• International Journal of Industrial Entomology and Biomaterials
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• v.34 no.1
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• pp.11-15
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• 2017

We constructed the fibroin H-chain expression system to produce enhanced cyan fluorescent proteins (ECFP) in transgenic silkworm cocoon. Fluorescent cocoon could be made by fusing ECFP cDNA to the heavy chain gene and injecting it into a silkworm. The ECFP fusion protein, each with N- and C-terminal sequences of the fibroin H-chain, was designed to be secreted into the lumen of the posterior silk glands. The expression of the ECFP/H-chain fusion gene was regulated by the fibroin H-chain promoter. The use of the 3xP3-driven EGFP cDNA as a marker allowed us to rapidly distinguish transgenic silkworms. The EGFP fluorescence became visible in the ocelli and in the central and peripheral nervous system on the seventh day of embryonic development. A mixture of the donor and helper vector was micro-injected into 1,020 Kumokjam, bivoltin silkworm eggs. We obtained 6 broods. The cocoon was displayed strong blue fluorescence, proving that the fusion protein was present in the cocoon. Accordingly, we suggest that the ECFP fluorescence silk will enable the production of novel biomaterial based on the transgenic silk.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.321-329
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• 2005

Ornithine decarboxylase (ODC) antizyme is a key regulatory protein in the control of cellular polyamines. We have isolated two distinct ODC antizyme cDNA clones (AZS and AZL) from a flounder (Paralichthys olivaceus) brain cDNA library. Their sequences revealed that both clones required translational frameshifting for expression. Taking + 1 frameshifting into account, AZS and AZL products were 221 and 218 amino acid residues long, respectively, and shared $83.3\%$ amino acid sequence identity. Comparison of the structure and nucleotide sequence of the antizyme genes showed that the genes were highly conserved in flounder, zebrafish, mouse, and human. A phylogenetic tree was constructed, based on the antizyme amino acid sequences from various species. The presence of the two types of antizyme mRNA species in brain, kidney, liver, and embryo was confirmed by using the reverse transcription­polymerase chain reaction (RT-PCR) and Northern blot analysis. Recombinant proteins of flounder ODC antizymes, containing His-Nus-S tag at the amino-terminus, were overexpressed as His-AZL and His-AZS fusion proteins in Escherichia coli BL21 (DE3) pLys by using the pET­44a(+) expression vector.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.143.3-144
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• 2003

A Korean isolate of Pepper mild mottle virus (PMMoV-Kr) was isolated from a diseased pepper crop in Chunchon, Korea. The isolate was biologically purified on Nicoticaa tabacum cv. Xanthi-nc by successive single local transfer steps, and propagated on N. tabacum cv. Samsun. PMMoV-Kr could systemically infect on N. glauca, N. benthmiana, N. occidentalis and Lycopersicon esculentum, which is typical of known isolates of PMMoV. PMMoV-Kr belongs to the pathotype P1,2 based on pepper-tobamoviral indicator experiments; Capsicn chinone harboring L3 gene revealed resistant (necrotic local lesion on inoculated leaf, HR) whereas L+, L1 and L2 pepper plants expressed susceptible reactions of mosaic systemic symptoms for the isolate. To confirm the pathology and delineate symptom determinant of the isolate, full-length cDNAs of PMMoV-Kr were amplified by RT-PCR with a primer set corresponding to the 5'- and 3'-ends of PMMoV. The RT-PCR molecules amplified from genome RNA of the isolate was cloned into the pUC18 vector. Full-length cDNA clones constructed under the control of the T7 RNA promoter could be successfully transcribed to produce in vitro transcript RNA. Infectivity of the capped transcripts and its progeny virus was verified by Western blot and RT-PCR analyses.

• KSBB Journal
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• v.20 no.3
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• pp.220-227
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• 2005

Doxorubicin is an anthracycline-family polyketide compound with a very potent anti-cancer activity, typically produced by Streptomyces peucetius. To understand the potential target biosynthetic genes critical for the doxorubicin everproduction, a doxorubicin-specific DNA microarray chip was fabricated and applied to reveal the growth-phase-dependent expression profiles of biosynthetic genes from two doxorubicin-overproducing strains along with the wild-type strain. Two doxorubicin-overproducing 5. peucetius strains were generated via over-expression of a dnrl (a doxorubicin-specific positive regulatory gene) and a doxA (a gene involved in the conversion from daunorubicin to doxorubicin) using a streptomycetes high expression vector containing a strong ermE promoter. Each doxorubicin-overproducing strain was quantitatively compared with the wild-type doxorubicin producer based on the growth-phase-dependent doxorubicin productivity as well as doxorubicin biosynthetic gene expression profiles. The doxorubicin-specific DNA microarray chip data revealed the early-and-steady expressions of the doxorubicin-specific regulatory gene (dnrl), the doxorubicin resistance genes (drrA, drrB, drrC), and the doxorubicin deoxysugar biosynthetic gene (dnmL) are critical for the doxorubicin overproduction in S. peucetius. These results provide that the relationship between the growth-phase-dependent doxorubicin productivity and the doxorubicin biosynthetic gene expression profiles should lead us a rational design of molecular genetic strain improvement strategy.

• The Korea Journal of Herbology
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• v.24 no.3
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• pp.59-68
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• 2009

Objectives : Bupleuri Radix (Siho) is prescribed as the root of different Bupleurum species on the pharmarcopoeia in Korea and China. Moreover, other species and varieties of the genus Bupleurum have been also distributed on the herbal market as Bupleuri Radix. However, due to the morphological similarity and frequent occurrence of intermediate forms, the correct identification of this radix is very difficult. To develop a reliable method for correct identification and improving the quality standards of official Bupleuri Radix, we analyzed sequences of the ribosomal RNA gene and internal transcribed spacer (rDNA-ITS) region. Methods : PCR amplification of rDNA-ITS region was performed using ITS1 and ITS4 primer from 6 Bupleurum species and 1 variety, B. falcatum L. (Siho), an improved breed of B. falcatum L. (Samdo-Siho), B. chinense DC. (Buk-Siho), B. scorzonerifolium Willd. (Nam-Siho), B. longiadiatum Turcz. (Gae-Siho), B. euphorbiodes Nakai (Deungdae-Siho) and B. latissimum Nakai (Seom-Siho), and nucleotide sequence was determined after sub-cloning into the pGEM-Teasy vector. Authentic marker nucleotides were estimated by the analysis of ClastalW using entire rDNA-ITS sequence of three samples per species. Results : In comparative analysis of the rDNA-ITS sequences, we found specific nucleotides to distinguish Korean (B. falcatum L. and its variety) and Chinese official species (B. chinense DC. and B. scorzonerifolium Willd.) from others at positions 411 and 447, and positions 89, 101, 415 and 599, respectively. Futhermore, we also found nucleotide indels (insertion and/or deletion) and substitutions to identify each of different Bupleurum species, 2 positions for B. falcatum L. and its variety, 6 positions for B. chinense DC., 49 positions for B. scorzonerifolium Willd., 8 positions for B. euphorbioides Nakai, 7 positions for B. longiradiatum Nakai and 9 positions for B. latissimum Nakai. These sequence differences at corresponding positions are avaliable nucleotide markers to determine the botanical origins of Bupleuri Radix. Moreover, we confirmed the phylogenetic relationship of B. latissimum Nakai, a Korean endemic speices, among Bupleurum species based on the rDNA-ITS sequence. Conclusions : These marker nucleotides would be useful to identify the official herbal medicines by the providing of definitive information that can identify each plant species and distinguish it from unauthentic adulterant Bupleurum species.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.360-364
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• 2006

Fibrin clots of blood vessels are one of the serious factor caused cardiovascular disease. The development of a antithrombotic and thrombolysis solvent is necessary to prevent and treat these diseases. It has been reported that a strong fibrin-specific fibrinolytic enzyme was produced from a Korean fermented soybean paste similar to Japanese miso. We have been screened the known or novel fibrinolytic enzymes by activity-based and sequence-based screening from soil DNA metagenome library containing all kinds of environmental genomic DNA. The activity-based screening was determined the protease activity on 0.5% skim milk. For sequence-based screening, we designed a set of primer expanding gene sequence of fibrinolytic enzyme, performed PCR and selected clones showing the expected size of amplicons from metagenome library. Transformation of the gene encoding fibrinolytic enzyme was carried out with commercial vectors and their transformants were selected. Finally, we found 15 positive clones from metagenome library. Then each of sequences were analyzed and identified as similar or known the clones of nattokinase. We are going to perform full sequence of each clones, ligate with expression vector, transform into competent cells and then determine activity of expressed enzymes.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.277-283
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• 2009

One of the limitations to conducting maize Agrobacterium-mediated transformation using explants of immature zygotic embryos routinely is the availability of the explants. To produce immature embryos routinely and continuously requires a well-equipped greenhouse and laborious artificial pollination. To overcome this limitation, an Agrobacterium-mediated transformation system using explants of type II embryogenic calli was developed. Once the type II embryogenic calli are produced, they can be subcultured and/or proliferated conveniently. The objectives of this study were to demonstrate a stable Agrobacterium-mediated transformation of maize using explants of type II embryonic calli and to evaluate the efficiency of the protocol in order to develop herbicide-resistant maize. The type II embryogenic calli were inoculated with Agrobacterium tumefaciens strain C58C1 carrying binary vector pTF102, and then were subsequently cultured on the following media: co-cultivation medium for 1 day, delay medium for 7 days, selection medium for $4{\times}14$ days, regeneration medium, and finally on germination medium. The T-DNA of the vector carried two cassettes (Ubi promoter-EPSPs ORF-nos and 35S promoter-bar ORF-nos). The EPSPs conferred resistance to glyphosate and bar conferred resistance to phosphinothricin. The confirmation of stable transformation and the efficiency of transformation was based on the resistance to phosphinothricin indicated by the growth of putative transgenic calli on selection medium amended with $4mg\;1^{-1}$ phosphinothricin, northern blot analysis of bar gene, and leaf painting assay for detection of bar gene-based herbicide resistance. Northern blot analysis and leaf painting assay confirmed the expression of bar transgenes in the $R_1$ generation. The average transformation efficiency was 0.60%. Based on northern blot analysis and leaf painting assay, line 31 was selected as an elite line of maize resistant to herbicide.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.27-32
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• 2004

Using MLV (murine leukemia virus)-based retrovirus vectors encapsidated with VSV-G (vesicular stomatitis virus G glycoprotein), we tried to make transgenic chickens carrying the transferred genes in their chromosomes. Twenty one days after virus injection beneath the blastoderms of unincubated chicken embryos (stage Ⅹ, at laying), DNA isolated from the hatched chicks were analyzed by PCR with two sets of primers specific for EGFP (enhanced green fluorescence protein) gene or $Neo^R$ (E. coli neomycin resistant) gene. Among sixty-seven embryos injected with retrovirus, four of them were identified to carry the EGFP genes in their genomes. Remarkably, one transgenic chick showed presence of the retrovirus vector sequences in all organs differentiated from one of endoderm, mesoderm, and ectoderm. Expression of EGFP gene was not detected, however, the stable germ line transmission of transgene was verified in spermatozoa from the founder chicken and 50% of $F_1$ progenies.

• Reproductive and Developmental Biology
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• v.35 no.4
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• pp.449-455
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• 2011

Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by etopic expression of transcription factors. iPS cells are indistinguishable from ES cells in terms of morphology and stem cell marker expression. Moreover, mouse iPS cells give rise to chimeric mice that are competent for germline transmission. However, mice derived from iPS cells often develop tumors. Furthermore, the low efficiency of iPS cell generation is a big disadvantage for mechanistic studies. Nonviral plasmid.based vectors are free of many of the drawbacks that constrain viral vectors. The histone deacetylase inhibitor valproic acid (VPA) has been shown to improve the efficiency of mouse and human iPS cell generation, and vitamin C (Vc) accelerates gene expression changes and establishment of the fully reprogrammed state. The MEK inhibitor PD0325901 (Stemgent) has been shown to increase the efficiency of the reprogramming of human primary fibroblasts into iPS cells. In this report, we described the generation of mouse iPS cells devoid of exogenous DNA by the simple transient transfection of a nonviral vector carrying 2A-peptide-linked reprogramming factors. We used VPA, Vc, and the MEK inhibitor PD0325901 to increase the reprogramming efficiency. The reprogrammed somatic cells expressed pluripotency markers and formed EBs.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.335-341
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• 2017

The complexity of the bacterial recombination system is a barrier for the construction of bacterial mutants for the further functional investigation of specific genes. Several protocols have been developed to inactivate genes from the genus Pseudomonas. Those protocols are complicated and time-consuming and mostly do not enable easy construction of multiple knock-ins/outs. The current study describes a single and double crossover-recombination system using an optimized vector-free allele-exchange protocol for gene disruption and gene replacement in a single species of the family Pseudomonadaceae. The protocol is based on self-ligation (circularization) for the DNA cassette which has been obtained by overlapping polymerase chain reaction (Fusion-PCR), and carries an antibiotic resistance cassette flanked by homologous internal regions of the target locus. To establish the reproducibility of the approach, three different chromosomal genes (ncRNA31, rpoN, rpoS) were knocked-out from the root-associative bacterium Pseudomonas stutzeri A1501. The results showed that the P. stutzeri A1501 mutants, which are free of any plasmid backbone, could be obtained via a single or double crossover recombination. In order to optimize this protocol, three key factors that were found to have great effect on the efficiency of the homologous recombination were further investigated. Moreover, the modified protocol does not require further cloning steps, and it enables the construction of multiple gene knock-in/out mutants sequentially. This work provides a simple and rapid mutagenesis strategy for genome editing in P. stutzeri, which may also be applicable for other gram-negative bacteria.