• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.337-345
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• 2014

Pichia pastoris is one of the most widely used expression systems for the secretory expression of recombinant proteins. The secretory expression in P. pastoris usually makes use of the prepro $MAT{\alpha}$ sequence from Saccharomyces cerevisiae, which has a dibasic amino acid cleavage site at the end of the signal sequence. This is efficiently processed by Kex2 protease, resulting in the secretion of high levels of proteins to the medium. However, the proteins that are having the internal accessible dibasic amino acids such as KR and RR in the coding region cannot be expressed using this signal sequence, as the protein will be fragmented. We have identified a new signal sequence of 18 amino acids from a P. pastoris protein that can secrete proteins to the medium efficiently. The PMT1-gene-inactivated P. pastoris strain secretes a ~30 kDa protein into the extracellular medium. We have identified this protein by determining its N-terminal amino acid sequence. The protein secreted has four DDDK concatameric internal repeats. This protein was not secreted in the wild-type P. pastoris under normal culture conditions. We show that the 18-amino-acid signal peptide at the N-terminal of this protein is useful for secretion of heterologous proteins in Pichia.

• 대한한방내과학회지
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• 제27권1호
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• pp.138-148
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• 2006

Objectives: This study was designed to investigate the effects of Injinchunggan-tang(Yinchenqinggan-tang) on expression of angiogenic factors in HepG2 cells. Materials and Methods : The mRNA expression levels and protein secretion levels of angiogenic factors were measured using quantitative RT-PCR, Western blot and ELISA assay respectively in Injinchunggan-tang-treated and untreated HepG2 cells. Results : Injinchunggan-tang(Yinchenqinggan-tang) reduced mRNA expression levels and protein secretion levels of angiogenic factors, especially VEGF, bFGF and $TGF{\beta}1$ in HepG2 cells. Conclusion: Results indicate that Injinchunggan-tang (Yinchenqinggan-tang) inhibits expression of angiogenic factors in HepG2 cells. Further, results suggest that Injinchunggan-tang (Yinchenqinggan-tang) inhibits angiogenic effects in HCC.

• BMB Reports
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• 제46권4호
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• pp.213-218
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• 2013

Members of the colony stimulating factor cytokine family play important roles in macrophage activation and recruitment to inflammatory lesions. Among them, granulocyte-macrophage colony stimulating factor (GM-CSF) is known to be associated with immune response to mycobacterial infection. However, the mechanism through which Mycobacterium tuberculosis (MTB) affects the expression of GM-CSF is poorly understood. Using PMA-differentiated THP-1 cells, we found that MTB infection increased GM-CSF mRNA expression in a dose-dependent manner. Induction of GM-CSF mRNA expression peaked 6 h after infection, declining gradually thereafter and returning to its basal levels at 72 h. Secretion of GM-CSF protein was also elevated by MTB infection. The increase in mRNA expression and protein secretion of GM-CSF caused by MTB was inhibited in cells treated with inhibitors of p38 MAPK, mitogen-activated protein kinase kinase (MEK-1), and PI3-K. These results suggest that up-regulation of GM-CSF by MTB is mediated via the PI3-K/MEK1/p38 MAPK-associated signaling pathway.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.379-384
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• 2004

Fibroblast growth factor-2 (FGF-2) is known to modulate numerous cellular functions in various cell types, including cell proliferation, differentiation, survival, adhesion, migration, and motility, and also in processes such as wound healing, angiogenesis, and vasculogenesis. FGF-2 regulates the expression of several molecules thought to mediate critical steps during angiogenesis. This study examines the mechanisms underlying FGF-2-induced cell migration, using human umbilical vein endothelial cells (HUVECs). FGF-2 induced the nondirectional and directional migration of endothelial cells, which are inhibited by MMPs and plasmin inhibitors, and induced the secretion of matrix metalloproteinase-3 (MMP3) and MMP-9, but not MMP-l and MMP-2. FGF-2 also induced the secretion of the tissue inhibitor of metalloproteinase-l (TIMP-I), but not of TIMP- 2. Also, the pan-PKC inhibitor inhibited FGF-2-induced MMP-9 secretion. It is, therefore, suggested that FGF-2 induces the migration of cultured endothelial cells by means of increased MMPs and plasmin secretion. Furthermore, FGF-2 may increase MMP-9 secretion by activating the PKC pathway.

• 대한한방소아과학회지
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• 제28권2호
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• pp.56-71
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• 2014

Objectives In this study, the author tried to investigate whether piryongbang-gamgil-tang (PGGT) significantly affect in vitro airway mucin secretion, PMA- or EGF- or TNF-${\alpha}$-induced MUC5AC mucin production / gene expression from human airway epithelial cells and increase in airway epithelial mucosubstances and hyperplasia of tracheal goblet cells of rats. Materials and Methods For in vitro experiment, confluent RTSE cells were chased for 30 min in the presence of PGGT to assess the effect of PGGT on mucin secretion by enzyme-linked immunosorbent assay (ELISA). Also, effect of PGGT on PMA- or EGFor TNF-${\alpha}$-induced MUC5AC mucin production and gene expression from human airway epithelial cells (NCI-H292) were investigated. Confluent NCI-H292 cells were pretreated for 30 min in the presence of PGGT and treated with PMA (10 ng/ml) or EGF (25 ng/ml) or TNF-${\alpha}$ (0.2 nM) for 24 hrs, to assess both effect of PGGT on PMA- or EGF- or TNF-${\alpha}$-induced MUC5AC mucin production by ELISA and gene expression by reverse transcription-polymerase chain reaction (RT-PCR). For in vivo experiment, the author induced hypersecretion of airway mucus and goblet cell hyperplasia by exposure of rats to $SO_2$ during 3 weeks. Effect of orally-administered PGGT during 2 weeks on increase in airway epithelial mucosubstances from tracheal goblet cells of rats and hyperplasia of goblet cells were assesed by using histopathological analysis after staining the epithelial tissue with alcian blue. Possible cytotoxicities of PGGT in vitro were assessed by examining LDH release from RTSE cells and the rate of survival and proliferation of NCI-H292 cells. In vivo liver and kidney toxicities of PGGT were evaluated by measuring serum GOT/GPT activities and serum BUN/creatinine concentrations of rats after administering PGGT orally. Results (1) PGGT did not affect in vitro mucin secretion from cultured RTSE cells. (2) PGGT significantly inhibited PMA-, EGF-, and TNF-${\alpha}$-induced MUC5AC mucin productions and the expression levels of MUC5AC mRNA from NCI-H292 cells. (3) PGGT decreased the amount of intraepithelial mucosubstances and showed the tendency of expectorating airway mucus already produced. (4) PGGT increased LDH release from RTSE cells. However, PGGT did not show in vivo liver and kidney toxicities and cytotoxicity to NCI-H292 cells. Conclusion The result from this study suggests that PGGT can regulate the production and gene expression of airway mucin observed in diverse respiratory diseases accompanied by mucus hypersecretion and do not show in vivo toxicity to liver and kidney functions after oral administration. Effect of PGGT with their components should be further studied using animal experimental models that reflect the diverse pathophysiology of respiratory diseases through future investigations.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.1977-1988
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• 2015

β-1,3-glucanosyltransferases play essential roles in cell wall biosynthesis in yeast. Kluyveromyces lactis has six putative β-1,3-glucanosyltransferase genes. KlGAS1-1 and KlGAS1-2 are homologs of Saccharomyces cerevisiae gene GAS1. RT-qPCR indicated the transcription level of KlGAS1-1 was significantly reduced while heterologous protein (thermostable xylanase B) secretion was enhanced during medium optimization. To evaluate if these two events were related, and to improve xylanase B secretion in K. lactis, we constructed KlGAS1-1 and KlGAS1-2 single deletion strains and double deletion strain, respectively. KlGAS1-1 gene deletion resulted in the highest xylanase B activity among the three mutants. Only the double deletion strain showed morphology similar to that of the GAS1 deletion mutant in S. cerevisiae. The two single deletion strains differed in terms of cell wall thickness and xylanase B secretion. Transcription levels of β-1,3-glucanosyltransferase genes and genes related to protein secretion and transport were assayed. The β-1,3-glucanosyltransferase genes displayed transcription complementation in the cell wall synthesis process. KlGAS1-1 and KlGAS1-2 affected transcription levels of secretion- and transport-related genes. Differences in protein secretion ratio among the three deletion strains were associated with changes of transcription levels of secretion- and transport-related genes. Our findings indicate that KlGAS1-1 deletion is an effective tool for enhancing industrial-scale heterologous protein secretion in K. lactis.

• Journal of Microbiology and Biotechnology
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• 제27권11호
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• pp.1999-2009
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• 2017

The secretion efficiency of a protein in a Sec-type secretion system is mainly determined by an N-terminal signal peptide and its combination with its cognate protein. Five signal peptides, namely, two synthetic Sec-type and three Bacillus licheniformis alpha-amylase-derived signal peptides, were compared for periplasmic expression of the human growth hormone (hGH) in E. coli. Based on in silico predictions on the signal peptides' cleavage efficiencies and their corresponding mRNA secondary structures, a number of amino acid substitutions and silent mutations were considered in the modified signal sequences. The two synthetic signal peptides, specifically designed for hGH secretion in E. coli, differ in their N-terminal positively charged residues and hydrophobic region lengths. According to the mRNA secondary structure predictions, combinations of the protein and each of the five signal sequences could lead to different outcomes, especially when accessibility of the initiator ATG and ribosome binding sites were considered. In the experimental stage, the two synthetic signal peptides displayed complete processing and resulted in efficient secretion of the mature hGH in periplasmic regions, as was demonstrated by protein analysis. The three alpha-amylase-derived signal peptides, however, were processed partially from their precursors. Therefore, to achieve efficient secretion of a protein in a heterologous system, designing a specific signal peptide by using a combined approach of optimizations of the mRNA secondary structure and the signal peptide H-domain and cleavage site is recommended.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1236-1241
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• 2007

Five fusion proteins between Z domains derived from Staphylococcal Protein A and Green Fluorescent Protein or Human Proinsulin were produced on the periplasm of Escherichia coli. The effects of the molecular weight and amino acid composition of the translocated peptide, culture medium composition, and growth phase of the bacterial culture were analyzed regarding the expression and periplasmic secretion of the recombinant proteins. It was found that secretion was not affected by the size of the translocated peptide (17-42 kDa) and that the highest periplasmic production values were obtained on the exponential phase of growth. Moreover, the highest periplasmic values were obtained in minimal medium, showing the relevance of the culture medium composition on secretion. In silico prediction analysis suggested that with respect to the five proteins used in this study, those that are prone to form ${\alpha}$-helix structures are more translocated to the periplasm.

• 한국약용작물학회지
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• 제18권5호
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• pp.291-297
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• 2010

Liriope platyphylla has been though as an useful medical plant to improve the cough, sputum, neurodegenerative disorders, obesity, and diabetes in Korea and China from old times. In order to investigate the effects of Liriope platyphylla on expression and secretion of nerve growth factor (NGF), the mRNA expression and protein secretion were detected in the neuronal cell (B35) and neuroglial cell (C6) cultured with three differences concentration (5%, 10%, 15%) of Liriope platyphylla. In MTT assay and FACS anslysis, the some death of some B35 and C6 cells were observed in 15% extract-treated group, while other groups did not induce the death. Also, the mRNA expression of NGF were significantly increased in 5% and 10% extracts treated-group. Furthermore, the NGF protein concentration in supernatant collected from cultured cells showed the very similar pattern with mRNA expression. In order to verify the activity of secreted NGF, the culture supernatant collected from B35 and C6 cells cultured with Liriope platyphylla extracts for 24 hrs were treated into undifferentiated PC12 cells, and the differentiation level of PC12 cell were also observed with microscopes. The differentiation level of PC12 cell were significantly increased depend on the dose of extract. Therefore, these results suggested that the water extracts of Liriope platyphylla may contribute the regulation of NGF expression and secretion in the neuronal cell and be considered as an excellent candidate for a neurodegenerative disease-therapeutic drug.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제39권3호
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• pp.112-119
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• 2013

Objectives: This study investigated the question of whether adenoviral magnetofection can be a suitable method for increasing the efficacy of gene delivery into bone marrow stromal cell (BMSC) and for generation of a high level of bone morphogenic protein (BMP) secretion at a minimized viral titer. Materials and Methods: Primary BMSCs were isolated from C57BL6 mice and transduced with adenoviral vectors encoding ${\beta}$ galactosidase or BMP2 and BMP7. The level of BMP secretion, activity of osteoblast differentiation, and cell viability of magnetofection were measured and compared with those of the control group. Results: The expression level of ${\beta}$ galactosidase showed that the cell transduction efficiency of AdLacZ increased according to the increased amount of magnetic nanoparticles. No change in cell viability was observed after magnetofection with 2 ${\mu}L$ of magnetic nanoparticle. Secretion of BMP2 or BMP7 was accelerated after transduction of AdBMP2 and 7 with magnetofection. AdBMP2 adenoviral magnetofection resulted in up to 7.2-fold higher secretion of BMP2, compared with conventional AdBMP2-transduced BMSCs. Magnetofection also induced a dramatic increase in secretion of BMP7 by up to 10-fold compared to the control. Use of only 1 multiplicity of infection (moi) of magnetofection with adenoviral transduction of AdBMP2 or AdBMP7 resulted in significantly higher transgene expression compared to 20 moi of conventional adenoviral transduction. Conclusion: Magnetic particle-mediated gene transudation is a highly efficient method of gene delivery to BMSCs. Magnetofection can lower the amount of viral particles while improving the efficacy of gene delivery.