT) of embryos in pigs.

Developmental potential of cloned embryos is related closely to epigenetic modification of somatic cell genome. The present study was to investigate the effects of applying histone deacetylation inhibitor, trichostatin A (TSA) to activated porcine embryos on subsequent development of porcine parthenogenetic and nuclear transfer embryos. Electrically activated oocytes were treated with 5 nM TSA for different exposure times (0, 1, 2 and 4 hr) and then the activated embryos were cultured for 7 days. The reconstructed embryos were treated with different concentrations of 0, 5, 10 and 25 nM TSA for 1 hr. Also 5 nM TSA was tested with different exposure times of 0, 0.5, 1, 2 and 4 hr. And fetal fibroblast cells were treated with 50 nM TSA for 1, 2 or 4 hr and with 5 nM TSA for 1 hr. Cumulus-free oocytes were enucleated and reconstructed by TSA-treated donor cells and electrically fused and cultured for 6 days. In parthenogenetic activation experiments, 5 nM TSA treatment for 1 hr significantly improved the percentage of blastocyst developmental rates than the other groups. Total cell number of blastocysts in 1 hr group was significantly higher than other groups or control. Similarly, blastocyst developmental rates of porcine NT embryos following 5 nM TSA treatment for 1 hr were highest. And the reconstructed embryos from donor cells treated by 50 nM TSA for 1 hr improved the percentage of blastocyst developmental rates than the control group. In conclusion, TSA treatment could improve the subsequent blastocyst development of porcine parthenogenetic and nuclear transfer embryos.

The technique of SCNT is now well established but still remains inefficient. The in vitro development of SCNT embryos is dependent upon numerous factors including the recipient cytoplast and karyoplast. Above all, the metaphase of the second meiotic division (MII)　oocytes have typically become the recipient of choice. Generally high level of MPF present in MII oocytes induces the transferred nucleus to enter mitotic division precociously and causes NEBD and PCC, which may be the critical role for nuclear reprogramming. In the present study we investigated the in vitro development and pregnancy of White-Hanwoo SCNT embryos treated with caffeine (a protein kinase phosphatase inhibitor). As results, the treatment of 10 mM caffeine for 6 h significantly increased MPF activity in bovine oocytes but does not affect the developmental competence to the blastocyst stage in bovine SCNT embryos. However, a significant increase in the mean cell number of blastocysts and the frequency of pregnant on 150 days of White-Hanwoo SCNT embryos produced using caffeine treated cytoplasts was observed. These results indicated that the recipient cytoplast treated with caffeine for a short period prior to reconstruction of SCNT embryos is able to increase the frequency of pregnancy in cow.