Tsinghua Science and Technology

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Volume 10 No. 4
20 April 2005

Analysis of the Cotton E6 Promoter

Aimin Wu, Jinyuan Liu

2005, 10(4): 409-413. doi:10.1016/S1007-0214(05)70091-2

Abstract ( 173 ) ( 263 )

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An E6 gene from sea island cotton (Gossypium barbadense) was expressed specifically in cotton fiber cells to transfer functions to cultivated species for better transgenic engineering. The regulatory activity of the E6 promoter region was then studied by isolating a 614-bp fragment of the 5'-flanking region from upland cotton (Gossypium hirsutum CRI-12) to produce a green fluorescent protein (GFP) reporter construct for analysis of tissue-specific expression in transgenic tobacco seedlings. Fluo...

Inhibition of Alkaline Phosphatase from Pearl Oyster Pinctada fucata by o-Phthalaldehyde: Involvement of Lysine and Histidine Residues at the Active Site

Hongtao Chen, Liping Xie, Zhenyan Yu, Rongqing Zhang

2005, 10(4): 414-420. doi:10.1016/S1007-0214(05)70092-4

Abstract ( 157 ) ( 241 )

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Alkaline phosphatase from Pinctada fucata was inactivated by o-phthalaldehyde (OPA). The inactivation followed pseudo first-order kinetics with a second rate constant of 0.167 (mmol/L)?1?min?1 at pH 7.5 and 25°C. A Tsou's plot analysis showed that inactivation occurred upon formation of one isoindole group. The OPA-modified enzyme lost the ability to bind with the specific affinity column and the presence of substrates or competitive inhibitors protected the enzyme from inactivation. The results...

Expression of an Exo-β-glucanase Gene Is Specifically Related to Lily Pollen Germination and Pollen Tube Growth

Xizhen Liu, Jian Huang, Rongfu Gao, Yiqin Li

2005, 10(4): 421-425. doi:10.1016/S1007-0214(05)70093-6

Abstract ( 153 ) ( 267 )

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The present study is expected to provide better understanding of how exo-β-glucanase acts on the biochemo-rheological property of the cell wall, and thus the regulation mechanism of pollen tube growth. A polymerase chain reaction (PCR)-based strategy and cDNA library screening were used to clone an exo-β-glucanase gene (LP-ExoI) from Lilium longiflorum pollen tubes. The LP-ExoI sequence showed a high level of homology to that of reported plant exo-β-glucan hydrolases. Phylogenetic analysis demon...

Neuron Protective Constituents from Rheum Nanum and Rheum Sublanceolatum

Lan Xiang, Fan Lei, Dongming Xing, Wei Wang, Junhua Zheng

2005, 10(4): 426-429. doi:10.1016/S1007-0214(05)70094-8

Abstract ( 176 ) ( 228 )

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The neuron protective activity of the chemical constituents from Rheum nanum and Rheum sublanceolatum in vitro was investigated using cultured embryonic mouse cortical cells exposed to oxygen-glucose deprivation. The protective effect was quantitatively evaluated by measuring the lactate dehydrogenase release rate. Most of the compounds reduce the lactate dehydrogenase release rate, including emodin, chrysophanol-8-O-β-D-glucopyranoside, 6-hydroxymusizin-8-O-β-D-glucopyranoside, gnetin C, torach...

Internalization of Trichosanthin via Different Endocytic Mechanisms

Fan Zhang, Senfang Sui

2005, 10(4): 430-434. doi:10.1016/S1007-0214(05)70095-X

Abstract ( 204 ) ( 234 )

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Trichosanthin (TCS) is a plant toxin with ribosome-inactivating activity. TCS can be internalized by the host cells and then attacks the ribosomes resulting in cell death. However, the manner for endocytic uptake of TCS is not well understood. The present work investigates the endocytosis pathway of TCS in human choriocarcinoma cells. The different endocytic mechanisms are interfered by potassium depletion, cholesterol-extraction/addition, or treatments of various drugs. The experiments detect t...

Fabrication and Characterization of Chitosan Nerve Conduits with Microtubular Architectures

Qiang Ao, Aijun Wang, Wenling Cao, Chang Zhao, Yandao Gong, Nanming Zhao, Xiufang Zhang

2005, 10(4): 435-438. doi:10.1016/S1007-0214(05)70096-1

Abstract ( 176 ) ( 303 )

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Porous multi-channel chitosan conduits were fabricated using a novel phase-separation technique with an axial temperature gradient. First, porous chitosan tubes were made with a mold that was composed of two concentric polytetrafiuoroethylene tubes. Then 1%-3% (w/v) chitosan solution was injected into the chitosan tube while the two ends of the tube were closed with steel rods. Then the outside of the tube was wrapped with a layer of thermal insulating material to reduce the heat transfer throug...

Behavior of MC3T3-E1 Osteoblast Cultured on Chitosan Modified with Polyvinylpyrrolidone

Jing Xi, Yuan Gao, Lijun Kong, Yandao Gong, Nanming Zhao, Xiufang Zhang

2005, 10(4): 439-444. doi:10.1016/S1007-0214(05)70097-3

Abstract ( 146 ) ( 246 )

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The physical and chemical properties of four kinds of modified chitosan materials made by blending chitosan with polyvinylpyrrolidone (PVP) were investigated. All four of these modified chitosan materials were hydrophilic with water contact angles ranging from 59° to 69°. Fourier transform-infrared spectra of the modified materials showed a new band at 1288 cm?1, implying formation of a surface physical interpenetrating network structure. Enzyme linked immunosorbent assay results indicated that ...

Three-Dimensional Reconstruction of E. coli SecA at Low Resolution

Xijiang Pan, Senfang Sui

2005, 10(4): 445-448. doi:10.1016/S1007-0214(05)70098-5

Abstract ( 122 ) ( 402 )

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SecA is the essential component of the signal-peptide dependent translocation pathway in Escherichia coli (E.coli). The structure and function of SecA must be known to understand the molecular mechanism of preprotein translocation. The high flexibility of SecA causes a dynamic conformational heterogeneity which presents a barrier to the growth of crystals of high diffraction quality. Electron microscopy was used to resolve the macromolecular structure of SecA in solution by negative staining and...

Fiber-Based Chitosan Tubular Scaffolds for Soft Tissue Engineering: Fabrication and in Vitro Evaluation

Aijun Wang, Qiang Ao, Wenling Cao, Chang Zhao, Yandao Gong, Nanming Zhao, Xiufang Zhang

2005, 10(4): 449-453. doi:10.1016/S1007-0214(05)70099-7

Abstract ( 179 ) ( 253 )

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Porous, two-ply tubular chitosan conduits for guided tissue regeneration were fabricated by combining the textile technique (inner layer) with the thermally induced phase separation process (outer layer). A hollow chitosan tube was prepared using an industrial warp knitting process with chitosan yarns. Then, an appropriate diameter mandrel was inserted into the pre-fabricated tube. The tube and the mandrel were dipped into the chitosan solution together, taken out, and freeze-dried. After being ...

Osdof28: A New Member of the DOF Transcription Factor Family from Rice

Feng Chen, Yu Chen, Yixiang Dong, Xin Li, Meng Xu, Chao Zhang, Yongbin Yan, Guiyou Zhang

2005, 10(4): 454-460. doi:10.1016/S1007-0214(05)70100-0

Abstract ( 150 ) ( 241 )

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DOF is a novel family of plant-specific proteins that share a unique and highly conserved DNA binding domain with one CX2CX21CX2C zinc finger motif. In this study, the Osdof28 gene, which codes a characteristic amino acid sequence of the DOF transcription factor family, was screened from rice (Oryza sativa japonica) using a yeast one-hybrid assay. Great amounts of the Osdof28 transcripts were found to accumulate in stems and leaves, with less in the roots, and no detectable transcription found i...

Characteristics of Two Intermediates Trapped in the Unfolding Pathway of Arginine Kinase Induced by Guanidinium Chloride

Xiaogang Guo, Liping Xie, Jicheng Pan, Rongqing Zhang

2005, 10(4): 461-468. doi:10.1016/S1007-0214(05)70101-2

Abstract ( 99 ) ( 257 )

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Equilibrium guanidinium chloride (GdmCl)-induced unfolding of arginine kinase (AK) was investigated by enzymatic activity, intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, circular dichroism (CD) spectrum, and size-exclusion chromatography. The measurements showed that AK unfolded through two equilibrium intermediates: the molten globule state and the partly folded state. Both intermediates have no enzyme activity. The molten globule state exists at 0.4-0.8 mol/L ...

Spatial Heterogeneity and Variability of a Large-Scale Vegetation Community Using a Power-Law Model

Zhiyuan Song, Daming Huang, Masae Shiyomi, Yusheng Wang, Shigeo Takahashi, Hori Yoshimichi, Yasuo Yamamuru, Jun Chen

2005, 10(4): 469-477. doi:10.1016/S1007-0214(05)70102-4

Abstract ( 141 ) ( 307 )

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Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated using a variance power-law model. The data fits the model well with estimates given for the levels of heterogeneity for not only single species but also the community as a whole. The linear regression indicates that the species in the community exhibit a consistently organized spatial ...

OsDREB1 Gene from Rice Enhances Cold Tolerance in Tobacco

Ping Li, Feng Chen, Chao Quan, Guiyou Zhang

2005, 10(4): 478-483. doi:10.1016/S1007-0214(05)70103-6

Abstract ( 164 ) ( 289 )

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The OsDREB1 gene from rice encodes a transcription factor belonging to the DREBP transcription factor subfamily. Many DREBP transcription factors regulate gene expression in response to drought, high-salt, and cold stresses by binding specifically to the dehydration-responsive element (DRE). DRE-binding proteins, such as CBF1, DREB1A, and DREB2A, have been cloned from Arabidopsis thaliana and have been proved to play an important role in stress response of Arabidopsis and several other plants. I...

Interaction of Stathmin-Like 2 Protein with the APP Intracellular Domain

Zhidong Li, Weiwei Wang, Fangfang Zhou, Xia Gao, Gaonong Peng, Huaxi Xu, Ye-Guang Chen

2005, 10(4): 484-488. doi:10.1016/S1007-0214(05)70104-8

Abstract ( 162 ) ( 257 )

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Amyloid precursor protein (APP) plays a critical role in the formation of Alzheimer's disease (AD). The intracellular domain APP (AID) was suggested to cause neurotoxicity in the nucleus. To investigate the functions AID, yeast two-hybrid screening was performed to identify the proteins which interact with AID. The human brain cDNA library was screened using pGBKT7-AID as a bait, and several positive clones were identified. One of them encodes a part of the human stathmin-like 2 protein (STMN2)....

N-Terminal Truncation of TACO Inhibits PMA-Induced U937 Cell Adhesion

Changzhen Liu, Senfang Sui

2005, 10(4): 489-495. doi:10.1016/S1007-0214(05)70105-X

Abstract ( 175 ) ( 245 )

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The effect of TACO1-299, the N-terminal truncation of TACO, on phorbol 12-myristate 13-acetate (PMA)-induced U937 cell adhesion was investigated. Full-length TACO and several truncations were overexpressed in U937 cells. The effects of the expressed proteins on U937 cell adhesion mediated by PMA-induced differentiation were observed by fluorescence microscopy. The results show that the overexpression of TACO1-299 inhibits cell adhesion while overexpressions of the other proteins do not have this...

In vivo Dynamic Studies of Brain Metabolism

Xuechun Luo, Yufeng Jiang, Riqing Zhang

2005, 10(4): 496-498. doi:10.1016/S1007-0214(05)70106-1

Abstract ( 118 ) ( 253 )

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Nuclear magnetic resonance (NMR) can noninvasively monitor intracellular concentrations and kinetic properties of numerous inorganic and organic compounds. A 31P NMR surface coil was used in vivo to dynamically measure phosphocreatine (PCr), adenosine triphosphate (ATP), and intracellular inorganic phosphate (Pi) levels in mouse brain during ischemia-reperfusion to study the damage of cerebral tissues caused by ischemia and effects of herbs on cerebral energy metabolism during ischemia-reperfusi...

Extraction and Purification of Matrix Protein from the Nacre of Pearl Oyster Pinctada fucata

Caiping Ma, Cen Zhang, Yancheng Nie, Liping Xie, Rongqing Zhang

2005, 10(4): 499-503. doi:10.1016/S1007-0214(05)70107-3

Abstract ( 190 ) ( 278 )

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A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters (Pinctada fucata) treated with 10% NaOH solution to investigate the nacre matrix proteins and their effect on the CaCO3 crystal. The protein was characterized by gel exclusion chromatography and reversed-phase high performance liquid chromatography after demineralization by 10% acetic acid. The X-ray diffraction pattern of P14 crystals indicates that P14 plays an important...

Cloning and Characterization of a Homologous Ca2+/Calmodulin-Dependent Protein Kinase PSKH1 from Pearl Oyster Pinctada fucata

Yiping Dai, Liping Xie, Xunhao Xiong, Lei Chen, Weimin Fan, Rongqing Zhang

2005, 10(4): 504-511. doi:10.1016/S1007-0214(05)70108-5

Abstract ( 154 ) ( 237 )

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Many of the effects of Ca2+ signaling are mediated through the Ca2+/calmodulin complex and its acceptors, the Ca2+/calmodulin-dependent protein kinases, including PSKH1. Studies of the proteins involved in the calcium metabolism in oysters will help elucidate the pearl formation mechanism. This paper describes a full-length PSKH1 cDNA isolated from pearl oyster Pinctada fucata. Oyster PSKH1 shares 65% homology with human PSKH1 and 48% similarity with rat CaM kinase I in the amino acid sequence, ...

Monoclonal Antibodies Recognizing HIV-1 gp41 Could Inhibit Env-Mediated Syncytium Formation

Geng Zhang, Yinghua Chen

2005, 10(4): 512-516. doi:10.1016/S1007-0214(05)70109-7

Abstract ( 235 ) ( 278 )

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Some monoclonal antibodies (mAbs) could inhibit infection by HIV-1. In this study, four mAbs against HIV-1 gp41 were prepared in mice. All four mAbs could bind to the recombinant soluble gp41 and recognize the native envelope glycoprotein gp160 expressed on the HIV-Env+ CHO-WT cell in flow cytometry analysis. Interestingly, the results show that all four mAbs purified by affinity chromatography could inhibit HIV-1 Env-mediated membrane fusion (syncytium formation) by 40%-60% at 10 μg/mL, which i...

Molecular Analysis of Dominant Microbial Populations in Heavily and Slightly Polluted Aquifers by a Seaside Landfill

Yangjie Tian, Hong Yang, Daotang Li, Xiujuan Wu

2005, 10(4): 517-522. doi:10.1016/S1007-0214(05)70110-3

Abstract ( 113 ) ( 249 )

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The microbial populations were investigated in two groundwater samples, GW-H and GW-S, which represented heavily and slightly polluted aquifers by a seaside landfill. The concentrations of dissolved redox-relevant species suggested that iron-reduction/sulfate-reduction and denitrification were major redox processes for GW-H and GW-S. The dominant microbial populations were determined using restriction fragment length polymorphism analyses of 16S rRNA gene clone libraries. These microbes were the...