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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Microbiology and Biotechnology
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
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Isolation of Uncultivable Anaerobic Thermophiles of the Family Clostridiaceae Requiring Growth-Supporting Factors
Kim, Joong-Jae ; Kim, Hee-Na ; Masui, Ryoji ; Kuramitsu, Seiki ; Seo, Jin-Ho ; Kim, Kwang ; Sung, Moon-Hee ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 611~615
Novel groups of uncultivable anaerobic thermophiles were isolated from compost by enrichment cultivation in medium with a cell-free extract of Geobacillus toebii. The cell-free extract of G. toebii provided the medium with growth-supporting factors (GSF) needed to cultivate the previously uncultured microorganisms. Twenty-nine GSF-requiring candidates were successfully cultivated, and 16 isolated novel bacterial strains were classified into three different groups of uncultivable bacteria. The similarity among these 16 isolates and a phylogenetic analysis using 16S rRNA gene sequences revealed that these GSF-requiring strains represented novel groups within the family Clostridiaceae.
Isolation and Characterization of Marine Bacterial Strain Degrading Fucoidan from Korean Undaria pinnatifida Sporophylls
Kim, Woo-Jung ; Kim, Sung-Min ; Lee, Yoon-Hee ; Kim, Hyun-Guell ; Kim, Hyung-Kwon ; Moon, Seong-Hoon ; Suh, Hyun-Hyo ; Jang, Ki-Hyo ; Park, Yong-Il ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 616~623
In spite of an increasing interest in fucoidans as biologically active compounds, no convenient commercial sources with fucoidanase activity are yet available. A marine bacterial strain that showed confluent growth on a minimal medium containing fucoidan, prepared from Korean Undaria pinnatifida sporophylls, as the sole carbon source was isolated and identified based on a 16S rDNA sequence analysis as a strain of Sphingomonas paucimobilis, and named Sphingomonas paucimobilis PF-1. The strain depolymerized fucoidan into more than 7 distinct low-molecular-mass fucose-containing oligosaccharides, ranging from 305 to 3,749 Da. The enzyme activity was shown to be associated with the whole cell, suggesting the possibility of a surface display of the enzyme. However, a whole-cell enzyme preparation neither released the monomer L-fucose from the fucoidan nor hydrolyzed the chromogenic substrate p-nitrophenyl-
-L-fucoside, indicating that the enzyme may be an endo-acting fucoidanase rather than an
-L-fucosidase. Therefore, this would appear to be the first report on fucoidanolytic activity by a Sphingomonas species and also the first report on the enzymatic degradation of the Korean Undaria pinnatifida sporophyll fucoidan. Moreover, this enzyme activity may be very useful for structural analyses of fucose-containing polysaccharides and the production of bioactive fucooligosaccharides.
Modified T-RFLP Methods for Taxonomic Interpretation of T-RF
Lee, Hyun-Kyung ; Kim, Hye-Ryoung ; Mengoni, Alessio ; Lee, Dong-Hun ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 624~630
Terminal restriction fragment length polymorphism (T-RFLP) is a method that has been frequently used to survey the microbial diversity of environmental samples and to monitor changes in microbial communities. T-RFLP is a highly sensitive and reproducible procedure that combines a PCR with a labeled primer, restriction digestion of the amplified DNA, and separation of the terminal restriction fragment (T-RF). The reliable identification of T-RF requires the information of nucleotide sequences as well as the size of T-RF. However, it is difficult to obtain the information of nucleotide sequences because the T-RFs are fragmented and lack a priming site of 3'-end for efficient cloning and sequence analysis. Here, we improved on the T-RFLP method in order to analyze the nucleotide sequences of the distinct T-RFs. The first method is to selectively amplify the portion of T-RF ligated with specific oligonucleotide adapters. In the second method, the termini of T-RFs were tailed with deoxynucleotides using terminal deoxynucleotidyl transferase (TdT) and amplified by a second round of PCR. The major T-RFs generated from reference strains and from T-RFLP profiles of activated sludge samples were efficiently isolated and identified by using two modified T-RFLP methods. These methods are less time consuming and labor-intensive when compared with other methods. The T-RFLP method using TdT has the advantages of being a simple process and having no limit of restriction enzymes. Our results suggest that these methods could be useful tools for the taxonomic interpretation of T-RFs.
A Novel Approach to Investigating Protein/Protein Interactions and Their Functions by TAP-Tagged Yeast Strains and its Application to Examine Yeast Transcription Machinery
Jung, Jun-Ho ; Ahn, Yeh-Jin ; Kang, Lin-Woo ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 631~638
Tandem affinity purification (TAP) method combined with LC-MS/MS is the most accurate and reliable way to study the interaction of proteins or proteomics in a genome-wide scale. For the first time, we used a TAP-tag as a mutagenic tool to disrupt protein interactions at the specific site. Although lots of commonly used mutational tools exist to study functions of a gene, such as deletional mutations and site-directed mutagenesis, each method has its own demerit. To test the usefulness of a TAP-tag as a mutagenic tool, we applied a TAP-tag to RNA polymerase II, which is the key enzyme of gene expression and is controlled by hundreds of transcription factors even to transcribe a gene. Our experiment is based on the hypothesis that there will be interrupted interactions between Pol II and transcription factors owing to the TAP-tag attached at the C-terminus of each subunit of Pol II, and the abnormality caused by interrupted protein interactions can be observed by measuring a cell-cycle of each yeast strain. From ten different TAP-tagged strains, Rpb7- and Rpb12-TAP-tagged strains show severe defects in growth rate and morphology. Without a heterodimer of Rpb4/Rpb7, only the ten subunits Pol II can conduct transcription normally, and there is no previously known function of Rpb7. The observed defect of the Rpb7-TAP-tagged strain shows that Rpb7 forms a complex with other proteins or compounds and the interruption of the interaction can interfere with the normal cell cycle and morphology of the cell and nucleus. This is a novel attempt to use a TAP-tag as a proteomic tool to study protein interactions.
Construction of Heat-Inducible Expression Vector of Corynebacterium glutamicum and C. ammoniagenes: Fusion of
Operator with Promoters Isolated from C. ammoniagenes
Park, Jong-Uk ; Jo, Jae-Hyung ; Kim, Young-Ji ; Chung, So-Sun ; Lee, Jin-Ho ; Lee, Hyune-Hwan ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 639~647
The heat-inducible expression vectors for Corynebacterium glutamicum and C. ammoniagenes were constructed by using the
and the cryptic promoters, CJ1 and CJ4 that express genes constitutively in C. ammoniagenes. Although the promoters were isolated from C. ammoniagenes, CJ1 and CJ4 were also active in C. glutamicum. To construct vectors, the
promoter was isolated and fused to the CJ1 and CJ4 promoters by recombinant PCR. The resulting artificial promoters, CJ1O and CJ4O, which have one
, and CJ1OX2, which has two successive
, were fused to the green fluorescent protein (GFP) gene followed by subcloning into pCES208. The expression of GFP in the corynebacteria harboring the vectors was regulated successfully by the temperature-sensitive cI857 repressor. Among them, C. ammoniagenes harboring plasmid pCJ1OX2G containing GFP fused to CJ1OX2 showed more GFP than the other ones and the expression was tightly regulated by the repressor. To construct the generally applicable expression vector using the plasmid pCJ1OX2G, the His-tag, enterokinase (EK) moiety, and the MCS were inserted in front of the GFP gene. Using the vector, the expression of pyrR from C. glutamicum was tried by temperature shift-up. The results indicated that the constructed vectors (pCeHEMG) can be successfully used in the expression and regulation of foreign genes in corynebacteria.
Identification of Genes Associated with Fumonisin Biosynthesis in Fusarium verticillioides via Proteomics and Quantitative Real-Time PCR
Choi, Yoon-E. ; Shim, Won-Bo ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 648~657
In this study, we used functional genomic strategies, proteomics and quantitative real-time (qRT)-PCR, to advance our understanding of genes associated with fumonisin production in the fungus Fusarium verticillioides. Earlier studies have demonstrated that deletion of the FCC1 gene, which encodes a C-type cyclin, leads to a drastic reduction in fumonisin production and conidiation in the mutant strain (FT536). The premise of our research was that comparative analysis of F. verticillioides wild-type and FT536 proteomes will reveal putative proteins, and ultimately corresponding genes, that are important for fumonisin biosynthesis. We isolated proteins that were significantly upregulated in either the wild type or FT536 via two-dimensional polyacrylamide gel electrophoresis, and subsequently obtained sequences by mass spectrometry. Homologs of identified proteins, e.g., carboxypeptidase, laccase, and nitrogen metabolite repression protein, are known to have functions involved in fungal secondary metabolism and development. We also identified gene sequences corresponding to the selected proteins and investigated their transcriptional profiles via quantitative real-time (qRT)-PCR in order to identify genes that show concomitant expression patterns during fumonisin biosynthesis. These genes can be selected as targets for functional analysis to further verify their roles in
Effects of pH Shock on the Secretion System in Streptomyces coelicolor A3(2)
Kim, Yoon-Jung ; Song, Jae-Yang ; Hong, Soon-Kwang ; Smith, Colin P. ; Chang, Yong-Keun ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 658~662
Effects of pH shock on the secretion system of S. coelicolor A3(2) have been investigated at a transcriptional level by using DNA microarrays. Actinorhodin secretion was observed to be highly enhanced when an acidic-pH shock was applied to surface grown cultures of S. coelicolor A3(2). In this culture, a gene of actVA-orf1 encoding a putative efflux pump or transporter protein for actinorhodin was strongly upregulated. A major number of efflux pumps for other metabolites and a major number of secretion proteins for protein secretion were also observed to be upregulated with pH shock. The secretion of actinorhodin was observed to be remarkably enhanced in liquid culture as well.
Purification and Characterization of NAD-Dependent n-Butanol Dehydrogenase from Solvent-Tolerant n-Butanol-Degrading Enterobacter sp. VKGH12
Veeranagouda, Y. ; Benndorf, Dirk ; Heipieper, Hermann J. ; Karegoudar, T.B. ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 663~669
The solvent-tolerant bacterium Enterobacter sp. VKGH12 is capable of utilizing n-butanol and contains an
-dependent n-butanol dehydrogenase (BDH). The BDH from n-butanol-grown Enterobacter sp. was purified from a cell-free extract (soluble fraction) to near homogeneity using a 3-step procedure. The BDH was purified 15.37-fold with a recovery of only 10.51, and the molecular mass estimated to be 38 kDa. The apparent Michaelis-Menten constant (
) for the BDH was found to be 4 mM with respect to n-butanol. The BDH also had a broad range of substrate specificity, including primary alcohols, secondary alcohols, and aromatic alcohols, and exhibited an optimal activity at pH 9.0 and
. Among the metal ions studied,
had no effect, whereas
at 1 mM completely inhibited the BDH activity. The BDH activity was not inhibited by PMSF, suggesting that serine is not involved in the catalytic site. The known metal ion chelator EDTA had no effect on the BDH activity. Thus, in addition to its physiological significance, some features of the enzyme, such as its activity at an alkaline pH and broad range of substrate specificity, including primary and secondary alcohols, are attractive for application to the enzymatic conversion of alcohols.
Purification and Characterization of Laccase from Basidiomycete Fomitella fraxinea
Park, Kyung-Mi ; Park, Sang-Shin ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 670~675
A laccase was isolated from the culture filtrate of the basidiomycete Fomitella fraxinea. The enzyme was purified to electrophoretical homogeneity using ammonium sulfate precipitation, anion-exchange chromatography, and gel-filtration chromatography. The enzyme was identified as a monomeric protein with a molecular mass of 47 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel-filtration chromatography, and had an isoelectric point of 3.8. The N-terminal amino acid sequence for the enzyme was ATXSNXKTLAAD, which had a very low similarity to the sequences previously reported for laccases from other basidiomycetes. The optimum pH and temperature for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) were 3.0 and
, respectively. The enzyme also showed a much higher level of specific activity for ABTS and 2,6-dimethoxyphenol (DMP), where the
values of the enzyme for ABTS and 2,6-DMP were 270 and
, respectively, and the
values were 876 and
, respectively. The laccase activity was completely inhibited by L-cysteine, dithiothreitol (DTT), and sodium azide, significantly inhibited by
, and slightly stimulated by
Identification of Chemical Structure and Free Radical Scavenging Activity of Diphlorethohydroxycarmalol Isolated from a Brown Alga, Ishige okamurae
Heo, Soo-Jin ; Kim, Jong-Pyung ; Jung, Won-Kyo ; Lee, Nam-Ho ; Kang, Hahk-Soo ; Jun, Eun-Mi ; Park, Soon-Hye ; Kang, Sung-Myung ; Lee, Young-Jae ; Park, Pyo-Jam ; Jeon, You-Jin ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 676~681
To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative activity of methanolic extracts from the marine brown alga, Ishige okamurae collected off Jeju Island. A potent free radical scavenging activity was detected in the ethyl acetate fraction containing polyphenolic compounds, and the potent antioxidant elucidated as a kind of phlorotannin, diphlorethohydroxycarmalol, by NMR and mass spectroscopic data. The free radical scavenging activities of the diphlorethohydroxycarmalol were investigated in relation to 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals using an electron spin resonance (ESR) system. The diphlorethohydroxycarmalol was found to scavenge DPPH (
) and alkyl (
) radicals more effectively than the commercial antioxidant, ascorbic acid. Therefore, these results present diphlorethohydroxycarmalol as a new phlorotannin with a potent antioxidative activity that could be useful in cosmetics, foods, and pharmaceuticals.
Inhibitory Effect Against Akt by Cyclic Dipeptides Isolated from Bacillus sp.
Hong, Sung-Won ; Moon, Byoung-Ho ; Yong, Yeon-Joong ; Shin, Soon-Young ; Lee, Young-Han ; Lim, Yoong-Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 682~685
Among thirteen strains of the genus Bacillus isolated from Shrimp-jeotkal in our laboratory, a strain BA34 showing good antifungal activity against Phytophthora infestans in a previous experiment was tested for the inhibitory effect against Akt, protein kinase B. Since Akt is known to play an important role in controlling apoptosis, its inhibitors can be used as potential apoptosis-inducing agents in the treatment of cancer. Two active compounds were isolated and their structures were determined. They have similar structures, despite showing different inhibitory effects. In order to elucidate the reasons for these different effects, three-dimensional studies were carried out.
Effects of a Tetramethoxyhydroxyflavone on the Expression of Inflammatory Mediators in LPS-Treated Human Synovial Fibroblast and Macrophage Cells
Yoon, Do-Young ; Cho, Min-Chul ; Kim, Jung-Hee ; Kim, Eun-Jin ; Kang, Jeong-Woo ; Seo, Eun-Hee ; Shim, Jung-Hyun ; Kim, Soo-Hyun ; Lee, Hee-Gu ; Oh, Goo-Taeg ; Hong, Jin-Tae ; Park, Joo-Won ; Kim, Jong-Wan ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 686~694
The inhibitory effects of 5,6,3',5'-tetramethoxy 7,4'-hydroxyflavone (labeled as p7F) were elucidated on the productions of proinflammatory cytokines as well as inflammatory mediators in human synovial fibroblasts and macrophage cells. p7F inhibited IL-1
induced expressions of inflammatory mediators (ICAM-1, COX-2, and iNOS). p7F also inhibited LPS-induced productions of nitric oxide and prostaglandin
in RAW 264.7 cells. In order to investigate whether p7F would inhibit IL-1 signaling, p7F was added to the D10S Th2 cell line (which is responsive to only IL-1
and thus proliferates), revealing that p7F inhibited IL-1
-induced proliferation of D10S Th2 cells in a dose-response manner. A flow cytometric analysis revealed that p7F reduced the intracellular level of free radical oxygen species in RAW 264.7 cells treated with hydrogen peroxide. p7F inhibited IkB degradation and NF-
B activation in macrophage cells treated with LPS, supporting that p7F could inhibit signaling mediated via toll-like receptor. Taken together, p7F has inhibitory effects on LPS-induced productions of inflammatory mediators on human synovial fibroblasts and macrophage cells and thus has the potential to be an anti-inflammatory agent for inhibiting inflammatory responses.
Coproduction of Thermostable Amylase and
-Galactosidase Enzymes by Geobacillus stearothermophilus SAB-40: Application of Plackett-Burman Design to Evaluate Culture Requirements Affecting Enzyme Production
Soliman, Nadia A. ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 695~703
A locally isolated thermophile, Geobacillus sp. SAB-40, producing thermostable extracellular amylase constitutively and an induced intracellular
-galactosidase was characterized and identified based on 16S rRNA sequencing. A phylogenetic analysis then revealed its closeness to Geobacillus stearothermophilus. To evaluate the effect of the culture conditions on the coproduction of both enzymes by G stearothermophilus SAB-40, a Plackett-Burman fractional factorial design was applied to determine the impact of twenty variables. Among the tested variables,
, the incubation time,
, and tryptone were found to be the most significant for encouraging amylase production. Lactose was found to promote
-galactosidase production, whereas starch had a significantly negative effect on lactase production. Based on a statistical analysis, a preoptimized medium attained the maximum production of amylase and
-galactosidase at 23.29 U/ml/ min and 12,958 U/mg biomass, respectively, which was 3-and 2-fold higher than the yield of amylase and lactase obtained with the basal medium, respectively.
Effect of Increased Glutamate Availability on L-Ornithine Production in Corynebacterium glutamicum
Hwang, Joong-Hee ; Hwang, Gui-Hye ; Cho, Jae-Yong ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 704~710
Glutamate availability in the argF-argR-proB
strain of Corynebacterium glutamicum was increased by addition of glutamate to the cell or inactivation of the phosphoenolpyruvate carboxykinase activity and simultaneous overexpression of the pyruvate carboxylase activity to assess its effect on L-ornithine production. When glutamate was increased in an L-ornithine-producing strain, the production of L-ornithine was not changed. This unexpected result indicated that the intracellular concentration and supply of glutamate is not a rate-limiting step for the L-ornithine production in an L-ornithine-producing strain of C. glutamicum. In contrast, overexpression of the L-ornithine biosynthesis genes (argCJBD) resulted in approximately 30% increase of L-ornithine production, from 12.73 to 16.49 mg/g (dry cell weight). These results implied that downstream reactions converting glutamate to L-ornithine, but not the availability of glutamate, is the rate-limiting step for elevating L-ornithine production in the argF-argR-proB
strain of C. glutamicum.
Development of an Enrichment Culture Growing at Low Temperature used for Ensiling Rice Straw
Yang, Hong Yan ; Wang, Xiao Fen ; Gao, Li Juan ; Haruta, Shin ; Ishii, Masaharu ; Igarashi, Yasuo ; Cui, Zong Jun ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 711~717
To speed up the conversion of rice straw into feeds in a low-temperature region, a start culture used for ensiling rice straw at low temperature was selected by continuous enrichment cultivation. During the selection, the microbial source for enrichment was rice straw and soil from two places in Northeast China. Lab-scale rice straw fermentation at
verified, compared with the commercial inoculant, that the selected start culture lowered the pH of the fermented rice straw more rapidly and produced more lactic acid. The results from denatured gradient gel eletrophoresis showed that the selected start culture could colonize into the rice straw fermentation system. To analyze the composition of the culture, a 16S rRNA gene clone library was constructed. Sequencing results showed that the culture mainly consisted of two bacterial species. One (A) belonged to Lactobacillus and another (B) belonged to Leuconostoc. To make clear the roles of composition microbes in the fermented system, quantitative PCR was used. For species A, the DNA mass increased continuously until sixteen days of the fermentation, which occupied 65%. For species B, the DNA mass amounted to 5.5% at six days of the fermentation, which was the maximum relative value during the fermentation. To the authors' best knowledge, this is the first report on ensiling rice straw with a selected starter at low temperature and investigation of the fermented characteristics.
Effect of Oxygen and Shear Stress on Molecular Weight of Hyaluronic Acid Produced by Streptococcus zooepidemicus
Duan, Xu-Jie ; Yang, Li ; Zhang, Xu ; Tan, Wen-Song ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 718~724
Dissolved oxygen (DO) and shear stress have pronounced effects on hyaluronic acid (HA) production, yet various views persist about their effects on the molecular weight of HA. Accordingly, this study investigated the effects of DO and shear stress during HA fermentation. The results showed that both cell growth and HA synthesis were suppressed under anaerobic conditions, and the HA molecular mass was only
. Under aerobic conditions, although the DO level produced no change in the biomass or HA yield, a high DO level favored the HA molecular mass, which reached a maximum value of
at 50% DO. Furthermore, a high shear stress delayed the rate of HA synthesis and decreased the HA molecular weight, yet had no clear effect on the HA yield. Therefore, a high DO concentration and mild shear environment would appear to be essential to enhance the HA molecular weight.
Production of Cyclodextrins in Ultrafiltration Membrane Reactor Containing Cyclodextrin Glycosyltransferase from Bacillus macerans
Son, Young-Jin ; Rha, Chan-Su ; Park, Yong-Cheol ; Shin, So-Yeon ; Lee, Yoon-Seung ; Seo, Jin-Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 725~729
An enzyme reactor installed with ultrafiltration membrane was developed to produce
-cyclodextrins (CDs) from soluble starch by Bacillus macerans cyclodextrin glycosyltransferase (CGTase) tagged with 10 lysines at its C-terminus (CGTKIOase). Ultrafiltration membrane YM10 with 10,000 of molecular cutoff was chosen for membrane modification and CD production. A repeated-batch type of the enzyme reaction with free CGTK10ase resulted in a
-CD yield of 24.0 (
)% and a productivity of 4.68 (
) g/l-h, which were 7 times higher that those for CGTK10ase immobilized on modified YM10 membrane. Addition of 1-nonanol increased CD yields by 30% relative to the control, which might be due to prevention of the reversible hydrolysis of CDs.
Effects of Calcium Ion Concentration on Starch Hydrolysis of Barley
Yuk, Jeong-Bin ; Choi, Seung-Ho ; Lee, Tae-Hee ; Jang, Myoung-Uoon ; Park, Jung-Mi ; Yi, Ah-Rum ; Svensson, Birte ; Kim, Tae-Jip ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 730~734
-amylase genes, amy1 and amy2, were separately cloned into the expression vector of
and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates.
Reusability of Surfactant-coated Candida rugosa Lipase Immobilized in Gelatin Microemulsion-based Organogels for Ethyl Isovalerate Synthesis
Dandavate, Vrushali ; Madamwar, Datta ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 735~741
In our previous study, a surfactant-coated Candida rugosa lipase immobilized in microemulsion-based organogels was exploited for the synthesis of ethyl isovalerate. In the present study, we are focusing on the effective reuse of lipase immobilized in microemulsion-based organogels (MBGs) in terms of retainment of the catalytic activity. As water is one of the co-products in esterification reactions, the removal of water becomes a priority to allow the reaction to work in the forward direction and to prevent back hydrolysis. Taking this fact into consideration, the lipase-containing microemulsion-based organogels were given pretreatment and/or several intermittent treatments with dry reverse micellar solution of AOT in organic solvent during repeated cycles of ester synthesis. The pretreated MBGs with dry reverse micellar solution exhibited lower water content and higher initial rates of esterification in comparison with untreated freshly prepared MBGs. The esterification efficiency of untreated MBGs started decreasing after 5 cycles of reuse and was almost completely lost by the end of the
cycle. In contrast, pretreated MBGs exhibited a gradual decrease in esterification efficiency after 5 cycles and retained about 80% of the initial activity at the end of the
cycle. The intermittent treatment of MBGs after every 3 cycles resulted in enhanced reusability of immobilized lipase for up to 9 cycles without significant loss in esterification activity, after which it resulted in a slow decrease in activity with about 27% lower activity at the end of the
cycle. Furthermore, the treatment conditions such as concentration of AOT in liquid dessicant and time of treatment were optimized with respect to our system. The granulated MBGs proved to be better in terms of initial esterification rates (1.2-fold) as compared with the pelleted MBGs.
Survival of Escherichia coli O157:H7 and Salmonella typhimurium Inoculated on Chicken by Aqueous Chlorine Dioxide Treatment
Hong, Yun-Hee ; Ku, Kyoung-Ju ; Kim, Min-Ki ; Won, Mi-Sun ; Chung, Kyung-Sook ; Song, Kyung-Bin ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 742~745
Inactivation of Escherichia coli O157:H7 and Salmonella typhimurium was evaluated on inoculated chicken by aqueous chlorine dioxide (
) treatment. Chicken samples were inoculated with 6-7 log CFU/g of Escherichia coli O157:H7 and Salmonella typhimurium, respectively. The chicken samples were then treated with 0, 50, and 100 ppm of
solution and stored at
treatment decreased the populations of the pathogenic bacteria on the chicken breast and drumstick. In particular, 100 ppm
treatment on the chicken breast and drumstick reduced Escherichia coli O157:H7 and Salmonella typhimurium by 1.00-1.27 and 1.37-1.44 log CFU/g, respectively. Aqueous
treatment on the growth of the bacteria was continuously in effect during storage, resulting in the decrease of the populations of Escherichia coli O157:H7 and Salmonella typhimurium. These results suggest that aqueous
treatment should be useful in improving the microbial safety of chicken during storage.
Characterization of a Bifunctional HPr Kinase/Phosphorylase from Leuconostoc mesenteroides SY1
Park, Jae-Yong ; Lee, Kang-Wook ; Lee, Ae-Ran ; Jeong, Woo-Ju ; Chun, Ji-Yeon ; Lee, Jong-Hoon ; Kim, Jeong-Hwan ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 746~753
The hprK gene encoding bifunctional HPrK/P (kinase/phosphorylase) was cloned from L. mesenteroides SY1, a strain isolated from kimchi. hprK was transcribed as a monocistronic gene. His-tagged HPrH16A and HPrK/P were produced in E. coli BL21 (DE3) using pET26b(+) and purified. HPrK/P phosphorylation assay with purified proteins showed that the kinase activity of HPrK/P increased at slightly acidic pHs. Divalent cations such as
and glycolytic intermediates such as fructose-1, 6-bisphosphate (FBP) and phosphoenolpyruvate (PEP) increased the kinase activity of HPrK/P, but inorganic phosphate strongly inhibited it. Kinetic studies for the kinase activity of HPrK/P showed that the apparent
values were 0.18 and
for ATP and HPr, respectively. The
value for the phosphorylase activity of HPrK/P was
for P-Ser-HPr (HPr phosphorylated at the serine residue).
Agrobactrium tumefaciens-Mediated Transformation of Monascus ruber
Yang, Yun-Jung ; Lee, In-Hyung ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 754~758
Agrobacterium tumefaciens-mediated transformation (ATMT) was successfully applied to Monascus ruber. The optimum cocultivation time was 84 h with an efficiency of 900 to 1,000 transformants when
spores were used with the same volume of bacteria. The stability of transform ants was over 98% after five generations. When M. ruber was transformed with A. tumefaciens YL-63 containing the green fluorescent protein gene (egfp), the green fluorescent signal was observed throughout hyphae, confirming expression of the gene. This efficient transformation and expression system of M. ruber by ATMT will facilitate the study of this fungus at a molecular genetic level.
Enzymatic Deacetylation of Chitin by Extracellular Chitin Deacetylase from a Newly Screened Mortierella sp. DY-52
Kim, Young-Ju ; Zhao, Yong ; Oh, Kyung-Taek ; Nguyen, Van-Nam ; Park, Ro-Dong ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 759~766
Among more than a hundred colonies of fungi isolated from soil samples, DY-52 has been screened as an extracellular chitin deacetylase (CDA) producer. The isolate was further identified as Mortierella sp., based on the morphological properties and the nucleotide sequence of its 18S rRNA gene. The fungus exhibited maximal growth in yeast peptone glucose (YPD) liquid medium containing 2% of glucose at pH 5.0 and
with 150 rpm. The CDA activity of DY-52 was maximal (20 U/mg) on the 3rd day of culture in the same medium. The CDA was inducible by addition of glucose and chitin. The enzyme contained two isoforms of molecular mass 50 kDa and 59 kDa. This enzyme showed a maximal activity at pH 5.5 and
. In addition, it had a pH stability range of 4.5-8.0 and a temperature stability range of
. The enzyme was enhanced in the presence of
. Among various substrates tested, WSCT-50 (water-soluble chitin, degree of deacetylation 50%), glycol chitin, and crab chitosan (DD 71-88%) were deacetylated. Moreover, the CDA can handle N-acetylglucosamine oligomers
Biodegradation of Endocrine-Disrupting Phthalates by Pleurotus ostreatus
Hwang, Soon-Seok ; Choi, Hyoung-Tae ; Song, Hong-Gyu ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 767~772
Biodegradation of endocrine-disrupting phthalates [diethyl phthalate (DEP), dimethyl phthalate (DMP), butylbenzyl phthalate (BBP)] was investigated with 10 white rot fungi isolated in Korea. When the fungal mycelia were added together with 100 mg/l of phthalate into yeast extract-malt extract-glucose (YMG) medium, Pleurotus ostreatus, Irpex lacteus, Polyporus brumalis, Merulius tremellosus, Trametes versicolor, and T. versicolor MrP1 and MrP13 (transformant of the Mn-repressed peroxidase gene of T. versicolor) could remove almost all of the 3 kinds of phthalates within 12 days of incubation. When the phthalates were added to 5-day pregrown fungal cultures, most fungi except I. lacteus showed the increased removal of the phthalates compared with those of the non-pregrown cultures. In both culture conditions, p. ostreatus showed the highest degradation rates for the 3 phthalates tested. BBP was degraded with the highest rates among the 3 phthalates by all fungal strains. Only 14.9% of 100 mg/I BBP was degraded by the supernatant of P. ostreatus culture in YMG medium in 4 days of incubation, but the washed or homogenized mycelium of P. ostreatus could remove 100% of BBP within 2 days even in distilled water, indicating that the initial BBP biodegradation by P. ostreatus may be attributed to mycelium-associated enzymes rather than extracellular enzymes. The biodegradation rate of BBP by the immobilized cells of P. ostreatus was almost same as that in the suspended culture. The estrogenic activity of 100 mg/I DMP decreased during biodegradation by P. ostreatus.
Isolation and Identification of Phosphate Solubilizing Bacteria from Chinese Cabbage and Their Effect on Growth and Phosphorus Utilization of Plants
Poonguzhali, Selvaraj ; Madhaiyan, Munusamy ; Sa, Tong-Min ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 773~777
Phosphate solubilizing bacteria (PSB) were isolated from the rhizosphere of Chinese cabbage and screened on the basis of their solubilization of inorganic tricalcium phosphate in liquid cultures. Ten strains that had higher solubilization potential were selected, and they also produced indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and siderophores. The strains were identified to be members of Pseudomonas, by 16S rDNA sequence analysis. Seed bacterization with PSB strains increased the root elongation and biomass of Chinese cabbage in seedling culture, although they had no effect on phosphorus uptake of plants. The plant growth promotion by PSB in this study could be due to the production of phytohormones or mechanisms other than phosphate solubilization, since they had no effect on P nutrition.
Bacillus anthracis Spores Influence ATP Synthase Activity in Murine Macrophages
Seo, Gwi-Moon ; Jung, Kyoung-Hwa ; Kim, Seong-Joo ; Kim, Ji-Cheon ; Yoon, Jang-Won ; Oh, Kwang-Keun ; Lee, Jung-Ho ; Chai, Young-Gyu ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 778~783
Anthrax is an infectious disease caused by toxigenic strains of the Gram-positive bacterium Bacillus anthracis. To identify the mitochondrial proteins that are expressed differently in murine macrophages infected with spores of B. anthracis Sterne, proteomic and MALDI-TOF/MS analyses of uninfected and infected macrophages were conducted. As a result, 13 mitochondrial proteins with different expression patterns were discovered in the infected murine macrophages, and some were identified as ATP5b, NIAP-5, ras-related GTP binding protein B isoform CRAa, along with several unnamed proteins. Among these proteins, ATP5b is related to energy production and cytoskeletal rearrangement, whereas NIAP-5 causes apoptosis of host cells due to binding with caspase-9. Therefore, this paper focused on ATP5b, which was found to be down regulated following infection. The downregulated ATP5b also reduced ATP production in the murine macrophages infected with B. anthracis spores. Consequently, this study represents the first mitochondrial proteome analysis of infected macrophages.
Synergistic Interactions Between Chitinase ChiCW and Fungicides Against Plant Fungal Pathogens
Huang, Chien-Jui ; Chen, Chao-Ying ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 784~787
Antifungal activity of ChiCW and synergistic interactions between ChiCW with fungicides were investigated. Conidial germinations of phytopathogenic fungi, Alternaria brassicicola, Botrytis elliptica, and Colletotrichum gloeosporioides, were inhibited by ChiCW but A. longipes was not. In addition, ChiCW showed synergistic effect with fungicides Switch (cyprodinil+fludioxonil) and tebuconazole to inhibit fungal conidial germinations. The level of synergism of ChiCW with tebuconazole was higher than that with Switch. The results indicate that ChiCW may exhibit a higher level of synergism with fungicides that have a primary effect upon membranes.
Human Papillomavirus (HPV) Type Distribution in Korean Women: a Meta-Analysis
Bae, Jeong-Hoon ; Lee, Sung-Jong ; Kim, Chan-Joo ; Hur, Soo-Young ; Park, Yong-Gyu ; Lee, Won-Chul ; Kim, Young-Tak ; Ng, Timothy L. ; Bock, Hans L. ; Park, Jong-Sup ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 788~794
The aim of the present study is to estimate the overall prevalence and type distribution of human papillomavirus (HPV) in Korean women, through literature review and meta-analysis. We searched published data for the period between 1995 and 2007 using the following inclusion criteria; (1) studies using type-specific HPV tests, (2) data from Korean female, (3) with cytologic or pathologic results, (4) having more than 20 cases for each subgroup classified by cytologic results, and (5) HPV detection including types 16, 18, and at least one other type. In total, 18 studies (13,842 cases) published up to April 2007 were identified and selected. Adjusted overall HPV prevalence was 23.9% (95% CI: 23.8-24.1%) in women with normal cytology and 95.8% (95% CI: 95.4-96.2%) in women with cervical cancer. Type 16 was predominant regardless of cervical disease status, and type 58 occupied a significantly larger proportion in high-grade cervical intraepitheliallesions and cervical cancer in Korean women. HPV types 58, 33, and 52 together accounted for about 20% of infections in cervical cancer and high-grade intraepitheliallesions. After introduction of HPV prophylactic vaccines, extended protection, especially against types 58, 33, and 52, will be an important issue for cervical cancer prevention in Korea. The future dominant genotypes will require follow-up epidemiological studies with a large-scale, multicentered, and prospective design.
Development of a Fungal Spore Aerosol Generator: Test with Cladosporium cladosporioides and Penicillium citrinum
Lee, Byung-Uk ; Kim, Young-Joong ; Lee, Chang-Ho ; Yun, Sun-Hwa ; Bae, Gwi-Nam ; Ji, Jun-Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 795~798
As the first step to develop efficient means to control fungal spore bioaerosols, we designed, manufactured, and evaluated a fungal spore aerosol generator. We studied the physical and biological properties of the fungal spore bioaerosols on two common fungal species. The results demonstrated that the fungal spore bioaerosol generator effectively produces fungal spore bioaerosols.
Generation and Characterization of a Stable Full-Length Ecotropic Murine Leukemia Virus Molecular Clone that Produces Novel Phenotypes to Fv1 Restriction
Bae, Eun-Hye ; Park, Sung-Han ; Park, Sang-Min ; Park, Jin-Woo ; Lim, Mi-Suk ; Jung, Yong-Tae ;
Journal of Microbiology and Biotechnology, volume 18, issue 4, 2008, Pages 799~804
Retrovirus tropism can be restricted by host cell factors such as Fv1, TRIM5
, and LvI that inhibit infection by targeting the incoming viral capsid. The Fv1 gene inhibits murine leukemia virus infection in mice, but the precise mechanism of Fv1-mediated restriction is poorly understood. Our previous studies had demonstrated that Fv1-mediated viral tropism can be determined within the capsid protein at position 114. To study the interaction between Fv1 and CA, we introduced amino acid substitution and deletion at this site in the N-tropic AKV capsid gene. The mutated two-LTR proviral DNAs were introduced into SC-1 cells by transfection. After transfection, cell supernatants collected from transfected cells were tested for host range susceptibility. The result indicated that substitution of amino acids did not alter tropism, but the deletion of 114His produced a virus with unusual tropism. The novel phenotype produced here failed to replicate in Fv1-expressing cells. This mutant virus showing such an extreme restriction pattern would be useful for studying the mechanism of Fv1-mediated restriction.