• Journal of Microbiology
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• v.45 no.3
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• pp.193-198
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• 2007

A marine bacterium was isolated from Mai Po Nature Reserve of Hong Kong and identified as Vibrio cholerae MP-1. It contains a small plasmid designated as pVC of 3.8 kb. Four open reading frames (ORFs) are identified on the plasmid, but none of them shows homology to any known protein. Database search indicated that a 440 bp fragment is 96% identical to a fragment found in a small plasmid of another V. cholerae. Further experiments demonstrated that a 2.3 kb EcoRI fragment containing the complete ORF1, partial ORF4 and their intergenic region could self-replicate. Additional analyses revealed that sequence upstream of ORF1 showed the features characteristic of theta type replicons. Protein encoded by ORF1 has two characteristic motifs existed in most replication initiator proteins (Rep): the leucine zipper (LZ) motif located at the N-terminal region and the alpha helix-turn-alpha helix motif (HTH) located at the C-terminal end. The results suggest that pVC replicates via the theta type mechanism and is likely a novel type of theta replicon.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.421-428
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• 1996

The occurrence, optical property, chemical composition, crystal structure and formation environments of the phillipsite within deep-sea manganese nodules were systematically investigated in this study. Phillipsite in manganese nodules occurs in nucleus of nodules along with consolidated bottom sediments, weathered volcanic debris, and interstitial grains in the each layer of manganese encrusts. Phillipsite is predominantly pseudomorphs of volcanic shards, and occurs as white to pale yellow in color lath-shaped and equant crystals. These show aggregations of prismatic, blocky, and bladed of 2 to $20{\mu}m$ long, and 2 to $5{\mu}m$ thick. The simplified average chemical formula of phillipsite is $({Ca_{0.1}Mg_{0.3}Na_{1.1}K_{1.5}})_3{(Fe_{0.3}Al_{4.2}Si_{11.8})O_{32}{\cdot}10H_2O}$ with a very siliceous and alkalic. The $Si/(Al+Fe^{+3})$ ratio is 2.37 to 2.78 and alkalis greatly exceed the divalent exchangeable cations, and Na/K ratio is 0.59 to 0.81. The phillipsite is monoclinic ($P2_l/m$) with the unit-cell parameters, $a=10.005{\AA}$, $b=14.129{\AA}$, $c=8.686{\AA}$, ${\beta}=124.35^{\circ}$, and $V=1013.6{\AA}^3$. Phillipsites in manganese nodules formed apparently authigenically at a temperature less than $10^{\circ}C$, and they crystallized at a pressure of less than 0.7 kb, and pH of about 8 in deep-sea environments.

• Journal of fish pathology
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• v.23 no.3
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• pp.335-342
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• 2010

In 2008, mass mortality was observed in paradise fish Macropodus opercularis which was imported from Indonesia. PCR of these fish found positive for megalocytivirus and Mycobacterium sp., while an unidentified virus was culture-isolated using CHSE-214 cells. In the present study, we investigated characterization of the unidentified virus and its pathogenicity to determine whether the virus was the causative agent of the mass mortality of paradise fish. The unidentified virus induced cytopathic effect (CPE) with syncytia in CHSE-214 and other fish cells, BF-2, GF, SSN-1, FSP and FFN. The virus was resistant against treatments with IUdR, chloroform, acidity at pH 3, basicity at pH 11 and high temperature at $56^{\circ}C$ for 3h. By electron microscopy, the viral particles were spherical having a double capsid structure with approximately 65 nm in external diameter. Viral genome was composed of at least 10-segmented RNA with sizes ranging from 0.7 kb to 3.6 kb. Based on these characters, this virus can be classified into family Reoviridae. This reovirus did not cause any mortality in an artificial experiment conducted by injecting the virus to paradise fish. This indicates that the reovirus is not only responsible for the mass mortality of paradise fish in 2008.

• Journal of Microbiology and Biotechnology
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• v.4 no.2
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• pp.102-107
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• 1994

The $\beta$-1,4-endoglucanase gene from Actinomyces sp. 40 was cloned into Escherichia coli DH5$\alpha$ with pUC19. Chromosomal DNA from Actinomyces sp. 40 was cleaved with the restriction enzyme Sau3AI and ligated into pUC19 for the transformation of Escherichia coli DH5$\alpha$. Positive clones of $\beta$-1,4-endoglucanase gene were detected as the clear zones on a medium supplemented with carboxymethylcellulose (CMC). This transformant possessed a single plasmid, designated pDS1, which contained the vector DNA and a 3.5 kilobase (kb) Sau3AI insertion fragment encoding endoglucanase. The size of the cloned fragment was reduced to 2.0 kb. The endoglucanase activity produced by the E. coli DH5$\alpha$ (pDS6) was higher than that of Actinomyces sp. 40 strain. The optimum pH and temperature of the cloned enzyme were pH 4.0$\sim$5.0 and 55$^{\circ}C$, respectively. The cloned enzyme was stable at 55$^{\circ}C$ or below and in buffer ranging from pH 4.0 to 7.0. The enzyme degraded CMC but did not degrade xylan, cellobiose, and methyl-umbelliferylcellobiopyranoside (MUC).

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.307-313
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• 2008

The yeast surface expression system, pCTXYN (6.8 kb), of Bacillus endoxylanase gene (xynB, 642 bp) was constructed and introduced into Saccharomyces cerevisiae EBY100 cell. The transformed yeast cell showing the highest endoxylanase activity was selected through the active staining of colonies grown on YPDG medium containing xylan. With the yeast transformant, EBY100/pCTXYN, grown on galactose containing medium, it was found that the endoxylanase was successfully displayed on the yeast cell surface and the xylooligosaccharides were efficiently produced from xylan. The most of endoxylanase activity was detected in the cell fraction and reached about 1.9 unit/mL after 48 h cultivation. The optimized conditions for xylooligosaccharides production from xylan were determined as follows: substrate and its concentration, oat spelt xylan 6%; concentration of yeast whole-cell, 5 unit/mL; temperature, $50^{\circ}C$, and reaction time $2{\sim}4\;h$. When the oat spelts xylan and corncob xylan were hydrolyzed by treatment with cell surface-displayed endoxylanase, xylotriose was formed as a main product.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.60-66
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• 2004

The cycloinulooligosaccharide fructanotransferase(CFTase) gene (cft) from Paenibacillus polymyxa was subcloned into the E. coli-yeast shuttle vector, pYES2.0 (GALI promoter). The constructed plasmid, pYGCFT (9.9 kb) was introduced into S. cerevisiae SEY2102 cell and then the yeast transformant was selected on the synthetic defined media lacking uracil Based on the cyclofructan(CF) spots on thin-layer chromatogram, the gene under the control of GALI promoter was successfully expressed in the yeast transformant. The recombinant CFTase was not secreted into the medium and was predominantly localized in the periplasmic space. CF was started to be produced after 3h of enzymatic reaction with inulin. The pH and temperature optimum for the CF production from inulin was pH 8.0 and 45$^{\circ}C$, respectively. Enzyme activity was stably maintained up to the pH of 10.0. The examination of the inulin sources revealed that a dahlia tuber and Jerusalem artichoke were the best for the production of CF.

• Korean Journal of Microbiology
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• v.36 no.1
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• pp.46-51
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• 2000

Salmonella typhi is one of important causes of human enteric infections. S. typhi KNIH100 was isolated from a patient of typhoid fever in Korea. We cloned a 5.0 kb SalⅠ fragment containing the aroA gene encoding a 5-enolpyruvylshikimate-3-phosphate synthetase from chromosomal DNA of this strain. This recombinant plasmid was named pSAL80. E. coli CGSC2829, an aroA- mutant, was not grown on the M9 minimal medium but E. coli CGSC2829 (pSAL80) was grown on the M9 minimal medium. The aroA gene was composed of 1,284 base pairs with ATG initiation codon and TAA termination codon. Sequence comparison of the aroA gene exhibited 99%, 98%, and 77% identity with those of S. typhi Ty2, S. typhimurium, and E. coli respectively. As in the cases of Shigella sonnei and E. coli, the serC and aroA genes lie in a single operonic structure.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.531-536
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• 2007

The aerial part of Artemisia iwayomogi Kitamura has traditionally been used for inflammation, infectious disease, cancer, pyretic, diuretic, liver protective effect, and choleretic purposes in Korea. We investigated that the essential oil induces apoptosis in KB cell as evidenced by Hoechst-33258 dye staining, flow cytometry (cell cycles), and DNA fragmentation for nuclear condensation and Western blotting for activation of caspases-3, -8, -9, Bax, Bcl-2, cytochrome c, and poly (ADP-ribose) polymerase (PARP) cleavage. In the present study, we found that the essential oil could induce apoptosis in KB cells, as characterized by DNA fragmentation, activation of caspase-3, -8, and -9, and PARP cleavage. The efficacious induction of apoptosis was observed as a dose-dependent. The essential oil-induced apoptotic cell death was accompanied by up-regulation of Bax and down-regulation of Bcl-2. The essential oil also caused the loss of mitochondrial membrane potential and cytochrome c release from mitochondria to cytosol. These findings indicate that mitochondrial pathways might be involved in the essential oil-induced apoptosis and enhance our understanding of the anticancer function of the essential oil in herbal medicine.

• Research in Plant Disease
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• v.12 no.3
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• pp.205-212
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• 2006

Agrobacterium vitis is a causal agent of crown-gall disease on grapevine. Bacterial strains were isolated from crown galls of different grapevine varieties in grapevine farms of Kyungbuk(Kimcheon), Chungbuk(Okcheon), Chungnam(Daejon, Choenan) and Kyeonggi(Suwon, Ansung) areas in Korea from 2002 to 2005. Primer sets, Phe A and VirA, which were derived from pectate lysase gene and virA gene of Ti-plasmid in A. vitis were used to detect A. vitis strains from crown galls. PheA and VirA primers amplified DNA fragments of 0.25 kb and 0.5 kb from fifty-one bacterialstrains. They formed crown galls on grapevine variety, Kyoho, or carrot disks with variable pathgenecity It was confirmed that the biochemical characteristics of 10 bacterial strains that was strong pathogene city on grapevine were mostly in agreement with type culture strains of A. vitis, showing growth in the presence of 2% NaCl, non-production of acid from melezitose and negative response in production of 3-Ketolactose.

• Economic and Environmental Geology
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• v.25 no.1
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• pp.1-16
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• 1992

The Wondong Fe-Pb-Zn deposit is located in endo and exoskarns formed along the contact between the Makkol limestone interbedding pelitic limestone of Ordovician age and quartz porphyry of Cretaceous age. At the Wondong mine, the endoskarn shows a discontinuous zonal arrangement from quartz porphyry to pelitic limestone as follows: unaltered quartz porphyry, weakly altered quartz porphyry zone, intensively altered pinkish quartz porphyry zone, garnet zone, and greyish white and fine-grained clinopyroxene zone developed at pelitic limestone side. In terms of chemical mass balance, intensively altered pinkish quartz porphyry relative to unaltered quartz porphyry shows substantial enrichments in $K_2O$, $Na_2O$, and HREE and depletions in MgO, CaO, total $Fe_2O_3$, and LREE. On the other hand, garnet zone of endoskarn is enriched in CaO, MnO, total $Fe_2O_3$, MgO and depleted in $K_2O$, $Na_2O$. $Al_2O_3$ seems to be determining inert component. Thus the behavior of elements indicates that the mobility of elements depends on the equilibration of hydrothermal fluid and minerals and affects on enrichments by fractionation from and depletions by partition to hydrothermal fluid, respectively. Traversing toward pelitic limestone from a central zone of exoskarn, the exoskarn also shows a zonal arrangement as follows: garnet zone, clinopyroxene zone, and decolored pelitic limestone. The arrangement of mineral assemblages in skarns of the Wondong mine is the result of an increase in CaO and $K_2O$ toward the pelitic limestone. Skarn and ore minerals were formed in the following sequence: early skarn, late skarn and magnetite, pyrite, sphalerite, galena, and molybdenite. On the basis of stabilities of mineral assemblages, physicochemical conditions of the late skarn and magnetite mineralization are estimated to be $350^{\circ}C{\leq}T{\leq}400^{\circ}C$ at 1 Kb, $-23{\leq}log\;fO_2{\leq}-18$, and $0.005{\leq}XCO_2{\leq}0.01$, while those of the early skarn to be $420^{\circ}C{\leq}T{\leq}550^{\circ}C$ at 1 Kb.