• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.731-732
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• 2003

Mutagen X (MX), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone is one of the most potent directing acting mutagen ever tested in SAL TA100 assay. Although MX analogues have been synthesized, tested for mutagenicity and modeled by structure-activity relationship (SAR) methods, the mechanism of interaction of these compounds with DNA to produce their remarkable mutagenic potency remains unresolved. MX exists as an equilibrium mixture of both ring and open form in water. This equilibrium is very fast for Ames test. Because the mixture is not separable by experimental methods, it is not clear which one is really responsible for the observed mutagenicity. There have been many debates that which one is really responsible for the observed mutagenicity. We used ab initio methods for the MX analogues. It seems both ring and open form could react with DNA bases as electrophiles. However, every open form has consistently lower LUMO energy than corresponding ring form. It is reasonable to assume that the major reaction will go through via open form for MX analogues. This suggest that the open form is more likely really mutagenic.

• Toxicological Research
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• 제24권1호
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• pp.29-36
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• 2008

The present study investigated the anti-proliferative and chemosensitizing effects of Crinum asiaticum var. japonicum against multi-drug resistant (MDR) cancer cells. The 80% methanol extract, chloroform ($CHCl_3$) fraction and butanol (BuOH) fraction of C. asiaticum inhibited the growth of mitoxantrone (MX) resistant HL-60 (HL-60/MX2) cells. When HL-60/MX2 cells were treated with the $CHCl_3$ and BuOH fractions, DNA ladder and sub-G1 hypodiploid cells were observed. Furthermore, the fractions reduced BcI-2 mRNA levels, whereas Bax mRNA levels were increased. These results suggest that the inhibitory effect of C. asiaticum on the growth of the HL-60/MX2 cells might arise from the induction of apoptosis. Treatment of HL-60/MX2 cells with the fractions markedly decreased the mRNA levels of the multi-drug resistance protein-1 and breast cancer resistance protein. The $CHCl_3$ fraction and hexane fraction increased MX accumulation in HL-60/MX2 cells. These results imply that the $CHCl_3$ fraction of C. asiaticum plays a pivotal role as a chemosensitizer. We suggest that components of C. asiaticum might have a therapeutic potential for the treatment of MDR leukemia.

• 분석과학
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• 제24권2호
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• pp.94-104
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• 2011

본 연구에서는 양쪽성 메조 다공성 실리카를 다양한 조건(용매, 계면활성제와 올리고머의 량, 용액의 pH)에서 합성하였다. 메조 다공성 실리카를 사용하여 염소 소독으로 인해 음용수 중에 미량 존재하는 변이원성 물질인 MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2-(5H)-furanone)의 흡착에 관한 특성을 연구하였다. 소수성과 친수성의 양쪽성 폴리우레탄 올리고머를 사용하여 합성된 메조다공성 실리카의 경우 뛰어난 흡착특성을 나타내었다. 그리고 보조 계면 활성제의 경우에는 비이온성이며 분자량이 큰 폴리 에틸렌 프로필렌 옥사이드(PEO-PPO)를 사용하여 합성된 메조 다공성 실리키가 가장 좋은 흡착 특성을 보였다.

• 방사성폐기물학회지
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• 제19권1호
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• pp.1-7
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• 2021

The pH dependence of sorption distribution coefficient (Kd) of Np(IV) on MX-80 in Ca-Na-Cl type solution with the ionic strength of 0.3 M, which was similar to one of the reference groundwaters in crystalline rock, was experimentally investigated under the reducing conditions. The overall trend of Kd on MX-80 was independent of pH at 5 ≤ pH ≤ 10 but increased as pH increased at pH ≤ 5. The 2-site protolysis non-electrostatic surface complexation and cation exchange model was applied to the experimentally measured pH dependence of Kd and the optimized surface complexation constants of Np(IV) sorption on MX-80 were estimated. The values of surface complexation constants in this work agreed relatively well with those in the Na-Ca-Cl solution previously evaluated, suggesting that compared to Na+, the competition of Ca2+ with Np(IV) for surface complexation on MX-80 was not much strong in Ca-Na-Cl solution. The sorption model well predicted the pH dependence of Kd values but slightly overestimated the sorption at the low pH region.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.894-900
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• 2021

This paper examines sorption of Pd(II) onto illite, MX-80 bentonite, and Queenston shale in Na-Ca-Cl solutions of varying ionic strength (IS) from 0.01 to 6.0 mol/L (M) and pH_c ranging from 3 to 9 under atmospheric conditions. A 2-site protolysis non-electrostatic surface complexation and cation exchange model was applied to the Pd sorption onto illite and MX-80 using PHREEQC, and the model results were compared to the experimental ones obtained in this work. Surface complexation and cation exchange constants were estimated for both illite and MX-80 through the optimization process to bring the predicted distribution coefficients from the model into alignment with the experimentally derived values. These optimized surface complexation constants were compared to existing linear free energy relationships (LFER).

• Journal of Ginseng Research
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• 제43권2호
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• pp.186-195
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• 2019

Background: Notoginseng stem-leaf (NGL) ginsenosides have not been well used. To improve their utilization, the biotransformation of NGL ginsenosides was studied using ginsenosidase type-I from Aspergillus niger g.848. Methods: NGL ginsenosides were reacted with a crude enzyme in the RAT-5D bioreactor, and the dynamic changes of multi-ginsenosides of NGL were recognized by HPLC. The reaction products were separated using a silica gel column and identified by HPLC and NMR. Results: All the NGL ginsenosides are protopanaxadiol-type ginsenosides; the main ginsenoside contents are 27.1% Rb3, 15.7% C-Mx1, 13.8% Rc, 11.1% Fc, 7.10% Fa, 6.44% C-Mc, 5.08% Rb2, and 4.31% Rb1. In the reaction of NGL ginsenosides with crude enzyme, the main reaction of Rb3 and C-Mx1 occurred through Rb3${\rightarrow}$C-Mx1${\rightarrow}$C-Mx; when reacted for 1 h, Rb3 decreased from 27.1% to 9.82 %, C-Mx1 increased from 15.5% to 32.3%, C-Mx was produced to 6.46%, finally into C-Mx and a small amount of C-K. When reacted for 1.5 h, all the Rb1, Rd, and Gyp17 were completely reacted, and the reaction intermediate F2 was produced to 8.25%, finally into C-K. The main reaction of Rc (13.8%) occurred through Rc${\rightarrow}$C-Mc1${\rightarrow}$C-Mc${\rightarrow}$C-K. The enzyme barely hydrolyzed the terminal xyloside on 3-O- or 20-O-sugar-moiety of the substrate; therefore, 9.43 g C-Mx, 6.85 g C-K, 4.50 g R7, and 4.71 g Fc (hardly separating from the substrate) were obtained from 50 g NGL ginsenosides by the crude enzyme reaction. Conclusion: Four monomer ginsenosides were successfully produced and separated from NGL ginsenosides by the enzyme reaction.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.419-423
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• 2012

A xylanolytic bacterial strain, MX47, was isolated from rotting plant matter in soil. The strain was aerobic and gram positive, and grew between pH 6.0 and 11.0. Cells were susceptible to thiostrepton and chloramphenicol. The major fatty acids (>3%) comprised 64.55% of iso-$C_{15:0}$, 22.76% of anteiso-$C_{15:0}$, and 3.92% of iso-$C_{17:0}$. The G/C content of the DNA was 44.15 mol%. The predominant respiratory quinone was menaquinone 7 (MK-7). Searches for 16S rRNA gene sequence similarity as well as phylogenetic analyses strongly suggested that the strain should be classified to the genus Bacillus. However, its biochemical characteristics, including acid production and enzyme activities, are different from those of other Bacillus strains in the same clade, and therefore, we propose the name Bacillus sp. MX47.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.396-399
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• 1996

High-performance liquid chromatographic method with UV detecction was developed for the determination of theophylline and its metabolites in human urine using ${beta}$-hydroxyethyl theophylline$({beta} -HET)$ as an internal standard. For extraction of urine sample, quality control sample and xanthine-free blank urine were mixed with decylamine (ion-paring reagent) and ${beta}$-HET. After saturation with ammonium sulfate, the mixture was then extracted with organic solvent at pH values of 4.0-4.5. All separations were performed with ion-pair chromatography using decylamine as an ion-pairing reagent and 3mM sodium acetate buffered mobile phase (pH 4.0) containing 1% (v/v) acetonitrile and 0.75 mM decylamine. The detection limits of theophylline, 1, 3-DMU, 1-MU, 3-MX and 1-MX in human urine were 0.17, 0.17, 0.39, 0.19 and 0.19 ${\mu}g$/ml, based on a signal-to-noise ratios of 3.0. The mean intraday coefficients of variation (C.V.s) of each compound on nine replicates were lower than 2.0%, while mean interday C.V.s on three days were lower than 1.6%. All separations were finished within 40miutes.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1795-1802
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• 2005

Potential energy curves and internuclear (M-X) distance variations for dissociation reactions of $[MX_4]^{2-}$ into ($[MX_3]^-$ + $X^-$) have been calculated using ab initio Hartree-Fock (HF), second order M$\ddot{o}$ller-Plesset perturbation (MP2), and Density Functional Theory (DFT) methods with a triple zeta plus polarization (TZP) basis set. The equilibrium geometrical structures of $[MX_4]^{2-}$ are optimized to tetrahedral geometry for $[NiX_4]^{2-}$ and square planar geometry for ($[PdX_4]^{2-}$ and $[PtX_4]^{2-}$). The bond (M-X) distances of $[NiCl_4]^{2-}$, $[NiBr_4]^{2-}$, $[PdCl_4]^{2-}$, $[PdBr_4]^{2-}$, $[PtCl_4]^{2-}$, and $[PtBr_4]^{2-}$ at the DFT level are 2.258, 2.332, 2.351, 2.476, 2.367, and 2.493 $\AA$, respectively. The dissociation energies for the bond dissociation of ($[MX_3]^-$${\cdot}{\cdot}{\cdot}$$X^-$) at the DFT level are found to be 4.73 eV for $[NiCl_4]^{2-}$, 4.89 eV for $[NiBr_4]^{2-}$, 4.93 eV for $[PdCl_4]^{2-}$, 5.57 eV for $[PdBr_4]^{2-}$, 5.44 eV for $[PtCl_4]^{2-}$, and 5.87 eV for $[PtBr_4]^{2-}$. As the (M${\cdot}{\cdot}{\cdot}$X) distance of ($[MX_3]^-$${\cdot}{\cdot}{\cdot}$$X^-$) increases, the distance variation (Rt) of trans (M-X) bond at the trans-position is shorter than those (Rc) of two cis (M-X) bonds at the cisposition. Simultaneously the atomic charge variation of trans-X atom is more positive than those of equilibrium $[MX_4]^{2-}$ structures, while the variation of leaving X group is more positive.

• 대한미생물학회지
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• 제21권3호
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• pp.375-380
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• 1986

Thirty-one strains of Pseudomonas aeruginosa were submitted to the synergistic activity test of amikacin(AK) and gentamicin(GM) combined with moxalactam(MX), ceftizoxime(CTZ) or cefoperazone(CFZ). The minimal inhibitory concentrations(MICs) of each drug and drugs combined in various ratios were measured by checkerboard dilution method. The synergism was determined through analysing the MIC distribution curve on isobologram and calculating the fractional inhibitory concentration index(FICI). MICs of GM, AK, MX, CFZ and CTZ against the 31 tested strains were distributed from $12.5{\mu}g/ml$ to $800{\mu}g/ml$, from $0.8{\mu}g/ml$ to $25{\mu}g/ml$, from $3.1{\mu}g/ml$ to $50{\mu}g/ml$, from $3.1{\mu}g/ml$ to $400{\mu}g/ml$, and from $12.5{\mu}g/ml$ to $100{\mu}g/ml$, respectively. The rate synergism of each drug combination by means of FICl was 45.5% in GM-MX, 36.4% in GM-CFZ, 63.6% in GM-CTZ, 48.6% in AK-MX, 35.3% in AK-CFZ, and 35.7% in AK-CTZ combination. Thus, it is suggested that Pseudomonas aeruginosa may effectively be inhibited by various aminoglycoside and cephalosporin combinations.