• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.174-179
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• 2006

Bacterium capable of using biphenyl as a sole source of carbon and energy were isolated from soil, and based on the results of 16S rDNA sequence, strain BK10 identified as a Sphingobium yanoiktiyae. The optimum cultural conditions were as follows; $NH_4NO_3$ 1g, $K_2HPO_4$ 1g, $MgSO_4{\cdot}7H_2O$ 0.5g, $CaCO_3$ 0.2 g per 1 liter of distilled water. The Sphingobium yanoikuyae BK10 strain was completely utilized biphenyl in mineral salt media containing biphenyl at concentration 500 $\mu$g/ml of biphenyl as a sole carbon and energy source within 48 hours. Optimumal pH and temperature for biphenyl degradation and cell growth of strains were 6.0$\sim$8.0 and 20$\sim$50$^{\circ}C$, respectively. Especially, at 30$^{\circ}C$, cell-growth were higher than other temperature. Cell grown on biphenyl has been shown to have a higher removal rate for biphenyl than grown on sucrose. This study shows that Sphingobium yanoikuyae BK10 strain had a high biodegradation capability of biphenyl and can be simulate a candidate compounds the bioremediation of PCBs (Polychlorinated biphenyl) contaminant soil and water.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.197-203
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• 2009

An indole oxygenase originated from Rhodococcus sp. RHA1 was cloned into the expression vector, pTrc99A, in Escherichia coli, and designated pTCAN1. The pTCAN2 was constructed from pTCAN1 by the deletion of $lacI^q$ for the constitutive expression of indole oxygenase without adding IPTG in the medium. The complete open reading frame of indole oxygenase was 1,224 bp long, which encodes a protein of 407amino acids. Crude extracts of E. coli $DH5{\alpha}$/pTCAN1 and pTCAN2, respectively, were prepared and subjected to SDS-PAGE analysis. A band corresponding to molecular mass of about 43 kDa was appeared and this result correlated with the predicted molecular mass of cloned indole oxygenase. The E. coli harboring pTCAN1 and pTCAN2, respectively, showed blue color colony in LB plate. The pigment showing blue color was prepared from E. coli $DH5{\alpha}$/pTCAN2, and identified as indigo by experiments using spectrophotometer, HPLC, and TLC. The indigo-forming activity of indole oxygenases from the whole cell of E. coli $DH5{\alpha}/pTCAN1$ cultured at LB medium added 1mM of IPTG and that of E. coli/pTCAN2 showed about 1.75nmol/min/mg DCW (dry cell weight) and 3.85 nmol/min/mg DCW, respectively. Also, the E. coli $DH5{\alpha}$/pTCAN2 produced about $236{\mu}M$ of indigo after 48 hours incubation in TB medium supplemented with 2.5 mM of tryptophan.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.434-441
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• 2009

Ferroportin-1 (FPN) is a transporter protein that is known to mediate iron export from macrophages. The purpose of this study was to investigate the effect of copper on the regulation of FPN gene expression in J774 mouse macrophage cells. J774 cells were treated with various concentrations of $CuSO_4$ and RT-PCR analyses were performed to measure the steady-state levels of mRNAs for FPN and divalent metal transporter 1 (DMT1, an iron importer). Copper treatment significantly increased FPN mRNAs in a dose-dependent manner, but didn't change the levels of DMT1 mRNA. Experiments with transcriptional inhibitor actinomycin D (0.5 ${\mu}g$/mL) revealed that copper treatment did not affect the half-life of FPN mRNAs in J774 cells. On the other hand, results from luciferase reporter assays showed that copper directly stimulated the promoter activity of FPN. In summary, our data showed copper induced FPN mRNA of macrophages via a transcriptional rather than post-transcriptional mechanisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.46-54
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• 1997

Sporulation in the fission yeast Schizosaccharomyces pombe has been regarded as an important model of cellular development and differentiation. S. pombe cells proliferate by mitosis and binary fission on growth medium. Deprivation of nutrients especially nitrogen sources, causes the cessation of mitosis and initiates sexual reproduction by malting between two sexually compatible cell types. Meiosis is then followed in a diploid cell in the absence of nitrogen source. DNA fragment complemented with the mutations of sporulation gene was isolated from the S. pombe gene library constructed in the vector, pDB 248' and designated as pDB (spo 5)1. We futher analyzed six recombinant plasmids, pDB (spo 5)2, pDB(spo 5)3, pDB(spo 5)4, pDB(spo 5)5, pDB(spo 5)6, pDB(spo 5)7, and found each plasmids is able to rescue the spo 5-2, spo 5-3, spo 5-4, spo 5-5, spo 5-6, spo 5-7, mutations, respectively. Mapping of the integrated plasmid into the homologous site of the S. pombe chromosomes demonstrated that pDB (spo 5)1, and pDB (spo 5)R1 contained the spo 5 gene. Transcipts of spo 5 gene were analyzed by Northern hybridization. Two transcripts of 3.2 kb and 25 kb were detected with 5 kb Hind III fragment containing a part of the spo 5 gene as a probe. The small mRNA (2.5 kb) appeared only when a wild-type strain was cultured in the absence of nitrogen source in which condition the large mRNA (3.2 kb) was produced constitutively. Appearance of a 2.5 kb spo 5-mRNA depends upon the function of the mei1, mei2 and mei3 genes.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.299-305
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• 2006

In this study, we have isolated and identified a proteolytic bacterium from conventional Cheongkukjang. We also characterized several bioactivity of Cheongkukjang, which was fermented by an isolated strain. One strain out of about $10^4$ strains obtained from Cheongkukjang showed relatively high proteolytic activity was selected and named as a Bacillus subtilis LSH805 strain. White soy-bean Cheongkukjang possessed less odor and more viscous substance than black soy-bean Cheongkukjang. Cheongkukjang showed fibrinolytic activity, and about 1,500 mg fibrin was degraded after 20 h incubation. Although nitric oxide (NO) assays of soy-bean and Cheongkukjang were almost the same, their activities were significantly higher than that of no treatment. Activity of water fraction of Cheongkukjang was somewhat higher than that of soy-bean. Fibrinolytic and NO assays of Cheongkukjang suggest that Cheongkukjang, which was fermented by an isolated strain may be a useful candidate for natural fibrinolytic and macrophage-stimulating agents.

• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.297-304
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• 1997

Effects of cultural conditions on the production of xylanase by Tremella fuciformis, symbiotic fungi and mixed fungi were investigated. The optimum carbon source for high production of xylanase by T. fuciformis, symbiotic fungi and mixed fungi was xylose. The optimum nitrogen source for both T. fuciformis and symbiotic fungi was $KNO_3$, whereas mixed fungi was $(NH_4)_2SO_4$. The optimum culture period for high production of xylanase was 5 days for both T. fuciformis and mixed fungi, and 6 days for symbiotic fungi, respectively. The optimum temperature for T. fuciformis and symbiotic fungi was $40^{\circ}C$, and the corresponding value for mixed fungi was $45^{\circ}C$. Xylanase activity was high at pH 6 for T. fuciformis and symbiotic fungi, and pH 7 for mixed fungi. Except $Hg^{2+}$ and $Pb^{2+}$, metal ions in T. fuciformis inhibited the activity of xylanase, and, thermal stability of xylanase in T. fuciformis, symbiotic fungi and mixed fungi maintained 80% of activity until $50^{\circ}C$. The Michaelis constant (Km) of xylan was $6.25{\times}10^{-5}\;M$ in T. fuciformis, $5.6{\times}10^{-2}\;M$ in symbiotic fungi, $5.2{\times}10^{-2}\;M$ in mixed fungi.

• The Korean Journal of Mycology
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• v.20 no.3
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• pp.240-251
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• 1992

To find antitumor components from higher fungi, the cultured mycelia of Paxillus atrotomentosus were extracted with hot water. The water soluble fraction was purified and separated by DEAE-cellulose ion exchange chromatography and Sepharose CL-4B gel filtration method. The separated fractions(Fr.) were designated CR A, B, C and D. Fr. A showed the highest inhibition ratio of 68.51% among the five tractions at a dose of 20 mg/kg/day. When Fr. A was examined for immunopotentiation activity, it increased the amount of the superoxide anion from activated macrophages to 1.1 fold and the number of plaques in hemolytic plaque assay to 2.3 fold, respectively. Otherwise, it did not show direct cytotoxity in sarcoma 180. Delayed type hypersensitiyity reaction showed that the decreased footpad swelling of tumor-hearing was restored to the normal. These results indicate that antitumor activity was exerted through immunopotentiation. Its chemical analysis showed 86.36% polysaccharide, 1.52% protein and 1.64% hexosamine. The polysaccharide consisted of fucose, galactose, glucose, mannose and xylose. This component was named paxillan.

• The Korean Journal of Mycology
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• v.9 no.2
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• pp.93-97
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• 1981

The new strains of Mycogone perniciosa which could attack cream colored mushroom were collected and tested to find out their characteristics in comparison with the original strains. The optimum temperature for mycelial growth was $25^{\circ}C$, showing no difference between strains, but optimum pH was 6.0 for the original strains and pH 7.0 for the new ones. New strains did not survive at $50^{\circ}C$ for 60 minutes while original ones 40 minutes. Delan and Hamai were effective for controlling new strains and the mushroom strains which have scales showed resistance to the new strains of Mt. perniciosa regardless of the mushroom colors.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.76-82
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• 2003

To prepare evolved PHB depolymerase with increased activity for PHB or P(3HB-co-3HV) compared to the activity of the original PHB depolymerase from Alcaligenes faecalis T1, random mutation of the cloned PHB depolymerase gene was performed by using a DNA shuffling method. A library of mutated PHB depolymerase genes from A. faecalis T1 was fused to the ice nucleation protein (INP) gene from Pseudomonas syringae in pJHCl 1 and approximately 7,000 transformants were isolated. Using M9 minimal medium containing PHB or P(3HB-co-3HV) as the carbon source, mutants showing alteration in PHB depolymerase activity were selected from the transformants. The PHB depolymease activity of the transformants was confirmed by the formation of halo around colony and the turbidity decrease tests using culture supermatants. The catalytic activity of PHB depolymerase of the best mutant II-4 for PHB or P(3HB-co-13 mol% 3HV) was approximately 1.8-fold and 3.2-fold, respectively, higher than that of the original PHB depolymerase. DNA sequence analysis revealed that three amino acid residues (Ala209Val, Leu258Phe, and Asp263Thr) were substituted in II-4. From the mutational analysis, it was presumed that the substitution of amino acids near catalytic triad to more hydrophobic amino acids enhance the catalytic activity of PHB depolymerase from A. faecalis T1.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.448-452
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• 2015

The bacterial strain that was isolated from chinese cabbage rhizosphere, showed inhibition of yeast growth. This strain was identified as Pseudomonas fluorescens BB2 by API 20NE test and 16S rRNA gene sequence analysis. P. fluorescens BB2 strain produced antibiotics against yeast as a secondary metabolite effectively when the culture was carried out in YM medium with 3% glucose at $20^{\circ}C$. The protein antibiotic of BB2 strain which was concentrated by ammonium sulfate precipitation and n-butanol extraction inhibited the growth of yeast with the minimal inhibitory concentration of $10{\mu}g/ml$ against Candida albicans KCTC 7965, and the growth of yeast was completely inhibited at $80{\mu}g/ml$. The hydrophilic fraction of n-butanol extraction inhibited the growth of Bacillus cereus ATCC 21366, showed orange halo on chrome azurol S plate, which means the fraction contained iron chelating siderophore. The results of crystal violet uptake through the cell membrane showed that membrane permeability was increased about 9% than control, when the concentration of hydrophobic antibiotic against yeast C. albicans was $60{\mu}g/ml$. As a result, the antibiotic produced by P. fluorescens BB2 against yeast Candida is considered antimicrobial peptide, and this is the first report in the genus Pseudomonas.