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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 10, Issue 6 - Dec 2000
Volume 10, Issue 5 - Oct 2000
Volume 10, Issue 4 - Aug 2000
Volume 10, Issue 3 - Jun 2000
Volume 10, Issue 2 - Apr 2000
Volume 10, Issue 1 - Feb 2000
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Effect of Culture Conditions on the production of Succinate by Enterococcus faecalis RKY1
Kang, Kui-Hyun ; Yun, Jong-Sun ; Ryu, Hwa-Won ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 1~7
Bioconversion of fumarate to succinate was anaerobically conduced in a synthetic medium containing glycerol as a hydrogen donor and fumarate as a hydrogen acceptor. We investigated the effects of pH, carbon and nitrogen sources, conversion substrate, and other culture conditions on the production of succinate using a nwely isoloated Enterococcus facalis PKY1. Addition of a variety of carbonates to the medium significantly increasd the rates of production of succinate. The production of succinate and cell growth were relatively satisfactory in the pH range of 7.0-7.6. By using glycerol as a hydrogen donor, high purity succinate was produced with few byproducts. Yeast extract as a sole nitrogen source was the most effective for producing succinalte. As a result, the optimum condition of biconversion was obtained at a medium containing 20g/I glycerol, 50 g/l fumarate, 15 g/l yeast extract, 10 g/l
, 1 g/I NaCl, 50ppm
, and 5 g/I
at pH 7.0-7.6. Under the optimum condition, a succinate concentration of 153 g/I was produced in 36 h. The total volumetric production rate and the molar yield of succinate were 4.3 g/l/h and 85%, respectively.
IL-6 mRNA Expression in Mouse Peritoneal Macrophages and NIH3T3 Fibroblasts in Response to Candida albicans
Lee, Young-Sun ; Kim, Hee-Sun ; Kim, Sung-Kwang ; Kim, Sang-Dal ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 8~15
Despite extensive investigation, the mechanisms of immune responses to Candida albicans infection remain poorly understood. Using RT-PCR and Northern blot analysis, this study demonstrates the pattern of IL-6 mRNA expression in thioglycollate-elicited mouse peritoneal macrophages and NIH3T3 fibroblasts (NIH3T3) in response to C. albicans. The expression of IL-6 mRNA was detectable in both cell types. However, IL-10 mRNA was only expressed in the macrophages, and IL-4 mRNA was not expressed in neither of the two cell types. Although the phagocytic function of the macrophages was inhibited by Cytochalasin D, these macrophages could still induce the expression of IL-6mRNA. These findings indicated that the phagocytosis of C. albicans is not pivotal in the induction of IL-6 mRNA expression. A Northern blot analysis was used to investigate the dose effects of C. albicans and time-course kinetics of IL-6 mRNA expression at various time points. IL-6 mRNA was expressed in a dose-independent manner, and was detectable as early as 30min after C. albicans stimulation. It was evenly sustained up to 4h. These results can contribute to understanding the mechanism of IL-6 mRNA expression in macrophages and NIH3T3 cells in response to C, albicans.
Antitumor Activity of Paecilomyces japonica is Mediated by Apoptotic Cell Death
Park, Youn-Hee ; Moon, Eun-Kyung ; Shin, Yong-Kyu ; Bae, Myung-Ae ; Kim, Jong-Guk ; Kim, Young-Ho ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 16~20
The aqueous extract from the cultural mycelium of Paecilomyces japonica showed cytotoxicity against several tumor cells including Jurkat, U937, HL-60, HepG2, BW5147.G.1.4, and NIH3T3. When the aqueous extract was fractionated by sequential organic solvent extractions using n-hexane and ethyl acetate, the ethyl acetate fraction appeared to contain the most cytotoxic activity, and the
values for various tumor cells were in the range from 1.5 to
. To elucidate the cellular mechanism underlying the induced cytotoxicity, the apoptotic DNA fragmentation along with the cell cycle proression was examined in Jurkat T cells following the ethyl acetate fraction treatment. In the presence of
of the ethyl acetate fraction, apoptotic DNA fragmentation of the cells was detected within 1 h and increased upto 24 h in a time-dependent manner. Under the same conditions, a sub-G1 peak was detectable by flow cytometry. These results indicate that the cytotoxic effect of P. japonica on tumor cells is attributable to the induced apoptosis.
Development of DNA Chip Microarrayer
Yoon, Sung-Ho ; Choi, Jong-Gil ; Lee, Sang-Yup ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 21~26
A microarrayer system was developed mainly for manufacturing DNA chips. The 3-axis robot was designed to automatically collect samples from 96-or 384-well microtiter plates using up to 16 simultaneously moving pens and to deposit them on a surface-modified slide glass. This is followed by a wash/dry operation in a clean station. The cycle is repeated with a new set of samples, This system can deposit cDNA or oligonucleotides with spot intervals of
and the spot size of
, thus allowing a high density DNA chip containing about 5,000 spots per
. The entire procedure is controlled by the Visual C++ program that was written in our laboratory by using a personal computer with Pentium 100 CPU.
Induction of Apoptotic Cell Death in Human Jurkat T Cells by a Chlorophyll Derivative (Cp-D) Isolated from Actinidia arguta Planchon
Park, Youn-Hee ; Chun, En-Mi ; Bae, Myung-Ae ; Seu, Young-Bae ; Song, Kyung-Sik ; Kim, Young-Ho ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 27~34
The chloroform and methanol (2;1, v/v) extract from an edible plant, Actinidia arguta Planchon, appeared to possess antitumor activity against human leukemias Jurkat T and U937 cells through inducing apoptosis. The substance in the solvent extract was purified by silica gel column chromatography, preparative TLC, and Sephadex LH-20 column chromatography. Characteristics of the substance analyzed by UV scanning analysis,
NMR spectra suggested that the substance belongs to the chlorophyll derivatives-like group. The
value of the chlorophyll derivative (Cp-D) determined by MTT assay was
for U937, and
for HL-60m and was more toxic to these leukemias than to solid tumors or normal fibroblast. In order to elucidate cellular mechanisms underlying the cytotoxicity, the effect of the Cp-D on Jurkat T cells was investigated. When cells were treated with the Cp-D at a concentration of
, [3H]thymidine incorporation declined rapidly and wa undetectable in 1h. However, no significant changes were made in the cell cycle distribution of the cells by 24h. The sub-Gl peak representing apoptotic cells began to be detectable in 36h, at which time apoptotic DNA fragmentation was also detected on agarose gel electrophoresis, demonstrating that the cytotoxic effect of the Cp-D is attributable to the induced apoptosis. Under the same conditions, although the protein level of cyclin-dependent kinases such as cdc4, csk6, cdk2, and cdc2 was not significantly changed until 24h, the kinase activity of all c안 rapidly declined and reached a minimum level within 1-6h and then recovered to the initial level by 12h and sustained until 24h. These results suggest that inactivation of cdks at an inappropriate time during the cell cycle progression in jurkat T cells following a treatment with the Cp-D leads to induction of apoptotic cell death.
Reaction Characteristics of 4-Methylcatechol 2,3-Dioxygenase from Pseudomonas putida SU10
Ha, You-Mee ; Jung, Young-Hee ; Kwon, Dae-Young ; Kim, Young-Soo ; Kim, Chy-Kyung ; Min, Kyung-Hee ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 35~42
Reaction characteristics of 4-methylcatechol 2,3-dioxygenase (4MC230) purified from Pseudomonas putida SU10 with a higher activity toward 4-methylcatechol than catechol or 3-cethylcatechol were studied by altering their physical and chemical properties. The enzyme exhibited a maximum activity at pH 7.5 and approximately 40% at pH 6.0 for 4-methylcatechol hydrolysis. The optimum temperature for the enzyme was around
, since the enzyme was unstable at higher temperature. Acetone(10%) stabilized the 4MC230. The effects of solvent and other chemicals (inactivator or reactivator) for the reactivation of the 4MC230 were also investigated. Silver nitrate and hydrogen peroxid severely deactivated the enzyme and the deactivation by hydrogen peroxide severely deactivated the enzyme and the deactivation by hydrogen peroxide was mainly due to the oxidation of ferrous ion to ferric ion. Some solvents acted as an activator and protector for the enzyme from deactivation by hydrogen peroxide. Ascorbate, cysteine, or ferrous ion reactivated the deactivated enzyme by hydrogen peroxide. The addition of ferrous ion together with a reducing agent fully recovered the enzyme activity and increased its activity abut 2 times.
Changes of Physiological Activity of Mustard Leaf during Its Fermentation Period
Lim, Hyun-Soo ; Yoo, Eun-Jeong ; Choi, Myeong-Rak ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 43~47
In vitro cytotoxicity and antioxidative effects of water extracts prepared from Mustard Leaf Kimchi (MLK) during its fermentation period were investigated. The cytotoxicity against HepG2 (human hepatic cancer) by water extracts from the well fermented Mustard Leaf Kimchi was higher than others (fermented for 0 to 6 days at 18
), and IC50 of water extracts at the points of 6, 8, 10, and 14days during fermentation were 213.4, 99.2, 99.9, and 109.8
/ml, respectively. Antioxidative activity of water extracts from MLK during various fermentation periods was higher than that of blank distilled water. However, the antioxidative activity of well-fermented water extracts of MLK (fermented for 8-14 days) did not show any difference from that of others (fermented for 2-6 days). Thus, water extracts of well-fermented MLK (fermented during 8-14 days) significantly inhibited the growth of cancer cells in vitro, but little antioxidative activity was influenced by the various fermentation periods.
The Succinate : Quinone Oxidoreductase of Marine Bacterium Vibiro alginolyticus is a
Kim, Young-Jae ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 48~50
The energetics at the succinate:quinone oxidoreductase segment of V. alginolyticus was studied using a fluorescence quenching technique with inside-out membrane vesicles. A transient generation of the membrane potential (inside-positive) and
(inside-acidic) occurred in the presence of KCN and succinate when ubiquinone-1 (Q1) was added. The membrane potential (
) generated by the succinate; quinone oxidoreductase segment was completely collapsed by the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) and the membrane permeable anion
, whereas the
was completely collapsed by CCCP and
. From these results, it was concluded that the succinate: quinone oxidoreductase segment as well as quinol oxidase  in the respiratory chain of V. alginolyticus generated
Nitrogen-Dependent Regulation of Gluconic and/or Citric Acid Production by Aspergillus niger
Sankpal, Narenora V. ; Joshi, Arvino P. ; Kulkarni, Bhaskar D. ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 51~55
Surface culture fermentation using Aspergillus niger was studied for gluconic and citric acid production at different C/N ratios. A culture of A. niger was found to produce either gluconic acid alone, a mixture of gluconic and citric acid, or citric acid alone depending on the level of nitrogen in the medium (4 to 18mM). Glucose oxidase from the mycelial mat was also analyzed at different levels of nitrogen in the media. By choosing the level of nitrogen in the medium at the start of fermentation, it is possible to produce either of the two acids as the dominant product or the two together as a mixture.
Expression and Characterization of Helicobacter pylori Adhesin Protein Linked to Cholera Toxin A2/B Subunits in Escherichia coli
Kim, Byung-Oh ; Shin, Sung-Seup ; Yoo, Young-Hyo ; Pyo, Shuk-Neung ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 56~62
The hpa gene genetically linked to the ctxa2b gene was cloned into the pTED expression vector, and the constructed pTEDhpa/ctxa2b was transformed into Excherichia coli. The fusion protein, the adhesin fused to the cholera toxin subunit A2B (CTXA2B) subunit, was expressed to high levels as inclusion bodies in E. coli. The expressed protein was partially purified by washing the inclusion bodies with working solution containing 8M Urea and 0.1M DTT. Refolding of denatured fusion protein was carried out in the presence of glutathione redox buffer. The refolded fusion protein was purified by size exclusion chromatography. The expressed fusion protein was verified by SDS-PAGE, western blotting with antibodies to both antigenic components of adhesin and cholera toxin subunit B (CTXB), and its N-terminal amino acid sequence was analyzed. The orderly assembled fusion protein was confirmed by modified Gm1-ganglioside ELISA with Abs to adhesin. The results indicate that the purified fusion protein is an Adhesin/CTXA2B protein containing the H. pylori adhesin and
-ganglioside binding activity of CTXB and the expressed fusion protein in E. coli could be easily purified by the refolding process, Its molecular weight was 168kDa as estimated by size exclusion chromatography. The Adhesin/CTXA2B protein may be used as a candidate antigen for oral immunization against H. pylori.
Stress Responses of the Escherichia coli groE Promoter
Kwak, Young-Hak ; Kim, Sung-Jo ; Lee, Ki-Young ; Kim, Han-Bok ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 63~68
GroEL is well known as a molecular chaperone. In order to determine the dynamic stress response of the Escherichia coli groE promoter, a groE-lacZ operon fusion in the chromosome was constructed. Stress leading to
synthesis induces transcription from E. coli groE promoter, since the promoter is
. When the strain was stressed with ethanol, phenol, and sodium chloride, clear inductions of
were observed. Two types of simultaneous stresses of sodium chloride and phenol induced the enze much more than either of the two alone, suggesting that stress was an additive. The combined stress resulted in the highest induction of the enzyme in this system. The groE-lacZ fusion strain developed in this study can conveniently be used to detect other harmful pollutants in the environment. Stress treatment of cells containing recombinant proteins, which need GroEl, by ethanol, phenol, or sodium chloride, might have a tendency to increase their biological activities.
Optimization of Culture Conditions for Erythritol Production by Torula sp.
Kim, Kyung-Ah ; Noh, Bohg-Soo ; Lee, Jung-Kul ; Kim, Sang-Yong ; Park, Yong-Cheol ; Oh, Deok-Kun ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 69~74
The medium for erythritol production by Torula sp. in a 500-ml baffled flask was optimized to be 300 g/I sucrose, 10 g/I yeast extract, 3 g/I
, and 10 mg/I
with initial pH of 5.5. Using this optimal medium, erythritol of 166 g/I was obtained after 140 h of cultivation, corresponding to 55.3% of the erythritol yield from sucrose with a productivity of 1.11 g/I/h. Optimal concentrations of carbbon and nitrogen sources in a fermentor were higher than that in a flask due to the higher oxygen supply of the fermentor. Employing the medium containing 300 g/I or 400 g/I sucrose for the determination of optimal C/N ratio, the C/N ratio was found to be more important than the nitrogen concentration for effective erythritol production, The optimal ratio of yeast extract to sucrose (g/g) was 20. The yield and productivity of erythritol were maximal in the medium containing 400 g/I sucrose and 20 g/I yeast extract. when dissolved oxygen in the culture was increased, the cell mass increased but the erythritol production was manimal in the range of 5 to 10% of dissolved oxygen. Under the optimal the rane of 5 to 10% of dissolved oxygen. Under the optimal culture condition of the fermentor, a final erythritol concentration of 200 gI was obtained after 120 h with a yield of 50% and the productivity was 1.67 g/I/h. The yield was the highest among erythritol-producting microorganisms
Improved Refolding of Recombinant Human Proinsulin from Escherichia coli in a Two-stage Reactor System
Phue, Je-Nie ; Oh, Sung-Jin ; Son, Young-Jin ; Kim, Yong-In ; Kim, Kyung-Hwan ; Kim, Jung-Woo ; Hong, Chung-Il ; Chung, In-Sik ; Hahn, Tae-Ryong ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 75~80
An improved method of refolding recombinant human proinsulin from E. coli was presented. It was based on a two-stage stirred tank reactor in which denatured proinsulin-s-sulfonate was mixed instantaneously with a reaction buffer in the first stage reactor, and then fed to the second stage reactor. The mixture was stirred further for a total of 30h in the second stage reactor. In this system, unfavorable effects present due to the increase in reaction volume and protein concentration for protein refolding, which becomes significant in a large-scale operation, were avoided. Refolding yields of over 80% was obtained for achieving reaction volume of upto 50 l at protein concentration of 1 mg/ml. The optimum urea concentration was 1M. Refolding yield at the 1-1 reaction volume and protein concentration of 0.5mg/ml was increased about 2.5-fold, compared to that in a batch reactor. By increasing protein concentration in a two-stage refolding reaction, the cost for insulin production could be reduced, therefore, making this process economical.
Characterization of an Elastase Inhibitor Produced by Streptomyces lavendulae SMF11
Lee, Hyun-Sook ; Jin, Wook ; Kang, Sung-Gyun ; Hwang, Yoon-Sook ; Kho, Yung-Hee ; Lee, Kye-Joon ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 81~85
An elastase inhibitor, SMFEI02, was isolated from culture broth of Streptomyces lavendulae SMF11. The inhibitor was purified by ultrafiltration followed by XAD-7 column and Dowex-1 anion-exchange chromatographies, and preparative HPLC. The molecular formula was determined to be
(MW244) by HRFAB-MS analysis. The inhibitor was identified to be a diketopiperazine cyclo(S-Phe-S-Pro) by the optical rotation value and MNR spectral data, and showed inhibitory activities for trypsin, chymotrypsin, cathepsin B, and papain as well as elastase with the Ki values ranging from 1.78mM to
. The inhibition showed a competitive mode for elastase, chymotrypsin, and cathepsin B, whereas it showed a noncompetitive mode for trypsin and papain.
Cloning, Sequencing, and Characterization of Enterotoxin Pathogenicity Islet from Bacteroides fragilis 419
Rhie, Gi-Eun ; Chung, Gyung-Tae ; Lee, Yong-Jin ; Sung, Won-Keun ; Oh, Hee-Bok ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 86~90
We have earlier reported on the cloning and identification of bft-k from an enterotoxigenic strain of Bacteroides fragilis 419, which was isolated from the blood of a Korean patient who suffered from systemic infections [4,5]. The bft-k gene encodes a 397-amino-acids metalloprotease enterotoxin, and the protein has been identified as a new isoform of B. fragilis enterotoxins (BFTs), which are cytopathic to intestinal epithelial cells to induce fluid secretion and tissue damage in ligated intestinal loops [4, 6, 18, 20]. This report describes the cloning and sequencing of the enterotoxin pahogenicity islet of B. fragilis 419 which contains the bft-k gene. the cloned enterotoxin pathogenicity islet was found to have 6,045 bp in length and to contain 120bp direct repeats near its end. In the pathogenicity islet, in addition to the BFR-K, two putative open reading frames (ORFs) were identified; (1) the t-3 gene encoding a 396-amino-acids protein of a putative metalloprotease; (2) the third gene encoding an ORF of a 59-amino-acids protein, whose function has not yet beenn characterized. The expression of the t-3 gene in B. fragilis 419 was verified by western blot analysis.
Expression of Modified Green Fluorescent Protein in Suspension Culture of Taxus cuspidata
Kim, Chang-Heon ; Kim, Kyung-Il ; Chung, In-Sik ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 91~94
The suspension cells of Taxus cuspidata were transformed with Agrobacterium tumefaciens harboring binary vector pCAMBIE1302 encoding mgfp. Transient transfection efficiency was compared by using the fluoremetric measurement. The transient transfection efficiency was improved by transformation with DMSO and/or sonication treatment. Optimum conditions for DMSO and sonication treatment were 3% and 30sec, respectively. selection and maintenance of transformed cells were continued for 3 months. An insertion of the mgfp gene in transformed cells was detected by PCR and an expression of GFP confirmed by the western blot analysis.
Immunochemical Studies on Expression of Quinoproteins in Escherichia coli
Ryou, Chong-Suk ; Kim, Jae-Beom ; Kwon, Moo-Sik ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 95~98
An immunochemical method has been develooped as the most sensitive tool for studying the expression of quinoproteins containing pyrroloquinoline qinone(PQQ) in E. coli. The PQQ was conjugated to bovine serum albumin (BSA), and the conjugant was purified by using a
dextran desalting column chromatography. The PQQ-BSA conjugant was immunized to rabbits, and the IgG fractions of the antisera were purified. The most sensitive antibody against PQQ-BSA conjugant recognized some nanogram quantity of the antigen on the blot, but had little cross reactivity with BSA. Using this batch of the antibody, all the immunochemical assays of quinoproteins in E. coli were preformed. Some six different PQQ-specfic spots were detected by Western blot analysis of the soluble proteins in E. coli were performed. Some six different PQQ-specific spots were detected by Western blot analysis of the soluble proteins in E. coli after two-dimensional gel electrophoresis. Their molecular weights on the blot were estimated to be about 100-, 90-, 72-, 58-, 52-, and 50kDa. Their pI values fell in the range from 4.8 to 5.5. These results stronly suggest that quinoproteins are present in E. coli, and that the protein moieties were covalently bound to PQQ.
Dependency of Water Availability on the Esterifying Activity of Candida cylindracea Lipase in Organic Solvent
Moor, Izani ; Noor, Jamil ; Ibrahim che Omar ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 99~102
To establish optimal conditions for esterification by Candida cylindracea, lipase reactions were performed simultaneously, separately, or individually in the varying initial rates of
mole free fatty acids consumed min-1g-1. The reactants which were conditioned at aw of 0.12 gave the highest initial rate of esterifying
mole free fatty acids consumed min-1g-1. These results suggest that the esterifying activity of lipase in an organic system depends on the transfer of available water within the reaction system.
Influence of Temperature, Oxygen, m-Chlorophenylhydrazone Cerulenin, and Quinacrine on the Production of Extracellular Proteases in Bacillus cereus
Kim, Sam-Sun ; Park, Yong-Ha ; Rhee, In-Koo ; Kim, Young-Jae ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 103~106
Bacillus cereus KCTC 3674 excretes at least two kinds of extracellular proteases into the growth medium. Two major bands of the protease activity with molecular weights of approximately 100 and 38 kDa were obtained after gelatin-SDS-PAGE. The protease with a molecular weight of 38kDa was identified as an extracellular neutral (metallo-) protease. The neutral protease was quite thermostabile but labile to alkaline pH. On the contrary, the 100-kDa protease was thermolabile but stable to alkaline pH. The production of 38-kDa neutral protease was strongly affected by temperature, oxygen, carbonylcyanied m-chlorophenylhydrazone(CCCP) that was defined as a protonophofre, and cerulenin which inhibited lipid synthesis and caused changes in the membrane composition. On the other hand, the production of the 100-kDa protease was strongly affected by only temperature and cerulenin. Quinacrine (0.2 mM), which inhibits the penicillinase-releasing proteases of Bacillus licheniformis, had no effect, whatsoever, on the production of extracellular proteases in B.cereus KCTC 3674.
Re-Elicitation with Methyl Jasmonate in Eschscholtzia californica Cell Suspension Cultures
Byun, Sang-Yo ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 107~110
Elicited cells with methyl jasmonate continued to produce benzophenanthridine alkaloids throughout medium changes in suspension cultures of Eschscholtzia californica. Large increases in alkaloid production were observed by re-elitations with medium changes. The total alkaloid production increased during the successive elicitation steps reaching a maximum level on the 4th elicitation. The highest total alkaloid produced was 250 mg/I, which was 20fold higher than that of the single elicitation and 4-fold higher than that of the normal culture without elicitation. The large increases in alkaloid production in successive re-elicitations with medium changes are believed to be caused by the accumulation of the signal transduction compound, jasmonate.
Characterization of Benzoate Degradation via ortho-Cleavage by Streptomyces setonii
An, Hae-Reun ; Park, Hyun-Joo ; Kim, Eung-Soo ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 111~114
Streptomyces are widespread in nature and play a very important role in the biosynthesis as well as biodegradation of natural and unnatural aromatic compounds. Both qualitatively and quantitatively through TLC and UV spectrophotometric assays, it was observed that the thermophilic soil bacteria S. setonii (ATCC 39116), which can utilize a benzoate as a sole carbon and energy source in a minimal liquid culture, was not very sensitive to the benzoate concentation and to the culture conditions such as the pH and temperature. The in vitro conversion of a catechol to a cis, cis-muconic acid by a crude S. setonii lysate implies that the aromatic ring cleavage by S. setonii is initiated by a thermostable catechol-1,2-dioxygenase, the key enzyme in the ortho-cleavage pathway of aromatic compound biodegradation. Unlike non-degrading S. lividans, S.setonii was also highly resistant to other similar hazardous aromatic compounds, exhibiting almost no adverse effect on its growth in a complex liquid culture.
Expression of Enhanced Green Fluorescent Protein from Stably Transformed Drosophila melanogaster S2 Cells
Lee, Jong-Min ; Park, Jong-Hwa ; Chung, In-Sik ;
Journal of Microbiology and Biotechnology, volume 10, issue 1, 2000, Pages 115~118
Recombinant plasmids harboring a heterologous gene coding for the enhanced green fluorescent protein (EGFP) were transfected and expressed in Drosophila melanogaster S2 cells. A stable transformation of polyclonal cell populations expressing EGFP were isolated after 4 weeks of selection with hygromycin B. The recombinant EFGP expressed in transformed S2 cells consisted of a molecular weight of 27 kDa. EGFP expression was also confirmed by fluorometric measurement. The maximum EGFP concentration was about 9.3 mg/I. The present findings demonstrate not only the successful stable expression of EGFP in Drosophuila was about 9.3 mgI. The present findings demonstrate not only the successful stable expression of EGFP in Drosophila S2 cells, but also the use of EGFP as a reporter to analyze gene expression, with its potential of a Drosophila cell expression system for recombinant protein production being an alternative to a baculovirus-insect cell expression system.