• Molecules and Cells
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• v.39 no.3
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• pp.217-228
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• 2016

To generate a biobetter that has improved therapeutic activity, we constructed scFv libraries via random mutagenesis of several residues of CDR-H3 and -L3 of hu4D5. The scFv clones were isolated from the phage display libraries by stringent panning, and their antiproliferative activity against HER2-positive cancer cells was evaluated as a primary selection criterion. Consequently, we selected AH06 as a biobetter antibody that had a 7.2-fold increase in anti-proliferative activity ($IC_{50}$: 0.81 nM) against the gastric cancer cell line NCI-N87 and a 7.4-fold increase in binding affinity ($K_D$: 60 pM) to HER2 compared to hu4D5. The binding energy calculation and molecular modeling suggest that the substitution of residues of CDR-H3 to W98, F100c, A101 and L102 could stabilize binding of the antibody to HER2 and there could be direct hydrophobic interactions between the aromatic ring of W98 and the aliphatic group of I613 within HER2 domain IV as well as the heavy and light chain hydrophobic interactions by residues F100c, A101 and L102 of CDR-H3. Therefore, we speculate that two such interactions were exerted by the residues W98 and F100c. A101 and L102 may have a synergistic effect on the increase in the binding affinity to HER2. AH06 specifically binds to domain IV of HER2, and it decreased the phosphorylation level of HER2 and AKT. Above all, it highly increased the overall level of p27 compared to hu4D5 in the gastric cancer cell line NCIN82, suggesting that AH06 could potentially be a more efficient therapeutic agent than hu4D5.

• Proceedings of the Ginseng society Conference
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• 1990.06a
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• pp.168-174
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• 1990

This study was focused on the characterization of mitochondrial DNA (mtDNA) for molecular genetically approach of energy Production related mechanism in Panax Ein.fend. The simple and efficient method of mtDNA isolation from ginseng has been developed by modification of recently advanced methods. This procedure can successfully apply to mtDNA isolation of several plants. MtDNA of etiolated shoot and one-year root were digested with restriction endonucleases, but that of 6-year root not Any difference was not observed in the restriction endonuclease digestion patterns among the ginseng variants. Molecular size of ginseng mtDNA was estimated at least 159 kb by the restriction endonuclease fragment analysis. The 4.5 kb extra band at the lane of EcoRll treatment could be observed in restriction patterns digested with the methylation sensitive endonucleases, BstN 1 and EcoRll. For construction of mitochondrial genomic library of ginseng, mtDNA was partially digested with EcoRl, and packaged with EMBL4 phage vector Genomic library was screened and purified for further research including restricttion mapping of ginseng mtDNA, and cloning of the genes. The gene of ATP synthase A subunit was cloned koto the purified EMBL4 library clone No. 16. Now, clone No. 16 is subcloned for structure gene sequence analysis.

• Journal of Microbiology and Biotechnology
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• v.21 no.1
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• pp.50-54
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• 2011

This study's objective was to determine the prevalence of Salmonella spp. in pigs and their farm environments in Korea, and to investigate the relationship between the strains based on their phenotypic and genotypic characteristics. A total of 36 Salmonella spp. were isolated in this study: 18 isolates from 492 pigs (3.7%) and 18 isolates from 418 (4.3%) farmhouse environmental samples from 16 different pig farms. Of the Salmonella strains isolated from the numerous environmental samples, the highest prevalence was observed in slurry or manure, followed by partitions, farmer's hands, floors, water/nipples, ventilation sources, and feed, respectively. All the Salmonella isolates originating from different farms were genetically distinct. In three farms, however, identical phage types and pulse-field gel electrophoresis patterns were observed among Salmonella isolates from pig feces and environmental samples. This study suggests that environments contaminated with Salmonella could pose an infection risk to pigs on pig farms.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3071-3075
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• 2012

Human ${\alpha}$-synuclein is the major component of the protein aggregates known as Lewy bodies or Lewy neurites, which define the intracellular lesions of Parkinson's disease. Despite extensive efforts, the physiological function of ${\alpha}$-synuclein has not yet been elucidated in detail. As an approach to defining its function, proteins that interacted with ${\alpha}$-synuclein were screened in phage display assays. The SNARE protein vesicle t-SNARE-interacting protein homologous 1B (VTI1B) was identified as an interacting partner. A selective interaction between ${\alpha}$-synuclein and VTI1B was confirmed by coimmunoprecipitation and GST pull-down assays. VTI1B and ${\alpha}$-synuclein were colocalized in N2a neuronal cells, and overexpression of ${\alpha}$-synuclein changed the subcellular localization of VTI1B to be more dispersed throughout the cytosol. Considering the role played by VTI1B, ${\alpha}$-synuclein is likely to modulate vesicle trafficking by interacting with a SNARE complex.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.59-64
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• 2018

Bacteriophages of Acidovorax citrulli, the causal agent of bacterial fruit blotch, were isolated from 39 watermelon, pumpkin, and cucumber leaf samples collected from various regions of Korea and tested against 18 A. citrulli strains. Among the six phages isolated, ACP17 forms the largest plaque, and exhibits the morphology of phages in the Myoviridae family with a head diameter of $100{\pm}5nm$ and tail length of $150{\pm}5nm$. ACP17 has eclipse and latent periods of $25{\pm}5min$ and $50{\pm}5min$, respectively, and a burst size of 120. The genome of ACP17 is 156,281 base pairs with a G + C content of 58.7%, 263 open reading frames, and 4 transfer RNA genes. Blast search and phylogenetic analysis of the major capsid protein showed that ACP17 has limited homology to two Stentrophomonas phages, suggesting that ACP17 is a new type of Myoviridae isolated from A. citrulli.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2075-2088
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• 2017

Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobial-resistant Salmonella, new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella, the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella-specific phages, the effectiveness of Salmonella-specific phages as biocontrol agents, and the prospective use of Salmonella-specific phages in the food industry.

• YAKHAK HOEJI
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• v.50 no.1
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• pp.33-39
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• 2006

We have previously reported the minimum criteria that can be applied to evaluate efficacy and safety of a DNA vaccine with use of Streptococcus pneumoniae DNA vaccine (SPDNA). The SPDNA was formulated by inserting the DNA sequences that are codons specific for the carbohydrate epitope in the capsule of S. penumoniae by phage display peptide library. Administration of the SPDNA into mice induced both humoral and cell-mediated immunities. The induction was protective even in the absence of CD4+ T lymphocyte in mice. Profiles of cytokine and isotyping of antibody displayed tendency of the Th1. In continuation of these studies, we examined if the efficacy of the SPNDA was provoked by the peptide recognized by codons specific for the capsule. Results showed that the peptide vaccine formulae (SPP) induced protective antibody in mice as did the SPDNA. Involvement of the cell-mediated immunity was also determined. Possible side effects of autoimmune diseases such as myositis and C3a production and tumor-formation were undetectable in mice given 7 times of SPDNA vaccination during entire of 92 days. Even after the frequent immunization, immunogenicity of the SPDNA was observed as determined for antibody production, suggesting that there was no immunotolerance provoked. All together, these examining factors would be applied to measurement of a DNA vaccine safety regarding the immunopathological aspect.

• BMB Reports
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• v.37 no.3
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• pp.356-361
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• 2004

To develop a simplified method that can rapidly prepare DNA microarray probes in a massive scale, a lambda phage genomic DNA-fragments library was constructed for the microarray-probes collection. Four methods of DNA band recovery from the first PCR products were tested and compared. The DNA microarray probes were collected by a novel method of nested PCR that was mediated by gel isolation of the first PCR products. This method was named GIN-PCR. The probes that were prepared by this GIN-PCR technique were used as subjects to fabricate a DNA microarray. The results showed that a wooden toothpick was superior to the other 3 methods, since this technique can steadily transfer the DNA bands as the template of the second PCR after the first PCR. A group of probes were successfully collected and DNA microarrays were constructed using these probes. Hybridization results demonstrated that this technique of DNA recovery and probe preparation was rapid, efficient, and effective. We developed a cost-effective and less labor-intensive method for DNA microarray probe preparation by nested PCR that is mediated by wooden toothpick transfer of the DNA bands in the gel after electrophoresis.

• Biomedical Science Letters
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• v.10 no.2
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• pp.65-73
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• 2004

I report that single-stranded antisense as a part of large circular (LC-) genomic DNA of recombinant M13 phage exhibits enhanced stability, sequence specific antisense activity, and no need for target site search. A cDNA fragment (708 bp) of rat TNF-$\alpha$ was inserted into a phagemid vector, and TNF-$\alpha$ antisense molecules (TNF$\alpha$-LCAS) were produced as single-stranded circular DNA. When introduced into a rat monocyte/macrophage cell line, WRT7/P2, TNF$\alpha$-LCAS was able to ablate LPS-induced TNF-$\alpha$ mRNA to completion. The antisense effect of TNF$\alpha$-LCAS was shown to be sequence-specific because expressions of three control genes ($\beta$-actin, GAPDH and IL-1$\beta$) were not significantly altered by the antisense treatment. Further, TNF$\alpha$-LCAS was found to be highly efficacious as only 0.1 $\mu$g (0.24 nM) of TNF$\alpha$-LCAS was sufficient to block TNF-$\alpha$ expression in 1$\times10^5$ WRT7/P2 cells. I have also observed specific antisense activity in reduction of NF-$\kappa$B gene expression. The results suggest that an antisense sequence as a part of single-stranded circular genomic DNA has a specific antisense activity.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.821-827
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• 2010

Gene delivery that provides targeted delivery of therapeutic genes to the cells of a lesion enhances therapeutic efficacy and reduces toxic side effects. This process is especially important in cancer therapy when it is advantageous to avoid unwanted damage to healthy normal cells. Incorporating cancer-specific ligands that recognize receptors overexpressed on cancer cells can increase selective binding and uptake and, as a result, increase targeted transgene expression. In this study, we investigated whether a peptide capable of homing to hepatocellular carcinoma (HCC) could facilitate targeted gene delivery by cationic liposomes. This homing peptide (HBP) exhibited selective binding to a human hepatocarcinoma cell line, HepG2, at a concentration ranging from 5 to 5,000 nM. When conjugated to a cationic liposome, HBP substantially increased cellular internalization of plasmid DNA to increase the transgene expression in HepG2 cells. In addition, there was no significant enhancement in gene transfer detected for other human cell lines tested, including THLE-3, AD293, and MCF-7 cells. Therefore, we demonstrate that HBP provides targeted gene delivery to HCC by cationic liposomes.