• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
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• pp.178-181
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• 2000

In order to develop the novel gene expression system, we introduced new control elements which could influence the foreign gene expression in animal cells. When the foreign genes are introduced into the genome of higher eukaryotic cells, the expressions from these integrated genes are often low and can vary greatly depending on the positions of the integration sites due to the complex nature of the chromatin structures (1). First we screened the various DNA sequence elements which can function as an insulator of gene expression from these position effects and can cooperate with the SV40 enhancer/promoter. Among the several DNA elements from the various sources, we identified the particular DNA element which confers the increased frequency of the positive colonies, assayed by the reporter gene from stable selections indicating significantly reduced position effects. This element also showed the several fold-increased expression level as well as the copy-number dependent expression with host cell specificity. Second we modified the transcription termination element where we introduced the specific terminator in combination with SV40 polyA signal. This modified terminator showed the increased efficiency and the level of the gene expression. By combining these two elements, we made the animal cell expression system and tested successfully for the recombinant protein productions of TGF ${\beta}$-soluble receptor, Antithrombin III, and single chain Pro-Urokinase. [Supported by grants from MOCIE]

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.98-105
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• 1999

Intestinal bacteria comprise one-third of the contents of the large intestine in humans. Their interactions with the gastrointestinal immune system induce characteristic immunological responses which stimulate or suppress the host's defense system. RAW 264.7 murine cell line was used as a macrophage model to assess the effects of the exposure to the isolated human intestinal bacteria, Bacteroides, Bifidobacterium, Eubacterium, Streptococcus, and E. coli, on NO (nitric oxide), $H_2O_2$(hydrogen peroxide), and cytokines IL (interleukin)-6 and TNF (tumor necrosis factor)-a production. RAW 264.7 cells were cultured in the presence of heat-killed bacteria for 24 h at concentrations of 0-$50\mu$g/ml. Our results showed that Bacteroides and E. coli stimulated IL-6, TNF-$\alpha$, NO, and $H_2O_2$production at high levels even at $1\mu$g/ml, whereas Bifidobacterium, Eubacterium, and Streptococcus showed a low level of stimulation at $1\mu$g/ml, and a gradual increase as the cell concentration increased up to $50\mu$g/ml. This result suggests that gram-negative Bacteroides and E. coli are better able to stimulate macrophage than gram-positive Bifidobacterium, Streptococcus, and Eubacterium. The in vitro approaches employed here should be useful in further characterization of the effects of intestinal bacteria on gastrointestinal and systemic immunity.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.673-679
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• 2003

Glutamine and urea, abundant in body fluids or plasma, yield net ammonium ions upon hydrolysis by ${\gamma}-glutamyl$ transpeptidase (${\gamma}-GTP$) and urease, respectively, and these two enzymes are largely produced from Helicobacter pylori. To investigate bacterial potential of ammonium production, we first quantified those in whole-cell systems and found that the relative ratio of their amounts varied greatly, especially with pH values and the cell's aging. During the H. pylori cultivation, the ratio appeared to be inversely proportional to each other, showing a progressive increase of the ${\gamma}-GTP$ with decreasing of the urease. Under the urease-defective conditions due to low pH or coccoids, the bacterial cells still possessed a considerable amount of ${\gamma}-GTP$, which was found exclusively in the external compartment, therefore, the cell's ammonium production was found to be solely dependent upon glutamine, and the external ammonium concentration was constant without any contribution of urea concentration. Such ammonium constancy would definitely have an adverse effect on the host, because of its absolute requirement for vacuolar degeneration by H. pylori VacA, maximized at approximately 10 mM $NH_4Cl$. It was also found that, by using the metal-saturated membrane vesicles, ammonium ions were likely to be involved in the pH-dependent cation-flux across the H. pylori membrane, where the role of ${\gamma}-GTP$ in ammonium homeostasis around cells was suggested, especially under the hostile conditions against H. pylori.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1817-1829
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• 2019

Porcine deltacoronavirus (PDCoV) is an emerging swine enteric coronavirus that causes diarrhea in neonatal piglets. Like other coronaviruses, PDCoV encodes at least three accessory or species-specific proteins; however, the biological roles of these proteins in PDCoV replication remain undetermined. As a first step toward understanding the biology of the PDCoV accessory proteins, we established a stable porcine cell line constitutively expressing the PDCoV NS7 protein in order to investigate the functional characteristics of NS7 for viral replication. Confocal microscopy and subcellular fractionation revealed that the NS7 protein was extensively distributed in the mitochondria. Proteomic analysis was then conducted to assess the expression dynamics of the host proteins in the PDCoV NS7-expressing cells. High-resolution two-dimensional gel electrophoresis initially identified 48 protein spots which were differentially expressed in the presence of NS7. Seven of these spots, including two up-regulated and five down-regulated protein spots, showed statistically significant alterations, and were selected for subsequent protein identification. The affected cellular proteins identified in this study were classified into functional groups involved in various cellular processes such as cytoskeleton networks and cell communication, metabolism, and protein biosynthesis. A substantial down-regulation of α-actinin-4 was confirmed in NS7-expressing and PDCoV-infected cells. These proteomic data will provide insights into the understanding of specific cellular responses to the accessory protein during PDCoV infection.

• 정보처리학회논문지C
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• 제13C권2호
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• pp.227-234
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• 2006

본 논문에서는 모바일 네트워크에서 자원 예약으로 인해서 낭비되는 무선 자원을 개선하기 위한 윈도우 기반 자원 예약 기법을 제안한다. 특히 이 기법은 차별화 된 핸드오프 예측 모델을 기반으로 모바일 호스트들이 셀에서 이동하는 횟수를 이용하여 적절한 자원 예약 시점을 결정한다. 기존의 자원 예약 기법에서는 모바일 호스트가 셀에 도착하거나 생성되면 바로 자원 예약을 요청한다. 그러나 본 논문에서 제안하는 기법은 차별화 된 핸드오프 예측 모델에서 제공하는 추정된 내부 영역 이동 횟수를 기반으로 일정 시간이 경과한 후에 자원을 예약하므로 자원 이용율을 향상시킬 수 있다. 그리고 이웃 셀들에 대한 자원 예약 요청 비율에 따라 차별화 된 자원 예약을 실시하여 전체적인 자원 예약 성공율 및 대역폭 이용율을 향상시킨다.

• IMMUNE NETWORK
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• 제12권6호
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• pp.277-283
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• 2012

Vitamin C is an essential water-soluble nutrient which primarily exerts its effect on host defense mechanisms and immune homeostasis, but the mechanism related to immune-potentiation is poorly understood. Since dendritic cells (DCs) are known as a potent antigen presenting cell (APC) that could enhance the antigen specific immune responses, we investigate the effects of vitamin C on activation of DCs and its related mechanism by using dendritic cell lines, DC-1. First, we found that there was no damage on DC-1 by 2.5 mM of vitamin C. In the presence of vitamin C, the expression of CD80, CD86, and MHC molecules was increased, but it was decreased by the pre-treatment of SB203580, p38 MAPK-specific inhibitor. We confirmed the phosphorylation of p38 MAPK was increased by the treatment of vitamin C. Taken together, these results suggest that vitamin C could enhance the activity of dendritic cells via the up-regulation of the expression of CD80, CD86, and MHC molecules and the activation of p38 MAPK is related to this process.

• Clinical and Experimental Pediatrics
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• 제58권6호
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• pp.199-205
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• 2015

Severe aplastic anemia (SAA) is a life-threatening disorder for which allogeneic hematopoietic stem cell transplantation (HSCT) is the current available curative treatment. HSCT from matched sibling donors (MSDs) is the preferred therapy for children with acquired SAA. For patients who lack MSDs, immunosuppressive therapy (IST) is widely accepted as a first-line treatment before considering HCT from an unrelated donor (URD). Given the recent progress in HSCT using URDs for childhood SAA, well-matched URDs became a realistic alternative for pediatric patients who have no suitable related donors and who are refractory to IST. However, it is quite challenging to treat patients with refractory SAA who lack suitable related or URDs. Even though haploidentical HSCT from genetically mismatched family members seemed to be an attractive procedure with the amazing benefit of readily available donors for most patients, early attempts were disappointing because of refractory graft-versus-host disease (GVHD) and excessively high transplant-related mortality. Recent advances with effective ex vivo depletion of T cells or unmanipulated in vivo regulation of T cells, better supportive care, and optimal conditioning regimens have significantly improved the outcome of haploidentical transplant. Besides considerable progress in the treatment of malignant diseases, recent emerging evidences for haploidentical HSCT in SAA has provided additional therapeutic options for patients with refractory diseases. Further improvements to decrease the rates of graft failure, GVHD, and infectious complications will facilitate the emergence of haploidentical HSCT as a front-line therapy for treating acquired SAA in children and adolescents who have no suitably matched donors.

• Clinical and Experimental Pediatrics
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• 제59권6호
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• pp.252-255
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• 2016

Purpose: Pneumocystis jirovecii pneumonia occurs in various immunocompromised patients. Despite the prophylaxis strategies in clinical practice, certain patients develop P. jirovecii pneumonia. This study was performed to investigate pediatric cases with P. jirovecii pneumonia in a single center. Methods: We identified pediatric patients younger than 19 years with microbiologically confirmed P. jirovecii pneumonia from January 2000 to February 2014. A retrospective chart review was performed. Results: Fifteen episodes of P. jirovecii pneumonia in 14 patients were identified with median age of 8.3 years (range, 0.4-18.6 years). Among these patients, 11 patients had hematology-oncology diseases, 2 had primary immunodeficiency disorders (one with severe combined immunodeficiency and the other with Wiskott Aldrich syndrome), 1 had systemic lupus erythematosus and 1 received kidney transplant. Four patients were transplant recipients; 1 allogeneic and 2 autologous hematopoietic cell transplant and 1 with kidney transplant. The median absolute lymphocyte count at the diagnosis of P. jirovecii pneumonia was $5,156cells/mm^3$ (range, $20-5,111cells/mm^3$). In 13 episodes (13 of 15, 86.7%), patients were not receiving prophylaxis at the onset of P. jirovecii pneumonia. For treatment, trimethoprim/sulfamethoxazole was given as a main therapeutic agent in all 15 episodes. Steroid was given in 9 episodes (60%). Median treatment duration was 15 days (range, 4-33 days). Overall mortality at 60 days was 35.7% (5 of 14). Conclusion: Majority of our patients developed P. jirovecii pneumonia while not on prophylaxis. Continuous efforts and more data are needed to identify high risk patients who may get benefit from P. jirovecii pneumonia prophylaxis.

• 한국응용곤충학회지
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• 제34권2호
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• pp.112-119
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• 1995

본 연구는 뿌리썩이선충(Pratylenchus vulnus)이 옥수수뿌리조직을 침입했을 때, 조직의 해부학적.생화학적 변화를 밝힘으로써 식물과 선충의 상호관계를 이해하고, 이들 정보를 바탕으로 선충저항성 작물의 육종 및 선별에 활용하기 위함이다. 옥수수뿌리 표피를 뚫고 들어온 선충은 뿌리 피층에 자리를 잡고, 세포벽을 파괴하면서 다른 세포로 이동한다. 마침내 선충들은 피층의 내피와 세근의 기부에 밀집했다. P.vuinus의 암컷들은 세포내에 공간(cavity)을 형성하여 그 속에 알을 낳는 습성을 지니고 있다. 선충에 의한 주된 피해양상은 세포벽이 파괴되고 부서져서 공간을 형성하는 것으로 나타난다. 이러한 현상은 세근의 기부에서도 관찰된다. 선충의 피해로 야기된 옥수수 뿌리의 생화학적 변화는 선충접종구와 무접종구간 총단백질양과 esterase활력조사를 통해 비교.분석되었다. Denaturing gel 상에서 총단백질양의 비교는 유의한 차이를 나타내지 않았고, esterase 의 pattern 및 활력에서도 유의할 만한 차이는 발견되지 않았다.

• 대한수의학회지
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• 제35권2호
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• pp.317-326
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• 1995

The purpose of this study was to establish a method for in vitro culture of C parvum isolated in Korea by determination of suitable cell model to complete development of this parasite. The result obtained were summerized as follows: 1. To determine the most suitable cell line, six types of cell line were examined by microscopy. All cell lines were infected with C parvum and showed the highest infection score in HmLu cells. 2. The staining methods including DMSO-modified acid-fast(A-F) stain, hematoxylin-eosin(H & E) stain and immunofluorescence antibody(IFA) stain were applied to examine the infection of C parvum in cell culture. These staining methods were possible to examine the infection of C parvum in cell culture. The most sensitive one was IFA staining technique. 3. Developmental stages of C parvum in HmLu cell were observed. After the initial 8 hour incubation period, some trophozoites were observed. The meronts and gametes were appeared at 24-48 hour post inoculation(PI), and oocysts were observed firstly at 48-72 hour PI. 4. In H & E stain, the parasite appeared as basophilic within parasitophorous vacuole membrane(PVM) and lying in cytoplasm at near the nucleus of the host cells. It was able to distinguish the type I, type II meronts and gametes. 5. In DMSO-modified acid-fast stain, specific stained parasites were appeared firstly after 48 hour PI. The parasites were showed with different degrees of staining bright red color within PVM. 6. The endogenous stages of parasites in HmLu cell recovered at 48, 96, 120 and 144 hour after inoculation were reacted with rabbit immunized serum in immunofluorescence antibody and avidin-biotin complex peroxidase staining technique.