• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.109-116
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• 1987

As a process to establish an effective preventive measure of V. vulnificus septicemia, bactericidal effect of distilled water against V. vulnificus was studied. When about $2.0{\times}10^7\;CFU/ml$ of V. vulnificus was inoculated in distilled water, a dramatic decrease in the number of viable bacteria by 5 to $6LOG_{10}$ was observed in 5 minutes. Bactericidal kinetic curves could be divided into the first rapid killing phase until 1 minute and the later slow killing phase after then, showing the heterogeneity of the bacterial population inoculated. When V. vulnificus was inoculated in saline solutions having various salinities, significant decrease in the number of viable bacteria was noted only at salinities under 0.2%. The higher was the concentration of NaCl, the greater was the degree of protection against osmotic shock. When glucose, NaCl, $MgCl_2$, and $CaCl_2$ were diluted with deionized water to give same osmolarities and V. vulnificus was inoculated in each of them to compare the bactericidal curves plotted during the first 5 minutes after inoculation, the protection efficiencies were in the order of $MgCl_2>CaCl_2{\gg}NaCl{\gg}glucose$. Above results indicate that treatment(or thorough washing) of contaminated sea animals or other products with distilled water can be used as a preventive measure of V. vulnificus septicemia, and divalent cations can protect V. vulnifcus to osmotic shock with high efficiency.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.175-179
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• 1986

In order to develope a protoplast fusion of the genus Cellulomonas having high assimilibility of cellulose, the optimum conditions for the protoplast formation of Cellulomonas flavigena NCIB 12901 was investigated and observed by means of Scanning Electron Microscope. The results suggested that the susceptibility of the cell wall by lysozyme treatment on protoplast formation was considerably depend on the cultural periods of the cells. Cells of C. flavigena at mid exponential phase could more efficiently convert to protoplast cells than those at late exponential phase did. The rate of the protoplast formation was 95%, even though the rate was over 99.9% on counting by indirect method after osmotic shock treatment, when cells of the organism at mid exponential phase were treated with lysozyme (400$\mu\textrm{g}$/$m{\ell}$) for 6 hours and observed by SEM. In the evaluation of protoplast formation of the genus Cellulomonas, direct method of the observation under Scanning Electron Microscope was much more reliable than the counting method of protplasts after osmotic shock treatment. Because defferences between the number of spheroplast and protoplast were not able to be figured out on counting the number of protoplast after osmotic shock treatment.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1056-1069
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• 2015

Osmotic pressure is a critical factor for erythritol production with osmophilic yeast. Protein expression patterns of an erythritol-producing yeast, Yarrowia lipolytica, were analyzed to identify differentially-expressed proteins in response to osmotic pressure. In order to analyze intracellular protein levels quantitatively, two-dimensional gel electrophoresis was performed to separate and visualize the differential expression of the intracellular proteins extracted from Y. lipolytica cultured under low (3.17 osmol/kg) and high (4.21 osmol/kg) osmotic pressures. Proteomic analyses allowed identification of 54 differentially-expressed proteins among the proteins distributed in the range of pI 3-10 and 14.4-97.4 kDa molecular mass between the osmotic stress conditions. Remarkably, the main proteins were involved in the pathway of energy, metabolism, cell rescue, and stress response. The expression of such enzymes related to protein and nucleotide biosynthesis was inhibited drastically, reflecting the growth arrest of Y. lipolytica under hyperosmotic stress. The improvement of erythritol production under high osmotic stress was due to the significant induction of a range of crucial enzymes related to polyols biosynthesis, such as transketolase and triosephosphate isomerase, and the osmotic stress responsive proteins like pyridoxine-4-dehydrogenase and the AKRs family. The polyols biosynthesis was really related to an osmotic response and a protection mechanism against hyperosmotic stress in Y. lipolytica. Additionally, the high osmotic stress could also induce other cell stress responses as with heat shock and oxidation stress responses, and these responsive proteins, such as the HSPs family, catalase T, and superoxide dismutase, also had drastically increased expression levels under hyperosmotic pressure.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.181-184
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• 2002

This study reports the encapsulation of plasmid DNA in erythrocyte ghosts. The plasmid DNA was encapsulated into erythrocyte ghosts using three methods; osmotic shock, electroporation in isotonic medium, and e1ectroporation in hypotonic medium. Of three methods, electroporation in hypotonic medium resulted in the highest encapsulation efficiency of plasmid DNA. The morphology of erythrocyte ghosts prepared by electroporation in hypotonic medium was similar to that by osmotic shock alone. The circulation time of plasmid DNA in mice was prolonged by administration in erythrocyte ghost-encapsulated forms. These results indicated the potential of erythrocyte ghosts for biocompative nonviral delivery system of therapeutic genes for hematological diseases.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.841-843
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• 2002

Pfu DNA polymerase from Pyrococcus furiosus was expressed in the E. coli periplasm, and the fully active polymerase was partially purified by applying osmotic shock, ammonium sulfate precipitation, and heat treatment. This method represents a new way of expressing and purifying functional Pfu DNA polymerase without the use of chromatography.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.231-236
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• 2004

The inexpensive large-scale production of pure PGA (Penicillin G Acylase) has been a commercial goal. PGA has been used as a model enzyme in the development of simple one-step purification methods. In this study, the purification of poly-His tagged PGA protein secreted into the periplasmic space was carried out by using immobilized metal-ion affinity chromatography (IMAC). The PGA gene was obtained from E. coli ATCC 11105. Codons encoding histidines were fused at the C-terminus of the PGA gene by PCR. E. coli JM109 harboring pPGA-HIS6 vector produced active his-tagged acylases in the presence of lac promoter during cultivation at $26^{\circ}C$. The maximum specific activity of the acylase purified by using one-step chromatography after osmotic shock was 38.5 U/mg and was recovered with the yield of 70％. Both 23 kDa ($\alpha$) and 62 kDa ($\beta$) subunits were recovered by using IMAC with just C-terminus tagging of the $\beta$ subunit. The purification of the periplasmic fraction by osmotic shock and that of purified acylase was increased by 2.6-fold and 19-fold, respectively, compared to the crude extract.

• Korean Journal of Agricultural Science
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• v.32 no.1
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• pp.71-80
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• 2005

Phytic acid chelates excellently the metallic ions and the positive ions, especially has high affinity with $Fe^{2+}$ and $Ca^{2+}$. Merits of phytic acid can be taked in easily, edibile and harmless to body, so it was investigated that phytic acid can be substituted for EDTA in this study. 1. The Intensificative effect of chelating agent and disinfective osmotic shock of Vibrio vulnificus The number of initial existent fungi measured $1.7{\times}10^6$. The percentages of the survival fungi against the osmotic shock by distillated water were calculated at 1 minute, 3 minute and 5 minute after inoculation. The percentages of the survival fungi in $Mg^{2+}$ were 92.5%, 91.8% and 79.8% at each time, the average percentage was 88%. Also the sudden extinction was observed around 1 minute after inoculation and the survival fungi were not observed from 3 through 5 minute in spite of repeated experimentation. 2. Influence of Vibrio vulnificus on the survival of the mice. The first mouse started to die in 180 minute after inoculation in case that the inoculating number was $2.3{\times}10^7cfu/ml$. All died within 4.5 hour. The average of survival time was 226 minute. The first mouse started to die in 228 minute after inoculation in case that the inoculating number was $0.8{\times}10^6cfu/ml$. All died within 5 hour. The average of survival time was 300 minute and the survival time was 1.3 times high. The tendencies of death in two cases were similar, but the fatal rate were largely dependent on inoculating number.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.154-160
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• 1986

In order to develope interspecific fusion of the genus Cellulomonas capable of assimilation cellulose, the optimun conditions for the protoplast formation was investigated to examine the susceptibility of cell wall, between different species of the same genus using scanning electron microscope. The variation in the susceptibilities of Cellulomonas sp. CS 1-1 and C. flavigena to lysozyme treatment were considerably remarkable, although they belong to the same genus. The rate of protoplast formation of CS1-1 was 99.9% being treated with lysozyme $(100{\mu}g/ml)$ for 30 minute and that of C. flavigena was about 80% being treated at the concentration of $600{\mu}g/ml$ of lysozyme for 6 hours. The susceptibility of cell wall to the lysozyme treatment on protoplast formation of the strain, CS1-1 seems not to be depend on the cultural periods of cells. On the contrary, that of C. flavigena was considerably depend on the periods. Cells of C. flavigena at mid exponential phase could be more efficiently converted to protoplast cells than those at late exponential phase be done. The rate of the protoplast formation was 95%, when cells of C. flavigena at mid exponential phase were treated with lysozyme $600{\mu}g/ml$ for 6 hours and observed by SEM. In the evalution of protoplast formation of the CS1-1 results of counting method in plate after osmotic shock treatment were similar to the results of the direct observation method by means of SEM. But in the case of C. flavigena the latter method was much more reliable than the former, because the differences between the number of spheroplasts and protoplasts were not able to figure out on conuting the number of protoplast after osmotic shock tretment.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.355-356
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• 2000

Three 'stress probe' plasmids were constructed and characterized which utilize a green fluorescent protein (CFP) as a non-invasive reporter to elucidate Escherichia coli cellular stress responses in quiescent or 'resting' cells. Facile detection of cellular stress levels was achieved by fusion of three heat shock stress protein promoter elements, those of the heat shock transcription factor ${\sigma}^{32}$, pretense subunit ClpB, and chaperone DnaK, to the reporter gene $gfp_{uv}$. When perturbed by chemical or physical stress (such as heat shock, nutrient (amino acid) limitation, addition of IPTG, acetic acid, ethanol, phenol, antifoam, and salt (osmotic shock), the E. coli cells produced GFPuv which was easily detected from within the cells as emitted green fluorescence. A temporal and amplitudinal mapping of these responses was performed, demonstrating regions where quantitative delineation of cell stress was afforded.

• Genomics & Informatics
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• v.7 no.1
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• pp.26-31
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• 2009

Heat shock proteins are a class of molecular chaperones that can be found in nearly all organisms from Bacteria, Archaea and Eukarya domains. Heat shock proteins experience increased transcription during periods of heat induced osmotic stress and are involved in protein disaggregation and refolding as part of a cell's danger signaling cascade. Heat shock protein, Hsp20 is a small molecular chaperone that is approximately 20kDa in weight and is hypothesized to prevent aggregation and denaturation. Hsp20 can be found in several strains of Proteobacteria, which comprises the largest phyla of the Bacteria domain and also contains several medically significant bacterial strains. Genomic analyses were performed to determine a common evolutionary pattern among Hsp20 sequences in Proteobacteria. It was found that Hsp20 shared a common ancestor within and among the five subclasses of Proteobacteria. This is readily apparent from the amount of sequence similarities within and between Hsp20 protein sequences as well as phylogenetic analysis of sequences from proteobacterial and non-proteobacterial species.