• The Korean Journal of Ecology
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• v.21 no.3
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• pp.225-231
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• 1998

The studies on the potentiality of biomonitoring heavy metal pollution in coastal region of industrial complex were performed to investigate the heavy metal accumulation and induction of metal-binding protein (MBP) as detoxification process using Rumex maritimus. Bioconcentration in organs and MBP in root of R. maritimus was investigated for the research of the tolerance of heavy metals. The bioconcentration of cadmium and zinc in organs showed 3.6-8.0 times in root higher than in shoot, so it was found that heavy metal accumulated selectively in root. MBP increased absorbance in 254 nm and decreased in 280 nm, because it was composed of high cystein content and low aromatic acids, so absorbance had large difference between 254 nm and 280 nm. The existence of MBP in the 10-20 fraction was ascertained with anion exchange chromatography and it was identified that concentration of heavy metal increased according as an exposure concentration of medium increased in QAE Sephadex A-25 elution profile. These results suggested that MBP could play a role in biomarker determining the bioconcentration of plant. This study demonstrated a possibility that removal ability of heavy metal of R. maritimus resulted from detoxification process and MBP could be utilized as a biomarker of heavy metal pollution.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4247-4252
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• 2011

The porphyrin-incorporated arylether dendrimers ZnP-D1 and ZnP-D4 were investigated to discover the influence of dendritic environments for the axial ligation of pyridine and photoinduced electron transfer by methyl viologen. Absorption and fluorescence spectra of ZnP, ZnP-D1, and ZnP-D4 were measured in dichloromethane with the addition of pyridine or methyl viologen dichloride. Axial ligation of pyridine was confirmed by red-shifted absorption spectrum. The complex formation constants $K_f$ (Table 1) for axial coordination of pyridine on ZnP, ZnP-D1, and ZnP-D4 were estimated to be $4.4{\times}10^3\;M^{-1}$, $3.3{\times}10^3\;M^{-1}$, and $1.7{\times}10^3\;M^{-1}$, respectively. The photoinduced electron transfer to methyl viologen dichloride was confirmed by fluorescence quenching. Stern-Volmer constants Ksv for ZnP, ZnP-D1, and ZnP-D4 were calculated to be $2.6{\times}10^3$, $2.5{\times}10^3$, and $2.1{\times}10^3$, respectively. ZnP-D4 surrounded by 4 aryl ether dendrons shows the smallest $K_f$ and Ksv values, with comparison to ZnP and ZnP-D1.

• BMB Reports
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• v.37 no.6
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• pp.663-670
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• 2004

ZNF 333 is a new and sole gene containing two KRAB domains which has been identified currently. It is a member of subfamilies of zinc finger gene complex which had been localized on chromosome 19p13.1. The ZNF333 gene mainly encodes a 75.5 kDa protein which contains 10 zinc finger domains. Using the methods of random oligonucleotide selection assay, electromobility gel shift assay and luciferase activity assay, we found that ZNF333 recognized the specific DNA core binding sequence ATAAT. Moreover, these data indicated that the KRAB domain of ZNF333 really has the ability of transcriptional repression.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.32-39
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• 2024

Glycerol dehydrogenase (GlyDH) plays a crucial role in the glycerol metabolism pathway by catalyzing the oxidation of glycerol to dihydroxyacetone (DHA). Previous studies of GlyDH have predominantly focused on unraveling the structural features of the active site and its binding interactions with ligand. However, the structural details of GlyDH in complex with both NAD⁺ and the substrate bound have remained elusive. In this study, we present the crystal structures of Klebsiella pneumoniae GlyDH (KpGlyDH) in the absence and presence of NAD⁺ at a resolution of 2.1 Å. Notably, both structures reveal the binding of the substrate, ethylene glycol, to the zinc ion. Interestingly, a significant change in the coordination number of the zinc ion is observed, with three in the absence of NAD⁺ and four in its presence. These findings shed light on the structural aspects of GlyDH and its interactions with NAD⁺ and the substrate.

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.1-7
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• 1965

Reaction of monochloroacetic acid with zinc in presence of toluene, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, and dioxane solvents showed the solvent effect in order of dimethylformamide, dioxane, dimethyl sulfoxide, toluene, acetonitrile, and tetrahydrofuran. The increasing reactivity of the reagents was observed in order of the polarity and hydrophilicity of the solvent. The same reaction of ethyl monochloroacetate in the same series of solvents showed also the solvent effect, but the difference was not large as compared to that of the acid. The reaction of the acid, ester, zinc, and carbonyl precursors such as benzaldehyde and 4-heptanone gave the Reformatsky reaction product in the case of the aldehyde, but the reactivity with 4-heptanone was slight. The yield of the product was varied by the method of addition of reagents. The best yield observed in case of the acid reaction was 38.5% of the hydroxy acid and 0.8g of the salt in presence of acetonitrile and in case of the ester reaction 19.3% of ethyl cinnamate and 21.6% of polymer. The variation of the reactivity of reagents due to the reaction temperature was observed in case of carbonyl reaction. The result was discussed in terms of the solvent effect and the procedures were described.

• Journal of Veterinary Science
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• v.21 no.1
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• pp.2.1-2.14
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• 2020

The emergence of livestock-associated (LA)-methicillin-resistant Staphylococcus aureus (MRSA) in livestock animal has become a significant zoonotic concern. In the present study, we investigated nationwide prevalence of LA-MRSA across pork production chain including pig farms, slaughterhouses, and retail markets. A total of 40 MRSA strains were isolated during the investigation and the overall prevalence of MRSA was 3.4% (n = 37), 0.6% (n = 2), and 0.4% (n = 1) in pig farms, slaughterhouses, and retail markets, respectively. Multilocus sequence typing analyses revealed that the 2 most significant clonal lineages in pork production chain in Korea were ST398 (n = 25) and ST541 (n = 6). All of the 40 MRSA isolates were further characterized to investigate key genotypic and phenotypic correlates associated with the emergence and spread of clonal complex 398 (CC398; ST398, and ST541) LA-MRSA. Although the prevalence of swine-associated MRSA was still relatively low and mostly restricted to pig farms, multidrug-resistant CC398 LA-MRSA isolates with new spa types (t18102 and t18103) were identified as a major clonal lineage. The CC398 LA-MRSA strains tended to exhibit increased levels of multiple drug resistance (MDR) phenotype compared with non-CC398 MRSA strains. Of note, in comparison with non-CC398 MRSA isolates, CC398 LA-MRSA isolates exhibited significantly enhanced tetracycline (TET) and zinc resistance. These findings suggested that co-selection pressure associated with MDR phenotype, especially TET resistance, and zinc resistance may have played a significant role in the emergence and persistence of CC398 LA-MRSA in pig farms in Korea.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1519-1526
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• 2023

For the first time Aluminium-BariumeZinc oxide nanocomposite (ZABONC) was synthesized by solution combustion method where calcination was carried out at low temperatures (600℃) to study the electromagnetic (EM) (X/γ) radiation shielding properties. Further for characterization purpose standard techniques like PXRD, SEM, UV-VISIBLE, FTIR were used to find phase purity, functional groups, surface morphology, and to do structural analysis and energy band gap determination. The PXRD pattern shows (hkl) planes corresponding to spinel cubic phase of ZnAl₂O4, cubic Ba(NO₃)₂, α and γ phase of Al₂O₃ which clearly confirms the formation of complex nano composite. From SEM histogram mean size of nano particles was calculated and is in the order of 17 nm. Wood and Tauc's relation direct energy band gap calculation gives energy gap of 2.9 eV. In addition, EM (X/γ) shielding properties were measured and compared with the theoretical ones using standard procedures (NaI (Tl) detector and multi channel analyzer MCA). For energy above 356 keV the measured shielding parameters agree well with the theory, while below this value slight deviation is observed, due to the influence of atomic/crystallite size of the ZABONC. Hence synthesized ZABONC can be used as a shielding material in EM (X/γ) radiation shielding.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.321-326
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• 2002

ZnWO$_4$ nano-powders were successfully prepared by polymerized complex method using zinc nitrate and tungstic acid as starting materials. In order to investigate the thermal decomposition and crystallization process, the polymeric precursors were heat-treated at temperatures from 300 to 600$^{\circ}$C for 3 h, and the heat-treated powders were characterized by XRD and FTIR. The surface morphology of the heat-treated powders were observed using SEM and TEM. The crystallite size was measured by X-ray analysis. Crystallization of the ZnWO$_4$ powders were detected at 400$^{\circ}$C and entirely completed at a temperature of 600$^{\circ}$C. The particles heat-treated 400 and 500$^{\circ}$C showed primarily co-mixed morphology with spherical and silkworm-like forms, while the particles heat-treated at 600$^{\circ}$C showed more homogeneous morphology. The average crystalline size were 19.9∼24.nm showing an ordinary tendency to increase with the temperatures from 400 to 600$^{\circ}$C.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.444-451
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• 1987

The dependence of polarographic parameters on the pressure for the reduction of copper(II), cadmium(II), and zinc(II) complex ions with ethylenediamine, propylenediamine, and diethylenetriamine has been studied. In this study the dropping mercury electrode, the mercury pool electrode, and helix type of platinum wire were used as the working, the reference, and the auxilary electrode, respectively. With increasing the pressure from 1 atmosphere to 1,500 atmospheres, the reduction half-wave potentials of metal complex ions are shifted to the negative values and the diffusion currents become considerably larger, in keeping with the theory on the change of the physical properties of the electrolytic solution such as the density, the viscosity, the dielectric constant, and the electrical conductance, etc. The slope values of the logarithmic plot are increased with increasing the pressure, which indicates the more irreversible reduction. The temperature coefficients of diffusion current observed over the range of the temperature from 25$^{\circ}$C to 35$^{\circ}$C are about two percentage with increasing the pressure, therefore the polarographic reduction under the high pressure is controlled by diffusion. The linear relationships between diffusion current and concentration of metal complex ions are established over all pressure range.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1280-1283
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• 2005

A novel zinc complex, Zn(phen)q, was synthesized from 1,10-phenanthroline (phen) and 8-hydroxyquinoline (q) as organic ligands and its electroluminescent (EL) properties were characterized. The structure of Zn(phen)q was elucidated by FT-IR, UV-Vis and XPS. The complex Zn(phen)q showed thermal stability up to $300^{\circ}C$ under nitrogen flow, which was measured by TGA and DSC. The photoluminescence (PL) of the Zn(phen)q was measured from the THF solution and the solid film on quartz substrate. The PL emission of Zn(phen)q exhibited green light centered at about 505nm. The EL devices were fabricated by the vacuum deposition. The EL devices having the structure of ITO/a-NPD/Zn(phen)q/Li:Al were studied, where 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(a-NPD) used as a hole transport layer(HTL). a-NPD has high Tg of $96^{\circ}C$ and thus makes the device thermally stable. The EL emission of Zn(phen)q exhibited also green light centered at 532nm.