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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
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Transcription Analysis of Daptomyc in Biosynthetic Genesin Streptomyces roseosporus
Rhee, Ki-Hyeong ; Davies, Julian ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1841~1848
Insights into gene expression have the potential for improvement of antibiotic yield and the development of robust production hosts for use in recombinant biomolecule production.
(daptomycin for injection) is a recently approved antibiotic active against many Gram(+) pathogens, including those resistant to methicillin, vancomycin, and fluoroquinolones. Daptomycin is produced as a secondary metabolite by Streptomyces roseosporus. A 128 kb region of DNA including the daptomycin biosynthetic gene cluster (dpt) has been cloned. and sequenced. Using a selected array of nucleic acid probes representing this region, we compared the expression levels of the dpt genes between S. roseosporus wild-type (WT) and derived S. roseosporus high-producer of daptomycin (HP). We observed that the majority of the biosynthetic genes were upregulated in HP compared with WT; a total of 12 genes, including those encoding daptomycin synthetase, showed consistently and significantly higher expression levels, at least 5-fold, in HP compared with WT. In contrast, some genes, flanking the dpt cluster, were expressed at higher levels in the WT strain. The expression of housekeeping genes such as S. roseosporus rpsL, rpsG, and 16S (positive controls) and presumptive intergenic regions in the dpt cluster (negative control) were identical in the two strains. In addition, we compared transcription during the early, mid-log, and early-stationary phases of growth in the HP strain. The same set of genes was upregulated and downregulated under all conditions examined; housekeeping genes showed no relative change in expression level over the periods of growth tested. Analyses of this type would be of value in studies of strain improvement and also for the identification of gene regulation processes that are important for secondary metabolite production.
A Novel Approach to the Production of Hyaluronic Acid by Streptococcus zooepidemicus
Kim, Sae-Jin ; Park, Sung-Yurb ; Kim, Chan-Wha ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1849~1855
It has been shown that the initial conditions of bacterial cultivation are extremely important for the successful production of hyaluronic acid (HA) by fermentation. We investigated several parameters that affect cell growth rate and the productivity and molecular weight of hyaluronic acid--i.e., agitation speed, aeration rate, culture temperature, pH, and pressure--to determine how to optimize the production of HA by Streptococcus zooepidemicus on an industrial scale. Using a 30-1 jar fermentor under laboratory conditions, we achieved maximum HA productivity and biomass when the agitation speed and aeration rate were increased simultaneously. By shifting the temperature downward from 35
at key levels of cell growth during the fermentation process, we were able to obtain HA with a molecular weight of
at a productivity of 5.3 g/l. Moreover, we reproduced these optimized conditions successfully in three 30-1 jar fermentors. By reproducing these conditions in a 3-
fermentor, we were able to produce HA with a molecular weight of
at a productivity of 5.4 g/l under large-scale conditions.
Xylanase Production by Bacillus sp. A-6 Isolated from Rice Bran
Lee, Jun-Ho ; Choi, Suk-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1856~1861
A Bacillus sp. A-6 strain that produced xylanase was isolated from rice bran. The optimal temperature and pH for xylanase activity of the culture supernatant of Bacillus sp. A-6 were 40
and pH 7, respectively. The optimal temperature and pH for xylanase production in the xylan medium were 30
and pH 9, respectively. The optimal concentrations of oat spelt xylan and peptone for xylanase production were 0.5% and 1.5%, respectively. The best nitrogen sources for xylanase production was beef extract, but xylanase production was also supported comparably by tryptone and peptone. The bacterial growth in the optimal xylan medium reached stationary growth phase after 12 h of incubation. The xylanase production in the culture supernatant increased dramatically during the initial 12 h exponential growth phase and then remained constant at 23.8-24.5 unit/ml during the stationary growth phase. The pH of the culture medium decreased from 8.8 to 6.7 during the exponential growth phase and subsequently increased to 8.1 during the stationary growth phase. Rice bran, sorghum bran, and wheat bran as well as oat spelt xylan induced xylanase production. The xylanase production was repressed when glucose was added to the xylan-containing medium.
Halobacillus blutaparonensis sp. nov., a Moderately Halophilic Bacterium Isolated from Blutaparon portulacoides Roots in Brazil
Barbosa Deyvison Clacino ; Bae Jin-Woo ; Weid Irene Von Der ; Vaisman Natalie ; Nam Young-Do ; Chang Ho-Won ; Park Yong-Ha ; Seldin Lucy ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1862~1867
A moderately halophilic, Gram-positive, spore-forming bacterium was isolated from the roots of Blutaparon portulacoides, a plant found in sandy soil parallel to the beach line in Restinga de Jurubatiba, Rio de Janeiro, Brazil. The strain, designated
, was motile and strictly aerobic with rod-shaped cells. It grew in the absence of NaCl and up to 20% NaCl, and was able to hydrolyze casein and starch. Strain
had a cell-wall peptidoglycan based on L-Orn-D-Asp, the predominant menaquinone present was menaquinone-7 (MK-7), diaminopimelic acid was not found, and anteiso-
were the major fatty acids. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain
belonged to the genus Halobacillus and exhibited 16S rRNA gene similarity levels of 97.8-99.4% with the type strains of the other nine Halobacillus species. The DNA-DNA relatedness of strain
with H. trueperi, the closest relative as regards 16S rRNA gene similarity, and H. locisalis was 21% and 18%, respectively. Therefore, on the basis of phenotypic, genotypic, and phylogenetic data, strain
) should be placed in the genus Halobacillus as a member of a novel species, for which the name Halobacillus blutaparonensis sp. nov. is proposed.
Isolation of a Novel Gellan-Depolymerizing Bacillus sp. Strain YJ-1
Jung, Yu-Jin ; Park, Cheon-Seok ; Lee, Hyeon-Gyu ; Cha, Jae-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1868~1873
A novel microorganism that could degrade high molecular weight gellan was screened and isolated from soil. On gellan plate, the microorganism grew well and completely liquefied the plate. The gellan-degrading microorganism was isolated by pure culture on glucose and nutrient agar medium afterwards. The 16S rDNA sequence analysis and biochemical tests using an API 50CHB/20E kit revealed that the strain belonged to Bacillus sp. The isolate, named as Bacillus sp. YJ-1, showed optimum gellan-degrading activity in 0.5% gellan medium at pH 7.5 and 37
. The activity was measured and evaluated by the thiobarbituric acid and thin-layer chromatography method. Mass spectrometry revealed that the major gellan.. depolymerized product was an unsaturated tetrasaccharide consisting of
-D-glucose, which is a dehydrated repeating unit of gellan, thus the enzyme was identified as gellan lyase. When the gellan was present in the medium, the gellan-degrading activity was much higher than that in glucose-grown cells. These results indicate that in the presence of gellan, Bacillus sp. YJ-1 is able to metabolize the gellan by inducing gellan-degrading enzymes that can degrade gellan into small molecular weight oligosaccharides, and then the gellan. depolymerized products are taken up by the cells and utilized by intracellular enzymes.
Flocculation of an Isolated Flocculent Yeast, Candida tropicalis HY200, and its Application for Efficient Xylitol Production Using Repeated-Batch Cultivation
Kang, Heui-Yun ; Kim, Yong-Sung ; Seo, Jin-Ho ; Ryu, Yeon-Woo ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1874~1881
Flocculation of Candida tropicalis HY200 was systemically investigated to elucidate its mechanism, and used for cell cycles in repeated-batch cultivations for the production of xylitol from xylose. Flocculation occurred only after the late exponential phase of growth in the culture media and buffer within the narrow pH range of 3.0-5.0. The flocculation was completely inhibited by treatments of cells with proteases and partially reduced by treatments with carbohydrate-hydrolyzing enzymes and by the presence of mannose and glucose. The addition of calcium ions significantly enhanced the flocculation during cultivation, which was completely abolished by the addition of EDTA. The flocculent yeast HY200 provided repeated-batch cultivations employing cell recycles by flocculation over 6 rounds of cultivation for the production of xylitol from xylose, resulting in a relatively high productivity of averaged 4.6 g xylitol/l h over six batches and maximal 6.3 g xylitol/l h in the final sixth batch. Cell recycle by flocculation was fast and convenient, which could be applicable for the industrial scale of xylitol production.
Some Universal Characteristics of Intertidal Bacterial Diversity as Revealed by 16S rRNA Gene-Based PCR Clone Analysis
Shuang, J.L. ; Liu, C.H. ; An, S.Q. ; Xing, Y. ; Zheng, G.Q. ; Shen, Y.F. ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1882~1889
A 16S rDNA clone library was generated to investigate the bacterial diversity in intertidal sediment from the coast of the Yellow Sea, P. R. China. A total of 102 clones were sequenced and grouped into 73 OTUs using a phylogenetic approach. The sequenced clones fell into 11 bacterial lineages: Proteobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Acidobacteria, Actinobacteria, Firmicutes, Spirochaetes, and candidate divisions of BRCl, OP3, and OP1l. Based on a phylogenetic analysis of these bacteria, together with the ten most closely related sequences deposited in the GenBank, it was concluded that intertidal bacteria are most likely derived from marine bacteria with a remarkable diversity, and some are particularly abundant in intertidal sediment.
Specific Light Uptake Rate Can be Served as a Scale-Up Parameter in Photobioreactor Operations
Lee, Ho-Sang ; Kim, Z-Hun ; Jung, Sung-Eun ; Kim, Jeong-Dong ; Lee, Choul-Gyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1890~1896
Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate (
), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of
cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was
cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper
is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.
Functions of the C-Terminal Region of Chitinase ChiCW from Bacillus cereus 28-9 in Substrate-Binding and Hydrolysis of Chitin
Huang, Chien-Jui ; Chen, Chao-Ying ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1897~1903
In order to investigate the functions of the C-terminal region of chitinase ChiCW of Bacillus cereus 28-9, a C-terminal truncated enzyme, ChiCW
FC, was expressed in Escherichia coli and purified to homogeneity for biochemical characterization. Compared with ChiCW, ChiCW
FC exhibited higher chitinase activity at high temperature and pH, but expressed lower hydrolytic and binding activities toward insoluble substrates. In addition, kinetic properties indicated that ChiCW
MC hydrolyzed oligomeric and polymeric substrates less efficiently than ChiCW. These results suggest that the C-terminal region of ChiCW plays important roles in substrate binding and hydrolysis of chitin. In addition, the biological meaning of C-terminal proteolytic modification of ChiCW is discussed.
Production and Characterization of an Anti-Angiogenic Agent front Saccharomyces cerevisiae K-7
Jeong, Seung-Chan ; Lee, Dae-Hyoung ; Lee, Jong-Soo ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1904~1911
The cell-free extracts of 250 yeasts were screened for their in vitro anti-angiogenic activity, to develop a new cancer metastasis inhibitor. Saccharomyces cerevisiae K-7 was selected as the producer of the anti-angiogenic agent, because it had the highest anti-angiogenic activity. The anti-angiogenic agent was produced maximally from hydrolysates of Saccharomyces cerevisiae K-7, when the yeast was cultured in yeast extract-peptone-dextrose medium at 30
for 24 h, and cell-free extracts were than digested with pepsin for 4 h at 37
. The anti-angiogenic agent was further purified by ultrafiltration, Sephadex G-25 gel permeation chromatography and reverse-phase HPLC, and the anti-angiogenic activity of the final purified preparation was 72.7% at 10
M/egg. The purified anti-angiogenic agent was found to originate from the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) molecule of Saccharomyces cerevisiae K-7, and its peptide sequence was Val-Ser-Trp-Tyr-Asp-Asn-Glu-Tyr-Gly-Tyr-Ser-Thr-Arg-Val-Val-Asp. In the MTT assay, the shape of the HT-l 080 cell was clearly changed to a circular type at 0.2 mM purified anti-angiogenic agent. This result indicated that the growth of the HT-I080 cell was significantly inhibited at 0.2 mM of the purified anti-angiogenic agent. The MMP activity of the treated HT-l080 cells was not affected, evidenced by the gelatin zymography, indicating that the anti-angiogenic mechanism of the purified anti-angiogenic agent is not mediated through MMP activity.
Analysis of a Prodigiosin Biosynthetic Gene Cluster from the Marine Bacterium Hahella chejuensis KCTC 2396
Kim, Doc-Kyu ; Park, Yon-Kyoung ; Lee, Jong-Suk ; F. Kim, Ji-Hyun ; Jeong, Hae-Young ; Kim, Beom-Seok ; Lee, Choong-Hwan ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1912~1918
Marine bacterium Hahella chejuensis KCTC 2396 simultaneously produced red antibiotic prodigiosin and undecylprodiginine. A complete set of the prodigiosin biosynthetic gene cluster has been cloned, sequenced, and successfully expressed in a heterologous host. Sequence analysis of the gene cluster revealed 14 ORFs showing high similarity to pig and red genes from Serratia spp. and Streptomyces coelicolor A3(2), respectively, and the gene organization was almost: similar to that of pig genes. These genes were named hap for Hahella prodigiosin, and determined to be transcribed as a single operon, by RT-PCR experiment. Based on the hap gene mutagenesis experiments and comparative analysis with pig and red genes, we propose a prodigiosin-biosynthetic pathway in KCTC 2396.
MethA Fibrosarcoma Cells Expressing Membrane-Bound Forms of IL-2 Enhance Antitumor Immunity
Sonn, Chung-Hee ; Yoon, Hee-Ryung ; Seong, In-Ock ; Chang, Mi-Ra ; Kim, Yong-Chan ; Kang, Han-Chul ; Suh, Seok-Cheol ; Kim, Young-Sang ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1919~1927
Tumor cells genetically engineered to secrete cytokines are effective in tumor therapy, but various unexpected side effects are observed, which may result from the bulk activation of various bystander cells. In this study, we tested tumor vaccines expressing various membrane-bound forms of IL-2 (mbIL-2) on MethA fibrosarcoma cells to focus antitumor immune responses to CTL. Chimeric forms of IL-2 with whole CD4, deletion forms of CD4, and TNF were expressed on the tumor cell surface, respectively. Tumor clones expressing mbIL-2 or secretory form of IL-2 were able to support the cell growth of CTLL-2, an IL-2-dependent T cell line, and the proliferation of spleen cells from 2C TCR transgenic mice that are responsive to the
MHC class I complex. Expression of mbIL-2 on tumor cells reduced the tumorigenicity of tumor cells, and the mice that once rejected the live IL-2/TNF tumor clone acquired systemic immunity against wild-type MethA cells. The IL-2/TNF clone was inferior to other clones in tumor formation, and superior in the stimulation of the CD8+ T cell population in vitro. These results suggest that the IL-2/TNF clone is the best tumor vaccine, and may stimulate CD8+ T cells by direct priming. Expression of IL-2/TNF on tumor cells may serve as an effective gene therapy method to ameliorate the side effects encountered in the recombinant cytokine therapy and the conventional cytokine gene therapy using the secretory form of IL-2.
Mediation of Rubradirin Resistance by ABC Transporters (RubT1) from Streptomyces achromogenes var. rubradiris NRRL3061
Lamichhane, Janardan ; Oh, Tae-Jin ; Lee, Hei-Chan ; Liou, Kwang-Kyoung ; Kim, Chun-Gyu ; Sohng, Jae-Kyung ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1928~1934
The rubradirin biosynthetic gene cluster harbors 58 ORFs within a 105.6-kb sequence, which includes all of the genes responsible for the synthesis of rubradirin, as well as the primary genes relevant to regulatory, resistance, and transport functions. This gene cluster also harbors a resistance-mediating ABC transporter, RubT1, which is located at the most upstream position in the cluster. In the present study, RubT1 was expressed heterologously in E. coli, and the resistance affinity of RubT1 was determined by an antibacterial activity test, as well as by HPLC and ESI-MS analyses. Evidence clearly demonstrates that RubTl mediates rubradirin resistance as an ABC transporter.
Cloning and Analysis of Medium-Chain-Length Poly(3-Hydroxyalkanoate) Depolymerase Gene of Pseudomonas luteola M13-4
Park, In-Jae ; Rhee, Young-Ha ; Cho, Nam-Young ; Shin, Kwang-Soo ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1935~1939
The gene encoding the extracellular medium-chain-length poly(3-hydroxyalkanoate) (MCL-PHA) depolymerase of Pseudomonas luteola Ml3-4,
, was cloned and analyzed. It was found to be 849 bp, with a deduced protein of 282 amino acids, and was revealed to have a typical leader peptide at its N terminus. The amino acid sequence of
revealed relatively low identity (69 to 72%) with those of other Pseudomonas MCL-PHA depolymerases. In comparison with the amino acid sequences of all available MCL-PHA depolymerases, the depolymerase was found to consist of three domains in sequential order; signal peptide, an N-terminal substrate binding domain, and a catalytic domain, indicating that
belongs to the type IV depolymerases family. The enzyme also contained Asn as an oxyanion hole amino acid.
Analysis of Influence of Environmental Conditions on Ganoderic Acid Content: in Ganoderma lucidum Using Orthogonal Design
Li Na ; Liu Xiao Hua ; Zhou Jie ; Li Yu Xiang ; Zhao Ming Wen ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1940~1946
The influence of environmental conditions on the ganoderic acid (GA) content in the fungus Ganoderma lucidum was investigated using a one-factor-at-a-time design and orthogonal design. Among the various medium components examined, sucrose, soybean powder or peptone, ferrous sulfate, and pH 6.0 were the most suitable carbon source (factor A), nitrogen source (factor B), mineral source (factor C), and initial pH (factor D), respectively, for the GA content in the one-factor-at-a-time design. According to the orthogonal design, the order of effect for the four factors on the GA content was A>C>D>B. The best level of factor A was
(sucrose) with a value of +0.34 mg/100 mg DW. The optimal treatment combination was
with which the GA content reached up to 2.63
0.011 mg/100 mg DW. The interactions between the mineral ion and the nitrogen source, and the mineral ion and the pH were both highly significant (P<0.01). The highest interaction effect was (
) with a value of +0.19 mg/100 mg DW, which was higher than the level effect value for
(peptone) and D
(pH 5.0). Therefore, the results proved that interactions between factors cannot be ignored. The results also indicated the importance of the interactions between the factors, which may help to understand the metabolic pathway leading to triterpene biosynthesis and the expression and regulation of the key enzymes involved.
Enhanced Production of Phaeodactylum tricornutum (Marine Diatoms) Cultured on a New Medium with Swine Wastewater Fermented by Soil Bacteria
Kim, Mi-Kyung ; Chang, Moo-Ung ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1947~1953
There have been a number of studies of methods for recycling animal wastewater to provide new bioresources. In the present work, a marine algal culture medium, designated KEP II, was prepared by adding swine waste (3% v/v) fermented by soil bacteria to a dilution of f/2 culture medium (CT). When Phaeodactylum tricornutum was grown in batch culture in KEP II, the cells lasted long at the exponential phase producing the specific growth rate and biomass; the production of total amino acids and secondary metabolites rose up to 5-fold. It also substantially enhanced the maximum quantum yield of photo system (PS) II of P. tricornutum, greatly increased the level of thylakoid membranes containing PS, and stimulated the production of pyrenoids, including enzymes for
fixation in chloroplasts. KEP II should improve the cost efficiency of industrial mass batch cultures and the value of microalgae for long-term preservation of fresh aquaculture feed as well as production of anticancer and antioxidant agents. Specifically, a low-cost medium for growing the diatoms of aquaculture feed will be economically advantageous.
Effect of Exopolymers from Aureobasidium pullulans on Formalin-Induced Chronic Paw Inflammation in Mice
Kim, Hyeong-Dong ; Cho, Hyung-Rae ; Moon, Seung-Bae ; Shin, Hyun-Dong ; Yang, Kun-Ju ; Park, Bok-Ryeon ; Jang, Hee-Jeong ; Kim, Lin-Su ; Lee, Hyeung-Sik ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1954~1960
The effects of the exopolymers of Aureobasidium pullulans SM-2001 containing
-1,3/1,6-glucan on formalin-induced chronic inflammation were observed. Doses of 62.5, 125, and 250 mg/kg of the exopolymers were orally administered once a day for 10 days to formalin-induced chronic inflammatory mice (0.02 ml of 3.75% formalin was subaponeurotically injected into the left hind paw), and then the bilateral hind-paw thickness and volume were measured daily, while the paw wet-weight, histological profiles, and histomorphometrical analyses were conducted at termination. The results were compared with those for diclofenac, indomethacin, and dexamethasone (intraperitoneally injected) 15 mg/kg-dosed groups. All the animals were sacrificed 10 days after dosing. As a result of the formalin injection, a marked increase in the difference between the intact and formalin-induced paw thickness and volume was detected in the formalin-injected control compared with that in the intact control with time, plus at the time of sacrifice, the difference in the paw wet-weights was also dramatically increased. In a histological and histomorphometrical analysis, severe histological profiles of chronic inflammation were detected in the formalin-injected control with a marked increase in the thickness of the skin of the dorsum pedis. However, these formalin-induced chronic inflammatory changes were significantly and dose-dependently decreased by the exopolymer treatment. In conclusion, the exopolymer treatment inhibited the chronic inflammatory response induced by formalin injection in the mice. However, somewhat low efficacies were detected compared with those for the diclofenac-, indomethacin-, and dexamethasone-treated groups.
Assessment of the Human Risk by an Intake of Ethyl Carbamate Present in Major Korean Fermented Foods
Noh, I-Woo ; Ha, Mi-Sun ; Han, Eun-Mee ; Jang, In-Sook ; An, Youn-Joo ; Ha, Sang-Do ; Park, Sang-Kyu ; Bae, Dong-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1961~1967
Levels of ethyl carbamate, a potential carcinogen produced naturally during fermentation, in major Korean fermented foods and alcoholic beverages were determined by GC/MS/SIM, and their average daily intake and excess cancer risk in Korean people were estimated. In GC/MS/SIM analysis n.d.-4.26, 1.40-58.90, n.d.-3.76, n.d.-1.87, and 0.40-10.07
g/kg of ethyl carbamate were detected in kimchi, soy sauces, fermented pastes, fermented dairy products, and alcoholic beverages, respectively. The average daily intake of ethyl carbamate and excess cancer risk through major Korean fermented foods and alcoholic beverage consumption were 6.0 ng/kg bw/day and
, respectively for the average Korean person aged 3-64 years, and were mainly contributed by Chinese cabbage kimchi, soy sauces, and Soju.
Enhancement of Sensitivity in Interferometric Biosensing by Using a New Biolinker and Prebinding Antibody
Park, Jae-Sook ; Lim, Sung-Hyun ; Sim, Sang-Jun ; Chae, Hee-Yeop ; Yoon, Hyun-C. ; Yang, Sang-Sik ; Kim, Byung-Woo ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1968~1976
Recombinant E. coli ACV 1003 (recA:: lacZ) was used to measure low concentrations of DNA-damaging chemicals, which produce
-galactosidase via an SOS regulon system. Very low
-galactosidase activities of less than 0.01 unit/ml,
-galactosidase produced through an SOS response corresponding to the 10 ng/ml (ppb) of DNA damaging chemicals in the environment, can be rapidly determined by using an alternative interferometric biosensor with optically flat thin films of porous silicon rather than by the conventional time-consuming Miller's enzyme assay as well as the ELISA method. fu order to enhance the sensitivity in the interferometry, it needs to obtain more uniform distribution and higher biolinking efficiency, whereas interferometric sensing is rapid, cheap, and advantageous in high throughput by using a multiple-well-type chip. In this study, pore size adjusted to 60 nm for the target enzyme
-galactosidase to be bound on both walls of a Si pore and a calyx crown derivative was apllied as a more efficient biolinker. Furthermore, anti-
-galactosidase was previously functionalized with the biolinker for the target
-galactosidase to be specifically bound. When anti-
-galactosidase was bound to the calyx-crown derivative-linked surface, the effective optical thickness was found to be three times as high as that obtained without using anti-
-galactosidase. The resolution obtained was very similar to that afforded by the time-consuming ELISA method; however, the reproducibility was still unsatisfactory, below 1 unit
-galactosidase/ml, owing to the microscopic non-uniform distribution of the pores in the etched silicon surface.
Tyrosinase Inhibitor from the Flowers of Impatiens balsamina
Lim, Young-Hee ; Kim, In-Hwan ; Seo, Jung-Ju ; Kim, Jeong-Keun ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1977~1983
Kaempferol was isolated and identified from the methanol extract of the flowers of Impatiens balsamina. Kaempferol showed inhibitory activity against mushroom tyrosinase with an
of 0.042 mM. Inhibition kinetics, as determined using a Lineweaver-Burk plot, showed kaempferol to be a competitive inhibitor of mushroom tyrosinase with a
value of 0.011 mM. The lag phase of tyrosine hydroxylation catalyzed by mushroom tyrosinase clearly increased on increasing the concentration of kaempferol. In addition to its tyrosinase inhibiting activity, kaempferol strongly inhibited melanin production by Streptomyces bikiniensis, in a dose-dependent manner, without inhibiting cell growth. For comparative purposes, the tyrosinase inhibitory activity of kaempferol was also assayed versus quercetin, a positive standard.
Antiprotozoal Activity of Deacetylated Chitosan Oligosaccharide (dp 2-8) on Trichomonas vaginalis
Shin, Woon-Seob ; Kil, Jun-Cheul ; Park, Gab-Man ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1984~1989
Deacetylated chitosan oligosaccharide (COS) had effective antiprotozoal activity against Trichomonas vaginalis (Minimal Inhibitory Concentration, MIC 0.25%), whereas 80% acetylated cas showed no antiprotozoal activity (MIC > 1 %). an the other hand, 80% acetylated cas showed growth stimulatory activity against the protozoa. When T. vaginalis was treated with 98% deacetylated COS at 0.25% concentration, the viability of the protozoa was rapidly decreased within 15 min, and the protozoa completely died within 40 min. Ultrastructural changes of trichomonads treated with COS included a loss of defined nuclear membrane and endoplasmic reticulum membranes, an increase in the number of free ribosome, vacuolation, and ultimately lysis of the cell membrane. These results indicate that deacetylated COS can be used as an antitrichomonal agent, although its lethal mechanism is not known.
Proteome Analysis of Waito-c Rice Seedlings Treated with Culture Fluid of Gibberellin-producing Fungus, Fusarium proliferatum KGL0401
Rim, Soon-Ok ; Lee, Jin-Hyung ; Hwang, Seon-Kap ; Suh, Seok-Jong ; Lee, Jin-Man ; Rhee, In-Koo ; Kim, Jong-Guk ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1990~1994
Fusarium proliferatum KGL0401 was previously isolated from Physalis alkekengi var. francheti plant roots and exhibited a high GA productivity. A gas chromatography-mass spectrometry (GC-MS) analysis of extracts of the culture fluid of F proliferatum KGL0401 also revealed the presence of
. Therefore, the present study conducted a proteome analysis of waito-c rice treated with the culture fluid of the isolated F proliferatum KGL0401 to identify the protein expression triggered by the GA-containing culture fluid. The results revealed the overexpression of 180 protein spots in the sample treated with the culture fluid. Among them, 75 induced proteins were selected and analyzed by MALDI-TOF (matrix-assisted laser desorption-iorrization time-of-flight) mass spectrometry, followed by database searching, and 51 proteins were identified.
Cloning of p-Hydroxybenzoate Degradation Genes and the Overexpression of Protocatechuate 4,5-Dioxygenase from Pseudomonas sp. K82
Yoon, Young-Ho ; Park, Soon-Ho ; Leem, Sun-Hee ; Kim, Seung-Il ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 1995~1999
Pseudomonas sp. K82 cultured in p-hydroxybenzoate induces protocatechuate 4,5-dioxygenase (PCD 4,5) for p-hydroxybenzoate degradation. In this study, a 6.0-kbp EcoR1 fragment containing p-hydroxybenzoate degradation genes was cloned from the genome of Pseudomonas sp. K82. Sequence analysis identified four genes, namely, pcaD, pcaA, pcaB, and pcaC genes known to be involved in p-hydroxybenzoate degradation. Two putative 4-hydroxyphenylpyruvate dioxygenases and one putative oxidoreductase were closely located by the p-hydroxybenzoate degradation genes. The gene arrangement and sequences of these p-hydroxybenzoate degradation genes were similar to those of Comamonas testosteroni and Pseudomonas ochraceae. PcaAB (PCD4,5) was overexpressed in the expression vector pGEX-4T-3, purified using a GST column, and confirmed to have protocatechuate 4,5-dioxygenase activity. The N-terminal amino acid sequences of overexpressed PCD4,5 were identical with those of purified PCD4,5 from Pseudomonas sp. K82.
Expression of Thermostable
-Glucosidase from Thermus caldophilus GK24 in Recombinant Saccharomyces cerevisiae
Choi, Jae-Youl ; Ahn, Jung-Oh ; Kim, Sun-Il ; Shin, Hyun-Jae ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 2000~2003
A gene (GenBank AF096282) coding for a
-glucosidase (TcaAG, EC 18.104.22.168) from Thermus caldophilus GK24 was expressed in Saccharomyces cerevisiae, a generally recognized as safe (GRAS) host. The thermostable
-glucosidase was produced inside of the GRAS host at 0.04 unit/mg-dry cell by the constitutively expressing ADH1 promoter and at 1.2 unit/mg-dry cell by the inductively expressing GALl0 promoter, respectively. No
-glucosidase activities were found in the medium when the MF-alpha signal sequence from S. cerevisiae or
-amylase signal sequence from Aspergillus oryzae were fused before the
-glucosidase gene for the secretion.
Effective Family Shuffling Method Using Complementary DNA Fragments Produced by S1 Nuclease
Hong, Soon-Gyu ;
Journal of Microbiology and Biotechnology, volume 16, issue 12, 2006, Pages 2004~2007
An efficient method for the in vitro reassembly of homologous DNA sequences is presented. The proposed method involves obtaining single strands of homologous genes and hybridizing them to obtain partially hybridized heteroduplex DNA; cleaving the single-stranded regions of the heteroduplex DNA using S1 nuclease to generate double-strand DNA fragments; denaturing the double-strand DNA fragments to generate single-strand DNA fragments; conducting a series of polymerase chain reactions (PCR) using the single-strand DNA fragments as internal primers and a mixture of homologous DNA as templates to obtain elongated reassembled DNA; and finally, amplifying the reassembled DNA by a PCR using terminal primers. As a result, DNA reassembly could be achieved between homologous genes with a sequence similarity as low as 78%.