• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.143-148
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• 2015

In some pathogenic bacteria, there are RNA thermometers, which regulate the production of virulence associated factors or heat shock proteins depending on temperature changes. Like a riboswitches, RNA thermometers are located in the 5'-untranslated region and involved translational gene regulatory mechanism. RNA thermometers block the ribosome-binding site and start codon area under the $37^{\circ}C$ within their secondary structure. After bacterial infection, increased the temperature in the host causes conformations changes of RNA, and the ribosome-binding site is exposed for translational initiation. Because structural differences between open and closed forms of RNA thermometers are mainly mediated by base pairing changes, NMR spectroscopy is a very useful method to study these thermodynamically changing RNA structure. In this review, we briefly provide a fundamental function of RNA thermometers, and also suggest a proper NMR experiments for studying RNA thermometers.

• Applied Biological Chemistry
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• v.15 no.3
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• pp.187-192
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• 1972

The qualitative and quantitative changes in RNA in terms of RNase activity of rice plants subjected to the chilling temperature were studied. The total RNA level increased at the early stage and thereafter decreased continuously while the progress of the chilling injury. The change of total RNA was mainly dependent upon the change of ribosomal RNA with soluble RNA less changed. Parallelism between total RNA level and RNase activity was observed at the early stage of chilling injury, while the inverse relationship of RNA RNase was seen in the later stage. Our observations indicate that synthetic function of RNase may be more closely related to ribosomal RNA than soluble RNA.

• Journal of Aquaculture
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• v.18 no.1
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• pp.7-12
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• 2005

This study was conducted to investigate antioxidant enzyme activity (catalase and superoxide dismutase) and Heat Shock Protein 70 (HSP70) mRNA variation in hepatopancreas of abalone (Haliotis discus hannai) cultured under several acute water temperatures. Abalones were cultured at 10, 15, 20, 25 and $30^{\circ}C$, for 0, 6, 12, 24 and 48 hours, respectively. The HSP70 mRNA expression in hepatopancreas was more increased at $30^{\circ}C$ compared to those at 10. 15, 20 (control) and $25^{\circ}C$. The superoxide dismutase (SOD) activity was increased in hepato-pancreas at all water temperature conditions compared to the control ($20^{\circ}C$). The SOD activity at high water temperature (25 and $30^{\circ}C$) tended to be increased after 12 hours, and was increased immediately after exposure to low water temperature (10 and $15^{\circ}C$). and then was recovered to starting level after the increase. Also, catalase (CAT) activity in hepatopancreas was increased in all the groups except for at $10^{\circ}C$ than the control ($20^{\circ}C$). Survival rate of abalone was $100\%$ at 10, 15, 20 and $25^{\circ}C$, but $92\%$ at $30^{\circ}C$. Thus, according to our study, when abalone is appeared at $20^{\circ}C$, defense mechanism against stress at low water temperature can be accelerated to be stabilized at about $5^{\circ}C$. In the case of exposure of abalone to high water temperature, antioxidant enzyme and HSP70 expression were increased due to elevated physiological stimulation factor, such as temperature.

• Korean Journal Plant Pathology
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• v.2 no.2
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• pp.121-128
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• 1986

The biochemical properties of ribonucleic acid (RNA) and coat protein of the mild tobacco mosaic virus (TMV) mutant, Tw 333 are described. The molecular weight of the RNA calculated from polyacrylamide gel electrophoresis was $2.03\times10^6$ daltons. The molar ratio of the bases of the RNA was 25.4 guanine, 29.2 adenine, 17.5 cytosine and 27.9 uracil in moles. The hyperchromicity on Tw 333-RNA by thermal denaturation was $25.1\%$, indicating Tm value of $47^{\circ}C$. The virus coat protein migrated as a single component in SDS-polyacrylamide gel electrophoresis and had a molecular weight of 17,500 daltons. A total of 158 amino acid residues are present in the protein. Separation of the tryptic peptides by electrophoresis and chromatography yielded ninhydrin-positive compounds. The biochemical properties of RNA and coat protein of the mild mutant we very similar to those of wild type of TMV-OM strain, but some difference between the strains were observe in the base composition, hyperchromicity, amino acid composition and tryptic peptide map.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.535-540
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• 1990

Bacitlus sphaericus ts-Dl290 was characterized comparatively with the wild type strain 1593 by themeasurements of the biosynthesis of total DNA, RNA and protein on the temperature-shift culturesat permissive temperature of $30^{\circ}C$ and at nonpermissive temperature of $42^{\circ}C$. The growth patterns of the wild type strain and ts-Dl290 were similar at $30^{\circ}C$, but at 4Z C the mutant almost did not grow (temperature-sensitivity). When the growth temperatures of both stains were shifted-up from $30^{\circ}C$ to $42^{\circ}C$ after a 4 hour culture, their growths were normal, but when shifted-down from $42^{\circ}C$ to $30^{\circ}C$ after a 4 h culture, the mutant did not grow. When shifted up from $30^{\circ}C$ to $42^{\circ}C$ after a 4 hculture, the DNA syntheses of the two strains were at a normal rate for 1 h, but after 1 h the biosynthesesdecreased. The rate of DNA synthesis of the wild type strain at the nonpermissive temperature was about 93%, and that of the mutant was about 50% of the ratio of the wild type strain, and the RNA synthesis of the wild type strain was maintained for 3 h, and that of the mutant for 2 h. Thereafter the RNA synthesis decreased, and the synthesis of proteins in the both strains were similarlykept high for 8 h. The reversibility of the DNA synthesis of the mutant at $42^{\circ}C$ was lessened whenthe culture times were increased.re times were increased.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.241-248
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• 2017

BACKGROUND: RNA interference (RNAi) eliminates or decreases gene expression by disrupting the target mRNA or by interfering with translation. Recently, RNAi technique was applied to generate new crop traits which provide protection against pests. To establish the environmental risk assessment protocol of RNAi LMO in lab scale, we developed dsRNA expression system using E. coli and tested acute oral toxicity assay to honey. METHOD AND RESULTS: The dsRNA expression vector, L4440, was chosen and cloned 240 bp of Snf7 and GFP gene fragment. To develop the maximum dsRNA induction condition in E. coli, we tested induction time, temperature and IPTG concentration in media. To estimate the risk assessment of dsRNA to honey bee, it has been selected and cultured with dsRNA supplement for 48 hours according to OECD guideline. As a result, the optimum condition of dsRNA induction was $37^{\circ}C$, 4 hours and 0.4 mM IPTG concentration and the difference between Snf7 and GFP dsRNA molecules from E. coli was not significant in survival and behavior to honey bee. Furthermore, blast search results indicated that effective match of predicted dsRNA fragments were not existed in honey bee genome. CONCLUSION: In this study, we developed and tested the acute oral toxicity of dsRNA using E. coli expression system to honey bee.

• Microbiology and Biotechnology Letters
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• v.8 no.1
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• pp.9-18
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• 1980

During an extensive screening tests of yeasts for their RNA formation, it was found that Cryptococcus laurentii had especially high RNA content and high dry cell weight, when hydrolyzate of sliced and dried sweet potatoes was used as a carbon source. Growth conditions of this strain were examined, and the most desirable results were obtained at 48 hours of cultivation on a reciprocal shaker at 3$0^{\circ}C$ with initial pH 6.0. Under the above conditions, the RNA content and yield of dry cells were investigated using various media compositions. Ammonium sulfate 0.40%, peptone 0.6 ％, and yeast extract 0.4% were appeared to be favorable as a nitrogen sources. The optimum concentrations of K $H_2$P $O_4$, M $n^{++}$, C $O^{++}$ were 0.05 ％, 0.1 ％, and 0.001 ％, respectively. Ca-pantothenate, 400$\mu\textrm{g}$/$m\ell$, showed relatively favorable effects as a growth factor. The maximum RNA content obtained in this study was 16.8 ％ of the total dry cell weight.t.t.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.465-474
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• 2005

A two-step broad-range PCR method detecting gram-negative bacteria at the level as low as 2 CFU was developed by using primers of GNFI and GNRI and then semi-nested primer of GNF2 and GNRI. The nucleotide sequences of the primers were determined based on l6S rRNA gene. The DNA fragments of 1173 bp and 169 bp were amplified in one-step PCRs with primer sets of GNFI-GNRI and GNF2-GNRl, respectively, using template DNA from seven strains of gram-negative bacteria including Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas spp., and Acinetobacter baumaii but not from Achromobacter lyticus, Alca/igens faecalis, and five strains of gram-positive bacteria. DNA fragments of 180 bp were amplified from LTLT-pasteurized milk and UHf-pasteurized milk in the two-step PCR. The DNA fragments were amplified from LTLT-pasteurized milk which was added with Pseudomonas j/uorescens and subsequently heated at 65 $^{\circ}C$, 80 $^{\circ}C$, and 100 $^{\circ}C$ for 30 min but they were not amplified from the milk autoclaved at 121$^{\circ}C$ for 15 min. It was suggested in PCR that Pseudomonas fluorescens heated at 65 $^{\circ}C$ for 30 min in milk was more sensitive to DNase treatment than viable bacteria.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.450-458
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• 2015

The heat shock proteins (Hsps), one of the most highly conserved groups of proteins, play crucial roles in protecting cells against environmental stressors, such as temperature, salinity, heavy metals and pathogenic bacteria. The glutathione S-transferases (GST) have important role in detoxification of oxidative damage, environmental chemicals and environmental stress. The purpose of this study is to investigate the gene expression of Hsp70 and GST on change of temperature and salinity in Mytilus coruscus. The M. coruscus was cultured in incubator of separate temperature and salinity (8, 20, $30^{\circ}C{\times}20$‰, 25‰, 30‰) for 28 days. Ten individuals in each group were selected after each 14 and 28 days exposure. Results that the expression of Hsp70 mRNA was no significant changed in M. coruscus exposed to temperature ($8^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$) and salinity (20‰, 25‰, 30‰) for 14 days. Whereas the expression of Hsp70 mRNA was increased in exposure to temperature $30^{\circ}C$ and salinity (20‰, 25‰, 30‰) for 28 days. The expression of GST mRNA was increased in exposure to temperature $30^{\circ}C$, salinity (25‰, 30‰) for 14 days and temperature ($8^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$), salinity (20‰, 25‰, 30‰) for 28 days. These results suggest that Hsp70 and GST were played roles in biomarker gene on the thermal and salinity stress.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.222-226
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• 2007

Proteases are degradative enzymes which hydrolyze a peptide bond between amino acids and they are abundantly applied to commercial field. In order to screen new source of pretense, bacteria secreting extracellular pretense were isolated by enrichment culture from deep sea water samples of East Sea, Korea. A bacterium, named as HJ19, showed the best growth and the largest clear zone in plates supplemented skim milk at $30^{\circ}C$. The partial DNA sequence analysis of the 16S rRNA gene, phenotypic tests and morphology identified that this strain was In genus Micrococcus. The strain HJ19 could not grow at $10^{\circ}C$ but it started growth and showed pretense activity at $20^{\circ}C$. The optimal growth was at $37^{\circ}C$ and the maximal protease activity at $30^{\circ}C$ was about 480unit/ml.