检索结果-南通市图书馆

Tobacco-specific Carcinogen 4-(Methylnitrosoamino)-1-(3-pyridyl)-1-butanone(NNK) Activating ERK1/2 MAP Kinases and Stimulating Proliferation of Human Mammary Epithelial Cells

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2007年第1期23卷 76-80页

作者： CHEN Zhi-bo AN Yang WANG Zhe ZHANG Bo-xun liu lan-ying College of Life Science Jilin University Changchun 130021 P. R. China College of Life Science and Engineering Qiqihar University Qiqihar 161000 P. R. China Department of Internal Medicine of Digestion China-Japan Union Hospital Jilin University Changchun 130033 P. R. China

Cigarette smoking is correlated with the development of various cancers. 4- （Methylnitresoamino） -1- （3-pyridyl） - 1-butanone（NNK） is one of the major tobacco-specific carcinogens in the cigarette smoke, which increases the risk of breast cancer. In the present study, it was demonstrated that NNK rapidly activated ERK1 and ERK2 MAP kinases in human normal mammary epithelial cells. It was found that there are two different routes for the activation of ERK1/2 with NNK. One is from nicotinic receptor nAchR to MEK1/2, and the other is from tyrosine kinase containing receptor to MEK1/2. The tobacco-specific carcinogen NNK shows a strong proliferative effect on normal human mammary epithelial cells and cancer mammary epithelial cells.

关键词： Mammary epithelial cells NNK ERK MAPK Nicotinic receptor nAehR Tyrosine kinase Signaling pathway Carcinogen Cell proliferation

Changes in Texture and Retorting Yield in Oil Shale During Its Bioleaching by Bacillus Mucilaginosus

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2013年第2期29卷 294-298页

作者： ZHANG Xue-qing REN He-jun liu Na ZHANG lan-ying ZHOU Rui Key Lab of Groudwater Resources and Environment Ministry of Education College of Environment and Resources Jilin University Changchun 130012 P. R. China

Bioleaching of oil shale by Bacillus mucilaginosus was carried out in a reaction column for 13 d. The pH value of the leaching liquor decreased steadily from 7.5 to 5.5 and the free silicon dioxide concentration reached approximately 200 mg/L in it. Scanning electron microscopy（SEM） observations revealed that a mass of small particles separated from the matrix of oil shale. Energy dispersive spectrometry（EDS） analysis implied that the total content of Si,O, A1 was decreased in the particle area of the matrix. These facts indicate that the silicate was removed, leading to the structural transformation of oil shale. Comparison of the shale oil yields before and after bioleaching illustrated that approximately 10% extra shale oil was obtained. This finding suggests that the demineralisation of the oil shale by silicate bacteria improves shale oil yield.

关键词： Oil shale Bacillus mucilaginosus Bioleaching Shale oil yield

Purification and Characterization of Superoxide Dismutase(SOD) from Camellia Pollen

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第5期21卷 558-561页

作者： HE Xiao-hong WU Min LI Shan-yu FAN Hao CHU Yu-zhuo liu lan-ying College of Life Science Jilin University Changchun 130023 P. R. China

A superoxide dismutase（ SOD ） was purified to homogeneity from fresh camellia pollen by means of ammonium sulfate precipitation and column chromatography with DEAE-cellulose（ DE52 ）, Sephadex G-100 and phenyl sepharose^TM 6 Fast Flow columns. Its specific activity could reach to 4034 U/mg protein and it was determined to be Cu/ Zn-SOD according to its different sensitivities to different inhibitors. The molecular weight of the SOD and its subunit were 69500 and 34700, respectively, based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS- PAGE）, which implicates that the SOD in camellia pollen is a dimmer composed of two identical subunits. The isoelectric point of the enzyme was determined to be 4. 1 by isoelectric focusing electrophoresis and the N-terminal amino acid was identified to be Gly by the DNS-Cl method. Its α-Helix was also calculated to be approximately 21.8% according to the circular dichroism（CD） spectra.

关键词： Camellia pollen Superoxide dismutase Purification Characterization

Chemical Modification of Tryptophan Residues in Superoxide Dismutase from Camellia Pollen and Its Fluorescence Spectrum

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第5期21卷 562-565页

作者： HE Xiao-hong WU Min LI Shan-yu CHU Yu-zhuo CHEN Jia liu lan-ying College of Life Science Jilin University Changchun 130023 P. R. China

The amino acid composition of the superoxide dismutase（SOD） from camellia pollen was measured and the tryptophan（Trp） residues were modified by using N-bromosuccinimide（NBS）. The results show that there are 21 Trp residues in an SOD molecule and seven of which are located on the surface of the enzyme. By researching the fluorescence spectra of the native SOD and the modified SOD, we have found that the emission wavelength of Trp is at 335 nm and the fluorescence intensity will decrease when the enzyme is modified. The results also show that potassium iodide（KI） can significantly quench the fluorescence of the native SOD, but it has a less pronounced effect on the modified enzyme. Glycerin as a surface activation reagent can stabilize the fluorescence of the modified enzyme.

关键词： Superoxide dismutase Tryptophan residue Chemical modification Fluorescence spectrum

Chemical Modification and Fluorescence Spectrum of Tryptophan Residues in Pullulanase

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第1期22卷 61-64页

作者： TENG Li-rong FAN Hao ZHANG Yuan-yuan YU Qi HUANG Yue-feng liu lan-ying College of Life Science Jilin University Changchun 130023 P. R. China

Tryptophan（Trp） residues in a pullulanase were modified by N-bromosuccinimide（NBS）. The results of the Spande method indicate that there are 18 Trp residues in the pullulanase and nine of them are located on the surface af the enzyme. Three of these Trp residues are nonessential residues which show the fastest reaction rate according to the Zou＇s plot. Two of the seven relative faster reacting residues are essential for the activity of the enzyme. The other eight are the slowest in the reaction rate or non-reactive residues for the reaction. The fluorescence and circular dichroism（CD） spectra of the pullulanase have been changed after the reaction with NBS. Potassium iodide（KI） and acrylamide also have remarkable influences on the fluorescence spectra of the pullulanase.

关键词： Pullulanase Tryptophan (Trp) Chemical modification Fluorescence spectrum

Purification and Properties of Superoxide Dismutase(SOD) in Allium Sativum

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2003年第4期19卷 442-445页

作者： TENG Li-rong WANG Ya-jun WU Min HONG Shui-sheng CHEN Jia Meng Qing-fan liu lan-ying College of Life Science Jilin UniversityChangchun 130023P.R.China

Superoxide dismutases(SODs) were purified to homogeneity from Allium Sativum by means of ammonium sulfate precipitation and column chromatography with DEAE-cellulose(DE52) and Sephadex G-75. Based on sodium dodecyl sulfate\|polyacrylamide gel electrophoresis(SDS-AGE), Allium Sativum is predicted to contain four SODs. The molecular weights of the native SODs are 41 3 kD, 37 0 kD, 35 2 kD and 31 0 kD, which consist of subunits of 20 7 kD, 18 4 kD, 17 7 kD and 15 4 kD respectively. Because of their specific sensitivity to hydrogen peroxide, cyanogens potassium and chloroform\|alcohol, the SODs in Allium Sativum appear to be Cu, Zn-SOD isoenzymes. The isoelectric analysis indicates that three of the four isoenzymes are acidic proteins with isoelectric points at pH 3 5, 3 7 and 4 0, respectively, and the fourth one is a basic protein with isoeletric point at pH 8 5.

关键词： Superoxide dismutase Allium Sativum Purification Properties

Rapid and Sensitive LC-MS/MS Method for Quantification of Fexofenadine in Human Plasma——Application to a Bioequivalence Study in Chinese Volunteers

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2007年第5期23卷 514-517页

作者： TENG Guo-sheng TENG Le-sheng WU Yi TANG Yun-biao liu lan-ying GU Jing-kai　 Research Center for Drug Metabolism College of Life Science School of Pharmaceutical Science Jilin University Changchun 130021 P. R. China Department of Pharmacy General Hospital of Shenyang Military Command Shenyang 110016 P. R. China

A rapid and sensitive liquid chromatography-tandem mass spectrometry method（LC-MS/MS）was developed and validated for the quantification of fexofenadine in human plasma,to conduct comparative bioavailability *** plasma was extracted with a mixture of dichloromethane-diethyl ether（volume ratio 2∶3）in a basic environment and the extract was separated on a C18 column with a mobile phase consisting of acetonitrile-methanol-10 mmol/L ammonium acetate（volume ratio 45∶45∶10）.The analytes were detected via electrospray ionization（ESI）tandem mass spectrometry in the multiple-reaction-monitoring（MRM）*** linearity was within a range of 1-1000 ng/*** intra-and inter-day precision were〈4.1% and〈4.8%,respectively,and the accuracy was in the range of 95.0%-105%.The method was applied to the quantification of fexofenadine human plasma from 20 healthy male Chinese volunteers,according to a single dose,randomized,two-way crossover design with a two-week washout *** mean values of major pharmacokinetic parameters of ρmax,AUC0-48,AUC0-∞,tmax,and t1/2 were determined from the plasma *** analysis of variance（ANOVA）did not show any significant difference between the two products of fexofenadine and 90% confidence intervals fell within the acceptable range for bioequivalence.

关键词： Fexofenadine Bioequivalence LC-MS/MS Human plasma

Preparation and Kinetics of a Novel Glutathione Peroxidase Mimic——Selenium-modified Hyaluronic Acid

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2007年第3期23卷 325-328页

作者： CHEN Jia HONG Shui-sheng AN Yang JIANG Guang-zhi ZHANG Bo-xun FANG Xiang-yang liu lan-ying TENG Li-rong College of life Science Jilin University Changchun 130021 P. R. China

A selenium-modified hyaluronic acid（HA） compound（SeHA） was synthesized as a mimic of glutathione peroxidase（GPX）. IR and NMR spectra of SeHA predict that the --CH2OH group of the N-acetyl-D-glucosamine in HA was modified by group --Sell. There are averagely 152 --Sell groups in one SeHA molecule. The GPX activities are 103.88, 32. 15 and 152. 71 U/μmol, respectively, when the substrates were H2O2, BuOOH and CuOOH. Ping-pong mechanism was observed in the steady-state kinetic studies of the reactive oxygen species（ROS） consuming reaction. Result of reactions of SeHA with free radical capturer 2,6-di-tert-butyl-4-methylphenol（BHT） shows that the catalysis is based on a non-free radical-mechanism and the SeHA can not be inhibited by iodoacetate, an enzyme inhibitor.

关键词： Selenium-modified hyaluronic acid GPX Preparation Kinetics

New progresses of fine-grained sediment gravity-flow deposits and their importance for unconventional shale oil and gas plays

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2025年第1期22卷 1-15页

作者： Tian Yang ying-Lin liu State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology) Institute of Sedimentary Geology Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology

Fine-grained sediments are widely distributed and constitute the most abundant component in sedimentary systems, thus the research on their genesis and distribution is of great significance. In recent years, fine-grained sediment gravity-flows(FGSGF) have been recognized as an important transportation and depositional mechanism for accumulating thick successions of fine-grained sediments. Through a comprehensive review and synthesis of global research on FGSGF deposition, the characteristics,depositional mechanisms, and distribution patterns of fine-grained sediment gravity-flow deposits(FGSGFD) are discussed, and future research prospects are clarified. In addition to the traditionally recognized low-density turbidity current and muddy debris flow, wave-enhanced gravity flow, lowdensity muddy hyperpycnal flow, and hypopycnal plumes can all form widely distributed FGSGFD. At the same time, the evolution of FGSGF during transportation can result in transitional and hybrid gravityflow deposits. The combination of multiple triggering mechanisms promotes the widespread development of FGSGFD, without temporal and spatial limitations. Different types and concentrations of clay minerals, organic matters, and organo-clay complexes are the keys to controlling the flow transformation of FGSGF from low-concentration turbidity currents to high-concentration muddy debris flows. Further study is needed on the interaction mechanism of FGSGF caused by different initiations, the evolution of FGSGF with the effect of organic-inorganic synergy, and the controlling factors of the distribution patterns of FGSGFD. The study of FGSGFD can shed some new light on the formation of widely developed thin-bedded siltstones within shales. At the same time, these insights may broaden the exploration scope of shale oil and gas, which have important geological significances for unconventional shale oil and gas.

关键词： Fine-grained sediment gravity-flow Depositional mechanism Transportation and evolution Distribution pattern Shale oil and gas