• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.562-568
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• 2012

Cytochrome P450 BM3 (CYP102A1) from Bacillus megaterium is a self-sufficient monooxygenase that consists of a heme domain and FAD/FMN-containing reductase domain (BMR). In this report, the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) by BMR was evaluated as a method for monitoring BMR activity. The electron transfer proceeds from NADPH to BMR and then to BMR substrates, MTT and CTC. MTT and CTC are monotetrazolium salts that form formazans upon reduction. The reduction of MTT and CTC followed classical Michaelis-Menten kinetics ($k_{cat}=4120\;min^{-1}$, $K_m=77{\mu}M$ for MTT and $k_{cat}=6580\;min^{-1}$, $K_m=51{\mu}M$ for CTC). Our continuous assay using MTT and CTC allows the simple, rapid measurement of BMR activity. The BMR was able to metabolize mitomycin C and doxorubicin, which are anticancer drug substrates for CPR, producing the same metabolites as those produced by CPR. Moreover, the BMR was able to interact with CYP1A2 and transfer electrons to promote the oxidation reactions of substrates by CYP1A2 and CYP2E1 in humans. The results of this study suggest the possibility of the utilization of BMR as a surrogate for mammalian CPR.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.188-193
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• 2014

Seed viability testing provides valuable information for assessing seed lot germinability. However, most testing methods require destruction of seed prior to test. Because the dissected seeds for viability test cannot be used further evaluation, the nondestructively X-ray photography technique that can be applied for the evaluation of seed quality has been developed. In order to know the validity and accuracy of X-ray photography technique in seed evaluation test that conducted to remove the abnormal seed from a seed lot, we have compared the results from tetrazolium viability test, germination test and X-ray contrast method in cotton. Metallic salts treatment increased the efficiency of X-ray photographic method by enhancing the penetration of X-ray in abnormal or damaged seeds rather than normal seeds that have strong and well-organized tissues in seed. Cotton seeds presoaked for 16 hr in distilled water followed by soaking into metallic salt solution (5% NaI in water) for 60 min were easily classified seeds into dead seed and viable seed based on the radiography images obtained by X-ray radiation. We concluded that soft X-ray photography was reliable to find out the various defective characters due to heat and mechanical damage of seeds.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.3
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• pp.285-291
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• 2022

In order to use the liquid rocket fuel, 1,5-diamino-4-methyltetrazolium azide, [DMT]⁺[N₃]^- and 1,5-diamino-4-methyltetrazolium cyanide, [DMT]⁺[CN]^- were synthesized and prepared the ionic liquid rocket fuel after dissolving the synthesized solid-type energetic chemicals in hydrazine, respectively. The thermal decomposition temperatures(T_d) and densities(d) of the prepared ionic liquid rocket fuels were about 200 ℃ and above 1.0 g/cm³ respectively. The ignition delay times(I_dt) of the ionic liqud rock fuels with [DMT]⁺[N₃]^- and [DMT]⁺[CN]^- were in a range of 26.6 - 82.5 ms and the 44.0 - 98.5 ms, respectively. These results mean that the synthesized tetrazolium salts could be used as an ionic liquid rocket fuels. The viscosities of the ionic liqud rock fuels with [DMT]⁺[N₃]^- and [DMT]⁺[CN]^-, which were dissolved in mixture solution of hydrazine/2-hydroxyethylhydrazine were to be 1.34 - 101 cP, and 1.29 - 80.5 cP, respectively. The synthesized ionic liquid rocket fuels in this study could be used as rocket fuel because the [I_dt(100 ms or less), T_d(150 ℃ or more), d(1.00 g/cm³ or more), and η(40.0~ 100 cP)] were achieved to satisfy the range of the used liquid rocket fuels.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.101-106
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• 2014

In this study, we investigated the proliferative and adhesional effect of human osteoblast like MG-63 cell treated with low intensity pulsed ultrasound (LIPUS). We tested the effectiveness of LIPUS in human osteoblast like MG-63 cells. Cell proliferation was measured using a water soluble tetrazolium salts-1 assay. The mRNA expression of alkaline phosphate, vascular endothelial growth factor (VEGF), integrin alpha 2, colla 1A1 were performed by reverse transcription-polymerase chain reaction. LIPUS was no cytotoxicity in human osteoblast like MG-63 cells. In addition, the data show that treatment with 1 MHz and 3 MHz LIPUS on increased proliferation 7 days after. There were significant increased in mRNA expression of alkaline phosphatase, osteocalcin, VEGF, integrin alpha 2 and colla 1A1 (p<0.05). Therefore, the LIPUS significantly increased differential expression of mRNA levels in osteoblast like MG-63 cell and new possibilities in dental clinical practice.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.163-170
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• 2001

Purpose : The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Materials and Methods : Four human cancer cell lines - PCI-1, SNU-1066, NCI-H630 and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy. For clonogenic assay, cells in $25\;cm^2$ flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for $10\~14$ days. For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. Results : There was minimal variation in the values gained from these two methods with the standard deviation generally less than $5\%$, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the $R^2$ value of $0.975\~0.992$ between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than $30\%$). For cells with low plating efficiency (less than $30\%$), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was after 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. Conclusion : In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least.

• Journal of Nutrition and Health
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• v.53 no.6
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• pp.583-595
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• 2020

Purpose: This study examined the effects of Sargassum horneri extracts on palmitic acid (PA)-induced endoplasmic reticulum (ER) stress in HepG2 cells. Methods: HepG2 cells were treated with varying concentrations of S. horneri extract or PA, and the cell viability was measured by water soluble tetrazolium salts analysis. The effective induction of ER stress and the effects of S. horneri were investigated through an examination of the ER stress-related genes, such as activating transcription factor 4 (ATF4), X-box binding protein (XBP1s), C/EBP homologous protein (CHOP), and 78-kDa glucose-regulated protein (GRP78) by quantitative reverse transcription polymerase chain reaction. The expression and activation levels of unfolded protein response (UPR) associated proteins, such as inositol-requiring enzyme-1α (IRE1α), eukaryotic translation initiation factor 2 alpha submit (eIF2α), and CHOP were examined by western blot analysis. Results: The treatment with PA increased the expression of UPR associated genes significantly and induced ER stress in a 12-hour treatment. Subsequent treatment with S. horneri reduced mRNA expression of ATF4, GRP78, and XBP1s. In addition, the protein levels of phosphate (p)-IRE1α, p-elF2α, and CHOP were also reduced by a treatment with S. horneri. An analysis of sirtuin (SIRT) mRNA expression in the S. horneri and PA-treated HepG2 cells showed that S. horneri increased the levels of SIRT2, SIRT6, and SIRT7, which indicates a possible role in reducing the expression of ER stress-related genes. Conclusion: These data indicate that S. horneri can exert an inhibitory effect on ER stress caused by PA and highlight its potential as an agent for managing various ER stress-related diseases.