• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.117-132
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• 1987

Plants are inherited spatial and temporal coordination systems in their growth and differentiation processes which are precisely governed by the two interlocked control systems; autogenous and environmental. Looking into the overall course of plant development from molecular to organismal level, it can be comparable to a concerto for plant hormones, environmental stimuli and plant genomic orchestra conducted by an unidentified virtuoso. Some of the recent significant attempts to puzzle out the mystery of the life processes of plant development are briefly reviewed. The revolutionary advances in understanding the mystic processes are contemporarily achieved by the application of various molecular techniques. The characterization of plant genomes is now attained through recombinant DNA approaches, and the sensitive detection of specific gene products during the plant development is perimitted by the immunochemical procedures. However, along with the recognition of underlying molecular events such as developmental changes in gene expression and hormone-receptor interrelation associated with tissue sensitivity to hormones, more emphasis should be placed upon the physiological approaches of organismal level for the understanding the correlative systems of the developmental processes of plants as intact eukaryotic organisms.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.241-260
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• 1987

The regulatory mechanisms of gene expression in higher plant were not ascertained in detail because the genome size is very large and complex. However, the above-mentioned study is remarkably progressed in parallel with development of DNA recombinant technology and plant vector system. Some research results connected with the mechanisms could be summarized as follows. 1. Many plant genes including chloroplast genes are cloned. 2. The structures of some regulatory regions of gene expression are determined, and it is confirmed that new regulatory units are made by transposable elements. 3. Plant gene expression is regulated not only at transcriptional level but also at translational level. 4. The factors that regulate plant gene expression could be divided as two categorys. One is endogenous elements including the structural change of chromatin during development stage and tissue differentiation. The other is environmental stimulations such as air, water, heat, salts and light. However, some sufficient research-aid fund is essential in order to study the regulatory mechanisms of gene expression more systematically.

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.55-55
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• 1999

Imperatoxin A (IpTx$_{a}$), a 3.7 kDa peptide from the African scorpion Pandinus imperator, has been known as an agonist of skeletal ryanodine receptor (RyR). In order to study the structure and function of the toxins on RyR, the IpTx$_{a}$ cDNA was PCR-amplified using 3 pairs of primers and the toxin was expressed in E. coli expression system.(omitted)ted)

• Journal of Pharmaceutical Investigation
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• v.23 no.4
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• pp.187-206
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• 1993

Since the advent of recombinant DNA technology coupled with other biotechnology a variety of therapeutically effective proteins and peptides have been extensively invesitigated and many of them are now on clinical trial. They, however, suffer from some problems such as immunogenicity, antigenicity, instability and short half-life in circulation due to their proteinous natures. These drawbacks can be overcome successfully by conjugating proteins and peptides with hydrophilic polymers such as polyethylene glycol (PEG), albumin or dextran. The resulting soluble conjugates showed reduced antigenicity and immunogenicity, increased circulatory half-life, enhanced stability against proteolytic degradation. Comparing with the unmodified proteins and peptides, the therapeutic potential of conjugates is greatly enhanced. Clinical applications of these conjugates have shown promising results for the future use.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.77-84
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• 2009

Using recombinant DNA technology, the vector system containing minimal fragment of a bacterial hemoglobin gene (vgb) was constructed. When this vector was inserted into Escherichia coli, the growth of the host was significantly improved in both viable cell counts and absorbance measurement, compared to that of the wild type strain. In addition, by minimizing the size of bacterial hemoglobin in the vector, the ability of vgb in growth improvement was augmented, due to the reduction of metabolic burden from the maintenance and replication of the plasmid. By using this system, it is expected that the growth of microorganisms can be improved even in the hypoxic condition.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.53-58
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• 2000

A cDNA encoding the luciferase of firefly Luciola lateralis was cloned downstream from the polyhedrin gene promoter of Bombyx mori nucleopolyhedrovirus and expressed in B. mori cells (BmN-4). The coding soquence for luciferase was inserted into pBmKSK2 rectors) which was reconstructed from the polyhedrin-based transfer vector pBmKSKl by modifying cloning sites. Recombinant virus, BmK2-LUCDF, containing the luciferase gene was selected and purified in BmN-4 cells. The emission of luminescence by luciferase was only detected in BmK2-LUCDF-infected cell extracts. This result indicates that the cloned new luciferase gene of firefly L. lateralis can be expressed efficiently in baculovirus expression system and used as a useful reporter gene.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.201-207
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• 2018

Porphyromonas gingivalis is among the major etiological pathogens of chronic periodontitis. The virulence mechanisms of P. gingivalis is yet to be identified as its activity is largely unknown in actual disease process. The purpose of this study is to identify antigens of P. gingivalis expressed only in patients with chronic periodontitis using a unique immunoscreening technique. Change Mediated Antigen Technology (CMAT), an antibody-based screening technique, was used to identify virulence-associated proteins of P. gingivalis that are expressed only during infection stage in patients having chronic periodontitis. Out of 13,000 recombinant clones screened, 22 tested positive for reproducible reactivity with rabbit hyperimmune anti-sera prepared against dental plaque samples acquired from periodontitis patients. The DNA sequences of these 18 genes were determined. CMAT-identified protein antigens of P. gingivalis included proteins involved in energy metabolism and biosynthesis, heme and iron binding, drug resistance, specific enzyme activities, and unknown functions. Further analysis of these genes could result in a novel insight into the virulence mechanisms of P. gingivalis.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.148.1-148
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• 2003

Natural virus infection of cultivated Daphe odora plants showing chlorosis and stunting was observed and their causal agent was investigated. An isolate of isometic virus was purified from infected leaf tissues, and it could infect systemic severe mosaic on Chenopodium quinoa and C. amaranticolor. cDNA library was generated from partially purified viral RNAs and oligo dT primer-pSPORTl system, and recombinant clones were selected and their inserts were sequenced randomly. Nucleotide sequences of the virus were analyzed by BLAST, and it was closely related to members of subgroup B in the genus Nepovirus. The sequence analysis suggest that the virus was identified as an isolate of Cycas necrotic stunt virus (CNSV) because it was 89.7 ％ and 94.7 ％ identical to known CNSV for the CP and 3' noncoding region, respecitively. RT-PCR was performed to screen disease incidence of CNSV in Daphe plants, and five out of 10 plants (50 ％) were infected by CNSV This is the first sequence information of CNSV from Daphe plants.

• Molecules and Cells
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• v.20 no.1
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• pp.142-150
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• 2005

Members of the multifunctional Cyp family have been isolated from a wide range of organisms. However, few functional studies have been performed on the role of these proteins as chaperones in red alga. For studying the function of cDNA GjCyp-1 isolated from the red alga (Griffithsia japonica), we expressed and purified a recombinant GjCyp-1 containing a hexahistidine tag at the amino-terminus in Escherichia coli. An expressed fusion protein, $H_6GjCyp-1$ maintained the stability of E. coli proteins up to $50^{\circ}C$. For a functional bioassay for recombinant $H_6GjCyp-1$, the viability of E. coli cells overexpressing $H_6GjCyp-1$ was compared with that of cells not expressing $H_6GjCyp-1$ at $50^{\circ}C$. After high temperature treatment for 1 h, E. coli overexpressing $H_6GjCyp-1$ survived about three times longer than E. coli lacking $H_6GjCyp-1$. Measurement of the light scattering of luciferase (luc) showed that GjCyp-1 prevents the aggregation of luc during mild heat stress and that the thermoprotective activity of GjCyp-1 is blocked by cyclosporin A (CsA), an inhibitor of Cyps. Furthermore, the Cyp-CsA complex inhibited the growth of E. coli under normal conditions. The results of the GjCyp-1 bioassays as well as in vitro studies strongly suggest that Cyp confers thermotolerance to E. coli.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.151-162
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• 1996

Pseudorabies is caused by Pseudorabies virus (PRV: Aujeszky's disease virus) of Herpesviridae that is characterized by 100 to 150nm in size with a linear double-stranded DNA molecule with of approximately $90{\times}10^6Da$. This disease affects most of domestic animals such as swine, cattle, dog, sheep, cat, chicken, etc. causing high mortality and economic losses. In swine, young piglets show high mortality and pregnant sows, reproductive failures. However the adult swine reveals no clinical signs in general. But they become a carrier state and play an important role for propagation of the disease. In this study, the nucleotide sequence of major casid protein gene of PRV, Yangsan strain isolated from the diseased swine in Korea was analyzed, and the recombinant MCP was produced by expression of the MCP gene in Sf-9 cell using baculovirus transfer vector system. As result, in BamHI digestion, MCP gene locus of PRV YS strain showed different from that of Indiana S strain. The patterns of enzyme mapping were also found to be unidentical each other. The sequence of the MCP gene partially analyzed showed 98.09% identity to Indiana S strain. The expression of MCP in Sf-9 cell cotransfected by pVLMCP-44 baculovirus expression vector was characterized by Southern blot hybridization, immunofluoresent and immunocytochemical tests, SDS-PAGE and Western blotting. The rMCP with M.W. 142kDa was most effectively expressed in Sf-9 cells at the 3-4th days post inoculation of the recombinant baculovirus by 2 moi.