• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.1-14
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• 2004

More than twenty years have passed since the approval of the first recombinant DNA product for therapeutic use (recombinant human insulin, 1982). However, the biotechnology industry is still facing a shortage of manufacturing capacity due to the increasing demand of therapeutic proteins. This demand has prompted the search for a growing number of biological production systems but, nevertheless, the Gram-negative bacterium Escherichia coli remains one of the most attractive production hosts. This review highlights the most important features and developments of plasmid vector design, emphasizing the different reported strategies for improving the expression and secretion of heterologous proteins using the cellular machinery of E. coli.

• Journal of Microbiology and Biotechnology
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• 제5권6호
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• pp.370-372
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• 1995

A Phaffia rhodozyma chromosomal fragment (approximately 3.8 kb) capable of functioning as an origin for the replication of a kanamycin resistance ($Km^r$) plasmid in S. cerevisiae was isolated by the use of origin search plasmid, pHN134. In S. cerevisiae, transformation frequencies using the plasmid pHN134 containing an autonomously replicating sequence of P. rhodozyma was 450-580 CFU/$\mu g$ DNA. The stability of the recombinant plasmid were 16-19$\%$.

• IMMUNE NETWORK
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• 제5권2호
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• pp.89-98
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• 2005

Background: DNA vaccination represents an anticipated approach for the control of numerous infectious diseases. Used alone, however, DNA vaccine is weak immunogen inferior to viral vectors. In recent, heterologous prime-boost vaccination leads DNA vaccines to practical reality. Methods: We assessed prime-boost immunization strategies with a DNA vaccine (minigene, $gB_{498-505}$ DNA) and recombinant vaccinia virus $(vvgB_{498-505})$ expressing epitope $gB_{498-505}$ (SSIEF ARL) of CD8+ T cells specific for glycoprotein B (gB) of herpes simplex virus (HSV). Animals were immunized primarily with $gB_{498-505}$ epitope-expressing DNA vaccine/recombinant vaccinia virus and boosted with alternative vaccine type expressing entire Ag. Results: In prime-boost protocols using vvgBw (recombinant vaccinia virus expressing entire Ag) and $vvgB_{498-505}$, CD8+ T cell-mediated immunity was induced maximally at both acute and memory stages if primed with vvgBw and boosted with $vvgB_{498-505}$ as evaluated by CTL activity, intracellular IFN-staining, and MHC class I tetramer staining. Similarly $gB_{498-505}$ DNA prime-gBw DNA (DNA vaccine expressing entire Ag) boost immunization elicited the strongest CD8+ T cell responses in protocols based on DNA vaccine. However, the level of CD8+ T cell-mediated immunity induced with prime-boost vaccination using DNA vaccine expressing epitope or entire Ag was inferior to those based on vvgBw and $vvgB_{498-505}$. Of particular interest CD8+ T cell-mediated immunity was optimally induced when $vvgB_{498-505}$ was used to prime and gB DNA was used as alternative boost. Especially CD7+ T cell responses induced by such protocol was longer lasted than other protocols. Conclusion: These facts direct to search for the effective strategy to induce optimal CD8+ T cell-mediated immunity against cancer and viral infection.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.293-299
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• 2009

Auxin-binding protein 57 ($ABP_{57}$), a soluble auxin-binding protein, acts as a receptor to activate plasma membrane (PM) $H^+-ATPase$. Here, we report the cloning of abp57 and the biochemical characterization of its protein expressed in E. coli. The analysis of internal amino acid sequences of $ABP_{57}$ purified from rice shoots enabled us to search for the corresponding gene in protein DB of NCBI. Further BLAST analysis showed that rice has four abp57-like genes and maize has at least one homolog. Interestingly, Arabidopsis seems to have no homolog. Recombinant $ABP_{57}$ expressed in E. coli caused the activation of PM $H^+-ATPase$ regardless of the existence of IAA. Scatchard analysis showed that the recombinant protein has relatively low affinity to IAA as compared to natural $ABP_{57}$. These results collectively support the notion that the cloned gene is responsible for $ABP_{57}$.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.391-397
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• 2020

In this study, we used a novel α-L-arabinopyranosidase (AbpBs) obtained from ginsenoside-converting Blastococcus saxobsidens that was cloned and expressed in Escherichia coli BL21 (DE3), and then applied it in the biotransformation of ginsenoside Rb₂ into Rd. The gene, termed AbpBs, consisting of 2,406 nucleotides (801 amino acid residues), and with a predicted translated protein molecular mass of 86.4 kDa, was cloned into a pGEX4T-1 vector. A BLAST search using the AbpBs amino acid sequence revealed significant homology with a family 2 glycoside hydrolase (GH2). The over-expressed recombinant AbpBs in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinopyranose moiety attached to the C-20 position of ginsenoside Rb₂ under optimal conditions (pH 7.0 and 40℃). Kinetic parameters for α-L-arabinopyranosidase showed apparent K_m and V_max values of 0.078 ± 0.0002 μM and 1.4 ± 0.1 μmol/min/mg of protein against p-nitrophenyl-α-L-arabinopyranoside. Using a purified AbpBs (1 ㎍/ml), 0.1% of ginsenoside Rb₂ was completely converted to ginsenoside Rd within 1 h. The recombinant AbpBs could be useful for high-yield, rapid, and low-cost preparation of ginsenoside Rd from Rb₂.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3489-3494
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• 2014

In search of new antileukopenia agents, twenty dithiolopyrrolone derivatives were synthesized and evaluated for their leukocyte-increasing activities in normal mice. Among the synthesized compounds 4-23, compounds 5 and 6 showed significant leukocyte-increasing activity ( p < 0.01), and compounds 4, 9 and 16 had a moderate effect ( p < 0.05). Compound 5 also displayed stronger leukocyte-increasing activity than that of the positive recombinant human granulocyte colony stimulating factor (rhG-CSF). Above all, compound 5 would be a potential antileukopenia agent which deserved further research.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.466-471
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• 2014

Background Bleeding can be a problem in wound debridement. In search for an effective hemostatic agent, we experimented with a chitosan film combined with the recombinant human epidermal growth factor (rh-EGF), hypothesizing that it would achieve effective hemostasis and simultaneously enhance arterial healing. Methods Forty-eight Sprague-Dawley rats were used, and 96 puncture wounds were made. The wounds were divided into the following four groups: treated with sterile gauze, treated with gelatin sponge, treated with chitosan, and treated with chitosan combined with rh-EGF. Immediate hemostasis was evaluated, and arterial healing was observed histologically. Results Groups B, C, and D showed a significant rate of immediate hemostasis as compared to group A (P<0.05), but there were no significant differences among groups B, C, and D. Histologically, only group D showed good continuity of the vessel wall after 1 week. It was the only group to show smooth muscle cell nuclei of the vessel wall. Conclusions We observed that chitosan has an effective hemostatic potential and the mix of rh-EGF and chitosan does not interfere with chitosan's hemostatic capabilities. We also identified enhanced healing of vessel walls when rh-EGF was added to chitosan. Further research based on these positive findings is needed to evaluate the potential use of this combination on difficult wounds like chronic diabetic ulcerations.

• 대한소아치과학회지
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• 제33권2호
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• pp.304-310
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• 2006

본 연구는 치주질환 주요 병인균주 중의 하나인 P. intermedia를 대상으로 하여, 이 균주에서의 hemin 결합 단백질 유전자를 분리하고 염기서열을 결정하기 위하여 수행되었다. 본 연구에서는 약 5,000개의 recombinant colony들을 스크리닝하여 hemin 결합 단백질 유전자를 포함하고 있는 것으로 여겨지는 1개의 클론(pHem1)을 확인하였다. Restriction enzyme mapping 결과 pHem1의 insert DNA의 크기는 약 2.5kb이었으며 P. intermedia chromosomal DNA 내에는 hemin 결합 단백질 유전자가 single copy로 존재하였고, transcript의 크기는 약 1.8kb이었다. 분리한 pHem1 유전자는 1개의 ORF를 가지고 있으며, ORF의 크기는 2,550bp로 약 850개의 아미노산 폴리펩타이드로 구성되어 있다. 또한, pHem1 유전자는 이미 밟혀진 다른 유전자들과 상동성을 보이지 않았다. 본 연구는 P. intermedia에서의 porphyrin생리 및 hemin 획득기전을 분자생물학적으로 규명하는데 있어 중요한 의의가 있으리라 사료된다. 향후 pHem1 유전자의 특성 분석 등이 수행되어야 할 것으로 여겨진다.

• 미생물학회지
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• 제42권2호
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• pp.142-148
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• 2006

본 연구는 다양한 생리활성을 가지고 있는 chitosan oligosaccharides를 효소적 방법으로 생산하기 위한 기초 연구로서, 전통발효식품인 메주에서 chitosan 분해능이 우수한 균주를 분리하였다. 분리한 균주를 형태학적, 생화학적 및 분자생물학적 방법을 이용하여 동정한 결과, Bacillus amyloliquefaciene MJ-1으로 명명하였다. B. amyloliquefaciene MJ-1으로 부터 chitosanase 유전자를 포함하는 1,049 bp DNA 단편을 클로닝하였으며, chitosanase 유전자는 825 염기로서 274 개의 아미노산으로 구성되어 있었고, 예상 분자랸은 30.9 kDa이었다. 클로링한 chitosanase의 homology search 결과, glucoside hydrolase family 46에 속하는 chitosanase로 추정되었다. B. amyloliquefaciene MJ-1 chitosanase 유전자를 E. coli BLR (DE3)에 도입하였으며, 1 mM의 IPTG로 chitosanase 과잉 발현을 유도하고 정제한 후, pH및 온도에 대한 특성을 조사하였다. 효소 활성의 최적 온도는 $60^{\circ}C$이었으며, $80^{\circ}C$에서도 75%의 활성을 나타내었으므로 내열성을 가진 효소로 추정되었다. 한편, 최적 pH는 5.0 이었으며, pH $5{\sim}7$사이에서 80% 이상의 높은 활성을 유지하였다.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.330-338
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• 2019

Chronic infection with intracellular Brucella abortus (B. abortus) in livestock remains as a major problem worldwide. Thus, the search for an ideal vaccine is still ongoing. In this study, we evaluated the protective efficacy of a combination of B. abortus recombinant proteins; superoxide dismutase (rSodC), riboflavin synthase subunit beta (rRibH), nucleoside diphosphate kinase (rNdk), 50S ribosomal protein (rL7/L12) and malate dehydrogenase (rMDH), cloned and expressed into a pMal vector system and $DH5{\alpha}$, respectively, and further purified and applied intraperitoneally into BALB/c mice. After first immunization and two boosters, mice were infected intraperitoneally (IP) with $5{\times}10^4CFU$ of virulent B. abortus 544. Spleens were harvested and bacterial loads were evaluated at two weeks post-infection. Results revealed that this combination showed significant reduction in bacterial colonization in the spleen with a log protection unit of 1.31, which is comparable to the average protection conferred by the widely used live attenuated vaccine RB51. Cytokine analysis exhibited enhancement of cell-mediated immune response as IFN-${\gamma}$ is significantly elevated while IL-10, which is considered beneficial to the pathogen's survival, was reduced compared to control group. Furthermore, both titers of IgG1 and IgG2a were significantly elevated at three and four-week time points from first immunization. In summary, our in vivo data revealed that vaccination with a combination of five different proteins conferred a heightened host response to Brucella infection through cell-mediated immunity which is desirable in the control of intracellular pathogens. Thus, this combination might be considered for further improvement as a potential candidate vaccine against Brucella infection.