• Journal of Microbiology
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• 제33권2호
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• pp.109-114
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• 1995

Alkalophilic Cephalosporium sp. RYM-202 produced multiple xylanases extracellularly. One of these xylanases was purified to electrophoretical homogeneity by chromatography with DEAE-Sephadex A-50, Sephacryl S-200 HR and Superose 12 HR. The purified xylanase differed from most other microbial xylanases in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase was 23 kDa by SDS-polyacrylamide electrophoresis and 24 kDa by gel permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permentation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity at pH 8.0 and 50 .deg.C. It was stable over a wide range of pH and retained more than 80% of its original activity after 24 h of incubation even at pH 12. The Km values of this enzyme on birchwood xylan and oat spelts xylan were 2.33 and 3.45 mg/ml, respectively. The complete inhibition of the enzyme of n-bromosuccinimide suggests the involvement of tryptophan in the active site. The sylanase lacked activity towards crystalline cellulose and carboxymethyl cellulose.

• BMB Reports
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• 제28권2호
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• pp.138-142
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• 1995

An anticoagulant/fibrinolytic protease was purified to homogeneity from the earthworm Lumbricus rubellus. The protein was a single chain glycoprotein of 32 kDa that exhibited strong proteolytic activity on human thrombin and fibrin clots. Proteolytic degradation of these plasma proteins by the purified enzyme occurred at a neutral pH range. Among several human plasma proteins tested as possible substrates for the protease reaction, the 32 kDa enzyme specifically hydrolyzed both thrombin and fibrin polymers without affecting other proteins, such as serum albumin, immunoglobulin, and hemoglobin. Treatment of the purified enzyme at neutral pH with either phenylmethylsulfonylfluoride or soybean trypsin inhibitor resulted in a loss of catalytic activity. The enzyme hydrolyzed the chromogenic substrate H-D-Phe-L-Pipecolyl-L-Arg-p-nitroanilide with a $K_m$ value of 1.1 ${\mu}M$ at a neutral pH. These results suggest that the anticoagulant/fibrinolytic enzyme from Lumbricus rubellus is a member of the serine protease family having a trypsin-like active site, and one of the potential clevage sites for the enzyme is the carbonyl side of arginine residues in polypeptide chains.

• 미생물학회지
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• 제29권2호
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• pp.104-110
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• 1991

The glucoamylase of Schwanniomyces castellii was purified to homogeneity from the culture filtrate. the purified enzyme was a glycoprotein with a molecular mass of about 145 KDa, which was monomeric protein with an isoelectric point of 4.3. The pH and temperature optima were 5.5 and 40.deg.C, respectively. The enzyme was fairly stable up to 50.deg.C and at acid pH range (pH 4.5-6.0). The apparent Km of the enzyme toward soluble starch, isomaltose and pullulan were 3.84, 0.51 and 13.7 mg/ml, respectively. The analysis of amino acid composition on this enzyme was found to be acidic protein like other fungal glucoamylase. The amino acid sequence of N-terminal peptide consisted of Ala-Pro-Ala-Asp-Gly-Ile-Gly-Asp-X-Ala-X-Ala.

• 한국세라믹학회지
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• 제38권4호
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• pp.307-307
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• 2001

Combustion process with citrate was used to produce the LiMn$_2$O$_4$powder. Precursors are pre-ignited in open air followed by post-heating in the range from $600^{\circ}C$ to 80$0^{\circ}C$ for 4h. With varying the molar ratio (R) of ethylene glycol (EG) to citric acid (CA) from 0 to 4, the effect of EG content on powder characteristics is evaluated. Vacuum drying promote the auto-ignition at room temperature. With small addition of EG metal ion was selectively segregated with organic substances and undesired lithium evaporation occurred during post-heating. LiMn$_2$O$_4$phase which is produced by combustion reaction was decomposed back to Mn$_3$O$_4$because the reaction temperature was higher than 95$0^{\circ}C$. With increasing EG content, the homogeneity of LiMn$_2$O$_4$powder increased and specific surface area increased. And lithium evaporation during vacuum drying and/or ignition also increased.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.242-250
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• 2001

A Gram-positive bacterium (strain JB-13) that was isolated from soil as a producer of cyclodextrin glucanotransferase (CGTase) [EC 2.4.1.19] was identified as Panibacillus sp. JB-13. This CGTase could catalyze the transglucosylation reaction from soluble starch to L-ascorbic acid (AA). A main product formed by this enzyme with ${\alpha}-glucosidase$ was identified as $2-O-{\alpha}-D-glucopyranosyl{\;}_{L}-ascorbic$ acid (AA-2G) by the HPLC profile and the elemental analysis. CGTase was purified to homogeneity using ammonium sulfate fractionation, ion-exchange chromatography on DEAE-Seohadex A-50, and gel chromatography on Sephacryl S-200HR. The molecular weight was determined to be 66,000 by both gel chromatography and SDS-PAGE. The isoelectric point of the purified enzyme was 5.3. The optimum pH and temperature was PH 7.0 and $45^{\circ}C$ respectively. The enzyme was stable in the range of pH 6-9 and at temperatures of $75{\circ}C$ or less in the presence of 15 mM ${CaCl_2}.\;{Hg^2+},\;{Mn^+2},{Ag^+},\;and\;{Cu^2+}$ all strongly inhibited the enzyme's activity.

• 한국농림기상학회지
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• 제7권1호
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• pp.4-14
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• 2005

CarboKorea and HydroKorea are the domestic projects aiming to improve our understanding of carbon and water cycles in a typical Korean forest located in a complex terrain with a watershed connected to large rivers. The ultimate goal is to provide a nowcasting of these cycles for the whole Peninsula. The basic strategy to achieve such goal is through the inter- and multi-disciplinary studies that synthesize the in-situ field observation, modeling and remote sensing technology. The challenge is the fact that natural ecosystems are nonlinear and heterogeneous with a wide range of spatio-temporal scales causing the variations of mass and energy exchanges from a leaf to landscape scales. Our paradigm now shifts from temporal variation at a point to spatial patterns and from spatial homogeneity to complexity of water and carbon at multiple scales. Yet, a large portion of our knowledge about land-atmosphere interactions has been established based on tower observations, indicating that the development of scaling logics holds the key to the success of CarboKorea and HydroKorea. Here, we review the pioneering work of FIFE (First ISLSCP Field Experiment) on scaling issues in a temperate grassland and discuss the lessons from it for the application to Gwangneung forest site.

• Journal of Microbiology
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• 제35권2호
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• pp.134-140
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• 1997

Botrytis cinerea T91-1 has been shown to produce at least four different polygalacturonases into a liquid medium containing citrus pectin, a carbon sousrce. One of the enzymes, which had an apparent molecular weight of 66 kDa estimated by denatured polyacrylamide gel electrophoresis, was purified to electrophoretic homogeneity by a series of procedures including a cetone precipitation, ion exchange, heparin affinity, and reverse phase column chromatographies. The molecular weight of native enzyme was determined to be 64 kDa by gel permeation chromatography indicating the enzyme to be a single polypeptide chain. By viscometric analysis, the enzyme was revealed as exo-polygalacturonase. The enzyme activity was inhibited by divalent cations such as $Ca^{2+}$, $Mg^{2+}$, and Cu$^{2+}$. Km and Vmax for polygalacturonic acid hydrolysis were 0.33 mg/ml and 28.6 nM/min, respectively. The optimum temperature for enzymatic activity was 5$0^{\circ}C$. And the enzyme showed optimal pH values between 4.0 and 5.0. The enzyme was stable upto 12 hours in the range of pH 3 to 8 and at temperature below 3$0^{\circ}C$.

• 한국환경과학회지
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• 제11권9호
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• pp.829-842
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• 2002

The purpose of this study was to design a reliable and valid Likert-type scale to measure nuclear energy attitudes of various groups. 8 tests were applied to the construction of a 26-item long form, a 12-item middle form, and a 6-item short form of the scale. Three scales were field tested on 760 respondents representing a diverse range of subjects. The 26-item scale appeared to be reliable, content valid and construct valid. Scale reliability and homogeneity were evidenced by 0.95 coefficient alpha and positive interitem correlations ranging from 0.18 to 0.74. The results of factor analysis and known-groups comparison revealed that this scale had high validity. Reliability of the middle form and short form were evidenced by coefficient alpha of 0.92 and 0.90 respectively. The long and middle forms were strongly correlated, r-value of 0.98 and the long and short forms were also highly correlated, r-value of 0.93. Consequently, long form, middle form and short form scales were evidenced very reliable and valid in measuring nuclear energy attitudes of various groups in general. They can be used for a variety of purpose of measuring and testing nuclear energy attitude.

• 한국세라믹학회지
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• 제31권7호
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• pp.804-812
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• 1994

Stable PZT coating sol was prepared using chelating agent, ethylacetoacetate(EAcAc) by sol-gel processing under ambient atmosphere. Through FT-IR spectrum analysis on solution of each reaction step, formation of metal complex was confirmed and prepared PZT sol was stable over several months. Through TG-DTA, XRD, FT-IR spetrum analysis of PZT gel powder, it was understood that the addition of EAcAc could reduce the transition temperature to ferroelectric phase, due to the increased homogeneity by matching the hydrolysis and condensation rates by chelation. Single perovskite phase was obtained by the heat-treatment at 54$0^{\circ}C$ for 30 min. The film was coated on ITO-coated glass substrate by dip coating method. After heat-treatment, PZT thin film had thickness in the range of 20~130 nm. The maximum dielectric constant of its thin film at room temperature and 1 kHz was 128.

• Fibers and Polymers
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• 제4권1호
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• pp.20-26
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• 2003

The thermal behavior, morphology, ester-interchange reaction of Poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) melt blends were investigated over the whole composition range(xPTT/(1-x)PET) using a twinscrew Brabender. The melt blends were analyzed by differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy ($^{13}{C-NMR}$), and scanning electron microscopy (SEM). Single glass transition temperature ($T_g$) and cold crystallization temperature ($T_cc$) were observed in all melt blends. Melt blends were found to be due to the ester-interchange reaction in PTT/PET blend. Also the randomness of copolymer increases because transesterification between PT and PET increases with increasing blending time This reaction increases homogeneity of the blends and decreases the degree of crystallinity of the melt blends. In PTT-rich blends, mechanical properties decrease with increase of PET content compared with that of pure PTT. And, in PET-rich blends, tensile modulus decreases with increase of PTT content, but tensile strength and elongation is similar to that of pure PET.