• Journal of Animal Reproduction and Biotechnology
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• v.38 no.1
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• pp.26-31
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• 2023

Chicken embryonic stem (ES) cells have great potential and provide a powerful tool to investigate embryonic development and to manipulate genetic modification in a genome. However, very limited studies are available on the functional characterization and robust expansion of chicken ES cells compared to other species. Here, we have developed a method to generate chicken embryonic stem cell-like cells under pluripotent culture conditions. The chicken embryonic stem cell-like cells were cultivated long-term over several passages of culture without loss of pluripotency in vitro and had the specific expression of key stem cell markers. Furthermore, they showed severe changes in morphology and a significant reduction in pluripotent genes after siRNA-mediated NANOG knockdown. Collectively, these results demonstrate the efficient generation of chicken embryonic stem cell-like cells from EGK stage X blastoderm-derived singularized cells and will facilitate their potential use for various purposes, such as biobanking genetic materials and understanding stemness in the fields of animal biotechnology.

• ALGAE
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• v.27 no.4
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• pp.225-234
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• 2012

Zygnema is a conjugating filamentous green algal genus that is distributed in a broad range of freshwater habitats, from sea level to alpine summits. Although more than 150 species have been described worldwide, their taxonomy remains unclear, probably owing to their relatively simple morphology. We investigated the detailed morphology of Korean Zygnema species, combined with analysis of the plastid psbA gene from 22 specimens of the genus and putative relatives, in order to develope a key to their identification and isolation, and to determine their relationships. We recognized two species of Zygnema; Z. insigne and Z. leiospermum, based on morphological characters such as width of the vegetative cell, position of zygospores, dimensions and form of spores, shape of female gametangia, and color of mesospores. The analysis of psbA data was consistent with morphological comparison. The pairwise divergence between two species was 3.7-4.1% (34-38 bp) in psbA sequences. The phylogeny of psbA revealed the monophyly of Z. insigne and Z. leiospermum together with two isolates of Z. circumcarinatum from Germany and Scotland. This is the first report on the psbA gene phylogeny of Zygnema.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.135-149
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• 1999

This study was concerned with assessment of dietynitrosamine (DEN) induced liver cell carcinogenesis by measurement of changes preceding the development of neoplasms. The changes of hepatic morphology in rats(Sprague-Dawley) were detected by hematoxylin-eosin stain and immunohistochemistry(PCNA). The results were as follows ; 1. Minor behavioral change, brittleness of hair and decreased amount of water and diet intake. were observed in rats 7 weeks after DEN administration. 2. Variable size of liver tumor and hepatomegaly were observed in rats treated with DEN after 10 weeks. 3. Numerous vacuoles were showed on the midzonal and or peripheral areas of hepatic lobules. The large and polymorphological hepatocytes with eosinophilic cytoplasm or densely basophilic mitotic nucleoli were showed. 4. Several proliferative small round cells were shown on vacuolated and necrotic areas in peripheral hepatic lobules or portal areas. 5. PCNA-positive cells were showed on the vacuolated portal areas and peripheral areas of hepatic lobules. Maximal positivity was 23.6% in the areas of small round cells. In conclusion, this result confirmed that the DEN was one of the potent hepatocarcinogens. In histopathological analysis, the altered foci, hyperplastic nodules, neoplastic nodules, adenomas and carcinomas were observed in liver tumors induced by administration of DEN in rats.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.1-13
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• 1995

Chlorhexidine and Listerine are widely used in dentistry due to its effectiveness on plaque control and bactericidal action. The effects of these agent on chronic gingivitis and wound healing following surgical periodontal therapy in human has been favorable. Understanding the effects of chlorhexidine and Listerine on human gingival fibroblast will provide the rationale for its use during the healing process of periodontal surgery. The purpose of this study was to compare the effects of chlorhexidine and Listerine on human gingival fibroblast. Human gingival fibroblasts were cultured from the healthy gingiva on the extracted premolar of orthodontic patients. Human gingival fibroblast were trypsinized and cultured in growth medium added range of 0.0012-0.12% chlorhexidine and 1-100% Listerine mouth wash solution. The cell used in this study were between fifth to eighth passage number. The cell morphology were examined by inverted microscope and the cell activity were measured by MIT assay. The Morphology of gingival fibroblast added Chlorhexidine and Listerine at the concentration of all range were became globular and lost their cytoplasmic process. Our results indicate that a 0.0012 concentration of chlorhexidine and 1% concentration of Listerine were shows minimal cytotoxicity, but above these concentraion, there was a significant difference between the cell activity in the experimental group and control group(p

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.125-128
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• 1998

Electroluminescent(EL) devices based on organic thin films have attracted lots of interests in large-area light-emitting display. One of the problems of such device is a lifetime, where a degradation of the cell is possibly due to an organic layer's thickness, morphology and interface with electrode. In this study, light-emitting organic electroluminescent devices were fabricated using Alq$_3$(8-hydroxyquinolinate aluminum) and TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1-1'-biphenyl]-4,4'-diamine).Where Alq$_3$ is an electron-transport and emissive layer, TPD is a hole-transport layer. The cell structure is ITO/TPD/Alq$_3$/Al and the cell is fabricated by vacuum evaporation method. In a measurement of current-voltage characteristics, we obtained a turn-on voltage at about 9 V. And we used other buffer layer of PPy(Polypyrrole) with ITO/PPy/TPD/Alq$_3$/Al structure. We observed a surface morphology by AFM(Atomic Force Microscopy), UV/visible absorption spectrum, and PL(Photoluminescence) spectrum. We obtained the UV/visible absorption peak at 358nm in TPD and at 359nm in Alq$_3$, and at 225nm and the PL peaks at 410nm in TPD and at 510nm in Alq$_3$ and at 350nm. We also studied EL spectrum in the cell structure of ITO/TPD/Alq$_3$/Al and ITO/PPy/TPD/Alq$_3$/Al and we observed the EL spectrum peak at 510nm from our cell

• Korean Journal of Ichthyology
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• v.20 no.2
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• pp.90-96
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• 2008

The histological morphology on the skin of Misgurnus anguillicaudatus was described in the three regions such as dorsal, lateral, occiput and subsequently morphological variations of the skin were monthly observed for a year. The skin consisted of epidermis having epithelial cell, club cell and mucus cell, and dermis of mainly connective tissue fiber, embedded scale and blood capillary. Unicellular mucus cells situated at the epidermis underwent seasonal change in its size, as well as number and amounts of mucus-secreting materials, which they greatly increased in winter, but did not in summer. As it is getting cold, the mucus cells' shape changed from initial spherical to oval or elongated form. Such considerable changes in the mucus cell were particularly most evident in the occiput during winter. Moreover, the dermis largely thickened about 2~3 times in winter than in summer. Based on these results, we discussed function for the mucus on what it mainly acts in nature and information on whether mucus cells' seasonal variations affect on hibernation and cutaneous respiration.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.492-499
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• 2009

A Silkie Bantam embryo fibroblast line (named SBF59 line) was successfully established by using direct explant culture and cryopreservation techniques. Cell morphology, viability, dynamic growth and contamination were tested and the karyotype and levels of isoenzymes of lactic dehydrogenase and malic dehydrogenase were analyzed. Four kinds of fluorescent protein extrogenes, including $pEGFP-N_3$, $pECFP-N_1$, $pEYFP-N_1$ and $pDsRed1-N_1$ were transfected into the cells. The results showed that the cells were healthy and possessed a fibrous structure without a change in morphology. The average viability of the cells was 96% before freezing and 90.5% after thawing. The growth curve appeared as typical "S" shape and the cell growth passed through a detention phase, a logarithmic phase and a platform phase; the estimated population doubling time (PDT) was 38.5 h; assays for the presence of bacteria, fungi, viruses and mycoplasmas were negative; the cell line showed no cross contamination when assessed by isoenzyme analysis; the chromosome number was 2n = 78 on more than 88% of occasions; four kinds of fluorescent protein extro-genes appeared to be expressed effectively with a high transfection efficiency between 18.3% and 42.3%. The cell line met the required quality control standard. It not only preserves the genetic resources of the important Silkie Bantam at the cellular level but also provides valuable materials for genomic, post-genomic, somatic cell cloning research and other applications.

• Korean Journal of Materials Research
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• v.23 no.11
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• pp.655-660
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• 2013

Photoelectrochemical cells have been used in photolysis of water to generate hydrogen as a clean energy source. A high efficiency electrode for photoelectrochemical cell systems was realized using a ZnO hierarchical nanostructure. A ZnO nanofiber mat structure was fabricated by electrospinning of Zn solution on the substrate, followed by oxidation; on this substrate, hydrothermal synthesis of ZnO nanorods on the ZnO nanofibers was carried out to form a ZnO hierarchical structure. The thickness of the nanofiber mat and the thermal annealing temperature were determined as the parameters for optimization. The morphology of the structures was examined by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The performance of the ZnO nanofiber mat and the potential of the ZnO hierarchical structures as photoelectrochemical cell electrodes were evaluated by measurement of the photoelectron conversion efficiencies under UV light. The highest photoconversion efficiency observed was 63 % with a ZnO hierarchical structure annealed at $400^{\circ}C$ in air. The morphology and the crystalline quality of the electrode materials greatly influenced the electrode performance. Therefore, the combination of the two fabrication methods, electrospinning and hydrothermal synthesis, was successfully applied to fabricate a high performance photoelectrochemical cell electrode.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.7-12
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• 2004

This study was performed to establish the effective culture condition for the establishment of clonal lines from porcine fetal fibroblast cells. Fibroblasts derived from a pig fetus (Day 50) were cultured and passaged two times before use. A single cell was seeded in 96-well plates, cultured in medium supplemented with different concentrations of FBS, catalase or $\beta$-mercaptoethanol ($\beta$ME), and classified by cell size and morphology. Cells were passaged two times into 4-well dish before freezing. The establishment efficiencies were not different among different concentrations of FBS (0.3 to 5.1%). However, population doubling time (PDT) was significantly decreased by increasing the FBS concentration (P＜0.05). The establishment efficiency of $\beta$ME-added group (10.4%) was significantly higher than those of catalase-added and control groups (3.5%, and 3.5%, respectively, p＜0.05), and PDT was significantly decreased (23.6 vs 28.1, and 25.5 h, respectively, p＜0.05). However, catalase did not show a positive effect on the establishment efficiency. Cell size and morphology did not affect the establishment efficiency and PDT of clonal lines. The result of present study shows that the establishment efficiency of clonal cell lines can be enhanced by the culture in media supplemented with 30% FBS and $\beta$ME.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.6
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• pp.423-429
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• 2012

Brain ischemia leads to overstimulation of N-methyl-D-aspartate (NMDA) receptors, referred as excitotoxicity, which mediates neuronal cell death. However, less attention has been paid to changes in synaptic activity and morphology that could have an important impact on cell function and survival following ischemic insult. In this study, we investigated the effects of reperfusion after oxygen/glucose deprivation (OGD) not only upon neuronal cell death, but also on ultrastructural and biochemical characteristics of postsynaptic density (PSD) protein, in the stratum lucidum of the CA3 area in organotypic hippocampal slice cultures. After OGD/reperfusion, neurons were found to be damaged; the organelles such as mitochondria, endoplasmic reticulum, dendrites, and synaptic terminals were swollen; and the PSD became thicker and irregular. Ethanolic phosphotungstic acid staining showed that the density of PSD was significantly decreased, and the thickness and length of the PSD were significantly increased in the OGD/reperfusion group compared to the control. The levels of PSD proteins, including PSD-95, NMDA receptor 1, NMDA receptor 2B, and calcium/calmodulin-dependent protein kinase II, were significantly decreased following OGD/reperfusion. These results suggest that OGD/reperfusion induces significant modifications to PSDs in the CA3 area of organotypic hippocampal slice cultures, both morphologically and biochemically, and this may contribute to neuronal cell death and synaptic dysfunction after OGD/reperfusion.