• Ocean and Polar Research
• /
• v.26 no.4
• /
• pp.595-606
• /
• 2004

Hydrographic survey in the Korea Strait has long history that has begun in August 1917 at the Busan - Tsushima cross section, still continues to date. However, chemical properties of bottom cold water found exclusively in the western channel of the Korea Strait during summer did not receive much scientific attention. The aim of the study is to decipher the enigmatic origin of the Korea Strait Bottom Cold Water (KSBCW) in terms of chemical properties. The physicochemical properties of the KSBCW are extracted from the CREAHS II hydrographic data. OMP method was applied to analyze origin of the KSBCW quantitatively. The KSBCW is well defined by low temperature below $10^{\circ}C$. The cold waters exhibited the local presence near the coast at about 120m depth with a thickness of 20m to 30m. The cold water was characterized by relatively cold, saline and higher chemical concentrations than adjacent waters. The KSBCW seems to have different origin kom that of the coastal upwelled waters at the Ulgi-Gampo because it is saline, denser and contains considerably less dissolved oxygen than upwelled waters. The physicochemical properties are reported to have noticeable annual variations which suggest the complex origin of the KSBCW. OMP analysis show that the KSBCW is a mixture of three water types; TMW (24%), ESIW (36%) and ESPW (40%). Relationship between the KSBCW and the east Sea circulation is traced by mapping the water masses that have similar T, S and DO of KSBCW. The result showed that the KSBCW is most possibly an extension of southward flowing coastal intermediate waters. Front these results, we expect that the monitoring KSBCW will provide us valuable information about the East Sea circulation.

• Korean Journal of Veterinary Service
• /
• v.32 no.4
• /
• pp.335-341
• /
• 2009

Canine brucellosis produce abortions and infertility in dogs and is currently diagnosed by serological methods such as rapid slide agglutination test with 2-mercaptoethanol (2-ME RSAT) and immunochromatographic assay (ICA). Bacterial isolation is considered gold standard for Brucella diagnosis and the polymerase chain reaction (PCR) is an alternative method to bacterial isolation. A total of 36 whole blood samples were collected from dogs reared in area of Chuncheon and were subjected to serology (2-ME RSAT and ICA for B. canis, Rose Bengal test and C-ELISA for B. abortus), blood culture and 3 types of PCRs (BSCP31, 16s rRNA, and OMP-2). All blood samples were negative by serology and blood cultures. The BCSP31 and the OMP-2 PCR detected 5 samples were positive whereas the 16S rRNA PCR detected all samples were negative as serological methods and blood culture did. From the results observed in the present study, we conclude that 16S rRNA PCR could be used for direct PCR for canine blood samples.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.6
• /
• pp.553-559
• /
• 1998

cDNA of human thrombopoietin (hTPO) amplified by polymerase chain reaction from a cDNA library of human fetal liver was cloned. EPO-like domains ($hTPO_{153} \;or\; hTPO_{l63})\; of\; hTPO(hTPO_{332}$) were expressed in Escherichin coli using several kinds of expression systems, such as ompA secretion, thioredoxin fusion, and the $P_L$ and T7 expression systems. To obtain $hTPO_{153}$ in soluble form, $hTPO_{153}$ cDNA was fused in-frame behind the gene encoding ompA signal sequence and thioredoxin protein. When fused with either of the genes, $hTPO_{153}$ was not expressed to the detectable level. However, a high level expression of the EPO-like domain of hTPO was obtained using the PL and T7 expression system. $hTPO_{153} \;or\; hTPO_{l63} cDNA were subcloned into the pLex and pET-28a(＋) vectors under the control of the inducible$ P_L\;T_7$ promoter, respectively. Proteins expressed using pl.ex vector and pET-28a(＋) detected in insoluble forms with an expression level of about 14% and 9% of total cellular proteins, respectively, and the level of expression was rapidly diminished in 2 h after the maximum level of expression was reached.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.5
• /
• pp.299-304
• /
• 1997

Expression in the periplasm of Escherichia coli of cloned heavy and light chain cDNAs for Fab fragment of a murine monoclonal antibody MabB9 (${\gamma}2b$, K), specific for human plasma apolipoprotein B-100 of LDL, was studied. For the purpose, a vector for two-cistronic expression of the heavy chain cDNA, at the 5' terminus, and light chain cDNA, at the 3' terminus, was constructed using the signal sequences, pelB (for heavy chain) and ompA (for light chain) in a pET vector system. The constructed vector was transformed into E. coli BL21(DE3). The expressed heavy chain (25 kDa) and light chain (23 kDa) of the antibody molecule were detected in total cell extracts as well as in the periplasmic extracts of E. coli.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.3
• /
• pp.368-377
• /
• 2020

Enterotoxigenic Bacteroides fragilis (ETBF) is the main pathogen causing severe inflammatory diseases and colorectal cancer. Its biofilm plays a key role in the development of colorectal cancer. The objective of this study was to determine the antagonistic effects of cell-free supernatants (CFS) derived from Clostridium butyricum against the growth and biofilm of ETBF. Our data showed that C. butyricum CFS inhibited the growth of B. fragilis in planktonic culture. In addition, C. butyricum CFS exhibited an antibiofilm effect by inhibiting biofilm development, disassembling preformed biofilms and reducing the metabolic activity of cells in biofilms. Using confocal laser scanning microscopy, we found that C. butyricum CFS significantly suppressed the proteins and extracellular nucleic acids among the basic biofilm components. Furthermore, C. butyricum CFS significantly downregulated the expression of virulence- and efflux pump-related genes including ompA and bmeB3 in B. fragilis. Our findings suggest that C. butyricum can be used as biotherapeutic agent by inhibiting the growth and biofilm of ETBF.

• Journal of Microbiology
• /
• v.40 no.1
• /
• pp.63-69
• /
• 2002

A total of twenty-five norfloxacin resistant Escherichia coli were isolated from Joongrang-chun stream, a branch of the Han River in Seoul, Korea from May to July in 2000 and their norfloxacin resistance mechanism was characterized for target site mutation, permeability, and efflux pump. Fourteen iso- lates contained the same three mutations, Ser83→Leu and Asp87→Asn in GyrA and Ser90→ lle in ParC. Six isolates had Ser83→Leu and Asp87→Tyr in GyrA and Ser87→lle in ParC while one isolate had Ser83→Leu and Va1103→Ala in GyrA and Ser80→lle in ParC. Two isolates had mutation(s) in GyrA without any mutation in ParC. Two isolates had Ser80→Arg in ParC instead of the commonly found Ser80→lle. Every norfloxacin resistant isolate had an efflux system but the correlation between the efflux activity and MIC was not observed. The amount of OmpF for norfloxacin permeability decreased in resistant isolates compared to the susceptible strains. When amplified polymorphic DNA (RAPD) and pulse field gel electrophoresis (PFGE) were performed, these isolates showed no similarity to each other or clinical isolates.

• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.135-141
• /
• 2004

Human granulocyte colony-stimulating factor (hG-CSF) is a hematopoiesis agent that principally affects the differentiation of neutrophils in the bone marrow. At present, recombinant hG-CSF is used successfully in the treatment of chemotheraphy-induced neutropenia and its indication has been expanded to bone marrow transplantation and aplastic anemia. In this study, we have constructed rhG-CSF secretion plasmid pYRC1 in which OmpA signal sequence/hG-CSF gene was expressed under the control of the T7 promoter. rhG-CSF produced in E. coli BL21 (pYRC1) grown at $37{\circ}C$ was found in aggregates. However, 15% of the periplasmic protein was soluble rhG-CSF when the E. coli BL21 (pYRC1) was cultured at $25^{\circ}C$ for 7 h in the modified MBL medium containing 10 g/$\ell$ glucose with 10 $\mu$M IPTG induction. The production of soluble rhG-CSF in E. coli BL21 (pYRC1) using fed batch culture was also studied. In the fed batch culture system, the final yield of rhG-CSF produced from E. coli BL21 (pYRC1) was increased from 4.4 mg/$\ell$to 24 mg/$\ell$by controlling the specific growth rate from $0.43 h^{-1}$ to $0.14 h^{-1}$, and optimizing the time of induction.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.2
• /
• pp.302-311
• /
• 2004

Comamonas testosteroni (formerly Pseudomonas sp.) NCIMB 10643 can grow on biphenyl and alkylbenzenes $(C_2-C_7)$ via 3-substituted catechols. Thus, to identify the genes encoding the degradation, transposon-mutagenesis was carried out using pAG408, a promoter-probe mini-transposon with a green fluorescent protein (GFP), as a reporter. A mutant, NT-1, which was unable to grow on alkylbenzenes and biphenyl, accumulated catechols and exhibited an enhanced expression of GFP upon exposure to these substrates, indicating that the gfp had been inserted in a gene encoding a broad substrate range catechol 2,3-dioxygenase. The genes (2,826 bp) flanking the gfp cloned from an SphI-digested fragment contained three complete open reading frames that were designated bphCDorfl. The deduced amino acid sequences of bphCDorfl were identical to 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC), 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase (BphD), and OrfI, respectively, that are all involved in the degradation of biphenyl/4-chlorobiphenyl (bph) by Ralstonia oxalatica A5. The deduced amino acid sequence of the orfl revealed a similarity to those of outer membrane proteins belonging to the OmpW family. The introduction of the bphCDorfl genes enabled the NT-l mutant to grow on aromatic hydrocarbons. In addition, PCR analysis indicated that the DNA sequence and gene organization of the bph operon were closely related to those in the bph operon from Tn4371 identified in strain A5. Furthermore, strain A5 was also able to grow on a similar set of alkylbenzenes as strain NCIMB 10643, demonstrating that, among the identified aromatic hydrocarbon degradation pathways, the bph degradation pathway related to Tn4371 was the most versatile in catabolizing a variety of aromatic hydrocarbons of mono- and bicyclic benzenes.

• Journal of Life Science
• /
• v.15 no.4 s.71
• /
• pp.553-560
• /
• 2005

The stf (Salmonella typhimurium fimbriae) operon consisting of stfA(CDEFG assumes to encode putative fimbriae. The complete stf operon is existed in S. typhimurium and S. choleraesuis, whereas it is absent in S. typhi. Analyses of the amino acid residues between major subunit StfA of the Stf fimbriae and those of known other fimbriaes suggested that Stf belongs to class I type fimbriae. Through comparison of StfD chaperone with the other fimbrial chaperones, and of C-terminus in subunits of Stf fimbriae, it belongs to FGS (with a short Fl-G1 loop) subfamily. In order to investigate the expression of stf operon, we have constructed a Salmonella strain containing a chromosomal stfA::lacZYA transcriptional fusion, resulting in S. typhimurium $_X8532$. The strain $_X8532$ lacked the expression of \beta-galactosidase$ under normal culture conditions. However, with longer incubation time of the S. typhimurium $_X8532$, we have isolated 21 individual strains exhibiting $Lac^+$ phenotype. $Lac^+$ phenotype was appeared as approximately 0.03 frequency per generation. All isolates expressed lacZ constitutively in the various environmental conditions. Various global regulatory proteins including RpoS, OmpR, and CpxR were not involved in the regulation of the stf operon. A S. typhimurium $_X8661$ mutant lacking stfAC function attenuated 6.7 folds more than that of wild type $_X3761$ in the mouse virulence test, suggesting in the somehow involved in the Salmonella pathogenesis.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.6
• /
• pp.1106-1111
• /
• 2017

Escherichia coli was engineered to sense methanol by employing a chimeric two-component system (TCS) strategy. A chimeric MxaY/EnvZ (MxaYZ) TCS was constructed by fusing the Paracoccus denitrificans MxaY with the E. coli EnvZ. Real-time quantitative PCR analysis and GFP-based fluorescence analysis showed maximum transcription of ompC and the fluorescence at 0.01% of methanol, respectively. These results suggested that E. coli was successfully engineered to sense methanol by the introduction of chimeric MxaYZ. By using this strategy, various chimeric TCS-based bacterial biosensors can be constructed and used for the development of biochemical-producing recombinant microorganisms.