• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.259-266
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• 2000

This study was carried out to investigate the embryonic developmental changes of the pineal gland during incubating period in the Korean pheasant. The pheasant embryos and fetuses were killed after 3, 4, 6, 9, 12, 15, 19 and 23 (hatching) days of incubation. The morphological characteristics of a pineal gland were determined in all embryos and fetuses using the whole - mount technique, light microscopy and morphometry. The time of the first apparition of the pineal anlage, as a derivative of the roof of the third ventricle, was fixed at 3 days of incubation. The pineal vesicles appeared as solid mammilliform projections, which subsequently presented a central lumen, at 4 days of incubation. The pineal parenchyma was composed of the tubular pineal recess, the lobules surrounded with septum originating from the capsule and the follicles possessed central lumen at 23 days of incubation. The length, width and area of the pineal gland were increased markedly at 9 and 15 days of incubation. These results suggest that the pineal recess has an important role in the pineal development after hatching.

• Development and Reproduction
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• v.23 no.4
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• pp.391-399
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• 2019

Nicotinamide is used to maturate pancreatic progenitors from embryonic stem cells (ESCs) into insulin-producing cells (IPCs). It has been known that nicotinamide inhibits the enzymatic activity of SIRT1, an NAD⁺-dependent deacetylase. Here we show that SIRT1 knockdown enhances the differentiation of human ESCs into IPCs. SIRT1 knockdown enhances the clustering size of IPCs and the expression of pancreatic genes including c-peptide, pancreas/duodenum homeobox protein 1 (PDX1), insulin, somatostatin, glucagon and Nkx6.1 in human ESC-derived IPCs. In addition, We found that IPCs differentiated from SIRT1 knockdowned human ESCs have more zinc compared to those from control human ESCs. Our data suggest that SIRT1 negatively regulates the differentiation of β cells from human ESCs.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.62-62
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• 2002

The relationship of Oct-4 to pluripotent cells is suggested by its tightly restricted expression pattern during embryonic development. Just prior to implantation it is limited to pluripotent cells of the inner cell mass (ICM) that will form the embryo proper but is not expressed in the trophectoderm, the structure that will form the extraembryonic tissues. (omitted)

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.75-79
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• 2006

The developmental regulation of the preimplantation mammalian embryos is a fundamental step for preparing the implantation and it may be regulated by several autocrine and paracrine factors including platelet-activating factor. PAF improved the embryonic survival and implantation but its role during blastocyst development is still largely unknown. In this study, the effects and the possible pathway of PAF on developmental regulation of blastocyst to hatching stage were investigated. Developmental pattern in hatching embryo was a concentration-response curve showing maximal activity at 1 nM PAF, with decreasing activity at higher concentrations. $50{\mu}M$ 1-(5-isoquinolimnesulfonyl)-2-methylpiperazinme dihydrochloride (H-7), a PKC inhibitor, inhibited the progression of blastocyst to hatching embryo. In addition H-7 blocked the PAF effects on the blastocyst development. Besides tetradecanoylphorbol acetate (TPA), a PKC activator stimulated development of blastocyst to the hatching stage. These finding revealed that PAF support the blastocyst development to the hatching embryo. Also it is suggested that PAF action pathways in hatching supporting include the PKC signaling pathway.

• Journal of Animal Science and Technology
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• v.58 no.3
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• pp.13.1-13.7
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• 2016

Background: In the present study, various freezing containers were tested for mouse embryos of respective developmental stages; embryos were vitrified and then their survival rate and developmental rate were monitored. Mouse two cell, 8 cell, and blastula stage embryos underwent vitrification freezing-thawing and then their recovery rate, survival rate, development rate, and hatching rate were investigated. Methods: EM-grid, OPS, and cryo-loop were utilized for vitrification freezing-thawing of mouse embryos. Results: It was found that recovery rate and survival rate were higher in the group of cryo-loop compared to those of EM-grid (p < 0.05). Embryonic development rate, two cell embryos to blastocyst, as well as hatching rate were higher in the control group compared to the EM-grid group and OPS group (p < 0.05), yet no difference was noted between the control group and cryo-loop group. Development rate and hatching rate of eight cell morulae and blastocysts were all lower in the treatment groups than the control group whilst hatching rate of blastocysts was higher in the control group compared to the groups of EM-grid and OPS (p < 0.05); although the cryo-loop group was shown to be slightly higher than other groups, it was not statistically significant. Conclusions: In the study, we investigate effects of freezing containers on vitrified embryos of respective developmental stages; it was demonstrated that higher developmental rate was shown in more progressed (or developed) embryos with more blastomeres. There was however, no difference in embryonic development rate was shown amongst containers. Taken together, further additional studies are warranted with regards to 1) manipulation techniques of embryos for various vitrification freezing containers and 2) preventive measures against contamination via liquid nitrogen.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.2
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• pp.153-161
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• 2014

The aim of this study is to investigate the effects of ambient thermal environments on the development of swallowtail butterflies (Sericinus montela Gray). Developmental durations and survival rates of S. montela were examined at two crucial developmental stages, embryonic and larval development, at varying temperatures ranging from $15^{\circ}C$ to $35^{\circ}C$. As expected, our results indicated that increasing temperatures decreased the developmental duration and survival rate of the eggs. However, the larvae and pupae showed maximum survival rates at $20.0^{\circ}C$ and $25.0^{\circ}C$, and the represented durations were similar to those of the eggs. Larval development was stage-specific, revealing that the fourth and fifth instars at the later stages were more susceptible to temperature variation. When considering both parameters, the optimal development of S. montela occurred within the temperature range of $20.0-25.0^{\circ}C$. The lower threshold for the complete development of S. montela from eggs to eclosion of adults was calculated at $10.6^{\circ}C$ by linear regression analysis. The estimated value is similar to that of other endemic insects distributed in temperate climate zones, which indicates that S. montela belongs to a small group of swallowtails adjusted to low ambient temperatures. From the results, we predict that the full development of S. montela could be achieved within the temperature range of $17.5-30.0^{\circ}C$. Embryonic development ceased at both test temperature extremes, and no further larval development proceeded after the third instar at $35.0^{\circ}C$. These results suggest that embryogenesis can be significantly influenced by slight variations in the ambient thermal environment that fall below the optimal range.

• Development and Reproduction
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• v.15 no.4
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• pp.331-338
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• 2011

MicroRNAs (miRNAs) function as a key regulator of diverse cellular functions. To find out novel miRNAs that promote the differentiation of mouse embryonic stem cells (mESCs), we compared the miRNAs expression profiles of mESCs under self-renewal vs. differentiation states. We noticed that miR-222 was highly expressed during the differentiation of mESCs. Quantitative RT-PCR analysis revealed that expression of miR-222 was up-regulated during the embryonic bodies formation and retinoic acid -dependent differentiation. When miR-222 was suppressed by antogomiR-222, the differentiation of mESCs was delayed compared to control. Self-renewal marker expression or cell proliferation was not affected but the expression of lineage specific marker was suppressed by the treatment of miR-222 inhibitor during the differentiation of mESCs. Taken together, these results suggest that miR-222 functions to promote the differentiation of mESCs by regulating expression of differentiation related genes.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.251-256
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• 2011

Presently, the effect of 0.5 mM dibutyryl cAMP (dbcAMP)-supplemented maturation medium during different incubation time on meiotic arrest (germinal vesicle) and resumption (metaphase II) of porcine oocytes and embryonic development of porcine oocytes following in vitro fertilization (IVF) or parthenogenetic activation (PA) was determined. Porcine cumulus oocyte complexes (COCs) were cultured in 0.5 mM dbcAMP for 17, 22, 27, or 42 h, and an additional 22 h without 0.5 mM dbcAMP. The nuclear status was examined at each time point. Oocytes cultured from 39~49 h displayed more than 80% meiotic resumption. More than 85 % of meiotic arrest was presented at 17~22 h. Oocytes were cultured for 22 h with 0.5 mM dbcAMP and additional 22 h without dbcAMP to assess developmental potential following IVF or PA. There were no significant differences in blastocyst rates among the dbcAMPIVF, IVF, dbcAMP-PA, and PA groups, although cleavage rate of IVF group was significantly higher than those of dbcAMP-PA, and PA groups. In conclusion, 0.5 mM dbcAMP influenced meiotic maturation of porcine oocytes depending on incubation time of oocyte, although embryonic development was not improved in both IVF and PA.

• Development and Reproduction
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• v.20 no.2
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• pp.149-155
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• 2016

Sprouty (Spry) genes encode inhibitors of the receptor tyrosine kinase signaling cascade, which plays important roles in stem cells. However, the role of Spry4 in the stemness of embryonic stem cells has not been fully elucidated. Here, we used mouse embryonic stem cells (mESCs) as a model system to investigate the role of Spry4 in the stem cells. Suppression of Spry4 expression results in the decreases of cell proliferation, EB formation and stemness marker expression, suggesting that Spry4 activity is associated with stemness of mESCs. Teratoma assay showed that the cartilage maturation was facilitated in Spry4 knocked down mESCs. Our results suggest that Spry4 is an important regulator of the stemness and differentiation of mESCs.

• Journal of Embryo Transfer
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• v.32 no.4
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• pp.267-274
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• 2017

Alpha lipoic acid (ALA) is a biological membranes compound. As the antioxidant, it decreases the oxidized forms of other antioxidant substances such as vitamin C, vitamin E, and glutathione (GSH). To examine the effect of ALA on the in vitro maturation (IVM) of porcine oocytes, we investigated intracellular GSH and reactive oxygen species (ROS) levels, and subsequent embryonic development after parthenogenetic activation (PA). Intracellular GSH levels in oocytes treated with 50uM ALA increased significantly (P < 0.05) and exhibited a significant (P < 0.05) decrease in intracellular ROS levels compared with the control group. Oocytes matured with 50 uM of ALA during IVM displayed significantly higher cleavage rates (67.8% vs. 83.4%, respectively), and higher blastocyst formation rates and total cell number of blastocysts after PA (31.6%, 58.49 vs. 46.8%, 68.58, respectively) than the control group. In conclusion, these results suggest that treatment with ALA during IVM improves the cytoplasmic maturation of porcine oocytes by increasing the intracellular GSH levels, thereby decreasing the intracellular ROS levels and subsequent embryonic developmental potential of PA.