• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.603-614
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• 2002

Human gingival fibroblasts have proven to useful as a species specific cell culture system in various system on periodontal disease and regeneration. However, their use is limited, since they are hard to obtain and lifespan is short due to replicative senescence. To overcome these disadvantages, we transfected primary human gingival fibroblasts by the E6 and E7 genes of the Human papilloma virus(HPV) 16. The full length of HPV 16 E6 and E7 was cloned from the pBR322 into BamHl and Sal I of a pBabe vector including hygromycin B resistance. Before pBabeE6/E7 plasmid transfection, peak 8 GFP including G418 resistance was transfected into primary GF to check the transfection efficency. PBabe E6/E7 plasmid was transfected using Lipofectamine plus following manufacter's instruction into primary normal human gingival fibroblasts in 60mm dishes with FBS free DMEM. After 2 days of transfection, the cells were treated with hygromycin for 2 weeks until the transfected control cells died. The resulting hygromycin resistant colonies were pooled, and clonned, and sucessful　transfection was established for immortalized gingival fibroblast cell lines. Immoralized GF cells showed stellate shape, that is similar to that of orange grains, and more rapid growth and higher proliferation than that of primary gingival fibroblasts. This cell lines overcame crisis and could be cultured over 30 subcultured, could be use for three dimentional culture, epithelial-mesenchymal interaction study.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.485-487
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• 1994

A novel control scheme for a Switched Reluctance Motor(SRM) drive is described. The control scheme which is to increase torque, to decrease torque ripples and easy to commutate is suggested. The conditions for high torque drive which includes flat-topped phase current and voltage control arc analyzed and adopted in this control scheme. Flat-topped current is achived via dc-link voltage control. The suggested control system was tested to verify this suggestion.

• The KIPS Transactions:PartB
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• v.17B no.3
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• pp.249-254
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• 2010

We propose an automatic spam filter for e-mail data using Support Vector Machines(SVM). We use a lexical form of a word and its part of speech(POS) tags as features and select features by chi square statistics. We represent each feature by TF(text frequency), TF-IDF, and binary weight for experiments. After training SVM with the selected features, SVM classifies each e-mail as spam or not. In experiment, the selected features improve the performance of our system and we acquired overall 98.9% of accuracy with TREC05-p1 spam corpus.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1293-1298
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• 2018

Phosphomannomutase (ManB) converts mannose-6-phosphate (M-6-P) to mannose-1-phosphate (M-1-P), which is a key metabolic precursor for the production of GDP-D-mannose used for production of glycoconjugates and post-translational modification of proteins. The aim of this study was to express the manB gene from Escherichia coli in Lactococcus lactis subsp. cremoris NZ9000 and to characterize the encoded enzyme. The manB gene from E. coli K12, of 1,371 bp and encoding 457 amino acids (52 kDa), was cloned and overexpressed in L. lactis NZ9000 using the nisin-controlled expression system. The enzyme was purified by Ni-NTA column chromatography and exhibited a specific activity of 5.34 units/mg, significantly higher than that of other previously reported ManB enzymes. The pH and temperature optima were 8.0 and $50^{\circ}C$, respectively. Interestingly, the ManB used in this study had two substrate specificity for both mannose-1-phosphate and glucose-1-phosphate, and the specific activity for glucose-1-phosphate was 3.76 units/mg showing 70% relative activity to that of mannose-1-phosphate. This is the first study on heterologous expression and characterization of ManB in lactic acid bacteria. The ManB expression system constructed in this study canbe used to synthesize rare sugars or glycoconjugates.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.45-53
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• 2005

GroE that is a heat shock protein composed of GroEL and GroES is known as an immunodominant target of both the humoral and cellular immune responses in bovine brucellosis. This study was carried out to characterize groE gene encoding heat shock proteins of B. abortus isolated in Korea and to evaluate the immunogenicity of the GroE protein expressed in E. coli system. In PCR the specific signals with the size of 2,077 bp were detected in five strains isolated from the mammary lymphnodes of the dairy cattle that were serologically positive and the reference strains. In comparison of the sequences of nucleotides and amino acids among the strains, GroES showed 100% identity in both sequences. GroEL was evaluated 99.0~99.9% in nucleotides and 98.0~100% homology in amino acids. The groE gene including groES and groEL was inserted into pET29a vector and constructed pET29a-GroE recombinant plasmids. The inserted groE was confirmed by digestion with Nco1 and EcoR1 endonucleases and nucleotide sequencing. E. coli BL (DE3) was transformed with pET29a-GroE, named as E. coli BL (DE3)/pET29a-GroE. In SDS-PAGE, it was evident that the recombinant plasmid effectively expressed the polypeptides for GroES (10 kDa) and GroEL (60 kDa) in 0.5, 1 and 2 hours after IPTG induction. The immuno-reactivity of the expressed proteins were proved in mouse inoculation and Western blot analysis.

• Animal cells and systems
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• v.15 no.1
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• pp.29-36
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• 2011

Insect lysozymes are basic, cationic proteins synthesized in fat body and hemocytes in response to bacterial infections and depolymerize the bacterial cell wall. The c-type lysozyme of the insect Spodoptera litura (SLLyz) is a single polypeptide chain of 121 residues with four disulfide bridges and 17 rare codons and is approximately 15 kDa. The full-length SLLyz cDNA is 1039 bp long with a poly(A) tail, and contains an open reading frame of 426 bp long (including the termination codon), flanked by a 54 bp long 5' UTR and a 559 bp long 3' UTR. As a host for the production of high-level recombinant proteins, E. coli is used most commonly because of its low cost and short generation time. However, the soluble expression of heterologous proteins in E. coli is not trivial, especially for disulfide-bonded proteins. In order to prevent inclusion body formation, GST was selected as a fusion partner to enhance the solubility of recombinant protein, and fused to the amplified products encoding mature SLLyz. The expression vector pGEX-4T-1/rSLLyz was then transformed into E. coli BL21(DE3)pLysS for soluble expression of rSLLyz, and the soluble fusion protein was purified successfully. Inhibition zone assay demonstrated that rSLLyz showed antibacterial activity against B. megaterium. These results demonstrate that the GST fusion expression system in E. coli described in this study is efficient and inexpensive in producing a disulfide-bonded rSLLyz in soluble, active form, and suggest that the insect lysozyme is an interesting system for future structural and functional studies.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.345-348
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• 1985

Recombinant chimeric plasmid constructed with Xba I digested pUBl10 and -pE194 was transformed by polyethylene glycol induced protoplast transformation system into Bacillus subtilis BR 151 on the mannitol regeneration media, and two genes of antibiotics resistance were expressed simultaneously in the transfromant. Transformation frequency of the recombinant plasmid was 6.5 $\times$ 10$^{-5}$ on the mannitol regeneration agar plate containing neomycin and erythromycin. The replication of recombinant plasmid in the recipient cells was confirmed by the alkaline extraction method and agarose gel electrophoresis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.773-778
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• 2015

The local heat transfer and pressure drop of developed turbulent flows in convergent/divergent channels with square axial cross-sectional areas were experimentally investigated to improve the channel design, such as a gas turbine cooling system. Square convergent/divergent channels with one ribbed wall were manufactured with a fixed rib height e of 10 mm and a ratio of rib spacing p to height e of 10. The measurement was conducted for Reynolds numbers from 15,000 to 89,000. Convergent, divergent, and straight channels with ratios $D_{ho}/D_{hi}$ of 0.75, 1.33, and 1.0, respectively, are considered. Of the three channel types, the ribbed divergent channel was found to produce the best thermal performance under identical flow rate, pumping power, and pressure loss conditions.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1024-1030
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• 2007

We investigated the human apolipoprotein E2 (apoE2) transgenic mouse as an animal model system for age-related macular degeneration (AMD). Transgenic mice expressing human apoE2 and C57BL/6J mice were fed normal chow or a high-fat diet for 4 weeks. Eyes were collected from the mice and lipid deposits in retinal pigment epithelium (RPE) were assessed using electron microscopy. The expressions of apoE, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and pigment-epithelium derived factor (PEDF), which are molecular markers for angiogenesis, were assessed with immunohistochemistry. Eyes from apoE2 mice, regardless of diet, contained lipid accumulation in RPE under electron microscopy, whereas control C57BL/6J eyes did not. Lipid accumulation was found predominantly in the RPE and the Bruch's membrane and increased in the eyes of apoE2 mice after one month of a high-fat diet ($8{\pm}2\;per\;50{\mu}m^2$ for normal chow and $11{\pm}2\;per\;50\;{\mu}m^2,\;p<0.05)$. ApoE expression was similar in the apoE2 and control mice; however, VEGF and bFGF were overexpressed in the retinal pigment epithelium of apoE2 eyes compared with control eyes, and PEDF expression was slightly decreased. These expression patterns of VEGF, bFGF, and PEDF suggest angiogenesis is progressing in apoE2 eyes. In conclusion, the eyes of apoE2 mice develop typical lipid accumulations, a common characteristic of AMD, making them a suitable animal model for AMD. The expression profile of VEGF and bFGF on the retinal pigment epithelium suggests that apoE2 may induce neovascularization by altering angiogenic cytokines.

• Journal of Nutrition and Health
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• v.50 no.3
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• pp.236-245
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• 2017

Purpose: The aim of this study was to assess the effects of guava leaf extract (GLE) supplementation on antioxidant enzyme activity and expression of endothelial nitric oxide synthase (eNOS) mRNA in ovariectomized rats. Methods: All animals were randomly assigned to four groups (n = 7 for each group): non-ovariectomized control (Sham), the ovariectomized control (OVX), ovariectomy + 150 mg/kg b.w. of GLE ($OVX{\cdot}GL$), and ovariectomy + 300 mg/kg b.w. of GLE ($OVX{\cdot}GH$). Treatment groups were administered GLE for 8 weeks every day. Results: Body weight gain was significantly reduced in the $OVX{\cdot}GL$ group compared with the OVX group (p < 0.05). The level of serum $17{\beta}$-estradiol (E2) was significantly lower in the OVX groups than the Sham group (p < 0.05). Serum triglyceride (TG) and HDL-cholesterol levels were not significantly different between all groups. However, serum total cholesterol (TC) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Serum free fatty acid (FFA) level and liver TG level were significantly reduced in both $OVX{\cdot}GL$ and $OVX{\cdot}GH$ groups compared with the OVX group (p < 0.05). Furthermore, serum glutathione peroxidase (GPx) activity was significantly elevated in the GLE groups (p < 0.05). The mRNA expression level of GPx was not affected by ovariectomy. However, administration of GLE resulted in significantly increased nuclear factor erythroid 2-related factor (Nrf2) and catalase (CAT) mRNA expression levels in the liver (p < 0.05). In addition, liver nitric oxide (NO) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Expression level of endothelial nitric oxide synthase (eNOS) was significantly elevated in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Conclusion: These results suggest that GLE could have protective effects in OVX rats by stimulating eNOS expression and improving the antioxidant defense system.