• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 1997년도 제28차 창립30주년 기념 추계학술대회
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• pp.52-52
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• 1997

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 공동 춘계학술대회
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• pp.63.1-63
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• 1999

No Abstract, See Full Text

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.182.1-182
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• 1999

No Abstract, See Full Text

• 한국수정란이식학회지
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• 제31권2호
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• pp.131-136
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• 2016

Since the first success of animal cloning, somatic cell nuclear transfer presented various ideas in many research areas such as regenerative medicine. However, SCNT embryos has poor survival rate. Therefore, numerous researches carried out to enhance the developmental capability of porcine nuclear transfer embryos. Cytochalasin B, demecolcine, latrunculin A, cycloheximide and 6-dimethylaminopurine are efficient chemicals treated in post-activation procedure to increase the efficiency of SCNT. This review study is aim to investigate the effects of these chemicals applied to post-activation in porcine SCNT. Cytochalasin B, demecolcine, latrunculin A are cytoskeletal manuplators inhibit extrusion of pseudo-polar body. Cytochalasin B and demecolcine showed considerably higher blastocyst formation proportion (26-28%) compared to when they are not treated (16%). And when latrunculin A was treated for postactivation, blastocyst formation proportion was increased in SCNT embryos exposed to LA (38%) than those in control (14%). On the other hand, cycloheximide and 6-dimethylaminopurine are protein synthesis and kinase inhibitors. And they help to maintain $Ca^{2+}$ fluctuation in oocytes. Cleavage and blastocyst rates of NT embryos were increased when they were exposed to CHX (16.9% and 5.4% with no CHX).And 6-DMAP also showed higher blastocyst formation (21.5% compared to 15.7%, control). Although all these chemicals have different mechanisms, they showed developmental competence enhancement in NT embryos. However, there are only few studies comparing each chemical's post-activation effect. Therefore, further research and study should be conducted to find optimal chemical for improving the efficiency of SCNT.

• 대한의생명과학회지
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• 제12권1호
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• pp.17-22
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• 2006

The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.

• 한국발생생물학회지:발생과생식
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• 제22권3호
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• pp.245-252
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• 2018

To improve survival rates of vitrified pig oocytes, the treatment of cytoskeletal stabilizer on an appropriate time is one of the possible approaches. However, the exact treatment timing and effect of cytoskeletal stabilizer such as cytochalasin B (CB) is not well known during oocyte vitrification procedures. Thus, the present study was conducted to determine optimal treatment timing of CB during vitrification and warming procedures. In experiment 1, the survival rates of the postwarming pig oocytes were analyzed by fluorescein diacetate (FDA) assays with 4 classifications. In results, post-warming oocytes showed significantly (p<0.05) decreased number of alive oocytes (31.8% vs. 86.4%) compared to fresh control. In detail, the significant difference (p<0.05) was found only in strong fluorescence (18.2% vs. 70.5%) not in intermediate fluorescence groups (13.6% vs. 15.9%). In experiment 2, CB was treated before (CB-Vitri) and after (Vitri-CB) vitrification. In results, group of Vitri-CB showed significantly (p<0.05) higher (91.6%) survival rates compared to group of CB-Vitri (83.7%), significantly (p<0.05) and comparable with group of Vitri Control (88.7%) by morphological inspection. In FDA assay results, group of Vitri-CB showed significantly (p<0.05) higher (44.2%) survival rates compared to groups of CB-Vitri (36.7%) and Vitri Control (35.1%). In conclusion, the increased survival rates of post-warming pig oocyte treated with Vitri-CB method are firstly described here. The main finding of present study is that the CB treatment during recovery could be helpful to refresh the post-warming pig oocyte resulting its improved survival rates.

• 한국수정란이식학회지
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• 제29권2호
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• pp.111-117
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• 2014

This study was conducted to optimize the efficiency of cloning and to produce cloned mice. The majority of cloned mammals derived by nuclear transfer (NT) die during gestation and have enlarged and dysfunctional placentas. In this study, the optimized conditions were established to produce clone mice. The parthenogenetic oocytes were activated after 6 h regardless of cytochalasin B (CB) concentration. CB treatment ($2{\mu}g/ml$) was found second polar body. Lower concentration of CB was decreased the activation rate, but the second polar body was the best highly increased during 6 h incubation. The small fragments were exhibited in the $5{\mu}g/ml$ treatment of CB, but it was not found in lower concentration groups (> $2.5{\mu}g/ml$). To examine effects of $SrCl_2$ on the adult cumulus cells, somatic cell NT oocytes were exposed during 0.5, 1 and 6 hrs. The second polar body was significantly greater in 0.5 h exposure group (6.6%) than 1, 6 hrs. Developmental rate from 2-cell to 4-cell was the lowest in 7.5 mM Strontium chloride ($SrCl_2$) groups (84.1% and 64.3%) than 5, 10 m $MSrCl_2$. The implantation rate was not significantly difference among 5, 7.5 and 10 m $MSrCl_2$ group. Three live fetuses were produced by SCNT. SCNT placentas were remarkably heavier than IVF group (8 fetuses) (0.34, 0.34, 0.33 vs 0.14 g) compared with the placenta weight of IVF and SCNT clones.

• 한국수정란이식학회지
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• 제28권2호
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• pp.127-132
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• 2013

The objective of this study was to examine the effect of in vitro maturation (IVM) medium, cytochalasin B (CB) treatment during intracytoplasmic sperm injection (ICSI), and electric activation on in vitro development ICSI-derived embryos in pigs. Immature pig oocytes were matured in vitro in medium 199 (M199) or porcine zygote medium (PZM)-3 that were supplemented with porcine follicular fluid, cysteine, pyruvate, EGF, insulin, and hormones for the first 22 h and then further cultured in hormone-free medium for an additional 21~22 h. ICSI embryos were produced by injecting single sperm directly into the cytoplasm of IVM oocytes. The oocytes matured in PZM-3 with 61.6 mM NaCl (low-NaCl PZM-3) tended to decrease (0.05

• 대한의생명과학회지
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• 제14권3호
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• pp.179-186
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• 2008

Matrix metalloproteinases (MMPs), also designated matrixins, hydrolyze components of the extracellular matrix. These proteinases playa central role in many biological processes, such as embryogenesis, normal tissue remodeling, wound healing, and angiogenesis, and in diseases such as atheroma, arthritis, cancer, and tissue ulceration. In previous data, disruption of the actin cytoskeleton by cytochalasin D (CD) inhibited NO-induced apoptosis, dedifferentiation, cyclooxygenase (COX)-2 expression, and prostaglandin $E_2$ production in chondrocytes cultured on plastic or during cartilage explants culture. In this study, we investigated the effects of the actin cytoskeleton architecture on MMP-2 expression and dedifferentiation by CD in rabbit articular chondrocytes. Rabbit articular chondrocytes were prepared from cartilage slices of 2-weeks-old New Zealand white rabbits by enzymatic digestion. CD was used as a disruptor of actin cytoskeleton. In this experiments measuring CD dose response, primary chondrocytes were treated with various concentrations of CD for 24h. The actin disruption was determined by immunostaining. MMP-2 expression levels were determined by immunoblot analysis and Reverse transcriptase-Polymerase chain reaction (RT-PCR) and MMP-2 activity was determined by gelatin zymography. We found that cell morphological change and up-regulation of MMP-2 expression by CD as determined via immunostaining, gelatin zymography and immunoblotting. Moreover, CD induced MMP-2 transcription was detected by RT-PCR. Also, CD-induced type II collagen expression was inhibited by MMP-2 inhibitor I treatment. Our results indicate that CD up-regulated MMP-2 activation causes dedifferentiation of articular chondrocyte.

• Biomolecules & Therapeutics
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• 제22권4호
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• pp.295-300
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• 2014

The actin cytoskeleton plays an important role in macrophage-mediated inflammatory responses by modulating the activation of Src and subsequently inducing nuclear factor (NF)-${\kappa}B$ translocation. In spite of its critical functions, few papers have examined how the actin cytoskeleton can be regulated by the activation of toll-like receptor (TLR). Therefore, in this study, we further characterized the biological value of the actin cytoskeleton in the functional activation of macrophages using an actin cytoskeleton disruptor, cytochalasin B (Cyto B), and explored the actin cytoskeleton's involvement in morphological changes, cellular attachment, and signaling events. Cyto B strongly suppressed the TLR4-mediated mRNA expression of inflammatory genes such as cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-${\alpha}$, and inducible nitric oxide (iNOS), without altering cell viability. This compound also strongly suppressed the morphological changes induced by lipopolysaccharide (LPS), a TLR4 ligand. Cyto B also remarkably suppressed NO production under non-adherent conditions but not in an adherent environment. Cyto B did not block the co-localization between surface glycoprotein myeloid differentiation protein-2 (MD2), a LPS signaling glycoprotein, and the actin cytoskeleton under LPS conditions. Interestingly, Cyto B and PP2, a Src inhibitor, enhanced the phagocytic uptake of fluorescein isothiocyanate (FITC)-dextran. Finally, it was found that Cyto B blocked the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) at 1 min and the phosphorylation of heat shock protein 27 (HSP27) at 5 min. Therefore, our data suggest that the actin cytoskeleton may be one of the key components involved in the control of TLR4-mediated inflammatory responses in macrophages.