Chemical Research in Chinese Universities

Cover and Content of Chemical Research in Chinese Universities Vol.26 No.5(2010)

2010, 26(5): 0.

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Characteristics of ZnO Particles Prepared by Au-catalyzed Phase Transport Technique

HU Shi-qi, HUANG Ke-ke, HOU Chang-min, YUAN Hong-ming, HU Bin and FENG Shou-hua*

2010, 26(5): 675-677.

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ZnO particles were prepared by Au-catalyzed vapor phase transport method on silicon substrate. Scanning electron microscopy(SEM) images show many ZnO particles were formed on the sample surface. They grew up layer by layer along the c-axis, which was confirmed by the results of X-ray diffraction(XRD). The morphology of ZnO particles is close to hemisphere and its formation process could be seen from the SEM image. The room temperature photoluminescence(PL) measurement revealed a narrow UV emission peak at 3.27 eV and a broad green emission peak at 2.45 eV, which was caused by the near-band-edge and deep-level emissions.

Controllable Synthesis of CaCO3 Micro/Nanocrystals with Different Morphologies in Microemulsion

YU Dong1,2, CHU Ying1*, DONG Li-hong1 and ZHUO Yu-jiang1

2010, 26(5): 678-682.

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Lens-like vaterite CaCO3 microrings composed of CaCO3 nanoparticles were synthesized via a microemulsion-mediated route at room temperature with ethanol and n-hexanol as co-surfactant. This process did not demand any additional energy such as heating or continuous agitation. It was the first time to use ethanol as co-surfactant in the synthesis of micro or nanomaterials. And the ethanol was believed to play an important role in the aggregation fashion of CaCO3 nanoparticles. Moreover, shuttle-shaped nanorods, hexagonal nanoplates, and rice-like nanoparticles were also fabricated by modulating the growth parameters. Additionally, the introduce of ethanol into microemulsions as co-surfactant may be generalized as a novel green route to control the structure of other functional materials.

Three New Polyoxometalates Derivatives Decorated by Phenanthroline and Transition-metal Cations(M=ZnII, CoII, NiII)

ZHANG Yong-feng, JIA Yan-yan, NIE Hai-liang, YAN Xing-juan, WANG Li and HUANG Ru-dan*

2010, 26(5): 683-686.

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Three new Keggin polyoxometalates, [Zn(phen)3]2[SiW12O40]·5H2O(1), [Co(phen)3]2[SiW12O40](2) and [Ni(phen)3]2[SiW12O40]·2H2O(3)(phen=1,10'-phenanthroline) have been hydrothermally synthesized and characterized by elemental analysis, IR, crystal X-ray diffraction, thermogravimetric analyses(TGA) and fluorescence techniques. Complex 1, crystallized in the triclinic space group P1??, consists of one [SiW12O40]4– anion, two discrete [Zn(phen)3]2+ cations and five crystal water molecules. Complexes 2 and 3 have the similar configuration to complex 1, but they crystallized in the monoclinic space group C2/c. Variable-temperature magnetic susceptibilities of complexess 2 and 3 reveal antiferromagnetism and ferromagnetism, respectively.

Synthesis, Structure and Properties of Tren-Schiff Base Compound and Its Manganese(III) Complex by Original Self-assembly Reaction

ZHAO Hai-yan1, LI Jing1, XING Yong-heng1*, PU Zhi-feng2, BAI Feng-ying1, GE Mao-fa2 and NIU Shu-yun1

2010, 26(5): 687-692.

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The new self-assembly tripodal hexadentate Schiff base compound, C27H30N4O3, derived from tris(2-aminoethyl)amine(tren) with salicylaldehyde and its manganese(III) complex [(C27H27N4O3)Mn]·CH3OH(1) were designed and synthesized by original self-assembly reaction at room temperature in the solution of methanol. Both the compounds were characterized by elemental analysis, IR spectrometry, UV-Vis spectroscopy and X-ray single crystal diffraction. It is noteworthy that the tripodal hexadentate Schiff base ligand effectively encapsulates the manganese(III) ion and enforces a six-coordinate geometry in complex 1 with the apical nitrogen atom of tren-Schiff base remaining unbound to the metal. It is found that there are several intra-molecular hydrogen bonds in them(C—H···O and O—H···N). In addition, quantum chemistry calculations were also performed and discussed in detail. These results are consistent with the structural analyses of them.

Interaction of Mixed Porphyrin-polypyridyl Ru(II) Complex with Bovine Serum Albumin

XU Lei1, LIU Ya-nan1, MEI Wen-jie1,2, HUANG Xiao-mei2, CHEN Tian-feng1, LIU Jie1* and ZHENG Wen-jie1*

2010, 26(5): 693-698.

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The interactions of mixed porphyrin-polypyridyl Ru(II) complexes [m(Py-3′)TPP-Ru(phen)2Cl]+(1) and its derivatives [Nim(Py-3′)TPP-Ru(phen)2Cl]+(2) and [Cum(Py-3′)TPP-Ru(phen)2Cl]+(3)(phen=1,10-phenanthroline; m(Py-3′)TPP=5-(3′-pyridyl)-10,15,20-triphenylporphyrin) with bovine serum albumin(BSA) were investigated by fluorescence, UV-Vis and circular dichroism(CD) spectroscopies. The UV-Vis and CD spectral experiments indicated that the secondary structures of the protein were perturbed in the presence of the porphyrin Ru(II) complex and the perturbation was enhanced under the irradiation with ultra-violet light. The fluorescence quenching mechanism of BSA by the three complexes was determined to be a static process, and the apparent binding constant K values for complexes 1, 2 and 3 measured by fluorescence quenching method were (3.86±0.03)×103 L/mol(n=0.94±0.04), (5.69±0.04)×103 L/mol(n=1.03±0.06), and (6.54±0.02)×103 L/mol(n=1.03±0.05), respectively.

Concentrated Fluoride-medium Route to Synthesis of One-dimensional Fluoroaluminophosphate Chain (C4H15N3)[AlPO4F2]

LIU Yang, HAN Yi-de, LI Yi, SONG Xiao-wei, LI Ji-yang*, YU Ji-hong and XU Ru-ren

2010, 26(5): 699-701.

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A new one-dimensional(1D) fluoroaluminophosphate chain(C4H15N3)[AlPO4F2](denoted AlPO-CJ28) was synthesized in the concentrated fluoride synthetic medium with a gel composition of 1.0Al(OPri)3:1.0H3PO4: 5.4DETA:1.3HF:2.0H2O(DETA=diethylenetriamine). The reagents were mixed directly without introducing additional water solvent. The 1D chain is constructed by alternating AlO2F2 and doubly bridging PO4 tetrahedra to form the simplest serrate chain. AlPO-CJ28 can be transformed to another 1D aluminophosphate chain AlPO-CSC upon further crystallization at 230 °C.

Hydrogen-bonding Networks in Cocrystal of Melamine and 4-Fluoro-benzoic Acid

ZHANG Xiu-lian*, YIN Wei and CAO Man-li

2010, 26(5): 702-706.

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A novel interpenetrating structure [(HMA+)(FB–)]·2H2O of melamine(MA) with 4-fluoro-benzoic acid (HFB) was synthesized. It crystallized in the monoclinic system with space group P21/c. The complex has a interpenetrating 2D structure with hydrogen-bonded grid networks. Carboxylic acid to melamine proton transfer occurs in the complex. The adjacent HMA+ cations related by an inverse center form cationic [HMA+]∞ ribbons via a pair of N―H???N hydrogen bonds. Adjacent FB– anions are paired by C―H???F hydrogen bonds to form dimers, which are connected to [HMA+]∞ ribbons through N―H???O interactions. The supramolecular features in the complex are guided by control of strong N―H???N, N―H???O and O―H???O hydrogen bonds, as well as highly directional weak C―H???F interactions and aromatic ? ???? stacking interactions.

Hexagonal and Orthorhombic Perovskite Phases of ErMnO3 and TmMnO3 from Hydrothermal Systems

ZHU Lin-lin1, CHEN Yan1, HUANG Ke-ke1, ZHANG Gang-hua1, HU Wei-wei1, YUAN Hong-ming1, CHANG Hai-bo1,2 and FENG Shou-hua1*

2010, 26(5): 707-711.

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The powder crystals of RMnO3(R=Er, Tm) with hexagonal and orthorhombic structures were prepared under hydrothermal conditions. The different structural phases of the title compounds were controllably formed from different kinds of precursors at different reaction temperatures. All of the samples were characterized by powder X-ray diffraction, scanning electron microscopy, inductively coupled plasma analysis, and variable temperature magnetic susceptibility. Their structures were refined by Rietveld method from powder X-ray diffraction data. The measurement of magnetic behavior shows antiferromagnetic orderings at Neel temperatures around 80 and 40 K for the hexagonal and orthorhombic phases, respectively.

Liquid Chromatographic Assay of Peptides Activity with Inhibiting Angiotensin Converting Enzyme

LIU Jing-bo1, YU Zhi-peng1, ZHAO Wen-zhu1, LU Jing1, CHEN Feng2 and LIN Song-yi1*

2010, 26(5): 712-716.

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A rapid, simple and interference-free method was developed to evaluate the inhibitory activity of hydrolyzed peptides from egg white protein against the angiotensin-converting enzyme. The total reaction volume was 60 μL, saving the cost. The assay was based on a HPLC separation and quantification of the synthetic substrate hippuryl-L-histidyl-L-leucine and its hydrolyzed product―hippuric acid; the separation was performed on a C18 column eluted by a mobile phase of acetonitrile/water(0.5% TFA) at a volume ratio of 25:75. At a signal to noise ratio(S/N) of 10, the detective limit of the quantitation of hippuric acid was (0.4600±0.0097) μmol/L. The standard curve shows a linear response with a slope of 49488 and a correlation coefficient of 0.9995. The assay was adequate for the study of ACE inhibition by Captopril and peptides derived from food protein, and showed a very good correlation with the previous methods.

Systemic Nuclear Proteomics Researches on Change of Jurkat T Lymphocyte Cells Under Radiation

LIANG Feng1, LIU Zhong-ying1, LIU Ning2, SONG Feng-rui2, ZHANG Xuan3* and LIU Zhi-qiang2*

2010, 26(5): 717-722.

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Radiation causes severe constraint on numerous pathological functions of cells, such as cell growth, nuclear genetic material expression and cell functions. In this study, we performed proteomic profiling of a nuclear fraction of Jurkat T lymphocyte cells under radiation along different time course by means of 2DE and MALDI TOF-MS. We found 24 protein spots whose expression had changed after radiation, including relevant proteins, genetic material proteins, metabolism proteins, molecular chaperon and nuclear membrane proteins. Based on the above it is concluded that the combination of fluorescence labeled 2D-PAGE and MALDI-TOF MS is more precisely and effectively to elucidate the protein changes in Jurkat T lymphocyte cells after irradiation.

Direct Electrochemistry and Electrocatalysis of Hemoglobin at PAMAM Dendrimer-MWNTs-Au Nanoparticles Composite Film Modified Glassy Carbon Electrode

LIU Xing-mei1, ZHANG Xue-yu1, ZHAO Yi-li2, LIU Wei-lu1, WANG Bao-jun1, ZHANG Yi-hua1 and ZHANG Zhi-quan1*

2010, 26(5): 723-728.

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The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E0') of Hb was –0.105 V versus SCE, the electron transfer rate constant was 4.66 s–1. E0′ of Hb at the modified electrode was linearly varied in a pH range of 5.0—8.0 with a slope of –49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0×10?6 to 2.2×10?3 mol/L. The detection limit was 2.0×10?7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Kmapp) was 2.95 mmol/L.

Comparison of Adsorption Isotherms of Methylxanthines on C18 Column

BI Wen-tao1, CHOI Dae Ki2 and ROW Kyung Ho1*

2010, 26(5): 729-734.

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A comparison of the adsorption isotherms of caffeine, theophylline and theobromine and the competitive adsorption of the three compounds on a C18 column were investigated. The experimental parameters of the equilibrium isotherms were estimated by linear and nonlinear regression analyses. The linear equation as a function of the adsorption concentration of the single compound in its solution and the competitive adsorption of a single compound in a mixed solution were then determined. The adsorption equilibrium data were then correlated to the linear, Langmuir, Freundlich, Langmuir-Freundlich and stoichiometric displacement theory for adsorption(SDT-A) isotherm models. The mixed compounds of the three compounds were competitively adsorbed on the C18 particles. The expression of stoichiometric displacement theory for adsorption was found to be more suitable for adsorption of methylxanthines on a C18 column.

Qualitative and Quantitative Analysis for the Quality Control of Rhizoma Coptidis by HPLC-DAD and HPLC-ESI-MS

DOU Sheng-shan1, ZHU Shuang-lai1,3, DAI Wei-xing1, ZHANG Wei-dong1,2, ZHANG Yi4 and LIU Run-hui1*

2010, 26(5): 735-741.

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For quality control purpose, an approach of fingerprinting and simultaneous quantification of five major bioactive constituents of Rhizoma Coptidis was established via a high-performance liquid chromatograph coupled with a photodiode array UV detector(HPLC-DAD) and an electrospray ionization mass spectrometer(HPLC-ESI/MS). The compounds were identified on the basis of the comparison of their mass spectra with literature data and those of standard samples and quantified by the HPLC-DAD method. Baseline separation was achieved on an XTerra C18 column(5 μm, 250 mm×4.6 mm i. d.) with linear gradient elution of formate buffer(consisting of 0.5% formic acid, adjusted to pH=4.5 with ammonia) and acetonitrile(consisting of 0.2% formic acid and 0.2% triethylamine). The method was validated for linearity(r2>0.9995), repeatability(RSD<3.1%), intra- and inter-day precision(RSD<1.8%) with recovery(99.9%―105.1%), limits of detection(0.15―0.35 μg/mL), and limits of quantification(0.53―0.82 μg/mL). The similarities of 32 batches of Rhizoma Coptidis and their classification according to their manufacturers were based on the retention time and peak areas of the characteristic compounds. The five compounds were selected for quality assessment of Rhizoma coptidis via partial least squares analysis(PLS).

Analysis of Vitamin K3 by a Fluorescent Spectroelectrochemistry Method

ZHAO Chang-zhi*, LI Ying, DU Hong, XU Hua-jun and JIAO Kui

2010, 26(5): 742-745.

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A simple and sensitive spectroelectrochemistry method for the determination of vitamin K3 was developed by combining electrolysis and fluoremetry. This method was based on that vitamin K3 was reduced at a glassy carbon electrode, and its product with characteristic fluorescence at 420 nm was determined with excitation wavelength at 309 nm. Under optimized electrochemical reaction conditions and fluorescent experiment parameters, the fluorescence intensity was proportional to the concentration of vitamin K3 in a range from 3.50×10?7 to 1.05×10?5 mol/L with a correlation coefficient of 0.9991, and detection limit was estimated to be 7.50×10?8 mol/L at a signal/noise ratio of 3. The relative standard deviation was less than 4.3%(n=5) and the recovery was in a range of 97%―105% for the determination of vitamin K3 in pharmaceutical preparations. The result is satisfactory for the determination of vitamin K3 as comparison to that from HPLC method.

New Spirostanol Sulfonate from the Rhizomes of Helleborus thibetanus(Ranunculaceae)

YANG Feng-ying1, SU Yan-fang1,2*, ZHANG Xiao1, TU Guang-zhong3, GAO Xiu-mei2 and ZHANG Bo-li2

2010, 26(5): 746-748.

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A new spirostanol sulfonate, spirost-5,25(27)-dien-1β,3β-diol 1-sulfonate(1), was isolated from the rhizomes of Helleborus thibetanus(Ranunculaceae), and the structure was identified on the basis of a detailed spectroscopic analyses, including 2D NMR spectrometry, IR and HRESI-MS.

New Practical Synthesis of Tetrahydronquinolin-2,5-diones

XIA De-xing, FENG Chun, WANG Qiu-yan, LU Cui-fen*, CHEN Zu-xing and YANG Gui-chun

2010, 26(5): 749-752.

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A series of 4,6,7,8-tetrahydro-2,5-(1H,3H)-quinolinediones was prepared from ethyl-2-cyanoacetate, aromatic aldehydes and 1,3-cyclohexanedione or 5,5-dimethyl-1,3-cyclohexanedione by two steps, the yields were moderate to excellent. This method is a new practical promising green strategy to synthesize tetrahydronquinolin-2,5-diones.

Synthesis and Biological Activity of Novel Spin Labeled Derivatives of 4'-Demethyl-4-deoxypodophyllotoxin

XU Jing, SUN Xiao-hua, ZHANG Jia-qiang, ZHANG Zhi-wei and TIAN Xuan*

2010, 26(5): 753-756.

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Seven novel spin labeled derivatives of 4'-demethyl-4-deoxypodophyllotoxin with nitroxyl radicals(TMHPO and TMPRO) were prepared and their cytotoxic and antioxidative activities were tested. Their cytotoxic activities were tested against two tumor cell lines(A-549 and HL-60) in vitro. Among them, five compounds show higher inhibition activity against A-549 cells compared with the clinical drug VP-16(2) and parent compound 4'-demethyl-4-deoxypodophyllotoxin(DDPT, 6). Compounds 8, 10 and 13 show excellent inhibition activity against HL-60 cells. Furthermore, the antioxidative activities of them were tested. All the seven spin labeled compounds show stronger antioxidative activity compared with VP-16(2) and DDPT(6). The partition coefficients P of these derivatives were determined.

Brand-new Function of Well-designed Ionic Liquid: Inhibitor of Tumor Cell Growth

ZHANG Zhong-bo3, FU Shi-bo2, DUAN Hai-feng1, LIN Ying-jie1* and YANG Ying2*

2010, 26(5): 757-760.

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An investigation into the effect of several novel well-designed guanidinium salt ionic liquids(GILs) on inhibitting tumor growth is described. The GILs which have longer alkyl chain(6―18 carbon atoms) exhibit the high cytotoxicity to Hela299, B16 and SMMC-7721 cells so as to inhibit their proliferation. The inhibitory effect of the most effective GIL12 is about 10-fold higher than that of MMC(a common chemotherapy drug in clinic).

Synthesis and Langmuir-Blodgett Film Analysis of Atropisomers of “Picket Fence” Porphyrin

WANG Chao-wei2, REN Yu-jie1*, CAO Zhen-feng2 and CHEN Qi-bin2*

2010, 26(5): 761-767.

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Four “picket fence” porphyrin atropisomers were respectively synthesized from the four corresponding atropisomers of meso-tetra(o-aminophenyl)porphyrin that had been chromatographed on a column eluted with petroleum ether and ethyl acetate. Results show that each atropisomer could be successfully synthesized by controlling the acylation temperature at 0 °C. They were characterized by 1H NMR, HRMS, IR, UV-Vis and Langmuir-Blodgett(LB) film analyses. Although the results of HRMS, IR, UV-Vis analyses indicate there is no remarkable difference among the atropisomers, the results of the 1H NMR and the mean molecular areas obtained by LB film technique imply that the atropisomers are significantly discrepant. The former shows that the chemical shifts of the methyl and amide protons of each atropisomer are distinct, while the later presents that the different atropisomer molecules can occupy the different surface areas at the air/water interface.

Synthesis of Di-substituted Proazaphosphatrane and Its Application in Carbon-carbon Double-bond Isomerization

WU Wei*, ZHANG Xiao-yun and KANG Shou-xing

2010, 26(5): 768-772.

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Diisopropyltren was synthesized from the reaction of tren with benzaldehyde in toluene, followed by reducing the imine intermediate with NaBH4, and debenzylation catalyzed by 10% Pd/C in methanol. It was then converted to its corresponding azaphosphatrane via ring-closing reaction of HMPT and triflic acid. Deprotonation of azaphosphatrane with potassium t-butoxide afforded the target diisopropyl proazaphosphatrane 1d. A comparative study of compound 1d for isomerization of allylic system and methylene-interrupted diene system revealed that compound 1d is more efficient than its tri-substituted analoque(1b). In acetonitrile at 40 °C, allylaromatics were selectively isomerized to 1-arylpropene generally in an isolated yield more than 95% with trans, cis molar ratios in a range of 87/13 to 96/4. Allyl phenylsulfide was converted to 1-phenylthiopropene(molar ratio of Z/E=54/46) in a yield of 93%―95%. Methylene-interrupted dienes were also isomerized in high yield.

Expression of CTB-human Insulin(BA) Fusion Protein in Gynostemma Pentapyhllum Makino Callus Cells and Its Hypoglycemic Effect in Mice

WANG Ya-jun1,2, QI Feng-chun2, HAO Shu-mei3, WANG Chun-yi2, SUI Bo4 and SHENG Jun1,2,5*

2010, 26(5): 773-779.

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The plant expression vector of choleratoxin B subunit(CTB)-human insulin(BA) fusion protein pBI121/(CTB-BA) was constructed first and then the Gynostemma Pentapyhllum Makino callus cell line that could express CTB-human insulin fusion protein was constructed and its hypoglycemic effect was evaluated in mice. The plant expression vector pBI121/(CTB-BA) was digested with both BamI and SacI. Agrobacterium tumerfaciens strain LBA4404 was transformed with previously constructed recombinant plasmid pBI121/(CTB-BA) via the freeze tha- wing method, then CTB-BA gene was integrated to G Pentapyhllum Makino callus cells by co-culturing the cells with the transformed LBA4404 strain. The transformed G Pentapyhllum Makino callus cells were identified by DNA sequence assey and RT-PCR. The expressed product was identified by western-blot and its amount was tested by ELISA kit and its blood sugar decreasing effect was tested in mice．The sequences of synthetic CTB and human insulin genes(BA) were completely identical to those designed. Restriction map proved that the length of gene fragment inserted into expression vector pBI121 was consistent with that expected. The sequence of genomic DNA of expressed product was completely identical to that designed. The result of RT-PCR was consistent with that expected. The expressed product showed a specific band with a relative molecular mass of 17000 by Western-blot. The human insulin expression amount was 6.03 ?IU/mL according to the ELISA result．The animal test showed that only the G Pentapyhllum Makino callus cell line itself showed activity in decreasing the blood sugar of mice, however, the activity of the transformed G Pentapyhllum Makino callus cells was much higher. The plant expression vector pBI121/(CTB-BA) was constructed and expressed in the G Pentapyhllum Makino callus cells successfully for the first time. The transformed G Pentapyhllum Makino callus cells showed high activity in decreasing the blood sugar of mice. This study developed a new way for the development of oral administration insulin.

Preparation, Release-control and Cell Apoptosis of C6 Glioma Cells in PEG-PLGA-Rg3 Nanoparticles

BIE Li1, YUAN Hong-yan2, WANG Xin3, ZHAO Gang1* and LIU Xing-ji1*

2010, 26(5): 780-784.

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With biodegradable material poly(ethylene glycol)-poly(lactide-co-glycolide) (PEG-PLGA) as substrate, the size distribution of Rg3-NPs was approved by the scanning electron microscopy. MTT assay was used to detect the effects of Rg3-NPs on the growth rate of C6 cells at various concentrations and flow cytometry(FCM) was applied to assay the cell cycle and cell apoptosis of C6 glioma cells. Western blot analysis was used to measure the protein level of PCNA. The results show that Rg3-NPs are slick and uniformity, the average diameter of the nanoparticles is about 75―90 nm, entrapment efficiency is (89.7±1.7)%. MTT assay shows the growth of C6 Glioma Cells can be significantly inhibited by Rg3-NPs in a dose-dependence manner. FCM and Western blot analysis show Rg3 can be released from the conjugated nanoparticles to function in the cell nuclei so as to lead to the changes in the growth cycle of the cells, which results in the arrest of G0-G1 cell cycle and induces the apoptosis of C6 cells. Therefore, Rg3-NPs may be used for the auxiliary therapy of brain glioma.

Regulating Effect of Allicin(Diallyldisulfid-S-Oxide) on Respiration Function of Mitochondria from Beef Heart

SU Yan-bin1,2, TONG Li-fang3, LIU Pai1, LU Ming1, CHENG Ying-kun1, ZHANG Feng-rong4, SU Yan-wen2, DONG Jia-ning1 and LI Zheng-qiang1*

2010, 26(5): 785-791.

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To probe into regulating functions of allicin, diallyldisulfid-S-oxide, on electron transport in the inner membrane of mitochondria isolated from beef heart, under the anaerobic, hypoxia, and oxygenating conditions in the presence of rotenone(complex I inhibitor) at 37 °C, we optimized the isolation method for isolating mitochondria from beef heart and used the technique for measuring dissolved oxygen content at the right moment so as to investigate the effects of allicin on the respiratory control of mitochondria in state 4 and state 3, P/O ratio, and respiratory control ratio(RCR). The results show that the optimized isolated requirements were that all the operations were always kept at 0―4 °C, the ratio between sample and isolation medium was 1:4, the filter was a four-layer gauze, two centrifugations in different sections. First section: 2500g, 10 min; second section 7000g, 20 min. The results indicate that the capacity of dissolved oxygen in state 3 was increased and that of dissolved oxygen in state 4 was almost stabilized in mitochondria from beef heart.

Caspase-9 Activation—Critical for Betulin-induced Apoptosis of Human Hepatoma Cells

LI Yang1 , SHEN Jared Taiyi1, GAO Chang1, LI Qing2 and JIN Ying-hua1*

2010, 26(5): 792-797.

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Betulinic acid and its derivatives have been extensively studied in the past for their anti-tumor effects, but relatively little is known about its precursor betulin. In this study we showed that betulin, an abundant natural product, significantly inhibits the cell growth of human hepatoma HepG2 cells in a dose-dependent manner. In the presence of 10 ?g/mL betulin, HepG2 cells undergo an apoptosis, as evidenced by apoptotic morphology such as cell shrinkage, membrane blebbing, nuclear condensation and fragmentation, apoptotic body formation, and caspase activation. Kinetics analysis shows that the depolarization of the mitochondrial membrane potential and the release of the mitochondrial apoptotic protein cytochrome c occurred as early as 2 h post treatment of HepG2 cells with 10 ?g/mL betulin. Proteolytic activation of caspase-9, but not caspase-8, was observed in this apoptosis process. Moreover, the inactivation of caspase-9 by its specific siRNA dramatically reduced betulin-induced caspase-3 activation and apoptosis. Taken together, our observations indicate that the activation of caspase-9 is critical for betulin-induced apoptosis of human hepatoma HepG2 cells.

Extraction, Purification and Anti-tumor Activity of Polysaccharide from Mycelium of Mutant Cordyceps Militaris

ZHANG Ai-li, LU Jia-hui, ZHANG Na, ZHENG Dan, ZHANG Gui-rong* and TENG Li-rong*

2010, 26(5): 798-802.

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A water-soluble polysaccharide(named MCMP) was isolated from the mycelium with high yield mutation Cordyceps militaris by hot-water extraction, deproteinization by sevage, alcohol precipitation, anion-exchange and gel filtration chromatography CL-6B. The polysaccharide contained mannose, rhamnose, galactose and glucose in a molar ratio of 59.36:1:8.31:39.50, of which the average molecular weight is 8100. In our research, Hep-G2 cells, Hela cells and mesangial cells were chosen to determine the anti-tumor activity of the polysaccharide. The results of MTT assay show that polysaccharides of the mutant strain presented inhibitory activity on the cells proliferation after 48 h incubation.

Prediction of miRNA Based on miRNA Biogenesis via One-class SVM

LIU Yuan-ning1,2, YAN Wen1,2, ZHANG Hao1,2*, LI Zhi4, LU Hui-jun3 and LI Xin1,2

2010, 26(5): 803-809.

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MicroRNAs are a class of small, single-stranded RNAs which are produced by non-protein-coding RNA genes with a length of 21—29 nt. They regulate the expression of protein-encoding genes at the post-transcriptional level and the degradation of mRNAs by base pairing to mRNAs. Mature miRNAs are processed from 60—90 nt RNA hairpin structures called pre-miRNAs. At present, most of the machine learning computational methods for pre-miRNAs prediction are based on two-class SVM and use structural information of pre-miRNA hairpins. Those methods share a common feature that all of them need a negative dataset in the training dataset and feature selection in both training and testing dataset. In order to avoid selecting false negative examples of miRNA hairpins in the training dataset which may mislead the classifiers, we presented a microRNA prediction algorithm called MirBio based on miRNAs Biogenesis which is trained only on the information of the positive miRNAs class to predict miRNAs. It can predict both pre-miRNAs and miRNAs and get a relatively satisfying result in this study.

Immunization Schedule of Liposomal Rabies Vaccine in Animals

GUO Xiu-xia1,2, YAN Liang2, YANG Yi2, YUAN Ruo-sen2, LIU Yan2 and SHENG Jun1,2*

2010, 26(5): 810-815.

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The standard rabies vaccines recommended by WHO include Essen regimen, the Thai Red Cross two-site ID regimen and the eight-site ID regimen, and so on. The present schedules of rabies vaccine are all laborious and time consuming. We developed a new rabies vaccine with liposome as adjuvant(LipoRabV) and found that liposome could facilitate the inactivated rabies vaccine(RabV) to induce the more vigorous production of rabies virus neutralizing antibody(RVNA) in BALB/c mice and beagles. We established preliminary pre- and post-exposure prophylaxis schedules for LipoRabV. LipoRabV(0/14) could elicit similar RVNA level as RabV(0/7/28) by pre-exposure prophylaxis schedules in mice and beagles. LipoRabV(0/3/14) could elicit higher RVNA level vs. RabV(0/3/7/14/28) in BALB/c. The data indicate that the three-shot liposome-enhanced rabies vaccine could achieve a higher protection rate(survival rate 56.2%) by post-exposure prophylaxis compared with that of the RabV group(survival rate 40.6%) in mice. The data also indicate that the three-inoculation liposome-enhanced rabies vaccine could achieve a survival rate of 80.0% vs. RabV(70.0%) by post-exposure prophylaxis in beagles. The results show that the immunization schedule for LipoRabV could be preliminarily determined at 0 and 14 d for pre-exposure prophylaxis and at 0, 3 and 14 d for post-exposure prophylaxis.

Analysis of a Critical Residue Determining Herbicide Efficiency Sensitivity in Carboxyltransferase Domain of Acetyl-CoA Carboxylase from Poaceae by Homology Modeling and Free Energy Simulation

TAO Jin, ZHAO Bo, TIAN Xue-mei, ZHENG Liang-yu* and CAO Shu-gui*

2010, 26(5): 816-821.

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Carboxyltransferase domain(CT) of acetyl-coenzyme A carboxylase(ACCase, EC 6.4.1.2) from a family of Poaceae is an important target of commercial herbicide APPs for controlling grass weed growth. As the abuse of APPs herbicides, the resistant ACCase due to the mutation of a single residue(Ile→Leu), which is located in CT active site, is emergent in many populations and species of Poaceae. So it is urgent to understand the resistant mecha- nism so as to design new effect herbicides. Herein lies the complex of CT dimmer from Lolium rigidum and herbicide haloxyfop successfully constructed for wild type enzyme and Ile/Leu mutant, respectively, providing a basis for explaining the resistance from microscopic structure. Moreover, the binding free energy difference between wild type and mutant enzymes was predicted in good agreement with the known observation, and the various contributions to it were analyzed, by Molecular mechanics-Poisson-Boltzmann surface area(MM-PBSA) method. The results indicate the van der Waals interaction difference between the protein and inhibitor, –22.94 kJ/mol of CT wild type lower than that of mutant, is the major reason for resistance. Structure analysis further suggests that van der Waals interaction difference is originated from the steric hindrance between the side chain of mutated residue Leu and the chiral methyl group of haloxyfop. All these findings enhance the understanding of resistant mechanism of ACCase to herbicide by Ile/Leu mutation and provide an important clue for the rational design of high effective herbicides.

Numerical Simulation for Crevice Corrosion of 304 Stainless Steel in Sodium Chloride Solution

WANG Wei1,2,3, SUN Hu-yuan1,2*, SUN Li-juan1,3, SONG Zu-wei1,2,3 and ZANG Bei-ni1,2,3

2010, 26(5): 822-828.

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The authors presented a mechanistic model describing the chemical reactions within a corroded thin, narrow crevice. In the mathematical model, a two-dimensional steady-state was used to predict the crevice pH profile by taking into account dissolved oxygen and hydrogen ions within the crevice. It consists of six parallel electrochemical reactions: multi anodic reactions(Fe, Cr, Ni dissolution reactions) and three cathodic reactions(the oxygen reduction, the hydrogen reaction and water dissociation). Current density distribution and oxygen concentration distribution were determined to be corresponding to the evolution of potential distribution within the crevice. The contribution of each metal reaction to the overall corrosion process was in proportion to the mole fraction, and the simulation provided a good agreement with published experimental results for the crevice corrosion of stainless steel in sodium chloride solution.

Estimation of Critical Temperature of Thermal Explosion for Energetic Materials Based on Non-isothermal Kinetic Equation dα/dt =A0exp(bT)[1+(T–T0)b]f(α)

ZHAO Feng-qi1*, HU Rong-zu1,2, ZHANG Hai2,5, GAO Hong-xu1, ZHAO Hong-an3 and MA Hai-xia4

2010, 26(5): 829-832.

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Critical temperature(Tb) of thermal explosion for energetic materials is estimated from Semenov’s thermal explosion theory and the non-isothermal kinetic equation dα/dt=A0exp(bT)[1+(T–T0)b]f(α) deduced via reasonable hypotheses, where T0 is the initial point of the deviation from the baseline of DSC curve. The final formula is (Tb–Te0){1+1/[1+( Tb–T00)b]}=1. We can easily obtain the initial temperature(T0i) and onset temperature(Tei) from the non-isothermal DSC curves, the values of T00 and Te0 from the equation T0i or ei=T00 or e0+α1βi+α2βi2+…+αL–2βiL–2, i=1,2,…,L, the value of b from the equation: ln[βi/(Tei–T0i)]=ln[A0/G(α)]+bTei, so as to calculate the value of Tb. The result obtained with this method coincides completely with the value of Tb obtained by Hu-Yang-Liang-Wu method.

Insight into Reaction Mechanism of Sirtuins via Molecular Simulation and Density Functional Theory Study

ZHAO Yong-shan1,3, HOU Rui-zhe2, ZHANG Hong-xing1, ZHENG Qing-chuan1* and SUN Chia-chung1

2010, 26(5): 833-837.

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