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Association of DNA with nuclear matrix in in vitro assembled nuclei induced by rDNA from Tetrahymena shanghaiensis in Xenopus egg extracts

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Cell Research 1997年第1期7卷 107-117页

作者： CHEN YING BO zhang XIU FEN LI ZHONG HE ZHAI(Department of Cell Biology and Genetics, college of life sciences, peking university, beijing 100871) Department of Cell Biology and Genetics College of Life Sciences Peking University Beijing 100871On the occasion of Professor Lu Ji SHI's (L. C. Sze) eightieth birthday we present this paper and extend our sincere greetings to Professor SHI. As we mentioned in our paper in early 1950's it is Professor SHI who first studied the behavior of exogenous homologous desoxyribose nucleoprotein (chromatin) in amphibian eggs. His work later led to the study of nuclear assembly in cell-free system. No words can be said too much to describe Professor SHI's achievements in this field. Since the beginning of our research in this field in 1989 Professor SHI always shows high interests in our work exchanges ideas with us and encourages us. We want to express our deep indebtedness to Professor SHI for his many kindness.Received 31March1997 Revised 7May1997 Accepted 6June1997

The nuclei assembled from exogenous DNA or chromatin in egg extracts resemble their in vivo counterparts in many aspects. However, the distribution pattern of DNA in these nuclei remains unknown. We introduced rDNA from the macronuclei of Tetrabymena into Xenopus cellfree extracts to examine the association of specific DNA sequences with nuclear matrix (NM) in the nuclei assembled in vitro. Our previous works showed the 5'NTS (nontranscription sequences) of the rDNA specifically bind to the NM system in the macronuclei. We show now the rDNA could induce chromatin assembly and nuclear formation in Xenopus cell-free system. When we extracted the NM system and compared the binding affinity of different regions of rDNA with the NM system, we found that the 5'NTS still hold their binding affinity with insoluble structure of the assembled nuclei in the extracts of Xenopus eggs.

关键词： Nuclear assembly nuclear matrix Xenopus egg extracts Tetrahymena rDNA

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Systematic study of the transfer of amino acids across the water/1,2-dichloroethane interface facilitated by dibenzo-18-crown-6

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Science china Chemistry 2004年第1期47卷 24-33页

作者： CHEN Yong, YUAN Yi, zhang Meiqin, LI Fei, SUN Peng, GAO Zhao & SHAO YuanhuaState Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of sciences, Changchun 130022, china college of Chemistry and Molecular Engineering, peking university, beijing 100871, china Lab. of Electroanalytical Chem. Changchun Inst. of Appl. Chem. Chinese Acad. of Sci. Changchun 130022 China Coll. of Chem. and Molecular Eng. Peking Univ. Beijing 100871 China

Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, lie, Phe, Trp, Met, Ala, Gly, Cys, Gin (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (β0), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively. The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attributed to the vicinal effect arising from steric hindrance introduced by their side group and the steric bulk effect by lipophilic stabilization. Moreover, the association constants and the standard rate constants for different amino acids showed good correlations with their hydrophobicity (π), except Gly and Met, which inferred that the selectivity of such heterogeneous complex reaction for different amino acids with DB18C6, was not only affected by discrimination in binding these ions to the crown ether macro-cycle, but also significantly modified by the ion transfer Gibbs energy which was closely related to the structure of the transferred ions, protonated amino acids.

关键词： micro-/nano-pipet, water/1,2-dichloroethane interface, facilitated ion transfer, cyclic voltammetry, amino acid.

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Observation of nuclei reassembled from demembranatedXenopus sperm nuclei and analysis of their laminacomponents

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Cell Research 1994年第2期4卷 163-172页

作者： QU JIAN CHUANMAO zhang ZHONGHE ZHAI.(college of life sciences, beijing university, beijing100871, china) college of life sciences Beijing University Beijing China

A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.

关键词： Nuclear assembly in vitro Xenopus laevis Lamina

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Polycistronic strategy for cyanobacterial expression vector construction: Co-transcription of a human gene and a selective marker gene

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Progress in Natural Science:Materials International 2005年第9期15卷 798-803页

作者： zhang Yukun1, SHI Dingji2, ZHAO Feifei1, YU Meimin1 and RU Binggen1(1. college of life Science, peking university, beijing 100871, china 2. college of Marine sciences & Engineering, Tianjin university of Science & Technology, Tianjin 300450, china) college of life Science Peking University Beijing 100871 China. college of Marine sciences & Engineering Tianjin University of Science & Technology Tianjin 300450 China

A polycistronic expression vector, pKGA-NTF1, was constructed for the cyanobacterium. Within this vector, the spectinomycin/streptomycin resistance gene (aadA) facilitated the selection of transformants when co-transcribed with favorite genes. A natural glnA gene was selected as the platform to introduce the plasmid into a neutral site of the Synechococcus sp. PCC 7002 chromosome. Function of the vector was demonstrated by the insertion of a modified human Trefoil factor 3 gene (NTF1) to upstream of the aadA gene and by the analyses of the transformed strains. Antibiotics resistance assays showed that the dicistronic expression cassette conferred high spectinomycin resistance to both the E. coli cells and the Synechococcus cells. PCR analysis and Western-blot analysis were carried out to confirm the integration and expression of the NTF1 gene, respectively. Through simple molecular manipulations, the artificial polycistronic structure described here can be conveniently used to express other favorable genes or operons in cyanobacteria, and to study the cyanobacterial gene expression as well.

关键词： cyanobacterial transformation human Trefoil factor 3 polycistronic expression Synechococcus sp. PCC 7002 vector construction.

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MAPK signal pathways in the regulation of cell proliferation in mammalian cells

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Cell Research 2002年第1期12卷 9-18页

作者： WEI zhang, Hui Tu LIU The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, college of life sciences, beijing Normal university, beijing 100875, china 1The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education College of Life Sciences Beijing Normal University Beijing 100875 China 1The Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education College of Life Sciences Beijing Normal University Beijing 100875 China

MAPK families play an important role in complex cellular programs like proliferation, differentiation, development, transformation, and apoptosis. At least three MAPI(families have been characterized: extracellular signal-regulated kinase (ERK), Jun kinase (JNK/SAPK) and p38 MAPK. The above effects are fulfilled by regulation of cell cycle engine and other cell proliferation related proteins. In this paper we discussed their functions and cooperation with other signal pathways in regulation of cell proliferation.

关键词： MAPK ER.K JNK/SPAK p38 cell proliferation cross-talk.

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A DSC STUDY OF PHOTOPOLYMERIZATION OF POLYESTERS CONTAINING CONJUGATED DIACETYLENES

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Chinese Journal of Polymer Science 2000年第4期18卷 351-356页

作者： Yao-wen Bai Xiao-fang Chen Dong zhang Xin-hua Wan Qi-feng Zhou Department of Polymer Science and Engineering, college of Chemistry, peking university, beijing 100871, china peking Univ Coll Chem Dept Polymer Sci & Engn Beijing 100871 Peoples R China

The photopolymerization of two kinds of prepolyesters containing conjugated diacetylene (PDA-6 and PDA-12) was investigated using DSC. By measuring the endothermic enthalpy of the prepolymers after different UV-irradiation times, the polymerizations were found to follow the first-order rate law which agreed with the results of other investigators using a different method. The endothermic enthalpy measurements of PDA-6 and PDA-12 before UV-irradiation precluded the possibility that the decrease of endothermic enthalpy was caused by thermal polymerization.

关键词： diacetylene-containing polyesters DSC enthalpy

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SYNTHESIS OF NOVEL LIQUID CRYSTALLINE POLY(METH)ACRYLATES CONTAINING SILOXANE SPACER AND TERPHENYLENE MESOGENIC UNIT

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Chinese Journal of Polymer Science 2000年第2期18卷 101-107页

作者： Zhi-qian Zang Yu-fei Luo Dong zhang Xin-hua Wan Qi-feng Zhou Department of Polymer Science & Engineering, college of Chemistry, peking university, beijing 100871, china peking Univ Coll Chem Dept Polymer Sci & Engn Beijing 100871 Peoples R China

Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4 '-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxane moiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC, DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase. However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results also showed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporated to obtain the highest possible decoupling effect.

关键词： liquid crystalline polymers polyacrylates 4 ''-cyano-p-terphenyl

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Mesozoic thrusts and extensional structures in the Daqingshan orogen, Inner Mongolia, and their temporal and spatial relationship

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Progress in Natural Science:Materials International 2007年第2期17卷 177-186页

作者： QI Guowei, zhang Jinjiang , WANG Xinshe and GUO Lei ( Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, china School of Earth and Space sciences, peking university, beijing 100871, china Institute of Geology, Chinese Academy of Geological sciences, beijing 100037, china) [a]Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education China [b]School of Earth and Space sciences Peking University Beijing China [c]Chinese Academy of Geological sciences Institute of Geology Beijing China

Three large-scale thrusts developed in the Daqingshan orogen, Inner Mongolia, with a northeast-east trending from Louhuashan to Suletu are described in this paper. These northwest-directed thrusts, together with the four tectonic belts (or tectonic sheets) separated by these faults, formed a typical thrusting system. The originally defined Hohhot metamorphic core complex may be a tectonic sheet, making the uppermost tectonic unit of the thrusting system and truncated by the Daqingshan detachment fault on top. The existing tectono-chronological studies showed that the thrusting of this region possibly happened at the same time as the extension along the top detachment fault. This presents that the contraction and extension in Daqingshan orogen were probably simultaneous. The structural pattern of the Daqingshan orogen can be correlated to the Himalayan orogen, and models for simultaneous thrusting and detachment in Himalaya may give a hint for explaining the development of the Daqingshan orogen.

关键词： Daqingshan thrust metamorphic core complex detachment fault contraction-extension transform Himalaya.

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Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M = Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

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Science china Chemistry 2007年第3期50卷 308-317页

作者： zhang Wen, ZHAO Fei, LIU Tao & GAO Song beijing National Laboratory for Molecular sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, college of Chemistry and Molecular Engineering, peking university, beijing 100871, china 1. beijing National Laboratory for Molecular sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

A series of 1D nickel(II)/zinc(II)-lanthanide(III) coordination polymers, [M(μ-L)2Ln(NO3)3]n·solvents (HL = bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1·NiGd), Tb (2·NiTb), Dy (3·NiDy), Ho (4·NiHo), Y (5·NiY); M = Zn, Ln = Gd (6·ZnGd), Tb (7·ZnTb), Dy (8·ZnDy), Ho (9·ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1―9, where weak ferromagnetic interaction is found in 1·NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4·NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.

关键词： nickel lanthanide 3d-4f coordination polymer magnetic property

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SYNTHESIS AND PROPERTIES OF LIQUID CRYSTAL POLYSILOXANES WITH MESOGENIC STILBENE SIDE GROUPS

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Chinese Journal of Polymer Science 2000年第2期18卷 95-99页

作者： Dong zhang Yan-tao Zhu Da-hui Zhao Xin-hua Wan Qi-feng Zhou Department of Polymer Science & Engineering, college of Chemistry, peking university, beijing 100871, china peking Univ Coll Chem Dept Polymer Sci & Engn Beijing 100871 Peoples R China

A variety of mesomorphic side-chain polysiloxanes were synthesized by using hydrosilylation reaction with dicyclopentadienylplatinum(II) (DPPC) as the catalyst. The mesogenic groups are derivatives of stilbene with cyano or nitro tail groups. The products were characterized by DSC, X-ray diffraction and polarizing optical microscopy (POM). All the polymers were found to have relatively low T-g and can form a smectic liquid crystal phase.

关键词： liquid crystal polymer polysiloxane

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