• 대한생식의학회:학술대회논문집
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• 2002.11a
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• pp.57.1-57.1
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• 2002

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.194.3-194
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• 1997

• Clinical and Experimental Reproductive Medicine
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• v.33 no.1
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• pp.25-33
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• 2006

Objective: The aim of this study was to investigate whether embryonic stem (ES) cells can be established from isolated blastomeres of mouse embryos. Methods: Blastomeres were separated from mouse (C57Bl/6J) 2- or 4-cell embryos. Isolated blastomeres or whole 4-cell embryos were co-cultured with mitosis-arrested STO feeder cells in DMEM supplemented with recombinant murine leukemia inhibitory factor and ES-qualified fetal bovine serum. After the tentative ES cell lines were maintained from isolated blastomeres or whole embryos, some of them were frozen and the others were sub-cultured continually. Characteristics of tentative ES cell lines as were evaluated for specific genes expressions with immunocytochemistry and RT-PCR. Results: One ES cell line (3.0%) was established from isolated blastomere of 2-cell embryo and one cell line (4.0%) from isolated two blastomeres of 4-cell embryo. And five cell lines (16.7%) were established from whole 4-cell embryos. Both cell lines from isolated blastomere and whole embryo expressed mouse ES cell specific markers such as SSEA-1, Oct-4 and alkaline phosphatase. Marker genes of three germ layers were expressed from embryoid bodies of both cell lines. Conclusion: This study suggests that mouse ES cells could be established from isolated blastomeres, although the efficiency is lower than whole embryos. This animal model could be applied to establishment of autologous human ES cells from biopsied blastomeres of preimplantation embryos in human IVF-ET program.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.16-27
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• 2011

Embryo is a very early stage of the development of multicellular organism such as animals and plants. It is an important research target for studying ontogeny because the fundamental body system of multicellular organism is determined during an embryo state. Researchers in the developmental biology have a large volume of embryo image databases for studying embryos and they frequently search for an embryo image efficiently from those databases. Thus, it is crucial to organize databases for their efficient search. Hierarchical clustering methods have been widely used for database organization. However, most of previous algorithms tend to produce a highly skewed tree as a result of clustering because they do not simultaneously consider both the size of a cluster and the number of objects within the cluster. The skewed tree requires much time to be traversed in users' search process. In this paper, we propose a method that effectively organizes a large volume of embryo image data in a balanced tree structure. We first represent embryo image data as a similarity-based graph. Next, we identify clusters by performing a graph partitioning algorithm repeatedly. We check constantly the size of a cluster and the number of objects, and partition clusters whose size is too large or whose number of objects is too high, which prevents clusters from growing too large or having too many objects. We show the superiority of the proposed method by extensive experiments. Moreover, we implement the visualization tool to help users quickly and easily navigate the embryo image database.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.293-300
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• 2009

The rate of fetus with abnormal chromosomes increase with maternal age. Nondisjunction of aging oocyte chromosome is a major reason for the increased rate of abnormalities. Telomeres are the ends of eukaryotic chromosome, which are essential for chromosome stability and are related in cell senescence. This study was carried out to analyze the chromosome aberration rate and amount of telomeric DNA in chick embryo along with maternal age. Fertilized eggs and blood were sampled from White Leghorn layers starting at 20 weeks through to 70 weeks age at 10 weeks interval. Chromosome aberration rate was analyzed by karyotyping. The amounts of telomeric DNA in embryonic cells and lymphocytes were quantified by Quantitative Fluorescence in situ Hybridization method. The chromosome aberration rate in chick embryos significantly differed with maternal age. The chromosome aberration rate increased at early laying period and beyond 70 weeks of maternal age. Therefore, chromosome aberration rate was affected by maternal age due to ovulated oocytes state. However, the amount of telomeric DNA on embryonic cells did not differ significantly with maternal age. Thus, maternal age does not affects telomere quantity in their embryos due to cellular reprograming at early embryonic stage after fertilization.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.2
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• pp.117-124
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• 2007

Objective: The aim of this study was to compare the efficacy of slow freezing with vitrification method for cryopreservation of mouse pronuclear stage embryos. Methods: Mouse pronuclear embryos obtained from superovulated mice and classified into 2 groups of slow freezing and vitrification. Slow freezing solution consisted of 1.5 M PROH, 0.1 M sucrose, while vitrification solution consisted of 40% ethylene glycol, 18% Ficoll and 0.5 M sucrose diluted in Dulbecco's phosphate-buffered saline supplemented with 10% SSS. Recovery and survival rates after thawing and development rates to hatching balstocyst stage were compared between two groups. Results: After freezing and thawing, recovery rate of slow freezing group was 93.8%, whereas vitrification group was 66.5% (p<0.01). Survival rate of recovered embryos were similar between two groups as 83.2% in slow freezing and 87.6% in vitrification. Embryo development rates to 2-cell stage after 24 hrs (77.0% vs 59.1%), 4-cell after 48 hrs (72.6% vs 53.3%), blastocyst after 96 hrs (53.1% vs 40.1%) of thawing were significantly higher in vitrification group than those of slow freezing group, respectively. Conclusion: The vitrification method may provide better developmental competence of frozen-thawed embryos than that of slow freezing method for cryopreservation of mouse pronuclear stage embryos.

• Applied Microscopy
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• v.42 no.2
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• pp.77-86
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• 2012

The morphological and histologic differentiation of the central nervous system (CNS) in the wolf spider Arctosa kwangreungensis with respect to postembryonic development are studied using light and scanning electron microscopes. The organization of CNS which consisted of supraesophageal ganglion (SpG) and subesophageal ganglion (SbG) are established prior to the postembryo stage. The brain of first instar spiderling after a molt of the postembryo is also made up of supraesophageal ganglion and subesophageal ganglion. Although development of the optic nerve and optic lobe in SpG are not completed during the postembryoic stage, completion of whole neural system resemble to that of adult are established during the second instar stage. In particular, optic gangalion is developed from the undifferentiated cell clusters of the SpG, moreover four pairs of appendage ganglia and another pairs of abdominal ganglia are produced from the SbG. Nerve cells of the most developing stages are composed of typical monopolar neur1ons, and total three types of neurons can be identified through the histological and morphological basis of present study. These cell clusters are differentiated into neurons and grow dendritic fibers according to further development of the CNS.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.14-20
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• 2014

This study is aimed to search the possibility of developmental toxicity test using the zebrafish from the pesticide. We selected herbicides alachlor and butachlor, reported for fish toxicity, and insecticide fipronil reported for the high fish toxicity and the honey bee risk among the pesticides with high usability for the examples of the pesticides in this experiment. In this study, we showed those effects on the zebrafish embryo development by exposing different kinds of pesticide with different concentration and exposed time periods. As a result, the rates of hatching and abnormality of the zebrafish embryo after treatments of alachlor were increased in 24-48 hpf group, and the juvenile fishes in every group exposed to $40{\mu}M$ or more of alachlor displayed sever morphological changes such as bent tails, edema and activity failures. In case of the butachlor, the rates of hatching and the abnormality in 24-48 hpf group were higher than the other groups exposed in different time periods. The fatality before hatching was high in $40{\mu}M$ or more of butachlor treatment, and entire zebrafish embryos in 48 hpf group died before hatching. All the living juvenile fishes showed morphological changes as like as the treatment of alachlor. The rate of hatching and the survival of the zebrafish embryo by the fipronil were higher than other pesticides. However, morphological changes such as bent tails were observed from the most of living juvenile fishes. Therefore, the effects of three different pesticides with different concentrations and exposing time periods on the development of zebrafish embryos showed that all the pesticides effects were proportional to the concentration, and exposing time periods may cause the morphological abnormality.

• Development and Reproduction
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• v.3 no.1
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• pp.59-67
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• 1999

To investigate the role of interleukin-l$\beta$ (IL-1$\beta$) in the embryonic development, in vivo and in vitro expression patterns of IL-1$\beta$ gene in the preimplantation mouse embryos were examined by RT-PCR, and the effects of explanted mouse ovi-duct and uterine epithelial cells on the expression of IL-1$\beta$ gene in the pleimplantation mouse embryos were examined by co-culture. IL-1$\beta$ mRNA was detected in the embryos from 4-cell stage to blastocyst stage in vivo and from morula stage to hatching blastocyst stage in vitro. This transcript was not detected from the GV stage to late 2-cell stage in vivo, and not at the 4-cell and 8-cell stages in vitro. For the co-culture of late 2-cell embryos with the explanted mouse oviduct and uterine epithelial cells, oviducts and uterine epithelial cells were isolated at 48 hour alter the hCG injection. The explanted oviduct and uterine epithelial cells in co-culture groups facilitated the IL-1$\beta$ gene expression of the mouse embryos in comparison with the control. Taken together these results suggest that the presence of IL-1$\beta$ plays an important role in preimplantation embryonic development. In addition, the up-regulation of IL-1$\beta$ gene expression by the explanted oviduct and uterine epithelial cells demonstrates that embryonic expression of IL-l$\beta$ gene may be regulated by the interaction with oviductal and uterine factor (s).

• Development and Reproduction
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• v.4 no.1
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• pp.45-52
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• 2000

Membrane type matrix metalloproteinases(MT-MMPs) have been suggested to play an important role during structural remodeling of various tissue. Expression patterns of MT1-MMP and MT2-MMP mRNAs were investigated in oocytes, embryos, ovary and oviduct of mouse during their differentiation or periovulatory period using RT-PCR technique. Both cDNA products of MT1- and MT2-MMP of immature oocytes were barely discernable with a minimum amount but the expressions were distinct in mature oocytes regardless that they were matured in vivo or in vitro. MT2-MMP was not expressed by 2-cell embryos but was expressed by 4-cell stage embryos. From the morula stage untill hatched blastocyst stage, embyos showed intesnse expression of MT2-MMP with a sudden increase at blastocyst stage. While mouse ovarian tissues showed both expression of MT1- and MT2-MMP, there was no stage-specific difference throughout the estrous cycle. Mouse oviducts also exhibit constant amount of both MT1- and MT2-MMP expressions throughout periovulatory period, i.e., before or after ovulation. These observations lead to suggest that the differential expressions of maternal MT1- and MT2-MMP during meiotic resumption of mouse oocytes and embryonic expression of MT2-MMP particularly at blastocyst stage might play a role in the differentiation of mouse oocytes and／or embryos. The precise function of MT1- and MT2-MMP with regards to their participation in the remodeling of ovarian and oviductal tissues remains in a question.