• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.187-193
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• 2005

In an effort to optimize tissue culture conditions for genetic transformation of tall fescue (Festuca arundinacea Schreb.), an efficient plant regeneration system from seed-derived calli was established. MS medium containing 6 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.1 mg/L benzyladenine (BA) were optimal for embryogenic callus formation from mature seed and had a strong effect on successive plant regeneration. The plant regeneration frequency above 50% was observed when embryogenic calli induced in this medium were transferred to N6 medium supplemented with 1 mg/L 2,4-D and 3 mg/L BA. Among several basic media, MS and N6 medium were optimal for callus induction and plant regeneration, respectively. 'Kentucky-31' showed to have high frequencies of embryogenic callus induction and plant regeneration up to 58.3 and 50%, respectively. Addition of sucrose to the regeneration medium as a carbon source increased regeneration frequency up to 55%. A short tissue culture period and high-frequency regeneration system established in this study will be useful for molecular breeding of tall fescue through genetic transformation.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.127-134
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• 2005

Although the bulk composition of materials is one of the major considerations in extractive metallurgy and environmental science, surface composition and topography control surface reactivity, and consequently play a major role in determining metallurgical phenomena and pollution by heavy metals and organics. An understanding of interaction mechanisms of different chemical species at the mineral surface in an aqueous media is very important in natural environment and metallurgical processing. X-ray photoelectron spectroscopy (XPS) has been used as an ex-situ analytical technique, but the material to be analyzed can be any size from $100\;{\mu}m$ up to about 1 cm. It can also measure mixed solids powders, but it is impossible to ascertain the original source of resulting x-ray signals where they were emitted from, since it radiates and scans the macro sample surface area. The study demonstrated the ability of TOF-SIMS to detect individual organic species on the surfaces of mineral particles from plant samples and showed that the TOF-SIMS techniques provides an excellent tool for establishing the surface compositions of mineral grains and relative concentrations of chemicals on mineral species.

• Applied Biological Chemistry
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• v.47 no.4
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• pp.379-383
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• 2004

For the elucidation of substrate specificity to the brown copra meal by Bacillus sp. ${\beta}-mannanase.$, the enzymatic hydrolysate after 24 hr of reaction was heated in a boiling water bath for 10 min, and then centrifuged to remove the insoluble materials from hydrolysates. The major hydrolysates composed of D.P 5 and 7 galactosyl mannooligosaccharides. For the separate of galactosyl mannooligosaccharides, the supernatant solution of 150 ml was put on a first activated carbon column. The column was then washed with 5 l of water to remove mannose and salts. The oligosaccharides in the column were eluted by a liner gradient of $0{\sim}30%$ ethanol, at the flow rate of 250 ml per hour. The sugar composition in each fraction tubes was examined by TLC and FACE analysis. The combined fraction from F3 was concentrated to 30 ml by vacuum evaporator. Then put on a second activated carbon column. The oligosaccharides in the column were eluted by a liner gradient of $0{\sim}30%$ ethanol (total volume: 5 l), at the flow rate of 250 ml per hour. The eluent was collected in 8 ml fraction tubes, and the total sugar concentration was measured by method of phenol-sulfuric acid. The major component of F2 separated by 2nd activated carbon column chromatography were identified $Gal^3Man_4(6^3-mono-{\alpha}-D-galactopyranosyl-{\beta}-mannotetraose)$. To investigate the effects of brown copra meal galactomannooligosaccharides on growth of Bifidobacterium longum, B. bifidum were cultivated individually on the modified-MRS medium containing carbon source such as $Gal^3Man_4$, compared to those of standard MRS medium.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.169-177
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• 2005

This study focuses on investigating roles of microorganisms in decontamination of reed rhizosphere in Sunchon Bay, Korea, which is considered one of the marsh and mud environment severely affected by human activities such as agriculture and fisheries. In general, the bay is known to play the role of the buffering zone to reduce the sudden impact or change by environmental stresses. In our initial efforts to elucidate the microbial functions in decontamination process in reed rhizosphere, pure bacteria capable of degrading aromatic hydrocarbons were isolated from reed (Phragmites communis) rhizosphere of Sunchon bay by enrichment culture using either benzene, toluene, ethylbenzene, or xylene (BTEX) as a sole source of carbon and energy. Measurement of the rates of BTEX degradation and cell growth during the incubation in BTEX media under several temperature conditions demonstrated maximized degradation of BTEX at $37^{\circ}C$ in both strains. Both strains were also resistant to all the heavy metals and antibiotics tested in this study, as well as they grew well at $42^{\circ}C$. Identification of the isolates based on 16S rRNA gene sequences, and a variety of phenotypic and morphologic properties revealed that the two strains capable of BTEX catabolism were among Microbacterium sp., and Rhodococcus sp. with over $95{\%}$ confidence, designated Microbacterium sp. EMB-1 and Rhodococcus sp. EMB-2, respectively This result suggested that in the rhizosphere of reed, one of major salt marsh plants they might play an important roles in decontamination process of reed rhizosphere contaminated with petroleum such as BTEX.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.101-105
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• 2008

Enterobacter sakazakii is implicated in severe forms of neonatal infections such as meningitis and sepsis. This organism has been isolated from a wide range of foods, including cheese, vegetables, grains, herbs, and spices, but its primary environment is still unknown. Generally, dried infant milk formula has been epidemiologically identified as the source of E. sakazakii. Sunsik (a powdered mixture of roasted grains and other foodstuffs) is widely consumed in Korea as a side dish or energy supplement. Sunsik is consumed without heat treatment; thus, lacking an additional opportunity to inactivate foodborne pathogens. Therefore, its microbiological safety should be guaranteed. In this study, the prevalence of E. sakazakii was monitored in 23 different sunsik component flours, using FDA recommended methods; but E. sakazakii medium (Neogen) and Chromogenic E. sakazakii medium (Oxoid) were used as the selective media. In total, presumptive E. sakazakii strains were isolated from 8 different sunsik powders. Subsequently, an API 20E test was conducted, and 15 strains from 5 different sunsik flours (sea tangle, brown rice, non-glutinous rice, cheonggukjang, dried anchovy) were confirmed as E. sakazakii. Fifteen strains were again confirmed by PCR amplification, using three different primer sets (tDNA sequence, ITS sequence, 16S rRNA sequence), and compared to ATCC strains (12868, 29004, 29544, 51329). They were once again confirmed by their enzyme production profiles using an API ZYM kit. Finally, RAPD (random amplified polymorphic DNA)-genotyping was carried out as a monitoring tool to determine the contamination route of E. sakazakii during processing.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.86-91
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• 1989

To investigate the effect of NaCl concentration and nitrogen sources in the medium for the Streptococci on the intra- and extracellular proteinase(ICP and ECP) which have been known as one of the major causes for the bitter peptide formation, Streptococcus lactis $ML_8$ and Streptococcus cremoris $ML_4$ strains were incubated at 0-4% NaCl in the medium and Na-caseinate as a nitrogen source 0-100%, and the cell growth, ICP and ECP activities were analyzed. As the concentration of the NaCl in the medium increased, the growth and ECP activity decreased but the ICP $activity/10^{10}$ cells increased on the contrary. This implied that the NaCl in the medium affects only the ECP which is associated mainly to the cell wall and cell membrane but not the ICP activity. When the content of the caseinate instead of other low molecular nitrogen sources were increased in the medium, the cell growth was lowered while the ECP activities increased probably by induction of proteinase production.

• Korean journal of communication and information
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• v.29
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• pp.43-71
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• 2005

The study attempts to introduce 'Gotcha Journalism' to the Korea journalism, research and analyze it. Gotcha journalism is the journalistic reporting attitude that the journalists repeatedly and intensively reports public figures, especially politicians' mistakes or happening. 'Gotcha' is abbreviation of "I got you", frequently used in the English and American culture. In order to get the goal of this study, several journalists who are currently working for Chosun, Joongang, Dong-a, Hangyore, Kyunghyang and Seoul, national covering daily newspapers. In addition, the reporters who work for KBS, MBC, and SBS were Interviewed. All journalists who have been worked more than 5 years at the politic department were selected as interviewees. Thus, Intensive interviews are prime source of this study. Based the result of the research, gotcha journalism is externally derived from obsessive interest of Korean people to politics. Internally, it is easy to report happening or mistakes rather than big argument or ideological agenda of the politicians as news for journalists and to catch readers. In addition, the competition with advertising income accelerates this situation. And gotcha journalistic reporting behavior or attitude highly relates to political propensity of the newspapers or broadcastings. Especially some of the newspapers take gotcha journalism as a political struggling tool. It is appeared that another major cause for gotcha journalistic reporting behavior is customer-driven news production.

• Applied Biological Chemistry
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• v.19 no.4
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• pp.189-201
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• 1976

In an effort to develop a microbial in secticide, B. thdringiensis var. thuringiensis was cultured in the medium composed of cocoon-cooked water from a filature. The results obtained are summarized as followss : (1) Bacillus thuringiensis is a bacterium producing a ${\delta}-endotoxin$ especially toxic to lepidopterous insects and a thermostable exotoxin harmful to dipterous insects. (2) With a view to utilizing the cocoon-cooked water discarded from the filature, as a nutrient source in the B. thuingiensis culture, it was analyzed to contain large amounts of various minerals and protein (7.5 mg/ml) believed to be extracted from the pupae. (3) A large amount of the ${\delta}-endotoxin$ can be obtained most cheeply by using cocoon-cooked water instead of distilled water in preparing GYS and citrate salts media. (4) The largest amount of a mixture of the vegetative cells, spores, and crystals was obtained by addition of 8 gr/l of glucose to the GYS medium. (5) The growth of the bacterium was far better, when leucine, isoleucine, and valine were added all together to the citrate salts medium to the concentration of $1.25{\times}10^{-3}M$. (6) The best growth was observed by addition of Na-glutamate to the citrate salts medium to the concentration of $2.5{\times}10^{-3}M$. (7) The optimal culture time ranged from 9 to 15 days. (8) The highest mortality was shown in Pieris rapae Linne with a pH of the total body extract of 8.4, whereas Dendrolimus spectabilis Butler and Bombyx mori Linne with lower pH's were less susceptible to the ${\delta}-endotoxin$. (9) The presence of the thermo stable exotoxin was confirmed by the fact that the supernatant of the culture was very toxic to the Drosophila melanogaster tested.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.167-174
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• 2012

Transport of marine debris between countries is a potential source of diplomatic conflicts. U-i Island in Shinan County, Jeonnam Province has been reported by media as being damaged by marine debris from foreign countries. However, scientific researches on those marine debris have not been published. So, the features of foreign marine debris on Seongchon Beach in U-i Island were surveyed on Feb. 2012. The ratio of marine debris from foreign countries was 34.7% by number of items, 56.3% by weight, and 48.5% by volume in $200m^2$ transacts. Most of them, 98.9% in number, were inferred to be originated from China. The most abundant items were plastic beverage bottles and black floats. The total number of black floats was 539 within the 1,100m beach. Fifteen of them had information on manufactured locations, of which 87.6% were Liaoning Province in northern China. As domestic policy cannot prevent the inflow of the marine debris from foreign countries, countermeasures should be sought out from the international cooperation with the neighboring countries. For the black floats, recycling method should be developed as lots of the same types of black floats are drifted ashore in winter. And, as the U-i Island is a National Park with its valuable natural heritages, methods should be designed to minimize impacts on dune topography and ecology.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.232-237
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• 2015

The water supplied from dental unit water systems (DUWS) in dentistry may be heavily contaminated with bacteria and thus may be a potential source of infection for both practice staff and patients. The aim of this study was to evaluate the level of heterotrophic bacteria and to confirm the presence of opportunistic pathogens from DUWS in student clinical simulation laboratory of college of dentistry. Water samples were collected from 36 ultrasonic scalers in student clinical simulation laboratory. The levels of heterotrophic bacteria in water samples were quantified by counting colony forming units (CFUs) on R2A agar media. In addition, opportunistic pathogens were detected by using the polymerase chain reaction (PCR) method. The mean CFUs were 16,095 CFU/ml for water samples and all of water samples exceeded current American Dental Association recommendations of 200 CFU/ml. Pseudomonas species and non-tuberculous Mycobacterium species were detected in the one sample and two samples, respectively, among the 36 water samples by the PCR with specific primers for these bacteria. Our study indicated that DUWS in student clinical simulation laboratory can cause potential infection in students and participants. This study suggested the dental unit water line management and wearing personal protective equipment in student clinical simulation laboratory will be needed to reduce bacterial contamination.