• The Korean Journal of Mycology
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• v.31 no.2
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• pp.59-66
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• 2003

Laccase produced by Pycnoporus cinnabarinus SCH-3 isolated from Korea was partially purified using ultrafiltration, anion exchange chromatography and affinity chromatography, The laccase was produced as the predominant extracellular phenoloxidase during primary metabolism. Neither lignin peroxidase nor manganese-dependent peroxidase were detected in the culture fluid. In order to examine the effect of inducers in laccase production, 2,5-xylidine was added in the culture of Pycnoporus cinnabarinus SCH-3. Addition of 2,5-xylidine enhanced 25-fold laccase production. Purified laccase was a single polypeptide having a molecular mass of approximately 66 kDa, as determined by SDS-polyacrylamide gel electrophoresis, and carbohydrate content of 9%. $K_{m}\;and\;V_{max}$ values for laccase with ABTS [2,2-azinobis (3-ethylbenzthiazoline 6-sulfonic acid)] as a substrate (Lineweaver-Burk plot) was determined to be $44.4{\mu}M\;and\;56.0{\mu}mole$, respectively. The optimal pH for laccase activity was found to be 3.0. The enzyme was very stable for 1 hour at $60{\circ}C$. Half-life ($t_{1/2}$) of the enzyme was about 10 min at $80{\circ}C$. Spectroscopic analysis of purified enzyme indicated that the enzyme was typical of copper-containing protein. Substrate specificity and inhibitor studies for laccase also indicated to be a typical fungal laccase. The N-terminal amino acid sequence of the P. cinnabarinus SCH-3 laccase showed 94% of homology to the N-terminal sequences of laccases from P. cinnabarinus PB and P. coccineus.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.215-225
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• 1996

Aseptic meningits, an acute inflammation of the meninges, is a common illness during childhood. Virus is the most important cause of aseptic meningitis. Especially enterovirus causes approximately above 85% of all cases of aseptic meningitis. In 1993, there was a big epidemic of aseptic meningitis by ECHO 9 and ECHO 30 viruses. And ECHO 3 virus was isolated as a causative agent of aseptic meningitis in 1994. This study was aimed to detect the causative agent of aseptic meningitis in 1995 and to analyze the 5'-noncoding region which was used to detect virus. Virus was isolated from 87 stools and cerebrospinal fluid specimens of the patients by cultured RD and HEp-2 cell. Neutralizing antibody tests using enterovirus serum pool were performed on the specimens with cytopathic effect. 3 of ECHO 7 viruses and 5 of Coxsackie B3 viruses were isolated from stool specimens and 1 of ECHO 7 and Coxsackie B3 mixed type was confirmed from cerebrospinal fluid specimens. RNA was isolated from the culture supernatants of infected cells and general primers were selected in highly conserved part of the 5'-noncoding region of the enteroviral genome for RT-PCR. PCR product from this virus showed a 152bp band on gel electrophoresis. Sequence of obtained DNA was compared with prototype sequences by accessing to the Genebank database. 5'-noncoding region of isolated Coxsackie B3 virus, which has point mutations in nucleotide sequence positions 493, 497, 502, 523, was closely related to that of polio virus type 1, Mahoney strain. In case of isolated ECHO 7 virus, nucleotide has been changed from cytosine to thymine at position 581 and from thymine to cytosine at position 583. We concluded the causative agents of the outbreak of aseptic meningitis during June to July in 1995 were both ECHO 7 and Coxsackie B3 virus, and the primer used in this study could allow a rapid diagnosis of enteroviruses by PCR.

• Journal of Life Science
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• v.27 no.2
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• pp.202-210
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• 2017

As an effort to find a potential biopreservative, we isolated bacterial strains producing bacteriocin from fermented foods. A strain was finally selected and characteristics of the bacteriocin were investigated. The selected strain was identified as Bacillus subtilis E9-1 based on the 16S rRNA gene analysis. The culture supernatant of B. subtilis E9-1 showed antimicrobial activity against Gram-positive bacteria. Subtilisin A, ${\alpha}$-chymotrypsin, trypsin and proteinase K inactivated the antimicrobial activity, which means its proteinaceous nature, a bacteriocin. The bacteriocin activity was fully retained at the pH range from 2.0 to 8.0 and stable at up to $100^{\circ}C$ for 60 min. Solvents such as ethanol, isopropanol and methanol had no effect on the antimicrobial activity at the concentration of 100% but acetone and acetonitrile reduced the activity at up to 100% concentration. Cell growth of four indicator strains was dramatically decreased in dose-dependent manner. Listeria monocytogenes was the most sensitive, but Enterococcus faecium was the most resistant. Bacillus cereus and Staphylococcus aureus showed the medium sensitivity. The bacteriocin showed its antimicrobial activity against B. cereus and L. monocytogenes via bactericidal action. The number of viable cells of L. monocytogenes started to reduce after addition of bacteriocin to the minced beef. The bacteriocin was purified through acetone concentration, gel filtration chromatography and RP-HPLC. The whole purification step led to a 6.82 fold increase in the specific activity and 6% yield of bacteriocin activity. The molecular weight of the purified bacteriocin was determined to be 3.3 kDa by MALDI-TOF/TOF mass spectrometry.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.45-50
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• 2015

The goal of this research is the create novel magnets with no rare-earth contents, with larger energy product by comparison with currently used ferrites. For this purpose we developed nano-sized hard-type/soft-type composite ferrite in which high remanent magnetization (Mr) and high coercivity (Hc). Nano-sized Ba-ferrite, Ni-Zn ferrite and $BaFe_{12}O_{19}/Ni_{0.5}Zn_{0.5}Fe_2O_4$ composite ferrites were prepared by sol-gel combustion method by use of glicine-nitrate and citric acid. Nanocomposite ferrites were calcined at temperature range $700-900^{\circ}C$ for 1h. According to the X-ray diffraction patterns and FT-IR spectra, single phase of NiZn-ferrite and Ba-ferrite were detected and hard/soft nanocomposite ferrite was indicated to the coexistence of the magnetoplumbite-structural $BaFe_{12}O_{19}$ and spinel-structural $Ni_{0.5}Zn_{0.5}Fe_2O_4$ that agreed with the standard JCPDS 10-0325 data. The particle size of nanocomposite turn out to be less than 120 nm. The nanocomposite ferrite shows a single-phase magnetization behavior, implying that the hard magnetic phase and soft magnetic phase were well exchange-coupled. The specific saturation magnetization ($M_s$) of the nanocomposite ferrite is located between hard ($BaFe_{12}O_{19}$) and soft ferrite($Ni_{0.5}Zn_{0.5}Fe_2O_4$). The remanence (Mr) of nanocomposite ferrite is much higher than that of the individual $BaFe_{12}O_{19}$ and $Ni_{0.5}Zn_{0.5}Fe_2O_4$ ferrite, and $(BH)_{max}$ is increased slightly.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.11-17
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• 2012

Disinfection of Escherichia coli (E. coli) in drinking water was investigated by using $TiO_2$ and $TiO_2-SiO_2$ based photocatalyst prepared by sol-gel method. The disinfection test was carried out in an annular flow reactor with circulating sterile water containing the photocatalysts powder under UV-A irradiation. The disinfection activity was proportional to the anatase`s intensity of crystalline peak of the $TiO_2$ photocatalysts. 100% disinfection of E.coli without endotoxin was achieved with $TiO_2$ coated photocatalytic system under UV-A irradiation within 2 h. However, toxic endotoxine was exist in the disinfection of E.colithe under UV-C irradiation even though 100% disinfection of E.colithe within 30 min, which suggest that $TiO_2$ coated photocatalytic system with UV-A is useful tool for the disinfection of E.coli in drinking water.

• Journal of the Korean Magnetics Society
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• v.24 no.3
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• pp.81-85
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• 2014

Nano-sized Ba-ferrite, Ni-Zn ferrite and $BaFe_{12}O_{19}/Ni_{0.5}Zn_{0.5}Fe_2O_4$ nanocomposite ferrite were prepared by sol-gel combustion method. Nanocomposite was calcined at temperature range of $600{\sim}900^{\circ}C$ for 1 h. According to the diffraction patterns, hard/soft nanocomposite was indicated to the coexistence of the magnetoplumbite structural $BaFe_{12}O_{19}$ and spinel $Ni_{0.5}Zn_{0.5}Fe_2O_4$ and agree with the standard data (JCPDS 10-0325). The particle size of nanocomposite turn out to be less than 90 nm. The nanocomposite ferrite shows a single-phase magnetization behavior, implying that the hard magnetic phase and soft magnetic phase were well exchange-coupled. The specific saturation magnetization ($M_s$) of the nanocomposite is located between hard ($BaFe_{12}O_{19}$) and soft ferrite ($Ni_{0.5}Zn_{0.5}Fe_2O_4$). The remanence (Mr) of nanocomposite ferrite is much higher than that for the individual $BaFe_{12}O_{19}$ and $Ni_{0.5}Zn_{0.5}Fe_2O_4$ ferrite. $(BH)_{max}$ is increased, generally.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.66-72
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• 2009

Diabetic Retinopathy (DR) is a leading cause of blindness among adults in the western countries. Hyperglycemia is a condition, that induces apoptotic cell death in a variety of cell types in diabetes, but the mechanism remains unclear. The aim of the study is to understand the effects of high Glucose on Human Retinal Endothelial Cells. Retinal endothelial cells were cultured in Iscove's Modified Dulbecco's Medium (IMDM) containing 5, 25 and 50 mM Glucose, incubated for 24, 36 and 48 hours in humidified 5 % CO$_2$ incubator at 37$^{\circ}C$. Human Retinal Endothelial Cell Line (HREC) were characterized for morphology with different treatment by phase contrast microscopic analysis. Number of dead and viable cells was counted by trypan blue exclusion and supported by MTT assay. The intracellular Hydrogen peroxide (H$_2$O$_2$), a Reactive Oxygen Species (ROS) generation in high glucose conditions was assessed by FOX II assay and apoptosis by caspase-3 assay. The high glucose treated cells undergoing DNA fragmentation was witnessed by Agarose gel electrophoresis. We found that the cells incubated with 25 and 50 mM glucose containing medium for 48 hours altered the morphology of the cell, induced apoptosis and DNA fragmentation. The dead cell number were high in 25 and 50 mM when compared to the cells incubated with 5 mM glucose for 24, 36, and 48 hours. Also, the H$_2$O$_2$ levels and the activity of caspase-3 were increased in high glucose treated cells. Conclusions/interpretation: Our results demonstrated that elevated glucose induces apoptosis in cultured HREC. The hyperglycemia-induced increase in apoptosis may be dependent on caspase activation. The association between ROS generation and caspase-3 activation on high glucose treated cells is yet to be investigated.

• Applied Biological Chemistry
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• v.23 no.1
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• pp.23-30
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• 1980

Labelling of chromatin proteins with 32P was observed after incubating isolated liver nuclei with $[{\gamma}-32P]$ ATP for 5 minutes at $37^{\circ}C$. The pattern of labelling with 32P was examined on SDS polyacrylamide gel electrophoresis with nuclei from rats maintained in a starvation state for 48 hours, following refeeding for 12 hours; and from fed streptozotocin-diabetic rats with insulin injection 6 hours before sacrifice. With 48h starved rat liver nuclei the level of phosphorylation for 0.14M NaCl soluble proteins was decreased in the molecular weights between 41,000 and 200,000 daltons relative to normal controls. Refeeding the starved rats reversed the change of phosphorylation pattern over 12 hour The level of phosphorylation for five phenol soluble non-histone proteins with molecular weights above 59,000 daltons was somewhat decreased with 48h starved rat liver nuclei as compared with that of normal controls. Starvation also decreased the phosphorylation level of major histones in relation to normal controls. The experiment with insulin injection into fed streptozotocin-diabetic rats showed the tendency to increase phosphorylation of 0.14M NaCl soluble proteins (130,000 dalton protein) and phenol soluble non-histone proteins (155,000 dalton protein). The phosphorylation level of histones appeared to be invariant under the experimental conditoins employed here. These results suggest the possibility that the phosphorylation and dephosphorylation of 0.14M NaCl soluble proteins and $H_1$ histone precede those of other chromatin associated nuclear proteins, It is of interest to find that insulin signal was correlated to phosphorylation of nuclear proteins while glucagon signet dephosphorylated nuclear proteins.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.65-71
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• 1994

Chungkook-Jang was produced by fermenting Bacillus licheniformis CN-115. The changes of chemical composition, enzyme activity, and amino acids during the fermentation were investigated. The proximate composition was shown irregular fluctuation phenomenon during the fermentation, but only the moisture tended some reducing during the fermentation just after steaming. The content of amino nitrogen was increased radically after the 36 hours of fermentation and became the highest level at 18.072 mg/g at the 60 hours of it. In accordance with the fermentation of Chungkook-Jang, pH got to the 8.39 at 60 hours with increasing, protease activity was increased according to the fermentation and acid and neutral protease activity was reduced after being reached at the highest activity at 48 hours. The most suitable pH was 6.5 and temperature was $35^{\circ}C$ for dissolution-activated of protein in the process of fermentation of Chungkook-Jang. The content of water soluble protein and the content of salt soluble protein were increased at continuously according to the fermentation time of Chungkook-Jang the largest quantity. The molecular weight of water soluble protein of Chungkook-Jang fermented for 48 hours was about 19,000. The amino acids of water soluble protein just after steaming were totally 16 kinds and proline was amino acid and them was in series by glutamic acid and serine in that ordered. The amino acids salt soluble protein, just after steaming were totally 16 kinds and was the largest quantity phenylalanine, glutamic acid and aspartic acid and aspartic acid in that order.

• Journal of Life Science
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• v.25 no.9
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• pp.1027-1035
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• 2015

A strain GP32 which produces a highly viscous extracellular polysaccharide was conducted with soil samples and identified as Pseudomonas species. The culture flask conditions for the production of extracellular polysaccharide by Pseudomonas sp. GP32 were investigated. The most suitable carbon and nitrogen source for extracellular polysaccharide production were galactose and (NH₄)₂SO₄. The optimum carbon/nitrogen ratio for the production of extracellular polysaccharide was around 50. The optimum pH and temperature for extracellular polysaccharide production was 7.5 and 32℃, respectively. In batch fermentation using a jar fermentor, the highest extracellular polysaccharide content (15.7 g/l) was obtained after 70 hr of cultivation. The extracellular polysaccharide produced by Pseudomonas sp. GP32 (designated Biopol32) was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography. Biopol32, which has an estimated molecular weight of over 3×10⁷ datons, is a novel polysaccharide derived from sugar components consisting of galactose, glucose, gulcouronic acid and galactouronic acid in an approximate molar ratio of 1.85 : 3.24 : 1.00 : 1.42. The solution of Biopol32 showed non-Newtonian characteristics. The viscosity of Biopol32 exhibited appeared to be higher at all concentration compared to that of zooglan from Zoogloea ramigera. An analysis of the flocculating efficiency of Biopol32 in industry wastewater (food, textile, and paper wastewater) revealed chemical oxygen demand (COD) reduction rates 58.4-67.3% and suspended solid (SS) removal rates 82.6-91.3%. Based on these results, Biopol32 is a possible candidate for industrial applications such as wastewater treatment.