• Archives of Pharmacal Research
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• v.13 no.1
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• pp.5-8
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• 1990

The cycloaddition of the newely synthesized 5-(2-thienyl)methylene derivatives of thiazolidinone-4-thiones, 2a-c to acrylonitrile (3a), ethylacrylate (3b), N-phenylmaleimide (6) and dimethyl fumarate (8) has been evaluated. Under thermal reaction conditions [4 +2] cycloaddition proceeds with complete site and regioselectivity to yield the cycloadduct, 4, 5, 7 and 9, respectively. The antimicrobial activities of some of the new products were tested.

• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.55-63
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• 1985

Phosphate, ammonia, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate were examined for their ability to control the heat-stable enterotoxin (ST) production in succinate salts medium or in M9 medium. The results obtained were summerized as follows. 1. When the initial phosphate concentration was adjusted to 1.0mM, ST production was decreased to 80u/ml or less. But when the initial phosphate concentration was adjusted to 64mM or 100mM, enterotoxin production was 320u/ml. 2. When the initial ammonia concentration in the medium was adjusted to 1.0mM, no ST production and cell growth were observed. But when ammonia concentration was adjusted to 10mM, 19mM, 38mM or 76mM, enterotoxin production was 320u/ml. 3. Among carbon sources, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate, acetate supported the highest specific production (928 unit/O.D.) of heat-stable enterotoxin. From this results, we could assume that heat-stable enterotoxin production is controlled by stringent control mechanism. 4. When the pH of the succinate salts medium was kept between 6.2 to 6.5, no heat-stable enterotoxin production was observed, but when the pH of the medium was kept between pH 6.2 to 6.5, 267 unit/O.D. of heat-stable enterotoxin was produced. 5. Glucose inhibited the heat-stable enterotoxin production and the mechanism was assumed due to its capacity to lower the pH of the medium during catabolysis and its high metabolic energy.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.77-82
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• 2004

Quantifying rates of microbial processes under subsurface conditions is difficult, and is most commonly approximated by laboratory studies using aquifer materials. In this study a single-well, 'push-pull' test method is adapted for the in situ determination of denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests at an experimental well field of Korea University. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifyinc microorganisms. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate '||'&'||'gt; nitrite '||'&'||'gt; nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibi1ity assessments for in situ denitrification in nitrate-contaminated aquifers.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.201-209
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• 1989

Using Mu dJ(Km lac) operon fusion, several oxygen-regulated genetic loci were identified in Salmonella typhimurium. Nine aerobically inducible(oxi) and thirteen anaerobically inducible(ani) operon fusions were newly identified. Based on the control by oxrA regulatory locus, the ani-lacZ fusions were grouped into two classes: class I loci were regulated by oxrA regulatory locus; class II genes were not affected by this locus. Some of the ani-lacZ fusions had required growth in CAA and LB before they exhibited the inducible phinotype. Most of all ani-lacZ fusions were repressed by nitrate and fumarate. Three of the ani loci were mapped into $59{\pm}0.14$ map unit (YK114), $64{\pm}0.5$ map unit(YK120), and $93{\pm}0.29$ map unit(YK112) by testing the cotransduction frequency, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.175-178
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• 2004

Little study has been published specifically addressing the dynamics of nitrate reducing bacteria (NBR) during the bioremediation of nitrate-contaminated aquifer. In our previous study we successfully quantified fumarate-enhanced microbial nitrate reduction rate in a nitrate-contaminated aquifer by using a series of single-well push-pull tests (PPTs). In this study we analyzed the suspended population during PPTs. To monitor changes in the microbial community, PCR amplification of 16S rDNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. Before the stimulation of NBR, the dominant DGGE bands obtained by PCR were affiliated with V-Proteobacteria consisting of Acinetobacter spp. and Pseudomonas fluorescens. However, as NBR biostimulation proceeded, the dominant patterns of DGGE bands changed, and they were affiliated with Azoarcus denitrificans Td-3 and Flavobacterium xanthum. Azoarcus denitrificans Td-3 is known to completely reduce nitrate to nitrogen gas. The series of single-well push-pull tests in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ denitrification and provide important information about which microorganisms play a key role in bioremediation of a nitrate contaminated aquifer.

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.57-64
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• 2008

The fsrA gene in Bacillus subtilis has an analogous role of ryhB in E. coli and is controlled under fur, the iron regulator gene. At high concentration of iron the transcription of ryhB is repressed by fur and ryhB is transcribed under low concentration of iron. To spare iron produced ryhB small RNA represses the expression of sdhCDAB (succinate dehydrogenase). This study shows the growth rate of Bacillus subtilis strain of fur and fur/fsrA deletion mutants using organic acids of TCA cycle as carbon source. Mutant strain of fur does not grow well with succinate carbon source, but further deletion of fsrA regain to the growth of wild type strain. Also, nearly same results were observed with citrate and fumarate. These results are consistent to those of E. coli system. But fur and fur/fsrA deletion mutants grow well as much as the growth of wild type with malate carbon source. These results showed that upstream genes of succinate of TCA cycle are repressed by fsrA, but downstream of succinate are not repressed by fsrA.

• Journal of Life Science
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• v.14 no.4
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• pp.608-613
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• 2004

Pyrimidine nucleotide N-ribosidase (pyrimidine 5'-nucleotide phosphoribo (deoxyribo) hydrolase/pyrimidine 5'-nucleoude nucleosidase, EC 3.2.2.10) directly catalyzes pyrimidine 5'-nucleotide to pyrimidine base and ribose (deoxyribo) 5-phosphate. In order to clarify the best nutritional conditions for the growth and the pyrimidine nucleotide N-ribosidase production of Pseudomonas oleovorans ATCC 8062 the effects of various nutrients such as different carbon and nitrogen sources were studied. For the both the growth and the enzyme production, 2% fumarate, 1.5% peptone, 5% corn steep liquor (CSL) and 1% ammonium chloride were excellent carbon and nitrogen sources, respectively. Optimum pH, temperature, and cultivation time for the enzyme production were 7.0, $28^{\circ}C$, and 48 h, respectively. The pyrimidine nucleotide N-ribosidase of P. oleovorans ATCC 8062 was not induced by UMP and its derivatives, and was constitutive enzyme.

• BMB Reports
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• v.32 no.4
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• pp.326-330
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• 1999

An aspartase purified from Hafnia alvei was inactivated by diethylpyrocarbonate (DEP) in a pseudo-first-order inactivation. The first-order plot was biphasic. The inactivation process was not saturable and the second order rate constant was $1.3\;M^{-1}s^{-1}$. The inactivated aspartase was reactivated with NH₂OH. The difference absorption spectrum of DEP-inactivated vs native enzyme preparations revealed a marked peak around 242 nm. The pH dependence of the inactivation rate suggests that an amino acid residue having a pK value of 7.2 was involved in the inactivation. L-aspartate, fumarate (substrates), and chloride ion (inhibitor) protected the enzyme against inactivation, indicating that histidine residues for the enzyme activity are located at the active site of this aspartase. Inspection of the presence and absence of $Cl^-$ ion demonstrated that the number of essential histidine residues is less than two. Thus, one or two histidines are in or near the aspartate binding site and participate in an essential step of the catalytic reaction.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.144-154
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• 2008

The rumen microbial ecosystem produces methane as a result of anaerobic fermentation. Methanogenesis in the rumen is thought to represent a 2-12% loss of energy intake and is estimated to be about 15% of total atmospheric methane emissions. While methanogenesis in the rumen is conducted by methanogens, PCR-based techniques have recently detected many uncultured methanogens which have a broader phylogenetic range than cultured strains isolated from the rumen. Strategies for reduction of methane emissions from the rumen have been proposed. These include 1) control of components in feed, 2) application of feed additives and 3) biological control of rumen fermentation. In any case, although it could be possible that repression of hydrogen-producing reactions leads to abatement of methane production, repression of hydrogen-producing reactions means repression of the activity of rumen fermentation and leads to restrained digestibility of carbohydrates and suppression of microbial growth. Thus, in order to reduce the flow of hydrogen into methane production, hydrogen should be diverted into propionate production via lactate or fumarate.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.106-109
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• 2006

Improvement of L-asparate ${\beta}-decarboxylase$ production from Pseudomonas dacunhae ATCC 21192 was attempted by optimizing fermentation conditions. Optimum carbon and nitrogen sources for cell growth and enzyme production were determined. L-Glutamate (2%) was the most suitable carbon source, and D-glucose, D-glycerol and fumarate repressed enzyme production. Yeast extract (2%) was the most effective as nitrogen source. A slight change of pH to 6.5 from medium pH resulted in a meaningful increase in the production of enzyme. The production of the enzyme was highly improved by using 2% yeast extract and 2% L-glutamate in culture media. Maximum L-asparate ${\beta}-decarboxylase$ activity reached up to over 24 U/mL-broth by 15 h flask fermentation.