• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.989-992
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• 2003

Recombinant human tissue plasminogen activator deletion mutein (Reteplase) is a clinically promising thrombolytic drug. Reteplase cDNA was subcloned into a bacteria expression system, and the resultant recombinant was biologically characterized. The Reteplase was expressed in Escherichia coli as an inclusion body, and the downstream processes of the Reteplase inclusion body included denaturation, renaturation, and purification. A protein disulfide isomerase (PDI) was used to assist the refolding of Reteplase, and it was found to increase the refolding rate from less than 2％ to more than 20％. The refolded Reteplase was purified through two chromatography steps, including lysine-coupled agarose affinity chromatography and then CM-sepharose cation-exchange chomatography. The purity of r-PA was analyzed by Western bolt analysis, and N-terminal amino acid and amino acid composition analyses confirmed the end-product. Reteplase showed higher thrombolytic potency in an animal thrombus model.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.124-135
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• 2003

In order to prevent pollution from animal waste, the excretion of nutrients should be reduced through proper nutritional management. Among the many nutrients of concern, such as N, P, Cu, Zn and K, P is one of the most concerned nutrients to be managed. Seven feeding trials, three with layers and four with broilers, were conducted to determine if microbial phytase supplementation can reduce non-phytate phosphorus (NPP) level in diets and results in concomitant reductions of P excretion. The results showed that microbial phytase can be successfully used to achieve these purposes. Activity of natural phytase in certain plant feedstuffs is high enough to be considered in feed formulation. Three experiments have been conducted to study the characteristics of plant phytase and its application to feeding of broilers. Selected brands of wheat bran could be successfully used as a source of phytase in broiler feeding.

• 한국균학회지
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• 제8권2호
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• pp.107-113
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• 1980

To investigate antitumor components of Korean higher fungi, the carpophores of Ganoderma lucidum (Fr.)Karst. were collected at Gal-mae-ri in Gyeong-gi Province and extracted with 0.1N sodium hydroxide solution. The extract was purified by dialyzing through Visking tube and a dark brownish power was obtained. The antitumor activity of the fraction was tested against sarcoma 180 implanted in mice. The tumor inhibition ratio of the fraction against the tumor was 87.6% in doses of 50 mg/kg/day for the period of ten days. The tumor in five of 15 mice was completely regressed. The antitumor fraction was chemically analyzed and found to be a complex of polysaccharide and protein, from which four monosaccharides and eighteen amino acids were identified.

• 한국물환경학회지
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• 제31권4호
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• pp.399-406
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• 2015

A sequencing batch reactor was operated under different pH conditions to see the influence of free ammonia (FA) and free nitrous acid (FNA) to microbial community on ammonium partial nitrification. Long-term influences of FA and FNA were evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis and fluorescence in situ hybridization. Nitrite accumulation was successfully achieved at pH 8.2 and 6.3. The shifts in the microbial community were observed when influent ammonia concentration increased to 1 g $NH_4$-N/L at pH 8.2, and then when pH was dropped to 6.3. Both Nitrosomonas and Nitrosospira were selected during the startup of the reactor, and eventually became dominant members as ammonia-oxidizing bacteria. The results of molecular microbiological analysis strongly suggested that the composition of microbial community was changed according to the method used to control nitrite-oxidizing bacteria.

• Journal of Microbiology
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• 제44권3호
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• pp.354-359
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• 2006

This study examined the capacity of immobilized bacteria to degrade petroleum hydrocarbons. A mixture of hydrocarbon-degrading bacterial strains was immobilized in alginate and incubated in crude oil-contaminated artificial seawater (ASW). Analysis of hydrocarbon residues following a 30-day incubation period demonstrated that the biodegradation capacity of the microorganisms was not compromised by the immobilization. Removal of n-alkanes was similar in immobilized cells and control cells. To test reusability, the immobilized bacteria were incubated for sequential increments of 30 days. No decline in biodegradation capacity of the immobilized consortium of bacterial cells was noted over its repeated use. We conclude that immobilized hydrocarbon-degrading bacteria represent a promising application in the bioremediation of hydrocarbon-contaminated areas.

• Journal of Microbiology
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• 제43권1호
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• pp.49-53
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• 2005

Putative genes for a two-component signal transduction system (akbS and akbT) were detected near the alkylbenzene-degrading operon of Rhodococcus sp. DK17. Sequence analysis indicates that AkbS possesses potential ATP-binding and histidine autophosphorylation sites in the N- and C-terminal regions, respectively, and that AkbT has a typical response regulator domain. Mutant analysis combined with RT-PCR experiments further shows that AkbS is required to induce the expression of o-xylene dioxygenase in DK17.

• Preventive Nutrition and Food Science
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• 제6권4호
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• pp.240-243
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• 2001

Fresh pasta was packaged in a modified atmosphere of 22% $CO_2$/78% $N_2$ and compared with a control air package for its quality changes during storage at 8$^{\circ}C$. The modified atmosphere packaging suppressed the microbial growth of total aerobic bacteria and yeasts/molds with a concomitant reduction in the rates of physical and chemical quality changes, and thus successfully extended the shelf life of fresh packs from 20 days of air packs to 40 days based on microbial criterion of 10$^{6}$ cfu/g. The shelf life extension was greater when the initial microbial quality of the product was better.

• 한국물환경학회지
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• 제31권5호
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• pp.556-562
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• 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of $SCOD_{Cr}$ did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was $129.2{\pm}13.54g\;NO_3{^-}-N/m^3/d$ in the external resistance $1{\Omega}$, and the maximum power density was $3,279mW/m^3$ in $10{\Omega}$. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the $NO_3{^-}-N$ removal efficiencies were increased linearly, and the maximum nitrate removal rate was $1,586g\;NO^3{^-}-N/m^3/d$ at HRT 0.6 h.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.429-435
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• 1999

An adenosine 5'-monophosphate deaminase (AMP aminohydrolase, EC 3.5.4.6) was purified to homogeneity from the cell-free extract of Saccharomyces cerevisiae DKCTC7248. The molecular mass of subunit was estimated to be 80 kDa on SDS-PAGE, and that of the holoenzyme was shown to be 240 kDa by gel filtration. The isoelectric point of the enzyme (AMP deaminase D) was determined to be 6.2. The AMP deaminase D was specific towards AMP with an apparent $K_m$ value of 4.1 mM and a Hill coefficient, $n_H$, of 2.2. Both ATP and ADP were positive allosteric effectors of the AMP deaminase D: The apparent $K_{m}$ was decreased to 1.6 mM and 3.3 mM in the presence of 0.1 mM ATP and ADP, respectively, lowering $n_{H}$ to 1.0. Univalent cations like $K^+, Na^+ and Li^ +$ activated the enzyme but some divalent cations such as $Cu^{ 2+} and Cd^{2+}$ showed strong inhibitory effects. This enzyme displayed optimum activity at $30^{\circ}C$ and pH 7.0. In addition, it was stable up to $45^{\circ}C$ and over a wide pH range(pH 5.5-9.0). Amino acid sequences of its N-terminal region were analyzed to be ADYKMQMFADDA.

• 한국물환경학회지
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• 제22권3호
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• pp.492-497
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• 2006

Feasibility of simultaneous removal of organic materials and nitrogen in the wastewater from fisheries processing plant was evaluated using entrapped mixed microbial cell (EMMC) process. The experiment was performed using activated sludge from municipal sewage treatment plant which was immobilized with gel matrix by cellulose triacetate. It was found the stable operation at the treatment system which is composed of anoxic and oxic tank, was possible when the organic and nitrogen loading rates were increased stepwise. The organic and nitrogen loading rates were conducted from 0.65 to $1.72kgCOD/m^3/d$ and from 0.119 to $0.317kg\;T-N/m^3/d$ with four steps, respectively. The maximum nitrogen loading rate which could satisfy the regulated effluent standard of nitrogen concentration, was $0.3kg\;T-N/m^3/d$. The removal efficiency of total nitrogen was decreased apparently as increasing nitrogen loading rates, whereas the removal efficiency of ammonium nitrogen was effective at the all tested nitrogen loading rates. Therefore, it was concluded that nitrification was efficient at the system. Nitrate was removed efficiently at the anoxic tank. whereas the nitrification efficiency at the oxic tank ranged 94.0% to 96.9% at the tested loading rates. The removal efficiencies of chemical oxygen demand (COD) and those of total nitrogen at the entire system ranged from 94.2% to 96.6% and 73.4% to 83.4%, respectively.