• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.502-510
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• 2009

Although the Escherichia coli heat-labile enterotoxin B subunit (LTB) has already been expressed in several different systems, including prokaryotic and eukaryotic organisms, studies regarding the synthesis of LTB into oligomeric structures of pentameric size in the budding yeast Saccharomyces cerevisiae have been limited. Therefore, this study used a functional signal peptide of the amylase 1A protein from rice to direct the yeast-expressed LTB towards the endoplasmci reticulum to oligomerize with the expected pentameric size. The expression and assembly of the recombinant LTB were confirmed in both the cell-free extract and culture media of the recombinant strain using a Western blot analysis. The binding of the LTB pentamers to intestinal epithelial cell membrane glycolipid receptors was further verified using a GM1-ganglioside enzyme-linked inmmunosorbent assay (GM1-ELISA). On the basis of the GM1-ELISA results, pentameric LTB proteins comprised approximately 0.5-2.0% of the total soluble proteins, and the maximum quantity of secreted LTB was estimated to be 3 mg/l after a 3-day cultivation period. Consequently, the synthesis of LTB monomers and their assembly into biologically active aligomers in a recombinant S. cerevisiae strain demonstrated the feasibility of using a GRAS microorganism-based adjuvant, as well as the development of carriers against mucosal disease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.174-180
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• 2016

In this study, the effects of fermented goat milk (F-GM) on immunological activity and physical strength were examined. Splenocytes obtained from mice administered with F-GM showed increased responsinveness to mitogens, concanavalin-A (ConA), and lipopolysaccharide (LPS). Treatment with F-GM also significantly augmented production of interleukin (IL)-2 and interferon (IFN)-${\gamma}$, but not IL-4 or IL-10 from ConA-stimulated splenocytes. The activity of F-GM administration to enhance production of IL-2 and IFN-${\gamma}$ was confirmed based on mRNA expression of these cytokines by reverse transcription polymerase chain reaction. After immunization with keyhole limpet hemocyanin (KLH, 20 mg/mouse), mice administered F-GM showed significantly higher antibody titers against KLH than those of phosphate-buffered saline-treated mice, and showed the highest titer 5 weeks after KLH immunization. Analysis for determining isotypes of antibodies revealed that administration of F-GM elicited KLH-specific antibody titers of IgG1, IgG2a, and IgM. In a delayed type hypersensitivity (DTH) test carried out 7 weeks after the primary immunization, F-GM-treated mice showed a higher DTH reaction than the control mice. Furthermore, the swimming test found that administration of F-GM significantly increased swimming time. These results suggest that administration of F-GM enhances not only immune responses against antigens but also physical strength.

• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.231-237
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• 2009

Purpose: Cytolethal distending toxin (CDT) is a family of heat-labile cytotoxins produced by several gram-negative mucosa-associated pathogens, including Aggregatibacter actinomycetemcomitans. CDT is well known to be capable of inducing growth arrest, morphological alterations, and eventually death in various cells. CDT belongs to a tripartite $AB_2$ toxin (CdtB: the enzymatic A subunit; CdtA and CdtC: the heterodimeric B subunit). Previous studies proposed that CdtA and CdtC together bind to a cell surface receptor and glycolipids act as a receptor for A. actinomycetemcomitans CDT (AaCDT). In this study, recombinant CdtA and CdtC proteins of AaCDT were co-expressed in a bacterial expression system and tested for their affinity for $GM_1$ ganglioside. Methods: The genes for CdtA and CdtC from A. actinomycetemcomitans Y4 were utilized to construct the expression vectors, pRSET-cdtA and pET28a-cdtC. Both CdtA and CdtC proteins were expressed in Escherichia coli BL21(DE3) and then purified using hexahistidine (His6) tag. The identity of purified protein was confirmed by anti-His6 antibody and monoclonal anti-CdtA antibody. Furthermore, the affinity of recombinant protein to $GM_1$ ganglioside was checked through ELISA. Results: Recombinant CdtA and CdtC proteins were expressed as soluble proteins and reacted to anti-His6 and monoclonal anti-CdtA antibodies. ELISA revealed that purified soluble CdtA-CdtC protein bound to $GM_1$ ganglioside, while CdtA alone did not. Conclusions: Co-expression of CdtA and CdtC proteins enhanced the solubility of the proteins in E. coli, leading to convenient preparation of active CdtA-CdtC, a critical material for the study of AaCDT pathogenesis.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.815-827
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• 2020

The epidermal growth factor (EGF) transgenic soybean was developed and biosynthesis of human epidermal growth factor (hEGF) in soybean seeds was confirmed. Also, EGF transgenic soybean were found to contain a herbicide resistance selectable marker by introduction of phosphinothricin acetyltransferase (PAT) gene from the Streptomyces hygroscopicus. For biosafety assessment, the EGF transgenic soybean expressing the EGF biosynthesis gene EGF and herbicide resistant gene PAT was tested to determine effects on survival of Cyprinus carpio, commonly used as a model organism in ecotoxicological studies. C. carpio was fed 100% ground soybean suspension, EGF soybean or non-genetically modified (GM) counterpart soybean (Gwangan). Gene expression of EGF soybean was confirmed by PCR and ELISA to have EGF/PAT. Feeding test showed that no significant differences in cumulative immobility or abnormal response between C. carpio samples fed on EGF soybean and non-GM counterpart soybean. The 48 h-EC50 values of the EGF and non-GM soybean were 1,688 mg·L-1 (95% confidence limits: 1,585 - 1,798 mg·L-1) and 1,575 mg·L-1 (95% confidence limits: 1,433 - 1,731 mg·L-1), respectively. The soybean NOEC (no observed effect concentration) value for C. carpio was suggested to be 625 mg·L-1. We concluded that there was no significant difference in toxicity for non-target organisms (C. carpio) between the EGF soybean and non-GM counterparts.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.205-214
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• 2016

A drought-tolerant transgenic rice (Agb0103) was developed using a pepper methionine sulfoxide reductase (CaMsrB2) under the control of rice Rab21 promoter with a selection marker, the phosphinothricin acetyltransferase (PAT) gene. Commercialization of genetically modified (GM) crops will require the evaluation of risks associated with the release of GM crops. With the potential problems associated to GM crops safety testing, the investigation of their effects on non-target organisms is necessary for environmental risk research. This study was carried out to assess acute toxicity of a GM crop using the water flea (Daphnia magna) for non-target organism risk evaluation. The effect of acute toxicity on Daphnia magna of Agb0103 rice and a non-GM rice, Ilmibyeo, were investigated at different concentrations (0, 625, 1,250, 2,500, 5,000, and 10,000 mg/L). The Agb0103 rice used for the test was confirmed to express the CaMsrB2/PAT gene by the PCR and ELISA. Daphnia magna feeding tests showed no significant differences in cumulative immobility or abnormal response with either Agb0103 rice or non-GM rice. The 48hr-EC50 values showed no difference between Agb0103 rice (2243 mg/L) and non-GM rice (2694 mg/L). These results suggest that there is no significant difference in toxicity to Daphnia magna between Agb0103 rice and its non-GM counterpart.

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1044-1050
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• 2014

Since there is no consensus about the most reliable assays to detect invasive aspergillosis from samples obtained by minimally invasive or noninvasive methods, we compared the efficacy of an enzyme-linked immunosorbent assay (ELISA) for galactomannan (GM) detection and quantitative real-time PCR assay (qRT-PCR) for the diagnosis of invasive pulmonary aspergillosis. Neutropenic, male Sprague-Dawley rats (specific pathogen free; 8 weeks old; weight, $200{\pm}20g$) were immunosuppressed with cyclophosphamide and infected with Aspergillus fumigatus intratracheally. Tissue and whole blood samples were harvested on days 1, 3, 5, and 7 post-infection and examined with GM ELISA and qRT-PCR. The A. fumigatus DNA detection sequence was detected in the following number of samples from 12 immunosuppressed, infected rats examined on the scheduled days: day 1 (0/12), day 3 (0/12), day 5 (6/12), and day 7 (8/12) post-infection. The sensitivity and specificity of the qRT-PCR assay was 29.2% and 100%, respectively. Receiver operating characteristic curve (ROC) analysis indicated a Ct (cycle threshold) cut-off value of 15.35, and the area under the curve (AUC) was 0.627. The GM assay detected antigen in sera obtained on day 1 (5/12), day 3 (9/12), day 5 (12/12), and day 7 (12/12) post-infection, and thus had a sensitivity of 79.2% and a specificity of 100%. The ROC of the GM assay indicated that the optimal Ct cut-off value was 1.40 (AUC, 0.919). The GM assay was more sensitive than the qRT-PCR assay in diagnosing invasive pulmonary aspergillosis in rats.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.268-274
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• 2009

Porphyromonas gingivalis, the gram-negative anaerobic oral bacterium, initiates periodontal disease by binding to saliva-coated oral surface. The cholera toxin B subunit (CTB) genetically linked to FimA1 (1-200 aa) or FimA2 (201-337 aa) of the P. gingivalis fimbrial antigen were introduced into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation method. The integration of CTB-FimA1 or CTB-FimA2 fusion genes were confirmed in the chromosome of transformed leaves by genomic DNA PCR amplification method. Synthesis and assembly of the CTB-FimA fusion proteins into oligomeric structures with pentamer size was detected in transformed tuber extracts by immunoblot analysis. The binding activities of CTB-FimA fusion proteins to intestinal epithelial cell membrane receptors were confirmed by GM1-ganglioside enzyme-linked immunosorbent assay (GM1-ELISA). The ELISA showed that the expression levels of the CTB-FimA1 or CTB-FimA2 fusion proteins were 0.0019, 0.002% of the total soluble protein in transgenic tuber tissues, respectively The synthesis of CTB-FimA monomers and their assembly into biologically active oligomers in transformed potato tuber tissues demonstrates the feasibility of using edible plants for the production of enterocyte targeted fimbrial antigens that could elicit mucosal immune responses.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.791-802
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• 2020

Theoredoxin (TRX) transgenic soybeans were developed using the human Theoredoxin gene under the control of the ��-conglycinin promoter with a selection marker, the phosphinothricin acetyltransferase (PAT) gene. This study was done to assess the acute toxicity of a genetically modified (GM) soybean using the fresh water planktonic crustacean Daphnia magna. The acute toxicity effect of the TRX soybean and non-GM soybean (Gwangan) on D. magna was investigated at different concentrations (0, 156, 313, 625, 1,250, 2,500, and 5,000 mg·L-1). The TRX soybean used for the test was confirmed to express the TRX/PAT genes by PCR and enzyme-linked immunosorbent assay (ELISA). D. magna feeding tests showed no significant differences in the cumulative immobility or an abnormal response with either the TRX soybean or non-GM soybean. The feeding study showed a similar abnormal response and cumulative immobility of the D. magna between the TRX soybean and Gwangan treatments. Additionally, the 48 h-EC50 values for the TRX and Gwangan soybeans were 755.6 and 778 mg·L-1, respectively. The soybean NOEC (no observed effect concentration) value for D. magna was suggested to be 156 mg·L-1. These results suggest that there is no significant difference in toxicity to Daphnia magna between the TRX soybean and its non-GM counterpart.

• The Journal of Pediatrics of Korean Medicine
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• v.28 no.2
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• pp.23-39
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• 2014

Objectives PRAL (Prunus armniaca Linne Var) is a herbal formula in Oriental Medicine, known for its anti-inflammatory and anti-allergenic properties. However, its mechanism of action and the cellular targets have not yet been found enough. The purpose of this study is to investigate the effects of PRAL on Th2 cytokines expression in MC/9 mast cells. Methods The effect of PRAL was analyzed by ELISA, Real-time PCR, Western blot in MC/9 mast cells. mRNA levels of GM-CSF, IL-4, IL-5, IL-6, IL-13, TNF-${\alpha}$ were analyzed with Real-time PCR. Levels of IL-13, MIP-$1{\alpha}$ were measured using enzyme-linked immunosorbent assays (ELISA). NFAT, AP-1 and NF-${\kappa}B$ p65 were examined by Western blot analysis. Results PRAL inhibited GM-CSF, IL-4, IL-5, IL-6, IL-13, TNF-${\alpha}$ mRNA expression in a dose dependent manner. GM-CSF, IL-4, IL-5 mRNA expression were inhibited significantly in comparison to DNP-IgE control group at concentration of 100 ${\mu}g/ml$ and IL-6, IL-13, TNF-${\alpha}$ mRNA expression were inhibited at concentration of 50 ${\mu}g/ml$, 100 ${\mu}g/ml$. PRAL also inhibited the IL-13, MIP-$1{\alpha}$ production significantly in comparison to DNP-IgE control group in a dose dependent manner. IL-13 production was inhibited at a concentration of 200 ${\mu}g/ml$, 400 ${\mu}g/ml$ and MIP-$1{\alpha}$ was inhibited at a concentration of 100 ${\mu}g/ml$, 200 ${\mu}g/ml$, 400 ${\mu}g/ml$. Western blot analysis of transcription factors involving Th2 cytokines expression revealed prominent decrease of the mast cell specific transcription factors including NFAT-1, c-Jun as well as NF-${\kappa}B$ p65 but not NFAT-2 and c-Fos. Conclusion These results indicate that PRAL has the effect of suppressing Th2 cytokines production in the MC/9 mast cells. These data represent that PRAL potentiates therapeutic activities to the allergic disease by regulating Th2 cytokines in the MC/9 mast cells.

• Korean Journal of Head & Neck Oncology
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• v.19 no.1
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• pp.25-33
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• 2003

Background and Objectives: The Herpes Simplex type 2 Defective Infectious Single Cycle virus (DISC virus) is attenuated virus originally produced as viral vaccines but are also efficient gene transfer vehicle. The main goals of this study were to examine the efficiencies of the gene transfer using DISC vectors for various head and neck squamous cell carcinoma cell lines and to evaluate the efficacy of vaccination with DISC virus carrying a immunomodulatory genes (GM-CSF) as cancer therapy in a organotopic oral cavity squamous cell cancer model. Materials and Methods : We determinated the gene transfer efficiency of DISC virus by x-gal stain method and proved gene and protein expression of DISC-GMCSF transfected SCCVII cells by RT-PCR and ELISA method. Also we evaluated the ex vivo vaccination effects of SCCVII/GMCSF (DISC-GMCSF transfected SCCVII vaccine) vaccine on preventing the recurrence of micro-residual tumor. After the vaccination of SCCVII/GMCSF, specific cytotoxic T-cell responses was evaluated by CTL assay. Results: At an MOI of 10 DISC virus showed 64-88% of transfection rates in various head and neck squamous cancer cell lines. SCCVII cells transduced by DISC virus vector (MOI=10) carrying the GM-CSF gene, produced 4.5 nanogram quantities of GM-CSF per $10^6$ cells. In vivo vaccination using tumor cells transduced ex vivo with DISC-GMCSF resulted in better protection rate against subsequent tumor recurrence in organotopic oral cavity cancer model. Although tumor free survival rate was not statistically significantly increased in vaccination group (p=0.078), tumor specific cytotocic T-cell responses were significantly increased in SCCVII/GMCSF vaccination group. Conclusion: These data demonstrate that; 1) The DISC virus vector is capable of efficient gene transfer to various head and neck squamous cancer cell lines, 2) GM-CSF secreting genetically modified tumor vaccine (SCCVII/GMCSF) efficiently protected against tumor recurrence in organotopic micro-residual oral cavity cancer model and produced tumor specific cytotoxic T-cell response. DISC virus-mediated, cytokine gene transfer may prove to be useful as a clinical therapy for head and neck cancers.