• Applied Biological Chemistry
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• v.46 no.2
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• pp.74-78
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• 2003

To determine the urease inhibitory activity of various heavy metal ions, a photometric cuvette assay for measuring ammonia production was developed. In this assay, the absorbance values at 630 m were linearly increased according to the ammonia concentrations up to 3.0 mg/l (r : 0.998). The urease inhibitions upon addition of a single species of heavy metal ions were in the decreasing order of Hg(II) > Pb(II) > Cu(II) > Cd(II) > Zn(II) ions. As expected, the urease inhibitions at a fixed concentration of a single species and at varying concentrations of other species occurred in the additive way. The above results show the applicability of the current method to the selective detection on Hg(II) ions as well as the screening of heavy metal ions possibly present at various samples.

• Journal of Life Science
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• v.8 no.5
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• pp.497-503
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• 1998

Cyclodextrinase from B. stearothemophilus KJ16 that can produce both cyclodextrin(CD) glucanotransferase and cyclodextrinase was purified 87.6-fold with 7% yield by ammonium sulfate precipitation, DEAE-cellulose chromatog-raphy, Sephadex G-100 chromatography, and FPLC. The molecular weight of the purified enzyme was about 68,000 dalton by SDS-PAGE. The optimal pH and temperature were 6.0 and 55$^{\circ}C$, respectively. The enzyme was stable at 5$0^{\circ}C$ for 2 hr in the pH range of 5.5 and 8.5. The enzyme activity was inhibited strongly by mercaptoethanol, di-thiothreitol, p-chloromercuribenzoate, N-bromosuccinimide, $Cu^{+2}$and $Hg^{+2}$. The purified enzyme hydrolyzed CDs with$\gamma$-CD>$\beta$-CD>$\alpha$-CD. The enzyme also hydrolyzed linear maltodextrins and polysaccharides, but the rates of hyd-rolysis for such substrates were slow as compared to that for $\gamma$-CD. The final degradation products with all substrates were maltose and glucose. Maltose was not further hydrolyzed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.1020-1025
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• 1995

A new method was developed to prepare ${\beta}-1$, 4-mannotriose by the enzymatic hydrolysis of white copra meal and the subsequent elimination of monosaccharides and mannobiose from the resulted hydrolysate with a yeast. The optimum pH and temperature for the mannanase were 6 and $50^{\circ}C$, respectively. The mannanase was stable between pH 5.5 and 7 after 2hr treatment at $30^{\circ}C$. White copra meal(70g) was hgydrolyzed with the mannanase(3,450units/500ml) at pH 6 and $50^{\circ}C$ for 24hr. The hydolysis products were monosaccharides, mannobiose and mannotriose. By the elimination of monosaccharides and mannobiose from the hydrolysis products with Candida guilliermondii IFO 0556, 12.1g of mannotriose was obtained without the use of chromatographic techiniques.

• Journal of Genetic Medicine
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• v.6 no.2
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• pp.146-154
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• 2009

Multiplex ligation dependent probe amplification (MLPA) is a PCR-based method to detect gene dosage. Since its introduction, MLPA has been used to test a large number of genes for major deletions or duplications. Genetic testing, as a diagnostic tool for genetic disease, has been used primarily to identify point mutations, including base substitutions and small insertions/deletions, using PCR and sequence analysis. However, it is difficult to identify large deletions or duplications using routine PCR- gel based assays, especially in heterozygotes. The MLPA is a more feasible method for identification of gene dosage than another routine PCR-based methods, and better able to detect deleterious deletions or duplications. In addition to detection of gene dosage, MLPA can be applied to identify methylation patterns of target genes, aneuploidy during prenatal diagnoses, and large deletions or duplications that may be associated with various cancers. The MLPA method offers numerous advantages, as it requires only a small amount of template DNA, is applicable to a wide variety of applications, and is high-throughput. On the other hand, this method suffers from disadvantages including the possibility of false positive results affected by template DNA quality, difficulties identifying SNPs located in probe sequences, and analytical complications in quantitative aspects.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.105-110
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• 2004

Microorganism (strain DF 218) producing thermostable pretense was isolated from Korean soil and compost. It was Gram-positive, rod-shaped, aerobic, and spore-forming with yellowish white colony color, Temperature range for growth at pH 6.5 was $30-65^{\circ}C$, with optimum growth at $60^{\circ}C$. pH range for growth at $60^{\circ}C$ was 5-7 with optimum of 6.5, which indicates strain DF 218 to be thermophilic. The 16S rDNA sequence of strain DF 218 had 95% sequence similarity with that of Bacillus flexus. Based on physiological properties and phylogenetic analysis, we proposed the isolated strain as Bacillus sp. DF 218. Pretense was produced aerobically at $60^{\circ}C$ for 32 hr in a medium (pH 6.5) containing 1% each trypton, glucose, and NaCl. Its molecular weight was estimated as 61 kDa, with optimum temperature and pH of $60^{\circ}C$ and 7.5, respectively.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.456-464
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• 1998

For the standardization and quality improvement of traditional Korean Nuruk, 10 strains of fungi, which were isolated from Nuruks and showed good productivity of the saccharogenic and dextrinogenic enzymes, acid and flavor, were selected and their enzymological characteristics and identification were carried out. Aspergillus spp. and Rhizopus sp. showed a high liquefying activity without regard to cultivation time, whereas the majority of strains except for Rhizopus sp. had decreasing saccharifying activity in proportion to the increase in cultivation time. Aspergillus spp. No.17-2, No.17-6 and Rhizopus sp. No.18-1 showed high liquefying and saccharifying activity after 15 and 30 day cultivation. The optimum temperature of most of these saccharogenic and dextrinogenic enzymes was from 40$^{\circ}C$ to 60$^{\circ}C$, and their optimum pH was extensive between pH 3 and pH 11. But Penicillium spp.(2 strains) and Rhizopus sp. showed low activity under the alkalic and acidic conditions. Among these isolated strains, 5 strains which had shown the high productivity of materials were identified as Aspergillus oryzae NR3-6 and Aspergillus oryzae NR17-6, Aspergillus penicilloides NR12-1, Penicillium expansum NR7-7 and Rhizopus oryzee NRl8-1, respectively. Five kinds of mixed culture were carried out and all of them showed a better productivity of saccharogenic and dextrinogenic enzymes than single culture. These results indicate that it is possible to make traditional Korean liquors of good quality by using these fungi.

• Journal of Life Science
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• v.16 no.1
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• pp.1-5
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• 2006

This study investigated the optimal conditions of high yield production of cyclofructan (CF) using recombinant deletion mutant enzyme CFT108 which is constructed by N-terminal deletion from cycloinulooligosaccharide fructanotransferase (CFTase) gene of Penibacillus polymyxa. The production yield was dependent on reaction time, substrate concentration and enzyme concentration. The optimum reaction time for industrial purpose was achieved at 3 hr reaction. The optimal concentrations of substrate and enzyme were found to be $2\%$ inulin and 40 unit/ g inulin, respectively. At optimum condition, 9.5 g/l of maximum yield and $47.5\%$ of conversion efficacy were achieved. For purification of CF produced, the reaction mixture was treated with 1 unit/ml exoinulinase and then added $3\%$ CaO three times with blowing $CO_2$ gas, resulted in $95\%$ purity.

• Journal of Gastric Cancer
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• v.8 no.3
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• pp.113-119
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• 2008

Purpose: This study investigated whether a single nucleotide polymorphism (SNP) located at position -2 in the Kozak sequence of the TFF1 gene is associated with H. pylori infection and the development of gastric cancer in Koreans. Materials and Methods: We enrolled 167 patients with gastric cancer from January 2000 to December 2003 and also 299 healthy controls during the same period. The genotype of the TFF1 SNP was analyzed by polymerase chain reaction-restriction fragment length polymorphism and single strand conformation polymorphism. We also examined the H. pylori infection by Giemsa staining. Results: No significant difference in the allele or the TFF1 SNP genotype frequency was observed between the patients with gastric cancer and the control subjects (P=0.595 and P=0.715, respectively). When stratified by the histological subtype of gastric cancer and the age of the patients, the risk was not statistically significant between the two study groups (P=0.088 and P=0.551, respectively). H. pylori infection was detected in 39 cases and it was not associated with the TFF1 genotype. Conclusion: These findings suggest that this TFF1 gene polymorphism is not associated with H. pylori infection and gastric cancer in Koreans and so it doesn't contribute to the susceptibility to gastric cancer in Koreans.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.105-110
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• 1985

A incubation study was conducted to find out the effects of rice straw and gypsum as soil ameriolite on urease, nitrate and nitrite reductase activities in newly reclaimed saline sandy soil. The results obtained were summarized as follows: 1. Very low urease activities were observed in saline soil if contrast to high productive paddy soil. Urease activities were lower at 5 days than that of 25 and 50 days after incubation. Remarkably high urease activities were obtained by the application of rice straw and gypsum. 2. Comparing with NPK treatment, application of rice straw and gypsum were enhanced the activities of nitrate and nitraite reductase. 3. Positive correlation (r=0.5501 p=0.05) was obtained between urease activities and ammonium nitrogen concentration in soil. 4. Cyclic oxidation and reduction of nitrate and nitrite in soil were obtained in terms of first order microbial kinetics reaction in case of application of rice straw and gypsum, respectively. 5. Positive correlation (r=0.6296 p=0.05) was obtained between the activitie of nitrite reductase and nitrate reductase in soil.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.81-86
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• 2005

One of the endoglucanases, F-I-III, was purified from the culture filtrate of T. sp. C-4 through procedures including chromatography on Sephacryl S-200, DEAE-Sepharose A-50, and Chromatofocusing on Mono-P (FPLC). The molecular weight of the enzyme was determined to be about 56,000 Da by SDS-PAGE, and pI of 4.9 by analytical isoelectric focusing. F-I-III showed the highest enzyme activity at $55^{\circ}C$, and the pH optimum of the enzyme was 5.0. There was no loss of activity when the enzyme was incubated at $50^{\circ}C$ for 24 hours. The specific activity of the enzyme F-I-III toward the CMC was 315.4 U/mg. The Km value for $PNPG_2$ of F-I-III was 2.69 mM. N-terminal sequence of F-I-III was analyzed to be QPGTSTPEVHPKKLTTYK. It showed $95\%$ of homology to that of EGI from T. reesei. The presence of some metal ions (1 mM) had only a little effect on CMCase activity. The treatment of the reducing agents resulted in the increase of endoglucanase activity.