• Korean Journal of Microbiology
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• v.37 no.4
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• pp.253-258
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• 2001

A Bacillus circulans KCTC3004 $\beta$-1,3-glucanase gene contained in a recombinant plasmid pLM460 derived from subcloning the original recombinant plasmid pLM530 was trasferred into a new shuttle vector plasmid pLMS1180 by ligating linearized DNAs of pLM460 and pUB110. B. subtilis RM125 and B. megaterium ATCC14945 transformed with pLMS1180 produced the $\beta$-1,3-glucanase substantially. Most of the enzyme was produced during the exponential growth period. The maxium activities of the $\beta$-1,3-glucanase produced by the Bacillus transformants were compared with that of the B. circulans gene donor strain. The B. subtilis RM125 (pLM1180) enzyme showed the activity 14 times higher than that of the gene donor cells, followed by the B. megaterium ATCC14945 (pLMS 1180) enzyme with activity 5 times higher than that of the gene donor cells. While E. coli secreted about 7% of the produced enzyme, B. subtilis excreted the enzyme into the medium wholly and B. megaterium about 97% of the total product. The SDS-PAGE of this enzyme produced in E. coli (pLMS1180), B subtilis (pLMS1180) or B. megaterium (pLMS1180) indicated a molecular weight of 38,000. The enzymes overproduced in three different host cells hydrolyzed laminarin to produce mainly laminaribiose, laminaritriose, and laminarioligosaccharides. The plasmid pLMS1180 was stable in B. megaterium, E. coli, but was unstable in B. subtilis.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.7-12
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• 1999

By SDS-polyacrylamide gel elcctrophoresis (SDS-PAGE) and immunoblot analysis that a protein with 66,000 daltons in size was recognized by P. aeruginosa anti-exotoxin A from P. sp. PY002. The yields of exotoxin A in P. sp. PY002 culture were influenced by the concentration of iron in the culture media. Increasing of the exotoxin A production and siderophore production was made slight increasing in the MKB medium. On the other hand, to clone the gene encoding the exoloxin A genomic library of P. sp. PY002 was constructed in pBluescript SK(+). From this library a exotoxin A homologous gene was isolated by immunological hybridization method using P. aemginosa anti-exoloxin A as a probe. Two putative clones were isolated and designated pETA23 and pETA42. Thc restriction analysis ol pETA42 demonstrated that thc 1760 bp insert contained one NcoI, PvuII, SstI, Kpnl and EcoRI site and three SmaI and HaeD sites.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.86-95
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• 2015

To study the halobacterial diversity at the rhizospheric soil of coastal plant native to Dokdo islands, several host plant were selected and its rhizospheric soil was sampled. Soil sample was diluted serially and pure isolation was done by sub-culture using marine agar media. 26 halophilic strains cultivable at the marine medium containig concentration of 9.0% sodium chloride were selected among total 161 isolates. Their partial 16S rRNA gene sequences extracted from genomic DNA were analyzed and partially identified. Furthermore, to identify their genetic relationship, phylogenetic tree was deduced. Total 26 strains were belongs to Firmicutes (30.8%), Gamma proteobacteria (53.8%), Bacteroidetes (7.7%), Alpha proteobacteria (7.7%), and Actinobacteria (7.7%). These results showed the specific difference from previous researches which has been reported the microbial flora of soil or sea water around the Dokdo islands. Furthermore, 4 among 26 halophilic strains grew at above 12.0% NaCl concentrated marine broth, and 2 strains Idiomarina abyssalis LM4H23 and Halomonas huangheensis AS4H13 grew at 15.0% concentration. These halophilic strains thought to overcoming the severe stress like high salt concentration or variation derived from Dokdo-specific climate and might have unknown, specific relationship with their host coastal plant native to Dokdo islands.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.153-159
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• 2017

We isolated 120 strains of wild yeasts from the water and riverside soils of Daejeoncheon and Gapcheon in Daejeon, Korea. We identified Debaryomyces udenii JSF601, Kazachstania telluris JSF602, Trichosporon faecale JSF614, Candida infanticola WJSL0039, Candida palmioleophila WJSL0048, Pichia spartinae WJSL0087, and Trichosporon coprophilum WJSL0093 from Daejeoncheon, and Leucosporidium golubevii WJSL0108 and Ustilentyloma graminis WJSL0118 from Gapcheon, as newly recorded yeast strains in Korea and investigated their microbiological characteristics. All of these previously unrecorded yeasts were oval- or ellipsoidal-shaped with ascospores, except C. infanticola WJSL0039, C. palmioleophila WJSL0048, and D. udenii JSF601. L. golubevii WJSL0108 and U. graminis WJSL0118 grew in vitamin-free medium, and C. infanticola WJSL0039 was halotolerant and grew in 10% NaCl-containing YPD broth. K. telluris JSF602 and P. spartinae WJSL0087 were thermophilic yeasts, which grew at $37^{\circ}C$.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.105-109
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• 2007

This study was carried out to investigate the biological effects oak wood vinegar. Antimicrobial activity was tested in five microbial species at the concentration of 5 to $50{\mu}l$ of oak wood vinegar by paper disc method. Growth of P. oleovoranse, P. vulgaris, E. coli, S. aureus and Prevotella intermedia was inhibited at a dose of as low as $50{\mu}l$ of oak wood vinegar. Antioxidant activities were measured by using DPPH radical scavenging and SOD-like activity. DPPH radical scavenging and SOD-like activities were 90% and 65% at the concentration of $25{\mu}l\;and\;50{\mu}l$ of oak wood vinegar, respectively. Stimulation of the macrophages RAW264.7 cells with lipopolysaccharide (LPS) resulted in increased production of nitric oxide (NO) in the medium. However, the oak wood vinegar showed marked inhibition of NO synthesis in a dose-dependent manner. This result suggest that oak wood vinegar plays significant role for activation of immune system in the pathogenesis of inflammatory diseases.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.157-161
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• 2010

Photosynthetic purple nonsulfur bacterial strains were isolated from the sediments collected from rice paddy fields and sludges of wastewater treatment plant, and their plant growth promoting capabilities were examined. Most well known phytohormones, auxin such as indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) and 5'-aminolevulinic acid (ALA) were detected by HPLC in the culture broth of these isolates. Among the isolated bacteria, Rhodopseudomonas faecalis D15 showed the highest production rate of 769.8 ${\mu}g$/mg protein of IAA, 1323 ${\mu}g$/mg protein of IBA and 7.4 mM/mg protein of ALA in the modified Biebl and Pfennig's medium. R. faecalis C9 showed the highest production rate of 20.82 ${\mu}g$/mg protein of gibberellin. In consequence, the root length and dry weight of the germinated tomato seedling treated with R. faecalis isolates were longer and heavier than those of uninoculated control after 15 days of incubation in the soil. Especially, the dry weight of germinated tomato seedling increased by 119.4% in C9-treated samples after 15 days. These purple nonsulfur bacteria may be utilized as environment-friendly biofertilizer in the agriculture.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.79-83
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• 2000

Activated sludge samples were collected from a municipal sewage treatment plant and used for enrichment of microbial consortia with aniline as the sole carbon and nitrogen source. Threc aniline-degrading bacteria were obtained lrom microbial consortia and an isolate which has excellent aniline degradability was selected for this study. The isolate was Gram-negative, and identified and designated as Delfha sp. JK-2 on the basis of various physiological and biochemical tests. 10 mM aniline was completely degraded within 24 hours after inoculation of the culture. Ammonium ion was liberated in the medium transiently during the incubation and disappeared when aniline was completely degraded. Addition of glucose as a supplementary source to aniline minimal media showed significant decrease in aniline degradat~on rate for the strain Effective degradation of aniline was achieved by the addition of 0.5% nitrate as a nitrogen source, and resulted in approximately 80% higher aniline degradation compared to the absence of nitrate. Phylogenetic analysis based on 16s [DNA sequence revealed that the strain was closely related to De@ia acidovorans, with 96% overall similarity. The 16s [DNA sequence of JK-2 was also found to be closely related to those of six other clonal types, including Acidovoru, Aquaspirillum. Xylophilus, Variovorm, and Rhodofernr.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.155-160
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• 2000

Pseudomnas sp. HJ-2 is capable of producing a rubber-elastic polyhydroxyalkanoate (PHA) consisting of 3- hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyheptanoate (3HHp) from heptanoic acid as the sole carbon source. The polyester produced was a blend of poly(3HB-co-3HV) and poly(3HHp). Although the mixing of poly(3HHp) fraction to poly(3HB-co-3HV) resulted in a decrease of modulus, the sole fraction of poly(3HB-co-3HV) with a high molar fraction of 3HV was shown to be an elastomer with the maximum percent strain of 740%. The biomass yield and the PHA synthesis were relatively high when the initial heptanoic acid concentration was 40 mM, and were significantly decreased when the substrate concentration exceeded 50 mM. The accumulation of PHA was stimulated by deficiency of nitrogen and phosphorus in the medium. The PHA contents and its monomeric compositions were greatly affected by pH and oxygen transfer rate. At pH 7.5, poly(3HB-~0.38% 3HV) was produced from heptanoic acid and a mixture of 95% 3HHp and 5% 3HV was produced at pH 8.0. Increased conten1 of 3HHp in the polyesters with lhe increasing oxygen transfer rate by agitation speed a1 a fixed aeration rate was observed.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.181-186
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• 2003

This study was performed to analyze quantitatively the number of living bacteria in forest soil samples collected from Mt. Keryong using improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria by DVC comprised 18～44% of the total direct count (TDC), whereas the number of living bacteria by PC was less than 1% of TDC. These results showed that viable but non-culturable (VBNC) bacteria existed in the soil with high percentages. Besides, DVC was proved to make it possible to make a quantitative detection of the VBNC bacteria. On the other hand, upon measuring the value from the conventional nutrient broth (NB) and $10^{-2}$ folded diluted nutrient broth (DNB), the values from the DNB showed 5 to 10 times higher than those from the conventional NB medium. These results indicate that oligotrophic bacterial groups, which could multiply in the low nutrient broth, abundantly exist in the soil ecosystem. It would also be possible to apply this kind of method to other substrate to make a quantitative detection of soil bacterial groups.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.148-154
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• 2003

Moraxella sp. CK-l is known to inhibits the growth of Anabaena cylindrica, a cyanobacterium. It has been documented that the ability of this growth inhibition of Anabaena cylindrica was attributed to extracellular autolysin from Moraxella sp. CK-l. However, it remains to be elucidated identification and characterization of autolysin have yet been elucidated. In this study, we tried to purify and identify autolysin secreted from Moraxella sp. CK-l. Cells were grown in a complex liquid medium (BGC-11) and culture supernatants were collected, followed by ammonium sulfate fractionation. Fractions were further separated with anion exchange column, Mono-Q, in FPLC system and analyzed by SDS/PAGE. The fraction containing high autolysin activity showed a single distinct protein peak in anion column and molecular mass of about 17 kDa in SDS/PAGE. Nterminal amino acid sequencing of the protein was analyzed, of which result showed the homology with some proteases, including extracellular serine protease, Dichelobacter nodosus.