• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.135-144
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• 2005

In the high-Ca limestone zone of the Pungchon Formation of the Lower Chosun Supergroup, cryptocrystalline alterations with reddish brown color occur as fissure-fillings or coatings, which was originated from the upper formation, i. e., the Hwajeol Formation. The precipitates result in degradation and contamination of the high-Ca limestone ore in grade and quality, showing characteristic occurrence and mineral composition typical of suggesting a supergene origin. Chalcedonic quartz, kaolinite, illite, goethite and hematite are constituting a characteristic authigenic mineral assemblage and, in places, smectite is less commonly included in the weathering product. In addition to these authigenic phases, some detrital minerals such as mica and orthoclase constituting relatively coarser grains are also rarely present in the supergene alterations. A rather complex clay facies consisting of kaolinite, illite and smectite in the alterations seems to correspond to the typical clay composition of the reported residual pedogenic soils by limestone weathering. The cryptocrystalline weathering product is partly altered to stilbite, a characteristic hydrothermal zeolite, in places, by the hydrothermal contact of late stage. The time of formation and infiltration of the supergene alterations seems to correspond to the stage just after the epithermal alteration of the Pungchon Limestone, i. e., an early Jurassic age. The supergene alteration, which may imply the stage of uplifting, weathering and erosion of the Chosun Supergroup, appears to have undergone at an oxygen-rich environment in descending water of meteoric origin by means of a chemical leaching and diffusion.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.216-222
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• 2003

Human caspase-9, an essential apoptosis initiator protease, was excessively degraded when expressed in Escherichia coli under the conventional induction condition. To optimize the conditions for induction and develop a rapid purification method for obtaining significant amounts of wild-type procaspase-9, we expressed procaspase-9 as GST fusion in E. coli. The addition of 0.01 mM IPTG as an inducer to the bacterial culture and decreasing the culture temperature to 25oC improved the production of procasapse-9 protein by circumventing proteolytic degradation in E. coli. The wild-type procaspae-9 was purified to approximately 70% purity with relatively high yields using the method developed in this study. In addition, we found that GST-caspase-9 is autocatalytically cleaved after aspartic acid 315, which is the same site for processing in mammalian cells, during expression in E. coli.

• Korean Journal of Microbiology
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• v.35 no.2
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• pp.139-145
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• 1999

Aromatic hydrocarbons which are not easily degraded by microorganisms can be accumulated in the conlaminated environment for a long lime, producing toxic effects on wild lives and humans. However, the sublethal concentrations of the chemicals induce the synthesis of stress-shock proteins in the cells and increase the adaptability of the organisms to the environmental stresses. In this study, therefore, the cells of Psezido~nonus sp. DJ- 12 treated with catechol at various concentrations were inveshgated for their survival, biodegtadability of catechol, production of stress-shock proteins, and cytological changes. The organisms were capable of degrading catechol at the range of 0.5 to 1.0 mM concentration wilhin 6 hours incubation, but they were killed by $10^2$-10$^3$ celllinl at 3 mM or higel- concentration without any catechol degradation. These cells treated with catechol begm lo produce DnaK and GroEL at 1 mM and 0.5 mM. respectively. Pseudumonas sp. DJ-12 treated with 10 mM catechol for I hour exhihiled some punctuated pores on the cell wall and contortion of the rod shape. The cells treated with he sublethal concentration of catechol showed the increased tolerance for suvival when exposed to the lethal concentration, and such tolerant effects were functioned crossly among benzoate, 4-chlorobenzoate, 'and catechol.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.352-364
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• 2016

In this study, we examined in vitro the potential probiotic properties of lactic acid bacteria (LAB) obtained from the fish intestine and their ability to degrade histamine through the production of diamine oxidase (DAO) enzymes and bacteriocin. Among 97 LAB strains isolated from the intestine of croaker, flatfish, pollack, and rockfish, CIL08, CIL16, FIL20, FIL31, PIL45, PIL49, PIL52, and RIL60 isolates exhibited excellent survival rates under simulated gastrointestinal tract conditions, high adhesion ability to HT-29 epithelial cells, and resistance to the antibiotics such as amoxicillin, ampicillin, erythromycin, penicillin G, streptomycin, tetracycline, or vancomycin. In addition, these strains did not produce histamine in decarboxylating broth containing histidine. In particular, 4 strains (CIL08, FIL20, PIL52, and RIL60) that may produce DAO were significantly able to degrade histamine. The bacteriocins produced by FIL20, FIL31, and PIL52 LAB inhibited the growth and histamine production of Enterococcus aerogenes CIH05, Serratia marcescens CIH09, Enterococcus faecalis FIH11, Pediococcus halophilus FIH15, Lactobacillus sakei PIH16, Enterococcus faecium PIH19, Leuconostoc mesenteroides RIH25, or Aeromonas hydrophilia RIH28. Histamine-producing strains isolated from fish intestine were found to reduce histamine accumulation during co-culture with CIL08, FIL20, PIL52, and RIL60 LAB showing histamine degradation or bacteriocin production ability. The probiotic strains preventing histamine formation were identified as Pediococcus pentosaceus CIL08, Lactobacillus plantarum FIL20, Lactobacillus paracasei FIL31, Lactobacillus sakei PIL52, and Leuconostoc mesenteroides RIL60 with high similarity based on 16S rRNA gene sequencing.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.243-248
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• 2016

RNase E (Rne) is an essential enzyme involved in the processing and degradation of a large portion of RNAs in Escherichia coli. The enzymatic activity of RNase E is controlled by regulators of ribonuclease activity, namely, RraA and RraB. Gram-positive bacterium Streptomyces coelicolor also contains homologs of Rne and RraA, designated as RNase ES (Rns), RraAS1, and RraAS2. In the present study, we investigated the effect of S. coelicolor RraAS1 on the ribonucleolytic activity of RNase E in E. coli. Coexpression of RraAS1 with Rne resulted in the decreased levels of rpsO, ftsZ, and rnhB mRNAs, which are RNase E substrates, and augmented the toxic effect of Rne overexpression on cell growth. These in vivo effects appeared to be induced by the binding of RraAS1 to Rne, as indicated by the results of co-immunoprecipitation analysis. These results suggested that RraAS1 induces ribonucleolytic activity of RNase E in E. coli.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.219-226
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• 2015

The anticancer activity of a methanolic extract from lemon leaves (MLL) was assessed in MCF-7-SC human breast cancer stem cells. MLL induced apoptosis in MCF-7-SC, as evidenced by increased apoptotic body formation, sub-G1 cell population, annexin V-positive cells, Bax/Bcl-2 ratio, as well as proteolytic activation of caspase-9 and caspase-3, and degradation of poly (ADP-ribose) polymerase (PARP) protein. Concomitantly, MLL induced the formation of acidic vesicular organelles, increased LC3-II accumulation, and reduced the activation of Akt, mTOR, and p70S6K, suggesting that MLL initiates an autophagic progression in MCF-7-SC via the Akt/mTOR pathway. Epithelial-mesenchymal transition (EMT), a critical step in the acquisition of the metastatic state, is an attractive target for therapeutic interventions directed against tumor metastasis. At low concentrations, MLL induced anti-metastatic effects on MCF-7-SC by inhibiting the EMT process. Exposure to MLL also led to an increase in the epithelial marker E-cadherin, but decreased protein levels of the mesenchymal markers Snail and Slug. Collectively, this study provides evidence that lemon leaves possess cytotoxicity and anti-metastatic properties. Therefore, MLL may prove to be beneficial as a medicinal plant for alternative novel anticancer drugs and nutraceutical products.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.407-415
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• 2019

The biological half-life of pesticides applied on crops is the key indicator for ensuring the safety of agricultural products. The biological half-life is affected by the several factors like growing conditions of the crop, climate, application method, and physicochemical properties of pesticides. In this study, the biological half-life was calculated and the degradation rates of six triazole fungicides sprayed on perilla leaves were evaluated. Moreover, the statistical analysis confirmed the correlation between the biological half-life and physicochemical properties of six triazole pesticides. The recoveries of the six pesticides were between 84.8-104.9%, which satisfied the residual pesticide analysis criteria. The biological half-life of six pesticides sprayed on perilla leaves, calculated using the first-order kinetics model, ranged between 6.4-15.1 days. When the biological half-life and the physicochemical properties were correlated using the principal component analysis: pKa and Log P, the biological half-life was found to be affected by PC1. The correlation coefficient between biological half-life and physicochemical properties (pKa), calculated by Spearman rank-order correlation, was R² = -0.928 (p <0.01). Biological half-life has been shown to correlate with pKa. In conclusion, it can be used as a database for the relationship between biological half-life and physicochemical properties and will contribute to ensure safe supply of agricultural products.

• Analytical Science and Technology
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• v.13 no.5
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• pp.659-665
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• 2000

The changes in $UV_{254}$ and concentrations of $H_2O_2$ formed by ozonation of aqueous humic acid in ozone/high pH, peroxone process and in the presence of radical scavenger, $HCO_3{^-}$ were investigated. This study confirmed that the formation of $H_2O_2$ by ozonation may undergo different reaction pathways compared to those of $UV_{254}$ reduction in the degradation of the humic acid. The concentration of $H_2O_2$ produced by ozonation was found to be increased with decreasing pH of the sample solution due to the higher stability of ozone molecules at acidic conditions. On the while, $UV_{254}$ reduction was found to be higher at alkaline conditions or larger amount of $H_2O_2$ additions as a radical promoter in which the producing of ${\cdot}OH$, ${\cdot}HO_2$ radicals can be more favorable. From the results, it has been suggested that the formation of $H_2O_2$ by ozonation depends mainly on the direct reactions of ozone with humic acid molecules, while $UV_{254}$ reduction is affected by both the indirect reactions of the radicals and direct reactions of ozone with humic acid.

• Journal of Pharmaceutical Investigation
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• v.36 no.4
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• pp.271-276
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• 2006

Felodipine, a calcium-antagonist of dihydropyridine type, is a poorly water soluble drug and has very low bioavailability. As preceding studies, use of solid dispersion systems and surfactants(solubilizers) has been suggested to increase dissolution and to improve bioavailability of felodipine. But in case of solid dispersion systems, large amount of toxic organic solvents should be used and manufacturing process time become longer than conventional process. In case of using surfactants, as time elapsed, decreasing of dissolution rate of felodipine due to crystallization has been reported. In this study, Copovidon as a hydrophilic polymer and $Transcutol^{\circledR}$ as a surfactant were combined to formulations if order to increase dissolution of felodipine and conventional wet granulation process were applied to manufacturing of formulations. The effect of Copovidon and $Transcutol^{\circledR}$ on the dissolution oi felodipine was investigated in-vitro. When Copovidon and $Transcutol^{\circledR}$ used simultaneously, the dissolution rate of felodipine was prominently increased compared with when used separately and the maximum increase in the dissolution of felodipine was 5.8 fold compared to control. This is most probably due to synergy effect by combination of Copovidon and $Transcutol^{\circledR}$. Felodipine sustained release tablets were successfully formulated using several grades of HPMC as a release retarding agent. The stability of felodipine sustained release tablet was evaluated after storage at accelerated condition($40^{\circ}C/75%\;RH$) for 6months in HDPE(High density polyethylene) bottle. Neither significant degradation nor change of dissolution rate for felodipine was observed after 6months. In conclusion, felodipine sustained release tablet was successfully formulated and dissolution of felodipine, poorly water soluble drug, was prominently increased and also stability was guaranteed by using combination system of hydrophilic polymer and surfactant.

• Journal of Conservation Science
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• v.32 no.1
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• pp.21-32
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• 2016

Animal glue is a traditional material used extensively as adhesive and binder in mother-of-pearl, wooden structure, traditional painting, etc. Analysis of animal glue is usually performed with IR(infrared spectroscopy) based on the IR absorption of functional group. But, it has a limitation in confirming animal glue when a sample consists of several materials because of overlapping of the absorption band. Py/GC/MS(pyrolysis/gas chromatography/mass spectrometry) is a useful tool in analyzing the constituent of polymeric materials like animal glue by identifying their pyrolysate with very small amount of sample. In this study, confirmation of animal glue in a Dancheong sample was tried with this method. Characteristic pyrolytic compounds of animal glue and tung oil used in Dancheong were identified. Dancheong sample painted with Noerok as a coloring material, animal glue and tung oil was prepared and it was possible to find characteristic peaks of animal glue after thermal degradation and artificial weathering experiment. From this, we found that animal glue can be detected using py/GC/MS in cultural heritage samples consisting of several materials and in different condition. IR was also tried to analyze Dancheong sample and the results were compared with those of py/GC/MS for the detection of animal glue.