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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 16, Issue 12 - Dec 2006
Volume 16, Issue 11 - Nov 2006
Volume 16, Issue 10 - Oct 2006
Volume 16, Issue 9 - Sep 2006
Volume 16, Issue 8 - Aug 2006
Volume 16, Issue 7 - Jul 2006
Volume 16, Issue 6 - Jun 2006
Volume 16, Issue 5 - May 2006
Volume 16, Issue 4 - Apr 2006
Volume 16, Issue 3 - Mar 2006
Volume 16, Issue 2 - Feb 2006
Volume 16, Issue 1 - Jan 2006
Selecting the target year
Rhizosphere Communication: Quorum Sensing by the Rhizobia
He, Xuesong ; Fuqua, Clay ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1661~1677
Rhizobium and related genera are soil bacteria with great metabolic plasticity. These microorganisms survive in many different environments and are capable of eliciting the formation of nitrogen-fixing nodules on legumes. The successful establishment of symbiosis is precisely regulated and requires a series of signal exchanges between the two partners. Quorum sensing (QS) is a prevalent form of population density-dependent gene regulation. Recently, increasing evidence indicates that rhizobial quorum sensing provides a pervasive regulatory network, which plays a more generalized role in the physiological activity of free-living rhizobia, as well as during symbiosis. Several rhizobia utilize multiple, overlapping quorum sensing systems to regulate diverse properties, including conjugal transfer and copy number control of plasmids, exopolysaccharide biosynthesis, rhizosphere-related functions, and cell growth. Genomic and proteomic analyses have begun to reveal the wide range of functions under quorum-sensing control.
Novel Suspension-Phase Enzyme Reaction System Using Insoluble Extrusion Starch as Glycosyl Donor for Intermolecular Transglycosylation of L-Ascorbic Acid
Kim, Tae-Kwon ; Jung, Se-Wook ; Go, Young-Hoon ; Lee, Yong-Hyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1678~1683
A novel suspension-phase enzyme reaction system for the intermolecular transglycosylation of L-ascorbic acid into 2-O-
-D-glucopyranosyl L-ascorbic acid supplementing extrusion starch as the glycosyl donor was developed using cyclodextrin glucanotransferase from Thermoanaerobacter sp. A high conversion yield compared to the conventional soluble-phase enzyme reaction system using cyclodextrins and soluble starch was achieved. The optimal reaction conditions were 2,000 units of cycIodextrin glucanotransferase, 20 g/l of L-ascorbic acid, and 50 g/l of extrusion starch at
for 24 h. The new suspension-phase enzyme reaction system also exhibited several distinct advantages other than a high conversion yield, including a lower accumulation of oligosaccharides and easily separable residual extrusion starch by centrifugation or filtration in the reaction mixture, which will facilitate the purification of 2-O-
-D-glucopyranosyl L-ascorbic acid. The new suspension-phase enzyme reaction system seems to be potentially applicable as the industrial process for the production of thermally and oxidatively stable 2-O-
-D-glucopyranosyl L-ascorbic acid.
Inactivation of Airborne E. coli and B. subtilis Bioaerosols Utilizing Thermal Energy
Lee, Yun-Ha ; Lee, Byung-Uk ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1684~1689
Airborne microorganisms, which are currently termed bioaerosols, have received attention owing to the harmful effects they have on human health. As the concern over airborne microorganisms grows, there also grows an urgent need to study and develop efficient methods for controlling them. In this study, thermal energy using a thermal tube was tested as a control method, mainly against airborne E. coli. For a comparison, B. subtilis var. niger spores were utilized in the experimentation. It was found that the widely known inactivation conditions for microorganisms were not adequate against airborne microorganisms. The experimental results demonstrated the need for extensive studies that should investigate adequate and economic conditions to control against airborne bacteria. In this study, thermal energy exposed by the thermal tube demonstrated an inactivation performance for controlling E. coli bioaerosols.
Effects of Dissolved Oxygen Level on Avermectin
Production by Streptomyces avermitilis in Computer-Controlled Bioreactor Cultures
Song, Sung-Ki ; Jeong, Yong-Seob ; Kim, Pyeung-Hyeun ; Chun, Gie-Taek ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1690~1698
In order to investigate the effect of dissolved oxygen (DO) level on AVM
production by a high yielding mutant of Streptomyces avermitilis, five sets of bioreactor cultures were performed under variously controlled DO levels. Using an online computer control system, the agitation speed and aeration rate were automatically controlled in an adaptive manner, responding timely to the oxygen requirement of the producer microorganism. In the two cultures of DO limitation, the onset of AVM
biosynthesis was observed to casually coincide with the fermentation time when oxygen-limited conditions were overcome by the producing microorganism. In contrast, this phenomenon did not occur in the parallel fermentations with DO levels controlled at around 30% and 40% throughout the entire fermentation period, showing an almost growth-associated mode of AVM
biosynthesis under the environments of high DO levels started much earlier than the corresponding oxygen-limited cultures, leading to a significant enhancement of AVM
production during the exponential stage. Consequently, approximately 6-fold and 9-fold increases in the final AVM
production were obtained in 30% and 40% DO-controlled fermentations, respectively, especially when compared with the culture of severe DO limitation (the culture with 0% DO level during the exponential phase). The production yield (
), volumetric production rate (Qp), and specific production rate (
) of the 40% DO-controlled culture were observed to be 14%, 15%, and 15% higher, respectively, than those of the parallel cultures that were performed under an excessive agitation speed (350 rpm) and aeration rate (1 vvm) to maintain sufficiently high DO levels throughout the entire fermentation period. These results suggest that high shear damage of the high-yielding strain due to an excessive agitation speed is the primary reason for the reduction of the AVM
biosynthetic capability of the producer. As for the cell growth, exponential growth patterns during the initial 3 days were observed in the fermentations of sufficient DO levels, whereas almost linear patterns of cell growth were observed in the other two cultures of DO limitation during the identical period, resulting in apparently lower amounts of DCW. These results led us to conclude that maintenance of optimum DO levels, but not too high to cause potential shear damage on the producer, was crucial not only for the cell growth, but also for the enhanced production of AVM
by the filamentous mycelial cells of Streptomyces avermitilis.
Therapeutic Effects of Probiotics in Patients with Atopic Dermatitis
Yim, Jun-Hee ; Kim, Duk-Han ; Ku, Ja-Kyung ; Kang, Yoon-Sung ; Kim, Mi-Yeon ; Kim, Hyung-Ok ; Chung, Myung-Jun ; Park, Young-Min ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1699~1705
Recent studies have suggested that oral bacteriotherapy with probiotics might be useful for preventing and managing childhood atopic dermatitis (AD). The purpose of this investigation was to evaluate the efficacy and safety of oral treatment with probiotics for adolescent and adult AD patients as well as for childhood AD patients. Sixty-four patients with mild to moderate AD were recruited for treatment with a mixture of four probiotic strains (Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus casei, and Biftdobacterium lactis) twice daily for 8 weeks. The degree of pruritus was determined by a 10-point visual analog scale every other week, and the patients' global assessments of their clinical responses (i.e., better, unchanged, or worse) was done at the end of intervention. The clinical severity of the eczema was evaluated by eczema area and severity index (EASI) score every other week. As laboratory markers, total immunoglobulin E (IgE), eosinophil cationic protein (ECP) in the serum, and cytokine production [interleukin-4 (IL-4), interleukin-10 (IL-10), and
by the peripheral blood mononuclear cells (PBMCs) were measured at the beginning and at the end of intervention. Of the 64 enrolled AD patients, only 50 patients finally completed the 8-week study. After 8-week treatment with probiotics, the EASI score was significantly improved (p<0.0001), 50% of the patients experienced improvement of their eczema, and significant improvement of the pruritus was also observed (p=0.0002). The effect was more pronounced for the patients with very high IgE levels (>1,000 ku/l) or for the patients with moderate disease severity. There was no significant difference in the therapeutic effects between the childhood AD and adolescent and adult AD patients. There were no significant changes of cytokines, as well as the total IgE and ECP levels, in the patients' serum. Treatment with the mixture of four probiotic strains was generally well tolerated. Our results suggest that the treatment with the mixture of four probiotic strains is beneficial for the management of the adolescent and adult AD patients, as well as for the childhood AD patients.
Use of Bioluminescent Indicator Acinetobacter Bacterium for Screening and Characterization of Active Antimicrobial Agents
Haleem Abd-El ; A.M. Desouky ; Zaki Sahar A. ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1706~1712
Because of the need for new antimicrobial substances with novel mechanisms of action, we report here the use of an Acinetobacter reporter system for high-throughput screening of active antimicrobial agents. The bioreporter Acinetobacter strain DF4/PUTK2 carrying luciferase genes luxCDABE was chosen because of its ecological importance and it is widespread in nature. This bioreporter is genetically engineered to emit light constitutively that can be measured in real time by luminometry. Hence, this reporter system was employed to determine the bacteriostatic actions of spent-culture supernatants derived from twelve bacterial isolates. Out of the results, the strongest bioluminescence inhibitory effect of the supernatants was recorded with Bacillus cereus strain BAC (S5). Subsequently, ethyl acetate extracts of extracellular products of strain BAC (S5) were separated by a thin-layer chromatography (TLC). Based on the bioluminescence inhibitory assay, three fractions were found to have antimicrobial activity. One fraction (C) having the strongest antimicrobial activity was further purified using TLC and characterized by IR,
NMR, mass spectrometry, SDS-PAGE, and amino acid composition analysis. The results predicted the presence of 2-pyrrolidone-S-carboxylic acid (PCA) and the octadeconic-acid-like fatty acid. Fraction C also demonstrated a broad inhibitory activity on several Gram-negative and Gram-positive bacteria. In conclusion, the Acinetobacter reporter system shows great potential to be a reliable, sensitive, and real-time indicator of the bacteriostatic actions of the antimicrobial agents.
Rapid and Accurate Detection of Bacillus anthracis Spores Using Peptide-Quantum Dot Conjugates
Park, Tae-Jung ; Park, Jong-Pil ; Seo, Gwi-Moon ; Chai, Young-Gyu ; Lee, Sang-Yup ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1713~1719
A method for the simple, rapid, specific, and accurate detection of Bacillus anthracis spores was developed by employing specific capture peptides conjugated with fluorescent quantum dots (QDs). It was possible to distinguish B. anthracis spores from the spores of B. thuringiensis and B. cereus using these peptide-QD conjugates by flow cytometric and confocal laser scanning microscopic analyses. For more convenient high-throughput detection of B. anthracis spores, spectrofluorometric analysis of spore-peptide-QD conjugates was performed. B. anthracis spores could be detected in less than 1 h using this method. In order to avoid any minor yet false-positive signal caused by the presence of B. thuringiensis spores, the B-Negative peptide, which can only bind to B. thuringiensis, conjugated with another type of QD that fluoresces at different wavelength was also developed. In the presence of mixed B. anthracis and B. thuringiensis spores, the BABA peptide conjugated with QD525 and the B-Negative peptide conjugated with QD585 were able to bind to the former and the latter, specifically and respectively, thus allowing the clear detection of B. anthracis spores against B. thuringiensis spores by using two QD-labeling systems. This capture peptide-conjugated QD system should be useful for the detection of B. anthracis spores.
Kinetic Analysis and Mathematical Modeling of Cr(VI) Removal in a Differential Reactor Packed with Ecklonia Biomass
Park, Dong-Hee ; Yun, Yeoung-Sang ; Lim, Seong-Rin ; Park, Jong-Moon ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1720~1727
To set up a kinetic model that can provide a theoretical basis for developing a new mathematical model of the Cr(VI) biosorption column using brown seaweed Ecklonia biomass, a differential reactor system was used in this study. Based on the fact that the removal process followed a redox reaction between Cr(VI) and the biomass, with no dispersion effect in the differential reactor, a new mathematical model was proposed to describe the removal of Cr(VI) from a liquid stream passing through the differential reactor. The reduction model of Cr(VI) by the differential reactor was zero order with respect to influent Cr(IlI) concentration, and first order with respect to both the biomass and influent Cr(VI) concentrations. The developed model described well the dynamics of Cr(VI) in the effluent. In conclusion, the developed model may be used for the design and performance prediction of the biosorption column process for Cr(VI) detoxification.
Sphingobacterium composti sp. nov., a Novel DNase-Producing Bacterium Isolated from Compost
Ten Leonid N. ; Liu, Qing-Mei ; Im Wan-Taek ; Aslam Zubair ; Lee, Sung-Taik ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1728~1733
A Gram-negative, strictly aerobic, nonmotile, and nonspore-forming bacterial strain, designated
, was isolated from compost and characterized using a polyphasic taxonomical approach. The isolate was positive for catalase and oxidase tests. It could degrade DNA, but was negative for degradation of macromolecules such as casein, collagen, starch, chitin, cellulose, and xylan. The DNA G+C content was 36.0 mol%. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major fatty acids were
3OH (17.2%), and summed feature 4 (
2OH, 14.9%). Comparative 16S rRNA gene sequence analysis showed that strain
fell within the radiation of the cluster comprising members of the genus Sphingobacterium. Strain
exhibited lower than 94% of 16S rRNA gene sequence similarity with respect to the type strains of recognized Sphingobacterium species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain
) should be classified in the genus Sphingobacterium as the type strain of a novel species, for which the name Sphingobacterium composti sp. novo is proposed.
Serial Degradation of Perchloroethylene by Delftia sp. N6 after Dechlorination Using Fenton's Reagent
Lee, Wan-Seok ; Kim, Jang-Eok ; Kim, Hee-Sik ; Ahn, Chi-Yong ; Oh, Hee-Mock ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1734~1739
The degradation of perchloroethylene (PCE) was investigated with the serial treatment of biological reaction after dechlorination using Fenton's reagent. The dechlorination of PCE was expressed using
(dechlorination value), calculated from
mol, and was 2.58 with 5 mM of
of PCE was transformed to
of dichloroacetic acid (DCAA). Biological treatment with Delftia sp. N6 was applied after degradation of PCE by the Fenton reaction. The optical densities indicating cell growth were 0.53/0.10 with/without the Fenton reaction after one day, respectively. The N6 strain degraded 95% of the DCAA produced from PCE by the Fenton reaction within one day. Consequently, it seemed that the serial treatment of a Fenton reaction and biological reaction was effective in the removal of not only PCE, but also DCAA, one of the major metabolites of PCE.
Isolation of a Pseudomonas sp. Capable of Utilizing 4-Nonylphenol in the Presence of Phenol
Chakraborty Joydeep ; Dutta Tapan K. ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1740~1746
Enrichment techniques led to the isolation of a Pseudomonas sp. strain P2 from municipal waste-contaminated soil sample, which could utilize different isomers of a commercial mixture of 4-nonylphenol when grown in the presence of phenol. The isolate was identified as Pseudomonas sp., based on the morphological, nutritional, and biochemical characteristics and 16S rDNA sequence analysis. The
-ketoadipate pathway was found to be involved in the degradation of phenol by Pseudomonas sp. strain P2. Gas chromatography-mass spectrometric analysis of the culture media indicated degradation of various major isomers of 4-nonylphenol in the range of 29-50%. However, the selected ion monitoring mode of analysis of biodegraded products of 4-nonylphenol indicated the absence of any aromatic compounds other than those of the isomers of 4-nonylphenol. Moreover, Pseudomonas sp. strain P2 was incapable of utilizing various alkanes individually as sole carbon source, whereas the degradation of 4-nonylphenol was observed only when the test organism was induced with phenol, suggesting that the degradation of 4-nonylphenol was possibly initiated from the phenolic moiety of the molecule, but not from the alkyl side-chain.
Fractions of Chamaecyparis obtusa Display Antiallergic Effect in RBL2H3 Cells
Choi, In-Gyu ; Kim, Kyung-Jong ; Kim, Young-Mi ; Park, Mi-Jin ; Lee, Yun-Sil ; Jeoung, Doo-Il ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1747~1752
Allergic inflammation results from stimulation of
-hexosaminidase secretion, increased calcium influx, and activation of MAPK pathways. Some fractions of Chamaecyparis obtusa decreased secretion of
-hexosaminidase, calcium influx, ROS, and phosphorylation of ERK. These results suggest that Chamaecyparis obtusa would be valuable for development of allergy therapeutics.
Characterization of an Extracellular Xylanase in Paenibacillus sp. HY-8 Isolated from an Herbivorous Longicorn Beetle
Heo, Sun-Yeon ; Kwak, Jang-Yul ; Oh, Hyun-Woo ; Park, Doo-Sang ; Bae, Kyung-Sook ; Shin, Dong-Ha ; Park, Ho-Yong ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1753~1759
Paenibacillus sp. HY-8 isolated from the digestive tracts of the longicorn beetle, Moechotypa diphysis, produced an extracellular endoxylanase with a molecular weight of 20 kDa estimated by SDS-PAGE. The xylanase was purified to near electrophoretic homogeneity from the culture supernatant after ammonium sulfate precipitation, gel filtration, and ionexchange chromatography. The purified xylanase exhibited the highest activities at pH 6.0 and
values were 7.2 mg/ml and 16.3 U/mg, respectively, for birchwood xylan as the substrate. Nucleotide sequence of the PCR-cloned gene was determined to have the open reading frame encoding a polypeptide of 212 amino acids. The N-terminal amino acid sequence and the nucleotide sequence analyses predicted that the precursor xylanase contained a signal peptide composed of 28 amino acids and a catalytically active 19.9-kDa peptide fragment. The deduced amino acid sequence shared extensive similarity with those of the glycoside hydrolase family 11 of xylanases from other bacteria. The predicted amino acid sequence contained two glutamate residues, previously identified as essential and conserved for active sites in other xylanases of the glycoside hydrolase family 11.
Cloning and Site-Directed Mutagenesis of Musca domestica Acetylcholinesterase for Enhancing Sensitivity to Organophosphorus and Carbamate Insecticides
Kim, Chung-Sei ; Kim, Su-Il ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1760~1772
Mature acetylcholinesterase (AChE) gene (gm, 1,836 bp) was cloned from the housefly and successfully expressed in the E. coli CodonPlus (DE3) RIL system (GM-E, 72 kDa) with a yield of 1,630 mU/g fresh cells. Using the gm, 10 kinds of mutants were constructed and expressed for enhancing sensitivity to insecticides. The sensitivity of these mutants to five kinds of organophosphate (OP) and three carbamate insecticides was investigated by measuring the apparent bimolecular inhibition constant (
). Surprisingly, the sensitivity of quadruple mutant IGFT was enhanced as much as 7-fold for acephate, 164-fold for demeton-S-methyl, 484-fold for dichlorvos, 523-fold for edifenphos, 30-fold for ethoprophos, 30-fold for benfuracarb, 404-fold for carbaryl, and 107-fold for furathiocarb, compared with that of GM-E, although the sensitivity of each single point mutant was slightly increased. These mutational studies indicated that (i) contradictory to Walsh et al. , the residue 327 is the important key residue for enhancing sensitivity as much as the residue 262, (ii) the residue 82 and additional residues of 234, 236, and 585 are also important, and (iii) sensitivity was cooperatively accelerated as the number of strategic mutations increased.
Evaluation of DNA Microarray Approach for Identifying Strain-Specific Genes
Hwang, Keum-Ok ; Cho, Jae-Chang ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1773~1777
We evaluated the usefulness of DNA microarray as a comparative genomics tool, and tested the validity of the cutoff values for defining absent genes in test genomes. Three genome-sequenced E. coli strains (K-12, EDL933, and CFT073) were subjected to comparative genomic hybridization with DNA microarrays covering almost all ORFs of the reference strain K-12, and the microarray results were compared with the results obtained from in silico analyses of genome sequences. For defining the K-12 ORFs absent in test genomes (reference strain-specific ORFs), we applied and evaluated the cutoff level of -1. The average sequence similarity between ORFs, to which corresponding spots showed a log-ratio of>-1, was
. The numbers of spots showing a log-ratio of <-1 (P<0.05, t-test) were 90 (2.5%) and 417 (10.6%) for the EDL933 genome and the CFT073 genome, respectively. Frequency of false negatives (FN) was ca. 0.2, and the cutoff level of -1.3 was required to achieve the FN of 0.1. The average sequence similarity of the false negative ORFs was
, indicating that the majority of the false negatives were caused by highly divergent genes. We concluded that the microarray is useful for identifying missing or divergent ORFs in closely related prokaryotic genomes.
Quantification of Genetically Modified Canola GT73 Using TaqMan Real-Time PCR
Kim, Jae-Hwan ; Song, Hee-Sung ; Kim, Dong-Hern ; Kim, Hae-Yeong ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1778~1783
Event-specific PCR detection methods are the primary trend in genetically modified (GM) plant detection owing to their high specificity based on the flanking sequence of the exogenous integrant. Therefore, this study describes a real-time PCR system for event-specific GM canola GT73, consisting of a set of primers, TaqMan probe, and single target standard plasmid. For the specific detection of GT73 canola, the 3'-integration junction sequence between the host plant DNA and the integrated specific border was targeted. To validate the proposed method, test samples of 0, 1, 3, 5, and 10% GT73 canola were quantified. The method was also assayed with 15 different plants, and no amplification signal was observed in a real-time PCR assay with any of the species tested, other than GT73 canola.
Screening of Peptides Bound to Anthrax Protective Antigen by Phage Display
Kim, Joung-Mok ; Park, Hye-Yeon ; Choi, Kyoung-Jae ; Jung, Hoe-Il ; Han, Sung-Hwan ; Lee, Jae-Seong ; Park, Joon-Shik ; Yoon, Moon-Young ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1784~1790
Bacillus anthracis is a causative agent of anthrax. Anthrax toxins are composed of a protective antigen (PA), lethal factor (LF), and edema factor (EF), in which the PA is a central mediator for the delivery of the two enzymatic moieties LF and EF. Therefore, the PA has been an attractive target in the prevention and vaccinization for anthrax toxin. Recently, it has been reported that the molecule consisting of multiple copies of PA-binding peptide, covalently linked to a flexible polymer backbone, blocked intoxification of anthrax toxin in an animal model. In the present study, we have screened novel diverse peptides that bind to PA with a high affinity (picomolar range) from an M13 peptide display library and characterized the binding regions of the peptides. Our works provide a basis to develop novel potent inhibitors or diagnostic probes with a diverse polyvalence.
Metabolism of Ginsenoside Rg5, a Main Constituent Isolated from Red Ginseng, by Human Intestinal Microflora and Their Antiallergic Effect
Shin, Yong-Wook ; Bae, Eun-Ah ; Han, Myung-Joo ; Kim, Dong-Hyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1791~1798
When ginsenoside Rg5, a main component isolated from red ginseng, was incubated with three human fecal microflora for 24 h, all specimens showed hydrolyzing activity: all specimens produced ginsenoside Rh3 as a main metabolite, but a minor metabolite
-dihydroxydammar-21(22),24-diene (DD) was observed in two specimens. To evaluate the antiallergic effect of ginsenoside Rg5 and its metabolites, the inhibitory effect of ginsenoside Rg5 and its metabolite ginsenoside Rh3 against RBL-2H3 cell degranulation, mouse passive cutaneous anaphylaxis (PCA) reaction induced by the IgE-antigen complex, and mouse ear skin dermatitis induced by 12-O-tetradecanoilphorbol-13-acetate (TPA) were measured. Ginsenosides Rg5 and Rh3 potently inhibited degranulation of RBL-2H3 cells. These ginsenosides also inhibited mRNA expression of proinflammatory cytokines IL-6 and
in RBL-2H3 cells stimulated by IgE-antigen. Orally and intraperitoneally administered ginsenoside Rg3 and orally administered ginsenoside Rg5 to mice potently inhibited the PCA reaction induced by IgE-antigen complex. However, intraperitoneally administered ginsenoside Rg5 nearly did not inhibit the PCA reaction. These ginsenosides not only suppressed the swelling of mouse ears induced by TPA, but also inhibited mRNA expression of cyclooxygenase-2,
, and IL-4 and activation of transcription factor NF-kB. These inhibitions of ginsenoside Rh3 were more potent than those of ginsenoside Rg5. These findings suggest that ginsenoside Rg5 may be metabolized in vivo to ginsenoside Rh3 by human intestinal microflora, and ginsenoside Rh3 may improve antiallergic diseases, such as rhinitis and dermatitis.
Development of a Food-Grade Integration Vector for Heterologous Gene Expression and Protein Secretion in Lactococcus lactis
Jeong, Do-Won ; Lee, Jong-Hoon ; Kim, Kyoung-Heon ; Lee, Hyong-Joo ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1799~1808
A food-grade integration vector based on site-specific recombination was constructed. The 5.7-kb vector, pIMA20, contained an integrase gene and a phage attachment site originating from bacteriophage A2, with the
-galactosidase gene from Lactobacillus plantarum KCTC 3104 as a selection marker. pIMA20 was also equipped with a controllable promoter of nisA (
) and a signal peptide-encoding sequence of usp45 (
) for the production and secretion of foreign proteins. pIMA20 and its derivatives mediated site-specific integration into the attB-like site on the Lactococcus lactis NZ9800 chromosome. The vector-integrated recombinant lactococci were easily detected by the appearance of blue colonies on a medium containing
and also by their ability to grow on a medium containing melibiose as the sole carbon source. Recombinant lactococci maintained these traits in the absence of selection pressure during 100 generations. The
gene from Bacillus licheniformis, lacking a signal peptide-encoding. sequence, was inserted downstream of
in pIMA20, and the plasmid was integrated into the L. lactis chromosome.
was successfully produced and secreted by the recombinant L. lactis, controlled by the addition and concentration of nisin.
Cloning and Overexpression of 4-
-Glucanotransferase from Thermus brockianus (TBGT) in E. coli
Bang, Bo-Young ; Kim, Han-Jo ; Kim, Hae-Yeong ; Baik, Moo-Yeol ; Ahn, Soon-Cheol ; Kim, Chung-Ho ; Park, Cheon-Seok ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1809~1813
A gene corresponding to 4-
) was cloned from the thermophilic bacterium Thermus brockianus. The nucleotide sequence analysis showed that the
gene is composed of 1,503 nucleotides and encodes a polypeptide that is 500 amino acids long with a calculated molecular mass of 57,221 Da. The deduced amino acid sequences of Thermus brockianus
(TBGT) exhibited a high level of similarity to the amino acid sequence of
of Thermus thermophilus (86%), but low level of homology to that of E. coli (26%). The TBGT gene was overexpressed in E. coli BL21, and the corresponding recombinant enzyme was efficiently purified by Ni-NTA affinity chromatography. The enzymatic characteristics revealed that optimal pH and temperature were pH 6 and
, respectively. Most interestingly, TBGT reacted with small oligosaccharides, especially maltotriose, to form various maltooligosaccharides by using its disproportionation activity.
Pulsed-Field Gel Electrophoresis-Based Molecular Typing Reveals a Shift in the Major Type of Vibrio cholerae O1 Isolated in Korea
Kim, Seong-Han ; Kim, Jun-Young ; Kang, Yeon-Ho ; Park, Yong-Keun ; Lee, Bok-Kwon ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1814~1818
Vibrio cholerae O1 El Tor isolates (n=242), collected in Korea between 1991 and 2002, were classified by NotI-digested pulsed-field gel electrophoresis (PFGE). The major types were Al before 1998 and B after 1999, among both domestic and imported cases. The prevalent PFGE types among domestic cases were consistent with the prevalent types among imported cases in the same year. These results suggest a close relationship between the domestic and imported cases of cholera in Korea.
Characterization of Naphthalene-Degrading Pseudomonas Species Isolated from Pollutant-Contaminated Sites: Oxidative Stress During their Growth on Naphthalene
Kang, Yoon-Suk ; Kim, Young-Jun ; Jeon, Che-Ok ; Park, Woo-Jun ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1819~1825
Four naphthalene-degrading bacteria (Pseudomonas sp. strains O1, W1, As1, and G1) were isolated feom pollutant-contaminated sites. Examination of their substrate utilization and analyses of key naphthalene-catabolic regulatory genes revealed that the pathway and regulation of naphthalene-degradation in all four strains resemble those of NAH7 from P. putida G7. Superoxide anion production, superoxide dismutase activity, and catalase activity during their growth on naphthalene-amended medium increased significantly, compared with those with glucose-amended medium. Addition of ascorbate, an antioxidant, or ferrous iron (
) increased the growth rates of all tested microorganisms on naphthalene. Northern blot and HPLC analyses showed that both nahA gene expression and naphthalene degradation increased under those conditions. Our data suggest that naphthalene degradation can impose severe oxidative stress, and defenses against oxidative stress would play an important role in the metabolism of naphthalene.
Thermococcus onnurineus sp. nov., a Hyperthermophilic Archaeon Isolated from a Deep-Sea Hydrothermal Vent Area at the PACMANUS Field
Bae, Seung-Seob ; Kim, Yun-Jae ; Yang, Sung-Hyun ; Lim, Jae-Kyu ; Jeon, Jeong-Ho ; Lee, Hyn-Sook ; Kang, Sung-Gyun ; Kim, Sang-Jin ; Lee, Jung-Hyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1826~1831
A novel hyperthermophilic, anaerobic, heterotrophic archaeon, designated strain
, was isolated from a deep-sea hydrothermal vent area (depth, 1,650 m) within the Papua New Guinea-Australia-Canada-Manus (PACMANUS) field. Cells of this strain were motile by means of polar flagella, coccoid-shaped with a diameter of approximately
, and occurred as single cells. Optimal temperature, pH, and NaCl concentration for growth were
, 8.5, and 3.5%, respectively. The new isolate was an obligate heterotroph that utilized yeast extract, beef extract, tryptone, peptone, casein, and starch as carbon and energy sources. Elemental sulfur was required for growth and was reduced to hydrogen sulfide. The G+C content of the genomic DNA was 52.0 mol%. Phylogenetic analysis of the 16S rRNA gene indicated that strain
belongs to the genus Thermococcus, and the organism is most closely related to T. gorgonarius, T. peptonophilus, and T. celer; however, no significant homology was observed among species by DNA-DNA hybridization. Strain
therefore represents a novel species for which the name Thermococcus onnurineus sp. novo is proposed. The type strain is
(=KCTC 10859, =JCM 13517).
Screening and Purification of a Novel Transaminase Catalyzing the Transamination of Aryl
Acid from Mesorhizobium sp. LUK
Kim, Ju-Han ; Kyung, Do-Hyun ; Yun, Hyung-Don ; Cho, Byung-Kwan ; Kim, Byung-Gee ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1832~1836
Mesorhizobium sp. LUK, which utilizes 3-amino-3-phenylpropionic acid as the sole source of nitrogen with high enantioselectivity (E(S)>100), was isolated using enrichment culture. The enzyme involved in the utilization of (S)-3-amino-3-phenylpropionic acid was confirmed to be a transaminase and was purified by 235-folds with a specific activity of 0.72 U/mg. The molecular weight of the purified protein was ca. 47 kDa and the active enzyme was determined as a dimer on gel filtration chromatography. The N-terminal sequence was obtained from the purified protein. Spontaneous decarboxylation of produced
acids was observed during the chiral resolution of 3-amino-3-phenylpropionic acid.
Definitive Nomenclature of GES/IBC-Type Extended-Spectrum
Weldhagen Gerhard F. ; Kim, Bok-Hee ; Cho, Chan-Hwi ; Lee, Sang-Hee ;
Journal of Microbiology and Biotechnology, volume 16, issue 11, 2006, Pages 1837~1840
Because there are no unified nomenclature systems for either GES-type or IBC-type extended-spectrum
(ESBLs), we propose a unified and definitive nomenclature system for GES/IBC-type ESBLs. This proposed nomenclature update is greatly helpful in two points: (i) it would not confuse microbiologists studying GES-type ESBLs, fundamentally preventing misleading nomenclature of these antibiotic resistance genes, and (ii) the definitive renaming of GES/IBC-type ESBLs can help some researchers to correctly designate new GES-type ESBLs such as novel enzymes identified trom some nationwide surveys.