• Journal of Microbiology and Biotechnology
• /
• v.30 no.11
• /
• pp.1750-1759
• /
• 2020

The characterization of cytochrome P450 CYP125A13 from Streptomyces peucetius was conducted using cholesterol as the sole substrate. The in vitro enzymatic assay utilizing putidaredoxin and putidaredoxin reductase from Pseudomonas putida revealed that CYP125A13 bound cholesterol and hydroxylated it. The calculated K_D value, catalytic conversion rates, and Km value were 56.92 ± 11.28 μM, 1.95 nmol min^-1 nmol^-1, and 11.3 ± 2.8 μM, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that carbon 27 of the cholesterol side-chain was hydroxylated, characterizing CYP125A13 as steroid C27-hydroxylase. The homology modeling and docking results also revealed the binding of cholesterol to the active site, facilitated by the hydrophobic amino acids and position of the C27-methyl group near heme. This orientation was favorable for the hydroxylation of the C27-methyl group, supporting the in vitro analysis. This was the first reported case of the hydroxylation of cholesterol at the C-27 position by Streptomyces P450. This study also established the catalytic function of CYP125A13 and provides a solid basis for further studies related to the catabolic potential of Streptomyces species.

• Genomics & Informatics
• /
• v.12 no.4
• /
• pp.231-235
• /
• 2014

Elevated serum uric acid levels are associated with a variety of adverse health outcomes, including gout, hypertension, diabetes mellitus, metabolic syndrome, and cardiovascular diseases. Several genome-wide association studies on uric acid levels have implicated the ATP-binding cassette, subfamily G, member 2 (ABCG2) gene as being possibly causal. We investigated an association between the single-nucleotide polymorphism (SNP) rs2725220 in the ABCG2 gene and uric acid levels in the Korean population. A total of 991 subjects in Seoul City were used for a replication study with ABCG2 SNP rs2725220. The rs2725220 SNP in the ABCG2 gene was associated with mean uric acid levels (effect per allele 0.25 mg/dL, p < 0.0001). Subjects with the GC/CC genotype had a 1.78-fold (range, 1.22- to 2.62-fold) higher risk of having abnormal uric acid levels (${\geq}7.0mg/dL$) than subjects with the GG genotype. When analyzed by gender, the association with ABCG2 was stronger in men than in women. The association with ABCG2 was much stronger in male subjects with body mass index (BMI) ${\geq}26.4$ (odds ratio, 5.09; 95% confidence interval, 2.41 to 10.8) than in male subjects with BMI < 26.4. This study clearly demonstrates that genetic variations in ABCG2 influence uric acid levels in Korean adults.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.12
• /
• pp.3049-3052
• /
• 2009

Methyl tert-butyl ether (MTBE) is added to gasoline to enhance the octane number of gasoline, tert-butyl alcohol (TBA) is major degradation intermediate of MTBE in environment, and benzene, toluene, ethyl benzene and xylene (BTEX) are also major constituents of gasoline. In this study, a simplified headspace analysis method was adapted for simultaneous determination of MTBE, TBA and BTEX in ground water samples. The sample 5.0 mL and 2 g NaCl were placed in a 10 mL vial and the solution was spiked with fluorobenzene as an internal standard and sealed with a cap. The vial was placed in a heating block at 85 $^{\circ}C$ for 30 min. The detection limits of the assay were 0.01 ${\mu}$g/L for MTBE and BTEX, and 0.02 ${\mu}$g/L for TBA. The method was used to analyze 110 ground water samples from various regions in Korea, and to survey the their background concentration in ground water in Korea. The samples revealed MTBE concentrations in the range of 0.01 - 0.45 ${\mu}$g/L (detection frequency of 57.3%), TBA concentrations in the range of 0.02 - 0.08 ${\mu}$g/L (detection frequency of 5.5%), and total BTEX concentrations in the range of 0.01 - 2.09 ${\mu}$g/L (detection frequency of 87.3%). The developed method may be used when simultaneously determining the amount of MTBE, TBA and BTEX in water.

• The Korean Journal of Community Living Science
• /
• v.22 no.4
• /
• pp.615-621
• /
• 2011

This study was conducted to evaluate of the protection efficiency in each part of developed pesticide-proof clothes by repeated washings. We investigated the effect of repeated laundering on mechanical properties of pesticide-proof clothes (not washed vs 5 times washed). We also examined pesticide infiltration rate into the pesticide-proof clothes by repeated laundering. The patches(TCL paper, surface area 50cm2)were attached to the inside of pesticide-proof clothes(head, chest, right upper-arm, right forearm, left thigh, left calf, back) which subjects had dressed in during pesticide spraying. The patches were detached from working clothes after work. For the extraction of pesticide in pesticide-proof clothes, sonication was applied for 30 min with methanol. The gas chromatography/mass spectrometry (GC/MS) was applied to identify the pesticide component. The results of this study are as follows: The force strength, water-vapour resistance and surface wetting resistance of pesticide-proof clothes decreased 5 times more in washed clothes. The concentration of pesticide was the highest in the head area of pesticide-proof clothes. In seven parts of TLC paper attached to the pesticide proof clothes, the concentration of pesticide was higher in the left thigh. The penetration part and concentration of pesticide increased as washing was repeated. Therefore the conclusion which can be drawn from this study is this: protection efficiency of pesticide-proof clothes decrease by repeated washings.

• Publications of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.255-259
• /
• 2015

Recent narrow-band Ca photometry discovered two distinct red giant branch (RGB) populations in some massive globular clusters (GCs) including M22, NGC 1851, and NGC 288. In order to investigate the differences in light/heavy elements abundances between the two subpopulations, we have performed low-resolution spectroscopy for stars on the two RGBs in these GCs. We find a significant difference (more than $4{\sigma}$) in calcium abundance from the spectroscopic HK' index for both M22 and NGC 1851. We also find a more than $8{\sigma}$ difference in CN band strength between the Ca-strong and Ca-weak subpopulations. For NGC 288, however, we detect the presence of a large difference only in the CN strength. The calcium abundances of the two subpopulations in this GC are identical within errors. We also find interesting differences in CN-CH relations among these GCs. While CN and CH indices are correlated in M22, they show an anti-correlation in NGC 288. However, NGC 1851 shows no difference in CH between two groups of stars having different CN strengths. The CN bimodality in these GCs could be explained by pollution from intermediate-mass asymptotic giant branch stars and/or fast-rotating massive stars. For the presence or absence of calcium bimodality and the differences in CN-CH relations, we suggest these would be best explained by how strongly type II supernovae enrichment has contributed to the chemical evolutions of these GCs.

• Korean Journal of Food Science and Technology
• /
• v.46 no.4
• /
• pp.418-424
• /
• 2014

High-acidity vinegar was manufactured using pear concentrate by fed-batch fermentation without additional nutrients, and the physicochemical properties and volatile components were investigated at different fermentation stages (Stages 1-4) and at various initial alcohol concentrations (IAC; 6-9%). The levels of reducing sugar, free amino acids, total phenolic content, total flavonoid content, and radical scavenging ability increased slightly during Stage 4 (high-acidity vinegar), which was affected by alcohol feeding. The contents of approximately 20 types of volatile compounds differed between the moderate- and high-acidity vinegar samples, as determined by solid-phase microextraction/gas chromatography-mass spectroscopy. The level of acetic acid in high-acidity vinegar increased according to the initial alcoholic content applied. The high-acidity vinegar produced by fed-batch culture at an IAC of 6-7% showed improved physicochemical and volatile properties as compared to the moderate-acidity vinegar.

• Journal of Applied Biological Chemistry
• /
• v.55 no.2
• /
• pp.103-107
• /
• 2012

Acanthopanax sessiliflorus Seeman fruits (Araliaceae) were extracted at room temperature with 70% aqueous ethanol (EtOH). The concentrated extract was partitioned with ethyl acetate (EtOAc), n-butyl alcohol, and $H_2O$, successively. From the EtOAc fraction, four compounds were isolated through the repeated silica gel and octadecyl silica gel (ODS) column chromatographies. According to the results of physico-chemical and spectroscopic data including NMR, IR, and gas chromatography/mass spectrometer, the chemical structures of the compounds were determined as stigmasterol (1), linoleic acid (2), ${\beta}$-sitosterol (3), and stigmast-5-en-$3{\beta}$,$7{\beta}$-diol (4).

• Polymer(Korea)
• /
• v.33 no.1
• /
• pp.1-6
• /
• 2009

We report the template-based synthesis of well-dispersed CdS nanoparticles (NPs) in the interior of poly (2-acetamidoacrylic acid) (PAAA) hydrogel as a novel type of nanocomposite without particle aggregation via ion exchange in a aqueous system. As revealed by the TEM image analysis, the mean crystallite diameter of CdS NPs embedded in hydrogel composite was 4.5 nm, and the composite did not suffer any observable change after 6 months. Desorption/decomposition of CdS/PAAA hydrogel composite was studied by evolved gas analysis-gas chromatography-mass spectrometry (EGA-GC-MS), and thermogravimetric analysis (TGA) methods. From the TGA data, the thermal stability of the composite system increased by ca. 100 $^\circ$C and the content of CdS NPs in a dry composite gel was over 70 wt%. In addition, the chemical pathway was proposed for the entire decomposition process.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.27 no.1
• /
• pp.23-37
• /
• 2017

Objectives : This study was conducted to evaluate the level of exposure to volatile organic compounds (VOCs) among workers handling rust preventive oils. Methods : A total of 30 bulk samples and 54 personal air samples were collected using diffusive samplers at 22 workplaces handling rust preventive oils in Daegu and Gyongsangbuk-do Province from March to October 2013. We also investigated detailed information on the related work conditions, such as kinds of products, handling methods, local exhaustive ventilation systems, and the status of the wearing personal protective equipment. All bulk samples and air samples were analyzed using gas chromatography mass spectrometry (GC-MS) to identify components to which workers potentially were exposed. Quantitative airborne concentrations of VOCs were confirmed using gas chromatography with flame ionized detectors. Results : In terms of qualitative analyses for the 30 bulk samples, we found carcinogenic, mutagenic and reproductive toxic(CMR) substances such as butane(carcinogenic Group 1A, mutagenic Group 1B), butoxy ethanol(carcinogenic Group 2), cumene (carcinogenic Group 2), ethyl benzene(carcinogenic Group 2), methyl isobutyl ketone(carcinogenic Group 2) and toluene (reproductive toxic, Group 2). As a result of full-shift based personal air samples, eight substances such as n-hexane, n-heptane, octane, nonane, decane, toluene, ethyl benzene and xylene were detected. Among them, n-hexane and n-heptane were detected in all of 54 air samples with $13.13mg/m^3$ and $8.61mg/m^3$ of maximum concentration, respectively. The level of airborne concentration from all of samples were bellow the occupational exposure limit in Korea. Conclusions : Based on the results of this study, workers handling rust preventive oils could be exposed to CMR substances contained in rust preventive oils and n-hexane and n-heptane were found as the most frequent sources of VOC exposure.

• Journal of Plant Biotechnology
• /
• v.47 no.1
• /
• pp.100-106
• /
• 2020

Coix lacryma-jobi (Hanjeli) is known to posses anti-microbial properties. Therefore, phytochemical compounds of C. lacryma-jobi have been studied to produce novel antimicrobial agents as treatments against antibiotic-resistant bacteria.The objective of this study was to determine the phytochemical composition and antibacterial activity of the C. lacryma-jobi oil against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The phytochemical composition of the oil was determined via gas chromatography mass spectrophotometry (GC-MS). Moreover, agar disk and agar well diffusion were employed to screen the antibacterial activity of the oil. An agar well diffusion test was implemented to determinate MIC's (minimum inhibitory concentrations). Dodecanoic acid, tetradecanoic acid, 2,3-dihydroxypropylester, 1,3-dioctanoin, N-methoxy-N-methyl-3,4-dihydro-2H-thiopyran6-carboxamide, propanamide, 5-Amino-1-(quinolin-8-yl)-1,2,3-triazole-4-carboxamide, and pyridine were identified in the C. lacryma-jobi oil. The MIC value of the oil was 0.031 g/L and the MBC of the oil was 0.125 g/L effective in all test bacteria. Dodecanoic acid displayed inhibitory activity against gram-positive and gram-negative bacteria. Therefore, our research demonstrated C. lacryma-jobi (Hanjeli) oil exhibited antibacterial activity against E. coli, S. aureus, and B. subtilis. These research suggest that C. lacryma-jobi root oil could be used for medicinal purposes; however clinical and in vivo tests must be performed to evaluate its potential as an antibacterial agent.