• Journal of Animal Reproduction and Biotechnology
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• v.39 no.1
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• pp.19-30
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• 2024

Background: Although an understanding of the proliferation and differentiation of fish female germline stem cells (GSCs) is very important, an appropriate threedimensional (3D) research model to study them is not well established. As a part of the development of stable 3D culture system for fish female GSCs, we conducted this study to establish a 3D aggregate culture system of ovarian cells in marine medaka, Oryzias dancena. Methods: Ovarian cells were separated by Percoll density gradient centrifugation and two different cell populations were cultured in suspension to form ovarian cell aggregates to find suitable cell populations for its formation. Ovarian cell aggregates formed from different cell populations were evaluated by histology and gene expression analyses. To evaluate the media supplements, ovarian cell aggregate culture was performed under different media conditions, and the morphology, viability, size, gene expression, histology, and E2 secretion of ovarian cell aggregates were analyzed. Results: Ovarian cell aggregates were able to be formed well under specific culture conditions that used ultra-low attachment 96 well plate, complete mESM2, and the cell populations from top to 50% layers after separation of ovarian cells. Moreover, they were able to maintain minimal ovarian function such as germ cell maintenance and E2 synthesis for a short period. Conclusions: We established basic conditions for the culture of O. dancena ovarian cell aggregates. Additional efforts will be required to further optimize the culture conditions so that the ovarian cell aggregates can retain the improved ovarian functions for a longer period of time.

• IMMUNE NETWORK
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• v.9 no.4
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• pp.133-137
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• 2009

We have recently shown that activin A, a member of TGF-$\beta$ superfamily, stimulates mouse B cells to express IgA isotype but other isotypes. In the present study, we further characterized effects of activin A on B cell growth and IgA expression. We found that activin A did not have effect on LPS-stimulated cell viability. In parallel, CFSE staining analysis revealed that activin A did not alter cell division. An increase of IgA secretion by activin A was completely abrogated by anti-activin A Ab but not by anti-TGF$\beta$1 Ab. In the same conditions, no other isotypes are significantly affected by each antibody treatment. Finally, activin A, as similar to TGF-$\beta$1, increased IgA secretion by mesenteric lymph node cells. These results suggest that activin A can specifically stimulate IgA response, independent of TGF-$\beta$ in the gut.

• Transactions on Electrical and Electronic Materials
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• v.10 no.4
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• pp.143-145
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• 2009

The electrical and photovoltaic properties of single junction silicon quantum dot solar cells are investigated. A prototype solar cell with an effective area of 4.7 $mm^2$ showed an open circuit voltage of 394 mV and short circuit current density of 0.062 $mA/cm^2$. A diode model with series and shunt resistances has been applied to characterize the dark current-voltage data. The photocurrent of the quantum-dot solar cell was found to be strongly dependent on the applied voltage bias, which can be understood by consideration of the conduction mechanism of the activated carriers in the quantum dot imbedded material.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.24-29
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• 2017

A fluorinated polybenzimidazole (FPBI) was synthesized from 3,3-diaminobenzidine (DAB) of tetraamine, 2,2-bis(4-carboxyphenyl)hexafluoropropane of aromatic biscarboxylic acid, and 4,4-sulfonyldibenzoic acid of aromatic biscarboxylic acid in polyphosphoric acid (PPA). A FPBI was easily cast and made into clear films. The structure of condensation polymers and corresponding membranes were analyzed using GPC (gel permeation chromatography), $^1H$-NMR ($^1H$ nuclear magnetic resonance) and FT-IR (fourier transform infrared). TGA (thermogravimetric analysis) analysis showed that the prepared membranes were thermally stable, so that elevated temperature fuel cell operation would be possible. The proton conductivity of the FPBI membranes increased with increasing temperatures in the polymer. A FPBI membrane has a maximum ion conductivity of 45 mS/cm at $90^{\circ}C$ and 100% relative humidity.

• BMB Reports
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• v.32 no.2
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• pp.147-153
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• 1999

Previously, we reported that the prothrombin kringle 2 (fragment 2), induced by LPS administration into rabbit, inhibited bFGF-stimulated BCE cell growth (Lee et al., 1998). In this study, we cloned and overexpressed the kringle 2 domain of rabbit and human prothrombin as a fusion protein with the pelB leader sequence in E. coli using the T7 promoter. The fusion protein was cleaved during translocation into the peri plasmic space, and cleaved recombinant protein was readily isolated from whole cell lysate by DEAE-Sepharose and Sephacryl S-200 gel filtration chromatography. Both the recombinant rabbit and human prothrombin kringle 2 showed very similar biochemical and functional characteristics to the rabbit prothrombin kringle 2 purified from rabbit serum, in terms of abnormal electrophoretic migration and endothelial cell growth inhibitory activity.

• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.44-48
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• 1995

26 bacterial strains capable of growing on Terephthalic acid (TPA) in minimal medium were isolated from soil and wastewater by selective enrichment culture, and among them, one isolate which was the best in the cell growth and TPA degradation was selected and identified as Pseudomonas sp. T-1 by its characteristics. Cell growth almost revealed a stationary phase at 24 hrs after cultivation. Cell growth dramatically increased in a minimal medium containing 0.1% of TPA as a sole carbon source and TPA was not detected any more at 80 hrs after cultivation. Therefore, it is suggested that Pseudomonas sp. T-1 could be effectively used for the biological treatment of wastewater containing TPA.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.695-700
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• 2007

The cycloinulooligosaccharide fructanotransferase (CFTase) gene (cft) from Paenibacillus macerans (GenBank access code AF222787) was expressed on the cell surface of Saccharomyces cerevisiae by fusing with Aga2p linked to the membrane-anchored protein Aga1p. The surface display of CFTase was confirmed by immunofluorescence microscopy and enzymatic assay. The optimized reaction conditions of surface-displayed CFTase were as follows; pH, 8.0; temperature, $50^{\circ}C$; enzyme amount, 30 milliunit; substrate concentration, 5%; inulin source, Jerusalem artichoke. As a result of the reaction with inulin, cycloinulohexaose was produced as a major product along with cycloinuloheptaose and cycloinulooctaose as minor products.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.65.2-65.2
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• 2011

일반적으로 결정질 실리콘 태양전지에서는 junction depth가 얕아짐으로써 단파장 영역에서의 수집효율이 향상되고 Jsc가 상승하기 때문에 junction depth가 얕은 것이 좋다. 또, 태양전지의 효율을 높이기 위해서는 낮은 재결합 속도가 필요한데 이를 위해서도 얕은 junction depth가 필요하다. 하지만 junction depth가 너무 얕으면 FF와 Voc가 낮아져 효율이 떨어지므로 junction depth를 최적화 할 필요가 있다. 본 논문에서는 PC1D 시뮬레이션을 사용하여 표면 농도를 고정시키고 junction depth를 가변하면서 이에 따른 cell의 parameter변화를 관찰하였다. 그 결과, 면저항 $120{\Omega}/{\square}$에서부터 효율이 saturation되었고, 그에 따른 parameter 값은 FF=76.28%, Jsc=$38.17mA/cm^2$, Voc=596.5V이며 junction depth가 $0.1726{\mu}m$일 때 효율은 17.37%이다.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.373-381
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• 1994

An actinomycete strain, HSL-613 was isolated -from soil and identified by International Streptomyces Project (ISP) and chemotaxonomic methods. The spore chain of the strain HSL-613 appears in a spiral shape, and its spores are spherical shape with smooth surface. The cell wall contains LL-diaminopimelic acid (DAP). Menaquinone MK-9 (H$_{6}$, H$_{8}$) and iso- and anteiso-branched fatty acids were detected from whole cell extract. Sugars identified from whole cell extract include galactose, glucose, mannose and ribose, which are distinct from general sugar patterns of Streptomyces. Average G+C content in the chromosome is 59%. 5S rRNA of HSL-613 consists of 120 nucleotides as determined by comparing with that of a type strain Streptomyces griseus subsp. KCTC 9080. Through morphological, physiological, and chemical characterization, HSL-613 was identified and named as Streptomyces sp. HSL-613.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.163-166
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• 1995

Chemical modification of gelatin-based macroporous microcanier beads was achieved by increasing the charge density through incorporation of (diethylamino)ethylchloride-hydrochloride (DEAE:CI-HCI) or lysine, and this significantly improved the attachment and growth of HepG2 cells. When microcarriers were modified by the addition of 2% lysine, positive charge density was 0.95 meq/g-caniers. In case of modification of microcarriers with DEAE:CI-HCI, positive charge density was 0.6 meq/g-caniers. An increase in charge density of the microcaniers to improve cell attachment has facilitated the growth of the cells on macroporous gelatin microcaniers. Also, final HepG2 cell concentration cultivated on modified beads with DEAE:CI-HCI was increased up to $10^7$ cells/ml. This was 2-3 times higher than that obtained with unmodified macroporous gelatin microcarriers.