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Science China Chemistry 2007年第5期50卷 629-637页

作者： LIU JiangTao1,2, LIU ZhongFang1 & LIU ShaoPu1 1 School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China 2 Department of Chemistry, Fuling Normal University, Chongqing 408000, China School of Chemistry and Chemical Engineering Southwest UniversityChongqing 400715China Department of Chemistry Fuling Normal UniversityChongqing 408000China

The interaction of bleomycinA5 with nucleic acids has been investigated byusing resonance Rayleigh scattering (RRS),molecular absorption and fluorescence *** resultshows that in near pH 2.2 buffer medium and absence of any metal ions,nucleic acids are capable ofbinding with bleomycinA5 (BLMA5) to form complexes which can remarkably enhance the RRS intensityand result in batho-chromic and hyperchromic molecular absorption of nucleic acids and fluorescencequenching of *** RRS spectral characteristics for the binding products of bleomycinA5with various DNA and RNA are similar,and the maximum RRS peaks are at 301 nm for ctDNA and sDNA,370nm for hsDNA,310 nm for RNAtypeVI and RNAtypelll,*** increments of RRS intensity aregreatly different in which DNA enhances greatly and RNA enhances *** this work,the optimumconditions of the interaction and some influencing factors have been *** reactionmechanism and a binding model for the interaction of BLMA5 with the nucleic acids are ***,a highly sensitive,simple and rapid new method for the determination of DNA has *** detection limits (3 sigma) are 5.7 ng/mL for ctDNA,7.4 ng/mL for sDNA and 9.2 ng/mLfor hsDNA,*** method can be applied to determination of trace amounts of DNA.

关键词： bleomycinA5, nucleic acids, resonance Rayleigh scattering, fluorescence quenching, absorption spectrum.

Resonance Rayleigh scattering spectral characteristics of interaction of nucleic acids with some cationic surfactants and their analytical applications

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Science China Chemistry 2002年第2期45卷 173-183页

作者：刘绍璞范莉胡小莉罗红群 Institute of Environmental Chemistry Southwest China Normal University Chongqing China

In near neutral medium, the resonance Rayleigh scattering (RRS) intensities of an alone cationic surfactant and nucleic acid are very weak. However, when they combine with each other to form a complex, the RRS intensity of the solution is enhanced greatly. In this paper the reactions of five cationic surfactants with nucleic acids have been studied. The results show that the reaction conditions and RRS spectral characteristics of these reactions are similar, but their sensitivities are obviously different. Among them, the sensitivity of cetyldimethyl benzylammonium chloride (CDBAC) with an aryl and large molecular weight is the highest, while that of cetyltrimethylammonium bromide (CTAB) without aryl and with small molecular weight is the lowest. The detection limits for ctDNA and yRNA of the former are 6.6 and 29.4 ng@mL?1, while that of the latter are 13.3 and 53.6 ng@mL?1. The method has better selectivity and can be applied to the determination of trace amounts of nucleic acids. Furthermore, it is discovered in the investigation that not only the RRS intensity is related to the structure and molecular weight of the cationic surfactants, but also the change of the RRS intensity is closely related to the conformational change of nucleic acid. Therefore, the RRS method can be expanded to become a useful way to study the nucleic acid conformation.

关键词： resonance Rayleigh scattering, nucleic acids, cationic surfactant, determination.

Effects of epoxyeicosatrienoic acids on levels of eNOS phosphorylation and relevant signaling transduction pathways involved

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Science China(Life Sciences) 2005年第5期48卷 495-505页

作者： CHEN Ruijuan1, JIANG Jiangang1, XIAO Xiao2 & WANG Daowen1 1. The Institute of Hypertension and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430030, China 2. Departments of Molecular Genetics and Biochemistry & Gene Therapy Center, University of Pittsburgh, Pittsburgh, PA, USA The Institute of Hypertension and Department of Internal Medicine Tongji Hospital Tongji Medical College Huazhong University of Science & Technology Wuhan 430030 China Departments of Molecular Genetics and Biochemistry & Gene Therapy Center University of Pittsburgh Pittsburgh PA USA

Endothelial nitric oxide synthase (eNOS) is a key enzyme responsible for the regu-lation of vascular homeostasis. Many humor factors and mechanical forces can affect eNOS ac-tivity via phosphorylation modification but the mechanisms involved vary with stimuli applied. We have demonstrated that cytochrome P450 (CYP) epoxygenase-dependent metabolites of ara-chidonic acid, epoxyeicosatrienoic acids (EETs), can robustly up-regulate eNOS expression and its activity, however the relevant signaling pathways responsible for activity regulation are not well known. In this study, we explored the role of PI3 kinase (PI3K)/protein kinase B (Akt) sig-naling pathway in eNOS expression and its phosphorylation in response to EETs via direct addi-tion of EETs into cultured bovine aorta endothelial cells (BAECs) and recombinant adeno- asso-ciated virus-mediated transfection of CYP epoxygenase genes CYPF87V and CYP2C11 to pro-duce endogenous EETs followed by co-treatment with PI3K or Akt inhibitor. Results show that both exogenous and endogenous EETs could remarkably enhance eNOS expression and its phosphorylation at Ser1179 and Thr497 residues; PI3K inhibitor LY294002 could inhibit EETs-induced increase in eNOS-Ser(P)1179 but had no effect on the change of eNOS-Thr(P)497, while Akt inhibitor could attenuate the increase in phosphor-eNOS at both residues; both of the two inhibitors could block EETs-enhanced eNOS expression. These results lead to conclusions: (i) EETs-mediated regulation of eNOS activity may be related with the changes of phosphoryla-tion level at eNOS-Ser1179 via PI3K/Akt and eNOS-Thr497 via Akt; (ii) PI3K/Akt signaling pathway is involved in the up-regulation of eNOS expression by EETs.

关键词： epoxyeicosatrienoic acids, endothelial nitric oxide synthase (eNOS), PI3 kinase, Protein kinase B (Akt), phosphorylation.

Chemical compositions of precipitation and scavenging of particles in Beijing

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Science China Chemistry 2005年第3期48卷 265-272页

作者： HU Min ZHANG Jing WU Zhijun State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China

Totally 23 precipitation samples were collected in Beijing from May to November in 2003. In order to investigate the chemical composition of precipitation samples, pH, conductivity, concentrations of water-soluble ions and organic acids were analyzed. The average pH of pre-cipitations is 6.18, belonging to the neutral range; the average conductivity is 52.23 μS/cm, which indicates that precipitations in Beijing are obviously polluted; SO 24? , NO3 ? are the most abundant anions with the average concentrations of 521 and 174 μeq·L?1, respectively; the average 2SO 4? /NO3? equivalent ratio is 3.1, which decreases by about 15% compared with the result of 1994; NH+ 4 and Ca2+ are the most abundant cations with the average concentrations of 376 and 397 μeq·L?1, respectively; formic acid, acetic acid and oxalic acid are the main organic acids with the average concentrations of 4.62, 4.60 and 1.17 μeq·L?1, respectively, accounting for 2% of the overall anions. Obvious differences between concentrations before and after precipitation are also observed by SJAC (Steam Jet Aerosol Collector), which shows the removal of particles from the atmosphere by precipitation.

关键词： precipitation, particles, ions, organic acids, scavenging.

ANISODAMINE INHIBITS ENDOTOXIN-INDUCED PROSTAGLANDINS AND LEUKOTRIENES RELEASE FROM MOUSE MACROPHAGES

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Chinese Science Bulletin 1989年第24期34卷 2061-2066页

作者：麦凯岳天立 Department of Pharmacology College of Pharmacy Second Military Medical University. Shanghai 200433PRC

It was reported that anisodamine (654-2)reduced thromboxane synthesis by platelets and lowered the plasma prostaglandin level in endotoxic shock animals when administered in the early phase of shock. However, the exact relationship between arachidonic acid (AA) metabolism and the effects of 654-2 has not been completely understood. We found that 654-2 decreased acetylcholine-and norepinephrine-induced PG release from rabbit iris,

关键词： arachidonic acids, prostaglandins leukotrienes macrophages endotoxin.

Effect of docosahexaenoic acid on interleukin-2 receptor signaling pathway in lipid rafts

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Science China(Life Sciences) 2006年第1期49卷 63-72页

作者： LI Qiurong1, MA Jian1, TAN Li1, WANG Chang2, LI Ning1, LI Yousheng1, XU Guowang2 & LI Jieshou1 1. Institute of General Surgery, General Hospital of Nanjing Command, Nanjing 210002, China 2. National Chromatographic R. & A. Center, Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116011, China Institute of General Surgery General Hospital of Nanjing Command Nanjing 210002 China National Chromatographic R. & A. Center Institute of Chemical Physics Chinese Academy of Sciences Dalian 116011 China

Recent studies have shown that polyunsaturated fatty acids (PUFA) regulated the func-tions of membrane receptors in T cells and suppressed T cell -mediated immune responses. But the molecular mechanisms of immune regulation are not yet elucidated. Lipid rafts are plasma membrane microdomains, in which many receptors localized. The purpose of this study was to investigate the effect of DHA on IL-2R signaling pathway in lipid rafts. We isolated lipid rafts by discontinuous sucrose density gradient ultracentrifugation, and found that DHA could change the composition of lipid rafts and alter the distribution of key molecules of IL-2R signaling pathway, which transferred from lipid rafts to detergent-soluble membrane fractions. These results revealed that DHA treatment increased the proportion of polyunsaturated fatty acids especially n?3 polyunsaturated fatty acids in lipid rafts and changed the lipid environment of membrane microdomains in T cells. Compared with controls, DHA changed the localization of IL-2R, STAT5a and STAT5b in lipid rafts and suppressed the expression of JAK1, JAK3 and tyrosine phosphotyrosine in soluble membrane fractions. Summarily, this study con-cluded the effects of DHA on IL-2R signaling pathway in lipid rafts and explained the regulation of PUFAs in T cell-mediated immune responses.

关键词： polyunsaurated fatty acids, docosahexaenoic acid, IL-2 receptor signaling pathway, lipid raft.

Investigation of side chain liquid crystal polymers bearing cholesterol and bile acid derivatives

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合成化学 2004年第Z1期12卷 79-79页

作者： Stephen Freiberg Franεois Brisse C. Géraldine Bazuin Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7. Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7. Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7.

Cholic acid (or 3a,7a,12a-trihydoxyl-5a-cholan-24-oic acid) and lithocholic acid (or 3a-hydroxyl-5a-cholanic-24-oic acid) are commonly occurring bile acids synthesized from cholesterol in the liver in mammals. They all possess a steroid skeleton containing four rings, three with six carbons and one with five carbons. The transformation of cholesterol to cholic acid results in two major structural changes that affect the steroid skeleton. The first is the hydrogenation of the double bond between C5 and C6 and the second is a conformational flip of ring A from the 5a-position to the 5a-position. In addition, one or more hydroxyl groups are added to the steroid skeleton. Outside of the ring system, C24 is converted from a saturated alkyl to a carboxylic acid *** chain polymers based on cholesterol moiety have been made as reported in the *** bile acids and cholesterol are all in the family of steroid molecules, it is of interest to investigate whether bile acids may also act as mesogenic ***, flexible spacer groups with 10 carbons are introduced between bile acid skeleton and the poymerizable double bonds. The monomers and polymers are compared with cholesterol and dihydrocholesterol monomers and polymers with the same spacers. Dihydrocholesterol is chosen to investigate the influence of the double bond in the formation of LC, given that both cholesterol and dihydrocholesterol have a planar structure but there is no double bond in the latter. These monomers and their corresponding polymers were characterized for their liquid crystalline (LC) properties by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray *** was found that only the compounds bearing the planar cholesterol moieties possess LC phases. It is concluded that the 5a-configuration between the first and second cycles on the steroid skeleton of bile acids does not favor proper alignment of the rigid part of the bile acid moieties.

关键词： bile acids, liquid-crystalline polymers, X-ray