• Journal of the Korean Electrochemical Society
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• v.7 no.1
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• pp.26-31
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• 2004

The direct electrochemical studies of four laccases (plant and fungal laccases) have been investigated on a gold electrode functionalized with a new tether of 2.2'-dithiosalicylic aldehyde. Results from these studies indicate that the redox potential of the active site of plant laccase from Rhus vernificera is shifted to a more negative value(255 mV versus SCE) than that of fungal laccase from Pyricularia oryzae (480 mV versus SCE). Mechanistic studies indicate that the reduction of type-1 Cu precedes the reduction of type-2 and type-3 Cu ions when the electrode is poised initially at different potentials. Also a new tether, 2.2'-dithiosalicylic aldehyde, has been used to study the redox properties of two laccases (LCCI and Lccla) covalently attached to a gold electrode. An irreversible peak at 0.47V vs. SCE is observed in the cyclic voltammorams of LCCI. In contrast, the cyclic voltammograms of LCCIa contain a quasi-reversible peak at 0.18V vs. SCE and an irreversible peak at 0.50V vs. SCE. We find that the replacement of the eleven amino acids a the C-terminus with a single cysteine residue $(i.e., \;LCCI{\rightarrow}LCCIa)$ influences the rate of heterogeneous electron transfer between an electrode and the copper containing active sites $(K_{het}\;for\;LCCI=1.0\times10^{-2}\;s^{-1}\;and\;K_{het}\;for\;LCCI_a= 1.0\;times10^{-1}\;s^{-1}\'at\;0.18V\;versus\;SCE\;and\;4.0\times10^{-2}\;s^{-1}\;at\;0.50V\; versus\;SCE)$. These results show for the first time that the change of the primary structure of a protein via site-directed mutagenesis influences both the redox potentials of the copper ions in the active site and the rate of heterogeneous electron transfer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.336-341
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• 2024

In this study, the economic and environmental feasibility of seaweed by-products as livestock feed ingredients was evaluated. In the last three years (2021-2023), the estimated average annual production of domestic seaweed by-products, including processing residuals from sea mustard and kelp, was 210,000 tons. The economic feasibility analysis of using seaweed by-products as livestock feed indicated a net benefit of 482,237 KRW per ton. Additionally, substituting seaweed by-products at 0.25% 0.5%, 1%, and 2% in livestock compound feed generated net benefits of 6.5, 12.9, 25.9, and 51.7 billion KRW, respectively. The potential market value was analyzed from an environmental perspective by examining the greenhouse gas reduction potential of seaweed additives. By adding 2% laver, 2% sea mustard, and 0.25% sea mustard sporophyll to the feed, greenhouse gas emissions could be reduced by economic values estimated at 10.8, 11.4, and 15.6 billion KRW, respectively. The findings of this study suggest that the use of seaweed by-products livestock as feed ingredients can generate economic and environmental benefits.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.101-108
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• 2008

This study attempted to develop the technology by gaseous ozone for decontaminating building affected by a model of biological weapon agent(Bacillus subtilis spores) instead of Bacillus anthracis spore. The use of ozone is attractive method from a practical point of view of decontamination procedure since it has strong oxidation power but no residue after application. We examined the disinfection efficiency of gaseous ozone to Bacillus subtilis spores which suspension was sprayed on different material surfaces and dried. Three different types of gaseous ozone was applied : dry ozone, dry ozone with humidified air, and water bubbled wet ozone. Dry ozone(1500ppm) failed to achieve any significant inactivation for 2hrs. However, six log reduction of B. subtilis spore was achieved within 30min by 1500ppm of water bubbled wet ozone. This result shows the noticeable inactivation efficiency by gaseous ozone compared with previous studies. Good performance by wet ozone was also found for military material surface.(i.e. : gas mask hood, protective garments, army peinted metal surface).

• KSBB Journal
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• v.27 no.4
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• pp.227-231
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• 2012

Whole plants of Zostera asiatica were extracted twice with acetone/methylene chloride (A+M) and methanol (MeOH) in turn. The combined crude extracts were evaporated in vacuo and then the residue was partitioned between water and methylene chloride. The aqueous layer was fractionated into $H_2O$ and n-butanol and then the organic layer was also fractionated into 85% aq. MeOH and n-hexane, successively. The crude extracts and their solvent fractions were evaluated for their inhibitory effect on growth of human cancer cells AGS, HT-29, MCF-7, and HT-1080 cells by MTT reduction assay. Among samples tested, 85% aq. MeOH and n-hexane fractions showed strong cytotoxic effect against AGS, HT-29, and MCF-7 cells. On the other hand, for HT-1080 cell, 85% aq. MeOH fraction exhibited the strongest cytotoxic effect.

• BMB Reports
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• v.42 no.7
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• pp.439-443
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• 2009

Dehydrins are group II, late embryogenesis abundant proteins that act putatively as chaperones in stressed plants. To elucidate the function of dehydrins in poplar, we isolated the $SK_2$-type dehydrin gene Podhn from Populus alba $\times$ P. tremula var. glandulosa suspension cells and analyzed its expression following treatments of abiotic stress, wounding and plant growth regulator. Sequence homology and phylogenetic analyses indicate Podhn encodes an acidic dehydrin (pI 5.14, 277 amino acids, predicted size 25.6 kDa) containing two lysine-rich "K-segments" and a 7-serine residue "S-segment", both characteristic of $SK_2$-type dehydrins. Southern blots show Podhn genes form a small gene family in poplar. Podhn was expressed in all tissues examined under unstressed conditions, but most strongly in cell suspensions (especially in the stationary phase). Drought, salt, cold and exogenous abscisic acid (ABA) treatments enhanced Podhn expression, while wounding and jasmonic acid caused its reduction. Therefore, Podhn might be involved in ABA or stress response.

• Biomedical Science Letters
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• v.14 no.2
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• pp.119-122
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• 2008

The baculovirus/insect cell expression system is of great value in the study of structure-function relationships in mammalian glucose-transport proteins by site-directed mutagenesis and for the large-scale production of these proteins for mechanistic and biochemical studies. In order to exploit this, the effects of substitution at the highly conserved residue glutamine 282 of the human erythrocyte-type glucose transporter have been examined by in vitro site-directed mutagenesis. The modified human transport protein has been expressed in Spodoptera frugiperda 21 cells by using the recombinant baculovirus AcNPV-GTL. To assess the functional integrity of the expressed transporter, measurements of the transport inhibitor cytochalasin B binding were performed, involving the membranes prepared from 4 days post infection with no virus, with wild-type virus or AcNPV-GTL virus. Data obtained showed that there was little or no D-glucose-inhibitable binding in cells infected with the wild type or no virus. Only the recombinant virus infected cells exhibited specific binding, which is inhibitable by D- but not by L-glucose. However, there was a notable reduction in the affinity for the potent inhibitor cytochalasin B when binding measurements of AcNPV-GTL were compared with those of AcNPV-GT, which has no substitution. It is thus suggested that although the modified and unmodified human transporters differed slightly in their affinity for cytochalasin B, the glutamine substitution did not interfere the heterologous expression of the human transporter in the insect cells.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.14-20
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• 2016

This paper describes a green stripping process to effectively strip the remaining DFR layer on a non-alkali-based ITO glass surface after an etching process. A stripper, water-soluble amine compound, is used to investigate the characteristics of stripping ability and to suggest a valid method for the green process. Increasing the composition (5-30% concentration) of the ethanol amine-based stripper was found to greatly reduce the stripping time applied in the dipping method. The composition (30%) achieved an excellent stripping effect and free-residue impurities. Additionally, it was possible to obtain the effect of stripping in a way to sustain the release before generating DFR sludge from the ITO glass surface by using dipping condition (stripping time) in the composition. An Additional stripping process (buffering) out of dipping can realize productivity improvement and cost reduction because of the higher proportion of re-use of the stripping solution used in the DFR removal step.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.710-716
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• 1995

$\beta $-1, 4-D-arabinogalactanase isolated from alkalophilic Bacillus sp. HJ-12, approximate Mw 42 kDa, was generally stable in the range of pH 6-10 and below 50$\circ$C and its highest activity was observed at 60$\circ$C with pH 7-9. The isolated $\beta $-1, 4-D-arabinogalactanase specifically hydrolyzed $\beta $-1, 4-galactosyl linkage that is the major structure of soybean arabinogalactan (SAG) but not $\beta $-1, 3-galactosyl linkage of the other polysaccharides. K. was estimated as 0.67 mg/ml by the method of Hanes-Woolf plot. No metals and chemical reagents inhibited the enzyme activity but urea did. The active site of this enzyme assumed to be tryptophan residue. The hydrolysis products from SAG, assayed by gel chromatography, TLC and HPLC, were predominantly galactotetraose (Gal$_{4}$) and triose (Gal$_{3}$) with a small portion. $\beta $-1, 4-D-arabinogalactanase hydrolyzed ONPG as well as SAG, and the degree of hydrolysis of SAG was 15% which is lower than that by the other $\beta $-1, 4-galactanases from different sources. SAG treated with this enzyme resulted in the reduction of specific viscosity up to 70%.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.10a
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• pp.29-34
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• 2004

Reduction in stratospheric ozone layer increases the amount of ultraviolet-B radiation (UVB: 280-320 nm) that reaches the earth ’ s surface. UVB radiationcan damage plants, resulting in decrease in growth and productivity. UVB-augmentation studies have indicated that the sensitivity to UVB radiation in plants varies among the species and cultivars. However. there are no definitive answers for the mechanisms of UVB-resistance in higher plants and for bioengineering design and development of UVB-tolerant plants. We have been studying physiological and biochemical aspects of the effects of UVB radiation on growth and yield of rice COryza sativa LJ. aiming to clarify the mechanism of resistance to UVB radiationin rice. At this meeting. weintroduce our research as followed: (1) supplementary UVB radiation has inhibitory effects on the growth. yield and grain development of rice; (2) UVB sensitivity of rice varies widely among cultivars; (3) among Japanese rice cultivars. Sasanishiki. a leading variety in northeast Japan. is more resistant to UVB. while Norin 1. a progenitor of Sasanishiki. is less resistant; (4)UV-sensitive Norin 1 cultivar is deficient in photorepair of UVB-induced cyclobutane pyrimidine dimer (CPD). and this deficiency results from one amino acid residue alteration of CPD photolyase. These results suggest that spontaneously occurring mutation in CPD photolyase gene could lead to difference in UVB sensitivity in rice. and that CPD photolyase might be a useful target for improving UVB-sensitivity in rice by selective breeding or bioengineering of UVB-tolerant rice.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.657-662
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• 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO (reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most (>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.