• BMB Reports
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• 제38권3호
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• pp.366-369
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• 2005

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450 and also catalyzes the one-electron reduction of many drugs and foreign compounds. Various spectrophotometric assays have been performed to examine electron-accepting properties of CPR and its ability to reduce cytochrome $b_5$, cytochrome c, and ferricyanide. In this report, reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by CPR has been assessed as a method for monitoring CPR activity. The principle advantage of this substance is that the reduction of MTT can be assayed directly in the reaction medium by a continuous spectrophotometric method. The electrons released from NADPH by CPR were transferred to MTT. MTT reduction activity was then assessed spectrophotometrically by measuring the increase of $A_{610}$. MTT reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;20\;{\mu}M$, $k_{cat}\;=\;1,910\;min^{-1}$). This method offers the advantages of a commercially available substrate and short analysis time by a simple measurement of enzymatic activity of CPR.

• Asian-Australasian Journal of Animal Sciences
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• 제21권4호
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• pp.494-498
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• 2008

MTT (3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) reduction assay is a method that validates the viability of an active cell. Dehydrogenase in mitochondria converts yellow colored insoluble tetrazolium salt to purple colored water-soluble formazan. Sperm also have mitochondria in the midpiece, therefore sperm viability could be evaluated by MTT reduction assay. Several studies have already demonstrated the capability of application of the MTT reduction assay to sperm of several species in Hepes-BSA buffer. Because most liquid semen was diluted in extender like BTS (Beltsville Thawing Solution), Modena or Androhep when it is used or transferred, semen needed another dilution in Hepes-BSA buffer to assess sperm viability. In this study, we evaluated boar sperm viability especially in BTS extended semen and compared the efficiency of this test with eosin-nigrosin staining. We used the fresh BTS extended semen from a local A.I center. Semen sample was diluted to $3.0{\times}10^7$ sperms/ml in BTS. The rates of formazan production were measured in 96-well microtiter plates immediately and 1h after incubation at $17^{\circ}C$ using a spectrophotometer at wave length 560 nm. Simultaneously, split samples of the same semen were tested, using eosin-nigrosin staining to compare the efficiency of the MTT assay of sperm viability in BTS. The correlation between the results of these tests was calculated using Student-t test and ANOVA. The results revealed a strong correlation between the results of MTT reduction rate and the results that were simultaneously determined by eosin-nigrosin staining at 1 h. In conclusion, the MTT reduction test was an effective and simple method to validate sperm viability and it could be used as a simple tool to evaluate sperm viability in the local A.I center and laboratory.

• 약학회지
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• 제43권6호
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• pp.851-860
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• 1999

The effects of antimycin A(AA), dodium azide ($NaN_3$) and 2,4-dinitrophenol (DNP), which inhibit mitochondrial ATP production, on cellular functions of cultured astrocytes were studied. High concentrations of AA $(50{\;}\mu\textrm{g}/ml),{\;}NaN_3$ (100mM) and DNP (20mM) significantly decreased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction, which was known to be related to mitochondrial function and then cel viability. AA ($50{\;}\mu\textrm{g}/ml$) increased lactate dehydrogenase (LDH) release and decreased [$^3H$] glutamate uptake, suggesting severe damage of cellular function by the concentrations of the compounds. Meanwhile, low concentrations of AA $(\leq{;\}10{\;}\mu\textrm{g}/ml),{\;}NaN_3{;\}(\leq{\;}50mM)$ and DNP ($\leq{\;}5mM$) significantly increased MTT reduction, the effect of which was specific to astrocytes. AA (5 and $10{\;}\mu\textrm{g}/ml$) did not affect LDH release and [$^3H$] glutamate uptake, indicating that these compounds increased MTT reduction at the low concentrations without cellular membrane damage. However, the low concentrations of AA produced significant decrease of MTT reduction in a glucose-free medium. Low concentrations of AA (1 and $5{\;}\mu\textrm{g}/ml$) did not change ATP production of astrocytes in the medium containing 10 mM glucose, but completely inhibited in a glucose-free medium, suggesting marked increase of cytosolic ATP production by the blockade of mitochondrial ATP production with low concentrations of AA. These results suggest that astrocytes have ability to enhance neuronal function or survival under conditions of incomplete ischemia or early by enhancement of glycolysis, and that cellular reduction of MTT occurs not only mitochondrially but also extramitchondrially.

• 한국수정란이식학회지
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• 제25권4호
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• pp.229-235
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• 2010

The MTT assay is one of superior evaluation methods widely used to analyze the viability of metabolically active cell. It can be used to determine the percentage of viable sperm through measurement of the reduction of MTT granules at mitochondria in sperm tail. The purpose of this study is to determine the optimal condition of a simple and easy MTT assay to validate boar sperm viability and compare the accuracy of this test with microscopic examination. The MTT reduction rate for sperm viability were analyzed in microtiter plates (96 well) from 1 hr to 5 hr incubation periods at $37^{\circ}C$ using spectrophotometer (microplate reader) at 550 nm wavelength. The remainder of semen sample was simultaneously examined to compare the correlation of accuracy between MTT assay and other sperm parameters. Those sperm parameters were included the motility, survival rates, membrane integrity, mitochondria activity and acrosome integrity. The OD values of MTT assay (MTT reduction rates) did not greatly change at 1 hr to 5 hr incubation periods in different proportion of live and freeze-killed sperms (dead sperm). The MTT reduction rates or survival rates were decreased according to the different concentration of live and dead sperm. The linear regression at 1 hr and 4 hr incubation periods in sperm MTT assay was y=291.55x-72.176 and y= 180.64x-44.569, respectively. There are high correlation between 1 hr and 4 hr incubation periods (p<0.001). The results of MTT assay and other sperm parameters has a positive correlation (p<0.01 or 0.05). The correlation coefficients for MTT assay was 0.88115 for motility, 0.89868 for survival rates, 0.91722 for membrane integrity and 0.77372 for acrosome integrity, respectively. In conclusion, the MTT assay can be used as a reliable and efficient evaluation method for boar sperm viability. It can be use practical means to evaluate the quality of boar sperm by a fast, inexpensive and easy method.

• Biomolecules & Therapeutics
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• 제20권6호
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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.

• 한국안광학회지
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• 제1권1호
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• pp.115-118
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• 1996

생쥐 섬유모세포주 L929 세포에 미치는 중금속류와 중금속 착화제의 세포독성 정도를 측정하기 위해 96 well microtiter plate를 이용한 간편한 비색검정 방법, 즉 neutral red(NR)와 tetrazolium MTT 정량을 실시하였다. NR과 MTT정량으로 측정한 결과 세포독성은 카드뮴 > 아연 > 니켈 > 3가크롬의 순서로 나타났다. 또한 두개의 중금속을 동시에 처리한 결과 아연에 의해 카드뮴의 독성이 감소되었으며 니켈과 크롬을 동시에 처리한 결과 니켈의 독성이 감소하였다. 그리고 착화제로 EDTA와 Chitosan을 처리한 결과 세포독성이 현저하게 감소되는 것으로 나타났다.

• Applied Biological Chemistry
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• 제51권1호
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• pp.79-83
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• 2008

본 연구에서는 신경독소일 뿐만 아니라 흥분성 신경전달물질로 잘 알려져 있는 glutamate 세포독성이 산화적 손상과 관련하고 있고, 여기에 방어효과를 보이는 제비꽃 추출물에 관하여 연구하였다. MTT reduction assay를 통하여 glutamate의 세포독성을 확인하였고 ascorbic acid와 같은 대표적인 항산화제를 처리한 후 광학 현미경을 이용한 형태학적 변화를 관찰하였다. N18-RE-105 세포주에 최종 농도 20mM의 glutamate를 처리 하면 40.8% 의 생존율을 보이는데 반하여 ascorbic acid 500 ${\mu}M$ 최종농도로 처리하였을 때 85.3%의 세포 생존율을 확인할 수 있었다. 그리고 신경세포 보호효과를 가지는 제비꽃을 methanol, ethanol, acetone 추출한 뒤 MTT reduction assay를 이용하여 활성을 확인하였으며 그 중 acetone 추출물을 최종농도 50, 100 ${\mu}g/ml$를 처리 시 76.8%, 79.4%로 가장 높은 세포 생존율을 확인할 수 있었다. 이 결과는 N18-RE-105 세포주의 형태학적 변화와 LDH release assey에서도 일치하는 결과를 확인하였다.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.335-337
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• 1997

In this study, we show a convenient MTT assay for detect the susceptibility of yeast-like form of Trichosporon beigelii against antifungal agents. This assay was developed based on mitocondrial respiration by determining reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan. Cells of T beigelii are seeded into 96-well microtiter plates, and antifungal agents, amphotericin B, magainin and CA-ME hybrid peptide were added with various concentrations. After 24 hr incubation, MTT was added, then incubations were continued for 4 hr. Formazan formation was quantified photometrically after extraction of the formazan with acid sodium dodesyl sulfate (SDS). From this assay, we could obtained MICs of antifungal agents against T. beigelii. The presented method can easily be used as an effective methods to assess the antiftingal action of various agents on yeasts with minimal amounts of antifungal agents.

• Journal of Ginseng Research
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• 제21권3호
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• pp.160-168
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• 1997

The present study was carried out to investigate the effects of Panax ginseng saponin extracts on the dexamethasone-induced apoptosis of mouse thymus in vivo and mouse thymocytes in vitro. The saponin fractions of red ginseng (R-SAP) and white ginseng (Wl-SAP) were provided by the Korea Ginseng & Tobacco Research Institute, and the other saponin fraction of white ginseng (W2-SAP) was extracted in our laboratory. 1. The male ICR mice (3~4 wk old; weighing 15$\pm$2 g) were given by each saponin fraction of 5 mg/kg/ day for 4 days, and at one hour after the last treatment, they were injected by deuamethasone (5 mg/kg : DX). The mouse thymus was extracted at 6 hours after DX injection, and they were stained with hematoxylin-eosin reagents and an Apop-Tag kit, respectively, and the thymocytes prepared from it were labelled with anti-mouse FITC-anti-CD4 and anti-mouse PE-anti-CD8 and then analyzed by fluorescence activated cell sorter (FACS). DX-induced reduction of thymus weight was significantly attenuated by W2- SAP but was not affected by other saponin fractions. And DX-induced apoptotic death of thymocytes, appeared in the histologic findings of the thymus, was inhibited by the saponin fractions and the order of these inhibitory potencies was R-SAP》W2-SAP>Wl-SAP. However, in respect of T cell receptors, the differentiation of thymocytes seems not to be changed by treatments with DX or/and the saponin fractions. 2. In the primary thymocyte culture, the DX-induced reduction of thymocyte MTT values was rather greater in RPMI 1640 medium of IWc fetal bovine serum (FBS) or horse serum (HS). In addition, the DX-Induced MTT reduction was significantly inhibited by R-SAP or W2-SAP, in the culture using that medium of 5% FBS or HS. But these saponin fraction did not effected the DX-induced reduction of thymocyte MTT value in primary culture of 10% FBS or 10% HS. These results suggest that R-SAP and some W-SAP fractions may protect thymocyte from stress or glucocorticoisteroid-induced death of them.

• Biomolecules & Therapeutics
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• 제3권3호
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• pp.242-244
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• 1995

In vitro cell culture system has been proposed as a promising alternative model to in vivo skin irritation test. These studies were performed to screen the cytotoxicity effects of surfactants using normal human skin fibroblasts. Cell membrane integrity assessed by the leakage of lactate dehydrogenase (LDH) and mitochondrial integrity by MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromides reduction test were affected in a dose dependent manner. The irritation potential of surfactants to human skin patch test, and the changes of capillary permeability by rabbit intradermal safety test were assessed as in vivo methods. Our results suggest that LDH leakage assay and MTT reduction test using cultured human fibroblasts could be predictive for the irritancy of various surfactants in human, and LDH assay is superior correlated with in vivo test (r=0.886) to MTT test with in vivotest (r=0.757).