• Reproductive and Developmental Biology
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• v.33 no.3
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• pp.133-137
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• 2009

Pluripotent embryonic stem (ES) cells isolated from inner cell mass (ICM) of blastocyst-stage embryos are capable of differentiating into various cell lineages and demonstrate germ-line transmission in experimentally produced chimeras. These cells have a great potential as tools for transgenic animal production, screening of newly-developed drugs, and cell therapy. Miniature pigs, selectively bred pigs for small size, offer several advantages over large breed pigs in biomedical research including human disease model and xenotransplantation. In the present study, factors affecting primary culture of somatic cell nuclear transfer blastocysts from miniature pigs for isolation of ES cells were investigated. Formation of primary colonies occurred only on STO cells in human ES medium. In contrast, no ICM outgrowth was observed on mouse embryonic fibroblasts (MEF) in porcine ES medium. Plating intact blastocysts and isolated ICM resulted in comparable attachment on feeder layer and primary colony formation. After subculture of ES-like colonies, two putative ES cell lines were isolated. Colonies of putative ES cells morphologically resembled murine ES cells. These cells were maintained in culture up to three passages, but lost by spontaneous differentiation. The present study demonstrates factors involved in the early stage of nuclear transfer ES cell isolation in miniature pigs. However, long-term maintenance and characterization of nuclear transfer ES cells in miniature pigs are remained to be done in further studies.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.1-12
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• 2002

The periodontal ligament(PDL) is a unique tissue that is crucial for tooth function. However, little is known of the molecular mechanisms controlling PDL function. PDL-specific protein;PDLs22 had been previously identified as a novel protein isolated from cultured human PDL fibroblasts using subtraction hybridization between human gingival fibroblasts and PDL fibroblasts. The aim of this study was to examine the expression pattern and tissue localization of PDLs22 protein in embryonic and various postnatal stages of developing mouse using immunohistochemical staining. Embryos (E18) and postnatal (P1, P4, P5, P15, P18) were decapitated and the heads were fixed overnight in a freshly prepared solution of 4% paraformaldehyde. Some specimens were decalcified for $2{\sim}4$ weeks in a solution containing 10% of the disodium salt of ethylenediamine-tetraacetic acid (EDTA). Next, tissues were dehydrated, embedded in paraffin and sectioned serially at $6{\mu}m$ in thickness. Polyclonal antiserum raised against PDLs22 peptides, ISNKYLVKRQSRD, were made. The localization of PDLs22 in tissues was detected by polyclonal antibody against PDLs22 by means of immunohistochemical staining. The results were as follows; 1. Expression of PDLs22 protein was not detected in the tooth germ of bud and cap stage. 2. At the late bell stage and root formation stage, strong expression of PDLs22 protein was observed in developing tooth follicle, osteoblast-like cells, and subodontoblastic cells in the tooth pulp, but not in gingival fibroblasts, ameloblasts and odontoblasts of tooth germ 3. In erupted tooth, PDLs22 protein was intensely expressed in PDL and osteoblast-like cells of alveolar bone, but not in gingival fibroblasts, mature osteocytes and adjacent salivary glands. 4. In the developing alveolar bone and mid-palatal suture, expression of PDLs22 protein was seen in undifferentiated mesenchymal cells and osteoblast-like cells of developing mid-palatal suture, but not in mature osteocytes and chondrocytes. These results suggest that PDLs22 protein may play an important role in the differentiation of undifferentiated mesenchymal cells in the bone marrow and PDL cells, which can differentiate into multiple cell types including osteoblasts, cementoblasts, and PDL fibroblasts. However, more researches should be performed to gain a better understanding of the exact function of PDLs22 protein which related to the PDL cell differentiation.

• The Korean Journal of Food & Health Convergence
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• v.4 no.4
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• pp.18-25
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• 2018

Proteins play a key role in many functions such as metabolic activity, differentiation, as cargos and cell fate regulators. It is necessary to know about the markers involved in male fertility in order to develop remedies for the treatment of male infertility. But, the role of the proteins is not limited to particular function in the biological systems. Some of the proteins act as ion channels such as catsper and proteins like Nanos acts as a translational repressor in germ cells and expressed in prenatal period whose role in male fertility is uncertain. Rbm5 is a pre mRNA splicing factor necessary for sperm differentiation whose loss of function results deficit in sperm production. DEFB114 is a beta defensin family protein necessary for sperm motility in LPS challenged mice where as TEX 101 is a plasma membrane specific germ cell protein whose function is not clearly known u to now. Gpr56 is another adhesion protein whose null mutation leads to arrest of production of pups in rats. Amyloid precursor protein role in Alzheimer's disease is already known but it plays an important role in male fertility also but its function is uncertain and has to be considered while targeting APP during the treatment of Alzheimer's disease. The study on amyloid precursor protein in male fertility is a novel thing but requires further study in correlation to alzheimer's disease.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.546.2-546
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• 2003

Dental follicle is the mesenchymal tissue which surrounds developing tooth germ. During tooth root development, periodontal components such as cementum, periodontal ligament and alveolar bone are considered to be created by progenitors present in the dental follicle. However, little is known about these progenitors. Previously we observed that cultured bovine dental follicle cells (BDFC) contained putative cementoblast progenitors. To further analyze the biology of these cells, we have attempted to immortalize BDFC by expression of the polycomb group protein Bmi-1 and human telomerase reverse transcriptase (hTERT). The BDFC expressing Bmi-1 and hTERT showed extended life span by 90 population doublings more than normal BDFC, and still contained cells with potential to differentiate into cementoblasts upon implantation into immunodeficiency mice. Among them, we established a clonal cell line designated as BCPb8, which formed cemetum-like mineralized tissue reactive to anti-cementum specific monoclonal antibody, 3G9, and expressed mRNA for bone sialoprotein, osteocalcin, osteopontin and type I collagen upon implantation. Thus with the combination of hTERT and Bmi-1, we succeeded in immortalization of cementoblast progenitor in BDFC without affecting differentiation potential. The BCPb8 progenitor cell line could be a useful tool not only to study cementogenesis but also to develop regeneration therapy for periodontitis.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.72-74
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• 2005

In this paper, we propose an adaptive PID controller using a cell-mediated immune response to improve a PID control performance. The proposed controller is based on the specific immune response of the biological immune system that is cell-mediated immunity. The immune system of organisms in the real body regulates the antibody and the T-cells to protect an attack from the foreign materials like virus, germ cells, and other antigens. It has similar characteristics that are the adaptation and robustness to overcome disturbances and to control the plant of engineering application. We first build a model of the T-cell regulated immune response mechanism and then designed an I-PID controller focusing on the T-cell regulated immune response of the biological immune system. We apply the proposed methodology to building structures to mitigate vibrations due to strong winds for evaluation of control performances. Through computer simulations, system responses are illustrated and additionally compared to traditional control approaches.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.377-386
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• 2011

The ultrastructures of germ cells during spermatogenesis and sperm morphology in male Mya arenaria oonogai, which was collected on the coastal waters of Samcheonpo, south coast of Korea, were investigated by transmission electron microscopic observations. In the early stage of the spermatid during spermiogenesis, a few granules and a proacrosomal granule, which is formed by the Golgi complex, appear on the spermatid nucleus, and then it becomes a proacrosomal vesicle. Consequently, it becomes an acrosome by way of the process of acrosome formation. The morphologies of the sperm nucleus type and the acrosome of this species have a curved cylindrical type and cone shape, respectively. The spermatozoon is approximately $48-50{\mu}m$ in length including a curved cylinderical sperm nucleus (about $2.65{\mu}m$ long), an acrosome (about $0.64{\mu}m$ in length) and tail flagellum ($40-45{\mu}m$ long). As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part (region), while the apex part of the acrosome shows electron lucent part (region). These charateristics of the sperm belong to the family Myidae or some species of Veneridae in the subclass Heterodonta, unlike a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part (region). Therefore, it is easy to distinguish the families or the subclasses by the acrosome structures. Exceptionally, In particular, a cylinder-like nucleus of the sperm is curved (the angle of the nucleus is about $20^{\circ}$), as seen in some species of Veneridae (range from $0^{\circ}-80^{\circ}$). The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appeared in most species except for a few species in Veneridae in the subclass Heterodonta. Cross-sectioned axoneme of the sperm tail flagellum shows a 9+2 structure: the axoneme of the sperm tail flagellum consists of nine pairs of peripheral microtubules at the periphery and a pair of central doublets at the center.

• Development and Reproduction
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• v.14 no.3
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• pp.155-162
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• 2010

The trophectoderm is one of the earliest cell types to differentiate in the forming placenta. It is an important for the initial implantation and placentation during pregnancy. Trophoblast stem cells (TBSCs) develop from the blastocyst and are maintained by signals emanating from the inner cell mass. However, several limitations including rarity and difficulty in isolation of trophoblast stem cells derived from blastocyst still exist. To establish a model for trophoblast differentiation, we isolated TBSCs from human term placenta ($\geq$38 weeks) and characterized. Cell cycle was analyzed by measuring DNA content by FACS analysis and phenotype of TBSCs was characterized by RT-PCR and FACS analysis. TBSCs have expressed various markers such as self-renewal markers (Nanog, Sox2), three germ layer markers (hNF68, alpha-cardiac actin, hAFP), trophoblast specific markers (CDX-2, CK7, HLA-G), and TERT gene. In FACS analysis, TBSCs isolated from term placenta showed that the majority of cells expressed CD13, CD44, CD90, CD95, CD105, HLA-ABC, cytokeratin 7, and HLA-G. Testing for CD31, CD34, CD45, CD71, vimentin and HLA-DR were negative. TBSCs were shown to decrease the growth rate when cultured in conditioned medium without FGF4/heparin as well as the morphology was changed to a characteristic giant cell with a large cytoplasm and nucleus. In invasion assay, TBSCs isolated from term placenta showed invasion activities in in vivo using nude mice and in vitro Matrigel system. Taken together, these results support that an isolation potential of TBSCs from term placenta as well as a good source for understanding of the infertility mechanism.

• Development and Reproduction
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• v.19 no.1
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• pp.1-10
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• 2015

The purpose of the present study was to examine the seminiferous epithelium cycle of Bombina orientalis using a light microscope. The cycle was divided into a total of 10 stages, according to the morphological characteristics of the cells. The spermatogenetic cells included primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatid and sperm. At stage I, the primary spermatogonia was located closer to basal lamina of the seminiferous tubule without spermatocyst formations. Especially at the stage II, the secondary spermatogonia were located in the spermatocyst. The primary and secondary spermatocytes were found from stages III to VI. The secondary spermatocytes were smaller in size than the primary spermatocytes, but they had thicker nucleoplasm and smaller nuclei. The round-shaped, early sperm cells were formed in stage VII, and further divided at stage VIII to have more concentrated nucleoplasm before division to matured sperm cells. At stage X, the matured sperm cells emerged from the spermatocyst. Considering the above results, this study presented the special characteristics in the generation and type of sperm formation. The germ cell formation occurred in various stages, like the perspectives of Franca et al (1999), ultimately, providing taxonomically useful information.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.423-428
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• 2000

In 1997 when cloned sheep Dolly and soon after Polly were born, it had become head-line news because in the former the nucleus that gave rise to the lamb came from cells of six-year-old adult sheep and in the latter case a foreign gene was inserted into the donor nucleus to make the cloned sheep produce human protein, factor IX, in e milk. In the last few years, once the realm of science fiction, cloned mammals especially in livestock have become almost commonplace. What the press accounts often fail to convey, however, is that behind every success lie hundreds of failures. Many of the nuclear-transferred egg cells fail to undergo normal cell divisions. Even when an embryo does successfully implant in the womb, pregnancy often ends in miscarriage. A significant fraction of the animals that are born die shortly after birth and some of those that survived have serious developmental abnormalities. Efficiency remains at less than one % out of some hundred attempts to clone an animal. These facts show that something is fundamentally wrong and enormous hurdles must be overcome before cloning becomes practical. Cloning researchers now tent to put aside their effort to create live animals in order to probe the fundamental questions on cell biology including stem cells, the questions of whether the hereditary material in the nucleus of each cell remains intact throughout development, and how transferred nucleus is reprogrammed exactly like the zygotic nucleus. Stem cells are defined as those cells which can divide to produce a daughter cell like themselves (self-renewal) as well as a daughter cell that will give rise to specific differentiated cells (cell-differentiation). Multicellular organisms are formed from a single totipotent stem cell commonly called fertilized egg or zygote. As this cell and its progeny undergo cell divisions the potency of the stem cells in each tissue and organ become gradually restricted in the order of totipotent, pluripotent, and multipotent. The differentiation potential of multipotent stem cells in each tissue has been thought to be limited to cell lineages present in the organ from which they were derived. Recent studies, however, revealed that multipotent stem cells derived from adult tissues have much wider differentiation potential than was previously thought. These cells can differentiate into developmentally unrelated cell types, such as nerve stem cell into blood cells or muscle stem cell into brain cells. Neural stem cells isolated from the adult forebrain were recently shown to be capable of repopulating the hematopoietic system and produce blood cells in irradiated condition. In plants although the term$\boxDr$ stem cell$\boxUl$is not used, some cells in the second layer of tunica at the apical meristem of shoot, some nucellar cells surrounding the embryo sac, and initial cells of adventive buds are considered to be equivalent to the totipotent stem cells of mammals. The telomere ends of linear eukaryotic chromosomes cannot be replicated because the RNA primer at the end of a completed lagging strand cannot be replaced with DNA, causing 5' end gap. A chromosome would be shortened by the length of RNA primer with every cycle of DNA replication and cell division. Essential genes located near the ends of chromosomes would inevitably be deleted by end-shortening, thereby killing the descendants of the original cells. Telomeric DNA has an unusual sequence consisting of up to 1,000 or more tandem repeat of a simple sequence. For example, chromosome of mammal including human has the repeating telomeric sequence of TTAGGG and that of higher plant is TTTAGGG. This non-genic tandem repeat prevents the death of cell despite the continued shortening of chromosome length. In contrast with the somatic cells germ line cells have the mechanism to fill-up the 5' end gap of telomere, thus maintaining the original length of chromosome. Cem line cells exhibit active enzyme telomerase which functions to maintain the stable length of telomere. Some of the cloned animals are reported prematurely getting old. It has to be ascertained whether the multipotent stem cells in the tissues of adult mammals have the original telomeres or shortened telomeres.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5705-5711
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• 2013

Background: Embryonic stem cells (ESCs) have the potential to form teratomas when implanted into immunodeficient mice, but data in immunocompetent mice are limited. We therefore investigated teratoma formation after implantation of three different mouse ESC (mESC) lines into immunocompetent mice. Materials and Methods: BALB/c mice were injected with three highly germline competent mESCs (129Sv, BALB/c and C57BL/6) subcutaneously or under the kidney capsule. After 4 weeks, mice were euthanized and examined histologically for teratoma development. The incidence, size and composition of teratomas were compared using Pearson Chi-square, t-test for dependent variables, one-way analysis of variance and the nonparametric Kruskal-Wallis analysis of variance and median test. Results: Teratomas developed from all three cell lines. The incidence of formation was significantly higher under the kidney capsule compared to subcutaneous site and occurred in both allogeneic and syngeneic mice. Overall, the size of teratoma was largest with the 129Sv cell line and under the kidney capsule. Diverse embryonic stem cell-derived tissues, belonging to the three embryonic germ layers, were encountered, reflecting the pluripotency of embryonic stem cells. Most commonly represented tissues were nervous tissue, keratinizing stratified squamous epithelium (ectoderm), smooth muscle, striated muscle, cartilage, bone (mesoderm), and glandular tissue in the form of gut- and respiratory-like epithelia (endoderm). Conclusions: ESCs can form teratomas in immunocompetent mice and, therefore, removal of undifferentiated ESC is a pre-requisite for a safe use of ESC in cell-based therapies. In addition the genetic relationship of the origin of the cell lines to the ability to transplant plays a major role.