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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Korean Journal of Microbiology
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Journal DOI :
The Microbiological Society of Korea
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Volume & Issues
Volume 47, Issue 4 - Dec 2011
Volume 47, Issue 3 - Sep 2011
Volume 47, Issue 2 - Jun 2011
Volume 47, Issue 1 - Mar 2011
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Characterization of a Monosaccharide Transporter mstB Isolated as a Downstream Gene of MsnA in Aspergillus nidulans
Jeon, Mee-Hyang ; Chae, Suhn-Kee ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 281~288
To screen downstream genes of Aspergillus nidulans MsnA showing amino acid sequence similarity to the zinc finger region of Msn2/4 stress response transcription factors in Saccharomyces cerevisiae, differentially expressed genes (DEG) in MsnA overexpressed or msnA null mutant strains compared to wild type have been isolated. The cognate gene IDs were identified by DNA sequencing of the selected DEGs. Among those, DEG6 was known as mstB encoding a putative monosaccharide transporter. Expression level of mstB mRNA was increased in MsnA overproducing strains and MsnA bound directly to the promoter region of mstB in vitro. MstB containing twelve transmembrane domains exhibited 80% of amino acid sequence identities to A. niger MstA a high-affinity monosaccharide transporter. A null mutant of mstB was phenotypically undistinguishable to wild type. On the other hand, forced overexpression of MstB caused the increased formation of sexual structure cleistothecia in 0.1% glucose condition where wild type showed almost no cleistothecia. This result implies that mstB is involved in transport of monosaccharide required for sexual differentiation.
Cold Shock Response and Low Temperature Stable Transcript of DEAD-box RNA Helicase in Bacillus subtilis
Oh, Eun-Ha ; Lee, Sang-Soo ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 289~294
We investigated the cold shock sensitivity of DEAD-box RNA helicase gene deleted strains of in Bacillus subtilis CU1065. To understand cold shock effects, cells were cultivated at
to log phase (
=0.5-0.6) and then temperature was shifted to
. Cold shock slow down the growth rate of wild type and deleted strains of DEAD-box RNA helicase gene (ydbR, yfmL, yqfR, deaD). The growth rate of ydbR deleted strain is 5 times severely reduced compared to that of wild type strain (CU1065). But the growth rate of other three (yfmL, yqfR, deaD) deleted strains is nearly equal to the growth rate of wild type. Compared to
, the amount of ydbR and yqfR mRNA transcripts are increased at the growth temperature of
. On the other hands the mRNA transcripts of yfmL and deaD are not changed at both conditions of
. Upon cold shock treatment ydbR mRNA transcript is clearly increased. After treatment of rifampicin (bacteria transcription inhibitor) the amount of ydbR mRNA was measured. Temperature shift from
and rifampicin treatment showed slowly decay of ydbR mRNA. But at
and rifampicin treatment ydbR mRNA is rapidly reduced. These results showed that cold shock induction of ydbR mRNA resulted from the stability of ydbR mRNA and not from the transcription induction of ydbR. In relation to these results, we found the cold box element of csp (cold shock protein gene) in 5' untranslated region of ydbR gene. Cold shock induction of ydbR is caused by the stability of ydbR mRNA like the stability of csp mRNA.
Identification and Characterization of the Aquaporin Gene aqpA in a Filamentous Fungus Aspergillus nidulans
Oh, Dong-Soon ; Lu, Han-Yan ; Han, Kap-Hoon ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 295~301
Aquaporin is a water channel protein, which is classified as Major Intrinsic Protein (MIP), found in almost all organisms from bacteria to human. To date, more than 200 members of this family were identified. There are two major categories of MIP channels, orthodox aquaporins and aquaglyceroporins, which facilitate the diffusion across biological membranes of water or glycerol and other uncharged compounds, respectively. The full genome sequencing of various fungal species revealed 3 to 5 aquaporins in their genome. Although some functions of aquaporins found in yeast were characterized, however, no functional characteristics were studied so far in filamentous fungi, including Aspergillus sp. In this study, one orthodox aquaporin homolog gene, aqpA, and four aquaglyceroporin homologs, aqpB-E, in a model filamentous fungus Aspergillus nidulans were identified and the function of the aqpA gene was characterized. Knock-out of the aqpA gene didn't show any obvious phenotypic change under the osmotic stress, indicating that the function of the gene does not involved in the osmotic stress response or the function could be redundant. However, the mutant showed antifungal susceptibility resistance phenotype, suggesting that the function of the aqpA gene could be involved in sensing the antifungal substances rather than the osmotic stress response.
Analysis of Amino Acid Residues Involved in Activities of Chitin Deacetylase of Aspergillus nidulans
Kim, Jong-Il ; Song, Da-Hyun ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 302~307
Native chitin deacetylase of Aspergillus nidulans was purified to apparent homogeneity by a combination of phenyl-Sepharose and Q-Sepharose column chromatography. In order to analyze the amino acid residues involved in the enzyme activity, the enzyme was chemically modified with chemical agent, which selectively reacted with the specific amino acid residue on the protein. When the enzyme was chemically modified with diethylpyrocarbonate, which specifically reacted with histidine residues on the protein, the activity was eliminated. The chitin deacetylase, chemically modified with 100
modifier at the residue of arginine or tyrosine, has shown to have decreased activities. It was shown that the modification at aspartic acid or glutamic acid did not affect the enzyme activity to a greater extent, which would not implicate that acid amino residues were directly involved in catalytic reaction and would affect on the global structures of the proteins. This results demonstrated that histidine and tyrosine residues of enzyme would participate in an important function of the chitin deacetylase activity.
Characterization and Antimicrobial Activity of Lactic Acid Bacteria Isolated from Vaginas of Women of Childbearing Age
Ahn, Hye-Ran ; So, Jae-Seong ; Oh, Kye-Heon ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 308~315
The purpose of this work was to examine the antimicrobial activity derived from the lactic acid bacterium, UK-3 isolated from the vaginas of women of childbearing age. Various physiological and biochemical properties of this strain were characterized. Both the BIOLOG system and phylogenetic analysis using 16S rRNA sequencing were utilized for identification, and the strain was designated as Lactobacillus plantarum UK-3, and registered in GenBank as [JK266589]. Growth rate, production of organic acids (e.g., lactic acid and acetic acid), and pH during growth were monitored. The maximum concentrations of lactic acid and acetic acid were approximately 684.11 mM and 174.26 mM, respectively, and pH changed from 7.0 to 3.7 after 72 h of incubation. High performance liquid chromatography was used to confirm lactic acid and acetic acid production. Significant antimicrobial activity of the concentrated supernatant was demonstrated against various Gram-positive (e.g., Staphylococcus aureus, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Neisseria species., Listeria monocytogenes), Gram-negative bacteria (e.g., Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis), and yeast (e.g., Candida albicans) by the plate diffusion method. As a result, the concentrated L. plantarum UK-3 cultures had lower acidity and inhibited the growth of all microorganisms tested, whereas the growth of L. acidophilus was not affected.
-Aminobutyric Acid Production and Glutamate Decarboxylase Activity of Lactobacillus sakei OPK2-59 Isolated from Kimchi
Yu, Jin-Ju ; Oh, Suk-Heung ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 316~322
Lactobacillus sakei OPK2-59 isolated from kimchi was found to have
-aminobutyric acid (GABA) producing ability and glutamate decarboxylase (GAD) activity. When the Lactobacillus sakei OPK2-59 was cultured in MRS broth with 59.13 mM and 177.40 mM monosodium glutamate (MSG), the optimum temperature range and pH for growth were
and pH 6.5, respectively. GABA conversion rates in MRS broth with 59.13 mM and 177.40 mM MSG were 99.58% and 31.00%, respectively at
and 48 h of cultivation. By using the cell free extract of Lactobacillus sakei OPK2-59, MSG was converted to GABA and the conversion rate was 78.51% at
, pH 5. Conversion of MSG to GABA was enhanced by adding salts such as
. These data suggest that the ability of Lactobacillus sakei OPK2-59 to produce GABA results from the activity of GAD in the cells and GABA conversion by the cell extract containing GAD can be enhanced by
Genotype of Group A Rotavirus Isolated in Acute Gastroenteritis Patients and Groundwater in Seoul, Korea
Kim, Eun-Jeung ; Kim, Moo-Sang ; Chae, Young-Zoo ; Cheon, Doo-Sung ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 323~327
Fecal specimens from acute gastroenteritis in Seoul from 2009 to 2010 were collected and then tested for the presence of Group A Rotavirus by ELISA. Among a total of 1,916 samples investigated, 354 samples (18.4%) were positive. The predominant genotypes of positive samples were confirmed as P6G (35%), P8G (28%), P8G (24%), P4G (10%), P8G (3%), respectively. Among a total of 70 ground water samples investigated, 2 samples (2.8%) were positive. The genotypes of positive samples were confirmed as P8G (100%). By this molecular investigation, genotypic distribution associated with rotavirus will be used for control and prevention of rotavirus related diseases.
The Development of Dimerized Chicken Recombinant Single-chain Fv (ScFv) Antibody Using Leucine Zipper Motif
Park, Dong-Woon ; Kim, Eon-Dong ; Kim, Sung-Heon ; Han, Jae-Yong ; Kim, Jin-Kyoo ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 328~334
Leucine zipper motif consists of multiple periodic leucine residues, which forms amphipathic alpha helix. The hydrophobic nature of leucine zipper motif can dimerize proteins which contain this motif. Leucine zipper motif addition at C-terminus of single-chain Fv (ScFv) antibody induces its dimerization. Since the dimeric ScFv antibody contains two antigen binding sites (bivalency) like Y-shaped complete antibody, it could increase avidity. As a result, it could show higher antigen binding activity than monomeric ScFv antibodies. Based on this concept, monomeric chicken 8C3 ScFv antibody previously developed from chicken hybridoma was dimerized by the addition of leucine zipper motif at C-terminus of ScFv antibody. The dimeric 8C3 ScFv antibody specifically reacted with Eimerian sporozoite which causes Avian Coccidiosis. As expected, dimeric 8C3 ScFv antibody showed 3-folds higher antigen binding activity than monomer due to increased avidity. In addition, protien yields of dimer expression were 2-folds higher than monomer.
Biofilm Forming Ability and Production of Curli and Cellulose in Clinical Isolates of Enterobacteriaceae
Choi, Yeh-Wan ; Lee, Hee-Woo ; Kim, Sung-Min ; Lee, Je-Chul ; Lee, Yoo-Chul ; Seol, Sung-Yong ; Cho, Dong-Taek ; Kim, Jung-Min ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 335~341
In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.
The Activation of HCV-specific CD8 T Cells by HCV Peptide Pulsed Huh7.5 Cells
Cho, Hyo-Sun ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 342~347
T cells play a key role in viral infection. However, in patients with chronic hepatitis C virus (HCV) infection, HCV-specific T cells are dysfunctional and impaired in the liver, which is the primary site for HCV replication. There are multiple potential mechanisms for HCV-specific T cell dysfunction including induction of immune inhibitory pathways (program death-1; PD-1, cytotoxic t lymphocyte associated antigen-4; CTLA-4) and immune tolerance induced specific for the liver. However, the interaction between hepatocytes and HCV-specific CD8 T cells has not clearly established. In this study, we confirmed huh (human hepatoma) 7.5 cells expressing HLA (human leukocyte antigen) A2 presented antigen to activate HCV-specific CD8 T cells in HLA A2-restricted manner and expression of PD-L (program death ligand) 1 on huh7.5 cells reduced HCV-specific CD8 T cell activation, suggesting an immune modulatory activity. Loss of HCV-specific tetramer responses following antigenic stimulation correlated with increased caspase-3 activity. In addition, PD-L1 on huh7.5 cells rescued HCV-specific CD8 T cells from apoptosis. Our results suggest that the interaction between PD-L1 and PD-1 can recover the function of HCV-specific CD8 T cells in the liver, which could be applied in therapy of HCV chronic infection.
Stimulatory Effect of Staphylococcal Protein A on Inflammatory Response in Human HaCaT Keratinocytes
Kwon, Hyun-Jin ; Kim, Yeon-Jung ; Jang, Sung-Hee ; Bae, Bo-Kyoung ; Youn, Hwa-Young ; Lee, Hee-Woo ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 348~355
Staphylococcus aureus is a major human pathogen that is associated with various types of local and systemic infection. Staphylococcal protin A (SPA), a highly expressed surface component of S. aureus, may have a role in virulence such as activating inflammation and interfering with immune clearance. We examined the effect of recombinant SPA on inflammatory response in human HaCaT keratinocytes. The recombinant SPA protein was prepared using the pET-28a Vector System in Escherichia coli. The expression of pro-inflammatory related adhesion molecules and cytokines in HaCaT cells incubated for 6, 12, and 24 h with SPA (2
/ml) was analyzed by comparative RT-PCR or ELISA. The expression of E-selectin, ICAM-1, MCP-1, IL-6 and IL-8 was significantly increased in HaCaT from 6 to 24 h after treatment with SPA. SPA showed the effect on the adhesion-promoting ability of U937 monocytes to HaCaT cells. Our data demonstrate that SPA stimulates inflammatory response of HaCaT cells, implicating an important factor for exacerbation of skin inflammation of immunologic disease.
Efficient Remediation of Petroleum Hydrocarbon-Contaminated Soils through Sequential Fenton Oxidation and Biological Treatment Processes
Bae, Jae-Sang ; Kim, Jong-Hyang ; Choi, Jung-Hye ; Ekpeghere, Kalu I. ; Kim, Soo-Gon ; Koh, Sung-Cheol ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 356~363
The accidental releases of total petroleum hydrocarbons (TPH) due to oil spills frequently ended up with soil and ground water pollution. TPH may be degraded through physicochemical and biological processes in the environment but with relatively slow rates. In this study an attempt has been made to develop an integrated chemical and biological treatment technology in order to establish an efficient and environment-friendly restoration technology for the TPH contaminated soils. A Fenton-like reaction was employed as a preceding chemical treatment process and a bioaugmentation process utilizing a diesel fuel degrader consortium was subsequently applied as a biological treatment process. An efficient chemical removal of TPH from soils occurred when the surfactant OP-10S (0.05%) and oxidants (
5%) were used. Bioaugmentation of the degrader consortium into the soil slurry led to an increase in their population density at least two orders of magnitude, indicating a good survival of the degradative populations in the contaminated soils (
CFU/g slurry). TPH removal efficiencies for the Fenton-treated soils increased by at least 57% when the soils were subjected to bioaugmentation of the degradative consortium. However, relatively lower TPH treatment efficiencies (79-83%) have been observed in the soils treated with Fenton and the degraders as opposed to the control (95%) that was left with no treatment. This appeared to be due to the presence of free radicals and other oxidative products generated during the Fenton treatment which might inhibit their degradation activity. The findings in this study will contribute to development of efficient bioremediation treatment technologies for TPH-contaminated soils and sediments in the environment.
Application Potential of Hurdle Technology by Combination of Bacteriocin Produced by Lactobacillus brevis DK25 and Potassium Benzoate
Lim, Sung-Mee ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 364~374
Lactobacillus brevis DK25 isolated from Dongchimi was identified by physiological and biochemical tests and 16S rDNA sequence analysis. Bacteriocin of L. brevis DK25 exhibits inhibitory activity against Enterococcus faecalis and Listeria monocytogenes when using agar well diffusion method. Maximal production of bacteriocin was reached in the beginning of the stationary phase, and inhibitory activity declined after the late stationary phase. This result suggested that bacteriocin was produced in a growth-associated manner. Complete inactivation of bacteriocin activity was observed after treatment with protease, but the activity was stable between pH 4-9 and heat resistant (30 min at
). Bacteriocin showed a concentration-dependent antimicrobial activity against L. monocytogenes KCTC 3569. Moreover, the application experiment showed that combination of bacteriocin (320 AU/ml) with potassium benzoate (0.05%) could significantly reduce the counts of L. monocytogenes KCTC 3569 in mayonnaise during storage at 4 or
for 10 days. Thus, bacteriocin from L. brevis DK25 may be used for hurdle technology by combination with potassium benzoate in order to increase pathogenic bacteria inactivation in food processing and food safety control.
Identification and Characterization of an Endophytic Strain of Streptomyces from Rice Roots (Orysa sativa L.)
Kim, Jae-Heon ; Lee, Jun-Kwan ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 375~380
We isolated an endophytic actionmycete from root tissues of rice plant collected from paddy field near Dankook University, Cheonan, Korea. Surface sterilized roots were laid on the selective agar plates and incubated. The powdery actinomycete colonies appeared on the root surface after four weeks incubation. We isolated a strain JK-5 among them and could determine its taxonomical position as Streptomyces diastaticus subsp. ardesiacus by using 16S ribosomal DNA sequencing. The chemotaxonomical and morphological studies confirmed the taxonomical position of the strain JK-5. The shape of aerial hyphae was flexible and they contained spore chains with more than 30 smooth spherical spores per chain. Cell walls contained LL-diaminopimelic acid. There was no characteristic sugar in whole-cell hydrolysates. The major fatty acids were anteiso-15:0, anteiso-17:0 and iso-16:0. The specific menaquinones, MK-9 (
), MK-9 (
), were detected. The GC content was 72%. Antifungal activities of the strain JK-5 were relatively strong against fungal plant pathogens. The endophytic growth of the strain JK-5 was confirmed by SEM observation of the root and stem of the infected rice plant.
Comparison Between Antimicrobial Susceptibility Test and mecA PCR Method for Reading of Methicillin-Resistant Staphylococcus aureus
Kim, Su-Jung ;
The Korean Journal of Microbiology, volume 47, issue 4, 2011, Pages 381~385
Methicillin-resistant Staphylococcus aureus (MRSA) is one of major pathogen causing hospital infection and several diseases such as purulent infection, bacteremia. The isolation ratio of MRSA is gradually increased up to 80% in the hospital, which makes a limitation for treatment of antibiotics because the isolated MRSA show resistance to methicillin as well as other antibiotics. This study proposes that mecA detecting methods which are not commonly used because of cost in the hospital is a more accurate method than Susceptibility Testing to detect a MRSA. We compared Staphylococcus aureus ATCC 29213 as a negative control and 20 MRSA strains isolated from patients by these two methods. We amplified mecA gene by polymerase chain reaction (PCR) and confirmed the PCR products by sequencing. All of the MRSA showed oxacillin and cefoxitin resistance whereas 85% (16/19) of the strains had mecA wildtype. These results suggest that some of the MRSA are mecA mutants therefore mecA genotyping reinforces the MRSA detection by antibiotic susceptibility test.