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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 45, Issue 4 - Dec 2009
Volume 45, Issue 3 - Sep 2009
Volume 45, Issue 2 - Jun 2009
Volume 45, Issue 1 - Mar 2009
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Regulation of Corynebacterium ammoniagenes purF and Isolation of purF-Specific Regulatory Proteins
Lee, Seok-Myung ; Kim, Youn-Hee ; Lee, Heung-Shick ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 233~238
The expression of Corynebacterium ammoniagenes purF was analyzed by utilizing a plasmid carrying a cat gene fused to the purF promoter region. Adenine and guanine repressed the expression of the purF gene by 20~30% but hypoxanthine did not exert such repressive effect. The expression purF was maximal at the late log phase and remained constant throughout the stationary phase. Promoter
which was developed in C. glutamicum was also functional in C. ammoniagenes, achieving maximal activity at the late log phase. The promoter outperformed Escherichia coli
promoter by 40~50% level. DNA-affinity purification identified a protein which could bind to the promoter region of the purF gene. The protein showed high similarity to the CRP-family transcriptional regulator encoded by NCgl0120 in C. glutamicum. The size of the screened protein agreed with the expected protein size from the ORF NCgl0120. The corresponding gene in C. ammoniagenes encoded a 42 kDa polypeptide composed of 400 amino acids with expected pI of 4.9. The encoded protein showed 14.1% and 15.8% identity with E. coli and Bacillus subtilis PurR, respectively, suggesting that the isolated protein might be a novel type of regulatory protein involved in the regulation of purine metabolism.
Mutational Analyses of Translation Initiation Factor eIF1A in Saccharomyces cerevisiae
Kwon, Sung-Hun ; Kim, Jun-Ho ; Choi, Bo-Kyung ; Kim, Na-Yeon ; Choi, Do-Hee ; Park, Kyoung-Jun ; Eoh, Jung-Hyun ; Bae, Sung-Ho ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 239~245
Translation initiation factor eIF1A performs essential functions in various initiation steps including 43S preinitiation complex formation in eukaryotes, and contains a highly conserved oligonucleotide-binding (OB) fold. In our previous study, we discovered that eIF1A possesses RNA annealing activity and forms a stable complex with double-stranded RNA. In this study, we initiated site-directed mutations in eIF1A to find the active sites for these biochemical activities and to investigate whether they are essential functions for yeast cell growth. A truncated protein, eIF1A(
T), devoid of both N- and C-terminal domains but containing an intact OB-fold exhibited RNA annealing activity. In contrast, all point mutations in OB-fold domain, except R57D, impaired both RNA annealing and dsRNA binding activities, indicating that the intact OB-fold domain is required for both activities. Viabilities of the mutant yeast cells were not correlated with RNA annealing activity but with the in vivo protein stabilities in the case of R57D and K94D.
Construction of a Fluorescently Labeled Infectious R Peptide-Less Moloney MLV Molecular Clone for Analysis of Syncytium
Lee, Yong-Jin ; Park, Jin-Woo ; Lee, Kyu-Jun ; Bae, Eun-Hye ; Park, Sung-Han ; Lim, Ji-Hyun ; Kim, Sae-Ro-Mi ; Jung, Yong-Tae ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 246~250
Retroviruses enter host cells by membrane fusion between the viral Env proteins on the virus membrane and a virus receptor on the cellular membrane. The envelope protein of the ecotropic Moloney murine leukemia virus is synthesized as a gp85 precursor and is proteolytically cleaved into an extracellular surface unit (SU) and the transmembrane protein (TM). The cytoplasmic tail (16 amino acid; R peptide) of the TM protein is further cleaved by the viral protease during virion maturation. Unlike the wild type Env protrin bearing the R peptide, R peptide-truncated Envelope induces syncytia in susceptible cells. To understand the mechanism of R peptidetruncated Env in syncytium formation, R peptide-truncated Env expressing full-length molecular clone containing EGFP in PRR (proline rich region) of Env was constructed. This molecular clone induced syncytia in transfected NIH3T3 cells, fluorescence was detected in the cytoplasm and at the plasma membrane, while the nuclei did not stain and appeared black by fluorescence microscopy. Interestingly, virions with truncated envelope produced from transfected NIH3T3 cells induced syncytia in NIH3T3 cells, but fluorescence was not detected in the same infected cells. It is believed that cell-free viruses direct the fusion of neighboring cells without infection. Our data suggests that use of EGFP-tagged envelope for monitoring syncytium is a sensitive and convenient method. We also found that virion incorporated the R peptide-truncated Env is able to induce the formation of syncytia by fusion from without.
Detection of Lily symptomless virus, Lily mottle virus, and Cucumber mosaic virus from Lilium Grown in Korea by RT-PCR
Lim, Ji-Hyun ; Bae, Eun-Hye ; Lee, Yong-Jin ; Park, Sung-Han ; Lee, Kyu-Jun ; Kim, Sae-Ro-Mi ; Jung, Yong-Tae ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 251~256
Leaf samples and bulbs showing characteristic symptoms of virus infection were collected from Gang-won, Chung-nam, and Jeju Province of Korea in 2008-2009. Three viruses, Lily symptomless virus (LSV), Lily mottle virus (LMoV), and Cucumber mosaic virus (CMV) were detected by RT-PCR. Virus-infected plant samples were identified; 12 plants with LSV, 20 plants with LMoV, and 1 plant with CMV. Of the twelve LSV infected samples, seven samples were found to be mix-infected with LMoV and LSV. Symptoms of LMoV and LSV mixed infection were fairly severe, like as vein clearing, leaf curling, leaf mottling, leaf mosaic, and yellow streaking. Mixed infection with LMoV and LSV was also found in lily bulbs which have been stored under unfavorable environmental conditions. LMoV predominated in our tests, whereas spread of Lilyvirus X (LVX) was not found. The nucleotide sequences of coat protein (CP) region of seven isolates (4 LMoV, 2 LSV, and 1 CMV) were compared with the corresponding regions of LMoV (AJ564636), LSV (AJ516059) and CMV(AJ296154). The nucleotide sequence homologies between reference viruses and seven isolates were 95-99%. Complete sequencing of seven isolates is necessary to obtain more information on the molecular characteristics of these viruses as well as to increase sensitivity and rapidity of viral detection.
Properties of a Bacillus licheniformis Cellulase Produced by Recombinant Escherichia coli
Park, Jong-Duk ; Kim, Yeon-A ; Yoon, Ki-Hong ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 257~262
Carboxymethyl celluase (cellulase) was purified from cell-free extract of the recombinant Escherichia coli carrying a Bacillus licheniformis WL-12 cellulase gene by DEAE-Sepharose and phenyl-Sepharose column chromatography with specific activity of 163 U/mg protein. The molecular mass of the purified enzyme was estimated to be approximately 49.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme had a pH optimum at 5.5 and a temperature optimum at
. The activity of the enzyme was completely inhibited by SDS (5 mM), and slightly enhanced by
(5 mM). The cellulase was active on CMC, konjac, barely glucan and lichenan, while it did not exhibit activity towards xylan, locust bean gum, and p-nitrophenyl-
-glucopyranoside. The predominant products resulting from the cellulase hydrolysis were cellobiose and cellotriose for cellooligosaccharides including cellotriose, cellotetraose and cellopentaose. The enzyme could hydrolyze cellooligosaccharides larger than cellobiose.
Increased Production of Amino Acids in an Escherichia coli rpoS Mutant
Jung, Il-Lae ; Kim, In-Gyu ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 263~267
An RpoS factor is a transcriptional regulator which participates in numerous biological processes. In this work, we investigated the transcriptional regulation of proBA and proC composing proline biosynthetic pathway in Escherichia coli. While the proBA and proC genes were greatly induced in an exponential growth phase, they were dramatically repressed in a stationary growth phase in the wild type E. coli. Unlike the wild type E. coli, the proBA and proC genes were not repressed even in the stationary growth phase in its isogenic rpoS mutant. These results suggest that the RpoS factor acts as a transcriptional repressor of proBA and proC genes. The production of threonine, methionine, lysine, and arginine in the rpoS mutant were also increased by more than two times compared to its parental wild type, suggesting that the mutant is able to be used as an useful host strain for the amino acid overproduction.
A Mutant Arthrospira platensis M20CJK3 Showing Enhanced Growth Rate and Floatation Activity
Yoo, Chan ; Kim, Choong-Jae ; Choi, Gang-Guk ; Ahn, Chi-Yong ; Choi, Jong-Soon ; Oh, Hee-Mock ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 268~274
A photosynthetic cyanobacterium Arthrospira platensis, well known for health food supplement, was studied as a target species for atmospheric
removal as well as biomass production. Although the biomass of A. platensis was massively produced in many countries, the recovery cost of its biomass is still high. The purpose of this study was to develop the A. platensis mutant strains which have enhanced growth rate and floatation activity to reduce the recovery cost. A. platensis KCTC AG20590 was treated with 0.24% ethyl methanesulfonate (EMS) for 20 min at room temperature. The mutant strain A. platensis M20CJK3 was finally selected by its morphological and physiological features. The morphology of the mutant A. platensis M20CJK3 was changed from loose-coiled form to tight-coiled form showing short pitch. The growth and
uptake rate of A. platensis M20CJK3 were improved about 15% and 17% compared with A. platensis KCTC AG20590, respectively. The floatation activity of A. platensis M20CJK3 was enhanced in 2-fold compared with that of A. platensis KCTC AG20590. Soluble proteins extracted from two strains were analyzed by two dimensional electrophoresis (2-DE) and MALDI-TOF MS/MS. Among 15 protein spots induced in 2-DE analysis, two spots were the proteins related to photosynthesis and electron transfer system of the other cyanobacteria. As a consequence, it seems that the tight-coiled mutant A. platensis M20CJK3 has an advantage of high growth rate and floatation activity which are beneficial for the mass cultivation and recovery.
Production and Structural Analysis of Cellulose by Acetobacter sp. V6 Using Static Culture
Kim, Jeong-Do ; Jung, Ho-Il ; Jeong, Jin-Ha ; Park, Ki-Hyun ; Jeon, Young-Dong ; Hwang, Dae-Youn ; Lee, Chung-Yeol ; Son, Hong-Joo ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 275~280
The optimal medium compositions for the production of bacterial cellulose (BC) by a Acetobacter sp. V6, which was isolated from the traditionally fermented vinegar in Korea, were investigated in static cultures. The optimum medium compositions for BC production were 3% glucose, 3% soytone, 0.8%
, and 0.4% ethanol, respectively. Adding
had not shown the increase in BC production. Under the optimum medium compositions, the highest BC production was 44.67 g/
in 8 days and the thickness of BC pellicle was about 1 cm. Structural properties of BC produced in the optimal medium were studied using Fourier-transform infrared spectroscopy and X-ray diffractometer. BC from the optimal medium was found to be of cellulose type I, the same as typical native cellulose. No difference in the compositions between bacterial and plant celluloses, but BC showed unique micro-network structure and high crystallinity (82%).
Evaluation of Liquid Culture System in Sputum Culture and Drug Susceptibility of Mycobacterium tuberculosis
Kim, Jin-Sook ; Kim, Seung-Cheol ; Jeon, Bo-Young ; Park, Seung-Kyu ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 281~285
In this study, we compared the BacT/Alert liquid culture system with Ogawa and
-Jensen (L-J) media for sputum culture and drug susceptibility test (DST) of Mycobacterium tuberculosis. Rapid liquid culture systems have been widely employed both for primary cultures of M. tuberculosis from clinical specimens and for drug susceptibility test because of its greater sensitivity and faster turn-around time than the conventional egg-based culture methods (Ogawa,
-Jensen media). Sputum specimens were decontaminated with N-acetyl-L-cysteine (NALC)-4% NaOH and inoculated into the BacT/Alert culture bottles and Ogawa media. 95 from among 135 sputa were smear-positive, 97 (71.9%) were culture-positive by the BacT/Alert culture system, while 89 (65.9%) were positive by Ogawa media. The mean time to culture-positive by the BacT/Alert process system was about 11.3 days, which was significantly shorter than that by Ogawa media (22.4 days). Of 32 M. tuberculosis cultures examined for drug sensitivity, the concordant rate between the two methods (BacT/ Alert liquid culture system,
-Jensen media) ranged from 87.5% for isoniazid and 90.6% for rifampicin.
Deterimination of an Optimal Time Point for Analyzing Transcriptional Activity and Analysis of Transcripts of Avian Influenza Virus H9N2 in Cultured Cell
Na, Gi-Youn ; Lee, Young-Min ; Byun, Sung-June ; Jeon, Ik-Soo ; Park, Jong-Hyeon ; Cho, In-Soo ; Joo, Yi-Seok ; Lee, Yun-Jung ; Kwon, Jun-Hun ; Koo, Yong-Bum ;
The Korean Journal of Microbiology, volume 45, issue 3, 2009, Pages 286~290
The transcription of mRNA of avian influenza virus is regulated temporally during infection. Therefore, the measurement of transcript level in host cells should be performed before viral release from host cells because errors can occur in the analysis of the transcript levels if the viruses released from the infected cells re-infect cells. In this study, the timing of viral release was determined by measuring the level of viral RNA from viruses released from H9N2-infected chicken fibroblast cell line UMNSAH/DF-1 by semi-quantitative RT-PCR. The viral genomic RNA was isolated together with mouse total RNA which was added to the collected medium as carrier to monitor the viral RNA recovery and to use its GAPDH as an internal control for normalizing reverse transcription reaction as well as PCR reaction. It was found that viral release of H9N2 in the chicken fibroblast cell line UMNSAH/DF-1 took between 16 and 20 h after infection. We measured all 8 viral mRNA levels. Of the 8 transcripts, 7 species of viral mRNAs (each encoding HA, NA, PB1, PB2, NP, M, NS, respectively) except PA mRNA showed robust amplification, indicating these mRNA can be used as targets for amplification to measure transcript levels. These results altogether suggest that the method in this study can be used for screening antiviral materials against viral RNA polymerase as a therapeutic target.