• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.597-604
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• 2011

This research analyzed the runoff patterns and estimated unit loads of selected pollutatnts using monitored data conducted for three years in a bridge area. Three estimating methods; the arithmetic average method, the regression method and the rainfall class method were used to estimate the unit load. Results of three estimating methods were compared with the unit pollutant loads from landuses in Korea and the unit pollutant loads from urban watersheds in Milwaukee, USA. Unit load using the arithmetic mean method were found to be overestimated. In terms of TSS, unit loads of two estimate were half lower than that of USA. Estimated TN and TP unit loads of three estimate were lower than that of Ministry of Environment in Korea.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.98-102
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• 1996

A thermostable tyrosine phenol-lyase gene of a thermophilic Symbiobacterium species was cloned and overexpressed in Escherichia coli in order to produce the biocatalyst for the synthesis of 3, 4-dihy-droxyphenyl-L-alanine (L-DOPA). The substrates used for the synthetic reaction were pyrocatechol, so-dium pyruvate, and ammonium chloride. The enzyme was stable up to $60^{\circ}C$, and the optimal temperature for the synthesis of L-DOPA was $37^{\circ}C$ . The optimal pH of the reaction was about 8.3. Enzyme activity was highly dependent on the amount of ammonium chloride and the optimal concentration was estimated to be 0.6 M. In the case of pyrocatechol, an inactivation of enzyme activity was observed at con-centrations higher than 0.1 M. Enzyme activity was increased by the presence of ethanol. Under op-timized conditions, L-DOPA production was carried out adding pyrocatechol and sodium pyruvate to the reaction solution intermittently to avoid substrate depletion during the reaction. The concentration of L-DOPA reached 29.8 g/l after 6 h, but the concentration didn t increase further because of the formation of byproducts by a non-enzymatic reaction between L-DOPA and pyruvate.

• Journal of Microbiology and Biotechnology
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• v.6 no.4
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• pp.250-254
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• 1996

MR-387A [(2S, 3R)-2-hydroxy-3-amino-4-phenylbutanoyl-L-valyl-L-prolyl-(2, 4-trans)- L-4-hydroxy-proline] reversibly inhibits aminopeptidase N (BC 3.4.11.2) in a process that is remarkable for its unusual degree of time dependence. The time required to inactivate the enzyme by 50$%$ ($t_{1/2}$) for establishing steady-state levels of $EI^*$complex was approximately 5 minutes. This indicates that the inhibition is a slow-binding process. In dissociation experiments of $EI^*$ complex, enzymic activity was regained slowly in a quadratic equation, indicating that the inhibition of aminopeptidase N by MR-387A is tight-binding and reversible. Thus, the binding of MR-387A by aminopeptidase N is slow and tight, with $K_{i}$ (for initial collision complex, EI) and $K_i{^*}$ (for final tightened complex, $EI^*$) of $2.2\times10^{-8}$ M (from Lineweaver-Burk plot) and $4.4\times10^{-10}$ M (from rate constants), respectively. These data indicate that MR-387A and aminopeptidase N are bound approximately 200-fold more tightly in the final $EI^*$complex than in the initial collision EI complex.

• BMB Reports
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• v.32 no.6
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• pp.561-566
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• 1999

CA(1-8)-ME(1-12) [CA-ME], composed of cecropin A(1-8) and melittin(1-12), is a synthetic antimicrobial peptide having potent antibacterial and antitumor activities with minimal hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly, of CA-ME on antibiotic activity, CA-ME and three analogues, CA-ME1, CA-ME2, and CA-ME3, were synthesized. The Gly-Ile-Gly sequence of Ca-ME was deleted in CA-ME1 and replaced with Pro and Gly-Pro-Gly in CA-ME2 and CA-ME3, respectively. CA-ME1 and CA-ME3 showed a significant decrease in antitumor activity and phospholipid vesicle-disrupting ability. However, CA-ME2 showed similar antitumor and vesicle-disrupting activities, as compared with CA-ME. These results suggest that the flexibility or ${\beta}$-turn induced by Gly-Ile-Gly or Pro in the central part of CA-ME may be important in the electrostatic interaction of the N-terminus cationic ${\alpha}$-helical region with the cell membrane surface and the hydrophobic interaction of the C-terminus amphipathic ${\alpha}$-helical region with the hydrophobic acyl chains in the cell membrane. CA-ME3 exhibited lower antitumor and vesicle-disrupting activities than CA-ME and CA-ME2. This result suggests that the excessive ${\beta}$-turn structure caused by the Gly-Pro-Gly sequence in CA-ME3 seems to interrupt ion channel/pore formation in the lipid bilayer. We concluded that the appropriate flexibility or bilayer. We concluded that the appropriate flexibility or ${\beta}$-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.618-624
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• 1998

The culture conditions for Bacillus sp. DP-152 in the flask were investigated for the production of polysaccharide locculant, DP-152. The optimum pH and temperature for the locculant production were 8.0 and $30^{\circ}C$, respectively. The avorable substrates for flocculant production were soluble tarch and ammonium nitrate. The medium composition was optimized as follows: 30 g soluble starch, 0.75 g $NH_4NO_3,\; 2.0g\; K_2\;HPO_4,\; 0.1\; g KH_2PO_4,\; 0.2g\; MgSO_4.\; 7H_2O,\; and\; 0.2g\; MnSO_4~5H_2O$ in 11 of distilled water. Under this optimized condition, flocculating activity has been improved 4-fold compared with that of the basal medium. In the culture flask, the highest flocculating activity was obtained after 70 h of cultivation and the amount of bioflocculant DP-152 yielded was 12.4 g/$\ell$. The solution of bioflocculant DP-152 showed non-Newtonian characteristics. Bioflocculant DP-152 exhibited apparently higher viscosity at all concentrations compared to that of zooglan (from Zoogloea ramigera), and it was stable over a wide range of temperatures and pHs.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.595-600
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• 1998

In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

• BMB Reports
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• v.33 no.1
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• pp.92-95
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• 2000

The HIV-1 p24(202-221) sequence ETINNEEEWDRVHPV HAGP contains a B-cell epitope with the earliest immune response and the highest antibody titer against anti-mouse sera obtained by immunization with p24 antigens. A novel mouse monoclonal antibody (mAb) was generated against the immunodominant B-cell epitope of the HIV-1 p24 capsid protein, p24(202-221). BALB/c mice were immunized with the four branched multiple antigenic peptide (MAP) containing the HIV-1p24(202-221) sequence, and antibody-secreting hybridoma were produced by fusion of mouse splenocytes with P3X63Ag8.653, mouse myeloma cells. One clone which produced the antigen-specific mAb named KI-24 (Isotype IgG1, light chain: ${\kappa}$) was identified. mAb KI-24 was highly specific for both the p24(202-221) and p24 proteins when analyzed by ELISA and Western blotting. Since p24(202-221) also contains a cytotoxic T-lymphocyte epitope, this specfic peptide epitope and the monoclonal antibody with specific reactivity against the p24 protein and p24(202-221) can be used in peptide vaccine development and p24 antigen detection from HIV patients.

• BMB Reports
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• v.31 no.1
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• pp.58-63
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• 1998

In this study, a mouse monoclonal antibody (mAb) against gp41(584-618), the immunodominant epitope protein, was generated. For this purpose, BALB/c mice were immunized with double branched multiple antigenic peptides derived from the HIV-1 gp41(584-618) sequence, and antibody-secreting hybridoma were produced by fusion of mice splenocytes with SP2/0 myeloma cells. One clone producing an antigen specific mAb, termed KI-41(isotype IgG1) was identified, whose specific reactivity against gp41(584-618) could be confirmed by ELISA and Western blot analysis. Epitope mapping revealed the recognition site of the mAb KI-41 to be located around the sequence RILAVERYLKDQQLLG, which comprises the N-terminal region within the immunized gp41(584-618) peptied. Since this mAb recognizes this specific epitope within the HIV-1 gp41 without any cross-reactivity to other immunodominant regions in the HIV-2 gp35, KI-41 will provide some alternative possibilities in further applications such as the development of indirect or competitive ELISA for specific antibody detection in HIV-1 infection or for other basic researches regarding the role and function of HIV-1 gp41.

• BMB Reports
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• v.31 no.2
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• pp.111-116
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• 1998

HLA-DR4 is the dominant allele of MHC class II genes in Koreans. In particular, the $DRB1^*0405$ subtype has been reported to be almost exclusively expressed in Far East Asians, and has also been observed to be strongly associated with rheumatoid arthritis in Koreans and the Japanese. Identification of this specific allele has been mainly performed by PCR-based methods, which is often time consuming, costly, and involves tedious procedures such as the isolation of genomic DNA, PCR, and gel electrophoresis. To develop a more convenient tool for screening vast amounts of samples as well as to generate reagents which might also be used in other applications, in this study, antibodies were produced against this specific HLA subtype. By PCR, an allelespecific region covering the ${\beta}1$ domain of $DRB1^*0405$ was amplified and recombinantly expressed in E.coli. Immunization of Lewis rats with the purified protein yielded an allele specific antiserum. Western blot analysis showed the selective detection of the HLA-DR ${\beta}-chain$. Using this antiserum, established cell lines and peripheral blood lymphocytes were analyzed on their HLA haplotype by fluorescence activated flow cytometry. These novel antibodies will provide a powerful tool in the detection and investigation of DR4 alleles.

• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.205-209
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• 1997

Potato spindle tuber viroid(PSTVd) RNAs were isolated from PSTVd-inoculated potato cv. Superioc and carried out RT-RCR with reverse transcriptase and PSTVd specifie primer pair desigened to amplify the 356 nucleotides of PSTVd genome. As a result, 356 nucleotides PCR products were amplified from PSTVd-inoculated potato cv. Superior. The 356 nucleotides DNA fragment was indeed the PSTVd geneby sequencing analysis. PSTVd could be successfully detected from infected leaf and tuber tissue of potato by using RT-PCR technique. Especially PSTVd was more effectively detected when both downstream and upstream primer were used than only downstream primer was used in RT reaction.