Publications by authors named "DuBok Choi"

Recently, polyhydroxyalkanoates (PHAs) have been produced using raw sewage in our laboratory; however, the production concentrations are low. Therefore, this study aimed to enhance PHA production by applying different strategies. PHA production was higher in sewage-containing medium than in mineral salt medium and was enhanced 22-fold after glucose supplementation.

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With the growing interest in bioplastics, there is an urgent need to develop rapid analysis methods linked to production technology development. This study focused on the production of a commercially non-available homopolymer, poly(3-hydroxyvalerate) (P(3HV)), and a commercially available copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB--3HV)), through fermentation using two different bacterial strains. The bacteria and sp.

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To evaluate the wound-healing effect of epidermal growth factor (ApEGF), we performed the sequence analysis, cloning, and prokaryotic expression of cDNA from the ApEGF gene, examined the transcriptional changes, and investigated the wound-healing effect of this protein in cells and rat epidermis. Primers were designed based on available sequence information related to the ApEGF gene in a public database, and part of the ApEGF sequence was obtained. The full-length cDNA sequence of ApEGF was obtained using inverse PCR.

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The aim of this work was to evaluate the synthesis and structure-activity relationship of 4-((2,4-dioxothiazolidin-5-ylidene)methyl)phenyl 2-phenylacetate derivatives as potential wound-healing agents. The IC values of the lead compounds ranged from 0.01 to 0.

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Effective biological pretreatment method for enhancing cellulase performance was investigated. Two alkali lignin-degrading bacteria were isolated from forest soils in Japan and named CS-1 and CS-2. 16S rDNA sequence analysis indicated that CS-1 and CS-2 were Bacillus sp.

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Excessive scar formation is an aberrant form of wound healing and is an indication of an exaggerated function of fibroblasts and excess accumulation of extracellular matrix during wound healing. Much experimental data suggests that prostaglandin E₂ (PGE₂) plays a role in the prevention of excessive scarring. However, it has a very short half-live in blood, its oxidization to 15-ketoprostaglandins is catalyzed by 15-hydroxyprostaglandin dehydrogenase (15-PGDH).

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Four strains of biphenyl-degrading bacteria were isolated from a sewage and identified from the Rhodococcus genus (SK-1, SK-3, and SK-4) and Aquamicrobium genus (SK-2) by 16S rRNA sequence. Among these strains, strain SK-2 was most suitable for biphenyl degradation. When 0.

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For biological extraction of heavy metals from chromated copper arsenate (CCA) treated wood, different bacteria were investigated. The extraction rates of heavy metals using Lactobacillusbulgaricus and Streptococcusthermophilus were highest. The chemical extraction rates were depended on the amounts of pyruvic acid and lactic acid.

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The effects of a water-soluble tacrolimus-PEG conjugate (KI-102) on insulin-dependent diabetes mellitus and systemic lupus erythematosus were investigated. KI-102 was stable at pH 4.0-4.

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Two rapidly growing propionibacteria that could reductively dechlorinate tetrachloroethylene (PCE) and cis-1,2-dichloroethylene (cis-DCE) to ethylene were isolated from environmental sediments. Metabolic characterization and partial sequence analysis of their 16S rRNA genes showed that the new isolates, designated as strains Propionibacterium sp. HK-1 and Propionibacterium sp.

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A fibrinolytic enzyme has been purified from the fruiting bodies of Korean Cordyceps militaris. The molecular mass of the enzyme was estimated to be 34 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fibrin-zymography, and gel filtration chromatography. The 15 amino acid residues of the N-terminal sequence of the enzyme were APVEQCDAPVGLARL, which is dissimilar to those of fibrinolytic enzymes from other mushrooms.

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Biochemical and enzymatic properties of a fibrinolytic enzyme purified from Pleurotus eryngii cultivated under solid-state conditions using corn cob as energy source were investigated. The molecular mass of the enzyme was estimated to be 14 kDa by SDS-PAGE. The enzyme exhibited the highest activity (28.

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In this study, the effects of the FK506-mPEG on immune cell activity, skin grafting rejection, and Freund's complete adjuvant arthritis were investigated. The proliferation of T cells was inhibited with increase with the FK506 and FK506-mPEG concentrations. FK506 and FK506-mPEG at concentrations between 0.

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A marine bacterium was isolated from seawater near the Korean south coast for efficient saccharification from alginate. Based on 16S rDNA sequence, the isolated strain was identified as Pseudoalteromonas agarovorans. Various environmental factors affecting saccharification of alginate using P.

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For effective exopolysaccharide production and mycelial growth by a liquid culture of Fomitopsis pinicola in an air-lift bioreactor, the culture temperature, pH, carbon source, nitrogen source, and mineral source were initially investigated in a flask. The optimal temperature and pH for mycelial growth and exopolysaccharide production were 25degrees C and 6.0, respectively.

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Using a 50-l airlift bioreactor, for the effective production of tylosin from Streptomyces fradiae TM-224 using raw cornmeal as the energy source, various environmental factors were studied in flask cultures. The maximum tylosin concentration was obtained at 32 degrees C and pH between 7.0 and 7.

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