• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.396-402
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• 2012

The chemical composition, anti-porcine epidemic diarrhea virus (PEDV) activity and antimicrobial activity of Artemisia dubia essential oil were evaluated in this study. Fifty eight compounds from A. dubia essential oil were identified through analysis by gas chromatography-mass spectrometry (GC-MS). The major constituents of the oil were camphor (17.18 %), germacrene-D (15.70%), trans (${\beta}-$) racaryophyllene (6.79%), ene thujones (6.57%), 1, 8-cineole (5.94%) and camphene (5.08%). The essential oil was evaluated for antiviral activity against PEDV in Vero cells using a cytopathic effect (CPE) reduction method. The oils actively inhibited PEDV replication with a 50% inhibitory concentration ($IC_{50}$) of 43.7 ${\mu}^3/mL$. The 50% cytotoxicity concentration ($CC_{50}$) of the oils was over 100 ${\mu}/mL$ and the derived therapeutic index was >2.3. Similar analysis of the ribavirin revealed that they have a relatively weaker efficacy when compared to the oils. The antimicrobial activity of the essential oil against 5 microorganisms was evaluated by the disc diffusion method. The essential oil exhibited antimicrobial activity against 5 tested microorganisms with a clear zone of 8-22 mm. Among the tested microorganisms, Streptococcus pyogenes was the most sensitive and Candida albicans the least. Therefore, in can be concluded that essential oils of A. dubia may have interesting applications for microbial control or the control of PEDV-derived diseases.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.287-292
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• 2009

The nucleocapsid (N) protein of porcine reproductive and respiratory syndrome virus (PRRSV) is a basic multifunctional protein which has been reported to be a serine phosphoprotein with yet-identified functions. As a first step towards understanding the general role of N protein phosphorylation during virus replication, the non-phosphorylated mutant N gene was constructed by mutating all serine residues to alanine. This recombinant N protein was identified to be unphosphorylated, confirming that serine residues truly function as core amino acids responsible for N protein phosphorylation. The PRRSV N protein has been shown to possess the biological features of nuclear localization and N-N homodimerization which individually play critical roles in virus infection. In the present study, therefore, it was attempted to investigate whether these two properties of the N protein are modulated by its phosphorylation status. However, experimental results showed that the non-phosphorylated N protein was still present in the nucleus and nucleolus, and was able to associate with itself by non-covalent interactions. Taken together, the data suggest phosphorylation-independent regulation of N protein nuclear transport or oligomerization, thereby implying the potential involvement of phosphorylation in regulating the activities of the N protein at other levels including RNA-binding capacity.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.23-33
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• 1998

The entire sequence of a 4,214,810 bp genome of the Bacillus subtilis 168 has been determined by an international project, and the completion has been announced on July 19, 1997. For the sequencing project an international consortium was established and 25 European, 7 Japanese laboratories, 2 biotechnology companies, and our laboratory participated in the project. Within this framework we determined the complete nucleotide sequence of a 53,289 bp fragment upstream of the odhA gene (181 $^{\circ}$) of the B. subtilis 168 chromosome. On the basis of the published DNA sequences of the B. subtilis sspC and odhA genes, we obtained genomic fragments by plasmid rescue and long-range PCR. The sequenced fragment contains 56 putative open reading frames (designated yojA-yolI and 9 known genes (sspC, cge cluster, orfE5, orfRMl and odhA), in which we found many interesting features. In addition, the entire nucleotide sequence of a 53,289 bp region enabled us to revise the current genetic map of this region.

• Journal of Life Science
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• v.14 no.1
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• pp.131-140
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• 2004

T7 bacteriophage gp4 is the replicative DNA helicase that unwinds double-stranded DNA by utilizing dTTP hydrolysis energy. The quaternary structure of the active form of T7 helicase is a hexameric ring with a central channel. Single-stranded DNA passes through the central channel of the hexameric ring as the helicase translocates $5'\rightarrow3'$ along the single-stranded DNA. The DNA unwinding was measured by rapid kinetic methods and showed a lag before the single-stranded DNA started to accumulate exponentially. This behavior was analyzed by a kinetic stepping model for the unwinding process. The observed lag phase increased as predicted by the model with increasing double-stranded DNA length. Trap DNA added in the reaction had no effect on the amplitudes of double-stranded DNA unwound, indicating that the $\tau7$ helicase is a highly processive helicase. Global fitting of the kinetic data to the stepping model provided a kinetic step size of 10-11 bp/step with a rate of $3.7 s^{-1}$ per step. Both the mechanism of DNA unwinding and dTTP hydrolysis and the coupling between the two are unaffected by temperature from $4∼37^{\circ}C$. Thus, the kinetic stepping for dsDNA unwinding is an inherent property of tile replicative DNA helicase.

• Journal of Life Science
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• v.30 no.4
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• pp.402-409
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• 2020

Nervous necrosis virus (NNV) contains a bi-segmented viral genome, RNA1 (3.4 kb, RdRp), and RNA2 (1.4 kb, capsid protein) in a small particle (25 nm). Despite its extremely compact size, NNV has caused serious damage by infecting approximately 120 fish species worldwide since it was first reported in the late 1980s. In order to minimize the damage caused by NNV infection and develop effective vaccines, it is necessary to understand the intra cellular signaling system according to NNV infection. NNV infection induces cell cycle arrest at the G1 phase via the p53-dependent pathway to use the cellular system for its replication. Otherwise, host cells recognize NNV infection through the RIG-1-like receptor (RLR) signaling pathway to control the virus and infected cells, and then ISGs required for antiviral action are activated via the IFN signaling pathway. Moreover, apoptosis of infected cells is triggered by the unfolded protein response (UPR) through ER stress and mitochondria-mediated cell death. Cell signaling studies on the NNV infection mechanisms are still at an early stage and many pathways have yet to be identified. Understanding the various disease-specific cellular signaling systems associated with NNV infection is essential for rapid and accurate diagnosis and vaccine development.

• Journal of Life Science
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• v.29 no.12
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• pp.1329-1336
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• 2019

Subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) which self-renew and differentiate to neurons and glial cells during postnatal period and throughout adulthood. Since fate decision to either proliferation or differentiation has to respond to intracellular and extracellular conditions, many intrinsic and extrinsic factors are involved. Among them, mitochondria have been reported to participate in fate decision of NSCs. In our previous report, we showed that long-term treatment of a mitochondrial inhibitor rotenone greatly inhibited neurogenesis. In this study, we examined the effects of short-term treatment of rotenone on SVZ NSCs. We found that (1) even one-day treatment of rotenone significantly reduced neurogenesis and earlier time points seemed to be more sensitive to rotenone, (2) a number of Mash1+ transit amplifying cells was decreased by one-day treatment of rotenone, (3) short-term treatment of rotenone eliminated most of the differentiated Tuj1+ neurons and Olig2+ oligodendrocytes, while glial fibrillary acidic protein (GFAP)+ astrocytes were not affected, and (4) sulfiredoxin 1 (Srxn1) gene expression was increased after one-day treatment of rotenone, indicating activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. All these results confirm that functional mitochondria are necessary during differentiation to neurons or oligodendrocytes as well as maintenance of neurons after differentiation. Also, these data suggest that temporary exposure to mitochondrial inhibitor such as rotenone might have long-term effects on neurogenic potential of NSCs.

• Journal of Life Science
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• v.26 no.1
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• pp.8-16
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• 2016

Reactive oxygen species (ROS), at appropriate concentrations, mediate various normal cellular functions, including defense against pathogens, signal transduction, cellular growth, and gene expression. A recent study demonstrated that ROS and ROS-generating NADPH oxidase (Nox) are important in self-renewal and neuronal differentiation of subventricular zone (SVZ) neural stem cells in adult mouse brains. In this study, we found that endogenous ROS were detected in SVZ neural stem cells cultured from postnatal mouse brains. Nox4 was predominantly expressed in cultured cells, while the levels of the Nox1 and Nox2 transcripts were very low. In addition, the Nox4 gene was highly upregulated (by up to 10-fold) during neuronal differentiation. Immunocytochemical analysis detected the Nox4 protein mainly in neurons positive for the neuronal specific tubulin Tuj1. After differentiation, endogenous ROS were detected exclusively in neuron-like cells with processes. In addition, perturbation of the cellular redox state with N-acetyl cysteine, a ROS scavenger, during neuronal differentiation greatly inhibited neurogenesis. Lastly, knockdown of Nox4 using short hairpin RNA decreased neurogenesis. These findings suggest that Nox4 may be a major ROS-generating enzyme in postnatal SVZ neural stem cells, and Nox4-mediated ROS generation may be important in their neuronal differentiation.

• Journal of Science and Technology Studies
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• v.5 no.2 s.10
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• pp.97-127
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• 2005

While science museums, whose functions consist traditionally in collecting, preserving, researching, and displaying science-related objects, present scientific knowledge, figures, or tools in the historical context, science centers give more emphases on science education by exposing interactive exhibits to their visitors. However, neither objects-oriented exhibits nor hands-on technologies can provide museum visitors with the full insight into modem science in terms of its complicated relationships to politics, economy, culture, art, risk, and environment. This paper argues that for the 21st century we need to establish a new kind of science museum through the critical examination of its previous kinds - science museums and science centers. In the first part of this paper, the history of the first and second generations of science museums, including their recent trends in science centers, in the West will be elaborated. Secondly, the development of national science museums in Korea will be discussed specifically for the understanding of Korean science museums. The next part of this paper will seek for the possibilities of the third generation of science museums through three examples, which show interdisciplinary, contextual, and institutional approaches to change science museums or science centers. Fourthly, the social function of science museums as 'forum' will be discussed in relation to promoting public 'participation' of science as well as public 'understanding' of science. As a conclusion, some practical suggestions and conceptual guidelines will be proposed for the future Korean national science museum.

• Journal of Life Science
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• v.18 no.1
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• pp.75-83
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• 2008

This studies were designed to elucidate whether inhibitors of topoisomerase regulate function and activity of topoisomerase, and gene expression in HL-60 human leukemia cells. HL-60 cells were treated with 10-hydroxycamptothecin or doxorubicin, total RNA was isolated, and expressed genes were investigated with human oligonucleotide microarray containing 10K gene, respectively. Expression profiles of the human leukemia HL-60 cells treated with 10-hydroxycamptothecin (10-CIT) or doxorubicin associated with signal transduction,. cell adhesion, cell cycle, cell growth, cell proliferation, cell differentiation, transcription and immune response, especially genes related with transcription and cell growth. In HL-60 cells treated with 10-CPT, the expression of topoisomerase III${\alpha}$, III${\beta}$ and I gene from oligo chip microarray analysis were increased over, but the expression of topoisomerase II${\alpha}$ and II${\beta}$ gene were decreased over. In contrast, the expression of topoisomerase II${\alpha}$ and II${\beta}$ gene were increased over in HL-60 cells treated with doxorubicin, whereas the expression of topoisomerase III${\alpha}$ and III${\beta}$ mRNA remained no significant change. These results suggest that these data may be useful for novel therapeutic markers.

• Journal of Life Science
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• v.32 no.6
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• pp.463-467
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• 2022

As a result of applying the COG (Cluster of Orthologous Groups of Protein) algorithm to 1,309 species to confirm the conserved genes of prokaryotes, ribosomal protein S11 (COG0100) was identified. The numbers of conservative genes were 2, 5, 5, and 6 in 1,308, 1,307, 1,306, and 1,305 species, respectively. Twenty-nine genes were conserved in over 1,302 species, and they encoded 23 ribosomal proteins, 3 tRNA synthetases, 2 translation factors, and 1 RNA polymerase subunit. Most of them were related to protein production, suggesting the importance of protein expression in prokaryotes. The highest conservative COG was COG0048 (ribosomal protein S12) among the 29 COGs. The 29 conserved genes usually have one protein for each prokaryote. COG0090 (ribosomal protein L2) had not only the lowest conservation value but also the largest standard deviation of phylogenetic distance value. As COG0090 is not only a member of the ribosome, but also a regulator of replication and transcription, it could be inferred that prokaryotes have large variations in COG0090 to survive in various environments. This study could provide data necessary for basic science, tumor control, and development of antibacterial agents.