• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.166-171
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• 2002

The genus Leuconostoc is generally recognized as a favorable microorganism associated with a good taste of Kimchi and Lactobacillus plantarum is responsible for the overripening and acidification of Kimchi. A rapid and reliable PCR-based method to monitor the change of these lactic acid bacterial populations during Kimchi fermentation was attempted. A Leuconostoc-specific primer set was chosen from the conserved sequences of 16S rRNA genes among Leuconostoc species. The Lb. plantarum-specific primer set was the internal segments of a Lb. plantarum-specific probe which was isolated after randomly amplified polymorphic DNA (RAPD) analysis and tested for identification. The specificity of this protocol was examined in DNA samples isolated from a single strain. In agarose gel, as little as 10 pg of template DNA could be used to visualize the PCR products, and quantitative determination was possible at the levels of 10 pg to 100 ng template DNA. For the semi-quantitative determination of microbial changes during Kimchi fermentation, total DNAs from the 2 h-cultured microflora of Kimchi were extracted for 16 days and equal amounts of DNA templates were used for PCR. The intensities of DNA bands obtained from PCR using Leuconostoc-specific and Lb. plantarum-specific primer sets marked a dramatic contrast at the 1 ng and 100 ng template DNA levels during Kimchi fermentation, respectively. As the fermentation proceeded, the intensity of the band for Leuconostoc species increased sharply until the 5th day and the levels was maintained until the 11 th day. The sharp increase for Lb. plantarum occurred after 11 days with the decrease of Leuconostoc species. The results of this study indicate that Leuconostoc species were the major microorganisms at the beginning of Kimchi fermentation and reach their highest population during the optimum ripening period of Kimchi.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.809-814
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• 2003

${\beta}-amyloid$ ($A{\beta}$) peptides from the proteolytic processing of ${\beta}-amyloid$ precursor protein (${\beta}-APP$) aggregates in the brain to form senile plaques, and their aggregation plays a key role in pathogenesis of Alzheimer's disease (AD). To isolate an active compound that has an $A{\beta}$ aggregation-inhibitory activity, 2,000 microbial metabolite libraries were screened based on their ability to inhibit $A{\beta}$ aggregation by using both Congo red and thioflavin T assays. As a result, a water-soluble fraction of a soil microorganism, KK565, showed a potent $A{\beta}$ aggregation-inhibitory activity. The strain was identified as Streptomyces species, based on the cultural and morphological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extract. In addition, the purification of active principle resulted in identifying a heat-unstable protein responsible for the $A{\beta}$ aggregation-inhibitory activity.

• Journal of the Korean Society of Tobacco Science
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• v.2 no.1
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• pp.17-27
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• 1980

From 143 sources of collected samples, the distribution of nicotinophiles were investigated and the biological characteristics as well as the rate of nicotine degradation were determined for the selected 34 strains which could grow successfully in the nicotine media, and one of the most effective strains was chosen and identified at the species level. Nicotinophils were distributed abundantly in the soils rich with organic materials, tobacco seed and root. The selected 34 strains were classified into 7 genus and identified with 4 strains of Arthrobacter, 11 strains of non-pigmented Pseudomonas, 2 strains of pigmented Pseudomonas, 6 strains of Alkaligenes, 5 strains Chromobacter 2 strains of Listeria and 4 strains of Achromobacter. Pseeudomonas and Alkaligenes were better than other genus in the rate of nicotine degradation and tobacco seed and root were also good sources for the isolation of effective nicotinophiles. Amnog 34 strains, strain NCT 27 which exhibited 97.l% of nicotine degradation rate was the best one for nicotine degradation and was indentified with Pseudomonas putida.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• The Journal of the Korean dental association
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• v.56 no.9
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• pp.462-478
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• 2018

The presence of implant-prosthesis misfits can cause various complications. It is very important to detect misfits to prevent such complications. There are various evaluation methods for misfit assessment including clinical methods and laboratory in vitro methods. The clinical misfit evaluation includes radiographic analysis, visual observation, probing, Sheffield test, evaluation with disclosing materials, and screw resistance test. The laboratory in vitro evaluation method includes indirect modelling evaluation and direct metrological visualization. Of the indirect modelling methods, photoelastic stress analysis, finite element analysis, strain gauge analysis, and microbial colonization analysis were reviewed. Of the direct metrological visualization, microscopic analysis, 3-D photogrammetric analysis, coordinate measuring analysis, and radiographic analysis were reviewed. In this review, the characteristics, advantages and disadvantages of each method were evaluated.

• KSBB Journal
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• v.14 no.6
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• pp.682-687
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• 1999

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. In order to investigate the function of VB-C as inducer in other strains, Streptomyces erythraeus was used as a test strain(parent). VB-C binding receptor gene was introduced into S. erythraeus(transformant) and the production of VBs and specific VB-C binding protein were analysed in parent and transformant. When 300ng/ml of the synthetic VB-C was added at 0, 20, 44 h cultivation of the parent and at 44 h cultivation of the transformant, the initial production times a antibiotics were shortened by more than 8 and 6 h, respectively. The transformant showed strong antibiotic activity against B. subtilis. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in S. erythraeus.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.1
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• pp.1-14
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• 2020

The latest definition of a prebiotic is "a substrate that is selectively utilized by host microorganisms conferring a health benefit"; it now includes non-food elements and is applicable to extra-intestinal tissues. Prebiotics are recognized as a promising tool in the promotion of general health and in the prevention and treatment of numerous juvenile diseases. Prebiotics are considered an immunoactive agent, with the potential for long-lasting effects extending past active administration of the prebiotic. Because of its extremely low risk of serious adverse effects, ease of administration, and strong potential for influencing the composition and function of the microbiota in the gut and beyond, the beneficial clinical applications of prebiotics are expanding. Prebiotics are the third largest component of human breast milk. Preparations including galactooligosaccharides (GOS), fructooligosaccharides (FOS), 2'-fucosyllactose, lacto-N-neo-tetraose are examples of commonly used and studied products for supplementation in baby formula. In particular, the GOS/FOS combination is the most studied. Maintaining a healthy microbiome is essential to promote homeostasis of the gut and other organs. With more than 1,000 different microbial species in the gut, it is likely more feasible to modify the gut microbiota through the use of certain prebiotic mixtures rather than supplementing with a particular probiotic strain. In this review, we discuss the latest clinical evidence regarding prebiotics and its role in gut immunity, allergy, infections, inflammation, and functional gastrointestinal disorders.

• Textile Coloration and Finishing
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• v.11 no.2
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• pp.19-26
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• 1999

Strains degrading and decolorizing acid dyes, Nylosan red E-BL 150%. were isolated from natural system, was named as ARK3. The optimal culture conditions of temperature and pH were $35^\circ{C}$, 7.0, respectively. Growth rate of cells in conditions of aerobic shaking more than standing culture conspicuously increased, and optical density of those to strain ARK3 were found as 1.38 and 0.25 after 42 hrs. Decolorization efficiency in batch culture which used as immobilization media to natural zeolite was 15% after 6 hrs, while suspension culture was 5%, also its of immobilization and suspension culture were 90% and 85% after 48 hrs, respectively. Decolorization efficiency of air-lift bioreactor was more than 90% to a dilution rate of $0.038hr^{-1}$, but that was decreased as 70%, when the dilution rate was $0.05hr^{-1}$. Even though at maximum dilution rate of this study, there was not appeared "wash out" phenomienon of biomass. Decolorization efficiency was 97.7% at a dilution rate of $0.025hr^{-1}$, when influent dye concentration was $100mg/\ell$. But if influent dye concentration increased as $150mg/\ell$, even though MLVSS increased, that of treatment water decreased as 93%. Also, when influent dye concentration increased as $200mg/\ell$ and $300mg/\ell$, decolorization efficiencies of treatment water abruptly decreased as 85% and 63%, respectively. Decolorization efficiency was more than 92% to the limit volumetric loading rate of $3.75mg/\ell\cdot{hr}$hr, without regard to variation of influent dye concentration or hydraulic retention time. if volumetric loading rate was more than $3.80mg/\ell\cdot{hr}$, at same condition, decolorization efficiency was lower decrease of retention time than increase of influent dye concentration.entration.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.785-790
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• 2013

The purpose of this study was to investigate the hazards from onions and their cultivation areas. A total of 32 samples were collected from onion farms and tested for biological (sanitary indicators, and pathogenic bacteria and fungi) and chemical (heavy metals and pesticide residues) hazards. Aerobic bacteria and coliforms were detected at a level of 0.2-7.1 log CFU/g (or mL) in the soil and agricultural water, 1.6-3.6 log CFU/g on surface of the onion, 0.0-6.0 log CFU/hand (or $cm^2$) on the workers' hands, clothes, and gloves, and 4.7 log $CFU/cm^2$ on the onion bags. Fungi were detected at a level of 0.0-5.0 log CFU/g (or mL, hand, or 100 $cm^2$) in all the samples. Staphylococcus aureus was detected at a level of 1.2 log CFU/hand on the workers' hands, the detection level of Bacillus cereus was up to 4.8 log CFU/g in the soil. However, Escherichia coli (and in particular strain O157:H7), Listeria monocytogenes, and Salmonella spp. were not detected. Although heavy metals were detected in the environment (in soil and agricultural water) and pesticide residues were detected in onion, the levels were lower than the regulation limits.

• Journal of Soil and Groundwater Environment
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• v.22 no.2
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• pp.41-51
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• 2017

Microbial processes that bind heavy metals and form minerals are widespread, and they represent a basic aspect of biogeochemistry. Some microorganisms can crystallize minerals by secreting a specific enzyme. In particular, calcite ($CaCO_3$) precipitation is an important part of biomineralization, and has been studied extensively because of its wide application in civil engineering technology. This process provides an effective way to stabilize heavy metals within a relatively stable crystal phase. In this study, biomineralization of calcite by three urea-hydrolyzing indigenous bacterial strains was investigated by microbiological analyses. Three bacterial strains were isolated from the sludge of B mine in Mexico and each bacterial strain was identified by the cellular fatty acid composition and 16S rRNA partial sequencing analysis. The results of the identification analysis showed that these strains were closest to Sporosarcina pasteurii, Kurthia gibsonii, and Paenibacillus polymyxa. We found that the optimum conditions for growth of these indigenous bacteria were $30-40^{\circ}C$ and pH range of 7-8. Microbiological analyses showed the possibility that the bioaccumulated heavy metals ions were deposited around the cell as crystalline carbonate minerals under the optimum conditions. The findings of our study suggest that the indigenous bacterial strains play an important role in heavy metal immobilization.