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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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The Korean Society for Applied Microbiology and Biotechnology
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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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Molecular Characterization of Burkholderia Strains Isolated from Rice Cultivars (Oryza sativa L.) for Species Identification and Phylogenetic Grouping
Madhaiyan, Munusamy ; Poonguzhali, Selvaraj ; Kwon, Soon-Wo ; Song, Myung-Hee ; Sa, Tong-Min ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1005~1010
The genus Burkholderia consists of extremely versatile bacteria that occupy diverse niches and are commonly encountered in the rhizosphere of crop plants. In this study, we characterized three plant growth promoting strains assigned as Burkholderia sp. using biochemical and molecular characterization. The Burkholderia spp. strains CBMB40, CBPB-HIM, and CBPB-HOD were characterized using biochemical tests, BIOLOG carbon substrate utilization, fatty acid methyl ester analysis, analysis of recA gene sequences, and DNA-DNA hybridization. The results from these studies indicated that the strains CBMB40, CBPB-HIM, and CBPB-HOD can be assigned under Burkholderia vietnamiensis, Burkholderia ubonensis, and Burkholderia pyrrocinia, respectively.
Sphingopyxis panaciterrae sp. nov., Isolated from Soil of Ginseng Field
Lee, Hae-Won ; Ten, Irina L. ; Jung, Hae-Min ; Liu, Qing-Mei ; Im, Wan-Taek ; Lee, Sung-Taik ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1011~1015
A Gram-negative, strictly aerobic, motile bacterial strain, designated Gsoil
, was isolated from a soil sample taken from a ginseng field in Pocheon Province (South Korea). The isolate contained Q-10 as the predominant lipoquinone, plus
and summed feature 4 (
2-OH) as the major fatty acids. The G+C content of the genomic DNA was 68.1 mol%, and the major polar lipids consisted of sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, and phosphatidylethanolamine. A comparative 16S rRNA gene sequence analysis showed that strain Gsoil
was most closely related to Sphingopyxis chilensis (98.7%), Sphingopyxis alaskensis (98.2%), Sphingopyxis witflariensis (98.2%), Sphingopyxis taejonensis (98.0%), and Sphingopyxis macrogoltabida (97.6%). However, the DNA-DNA relatedness between strain Gsoil
and its phylogenetically closest neighbors was less than 22%. Thus, on the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil
should be classified as representing a novel species in the genus Sphingopyxis, for which the name Sphingopyxis panaciterrae sp. nov. is proposed. The type strain is Gsoil
Diversity of the Lichenized Fungi in King George Island, Antarctica, Revealed by Phylogenetic Analysis of Partial Large Subunit rDNA Sequences
Lee, Jin-Sung ; Lee, Hong-Kum ; Hur, Jae-Seoun ; Andreev, Mikhail ; Hong, Soon-Gyu ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1016~1023
Lichens are predominant and important components of flora in the terrestrial ecosystem of Antarctica. However, relatively few researches on the phylogenetic position of Antarctic lichen-forming fungi have been accomplished. In this study, partial sequences of nuclear large subunit rDNAs from 50 Antarctic specimens were obtained and the phylogeny was reconstructed. Antarctic lichen species were distributed in 4 orders, including the monophyletic order Agyrales, paraphyletic orders Pertusariales and Teloschistales, and polyphyletic order Lecanorales. Species diversity was highest in the order Lecanorales, followed by Teloschistales and Pertusariales. Based on the phylogeny and sequence similarity analyses, it is proposed that the taxonomy of Stereocaulon alpinum, Physcia caesia, Usnea aurantiacoatra, and Cladonia species should be revised by careful examination of their phenotypic and molecular characteristics. Six species known to be endemic to Antarctica, Catillaria corymbosa, Himantormia lugubris, Leptogium puberulum, Pertusaria pertusa, Rhizoplaca aspidophora, and Umbilicaria antarctica, formed unique lineages, implying independent origins in the Antarctic area.
Molecular Analysis of the Salmonella Typhimurium tdc Operon Regulation
Kim, Min-Jeong ; Lim, Sang-Yong ; Ryu, Sang-Ryeol ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1024~1032
Efficient expression of the Salmonella Typhimurium tdc ABCDEG operon involved in the degradation of L-serine and L-threonine requires TdcA, the transcriptional activator of the tdc operon. We found that the tdcA gene was transiently activated when the bacterial growth condition was changed from aerobic to anaerobic, but this was not observed if Salmonella was grown anaerobically from the beginning of the culture. Expression kinetics of six tdc genes after anaerobic shock demonstrated by a real-time PCR assay showed that the tdc CDEG genes were not induced in the tdcA mutant but tdcB maintained its inducibility by anaerobic shock even in the absence of tdcA, suggesting that an additional unknown transcriptional regulation may be working for the tdcB expression. We also investigated the effects of nucleoid-associated proteins by primer extension analysis and found that H-NS repressed tdcA under anaerobic shock conditions, and fis mutation delayed the peak expression time of the tdc operon. DNA microarray analysis of genes regulated by TdcA revealed that the genes involved in N-acetylmannosamine, maltose, and propanediol utilization were significantly induced in a tdcA mutant. These findings suggest that Tdc enzymes may playa pivotal role in energy metabolism under a sudden change of oxygen tension.
A Novel Negative Regulatory Factor for Nematicidal Cry Protein Gene Expression in Bacillus thuringiensis
Yu, Ziquan ; Bai, Peisheng ; Ye, Weixing ; Zhang, Fengjuan ; Ruan, Lifang ; Yu, Ziniu ; Sun, Ming ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1033~1039
A 3-kb HindIII fragment bearing the cry6Aa2 gene and the adjacent and intergenic regions was cloned from Bacillus thuringiensis strain YBT-1518. Two open reading frames (ORFs), namely, orf1 (termed cry6Aa2) and orf2 that were separated by an inverted-repeat sequence were identified. orf1 encoded a 54-kDa protein that exhibited high toxicity to the plant-parasitic nematode Meloidogyne hapla. The orf2 expression product was not detected by SDS-PAGE, but its mRNA was detected by RT-PCR. The orf2 coexpressed with orf1 at a high level in the absence of the inverted-repeat sequence, whereas, the expression level of otfl was decreased. When orf2 was mutated, the level of orf1 expression was enhanced obviously. In conclusion, the inverted-repeat sequence disturbs orf2 expression, and the orf2 downregulates orf1 expression. This is an example of novel negative regulation in B. thuringiensis and a potential method for enhancing the expression level of cry genes.
Characterization of a Chromosomal Nickel Resistance Determinant from Klebsiella oxytoca CCUG 15788
Park, Jae-Sun ; Lee, Sung-Jae ; Rhie, Ho-Gun ; Lee, Ho-Sa ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1040~1043
Klebsiella oxytoca CCUG 15788 is resistant to
at a concentration of 10 mM and grows in an inducible manner when exposed to lower concentrations of
. The complete genomic sequence of a 4.2-kb HindIII-digested fragment of this strain was determined from genomic DNA. It was shown to contain four nickel resistance genes (nirA, nirB, nirC, and nirD) encoding transporter and transmembrane proteins for nickel resistance. When the plasmid pKOHI4, encoding nirABCD, was transformed into Escherichia coli JM109, the cells were able to grow in Tris-buffered mineral medium containing 3 mM nickel. TnphoA'-1 insertion mutants in the four nickel genes nirA, nirB, nirC, and nirD showed nickel sensitivity. The nir genes were heterogeneously expressed in E. coli, suggesting functional roles of these genes in nickel resistance.
Functional Nucleotides of U5 LTR Determining Substrate Specificity of Prototype Foamy Virus Integrase
Kang, Seung-Yi ; Ahn, Dog-Gn ; Lee, Chan ; Lee, Yong-Sup ; Shin, Cha-Gyun ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1044~1049
In order to study functional nucleotides in prototype foamy virus (PFV) DNA on specific recognition by PFV integrase (IN), we designed chimeric U5 long terminal repeat (LTR) DNA substrates by exchanging comparative sequences between human immunodeficiency virus type-1 (HIV-1) and PFV U5 LTRs, and investigated the 3'-end processing reactivity using HIV-1 and PFV INs, respectively. HIV-1 IN recognized the nucleotides present in the fifth and sixth positions at the 3'-end of the substrates more specifically than any other nucleotides in the viral DNA. However, PFV IN recognized the eighth and ninth nucleotides as distinctively as the fifth and sixth nucleotides in the reactions. In addition, none of the nucleotides present in the twelfth, sixteenth, seventeenth, eighteenth, nineteenth, and twentieth positions were not differentially recognized by HIV-1 and PFV INs, respectively. Therefore, our results suggest that the functional nucleotides that are specifically recognized by its own IN in the PFV U5 LTR are different from those in the HIV-1 U5 LTR in aspects of the positions and nucleotide sequences. Furthermore, it is proposed that the functional nucleotides related to the specific recognition by retroviral INs are present inside ten nucleotides from the 3'-end of the U5 LTR.
Functional, Genetic, and Bioinformatic Characterization of Dextransucrase (DSRBCB4) Gene in Leuconostoc mesenteroides B-1299CB4
Kang, Hee-Kyoung ; Kim, Young-Min ; Kim, Do-Man ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1050~1058
A gene encoding a dextransucrase (dsrBCB4) that synthesizes only
-1,6-linked dextran was cloned from Leuconostoc mesenteroides B-1299CB4. The coding region consisted of an open reading frame (ORF) of 4,395 bp that coded a 1,465-amino-acids protein with a molecular mass of 163,581 Da. The expressed recombinant DSRBCB4 (rDSRBCB4) synthesized oligosaccharides in the presence of maltose or isomaltose as an acceptor, plus the products included
-1,6-linked glucosyl residues in addition to the maltosyl or isomaltosyl residue. Alignments of the amino acid sequence of DSRBCB4 with glucansucrases from Streptococcus and Leuconostoc identified conserved amino acid residues in the catalytic core that are critical for enzyme activity. The mutants D530N, E568Q, and D641N displayed a 98- to 10,000-fold reduction of total enzyme activity.
Genome-Wide Identification of Haploinsufficiency in Fission Yeast
Baek, Seung-Tae ; Han, Sang-Jo ; Nam, Mi-Young ; Kim, Young-Dae ; Kim, Li-La ; Lee, Hyun-Jee ; Heo, Kyung-Sun ; Lee, Hye-Mi ; Lee, Min-Ho ; Park, Song-Kyu ; Maeng, Pil-Jae ; Park, Young-Woo ; Lee, Sung-Hou ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1059~1063
Abnormal phenotypes resulting from haploinsufficiency (HI) are due to the loss of one allele. Recent studies in budding yeast have shown that HI originates from insufficient protein levels or from a stoichiometric imbalance between subunits of protein complexes. In humans, however, HI often involves transcription factors. Therefore, the species differences in HI and the molecular mechanisms of species-specific HI remain under investigation. In this study, HI in fission yeast was systematically surveyed. HI in fission yeast affected genes related to signaling and to basic cellular processes, as observed in budding yeast. These results suggest that there are species differences in HI and that the HI that occurs in fission yeast is intermediate to HI in budding yeast and humans.
Probing the Critical Residues for Intramolecular Fructosyl Transfer Reaction of a Levan Fructotransferase
Moon, Keum-Ok ; Choi, Kyoung-Hwa ; Kang, Ho-Young ; Oh, Jeong-Il ; Jang, Se-Bok ; Park, Cheon-Seok ; Lee, Jong-Hoon ; Cha, Jae-Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1064~1069
Levan fructotransferase (LFTase) preferentially catalyzes the transfructosylation reaction in addition to levan hydrolysis, whereas other levan-degrading enzymes hydrolyze levan into a levan-oligosaccharide and fructose. Based on sequence comparisons and enzymatic properties, the fructosyl transfer activity of LFTase is proposed to have evolved from levanase. In order to probe the residues that are critical to the intramolecular fructosyl transfer reaction of the Microbacterium sp. AL-210 LFTase, an error-prone PCR mutagenesis process was carried out, and the mutants that led to a shift in activity from transfructosylation towards hydrolysis of levan were screened by the DNS method. After two rounds of mutagenesis, TLC and HPLC analyses of the reaction products by the selected mutants revealed two major products; one is a di-D-fructose-2,6':6,2'-dianhydride (DFAIV) and the other is a levanbiose. The newly detected levanbiose corresponds to the reaction product from LFTase lacking transferring activity. Two mutants (2-F8 and 2-G9) showed a high yield of levanbiose (38-40%) compared with the wild-type enzyme, and thus behaved as levanases. Sequence analysis of the individual mutants responsible for the enhanced hydrolytic activity indicated that Asn-85 was highly involved in the transfructosylation activity of LFTase.
Asp97 is a Crucial Residue Involved in the Ligation of the [
] Cluster of IscA from Acidithiobacillus ferrooxidans
Jiang, Huidan ; Zhang, Xiaojian ; Ai, Chenbing ; Liu, Yuandong ; Liu, Jianshe ; Qiu, Guanahou ; Zeng, Jia ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1070~1075
IscA was proposed to be involved in the iron-sulfur cluster assembly encoded by the iscSUA operon, but the role of IscA in the iron-sulfur cluster assembly still remains controversial. In our previous study, the IscA from A. ferrooxidans was successfully expressed in Escherichia coli, and purified to be a [
] -cluster-containing protein. Cys35, Cys99, and Cys101 were important residues in ligating with the [
] cluster. In this study, Asp97 was found to be another ligand for the iron-sulfur cluster binding according to site-directed mutagenesis results. Molecular modeling for the IscA also showed that Asp97 was a strong ligand with the [
] cluster, which was in good agreement with the experimental results. Thus, the [
] cluster in IscA from A. ferrooxidans was ligated by three cysteine residues and one aspartic acid.
Expression, Purification, and Characterization of C-Terminal Amidated Glucagon in Streptomyces lividans
Qi, Xiaoqiang ; Jiang, Rong ; Yao, Cheng ; Zhang, Ren ; Li, Yuan ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1076~1080
Glucagon, a peptide hormone produced by alpha-cells of Langerhans islets, is a physiological antagonist of insulin and stimulator of its secretion. In order to improve its bioactivity, we modified its structure at the C-terminus by amidation catalyzed by a recombinant amidase in bacterial cells. The human gene coding for glucagon-gly was PCR amplified using three overlapping primers and cloned together with a rat
-amidase gene in plasmid pMGA. Both genes were expressed under control of the strong constitutive promoter of aph and secretion signal melC1 in Streptomyces lividans. With Phenyl-Sepharose 6 FF, Q-Sepharose FF, SP-Sepharose FF chromatographies and HPLC, the peptide was purified to about 93.4% purity. The molecular mass of the peptide is 3.494 kDa as analyzed by MALDI TOF, which agrees with the theoretical mass value of the C-terminal amidated glucagon. The N-terminal sequence of the peptide was also determined, confirming its identity with human glucagon at the N-terminal part. ELISA showed that the purified peptide amide is bioactive in reacting with glucagon antibodies.
Purification and Properties of a Novel
-Glucosidase, Hydrolyzing Ginsenoside Rb1 to CK, from Paecilomyces Bainier
Yan, Qin ; Zhou, Xin-Wen ; Zhou, Wei ; Li, Xing-Wei ; Feng, Mei-Qing ; Zhou, Pei ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1081~1089
A novel ginsenoside-hydrolyzing
-glucosidase was purified from Paecilomyces Bainier sp. 229 by a combination of Q-Sepharose FF, phenyl-Sepharose CL-4B, and CHT ceramic hydroxyapatite column chromatography. The purified enzyme was a monomeric protein with a molecular mass estimated to be 115 kDa. The optimal enzyme activity was observed at pH 3.5 and
. It was highly stable within pH 3-9 and at temperatures lower than
. The enzyme was specific to
-glucoside. The order of enzyme activities against different types of
-glucosidic linkages was
-(1-4). The enzyme converted ginsenoside Rb1 to CK specifically and efficiently. An 84.3% amount of ginsenoside Rb1, with an initial concentration of 2 mM, was converted into CK in 24 h by the enzyme at
and pH 3.5. The hydrolysis pathway of ginsenoside Rb1 by the enzyme was
. Five tryptic peptide fragments of the enzyme were identified by a newly developed de novo sequencing method of post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. By comparing the five identified peptide sequences with the NCBI database, this purified
-glucosidase proves to be a new protein that has not been reported before.
A Conserved Structure and Function of the YidC Homologous Protein Slr1471 from Synechocystis sp. PCC 6803
GathmannI, Sven ; Rupprecht, Eva ; Kahmann, Uwe ; Schneider, Dirk ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1090~1094
In this article, we show that the orf slr1471 from Synechocystis sp. PCC 6803 codes for a functional member of the YidC/Alb3/Oxa1 protein family, and the encoded protein has a transmembrane topology with a common core structure. Using specific antibodies raised against the Synechocystis YidC homologous protein, we further show that the Synechocystis YidC protein appears to be predominantly localized in the cyanobacterial cytoplasmic membrane. The impact of the described findings for synthesis of membrane proteins and for protein sorting within cyanobacterial cells is discussed.
Rhizobacterial Exopolysaccharides Elicit Induced Resistance on Cucumber
Park, Kyung-Seok ; Kloepper, Joseph W. ; Ryu, Choong-Min ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1095~1100
The role of exopolysaccharides (EPSs) from a plant growth-promoting rhizobacterium, Burkholderia gladioli IN26, on elicitation of induced systemic resistance was investigated. A purified EPS induced expression of PR-1a::GUS on tobacco and elicited induced resistance against Colletotrichum orbiculare on cucumber. The maximum level of disease protection was noted when seeds were soaked in 200 ppm of the EPS. Our results indicate that EPS from specific rhizobacteria can elicit induced resistance and suggest that bacterial EPS might be a useful elicitor of resistance under field conditions.
Characterization of Tailoring Genes Involved in the Modification of Geldanamycin Polyketide in Streptomyces hygroscopicus JCM4427
Shin, Jin-Chul ; Na, Zhu ; Lee, Dong-Ho ; Kim, Won-Cheol ; Lee, Kyeong ; Shen, Yue-Mao ; Paik, Sang-Gi ; Hong, Young-Soo ; Lee, Jung-Joon ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1101~1108
Geldanamycin and its analogs are important anticancer agents that inhibit the newly targeted heat-shock protein (Hsp) 90, which is a chaperone protein in eukaryotic cells. To resolve which geldanamycin biosynthetic genes are responsible for particular post-polyketide synthase (PKS) processing steps and in which order the reactions occur, we individually inactivated candidate genes in Streptomyces hygroscopicus subsp. duamyceticus JCM4427 and isolated and elucidated the structures of intermediates from each mutant. The results indicated that gel7 governs at least one of the benzoquinone ring oxidation steps. The gel16 was found to be involved in double-bond formation between C-4 and C-5 of 4,5-dihydrogeldanamycin, which confirmed our previous findings that this double bond is reduced during the post-PKS modification of the polyketide assembly. In addition, pro-geldanamycin, which does not possess a double bond at C-4/5, was purified from the gel7 and gel8 double-gene-inactivated mutant.
Biotransformation of Ginsenoside Rb1, Crocin, Amygdalin, Geniposide, Puerarin, Ginsenoside Re, Hesperidin, Poncirin, Glycyrrhizin, and Baicalin by Human Fecal Microflora and Its Relation to Cytotoxicity Against Tumor Cells
Kim, Young-Suk ; Kim, Jung-Jin ; Cho, Ki-Ho ; Jung, Woo-Sang ; Moon, Sang-Kwan ; Park, Eun-Kyung ; Kim, Dong-Hyun ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1109~1114
To understand the role of intestinal microflora in the biological effect of functional herbs, which have been used in Korea, Japan, and China as traditional medicines, and suggest new bioactive compounds transformed from herbal constituents, the metabolic activities of the functional herb components (ginsenoside Rb1, crocin, amygdalin, geniposide, puerarin, ginsenoside Re, poncirin, hesperidin, glycyrrhizin, and baicalin) toward their bioactive compounds (compound K, crocetin, benzaldehyde, genipin, daidzein, ginsenoside Rh1, ponciretin, hesperetin, 18b-glycyrrhetic acid, and baicalein) were measured in fecal specimens. The metabolic activities of these components were
, respectively. No differences were found in the metabolic activities of the tested components between males and females, although these metabolic activities between individuals are extensively different. The metabolites of functional herb components showed more potent cytotoxicity against tumor cells than nonmetabolites. These findings suggest that intestinal microflora may activate the pharmacological effect of herbal food and medicines and must be the biocatalytic converter for the transformation of herbal components to bioactive compounds.
Effect of Culture Conditions on Cathepsin B Inhibitor Production by a Marine Bacterium, Pseudomonas sp. Strain PB01
Hoang, Le Thu Van ; Kim, Moon-Moo ; Kim, Se-Kwon ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1115~1120
A novel cathepsin B inhibitor-producing bacterium was isolated from marine sediments and identified based on its 16S rDNA sequence as Pseudomonas sp. strain PB01 (Accession No. EU126129). The growth and enzyme inhibitor production were investigated under various culture conditions. A mixture of organic nitrogen source was required for the optimal production, whereas both glucose and maltose proved to be the effective carbon sources for cathepsin B inhibitor production. Other optimal culture conditions included temperature range between 25 and
, initial medium pH of 6.6, and shaking speed of 200 rpm. Under these optimal conditions, the maximum inhibitory activity from culture broth was approximately 50% after 30 h of cultivation. Additionally, kinetic study revealed that inhibitor production paralleled with cell growth, which suggested that the inhibitor may be a primary metabolite of that bacterium.
Effect of Carrier Size on the Performance of a Three-Phase Circulating-Bed Biofilm Reactor for Removing Toluene in Gas Stream
Sang, Byoung-In ; Yoo, Eui-Sun ; Kim, Byung-J. ; Rittmann, Bruce E. ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1121~1129
A series of steady-state and short-term experiments on a three-phase circulating-bed biofilm reactor (CBBR) for removing toluene from gas streams were conducted to investigate the effect of macroporous-carrier size (1-mm cubes versus 4-mm cubes, which have the same total surface area) on CBBR performance. Experimental conditions were identical, except for the carrier size. The CBBR with 1-mm carriers (the 1-mm CBBR) overcame the performance limitation observed with the CBBR with 4-mm carriers (the 4-mm CBBR): oxygen depletion inside the biofilm. The 1-mm CBBR consistently had the superior removal efficiencies of toluene and COD, higher than 93% for all, and the advantage was greatest for the highest toluene loading,
. The 1-mm carriers achieved superior performance by minimizing the negative effects of oxygen depletion, because they had 4.7 to 6.8 times thinner biofilm depths. The 1-mm carriers continued to provide protection from excess biomass detachment and inhibition from toluene. Finally, the 1-mm CBBR achieved volumetric removal capacities up to 300 times greater than demonstrated by other biofilters treating toluene and related volatile hydrocarbons.
Kinetic Study of pH Effects on Biological Hydrogen Production by a Mixed Culture
Jun, Yoon-Sun ; Yu, Seung-Ho ; Ryu, Keun-Garp ; Lee, Tae-Jin ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1130~1135
The effect of pH on anaerobic hydrogen production was investigated under various pH conditions ranging from pH 3 to 10. When the modified Gompertz equation was applied to the statistical analysis of the experimental data, the hydrogen production potential and specific hydrogen production rate at pH 5 were 1,182 ml and 112.5 ml/g biomass-h, respectively. In this experiment, the maximum theoretical hydrogen conversion ratio was 22.56%. The Haldane equation model was used to find the optimum pH for hydrogen production and the maximum specific hydrogen production rate. The optimum pH predicted by this model is 5.5 and the maximum specific hydrogen production rate is 119.6 ml/g VSS-h. These data fit well with the experimented data(
Extracellular 5-Aminolevulinic Acid Production by Escherichia coli Containing the Rhodopseudomonas palustris KUGB306 hemA Gene
Choi, Han-Pil ; Lee, Young-Mi ; Yun, Cheol-Won ; Sung, Ha-Chin ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1136~1140
The Rhodopseudomonas palustris KUGB306 hemA gene codes for 5-aminolevulinic acid (ALA) synthase. This enzyme catalyzes the condensation of glycine and succinyl-CoA to yield ALA in the presence of the cofactor pyridoxal 5'-phosphate. The R. palustris KUGB306 hemA gene in the pGEX-KG vector system was transformed into Escherichia coli BL21. The effects of physiological factors on the extracellular production of ALA by the recombinant E. coli were studied. Terrific Broth (TB) medium resulted in significantly higher cell growth and ALA production than did Luria-Bertani (LB) medium. ALA production was significantly enhanced by the addition of succinate together with glycine in the medium. Maximal ALA production (2.5 g/l) was observed upon the addition of D-glucose as an ALA dehydratase inhibitor in the late-log culture phase. Based on the results obtained from the shake-flask cultures, fermentation was carried out using the recombinant E. coli in TB medium, with the initial addition of 90 mM glycine and 120 mM succinate, and the addition of 45 mM D-glucose in the late-log phase. The extracellular production of ALA was also influenced by the pH of the culture broth. We maintained a pH of 6.5 in the fermenter throughout the culture process, achieving the maximal levels of extracellular ALA production (5.15 g/l, 39.3 mM).
Optimized Substrate Concentrations for Production of Long-Chain Isomaltooligosaccharides Using Dextransucrase of Leuconostoc mesenteroides B-512F
Lee, Min-Sung ; Cho, Seung-Kee ; Eom, Hyun-Ju ; Kim, So-Young ; Kim, Tae-Jip ; Han, Nam-Soo ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1141~1145
Isomaltooligosaccharide (IMO) is a promising dietary component with prebiotic effect, and the long-chain IMOs are preferred to short chain ones owing to the longer persistence in the colon. To establish the optimal process for synthesis of long-chain IMOs, we systematically examined the reaction condition of dextransucrase of Leuconostoc mesenteroides B-512F by changing the ratio of sucrose to maltose (varying as 1:4, 1:2, 1:1, and 2:1) and amount of each sugar (from 2% to 20%). As a result, a ratio of 2:1 (sucrose to maltose, 10:5% or 20:10%, w/v) was determined as an optimal condition for long-chain IMO synthesis (DP3-DP9) with relatively higher yields (70-90%, respectively).
Riboprint and Virulence Gene Patterns for Bacillus cereus and Related Species
Kim, Young-Rok ; Batt, Carl A. ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1146~1155
A total of 72 Bacillus cereus strains and 5 Bacillus thuringiensis strains were analyzed for their EcoRI ribogroup by ribotyping and for the presence or absence of seven virulence-associated genes. From these 77 strains, 42 distinctive ribogroup were identified using EcoRI, but the two species could not be discriminated by their EcoRI ribogroup. The 77 strains were also examined by PCR for the presence of seven virulence-associated genes, cerAB, pi-plc, entFM, bceT, hblA, hblC, and hblD. All five Bacillus thuringiensis strains were positive for these genes. Although differences in the patterns of virulence genes were observed among the different B. cereus strains, within any given ribogroup the patterns of the seven virulence genes was the same. Pulsed-field gel electrophoresis (PFGE) analysis in combination with available chromosomal maps for a selected group of B. cereus strains revealed significant differences in their chromosome size and the placement of virulence genes. Evidence for significant rearrangements within the B. cereus chromosome suggests the mechanism through which the pattern of virulence-associated genes varies. The results suggest linkage between ribogroups and virulence gene patterns as well as no apparent containment of the latter within any particular species boundary.
Molecular Detection of Human Enteric Viruses in Urban Rivers in Korea
Lee, Cheong-Hoon ; Kim, Sang-Jong ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1156~1163
We performed RT-nested PCR to study the distribution of human enteric viruses in urban rivers in Korea. During 2002-2003, water samples were collected from four rivers in Gyeonggi Province, South Korea. Among 58 samples, 45 (77.6%), 32 (55.2%), 12 (20.7%), 2 (3.4%), 4 (6.9%), and 4 (6.9%) showed positive results with adenoviruses (AdVs), enteroviruses (EVs), reoviruses (ReVs), hepatitis A viruses (HAVs), rotaviruses (RoVs), and sapoviruses (SVs), respectively. According to the binary logistic regression model, the occurrence of each enteric virus, except ReVs and HAVs, was not statistically correlated with the water temperature and levels of fecal coliforms (P<0.05). AdVs were most often detected; only 4 samples (6.9%) were negative for AdVs while positive for other enteric viruses in the studied sites. Our results indicated that monitoring human enteric viruses is necessary to improve microbial quality, and that AdVs detection by PCR can be a useful index for the presence of other enteric viruses in aquatic environments.
Development of Multiplex RT-PCR Assays for Rapid Detection and Subtyping of Influenza Type A Viruses from Clinical Specimens
Chang, Hee-Kyoung ; Park, Jeung-Hyun ; Song, Min-Suk ; Oh, Taek-Kyu ; Kim, Seok-Young ; Kim, Chul-Jung ; Kim, Hyung-Gee ; Sung, Moon-Hee ; Han, Heon-Seok ; Hahn, Youn-Soo ; Choi, Young-Ki ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1164~1169
We developed multiplex RT-PCR assays that can detect and identify 12 hemagglutinin (H1-H12) and 9 neuraminidase (N1-N9) subtypes that are commonly isolated from avian, swine, and human influenza A viruses. RT-PCR products with unique sizes characteristic of each subtype were amplified by multiplex RT-PCRs, and sequence analysis of each amplicon was demonstrated to be specific for each subtype with 24 reference viruses. The specificity was demonstrated further with DNA or cDNA templates from 7 viruses, 5 bacteria, and 50 influenza A virus-negative specimens. Furthermore, the assays could detect and subtype up to
dilution of each of the reference viruses that had an original infectivity titer of
. Of 188 virus isolates, the multiplex RT-PCR results agreed completely with individual RT-PCR subtyping results and with results obtained from virus isolations. Furthermore, the multiplex RT-PCR methods efficiently detected mixed infections with at least two different subtypes of influenza viruses in one host. Therefore, these methods could facilitate rapid and accurate subtyping of influenza A viruses directly from field specimens.
Upregulation of Lipopolysaccharide-Induced Interleukin-10 by Prostaglandin
in Mouse Peritoneal Macrophages
Kim, Hyo-Young ; Kim, Jae-Ryong ; Kim, Hee-Sun ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1170~1178
The cyclopentenone prostaglandins (cyPGs) prostaglandin
) and 15-deoxy-
) have been reported to exhibit antiinflammatory activity in activated monocytes/macrophages. However, the effects of these two cyPGs on the expression of cytokine genes may differ. In this study, we investigated the mechanism of action of
in lipopolysaccharide (LPS)-induced expression of inter leu kin (IL)-10 mRNA in mouse peritoneal macrophages. 15d-
inhibited expression of LPS-induced IL-10, whereas
increased LPS-induced IL-10 expression. This synergistic effect of
on LPS-induced IL-10 expression reached a maximum as early as 2 h after simultaneous
and LPS treatment (
/LPS), and did not require new protein synthesis. The synergistic effect of
was inhibited by GW9662, a specific peroxisome proliferator-activated receptor
antagonist, and Bay-11-7082, a NF-
inhibitor. The extracellular signal-regulated kinases (ERK) inhibitor PD98059 increased the expression of
/LPS-induced IL-10 mRNA, rather than inhibiting the IL-10 expression. Moreover,
inhibited LPS-induced ERK phosphorylation. The synergistic effect of
on LPS-induced IL-10 mRNA and protein production was inhibited by p38 inhibitor PD169316, and
increased LPS-induced p38 phosphorylation. In the case of stress-activated protein kinase/c-Jun
-terminal kinase (SAPK/JNK), the SAPK/JNK inhibitor SP600125 did not inhibit IL-10 mRNA synthesis but inhibited the production of IL-10 protein remarkably. These results suggest that the synergistic effect of
on LPS-induced IL-10 expression is NF-
-dependent and mediated by mitogen-activated protein (MAP) kinases, p38, and SAPK/JNK signaling pathways, and also associated with the
pathway. Our data may provide more insight into the diverse mechanisms of
effects on the expression of cytokine genes.
Chitosan Microspheres Containing Bordetella bronchiseptica Antigens as Novel Vaccine Against Atrophic Rhinitis in Pigs
Kang, Mi-Lan ; Kang, Sang-Gyun ; Jiang, Hu-Lin ; Guo, Ding-Ding ; Lee, Deog-Yong ; Rayamahji, Nabin ; Seo, Yeon-Soo ; Cho, Chong-Su ; Yoo, Han-Sang ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1179~1185
The immune-stimulating activities of Bordetella bronchiseptica antigens containing dermonecrotoxin (BBD) loaded in chitosan microspheres (CMs) have already been reported in vitro and in vivo with a mouse alveolar macrophage cell line (RAW264.7) and mice. Therefore, this study attempted to demonstrate the successful induction of mucosal immune responses after the intranasal administration of BBD loaded in CMs (BBD-CMs) in colostrum-deprived pigs. The BBD was introduced to the CMs using an ionic gelation process involving tripolyphosphate (TPP). Colostrum-deprived pigs were then directly immunized through intranasal administration of the BBD-CMs. A challenge with a field isolate of B. bronchiseptica was performed ten days following the final immunization. The BBD-specific IgG and IgA titers, evident in the nasal wash and serum from the vaccinated pigs, increased with time (p<0.05). Following the challenge, the clinical signs of infection were about 6-fold lower in the vaccinated pigs compared with the nonvaccinated pigs. The grades for gross morphological changes in the turbinate bones from the vaccinated pigs were also significantly lower than the grades recorded for the nonvaccinated pigs (p<0.001). Therefore, the mucosal and systemic immune responses induced in the current study would seem to indicate that the intranasal administration of BBD-CMs may be an effective vaccine against atrophic rhinitis in pigs.
Improving the Productivity of Single-Chain Fv Antibody Against c-Met by Rearranging the Order of its Variable Domains
Kim, Yu-Jin ; Neelamegam, Rameshkumar ; Heo, Mi-Ae ; Edwardraja, Selvakumar ; Paik, Hyun-Jong ; Lee, Sun-Gu ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1186~1190
Single-chain Fv (scFv) antibody against c-Met is expected to be employed in clinical treatment or imaging of cancer cells owing to the important biological roles of c-Met in the proliferation of malignancies. Here, we show that the productivity of scFv against c-Met in Escherichia coli is significantly influenced by the orientation of its variable domains. We generated anti-c-Met scFv antibodies with two different domain orders (i.e.,
), expressed them in the cytoplasm of E. coli trx/gor deleted mutant, and compared their specific activities as well as their productivities. Productivity of total and functional anti-c-Met scFv with
orientation was more than five times higher than that with
format. Coexpression of DsbC enhanced the yield of soluble amounts of anti-c-Met scFv protein for both constructs. The purified scFv antibodies of the two different formats exhibited almost the same antigen-binding activities. We also compared the productivities and specific activities of anti-c-Met diabodies with
formats and obtained similar results to the case of scFv antibodies.
Inhibitory Effects of Lactobacillus plantarum Lipoteichoic Acid (LTA) on Staphylococcus aureus LTA-Induced Tumor Necrosis Factor-Alpha Production
Kim, Han-Geun ; Lee, Seung-Yeon ; Kim, Na-Ra ; Ko, Mi-Yeon ; Lee, Jung-Min ; Yi, Tae-Hoo ; Chung, Sung-Kyun ; Chung, Dae-Kyun ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1191~1196
Staphylococcus aureus is a common etiologic agent for Gram-positive sepsis, and its lipoteichoic acid (LTA) may be important in causing Gram-positive bacterial septic shock. Here, we demonstrate that highly purified LTA (pLTA) isolated from Lactobacillus plantarum inhibited S. aureus LTA (aLTA)-induced TNF-
production in THP-1 cells. Whereas pLTA scarcely induced TNF-
production, aLTA induced excessive TNF-
production. Interestingly, aLTA-induced TNF-
production was inhibited by pLTA pretreatment. Compared with pLTA, aLTA induced a strong signal transduction through the MyD88, NF-
, and MAP kinases. This signaling, however, was reduced by a pLTA pretreatment, and resulted in the inhibition of aLTA-induced TNF-
production. Whereas dealanylated LTAs, as well as native LTAs, contributed to TNF-
induction or TNF-
reduction, deacylated LTAs did not, indicating that the acyl chain of LTA played an important role in the LTA-mediated immune regulation. These results suggest that pLTA may act as an antagonist for aLTA, and that an antagonistic pLTA may be a useful agent for suppressing the septic shock caused by Gram-positive bacteria.
Tunicamycin-Induced ER Stress Upregulates the Expression of Mitochondrial HtrA2 and Promotes Apoptosis Through the Cytosolic Release of HtrA2
Han, Chul ; Nam, Min-Kyung ; Park, Hyo-Jin ; Seong, Young-Mo ; Kang, Seong-Man ; Rhim, Hyang-Shuk ;
Journal of Microbiology and Biotechnology, volume 18, issue 6, 2008, Pages 1197~1202
Recent studies provide some evidence that the HtrA2 protein is intimately associated with the pathogenesis of neurodegenerative disorders and that endoplasmic reticulum (ER) quality control and ER stress-associated cell death play critical roles in neuronal cell death. However, little is known about the intimate relationship between HtrA2 and ER stress-associated cellular responses. In the present study, we have demonstrated that the HtrA2 protein level was gradually and significantly increased by up to to-fold in the mitochondria under tunicamycin (Tm)-induced ER stress, which eventually promoted cell death through the release of HtrA2 into the cytoplasm. Using an ecdysone-inducible mammalian expression system, we demonstrate that the extent of cell death in 293-HtrA2 cells was approximately 20 times higher under Tm-induced ER stress, indicating that the increase in the HtrA2 protein level in the mitochondria itself is necessary but not sufficient for the promotion of cell death. Taken together, these results suggest that HtrA2 may serve as a mediator of ER stress-induced apoptosis and ER-mitochondrial cross-talk in some cellular processes.