• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.81-86
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• 2006

Embryotoxicity tests were performed in Daphnia magna to assess aquatic ecotoxicity of bisphenol A, a well known industrial compound showing estrogen-like activity in vivo, and to examine their effectiveness in the toxicological assessment. The whole embryonic developmental period was classified into 6 stages and developmental abnormality was checked to evaluate the embryotoxicity. In the present study, bisphenol A showed the ability to interfere with embryonic development, suggesting its antiecdysteroidal activity. The rates of mortality, delayed development, deformity and immobility all showed good concentration-response relationship, demonstrating their possibility as useful toxicological indices in daphnid embryotoxicity tests that have been rarely performed so far. It seemed favorable to the test sensitivity that embryos are removed from maternal daphnids around 7 hr after deposition from the ovaries to the brood chamber. These results suggest that daphnid embryotoxicity tests can be one of useful tools available for the assessment of ecotoxicity of various chemicals in the aquatic environment.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.60-60
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• 2001

Human thrombopoietin (hTPO) is a cytokine that plays a central role in megakaryopoiesis by influencing on the development and maturation of megakaryocyte and platelet production. To induce hTPO production in the mammary gland, expression vector was constructed by combining the promoter of bovine beta-casein gene, cDNA of hTPO and neomycine resistance gene for transfection into fibroblasts. Bovine fibroblast cells derived from female ear skin were transfercted with the expression vector using Lipofectamine (Life Technology, NY). Transected cells resistant to G4l8 treatment (600 $\mu\textrm{g}$/$m\ell$) were recovered and colony formation was initiated at 13 days. The colonies with about 1 cm diameter were picked and analysed by PCR. Single transfected cells were individually transferred to enucleated oocytes. After electrofusion, the reconstructed embryos were exposed to calcium ionophore (5uM) for 5 min followed by treatment with 6-DMAP (2.5 mM) for 4h. The nuclear transfer embryos were cultured in CRlaa medium at 38.5C, 5% $CO_2$ for 7 days. Twenty three of 29 (79.3%) colonies were proved to be hTPO transfectants by PCR. The colonies were further passaged and used to produce transgenic embryos using nuclear transfer. Cleavage and developmental rates of reconstructed embryos to the blastocyst stage were 65.1% and 39.4%, respectively Of 22 blastocysts that developed from reconstructed embryos with the transfected cell, 20 embryos (90.9%) were positive for hTPO by using PCR analysis. The results suggest that somatic cell nuclear transfer is efficient for production of transgenic embryos.

• Reproductive and Developmental Biology
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• v.36 no.3
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• pp.173-181
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• 2012

Sphingosine-1-phosphate (S1P) has a many function involved proliferation, differentiation and survival of many cells. In this study, to investigate whether S1P improve the developmental competence of porcine embryos, 50 nM of S1P were supplemented during in vitro maturation (with EGF or without EGF) medium and/or in vitro culture (IVC) medium. Addition of S1P was significantly increased the rate of oocytes reaching metaphase II (MII) compared to the control (83.5 vs. 64.1%) in without EGF medium, but not with EGF medium (89.5 vs. 84.6%). When treated with $1{\mu}M$ of N1N-dimethylsphingosine (DMS), a sphingosine kinase inhibitor which is blocked endogenous generation of S1P, the meiotic progression rates to MII stage (without EGF: 45.2 and with EGF: 66.7%) were significantly decreased and degeneration rates (without EGF: 51.2 and with EGF: 30.1%) were increased in both medium compared to control group during IVM periods. Also, the rates of blastocyst formation was significantly increased in the S1P treated group compared to control group (29.0 vs. 19.2%) of EGF supplemented medium, whereas there were no effect in the EGF free medium (9.0 vs. 10.5%). After 12 h IVM, the phosphorylation of ERK1 and ERK2, which is major signaling pathway of MAP kinase, were increased in the S1P group than that of control or DMS group. When supplemented of S1P during IVC, the rates of blastocyst formation and total cell number (30.2% and 40.6) were significantly increased in S1P-treated group compared with control (20.1% and 32.5), DMS (12.3% and 25.1), and S1P plus DMS group (24.7% and 33.6). The percentage of apoptosis nuclei in the S1P group was significantly decreased than other groups. Also, the rates of blastocyst formation (26.7 vs. 14%) and total cell number (42.8 vs. 32.5) were significantly increased in the S1P group than those of control group when S1P added during the entire IVM and IVC periods. Taken together, our results indicate that S1P supplementation in IVM and/or IVC medium affects beneficial effect of meiotic maturation and subsequent developmental competence of porcine embryos.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.189-203
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• 1999

To determine sex of bovine embryos using hamster histocompatibility Y(H-Y) antibodies, bovine compact morulae were incubated for 6 hours in TCM199 supplemented with 10% hamster H-Y antiserum and the embryos with developmental arrest were diagnosed as male embryos, while the embryos showing development during the incubation as female embryos. This presumptive embryo sexing was confirmed by polymerase chain reaction(PCR)method. 1. In the result of hamster sperm cytotoxicity test to measure H-Y antibody titer, the rate of dead sperm was considerably lower in H-Y antiserum absorbed with hamster male splenocytes than in H-Y antiserum absorbed with hamster female splenocytes or H-Y antiserum unabsorbed with splenocytes(p<0.01). 2. The rate of oocytes fertilized in vitro and the rate of blastocysts of the fertilized oocytes were 58.5% and 32.4%, respectively. The rate of blastocysts on day 8 was 15.9%, denoting the highest rate during whole culture period posterior to in vitro fertilization (IVF). 3. The bovine 16 cell and compact morulae embryos incubated in the medium supplemented with hamster H-Y antibodies showed 37.1% and 48.9% of developmental arrest which were diagnosed as male, respectively, and rates of redeveloped embryos from the arrested were 24.1% in 16 cell and 44.3% in compact morulae embryos, respectively, denoting higher rate of sex determination and rate of redevelopment in compact morulae than 16 cell embryos. 4. Bovine compact morulae of Korean cattle and Holstein were treated with hamster H-Y antibodies for sex determination and the rates of developmental arrest(diagnosed as male) were 48.4% for Korean cattle and 47.9% for Holstein, respectively. The rates of redeveloped embryos to blastocyst after treatment were 42.6% for Korean cattle and 41.8% for Holstein, respectively, showing no significant differences of sex determination and redevelopment between both breed. 5. The sex determination of bovine embryos(Korean cattle and Holstein) using hamster H-Y antibodies was diagnosed by PCR for confirmation, denoting the rates of 86.1% for Korean cattle and 85.9% for Holstein male embryos, respectively, and the rates of 91.9% for Korean cattle and 90.1% for Holstein female embryos, respectively, with no significant differences of sex determination between both breed. These results indicated that hamster H-Y antibodies can be usable for sex determination of bovine embryos of Korean cattle and Holstein, the viability of bovine embryos was sustained while being cultured in the medium supplemented with hamster H-Y antibodies of appropriate titer and sex determination of bovine embryos by PCR can be feasible for confirmation.

• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.239-250
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• 1996

The objective of the present experiments were to determine whether micromanipulative and electro-stimulation conditions for blastomere survival overlapped those for oocyte activation in porcine. Eggs selected for in vitro development potential of blastomeres isolated from 4-cell embryos and oocyte activation by electrostimulation were equilibrated for 5~10 min, in 0.3M sucrose solution containing 7.5$\mu\textrm{g}$/ml cytochalasin B, and then electrostimulated for 30$\mu$sec using one pulse of 100, 120, 150 or 180 volts DC with electrodes 0.2mm apart. Single blastomeres were inserted into empty zona pellucida prior to electrostimulaticn. Then they were cultured in 20${mu}ell$ drops of fresh BECM to observe their developmental ability in vitro in a humidified incubat or at 38.5$^{\circ}C$. The results obtained from these experiments are as follows : 1. When one pulse of 100, 120, 150 or 180 volts DC for 30$\mu$sec were applied to porcine oocytes having the slit formed on zona pellucida for activation, activation rates were 65.1, 66.7, 70.7 and 91.7%, respectively. Higher activation rate was observed in 180V. 2. Infact oocytes incubated for 30 min, in 0.3M sucrose solution after electrostimulation were significantally different from control group with increasing of voltages(p<0.05). When voltages used for electrostimulation were increased, activation rates of oocytes were improved in all treatment groups. 3. When zona punctured-oocytes were only electrostimulated, or incubated in 0.3M sucrose solution for 30 min. after electrostimulation at 180 volt DC, activation rates were 90.5 and 95.5%, respectively. And activation rates of zona punctured-oocytes were significantly different from the groups for which zona pellucida was not punctured(P<0.05). 4. When single blastomeres form 4-cell transferred into empty zona pellucida were incubated for 0, 15 and 30 min. in 0.3M sucrose solution after electrostimulation using one pulse of 180 volt DC for 30 $\mu$sec, developmental rates of electrostimulated-single blastomeres to blastocyst were 72.5, 59.0 and 51.2%, respectively, and the ratio of control group developed to blastocyst were 80.0%. 5. The average cell number in electrostimulated-blastomeres developed to blastocyst were 7.9~10.8, and reduced than the cell number in diploid control ; Also cell number decreased with increasing of voltages. The results of these experiments indicate that the optimal condition for achieving in vitro developmental ability of single 4-cell blastomeres and oocyte activatin is 1 pulse, duration 30 $\mu$sec. in 180 volt, and incubation of blastomeres and oocytes in 0.3M sucrose solution after electrostimulation was not significantally different from another treatment groups. The results also show that this condition is suitable for nuclear transplantation using porcine eggs.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.379-387
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• 2011

Copepod nauplii plays an important role as a linker between the microbial food web and classical food chain in marine ecosystem and is an essential food source for early stage of many larval fishes. Study on the influencing factors on the growth of copepod naupliar stages has been rarely carried out in despite of these ecological significances. Many studies have shown that food availability and temperature are major factors to influence copepod growth. However, due to the complicated environment parameters in coastal ecosystem, the relationships between growth of copepods and influencing factors are still unclear under the natural condition. Growth rates of the copepod $Acartia$ $hongi$ nauplii were measured in Kyeonggi Bay from February to December 2001. $Acartia$ $hongi$ is numerically abundant and widespread predominant species in the coastal regions of the Yellow Sea and occurs continuously throughout the year, with a maximum peak in late spring. The naupliar growth rates of $Acartia$ $hongi$ by the artificial cohort method varied from 0.03 to 0.18 $day^{-1}$, with a mean of 0.09 $day^{-1}$. The overall naupliar growth rates showed a significantly positive relationship with the variation in water temperature. However, Previous study reported that the growth rates of adult $Acartia$ $hongi$ were primarily influenced by the variation in chlorophyll-$a$. Therefore, these differences demonstrated that the influencing factors of growth did not correspond with the developmental stages. The results of this study suggest that the dissimilarity of growth between nauplius and adult female resulted from the size-dependant difference in food availability and the growth of older developmental stages containing adults are more food-dependent than juveniles.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.171-180
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• 2011

In this study I report that in vitro development rates of bovine nuclear transfer embryos activated either with boar sperm cytosolic factor (SCF) or with ionomycin followed by cycloheximide (CHX) and subsequent in vivo developmental rates after embryo transfer are related to blastocyst quality as evaluated by apoptosis analysis. SCF was extracted from porcine semen then purified for post-activation injection after nuclear transfer. The optimal timing for SCF injection was determined to be at least 22 h post-IVM for parthenogenetic activation of bovine oocyies. A total of 364 oocytes were successfully enucleated and 268 (73.6%) fused and were injected with SCF. The survival rate of fused and injected embryos was 109/113 (96.5%) after 2 h. The cleavage rates of nuclear transfer embryos after 3 d of culture in the ionomycin/CHX treated group were significantly higher than those of the SCF-activated group (93.3% vs 81.7%, p<0.01, respectively). However, at 7 d and 9 d there was no significant difference between the total developmental rates to blastocyst for either treatment group. Total blastocyst cell numbers were also not significantly different between the two activation treatments (ionomycin/CHX: 149.5${\pm}$7.7 vs. SCF: 139.3${\pm}$4.4 cells). In contrast, the apoptotic levels in the SCF blastocysts were higher than those produced after the chemical treatment (28.2${\pm}$5.1% vs. 8.8${\pm}$0.6%, respectively). A total of 18 expanded or hatching blastocysts was transferred to nine synchronized recipients in each activation group; 5/9 (55.5%) and 2/9 (22.2%) were pregnant at 40 d in the ionomycin/CHX treatment and SCF activated group, respectively. However, only one went to term in the ionomycin/CHX treatment while none of the pregnancies from the SCF group were maintained by 90 d. In conclusion, these results suggest that SCF derived from different species is a limited activator to be used for activation after bovine nuclear transfer in lieu of a chemical activation protocol.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.42-42
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• 2001

The objective of this study was to assess the development of porcine follicular oocytes fertilized by ICSI. Cumulus-oocyte-complexes (COCs) were collected by aspiration from follicles of 2-7 mm in diameter from a local slaughterhouse ovaries. Oocytes matured for 40-44 h were centrifuged at 12,000g for 6 min and then injected with sperm prepared by swim-up procedure in the presence or absence of 5 mM dithiothreitol (DTT). Injected oocytes were cultured in NCSU 23 medium during 6 to 8 days. IVF controls were compared to those of resulting embryos. The results obtained were as. follow: 1, The rates of cleavage and development rates into blastocyst by ICSI were not significantly (P<0.05) different between with (53.0% and 19.7%) or without (48.3% and 23.8%) centrifugation, respectively. 2. The cleavage and developmental rates to blastocyst after ICSI with or without 5mM DTT treated-sperm were not significantly (P<0.05) different (60.4% vs 16.4% and 48.5% vs 22.2%, respectively). 3. The cleavage and the developmental rates to blastocyst were not significantly (P<0.05) different between the zygotes obtained by IVF (51.8% vs. 22.4%) and ICSI (51.4% vs. 21.6%). 4. The number of blastomere in blastocyst stages after IVF or ICSI was not significantly different (46.7 $\pm$2.9 and 41.9$\pm$4.6).

• Journal of Educational Research in Mathematics
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• v.8 no.2
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• pp.745-752
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• 1998

컴퓨터의 급속한 보급으로 시각화는 수학 교육자사이의 논의에 자주 등장하는 소재가 되었다. 우리는 다양한 소프트웨어를 사용하여 준비한 수업에 학생들로 임하게는 하지만 거의 그들의 사고 발달과정에는 관심을 갖지 못하고 있다. 이 논문은 구성주의(Constructivism)와 정보처리체계(Information-Processing System)에 입각하여 수학의 시각화를 생각해보고 어떻게 시각화 환경을 준비해야하는지 논해보고자 하였다. 구성주의의 시각화에서는 반영적 추상(reflective abstraction), 반복되는 경험(repeated experience), 그리고 지식 위계성이 학습의 기능 체계를 이루므로 발견적 학습을 통해 학생 스스로 의미를 구성할 수 있도록 Thomas (1992)의 세 가지 제안을 이용하여 수업을 준비할 수 있다. 정보처리체계에서는 지식은 서술적인 것과 과정적인 것으로 나뉘어지고, 시각적 표상을 수록하고 삭제하는 과정과 조작 가능한(manipulative) 환경과의 상호작용으로 기호적 시각으로 표상을 변화하는 과정을 통해 개념을 습득하게된다. 시각화는 스키마와 개념상을 통해서 일어난다. 그래프, 애니메이션, 그리고 다른 시각적 표상 등은 이 개념상에 직접적 효과를 주므로 매우 중요하다. 이런 논란을 바탕으로 교사는 반영적 추상화를 위해 시간을 충분히 제공해야하고, 비슷한 문제를 가지고 여러번 시도를 할 수 있게 하며, 학생을 잘 관찰하여 그들의 지식 위계성을 이해하고 방향을 제시하며, 논리적이고 잘 연결된 시각적 표상을 제공하고, 상징적 사관으로 확장할 수 있게 조작할 수 있는 환경에서 시각화에 대해 학생과 많은 대화를 하도록 수업을 준비해야한다. 그한 예로 타원을 가르치기 위해 몇 가지 테크놀로지를 활용한 시각화 환경을 구성해보았다.ates of bisected bovine embryos by micromanipulator and micropipett were 29.2% and 19.1%, respectively. The rates of non-bisection embryos(46.7%) were significantly higher than those of bisection embryos. 2. The in vitro developmental rates of bisected bovine embryos by micromanipulator, micropipett and pipetting method were 32.4%, 19.4% and 25.6%, respectively.3. The in vitro developmental rates of with and without-zona pellucida of bisected bovine embryos by raicromanipulator were 30.8% and 25.0%, respectively. The rates of nonbisection embryos(53.1%) were significantly higher than those of bisection embryos.랑크톤 군집내 종 천이와 일차생산력에 크게 영향을 미칠 수 있음을 시사한다.TEX>5.2개)였으며, 등급별 회수율은 각각 GI(8.5%), GII(13.4%), GIII(43.9%), GIV(34.2%)로 나타났다.ments of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to

• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.227-233
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• 2004

This study was conducted to investigate the effect of various addition and exclusion time of glucose (Control: no addition, A: 24～72 h, B: 24～48 h, C: 48～72 h, D: 0～72 h, E: 0～48 h, F: 0～24 h and 48～72 h, G: 0～24 h) on embryonic developmental capacity of 2-cell embryos in mice. Developed blastocysts were assessed for mean cell number by differential staining. The zona-intact blastocyst (ZiB) rates were higher (p<0.05) in group B than control. However, the zona-escape blastocyst (ZeB) rates were not significantly different in all groups. At 72 h, total blastocyst (ZiB + ZeB) formation rates were not significantly different in all groups. The mean cell number was not significantly different among all groups. The inner cell mass (ICM) cell number was higher (p<0.05) in group F than control, group A, B and G. The trophectoderm (TE) cell number was higher (p<0.05) in control than group A and D. The %ICM was higher (p<0.05) in group C, D and F than control. The ICM : TE ratio was not significantly different in all groups. Between control and glucose group, no significant difference was observed in the total blastocysts (ZiB + ZeB) formation rates. Also, no significant difference was observed in the mean cell number, ICM cell number and ICM : TE ratio. However the TE cell number was higher (p<0.05) in control than glucose group and %ICM was higher (p<0.05) in glucose group than control. In conclusion, glucose added in culture medium was not inhibitory on blastocyst formation but glucose added for 48 ～72 h in culture medium increases %ICM of blastocysts in mice.