• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.156-158
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• 2009

Purpose: Since radiopharmaceuticals are intended for human administration, it is imperative that we should undergo quality control very strictly. Now almost all the PET laboratories have adopted Bacterial Endotoxin Test as the stand quality control method to monitor whether pyrogen is free or not in the product vial containing crude solution. The aim of this study is to find out the reason why false positive result is observed when using commercially available test vial. Materials and Methods: For this experiment, we used commercially available single test kit (Associates of Cape Code. Inc. USA) and we made pH samples by mixing each buffer whose pH ranges are 1.0 to 12.0. Otherwise we made Ethanol samples diluted with distilled water. After making test samples, it added 0.2 mL to the test vial. Assay mixture in the test vial was incubated in a water bath (Chang Shin Co. KOR) for 60 min at $35{\pm}2^{\circ}C$. Results: After incubation period ($60{\pm}1^{\circ}C$), we inverted the test vial about $180^{\circ}$ To know what pH and how many percentage of Ethanol (Fisher Scientific Korea. Ltd) will affect the reaction. With pH buffer, false positive result was observed at pH 1.0 to 5.0 and 7.7 to 12.6 but at pH 5.2 to.7.5, the test results show negative. It's very strange that we couldn't observe negative test result with Tris buffer at pH 8.4, 8.6, 8.8, 9.0. in other case Ethanol, the test result was seen with 5 to 10% Ethanol. But to my surprise we could see very thick gel formation with 100% Ethanol. Conclusions: In this study, we could notice that pH which is too much acidic or alkalic or high concentrated Ethanol would affect Bacterial Endotoxin Test result. As you know, LAL test is sensitive and very reliable method. Therefore, we are needed to elicit the accurate test result as possible as we can.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1574-1582
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• 2020

Flavonoids have diverse biological functions in human health. All flavonoids contain a common 2-phenyl chromone structure (C6-C3-C6) as a scaffold. Hence, in using such a scaffold, plenty of high-value-added flavonoids can be synthesized by chemical or biological catalyzation approaches. (2S)-Naringenin is one of the most commonly used flavonoid scaffolds. However, biosynthesizing (2S)-naringenin has been restricted not only by low production but also by the expensive precursors and inducers that are used. Herein, we established an induction-free system to de novo biosynthesize (2S)-naringenin in Escherichia coli. The tyrosine synthesis pathway was enhanced by overexpressing feedback inhibition-resistant genes (aroG^fbr and tyrA^fbr) and knocking out a repressor gene (tyrR). After optimizing the fermentation medium and conditions, we found that glycerol, glucose, fatty acids, potassium acetate, temperature, and initial pH are important for producing (2S)-naringenin. Using the optimum fermentation medium and conditions, our best strain, Nar-17LM1, could produce 588 mg/l (2S)-naringenin from glucose in a 5-L bioreactor, the highest titer reported to date in E. coli.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.895-902
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• 2014

Bacterial cellulose (BC) has played important role as new functional material for food industry and industrial products based on its unique properties. The interest in BC from static cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. In this study, we investigated culture condition for BC production by Acetobacter sp. F15 in static culture. The strain F15, which was isolated from decayed fruit, was selected on the basis of BC thickness. The optimal medium compositions for BC production were glucose 7%, soytone 12%, $K_2HPO_4$ 0.2%, $NaH_2PO_4{\cdot}_2H_2O$ 0.2%, lactic acid 0.05% and ethanol 0.3%, respectively. The strain F15 was able to produce BC at $26^{\circ}C-36^{\circ}C$ with a maximum at $32^{\circ}C$. BC production occurred at pH 4.5-8 with a maximum at pH 6.5. Under these conditions, a maximum BC thickness of 12.15 mm was achieved after 9 days of cultivation; this value was about 2.3-fold higher than the thickness in basic medium. Scanning electron micrographs showed that BC from the optimal medium was more compact than plant cellulose and was reticulated structure consisting of ultrafine cellulose fibrils. BC from the optimal medium was found to be of cellulose type I, the same as typical native cellulose.

• Journal of Life Science
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• v.25 no.4
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• pp.450-455
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• 2015

This study compared the heavy metal contents and the effects of extracts from domestic and imported red sea bream on the antioxidant activity and cytotoxicity of human cancer cell lines. The antioxidant activity was measured using the fluorescently sensitive dye, 2’-7’ dichlorofluorescein-diacetate (DCFH-DA), and antiproliferative activity against AGS human gastric adenocarcinoma and HT-29 human colon cancer cell lines, which was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Domestic red sea bream had a higher mercury content when compared to imported red sea bream, but there was no significant difference in the lead content. Treatments with acetone/methylene chloride (A+M) and methanol (MeOH) extracts from domestic and imported red sea bream dose-dependently decreased the H₂O₂ induced ROS production, compared to the control. The cell viability showed that treatments with the A+M and MeOH extracts had cytotoxicity in the growth of AGS and HT-29 cancer cells. In the case of AGS, the extracts from the domestic red sea bream were higher in inhibiting cancer cell growth, compared to imported red sea bream. Our results demonstrate that the heavy metal contents of domestic and imported red sea bream were below the limit of the Food Code of Korea. The results of the biological activities indicate that the antioxidant activity of extracts from imported red sea bream was more effective, while the extracts from the domestic red sea bream were stronger in cytotoxic activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.272-277
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• 2010

This experimental study was performed to investigate the antitumor effect of Egg white combined-Chalcanthite (InSan 4, IS4) in xenografted nude mice with NCI-H460 human lung cancer cell. We cultured NCI-H460 cell lines and xenografted them on nude mice. These mice were divided into 3 groups; group with dose of 45 mg/kg IS4 orally, group with dose of 90 mg/kg IS4 orally, and the control group. They had been raised and treated for 28 days. We checked their body weight, tumor weight and volume twice a week, and their absolute organ weight, microhistological observation and biochemical blood analysis at the final day by sacrificing them. We also calculated their tumor inhibition rate (IR), mean survival time and percent increase in life span (% ILS). In this study, we observed that all of the IS4 treated mice have tumor regression, dosage-dependently, compared to the control group. Tumor weight and volume of high dose treated mice were smallest. IR increased in IS4 in a dose-dependent manner. Mean survival time and percent increase in life span (% ILS) in high-dose IS4 treatment group were the highest of the three groups. There was no significant difference in biochemical blood analysis, alanine phopsphatase (ALP), Calcium, creatinine (CRE), alanine transferase (ALT), and aspartate transaminase (AST) levels. The urea nitrogen (UN) level results significantly decreased by IS4 45 and 90 mg/kg (IS4 45 mg/kg, IS4 90 mg/kg, p<0.01). IS4 may have potential anti-tumor effect in a solid tumor induced by NCI-H460 without remarkable side effects.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.69-75
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• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.567-573
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• 2001

Lactobacilli have been generally recognized as an important lactic acid bacteria present in the normal human intestinal flora. Fifty two Lactobacillus isolates were recovered from the feces of healthy Koreans whose age ranged from thirteen days after birth to 37 years. Among the isolates above, 17 isolates were tentatively identified as strains of Lactobacillus acidophilus and 3 isolates as strains of Lactobacillus casei. For their characterization, these twenty isolates were subjected to the experiments for the resistance to the artificial gastric juice, pH2.5 and bile salt. Interestingly, 3 strains survived pH 2.5 after 3 hour incubation in the artificial gastric juice with more than 75% of survival rate. L. acidophilus a-4 had the highest survival rate of 100%. Four strains including L. acidophilus a-3 grew gradually in MRS broth in the presence of the artificial bile salt. Cholesterol assimilation was also tested for the 20 isolates. The result showed that cholesterol concentration of the medium was reduced by 10 Lactobacillus isolates with more than 60%, as compared to the control. L. acidophilus a-2 had the highest reduction rate of 77%. Judging from these data obtained in vitro, some isolates ware likely to reach the lower small intestine after consumption without a significant loss of viability, suggesting that they had the potential to be developed as a probiotic culture which might lower the cholesterol level in human.

• Analytical Science and Technology
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• v.20 no.4
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• pp.323-330
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• 2007

A simple and rapid HPLC method with fluorescence detection(FLD) for quantitation of penciclovir in human plasma using a monolithic column was developed and validated. Penciclovir and ganciclovir(internal standard, I.S.) were separated on a Chromolith column RP-18e ($4.6{\times}100mm$) with a mobile phase consisting of a mixture of (A) methanol/50 mM sodium phosphate buffer containing 200 mg/L sodium dodecyl sulfate (3/97, pH 2.5) and (B) methanol/50 mM sodium phosphate buffer containing 200 mg/L sodium dodecyl sulfate (50/50, pH 2.5) at a flow gradient of $1.6{\sim}4.0mL/min$. The retention times of penciclovir and internal standard were less than 4.0 min. Calibration curve was linear ($R^2=0.9994$) over a concentration range of $0.1{\sim}5{\mu}g/mL$. Intra-day precision, accuracy and inter-day precision were 1.36~8.55 %, 92.8~100.0 % and 0.93~5.62 %, respectively with a limit of quantitation at $0.1{\mu}g/mL$. The present HPLC-FLD method is sensitive, precise and accurate. The method described herein has been successfully used for the bioequivalence study of a famciclovir formulation product after oral administration to healthy Korean volunteers.

• Hwankyungkyoyuk
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• v.14 no.2
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• pp.15-27
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• 2001

The purpose of this study is to understand and compare the characteristics of the content organization system of three Environment textbooks currently used, and to examine its connectivity with the teaching & teaming methods included in the Environment subject part of the 7th Korean National Curriculum. For the analysis three Environment textbooks for middle school and their teacher's guide books by three companies. published(A, B, and C) The result of the taxonomic analysis showed that three Environment books had different steps to get to the lesson class unit in the way that A of six steps, B of five steps and C of seven steps. The amount of main text was different In the domains of'Human and Environment','Environmental Problems and its Counter-plan'and'Environmental Conservation'of three textbooks each. All of three textbooks had the biggest percentage in sub-domains of'Living Environment to Keep'and'Global Environmental Problem'in 'Environmental Problems and its Counter-plan'domain. Considering teaching & loaming methods all of three textbooks contained many activities as 55 in A, 66 in H and 91 in C. Among 9 teaching 8E teaming methods and others listed in the Environment subject part of the 7th Korean National Curriculum, the investigation method is most frequently used in all of three textbooks. The drama, the paly and the case study were used rarely as teaching & teaming methods in activities In the consideration of the content amount regarding academic fields, it was revealed that three textbooks overemphasized the aspect of natural sciences comparing the aspect of human & social sciences aspect as a whole. Generally the appendix section of all three textbooks were well organized to support the teaching and teaming activities in main text.

• Molecules and Cells
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• v.27 no.3
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• pp.337-343
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• 2009

We developed a novel on-chip activity assay using protein arrays for quantitative and rapid analysis of transglutaminase activity in mammalian cells. Transglutaminases are a family of $Ca^{2+}$-dependent enzymes involved in cell regulation as well as human diseases such as neurodegenerative disorders, inflammatory diseases and tumor progression. We fabricated the protein arrays by immobilizing N,N'-dimethylcasein (a substrate) on the amine surface of the arrays. We initiated transamidating reaction on the protein arrays and determined the transglutaminase activity by analyzing the fluorescence intensity of biotinylated casein. The on-chip transglutaminase activity assay was proved to be much more sensitive than the $[^3H]putrescine$-incorporation assay. We successfully applied the on-chip assay to a rapid and quantitative analysis of the transglutaminase activity in all-trans retinoic acid-treated NIH 3T3 and SH-SY5Y cells. In addition, the on-chip transglutaminase activity assay was sufficiently sensitive to determine the transglutaminase activity in eleven mammalian cell lines. Thus, this novel on-chip transglutaminase activity assay was confirmed to be a sensitive and high-throughput approach to investigating the roles of transglutaminase in cellular signaling, and, moreover, it is likely to have a strong potential for monitoring human diseases.