• 대한수의학회지
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• 제35권1호
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• pp.87-94
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• 1995

Western immunoblot analysis of antigen of T sergenti merozoite revealed that the immunodominant proteins of this organism were characterized as the 18KD, 29KD, 34KD, 45KD and 105KD in Korea. The 34KD and 45KD among those immunodominant proteins of the parasite were isolated and their amino acid sequences from the $NH_2$-terminus were determined and synthesized. They respective polypeptides were cationized to enhance their antigenicity, fortified with Freund's adjuvant and tested for immunogenicity in rabbits and cattle. The results obtained were as follows; 1. Theileria sergenti merozoite antigen was shown in 120KD, 100KD, 66KD, 45KD, 34KD and 30KD in western immunoblot using serum of rabbits immunized with 34KD synthetic polypeptide and 70KD, 58KD, 55KD and 45KD using bovine serum. In western immunoblot, 45KD, 34KD and 30KD were recognized by immunized rabbits, and 50KD and 45KD by cattle sera immunized with 45KD synthetic polypeptide, respectively. 2. The ELISA utilizing the synthetic polypeptides demonstrated significant antibody response to the respective peptides. After the 2nd booster injection, an OD of 0.760(preimmunization 0.132) in rabbits and an OD of 0.645(preimmunization 0.488) to 34KD synthetic polypeptide in cattle were observed. In animals immunized with 45KD synthetic polypeptide, after the 2nd booster injection, an OD of 0.640(preimmunization 0.144) in rabbit, and an OD of 0.776 (preimmunization 0.477) in cattle were measured. 3. After the 2nd booster the reciprocal IFA titer was 1:64 in rabbits and 1:512 in cattle immunized with the 34KD synthetic polypeptide. The IFA titre was observed as 1:512 in rabbit and 1:1,024 in cattle in immunized with the 45KD synthetic polypeptide.

• 대한수의학회지
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• 제36권2호
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• pp.453-461
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• 1996

Eighteen holstein-calves(4~5 months old) in a divided groups including the matched control were immunized with $100{\mu}g/dose$ of 34kDa, 45kDa polypeptide and T sergenti merozoite vaccine(protein content $100{\mu}g/dose$) respectively, previously mixed with aluminium hydroxide to elicit antibodies. All groups of calves were boosted with same dose and intervals. The animals were challenged by tick infestations in the endemic pasture of theileriosis from March to September 1994. The animals were monitored for the erythrocyte count, parasitemia, hematocrit and the specific antibody reactions elicited by immunization. The immunological responses demonstrated that vaccination with 34kDa polypeptide and T sergenti merozoite derived vaccine inhibited to produce the 75kDa band immunological responds even in the vaccinated calves after being challenged by tick infestations in the pasture. However, the specific antibody reactions were detected at the 32kDa band in the nonimmunized calves and T sergenti merozoite derived vaccine by the western blot. The 34kDa polypeptide vaccine and T sergenti merozoite derived vaccine were evaluated to be able to protect inducing anemia and to decrease parasitemias level. These vaccines have the efficacy of inhibition to produce a certain antigen corresponding 75kDa band antigen of parasite in the calves as challenged with tick infestations.

• BMB Reports
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• 제29권1호
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• pp.58-62
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• 1996

The structural changes in the electron donor side of the PSII reaction center have been monitored since heat treatment ($45^{\circ}C$ for 5 min) of thylakoids is known to decrease the oxygen evolving activity. In heat-treated spinach chloroplast thylakoids, the inhibitory effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the electron transport activity of the PSII reaction center from diphenyl carbazide to dichlorophenolindophenol became reduced approximately 3.8 times and [$^{14}C$]-labeled DCMU binding on the D1 polypeptide decreased to 25~30% that of intact thylakoid membranes, implying that the conformational changes of the DCMU binding pocket, residing on the D1 polypeptide, occur by heat treatment. The accessibility of trypsin to the $NH_2$-terminus of the cytochrome b-559 ${\alpha}$-subunit, assayed with Western blot using an antibody generated against the synthetic peptide (Arg-68 to Arg-80) of the COOH-terminal domain, was also increased, indicating that heat-treatment caused changes in the structural environments near the stromal side of the cytochrome b-559 ${\alpha}$-subunit, allowing trypsin more easily to cleave the $NH_2$-terminal domain. Therefore, the structural changes in the electron donor side of the PSII reaction center complexes could be one of the reasons why the oxygen evolving activity of the heat-treated thylakoid membranes decreased.

• Parasites, Hosts and Diseases
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• 제32권2호
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• pp.111-116
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• 1994

우리나라 소에 유행하고 있는 Theileria sergenti의 예방을 위한 연구의 일환으로 긴sergeki merozoite 수용성 항원중에서 면역원성 물질로 보고한 바 있는 34. 29 및 18 kDa와 항원성 물질인 45 kDa에 대하여 Peptdie 구성 특성을 밝히기 위하여. 이들 물질에 대한 아미노산 서열을 결정하였다. 이를 생합성하여 Chou-Fasmanprediction법에 의해 항원 결정기를 확인하였던 바. 45 kDa. 34 kDa. 29 kDa 그리고 18 kDa의 Polypeptide는 6 4 2 그리고 0 개의 항원 결정기를 갖고 있었다. 그런데 45 kDa 물질은 항 T. serpenti혈청에 대하여 면역원성이 인정되않았던 물질이었다.

• 한국미생물·생명공학회지
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• 제19권3호
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• pp.228-234
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• 1991

DNA 자동합성기를 이용하여 오릴고뉴클레오타이드들을 합성하였으며 이로부터 인간 인터루킨-2를 코드하는 유전자를 제조하였다. 합성 유전자의 염기서열은 대장균에서 사용빈도가 높은 코돈을 고려하여 결정하였으며, 이때 인터루킨-2의 아미노산 서열은 변화시키지 않았다. 합성된 유전자는 람다 피엘 프로모터를 사용하여 대장균에서 발현시켰다. 인터루킨-2는 대장균에서 불용성의 침전물로 생성되었다. 생성된 인터루킨-2는 인터루킨-2 요구 배양세포주의 성장을 촉진하였다.

• 대한의생명과학회지
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• 제19권1호
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• pp.41-47
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• 2013

Pluripotent stem cells (PSCs) have lots of potential in biomedical sciences owing to its potential to differentiate into any kind of cells in the body. However, it is still a challenge to culture PSCs on a large scale for application to regenerative medicine. Herein, we introduce a synthetic polymer that enables large-scale suspension culture of human PSCs. By employing suspension culture, it became unnecessary to use conventional substrata such as mouse embryonic fibroblast (MEF) or Matrigel$^{TM}$, which are believed to be main causative sources of xenogeneic contamination in cultured human PSCs in vitro. Human PSCs were cultured in the medium in which elastin-like polypeptide (ELP) dissolved. The ELP in the medium became harden as temperature increases by transforming the medium into a semi-solid gel that supported growth of human PSCs in suspension. Gel-sol transition temperature of ELP can be adjusted by modifying the peptide sequence in which 5 amino acids, Val-Pro-Gly-Xaa-Gly, repeated sequentially. We constructed 3D suspension media having transition temperature around $33{\sim}35^{\circ}C$ using an ELP consisted of 40, 60, or 80 repeats of a monomer, which was Val-Pro-Gly-Val-Gly. Among the ELPs, ELP80 was chosen as the best ELP to support growth of human PSCs in suspension culture. This result suggests that the ELP80 can be a medium component for culturing human PSCs in large-scale.

• Clinical and Experimental Pediatrics
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• 제48권6호
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• pp.580-587
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• 2005

New evidence is emerging that airway smooth muscle(ASM) may act as an immunomodulatory cell by providing pro-inflammatory cytokines and chemokines, polypeptide growth factors, extracellular matrix proteins, cell adhesion receptors and co-stimulatory molecules. ASM can promote the formation of the interstitial extracellular matrix, and potentially contribute to the alterations within the extracellular matrix in asthma. In addition, extracellular matrix components can alter the proliferative, survival, and cytoskeletal synthetic function of ASM cells through integrin-directed signaling. Increased ASM mass is one of the most important features of the airway wall remodeling process in asthma. Three different mechanisms may contribute to the increased ASM mass : cell proliferation, increased migration and decreased rate of apoptosis. The major signaling pathways of cell proliferation activated by ASM mitogens are those dependent on extracellular signal-regulated kinase and phosphoinositide 3'-kinase. The key signaling mechanisms of cell migration have been identified as the p38 mitogen-activated protein kinase and the p21-activated kinase 1 pathways. ASM cells contain ${\beta}2$-adrenergic receptors and glucocorticoid receptors. They may represent a key target for ${\beta}2$-adrenergic receptor agonist/corticosteroid interactions which have antiproliferative activity against a broad spectrum of mitogens.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.59-64
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• 2002

An angiotensin I-converting enzyme (EC 3.4.15.1) (ACE), which can convert inactive angiotensin I into angiotensin II, a vasoconstrictor, is one of the key enzymes in controlling hypertension. It is suggested that the inhibition of ACE prevents hypertension, and many inhibitory peptides have already been reported. In the current study, oligonucleotides encoding ACE inhibitory peptides (IY, VKY) were chemically synthesized and designed to be multimerised due to isoschizomer sites (BamHI, BglII). The cloned gene named AP3 was multimerised up to 6 times in pBluescript and expressed in BL2l containing pGEX-KG. The fusion protein (GST-AP3) was easily purified with a high recovery by an affinity resin, yielding 38 mg of synthetic AP3 from a 1-1 culture. The digestion of AP3 by chymotrypsin exhibited an $IC_50$ value of $18.53{\mu}M$. In conclusion, the present experiment indicated that AP3 could be used as a dietary antihypertensive drug, since the potent ACE inhibitory activity of AP3 could be activated by chymotrypsin in human intestine.

• Bulletin of the Korean Chemical Society
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• 제27권8호
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• pp.1099-1114
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• 2006

Our studies in the area of single electron transfer (SET) photochemistry have led to the discovery of efficient processes, in which regioselective formation of carbon-centered radicals takes place by nucleophile assisted desilylation of $\alpha$-trialkylsilyl substituted ether, thioether, amine and amide centered cation radicals. The rates of bimolecular desilylation of the intermediate cation radicals exceed those of other cation radical $\alpha$-fragmentation processes (e.g.,-deprotonation). This sereves as the basis for the design of highly regioselective, SET-induced photomacrocyclization reactions of polyether, polythioether, polyamide, and polypeptide linked phthalimides. Photocyclization reactions of trimethylsilyl-terminated substrates in these families are unique in that they produce polyfunctionalized macrocyclic substances in a highly efficient and regioselective manner. In addition, our studies in this area have led to important information about the factors that govern chemical and quantum efficiencies that should be applicable to a wide variety of redox processes promoted by SET from substrates containing more than one electron donor site.

• Journal of Periodontal and Implant Science
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• 제26권4호
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• pp.841-858
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• 1996

Epidermal growth factor(EGF) is one of polypeptide growth factors. EGF has been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. The purposes of this study is to evaluate the effects of EGF on the human periodontal ligament cells and human gingival fibroblast cells that promote regeneration of periodntal tissue. The mitogenic effects of epidermal growth factor on human periodontal ligament cells and human gingival fibroblasts were evaluated by determining the incorporation of 5-Bromo-2'-deoxy-uridine into DNA of the cells in a dose dependent manner. The prepared cells were the primary cultured gingival fibroblast and periodontal ligament cells from humans, the fourth or sixth subpassages were used in the experiments. Cells were seeded in DMEM containing 10% FBS. 1, 10, 50, 100, $200{\eta}g/ml$ and epidermal growth factor were added to the quiescent cells for 24 hours, 48 hours and 72 hours. They were labeled with $10\{mu}l/200{\mu}l$ 5-Bromo-2'-deoxy-uridine for the last 6 hours of each culture. The results of the five determinants were presented as mean and S.D.. The results were as follows : The DNA synthetic activity of human gingival fibroblasts were increased dose dependently by epidermal growth factor at 24 hours, 48 hours and 72 hours. The mitogenic effects were similar at the 24 and 48 hours of epidermal growth factor, but the DNA synthetic activity of human gingival fibroblasts generally decreased at 72 hours. The DNA synthetic activity of human periodontal ligament cells were increased dose dependently by epidermal growth factor at 24 hours but the DNA synthetic activity decreased at $200{\eta}g/ml$ of each hour. Generally the maximum mitogenic effects were observed at the 48 hours application of epidermal growth factor. The DNA synthetic activity of human periodontal ligament cells generally decreased lower at 24, 72 hours than at 48 hours the application of epidermal growth factor. In the comparison of DNA synthetic activity between human gingival fibroblasts and human periodontal ligament cells, human periodontal ligament cells had slightly higher proliferation activity than human gingival fibroblasts for a longer time at the high dosage of the epidermal growth factor. In conclusion, epidermal growth factor have important roles in the stimulation of DNA synthesis in human periodontal ligament cells and human gingival fibroblasts, and thus may be useful for clinical applications in periodontal regenerative procedures.