• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.1-4
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• 1997

Viroid-like RNA molecules were detected from the low molecular weight RNAs isolated from the Korean peonies which showed typical viroid symptoms of epinasty and dwarfing. Low molecular weight RNAs including viroid RNA molecules were purified by the Qiagen anion exchange minicolumns. Viroid-like RNA molecules showed a single viroid specific band in the native polyacrylamide gel. They were separated into two bands in the denaturing gel conditions. The band of circular form of viroid-like RNAs was crossed over the horizontal band of the linear form of viroid-like RNA molecules in 0~8 M urea gradient gel under the denaturing conditions of 37$^{\circ}C$. The two circular forms of viroid-like RNA molecules were detected in the reverse polyacrylamide gel electrophoresis. The viroid-like RNA molecules purified from the peonies were supposed to be unidentified viroid RNA molecules.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.299-310
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• 1986

The ovine squamous cell carcinoma (OSCC)-specific and immunosuppressive properties of OSCC extracts were investigated by using the techniques of lymphocyte blastogenicity, acid dissociation-ultrafiltration and gradient polyacrylamide gel electrophoresis. It was found that OSCC extracts contained two major and one minor protein peaks by Sephadex gel fractionation. Two major peaks bear substantial amount of immunoglobulins, antigen-antibody complex and OSCC-specific fractions, and the minor peak includes immunosuppressive materials. OSCC-specific components were detected at the molecular weights of 10,000 to 100,000 daltons in the major peaks and immunosuppressive materials at the fractions with the molecular weight of 10,000 to 100,000 and < 10,000 daltons in the minor peak. When the fractions were further separated by gradient polyacrylamide gel electrophoresis, the OSCC-specific antigens were found in the slice number 4 to 6 in fraction III, and immunosuppressive materials, in the slice numbers 9 to II in fraction V. The present results were considered to provide a basis for preparation and purification of OSCC-specific and immunosuppressive materials from the crude OSCC extracts.

• Journal of Korean Society on Water Environment
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• v.29 no.5
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• pp.691-702
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• 2013

This review paper summarizes the theory, application, and potential drawbacks of diffusive gradient in thin film (DGT) probe which is a widely used in-situ passive sampling technique for monitoring inorganic contaminants in aquatic environments. The DGT probe employs a series of layers including a filter membrane, a diffusive hydrogel, and an ionic exchange resin gel in a plastic unit. The filter side is exposed to an aquatic environment after which dissolved inorganic contaminants, such as heavy metals and nuclides, diffuse through the hydrogel and are accumulated in the resin gel. After retrieval, the contaminants in the resin gel are extracted by strong acid or base and the concentrations are determined by analytical instruments. Then aqueous concentrations of the inorganic contaminants can be estimated from a mathematical equation. The DGT has also been used to monitor nutrients, such as ${PO_4}^{3-}$, in lakes, streams, and estuaries, which might be helpful in assessing eutrophic potential in aquatic environments. DGT is a robust in-situ passive sampling techniques for investigating bioavailability, toxicity, and speciation of inorganic contaminants in aquatic environments, and can be an effective monitoring tool for risk assessment.

• Korean Journal of Microbiology
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• v.14 no.4
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• pp.176-185
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• 1976

An improved procedure for the rapid purification of glucose-6-phosphate dehydrogenase from extracts of Saccharomyces cerevisiae was developed by using affinity chromatography. Among six affinty media tested, NADP$^{+}$-agarose and Affi-gel Blue were more effective than others (i.e., Affi-gel Red, AMP-agarose, ATP-agarose, and NAD$^{+}$-agarose). Conditions to desorb the enzyme bound to the affinity media were examined to increase the purity as well as yield. The best result was obtained when the column was developed with a linear gradient of KCl (0-1.0M). In case of Affi-gel Blue, introduction of NAD$^{+}$ (15mM) washing step prior to the salt gradient was most effective to remove NAD$^{+}$-binding proteins. For a large scale preparation of G-6-P dehydrogenase higher recovery was obtained by Affi-gel Blue than NADP$^{+}$-agarose, however, the purity of the enzyme was decreased by 10 times if the former was used as the affinity medium. The capacity of Affi-gel Blue for G-6-P dehydrogenase was found to be 5 times higher than that of NADP$^{+}$-agarose. Furthermore Affi-gel Blue could be reused repeatedly and its preparation is relatively easier and less expensive than NADP$^{+}$-agarose.X> +/-agarose.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.239-244
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• 1987

Low molecular weight plant ribonucleic acids including potato spindle tuber viroid(PSTV) RNA were electrophoresed in 0M to 8M urea-gradient polyacrylamide gels. The electrophoresis was carried on in a urea - gradient gel system with 1/40 and 1/10 dilution of TBE buffer at three different temperatures, $17^{\circ}C,\;37^{\circ}C\;and\;57^{\circ}C$. The most effective separation of PSTV - RNA molecules into circular and linear forms was achieved at the highly denaturing temperature of $57^{\circ}C$ and at 1/40 dilution of TBE buffer. The electrophoretic mobility of the denatured circular viroid-RNA molecules is dependent mainly on the concentration of urea. In addition, a low concentration of TBE buffer would increase the separation distance between the circular and linear forms of PSTV-RNA molecules in the denaturing urea-gradient gel system

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1057-1062
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• 2016

Kimchi is a traditional Korean fermented vegetable food, the production of which involves brining of Korean cabbage, blending with various other ingredients (red pepper powder, garlic, ginger, salt-pickled seafood, etc.), and fermentation. Recently, kimchi has also become popular in the Western world because of its unique taste and beneficial properties such as antioxidant and antimutagenic activities, which are derived from the various raw materials and secondary metabolites of the fermentative microorganisms used during production. Despite these useful activities, analysis of the microbial community present in kimchi has received relatively little attention. The objective of this study was to evaluate the bacterial community structure from the raw materials, additives, and final kimchi product using the culture-independent method. Specifically, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the 16S rRNA partial sequences of the microflora. One primer set for bacteria, 341F^GC-518R, reliably produced amplicons from kimchi and its raw materials, and these bands were clearly separated on a 35-65% denaturing gradient gel. Overall, 117 16S rRNA fragments were identified by PCR-DGGE analysis. Pediococcus pentosaceus, Leuconostoc citreum, Leuconostoc gelidum, and Leuconostoc mesenteroides were the dominant bacteria in kimchi. The other strains identified were Tetragenococcus, Pseudomonas, Weissella, and uncultured bacterium. Comprehensive analysis of these microorganisms could provide a more detailed understanding of the biologically active components of kimchi and help improve its quality. PCR-DGGE analysis can be successfully applied to a fermented food to detect unculturable or other species.

• Journal of Microbiology
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• v.42 no.1
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• pp.1-8
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• 2004

Changes in the bacterial populations of a 5-stage biological nutrient removal (BNR) process, with a step feed system for wastewater treatment, were monitored by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA fragments. DGGE analysis indicated seasonal community changes were observed, however, community profiles of the total bacteria of each reactor showed only minor differences in the samples obtained from the same season. The number of major bands was higher in the summer samples, and decreased during the winter period, indicating that the microbial community structure became simpler at low temperatures. Since the nitrogen and phosphate removal efficiencies were highly maintained throughout the winter operation period, the bacteria which still remaining in the winter sample can be considered important, playing a key role in the present 5-stage BNR sludge. The prominent DGGE bands were excised, and sequenced to gain insight into the identities of the predominant bacterial populations present, and most were found to not be closely related to previously characterized bacteria. These data suggest the importance of culture-independent methods for the quality control of wastewater treatment.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.885-892
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• 2011

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and -independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culturedependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.856-861
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• 1988

A new method developed for simultaneous purification of enterotoxin A and C from Staphylococcus aureus strain L 350/1 consisted of chromatography on carboxymethyl (CM)-cellulose using a buffer of variable pH, gel filtration on Ultro gel, and fast protein liquid chromatography(FPLC) using a buffer of variable pH. The enterotoxin A and C were purified by three steps: batchwise adsorption from culture supernatant on Amberlite CG-50; chromatography on CM-cellulose using a buffer of constant pH and molarity; and gel filtration on Sephadex G-75. The purified enterotoxin appeared homogeneous by gel diffusion and polyacrylamide gel electrophoresis. Upon treatment with CM-cellulose using a elution of variable pH, enterotoxin A and C were so close that they were not separated completely. After elution from gels, the enterotoxins appeared as a single peak at the same position. Gel filtration gave a reaction of complete identity to enterotoxin A and C in Ouchterlony immunodiffusion. In FPLC using a CM-cellulose, enterotoxin A and C were simultaneously separated at pH 8.6 and 6.8. When each fraction was performed to gel immunodiffusion, at peak of enterotoxin A and C were not detected each other. In a method of elution by pH-gradient was to be more efficient as a simultaneous separation method in terms of speed, yields and simplicity. The purified toxin A and C were identical to type A and C reference enterotoxin on both disc electrophoresis and Ouchterlony gel diffusion.

• BMB Reports
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• v.35 no.2
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• pp.236-238
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• 2002

Based on the zymography analysis, Bacillus sp. DJ-4 (screened from Doen-Jang, a Korean traditional fermented food) secretes seven extracellular fibrinolytic enzymes (EFEs; 68, 64, 55, 45, 33, 27, and 13 kDa) in culture broth. These seven EFEs were analyzed by newly applied SDS-fibrin zymography combined with gradient polyacrylamide (SDS-FZGP). This improved gel system was used with a 5-20% acrylamide gradient in a fibrin zymogram gel for the separation of proteins with molecular masses from below 10kDa to over 100kDa on one gel plate. Using this system, high molecular weight bands (HMWBs) were clearly and sharply resolved. We also examined the relationship between an acrylamide concentration and the enzymatic activity of EFE using densitometric analysis.