• Korean Journal of Microbiology
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• v.44 no.3
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• pp.244-250
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• 2008

To evaluate bacteriological water quality, samples were taken from drinking water dispensers placed at S company (S-C) and U highschool (U-H) in Ulsan. The medians of heterotrophic plate counts (HPCs) were 53 CFU/ml for the 74 water samples of S-C and 80 CFU/ml for the 36 cold water samples of U-H, and 38% of the S-C and 42% of the U-H samples showed HPC bacterial concentrations higher than 100 CFU/ml. Coliform bacteria were detected from one sample of S-C. To determine the major source of bacterial contamination, water samples were taken daily for $6\sim8$ days from the bottled water containers as well as the faucets of an experimental water dispenser. While the average HPCs in the bottled water containers were 33 CFU/ml for the first and 132 CFU/ml for the 2nd analysis, the HPC concentration in the cold water samples was 1,022 CFU/ml for the 2nd analysis. These results suggest that the majority of bacteria detected in the cold water samples were originated from the biofilms on the surface of water passages within the water dispensers. There was no significant increase in HPC bacterial concentrations within the bottled water container after installation on the water dispenser. We could isolate and tentatively identify 3 genera 6 species of Gram-positive and 7 genera 7 species of Gram-negative bacteria from the plate count agar plates of U-H samples. Among the isolates, 72% were observed as Gram-positive, and Micrococcus spp. was the most abundant with 54% of the total, followed by Sphingomonas paucimobilis with 16%. It appears that most of the HPC bacteria detected in water dispensers originate from indoor airborne bacteria, which may play important roles in the formation of biofilms on the surface of water passages within the water dispensers.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.217-224
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• 2005

This study was aimed to analyze the long-term fluctuation of water quality and phytoplankton dynamics of Paldang reservoir in Korea and to assess the relationship between algal bloom patterns and hydrological, limnological data. Diatoms in Paldang reservoir occurred continuously through the year. Blue- green algae occurred during the summer season (from June to Sept.), and the highest count was observed in July. Occurrence pattern of green algae was similar to that of blue-green algae. The rest of algae contained a lot of Cryptomonas spp. whose concentration was high from May to Aug. Dominant algal genera (>>7,000 cells $mL^{-1}$) in Paldang reservoir were Aulacoseira, Cyclotella, Microcystis, and Cryptomonas spp. Microcystis and Anabaena occurred during the summer season. Many different green algal genera were found in Paldang reservoir but their abundances were very low. There were some significant correlations (r>0.3, p<0.05) between algal taxa and water quality; diatoms and water temperature, TP:blue-green algae and water temperature, pH, DO saturation, COD, TP; green algae and water temperature, pH, DO saturation, COD, SS, TP. Furthermore, algal genera and water quality was significantly correlated (r>0.3, p<0.05) ; Aulacoseira and TN, TP; Anabaena and water temperature, DO saturation, COD, TP : Microcystisand water temperature, pH, DO saturation, TP; Coelastrum and COD, SS; Scenedesmus and water temperature, COD, TN, TP; Cryptomonas and DO saturation, TN. In Paldang reservoir, the water temperature had relatively big effect on blue-green algal bloom that was also dependant upon its hydrologic condition.

• The Korean Journal of Mycology
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• v.23 no.3 s.74
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• pp.202-208
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• 1995

This study describes the effects of several components on PCR amplification used for RAPD. We used different concentrations of reaction components to obtaine discrete and reproducible PCR products from Pleurotus cornucopiae. The optimum concentrations of reaction components were found to be 80 ng of template DNA, 30 pmole of 10-mer primer, $200\;{\mu}M$ dNTP, 2mM $MgCl_2$, 50 mM KCl, 10 mM Tris-HCl(pH 9.0), 0.1% Triton X-100, 1.5 unit of Taq DNA polymerase (promega) in $50\;{\mu}l$ reaction volume. The optimum annealing temperature was $35^{\circ}C$. These results proved to be valuable for characterization of Pleurotus spp.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.483-488
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• 2008

Foodborne pathogenic bacteria in various food samples in Korea were monitored and the obtained data was statistically analyzed. A total of 1,240 food samples including 280 sashimi, 244 processed frozen products, 258 kimbab (cooked rice wrapped with seaweed), 337 soybean pastes were obtained from 7 cities including Seoul in Korea. Microorganisms tested were Bacillus cereus, Salmonella spp., Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Vibrio parahaemolyticus, Yersinia enterocolitica, Listeria monocytogenes, Campylobacter jejuni, and Clostridium perfringens. The contaminated microorganisms in food samples were comprised of 10.55% B. cereus, 2.7% S. aureus, 2.0% V. parahaemolyticus, 0.8% C. perfringens, 0.2% Y. enterocolitica, and 0.1% of L. monocytogenes, respectively. Salmonella spp., C. jejuni, and E. coli O157:H7 were not detected in any of the food samples. Particularly, B. cereus that harbors the enterotoxin gene was detected in various foods and regions in Korea, therefore it should be a given special consideration not to allow the hazardous level of contamination.

• Journal of Applied Biological Chemistry
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• v.44 no.3
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• pp.113-118
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• 2001

Xylose (glucose) isomerase was purified to homogeneity from cell-extracts of Streptomyces chibaensis J-59 via ammonium sulfate precipitation followed by chromatography on DEAE-cellulose, and gel filtration on Sephacryl S-300. The purified enzyme is a homotetramer with a native molecular mass of 180 kDa and a subunit molecular mass of 44 kDa. The amino acid N-terminal sequence of glucose isomerase from S. chibaensis J-59 was determined to be Ser-Tyr-Gln-Pro-Thr-Pro-Glu-Asp-Arg-Phe-Thr-Phe-Gly-Leu. The first 14 amino acids of the N-terminal sequence of the enzyme showed strong analogies with N-terminal sequences of glucose isomerase produced by other Streptomyces spp. The optimum pH and temperature for activity were 7.5 and 85, respectively. The purified enzyme required $Mg^{2+}$, $Co^{2+}$, and $Mn^{2+}$ for the activity, $Mg^{2+}$ being the most effective. The enzyme was not inhibited by $Ca^{2+}$, but was inhibited by $Hg^{2+}$, $Ag^+$, and $Cu^{2+}$. The $K_m$, $V_{max}$, and $k_{cat}$ values of S. chibaensis J-59 isomerase for glucose were 83 mM, 40.9 U/mg, and $1,843min^{-1}$, respectively. In the presence of $Co^{2+}$, cell-free enzymes retained 100% without loss of activities by the heat-treatment at $70^{\circ}C$ for 7 days. The enzyme retained 50% residual activity after heating at $85^{\circ}C$ for 13.5 h, at $90^{\circ}C$ for 126 min. The enzyme is more thermostable than any other glucose isomerases of Streptomyces spp.

• Macromolecular Research
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• v.17 no.5
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• pp.332-338
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• 2009

Rheological behavior of natural hydrogel produced from seeds of three Salvia spp. (S. miltiorrhiza (SM), S. sclarea (SS), S. viridis (SV)) was investigated by using a Rheometer equipped with a cone and plate geometry measuring system under never-dried condition. Different chemical contents of such hydrogels give significant effects on their rheological properties. Because of incomplete penetration of water inside the hydrogels after drying before-dried hydrogels were used for rheological analysis. To know molecular interactions which predominated in the gel formation, some constituents were externally added to the 1.0% (w/w) hydrogel. Addition of urea to disrupt hydrogen bonds reduced 3.4-67% viscosity of the untreated hydrogels and changed viscoelastic properties from gel to liquid-like behavior. Neutral salts added to the hydrogel solution at 0.1 M also lowered the viscosity in a manner related with increase in size of cations and temperature. Changing from gel state to liquid-like state was also easily confirmed by oscillation measurement (storage, G', and loss, G", modulii) typically observed in the cases of potassium sulfate and potassium thiocyanate. Influence of pH variation on the viscosity explained that weak alkaline condition (pH 8-9) creates a higher resistance to flow due to increasingly electrostatic repulsions between negative charges ($COO^-$) Importance of calcium bridges was also demonstrated by recovery of viscosity of the hydrogels by addition of calcium after acidification. The summarized results indicate that electrostatic repulsion is a major contributor for production of hydrogel structure.

• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.268-278
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• 2013

Objectives: The purpose of this study was to apply the Hazard Analysis Critical Control Point (HACCP) system to the production of seasoned laver products. The hazard analysis examined microbial evaluations and developed a HACCP management plan through the heating process. Methods: In this study we chose three companies and performed the analysis thrice. During this study, general bacteria along with other food poisoning bacteria such as Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, E.coil, O157:H7, Vibrio parahaemolyticus, were studied at varying temperatures from 100 to $300^{\circ}C$. Results: The presence of general bacteria was detected in raw laver in the samples analyzed from all the three companies, and the number ranged from $10^5-10^7$. Bacillus cereus was detected in samples from only two of the three companies analyzed. However, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, E.coil, O157:H7, and Vibrio parahaemolyticus were all negative. General bacteria was reduced to $10^5$ after being subjected to temperatures of $100-250^{\circ}C$, but heating to over $270^{\circ}C$ reduced the number to below $10^3$, and the other microbes such as Bacillus cereus were not detected. Conclusions: In conclusion, the heating process ($270-280^{\circ}C$) along with RPM of 100-1200 were identified as CCP to reduce biological hazards.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.576-582
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• 2002

Probiotics are live microbial feed supplements which beneficially affect the host animal by improving its intestinal microflora. To select the best Lactobacillus spp. as a chicken probiotic, probiotic characteristics of 10 selected Lactobacillus strains isolated from chicken cecum or obtained from KCTC were investigated. The strains were examined for resistance to pH 2.0 and 0.3% oxgall, and adhesion to cecal mucus and cecal epithelial cells. All strains grew in MRS containing 0.3% oxgall. However, Lb. plantarum AYM-10, Lb. fermentum YL-3, AYM-3, and Lb. paracasei YL-6 showed relatively high resistance to 0.3% oxgall. Lb. fermentum YL-3, YM-5, AYM-3, and Lb. paracasei YL-6 survived 4 hours of incubation at pH 2.0. Lb. fermentum YL-3, KCTC 3112, and Lb. plantarum AYL-5 were strongly adhesive to cecal mucus, while the rest showed moderate or low adhesion. Lb. plantarum AYM-10, AYL-1, and AYL-5 had good adhering properties to cecal epithelial cells (30.7$\pm$10.82, 40.2$\pm$20.90, and 14.5$\pm$4.22, respectively). Lb. fermentum YL-3, AYM-3, and KCTC 3547 showed Intermediate adhesion ability, and Lb. plantarum showed better adhesion ability to cecal epithelial cells than Lb. fermentum. Attached Lb. fermentum YL-3 to cecum after 60 min incubation was confirmed using CLSM. Lb. fermentum YL-3 attached to a matrix which was composed of a mucus layer adjacent to intracrypts and pericryptal region. Some Lb. fermentum YL-3 bound to mucosal epithelial cells. From these results, Lb. fermentum YL-3 was selected as a chicken probiotic. In vivo trials of chicks inoculated with Lb. fermentum YL-3 had decreased Salmonella population in cecal contents and livers (p<0.5).

• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.473-480
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• 2008

A high incidence of Anisakiasis has been reported in many countries where people eat frequently raw or undercooked seafood. Anisakis spp. larvae were obtained from the mackerel acquired from a fish market of Cheongju city. They were divided into several groups and placed in culture dishes containing RPMI-1640 (culture media), in the presence or absence of different concentrations of herbal extracts (Meliae ezadarach, Dryopteris crassirhizoma, Quisqualis indica var villosa). The objective of the present study was to investigate the activity of larval migration inhibition in vitro. Meliae ezadarach at the concentrations of 7.5, 15, and 30 mg/ml effectively inhibited the larvae migration in time-dependent manner during experimental period of 0-24 h. Treatment of Meliae ezadarach at the three concentrations completely inhibited the larvae migration in vitro. Dryopteris crassirhizoma at the concentrations of 5, 10, and 20 mg/ml also effectively inhibited the larvae migration in a time-dependent manner. The treatment of Dryopteris crassirhizoma for 12 h completely inhibited the larvae migration. The inhibitory effect of Dryopteris crassirhizoma was stronger than that of Meliae ezadarach. Although Quisqualis indica var villosa also showed the inhibitory effect on larvae migration, its inhibitory efficacy was the weakest among tested herbal extracts. These results indicated that some herbal extracts may be useful in controlling human anisakiasis.

• Korean Journal of Microbiology
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• v.37 no.3
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• pp.214-220
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• 2001

To develop the effective composting system, we isolated bacteria that have the abilities to degrade organic matters such as cellulose, carbohydrate, protein and lipid during the compositing of livestock manureAmong 24 strains, 6 bacteria have all the enzymatic activities of protease, amylase, cellulase and lipase.These microorganisms were identified as Corynebacterium varibilis, Bacillus spp., Pseudomonas spinosa,Acetobacter calcoaceticus and Athrobacter cumminsii All the enzymes produced by the bacteria showedactivities at the broad pH range and the maximal activities were obtained at $60^{\circ}C$. It seemed that after theincrease of temperature caused by fermentation of livestock manure, the enzymes started to degrade the rawmaterials, which are added for the control of humidity. However cellulase activity was maximum at $37^{\circ}C$,suggesting that the cellulase-producing bacteria work at an early stage of livestock manure fermentation toprovide the organic material for the growth of other bacteria. The production of the enzymes were growth-associated and maximal activities appeared at the early stationary phase of growth.