• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.435-442
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• 2001

Poly(3-hydroxy-5-phenylvalerate) [P(3HPV)] was efficiently accumulated from 5-phenylvalerate (5PV) in Pseudomonas putida BM01 in a mineral salts medium containing butyric acid (BA) as the cosubstrate. A nove aromatic copolyester, poly(5 mol% 3-hydroxy-4-phenylbutyrate-co- 95 mol% 3-hydroxy-6-phenylhexanoate) [P(3HPB-co-3HPC)] was also synthesized from 6-phenylhexanoate (6PC) plus Ba. The two aromatic polymers, P(3HPV) and P(3HPB-co-3HPC), were found to be amorphous and showed different glass-transition temperatures at $15^{\circ}C$ and $10^{\circ}C$, respectively. When the bacterium was grown ina medium containing 20 mM 5PV as the sole carbon source for 140 h, 0.4 g/l of dry cells was obtained in a flask cultivation and 20 wt% of P(3HPV) homopolymer was accumulated in the cells. However, when it was grown with a mixture of 2 mM 5PV and 50 mM BA for 40 h, the yield of dry biomass was increased up to 2.5 g/l and the content of P(3HPV) in the dry cells was optimally 56 wt%. This efficient production of P(3HPV) homopolymer from the mixed substrate was feasible because BA only supported cell growth and did not induce any aliphatic PHA accumulation. The metabolites released into the PHA synthesis medium were analyzed using GC or GC/MS. Two $\beta$-oxidation derivatives, 3-phenylpropionic acid and trans-cinnamic acid, were found in the 5V-grown cell medium and these comprised 55-88 mol% of the 5PV consumed. In the 6PC-grown medium containing Ba, seven ${\beta}$-oxidation and related intermediates were found, which included phenylacetic acid, 4-phenylbutyric acid, cis-4-phenyl-2-butenoic acid, trans-4-phenyl-3-butenoic acid, trans-4-phenyl-2-butenoic acid, 3-hydroxy-4-phenylbutyric acid, and 3-hydroxy-6-phenylhexanoic acid. Accordingly, based on the metabolite analysis, PHA synthesis pathways from the two aromatic carbon sources are suggested.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.463-473
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• 2000

This research was carried out to investigate chemical pretreatment using limestone in treating abandoned metallic mine drainage with anaerobic biological treatment, and to estimate application of papermill and livestock sludge as carbon sources for SRB (Sulfate Reducing Bacterial. Capacity of anaerobic limestone bed was steeply decreased. But if limestone was utilized as pretreatment process in treating them with anaerobic biological treatment. it could look forward to stabilize system because it did initally neutralize them. Effluent SCOD in R-4 was lower than R-l~R-3 in inital HRT 5day but its concentration was high in HRT 1day after passed time. Therefore in point of durability and supply of organic matter. it seemed that R-4 was useful became organic matter in R-4 was not consumed by excessive degradation within short period. In all reactors, pH was suitable for SRB growth in whole HRT, but on the evidence of ORP, SRB was active after HRT 2day. Fixation trend of heavy meta s showed high as $SO_4{^{2-}}$ reduction efficiency increased, and $SO_4{^{2-}}$ reduction and fixation of heavy metals were relatively high in HET 2day.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1834-1845
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• 2018

The lactobacilli associated with a fermented goat milk product from Tajikistan were isolated to characterize their technological properties and antibiotic resistances in order to assess their suitability for development as starter cultures. In this study, twenty three strains were identified by 16S rRNA sequencing as typical dairy-associated lactic acid bacterial strains, i.e. L. plantarum, L. pentosus, L. delbrueckii, L. helveticus and L. paracasei. These strains were generally susceptible to most antibiotics tested in this study and this allowed a selection of strains as safe starters. The draft genomes of four representative strains were sequenced and the number of contigs of the four assembled genomes ranged from 51 to 245 and the genome sizes ranged from 1.75 to 3.24 Mbp. These representative strains showed differences in their growth behavior and pH-reducing abilities in in vitro studies. The co-inoculation of these Lactobacillus spp. strains together with a yeast Kluyveromyces marxianus MBT-5698, or together with the yeast and an additional Streptococcus thermophilus MBT-2, led to a pH reduction to 3.4 after 48 h. Only in the case of fermentation inoculated with the co-culture, the viscosity of the milk increased noticeably. In contrast, fermentations with single strains did not lead to gelation of the milk or to a decrease in the pH after 24h. The results of this study provide a comprehensive understanding of the predominant lactobacilli related to Tajikistani fermented milk products.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.798-807
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• 2008

Due to economic impairment derived from metal corrosion of pumping station installed around coastal area, it was needed for related cause-effect to be investigated for understanding practical corrosion behavior and providing proper control. This research was thus carried out to determine whether the microbe can influence on metal corrosion along with its control in the laboratory. For this study, groundwater was sampled from the underground pump station(i.e. I Gas Station) where corrosion was observed. Microbial diversity on the samples were then obtained by 16S rDNA methods. From this, microbial populations showing corrosion behaviors against metals were reported as Leptothrix sp.(Iron oxidizing) and Desulfovibrio sp.(Sulfur reducing) Iron oxidizing bacteria were dominantly participating in the corrosion of iron, while sulfate reducing bacteria were more preferably producing precipitate of iron. In case of galvanized steel and stainless steel, iron oxidizing bacteria not only enhanced the corrosion, but also generated its scale of precipitate. Sulfate reducing bacteria had zinc steel corroded greater extent than that of iron oxidizing bacteria. In the inactivation test, chlorine or UV exposure could efficiently control bacterial growth. However as the inactivation intensity being increased beyond a threshold level, corrosion rate was unlikely escalated due to augmented chemical effect. It is decided that microbial corrosion could be differently taken place depending upon type of microbes or materials, although they were highly correlated. It could be efficiently retarded by given disinfection practices.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.56-65
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• 2006

An antagonistic bacterial isolate, that inhibits the growth of plant pathogens, was selected and identified from 5,000 isolates screened from the rhizosphere of various crop plants. An isolate Bacillus sp. N32, tested against Colletotrichum gloeosporioides causing anthracnose disease in hot pepper, produced both a heat resistant antifungal protein and a heat sensitive antifungal protein. The heat resistant protein was partially purified by Ammonium sulfate fractionation and gel filtration chromatography. The bioautography showed that the proteins possessed high antifungal activity. The biosynthetic gene cluster responsible for the heat resistant antifungal protein was cloned from cosmid library using DNA probe obtained from PCR product with the primers targeting the conserved nucleotide sequence of the synthetic genes reported earlier, Most of the clones obtained showed higher homology to fengycin antibiotic synthetic gene family reported earlier. On the other hand, the heat sensitive protein was isolated from SDS-PAGE and electroblotting to determine the N-terminal amino acid sequences. The heat sensitive antifungal protein gene was cloned from the ${\lambda}-ZAP$ libraries using a DNA probe based on the N-terminal amino acid sequences of the heat sensitive protein. We are contemplating to clone and sequence the whole gene cluster encoding the heat sensitive protein for further analysis.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.152-161
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• 2015

CodY is a highly conserved protein in low G+C gram-positive bacteria that regulates genes involved in sporulation and stationary-phase adaptation. Bacillus thuringiensis is a grampositive bacterium that forms spores and parasporal crystals during the stationary phase. To our knowledge, the regulatory mechanism of CodY in B. thuringiensis is unknown. To study the function of CodY protein in B. thuringiensis, BMB171codY^- was constructed in a BMB171 strain. A shuttle vector containing the ORF of cry1Ac10 was transformed into BMB171 and BMB171codY^-, named BMB171cry1Ac and BMB171codY^-cry1Ac, respectively. Some morphological and physiological changes of codY mutant BMB171codY^-cry1Ac were observed. A comparative proteomic analysis was conducted for both BMB171codY^-cry1Ac and BMB171cry1Ac through two-dimensional gel electrophoresis and MALDI-TOF-MS/MS analysis. The results showed that the proteins regulated by CodY are involved in microbial metabolism, including branched-chain amino acid metabolism, carbohydrate metabolism, fatty acid metabolism, and energy metabolism. Furthermore, we found CodY to be involved in sporulation, biosynthesis of poly-β-hydroxybutyrate, growth, genetic competence, and translation. According to the analysis of differentially expressed proteins, and physiological characterization of the codY mutant, we performed bacterial one-hybrid and electrophoretic mobility shift assay experiments and confirmed the direct regulation of genes by CodY, specifically those involved in metabolism of branched-chain amino acids, ribosomal recycling factor FRR, and the late competence protein ComER. Our data establish the foundation for in-depth study of the regulation of CodY in B. thuringiensis, and also offer a potential biocatalyst for functions of CodY in other bacteria.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.788-794
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• 2009

Both strains of KD-1212 and DAH-1056 were isolated and identified from animal manure-contaminated soil by screening bacterial strains for the removal of sulfur compound-malodor with such substrate as sodium thiosulfate or free sulfur. Then the characteristics on the incubation of these microbes were observed under various incubating-condition such as pH, temperature, aerobic or anaerobic, substrate(sulfur compound) concentration, nitrogen and carbon source and rotating speed for mixing, and the optimum incubating condition was established. The optimum pHs of KD-1212 and DAH-1056 were 7.0 and 4.0, respectively, and their optimum temperatures were in the range of $30{\sim}35^{\circ}C$. Another autotrophic strain, ED-1138, was isolated from contaminated soil. The strain DAH-1056 excelled a strain Thiobacillus sp. IW in eliminating hydrogen sulfide during the process of malodor-biofiltration with a fixed strain. The characteristics on the incubation of strain KD-1212 were observed under various substrate-concentrations, nitrogen and carbon sources. KD-1212 favored glucose and maltose, and yeast extract as carbon sources and nitrogen source, respectively. The optimum concentrations of substrate and nitrogen source were 25 mM of sodium thiosulfate and 0.5% yeast extract, respectively for the growth of strain KD-1212.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.4 s.48
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• pp.503-507
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• 2004

The essential oil from Chamaecyparis obtusa was investigated for biological activities in anti-oxidative, anti-inflammation and antibacterial method, respectively. The Growth inhibitory effect of C. obtusa oil on the bacteria was evaluated with MIC (minimum inhibitory concentration), $IC_{50}\;(50\%$ inhibitory concentration), and paper disc method. Two kinds of gram positive strains and two kinds of gram negative strains were used in this study. Gram positive strains were B. subtilis and S. aureus. and Gram negative strains were E. coli and P. aeruginosa. Gram positive strains showed much more intensive effect than gram negative strains. Anti-oxidative effect was investigated with DPPH (1,1-diphenyl-2-picrylhidrazyl) in methanol based and $IC_{50}\;was\;0.78\%.$ Our results suggest that the essential oil from Chamaecyparis obtusa has effects on anti-bacterial, anti- oxidative and anti-inflammation in in vitro and in uiuo. Then this material could be expect synergic effect with other candidated extracts and oils.

• Food Science and Preservation
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• v.19 no.1
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• pp.62-66
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• 2012

With the rapid growth of fresh-cut produce market, the South Korean fresh-cut industry is facing the challenge of ensuring food safety. As the estimation of the microbial numbers in fresh-cut produce processing lines (tools, and equipment) using the conventional microbiological techniques takes days, so there is a need for faster and easier monitoring methods. This study was conducted to investigate the use of ATP bioluminescence assay to measure the degree of microbial contamination from three actual fresh-cut processing lines. The samples collected from frech-cut vegetables, and fresh-cut fruits processing plants were tested for the estimation of the bacterial number, using the ATP bioluminescence and microbiological methods. The result of former was transferred to log RLU/100 $cm^2$, and that of the latter was transferred to log CFU/100 $cm^2$. A positive linear correlation between the ATP bioluminescence assay value and aerobic-plate count was found for fresh-cut processing lines, with a correlation coefficient of 0.8772 (n=50). The results of this study indicate that ATP bioluminescence assay can be used to monitor microbial contamination in fresh-cut produce processing plants, and can help improve the hygiene therein.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.123-135
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• 2001

Several growth factors and polypeptides were studied for the regeneration of periodontal supporting tissues which had been lost due to periodontal disease. But these are not commonly used for regenerators of bone tissue or alveolar bone, because of the insufficiency of studies on their side effects, genetic engineering for mass production and stability for clinical application. Recently, many natural products, which have advantage of less side effects and possibility of long-term use, have been studied for their capacity and effects of anti-bacterial, anti-inflammatory and regenerative potential or periodontal tissues. Cnidii Rhizoma, Rhinocerotis Cornu and Drynariae Rhizoma have been traditionally used as a drug for treatment of bone disease in oriental medicine. The purpose of this study was to examine the ability of alkaline phosphatase synthesis of MC3T3-E1 cells when above medicines were supplimented. MC3T3-E1 cells were cultured with ${\alpha}-MEM(negative control)$, dexamethasone(positive control), and each natural products for 3 and 5 days. And then ALP synthesis was measured by spectrophotometer for enzyme activity and by naphthol AS-BI staining for morphometry. Except Cnidii Rhizoma, all of the natural products of this study induced higher activity of ALP synthesis than controls. Among them Drynariae Rhizoma induced the highest activity. In the aspects of culturing time, all medicines did not showed the difference between 3 and 5 days, but $10^{-7}g/ml$ group of Rhinocerotis Corun showed significant increase at 3 days than at 5 days. These results indicate that several natural products have a inducing ability of ALP synthesis on osteoblasts.