• Journal of Life Science
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• v.22 no.2
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• pp.209-219
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• 2012

The properties of lactate dehydrogenase (LDH, EC 1.1.1.27) eye-specific $C_4$ isozyme were studied by polyacrylamide gel electrophoresis, Western blotting, immunoprecipitation, and enzyme kinetics. Furthermore, we proposed the optimal conditions for measuring the activity of LDH eye-specific $C_4$ isozyme. The isozymes were detected in the cytosol of eye tissues from Lepomis macrochirus and Micropterus salmoides and were more similar to the $A_4$ than the $B_4$ isozyme. LDH/CS in the eye tissue of L. macrochirus was increased in September, so the ratio of anaerobic metabolism was high. The electrophoretic patterns of mitochondrial LDH were similar to those of cytosolic LDH in the eye tissues of L. macrochirus and Micropterus salmoides. LDH eye-specific $C_4$ isozyme from eye tissue was purified by preparative native-PAGE. The activities of LDH eye-specific $C_4$ isozymes in L. macrochirus and M. salmoides were reduced at concentrations greater than 0.2 mM and 0.1 mM of pyruvate, respectively. These concentrations remained at 5.2% and 15.8% as a result of the inhibition by 10 mM of pyruvate, so the degree of inhibition was very high. The LDH activities of eye tissues were reduced at concentrations greater than 22 mM and 24 mM of lactate, respectively, in L. macrochirus and M. salmoides. The ${K_m}^{PYR}$ of eye-specific $C_4$ was 0.088 mM in L. macrochirus and it was 0.033 mM in M. salmoides. The activities of cytosolic and mitochondrial eye-specific $C_4$ isozymes were high in ${\alpha}$-ketobutyric acid. Furthermore, the activities of eye tissue and eye-specific $C_4$ isozyme had to be measured with 0.5 mM of pyruvate and a buffer solution of pH 7.5. As a conclusion, the eye-specific $C_4$ isozyme in M. salmoides has a high affinity for pyruvate and exhibits maximum activity at a lower concentration of pyruvate and at higher concentration of lactate than that in L. macrochirus. Therefore, it seems that the energy produced by the LDH eye-specific $C_4$ isozyme in M. salmoides was used at the first stage of predatory behavior.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.324-332
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• 1985

Aspergillus niger B-15 with strong Endo-polygalacturonase (Endo-PG) activities was selected out from a total of 1,573 fungal strains isolated from various testing materials. A mutant strain, U-46, was obtained from the Aspergillus niger B-15 by repeated irradition of ultra-violet light. The objectives of the study were to investigate the fungal properties of the parental and mutant strains obtained and to study the condition of enzyme production and reaction. The results obtained are summarized as follows: 1. The size of conidial head of the U-46 mutant was smaller than that of the parental strains, B-15 and the length of the conidiophore was also shorter than that of the parental strains. 2. The optimum conditions for the Endo-PG production of the parental B-15 strain in the wheat bran Koji were obtained when 40% of water was added to the wheat bran and the temperature was 30 to $35^{\circ}C$. However, the best condition for the mutant U-46 strain was attained when 60 to 70% of water was added and the temperature was $35^{\circ}C$. The optimum growing periods were two to three days for both parental and mutant strains. 3. Under the optimum producing conditions of each strains, the enzymatic activity of the mutant U-46 was 20 times higher than the Endo-PG of the parental strain, B-15. 4. When both strains were cultured in the wheat bran Koji containing 60% of water at $35^{\circ}C$ for three days, the mutant strain. U-46, was about 46 times higher in the Endo-PG activity and about 18 times greater in Exo-PG activity than the parental strain, B-15. The activities of cellulase, $\alpha$-amylase, and glucoamylase were also highly increased in the mutant strain. 5. The mutant strain, U-46, increased its Endo-PG activity up to 20% over that of ordinary case when 1.2 to 1.5% of ammonium sulphate was added to the wheat bran. 6. The optimum condition for Endo-PG activity of crude enzyme of the mutant strain, U-46, was attained when pH of reaction solution was 4.0 to 4.5 and the temperature was $50^{\circ}C$.

• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.105-112
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• 2008

To measure the soil-to-plant transfer factors ($TF_a,\;m^2\;kg^{-1}$-fresh) of radionuclides deposited during the growing season of potato, a radioactive solution containing $^{54}Mn,\;^{60}Co,\;^{85}Sr$ and $^{137}Cs$ was applied to the soil surfaces in soil boxes 2 d before seeding and three different times during the plant growth. For the pre-seeding application (PSA), radionuclides were mixed with the topsoil (loamy sand and 5.2 in pH). The plant parts investigated were leaves, stems, tuber skin and tuber flesh. The $TF_a$ values of $^{54}Mn,\;^{60}Co,\;^{85}Sr$ and $^{137}Cs$ from the PSA were in the ranges of $1.9{\times}10^{-4}{\sim}1.5{\times}10^{-2}$, $1.8{\times}10^{-4}{\sim}7.5{\times}10^{-4}$, $4.0{\times}10^{-4}{\sim}1.6{\times}10^{-2}$, $1.5{\times}10^{-4}{\sim}3.9{\times}10^{-4}$ respectively, for different plant parts. The TFa values from the growing-time applications were on the whole a few times lower than those from the PSA. For $^{54}Mn,\;^{85}Sr$ and $^{137}Cs$, the $TF_a$ values from the early- or middle-growth-stage application were higher than those from the late-growth-stage application, whereas the opposite was true for $^{60}Co$. Leaves and tuber flesh had the highest and lowest $TF_a$ values, respectively, in most cases. The total uptake from soil by the four plant parts was in the range of $0.05{\sim}3.16%$. In the third year following the PSA, the $TF_a$ values of $^{54}Mn,\;^{60}Co$ and $^{137}Cs$ were $11{\sim}25%$, $21{\sim}25%$ and $38{\sim}67%$ of those in the first year, respectively, depending on the plant parts. The present results can be used for estimating the radiological impact of an acute radioactive deposition during the growing season of potato and for testing the validity of relevant food-chain models.

• 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.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.222-227
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• 2007

The effects of chlorine dioxide ($ClO_2$) treatment on the quality changes of pork and beef were examined. Pork belly and beef tenderloin samples were treated with 30, 50, and 100 ppm of $ClO_2$ solution, respectively, and stored at $4{\pm}1^{\circ}C$. The $ClO_2$ treatment of pork and beef during storage decreased total aerobic bacteria, yeast, and mold counts with increasing concentration of $ClO_2$. The total aerobic bacterial counts for the pork belly treated at 100 ppm of $ClO_2$ increased from 1.48 log CFU/g immediately following treatment to 4.73 log CFU/g after 10 days, while the control increased from 2.19 log CFU/g to 6.22 log CFU/g. For the beef tenderloin, the total aerobic bacterial counts increased from 3.98 log CFU/g to 5.97 log CFU/g after 10 days, and a $ClO_2$ treatment at 100 ppm resulted in an increase from 3.13 log CFU/g to 4.73 log CFU/g. The pH and volatile basic nitrogen (VBN) values of the $ClO_2-treated$ pork and beef, as well as the control groups, increased during storage, and there were no significant changes among the treatments. The thiobarbituric acid reactive substance (TBARS) values of the $ClO_2-treated$ samples were slightly higher than those of the control. Sensory evaluation results showed that the pork and beef samples were not acceptable at day 8 and 6 of storage, respectively. These results indicate that $ClO_2$ treatment could be useful in improving microbial safety and quality of both pork and beef.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.13-19
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• 2018

This study was conducted to examine the germination and growth during seedling period of Codonopsis lanceolata and Astragalus membranaceus as affected by different media. The seeds were sown in commercial medium (Tosilee), coir, rockwool, and urethane sponge. The seeds were germinated for 22 days in a closed-type plant production system, and seedlings were grown for 35 days after sowing in the venlo-type glasshouse located on Gyeongsang National University. Nutrient solution was supplied by the sub-irrigation as EC $1.0dS{\cdot}m^{-1}$ and pH 6.5 every second day. Final germination of Codonopsis lanceolata was the significantly highest in the coir and rockwool media as 68.5% and 67.9%, respectively. Mean daily germination was also the highest in the coir and rockwool media as 4.2 and 4.1, respectively. The germination rate of Astragalus membranaceus was not significantly difference in the media types. Plant height and leaf area of Codonopsis lanceolata were the significantly highest in the rockwool medium as 11.5 cm and $11.3cm^2$, respectively. Longest root length and fresh weight of root were the greatest in the coir medium as 5.8 cm and 0.07 g, respectively. Plant height and leaf area of Astragalus membranaceus were the significantly highest in the coir medium as 14.0 cm and $16.9cm^2$, respectively, and fresh and dry weights of root were the highest in the urethane sponge medium as 0.34 g and 0.03 g, respectively. Therefore, these result suggest that the rockwool and coir media were suitable for the germination and growth during seedling period of Codonopsis lanceolata and Astraglus membranaceus.

• Korean Journal of Animal Reproduction
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• v.20 no.1
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• pp.35-42
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• 1996

This study was carried out to investigate the effect of straw loading method and thawing protocol on the in vitro development of in vitro produced mouse blastocysts cryopreserved by vitrification. Three loading types of straw I, Il and III on loading and sealing method were made for vitrification. The ability of the solution on straw loading methods to remain vitreous during warming was tested by exposed in air for 1 to 10 s sec. and then plunged the vitrified straws into water bath at 25°C. Embryos to be vitrified were equilibrated to the 20% EG for 5min. and exposed in EFS 40 for 1min. The plug ends of Straw I and Straw II were sealed with straw powder and Straw III was treated straw powder, followed by heat sealing and then plunged into LN$_2$. The results obtained in these experiments were summarized as follows; 1) Straw I embryo column mostly changed from transparent to opaque upon thawing without exposure in air for 3-6 sec. Straw II embryo column was I improved partially but was not remained completely vitreous during warming. However, when Straw lll loading method was used, the embryo column was remained vitreous completely. 2) High survival rates and development rates of each groups (middle blastocysts and hatching blastocysts) of vitrified embryos were obtained by using Straw III loading method than Straw I method (P<0.05). And the range of s standard error was low in Straw lll method. 3) When the embryos vitrified-frozen were placed in air for 3, 5 and l0sec. and then warmed rapidly in water bath at 25$^{\circ}C$, the survival rates after 24h of culture were 72.7-87.1% and the development rates to hatching stage after 48h of culture were 34.0-48.4%. There were no significantly differences according to exposure time in air during warming. In conclusion, the present results showed that highly survival and low standard error of vitrified-frozen mouse bIastocysts were obtained by using straw lll loading, double sealing and appropriate 2 step warming method.

• Analytical Science and Technology
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• v.31 no.2
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• pp.96-105
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• 2018

This study aimed to improve the method for detecting eight secondary aliphatic amines (SAAs), so as to measure their concentrations in fresh water and tap water samples. NaOH (8 mL, 10 M) and benzenesulfonyl chloride (2 mL) were added to a water sample (200 mL), and the mixture was stirred at $80^{\circ}C$ for 30 min. An additional NaOH solution (10 mL) was added and the stirring was continued for another 30 min. The pH of the cooled mixture was adjusted to 5.5-6.0 by adding HCl (35 %), and the SAAs were extracted using dichloromethane (50 mL). This extraction was repeated once. The extract was then washed with $NaHCO_3$ (15 mL, 0.05 M) and dried over $Na_2SO_4$ (4 g). The extract was finally concentrated to 0.1 mL, of which $1{\mu}L$ was analyzed for SAAs by GC-MS. The linearity of the spike calibration curves was high ($r^2=0.9969-0.9996$). The detection limits of the method ranged from 0.01 to $0.20{\mu}g/L$, and its repeatability and reproducibility (expressed as relative standard deviation) were both less than 10 % (6.6-9.4 %). Its accuracy (measured in percentage error) ranged between 2.4 % and 6.1 %. The established method was applied to the analysis of five surface water and 82 tap water samples. Dimethylamine was the only SAA detected in all the water samples, and its average concentration was $0.79{\mu}g/L$ (range: $0.20-2.54{\mu}g/L$). Therefore, this study improved the analytical method for SAAs in surface water and tap water, and the regional and seasonal concentration distributions were obtained.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.237-245
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• 2014

Amur silver grass (Miscanthus sacchariflorus) and reed canary grass (Phalaris arundinacea) were selected for RDX removal experiments in hydroponic culture conditions based on vegetation survey at three shooting ranges in northern Kyunggi province. Seedling of two plants were grown in 1/4 strength Hoagland solution in quadruplicates containing 10, 20, 30, 40 mg/L RDX for 15 days along with control and blank treatments. During the 15 days of incubation, pH and RDX concentration in medium were routinely analyzed and RDX contents in the shoot and the root were determined after solvent extraction at the end of the experiments. Both plant species showed no symptoms of RDX phyto-toxicity. The pseudo first order RDX-removal constants for amur silver grass and reed canary grass were in the range of $0.0143{\sim}0.0484day^{-1}$ and $0.0971{\sim}0.1853^{-1}$, respectively. Plant biomass normalized RDX removal rates, which decreased with the increase of initial RDX concentration, were in the range of $0.27{\sim}1.01mL{\cdot}g^{-1}day^{-1}$ and $0.87{\sim}1.66mL{\cdot}g^{-1}day^{-1}$ for amur silver grass and reed canary grass, respectively. After 15 days of treatment, RDX removal from the medium decreased from 49.0% to 23.7% with increase in the initial RDX concentration in amur silver grass and 7.3% of the initial RDX remained in the plant. In reed canary grass planted medium, less than 16.8% and 5% of the initial RDX remained in the medium and in the plant, respectively. Large quantities of unidentified polar compound, which was not detected in amur silver grass, accumulated in the root and shoot of reed silver grass.

• Clean Technology
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• v.19 no.3
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• pp.219-225
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• 2013

Environment-friendly and surfactant-free aqueous cleaning agents have been developed in order to solve various problems generated by surfactants in the aqueous cleaning agents. Aqueous surfactant-free cleaning agents, S-1 and S-2 have been formulated with water-soluble solvents such as propylene glycol and propylene glycol ether on their main components and with some additives. These solvents were chosen because of their good solubility in water and excellent solubility of fluxes which are major contaminants of printed circuit board in the electronic industry. Physical properties of the formulated and the imported cleaning agents were measured to predict their cleaning performance, and their cleaning abilities of flux and solder contaminants were evaluated under the various ultrasonic frequencies by a gravimetric method. The measurement results show that the physical properties of cleaning agent V are generally similar with those of formulated cleaning agents S-1 and S-2. Both the cleaning agent V and the formulated cleaning agents S-1 and S-2 showed similar trends that their pH decrease in the beginning and then increases later on with the increase of their dilution in water. It is considered that the wetting indices of the cleaning agents calculated with experimental values do not not have any influence on their cleaning ability. In ultrasonic cleaning tests under three ultrasonic frequencies of 28, 45, and 100 kHz, their best performances of cleaning solder and flux were obtained at 45 kHz and 28 kHz, respectively, and the cleaning performance of the formulated cleaning agents S-1 and S-2 was better than that of the cleaning agent V. However, in the case of the recommended diluted concentration of 25 wt% cleaning solution, the cleaning performance of the cleaner V for solder and flux was better in the initial stage of cleaning compared to the formulated cleaners. And it may be concluded that the formulated cleaning agents S-1 and S-2 can be applied to cleaning of solder and flux in the industry, based on the experimental results in this study.