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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 8, Issue 6 - Dec 1998
Volume 8, Issue 5 - Oct 1998
Volume 8, Issue 4 - Aug 1998
Volume 8, Issue 3 - Jun 1998
Volume 8, Issue 2 - Apr 1998
Volume 8, Issue 1 - Feb 1998
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Dynamics of Morphological and Physiological Differentiation in the Actinomycetes Group and Quantitative Analysis of the Differentiations
Lee, Kye-Joon ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 1~7
Controlling Mammalian Cell Metabolism in Bioreactors
Hu, Wei-Shou ; Weichang, Zhou ; Lilith F. Europa ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 8~13
Animal cells in culture typically convert most of the glucose they consume into lactate. The accumulation of lactate, however, is commonly cited as one of the factors that inhibit cell growth and limit the maximum cell concentration that can be achieved in culture. The specific production of lactate and the amount of glucose converted to lactate can be reduced when cells are grown in a fed-batch culture in which the residual glucose concentration is maintained at low levels. Such a fed-batch culture was used to grow and adapt hybridoma cells into a low-lactate-producing state before changing into continuous culture. The cells reached and maintained a high viable cell concentration at steady state. In a similar manner, cells that were initially grown in batch culture and a glucose-rich environment reached a steady state with a cell concentration that is much lower. The feed composition and dilution rates for both cultures were similar, suggesting steady state multiplicity. From a processing perspective the desired steady state among those is the one with the least metabolite production. At such seady state nutrient concentration in the feed can be further increased to increase cell and product concentrations without causing the metabolite inhibitory effect typically seen in a cell culture. Controlling cell metabolism in a continuous culture to reduce or eliminate waste metabolite production may significantly improve the productivity of mammalian cell culture processes.
-Xylosidase (XylA) Synthesis in Bacillus stearothermophilus
Cho, Ssang-Goo ; Choi, Yong-Jin ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 14~20
Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases,
-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of
-xylosidase at the highest level while xylose gave about 30% of the
-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and
-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major
-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.
Catabolite Repression of the Bacillus stearothermophilus
-Xylosidase Gene (xylA) in Bacillus subtilis
Cho, Ssang-Goo ; Choi, Yong-Jin ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 21~27
The xylA gene of Bacillus stearothermophilus encoding the major
-xylosidase was previously cloned and sequenced. In the present study we examined the regulation of the cloned xylA gene expression in Bauillus subtilis MW15 carrying the xylA::aprA fusion plasmids. The induction of the fused xylA gene expression remained uninfluenced by any of the carbon sources tested but the gene expression was repressed about 2-3 fold in the presence of glucose. Two CRE-like sequences (CRE-1: nucleotides ＋ 124 to ＋136 and CRE-2: ＋247 to ＋259) were recognized within the reading frame region of the xylA gene. The deletion experiments showed that the CRE-2 sequence had a role in catabolite repression (CR) as a true CRE of the xylA gene, but the CRE-1 had no effect on CR of the xylA gene expression. Surprisingly, the deletion of the CRE- 1 sequence reduced about 2~3 fold of the expression of the xylA fused gene. The repression ratios of the xylA gene expression were estimated to be about 0.4 from the assay of subtilisin activity, and about 0.3 at the level of transcription by determining the amounts of xylA transcripts in B. subtilis. While, the level of CR of the xylA gene was assessed to be about l0-fold in previous work when the relative amounts of the xylA transcripts were measured in B. stearothermophilus.
Molecular Cloning and the Nucleotide Sequence of a Bacillus sp. KK-l
Chun, Yong-Chin ; Jung, Kyung-Hwa ; Lee, Jae-Chan ; Park, Seung-Hwan ; Chung, Ho-Kwon ; Yoon, Ki-Hong ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 28~33
A gene coding for
-xylosidase from thermophilic xylanolytic Bacillus sp. KK-1 was cloned into Escherichia coli using plasmid pBR322. Recombinant plasmid DNAs were isloated from E. coli clones which were capable of hydrolyzing 4-methylumbelliferyl-
-D xylopyranoside. Restriction analysis showed the DNAs to share a common insert DNA. Xylo-oligosaccharides, including xylotriose, xylotetraose, xylopentaose, and xylobiose were hydrolyzed to form xylose as an end product by cell-free extracts of the E. coli clones, confirming that the cloned gene from strain KK-1 is
-xylosidase gene. The
-xylosidase gene of strain KK-1 designated as xylB was completely sequenced. The xylB gene consisted of an open reading frame of 1,602 nucleotides encoding a polypeptide of 533 amino acid residues, and a TGA stop codon. The 3' flanking region contained one stem-loop structure which may be involved in transcriptional termination. The deduced amino acid sequence of the KK-1
-xylosidase was highly homologous to the
-xylosidases of Bacillus subtilis and Bacillus pumilus, but it showed no similarity to a thermostable
-xylosidase from Bacillus stearothermophilus.
Expression of an Antimicrobial Peptide Magainin by a Promoter Inversion System
Lee, Jae-Hyun ; Hong, Seung-Suh ; Kim, Sun-Chang ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 34~41
A method was developed for the controlled expression of an antimicrobial peptide magainin in Escherichia coli. A series of concatemeric magainin genes was constructed with a gene amplification vector, and fused to the 3'end of malE gene encoding the affinity ligand, E. coli maltose-binding protein (MBP). The construct directed the synthesis of the fusion protein with the magainin polypeptide fused to the C-terminus of MBP. The fusion protein was expressed in a tightly regulatable expression system which was under the control of an invertible promoter. The MBP-fused magainin monomer was expressed efficiently. However, the expression level of the MBP-fused magainin in E. coli decreased with the increasing size of multimers possibly because of the transcription and translation inhibition by the multimeric peptides. After purification using an amylose affinity column, the fusion protein was digested by factor Xa at a specific cleavage site between the monomers. The recombinant magainin had an antimicrobial activity identical to that of synthetic magainin. This experiment shows that a biologically active, antimicrobial peptide magainin can be produced by fusing to MBP, along with a promoter inversion vector system.
Expression and Secretion of Human Serum Albumin in the Yeast Saccharomyces cerevisae
Kang, Hyun-Ah ; Jung, Moon-Soo ; Hong, Won-Kyoung ; Sohn, Jung-Hoon ; Choi, Eui-Sung ; Rhee, Sang-Ki ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 42~48
In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.
Identification of Multiple Active Forms in Cellulase-xylanase of Aspergillus sp. 8-17 by Active Staining
Shin, Pyung-Gyun ; Ahn, Jun-Bae ; Kim, Chang-Young ; Jeong, Won-Hwa ; Ryu, Jin-Chang ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 49~52
A fungal strain able to produce filter paper activity (FPase) was isolated from soil by testing the ability to hydrolyze using filter paper. The isolated strain was identified as an Aspergilus sp. judging from its morphological and microscopical characteristics. The cellulase-xylanase system of Aspergillus sp. 8-17 was detected in situ after gel electrophoresis in the presence of SDS and showed that each protein pattern had a distinct polypeptide composition.
-1,4-Glucanase, cellobiohydrolase, and xylanase activity profiles differ from protein patterns. The Aspergillus sp. 8-17 hydrolytic enzymes responsible for the hydrolysis of
-glucan, MUC, and xylan have multiple active forms.
Evaluation of Metal Biosorption Efficiency of Laboratory-grown Microcystis under Various Environmental Conditions
Pradhan, Subhashree ; Singh, Sarita ; Rai, Lal Chand ; Parker, Dorothy L. ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 53~60
This study examines the effect of pH, temperature, metal ion concentration and culture density on metal biosorption by the nuisance cyanobacterium Microcystis aeruginosa. Ni biosorption was higher at pH 9.2 than at neutral and acidic pH. In contrast the biosorption of Cu and Zn was maximum at pH 7.0. However, biosorption of Zn was difficult to measure at pH values 9.2 and 10.5, owing to the formation of insoluble complexes. All the test metals (Cu, Zn, and Ni) showed maximum biosorption rate at low culture densities of 40 mg dry wt
. The biosorption of Cu, Zn, and Ni was maximum at
. However, no worthwhile difference in Zn and Ni sorption was noticed at 4 and
as compared to
. Of these three metals used Microcystis showed a greater binding capacity (
value=0.84, Freundlich adsorbent capacity) and accelerated biosorption rate for Cu under various environmental conditions. Fitness of mathematical models on metal biosorption by Microcystis confirmed that the biological materials behave in the same way as physical materials. These results suggest that before using a biosorbent for metal recovery, the environmental requirements of the biosorbent must be ascertained.
Biodegradation of Phenol by a Trichloroethylene-cometabolizing Bacterium
Park, Geun-Tae ; Son, Hong-Joo ; Kim, Jong-Goo ; Lee, Sang-Joon ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 61~66
A microorganism which degrades phenol and co-metabolizes trichloroethylene (TCE) was isolated from Yangsan stream after enrichment in a medium containing phenol as the sole carbon source. The isolate EL-43P was identified as the genus Rhodococcus by its morphological, cultural and physiological characteristics. Phenol-induced cells of Rhodococcus sp. EL-43P degraded TCE. Toluene and nutrient broth could not replace the phenol requirement. The optimal conditions of initial pH and temperature of media for growth were 7.0~9.0 and
, respectively. Rhodococcus sp. EL-43P could grow with phenol up to 1,000 ppm. Growth was inhibited by phenol at a concentration above 1,500 ppm. It was observed that Rhodococcus sp. EL-43P was able to degrade 90% of phenol (1,000 ppm) after 40 h in a culture. Phenol-induced cells of Rhodococcus sp. EL-43P degraded 95% of
TCE in 6 h. Rhodococcus sp. EL-43P hardly degraded TCE above
Taxonomic Studies of the Beta Hemolysis-causing Pathogen Bacillus cereus Isolated from Sea Water
Kim, Sam-Sun ; Park, Yong-Ha ; Lee, Jung-Sook ; Yoon, Jung-Hoon ; Shin, Yong-Kook ; Rhee, In-Koo ; Kim, Young-Jae ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 67~73
A bacterial strain that excretes hemolysins and proteases into the growth medium was isolated from sea water and designated as KYJ 961. A nearly complete nucleotide sequence of a 16S ribosomal RNA gene from the isolate was determined following the isolation and cloning of amplified genes. On the basis of the 16S ribosomal DNA sequence data, and morphological, chemotaxonomic, and physiological characteristics, strain KYJ 961 was classified as a strain of Bacillus cereus.
Characteristics of the Conditioned Medium Produced by CA-12 Lymph Node Stromal Cells
Lee, Sang-Han ; Lee, Dong-Sun ; Seu, Young-Bae ; Kim, Jong-Guk ; Tsuruo, Takashi ; Hong, Soon-Duck ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 74~80
CS-2l lymphoma cells that preferentially metastasize to lymph nodes after s.c. inoculation into BALB/c mice were grown in vitro in the presence of CA- 12 stromal cells isolated from lymph nodes. In order to obtain fundamental data on the identification and characterization of the soluble factors produced by CA-12 stromal cells, the conditioned medium of CA-12 stromal cells that inhibited apoptosis of CS-21 cells was examined. Various analytical treatments revealed that the soluble factors in CA-12 conditioned medium are very sensitive to heat treatment and trypsinization. Moreover CA-12 conditioned medium has an affinity with heparin but not with Con-A. In addition to these, the activity of CA-12 conditioned medium was blocked by H-7, a PKC inhibitor, but the conditioned medium could not induce the differentiation of thymocytes. We concluded that CA-12 conditioned medium contains stromal cell-derived apoptosis-inhibitory molecules that play an important role in proliferation of CS-2l cells by suppressing cell apoptosis.
Taguchi's Robust Design Method for Optimization of Lysophosphatidic Acid Production in an Open Reactor System
Han, Jeong-Jun ; Rhee, Joon-Shick ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 81~88
The determination of appropriate parameters and parameter conditions is very important for the optimization of production of target materials. Taguchi's method has been used widely as the basis for development trials and optimization during industrial process design. Reaction variables which influence product yield are easily determined and their effects are revealed by just a few reactions, negating the need for extensive experimental investigation. There are usually some factors that are responsible for variations in process characteristics, so called noise factors. Controlling noise factors is very costly and difficult or impossible. Taguchi's experimental design method was examined to determine the control factor's level that is less sensitive to the changes in environmental conditions and other noise factors without control of noise factors. In this study, optimization of lipase-catalyzed production of lysophosphatidic acid (LPA) which has various physiological functions was performed by Taguchi's method. We obtained LPA yields (
) with low variance (5.32) at 400 RPM, molar ratio of 40 : 3 (mol) (fatty acid: G-3-P), 48 h, and
. Thus, bioactive LPA with a desired fatty acid moiety could be produced with high yields and low variance despite various environmental noise factors.
Inhibition of DNA Topoisomerase I by Cryptotanshinone from Salvia miltiorrhiza
Lee, Dong-Sun ; Hong, Soon-Duck ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 89~91
Cryptotanshinone induced topoisomerase I-mediated DNA cleavage in vitro as strongly as camptothecin, whereas topoisomerase II-mediated DNA cleavage was not induced by this agent. In DNA relaxation assay using calf thymus DNA topoisomerase I and supercoiled pBR322 DNA, cryptotanshinone inhibited topoisomerase I-mediated DNA relaxation in a dose-dependent manner. In unwinding assay, cryptotanshinone (
) did not shift the topoisomers of DNA. These results suggest that cryptotanshinone exerted a preferential inhibition of topoisomerase I without intercalating into DNA.
Overexpression of Escherichia coli Thiol Peroxidase in the Periplasmic Space
Kim, Sung-Jin ; Cha, Mee-Kyung ; Kim, Il-Han ; Kim, Ha-Kun ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 92~95
Overproduction of Escherichia coli thiol peroxidase in the periplasmic space was achieved by locating the appropriate gene on a downstream region of the strong T7 promoter. E. coli strain BL21 carrying the recombinant plasmid pSK-TPX was induced by IPTG, lysed, and analyzed by SDS-polyacrylamide gel electrophoresis. A large amount of the overexpressed thiol peroxidase was located in the periplasmic space. A homogeneous thiol peroxidase was obtained from E. coli osmotic shock fluid by simple one-step gel permeation chromatography.
A Pathway for 4-Chlorobenzoate Degradation by Pseudomonas sp. S-47
Seo, Dong-In ; Chae, Jong-Chan ; Kim, Ki-Pil ; Kim, Young-Soo ; Lee, Ki-Sung ; Kim, Chi-Kyung ;
Journal of Microbiology and Biotechnology, volume 8, issue 1, 1998, Pages 96~100
Pseudomonas sp. S-47 degraded 4-chlorobenzoate (4CBA) to 4-chlorocatechol (4CC) that was subsequently ring-cleaved to form 5-chloro-2-hydroxymuconic semialdehyde. These intermediate compounds were identified by GC-mass spectrometry and UV-visible spectrophotometry. 5-chloro-2-hydroxymuconic acid converted from 5-chloro-2- hydroxymuconic semialdehyde (5C-2HMS) was dechlorinated to produce 2-hydroxypenta-2,4-dienoic acid (2HP-2,4DA) by the strain. These results indicate that Pseudomonas sp. S-47 degrades 4CBA to 2HP-2,4DA via a novel pathway including the meta-cleavage of 4CC and dechlorination of 5C-2HMS.