检索结果-南通市图书馆

Fluorescence fluctuation spectroscopy and its artifacts:simulations and tests

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 336-344页

作者： MENG Fanbo 1 , CHEN Bo 1 , LIU Guang 1 , DING Jianying 1 & MA Hui 2.1 1. department of Physics and key {2. of Atomic and Molecular Nano {2.s, Ministry of Educa- tion, tsinghua university, Beijing 100084, china 2. Graduate School at Shenzhen, tsinghua university, Shenzhen 518055, china 1. department of Physics and key {2. of Atomic and Molecular Nano {2.s Ministry of Education Tsinghua University 100084 Beijing China 2. Graduate School at Shenzhen Tsinghua University 518055 Shenzhen China

Fluorescence fluctuation spectroscopy (FFS) technique is capable of monitoring changes in concentration, mass, size and structure of fluorescent-labeled bio-molecules in microscopic volume and is suitable for measuring biological interactions in living cells. FFS data may be affected by many experimental factors in complicated biological systems. Using a Monte Carlo approach, we generate fluorescence fluctuation data for different experimental systems. This approach helps to separate the contributions by different experimental factors in a complicated fluorescence fluctuation spectrum. It also helps to validate new theoretical models and new fitting formulations. We describe the algorithm of the simulation program and tests on its statistical performance. The program is then used successfully to study the effects of several experimental factors on FFS detection.

关键词： fluorescence fluctuation spectroscopy, fluorescence correlation spectroscopy, Monte Carlo simulation.

维普期刊数据库

Zinc up-regulated the expression of the rice metallonthionein gene family and enhanced the zinc tolerance of yeast cells

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第10期17卷 1166-1171页

作者： Xu Yufeng, Zhou Gongke, Li Yiqin and Liu Jinyuan(laboratory of Molecular Biology and Protein science laboratory of the Ministry of Education, department of biological sciences and biotechnology, tsinghua university, Beijing 100084, china) laboratory of Molecular Biology and Protein science laboratory of the Ministry of Education Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

Northern blot and functional complementation assay were employed to analyze the effects of zinc on expression of ten rice metallothionein genes (OsMT-Is) in rice seedlings and the growth of yeast cells transformed with OsMT-Is. Northern blot revealed that in shoots of the rice seedlings treated with different Zn2.concentrations, expression of most members of OsMT-I family was increased, except the type 4 OsMT-Is (OsMT-I-4a, 4b and 4c). In roots, Zn2.significantly increased the transcription of OsMT-I-1b and OsMT-I-2., but reduced the trascription of OsMT-I-1a and OsMT-I-3a. When these ten cDNAs were heterologously expressed in zinc sensitive yeast mutant, all transgenic yeasts showed increased tolerance to Zn2., and zinc accumulation in these yeast cells also increased. These indicated that OsMT-I family members might respond to extra Zn2., and they could enhance Zn2. tolerance of cells by direct binding Zn2..

关键词： rice metallothionein induced expression Zn2. tolerance.

Inhibition of the activating signals in NK92.cells by recombinant GST-sHLAG1α chain

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Cell Research 2004年第2期14卷 155-160页

作者： Ai Yu YAO~(1,2., Hai Yang TANG~1, Yun WANG~1, Mei Fu FENG~(1,*), Rou Li ZHOU~(2.*) ~1State key laboratory of {2. and {2. biotechnology, Institute of Zoology, Chinese Academy of science, Beijing 100080, china ~2.7} of Cell Biology and Medical Genetics, School of Basic Medical sciences, Health science Center, Peking university, Beijing 100083, china. State key laboratory of {2. and {2. biotechnology Institute of Zoology Chinese Academy of Science Beijing 100080 China department of Cell Biology and Medical Genetics School of Basic Medical Sciences Health Science Center Peking University Beijing 100083 China

The soluble HLA-G1 (sHLA-G1) isoform was found to be secreted by trophoblast cells at the matemo-fetal interface, which suggests that it may act as an immunomodulator during pregnancy. In this paper, we reported that GST-sHLA-G1α chain could bind to its receptor ILT-2.on NK92.cells and then the latter recruited Src homology 2.domaincontaining tyrosine phosphatase-1 (SHP-1), which consequently dephosphorylated some important protein tyrosine kinases and blocked the activation of downstream molecules such as MEK and ERK so that the cytotoxicity of natural killer (NK) cells was inhibited. These results indicated that GST-sHLA-G1α chain might be exploited in new immunotherapy strategies aiming at inducing immunotolerance during allograft, xenograft and autoimmune situations. In addition, we found that modification of O-linked β-N-acetylglucosamine (O-GlcNAc) was involved in NK cells’ activating and inhibitory signals. This may provide a novel molecular target for inducing immunotolerance but needs furthe

关键词： NK92 GST-sHLA-G1α chain signal transduction SHP-1 O-G1cNAc.

Expression profiles and transactivation analysis of a novel ethylene-responsive transcription factor gene GhERF5 from cotton

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2009年第5期19卷 563-572页

作者： Longguo Jin, Bo Huang, Hui Li, Jinyuan Liu laboratory of Molecular Biology and MOE laboratory of Protein {2., department of biological {2.s and biotechnology, tsinghua university, Beijing 100084, china [a]laboratory of Molecular Biology and MOE laboratory of Protein {2. Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

Plant AP2.EREBP transcription factors play important roles in plant development and in plant responses to biotic and abiotic stresses. A novel gene for ethylene-responsive element binding protein (EREBP), designated GhERF5, which encodes a protein of 2.5 amino acids, was isolated by RACE-PCR from cotton (Gossypium hirsutum) seedlings. Sequence alignment revealed that GhERF5 contains a typical AP2.ERF domain, and belongs to the B3 subgroup of the ERF subfamily. Particle bombardment assay showed that GhERF5 functions as an in vivo transcription activator in tobacco cells, and it is located in the nuclei of onion epidermis cells. Semi-quantitative RT-PCR revealed that the expression of GhERF5 was highly and rapidly induced when plants were treated with exogenous ethylene, abscisic acid (ABA), salt, cold and drought. Promoter analysis indicated that there are conserved cis-acting elements induced by these stresses in the 50-upstream region of the GhERF5 gene. These results suggest that the GhERF5 gene might play an important role in cotton response to ethylene, ABA and environmental stresses.

关键词： Ethylene-responsive element binding factor (ERF) Abiotic stresses Nuclear localization Transactivation Gossypium hirsutum

The excitation energy transfer between β-Car and Chla molecules in PS Ⅱ core antenna complexes CP43 and CP47

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 2000年第17期45卷 1579-1583页

作者： SHAN Jixiu, WANG Jushuo, LI Liangbi,ZHAO Nanming & KUANG Tingyun1. laboratory of Photosynthesis Basic Research, Institute of Botany, Chinese Academy of sciences, Beijing 100093,{2. 2. department of biological sciences and biotechnology, State key laboratory of biomembrane and membrane biotechnology,{12., Beijing 100084,{2.Correspondence should be addressed to Kuang Tingyun laboratory of Photosynthesis Basic Research Institute of Botany Chinese Academy of Sciences Beijing China department of biological {2.s and biotechnology State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China

The excitation energy transfer efficiency between p-Car and Chla molecules in purified CP43 and CP47 was calculated by comparing absorption and fluorescence excitation after normalization at 550 nm, CP43 had an energy transfer efficiency of 2..1% while the CP47 had an energy transfer efficiency of 62.8%, proving that excitation energy was transferred between p-Car and Chla molecules in CP43 and CP47 at normal conditions. The excitation energy transfer between p-Car and Chla molecules in CP43 and CP47 may occur through the "Dexter" mechanism and the distance between these two kinds of pigments should be less than 1 nm. In addition, the results were also used to discuss the conformational relationship between p-Car and Chla molecules in CP43 and CP47.

关键词： CP43 CP47 β-Car Chla excitation energy transfer.

维普期刊数据库

Cloning and sequence characteristics of the genomic gene of a rice metallothionein

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 2000年第2期45卷 153-156页

作者： YU Lihua, LIU Jinyuan, Masaaki Umeda, Hirofumi Uchimiya & ZHAO Nanming department of biological {2.s and biotechnology, State key laboratory of biomembrane and membrane biotechnology, Beijing 100084, china Institute of Molecular and Cellular Bioscie department of biological {2.s and biotechnology State Key Laboratory of Biomembrane and Membrane Biotechnology Beijing China Institute of Molecular and Cellular Biosciences The University of Tokyo Tokyo Japan

Northern blot analysis showed that a metallothionein gene, ricMT is expressed strongly in the stem of rice with an expression level that could be more than 100-fold stronger than in leaf blades. The results suggest that the 5’ upstream region flanking the coding sequence of the ricMT may contain a fairly strong promoter To elucidatr its regulation and promoter structure, the genomic clones of ricMT were screened out from a rice genomic library and a fragment of about 4084 bp was sequenced. The fragment included a 5’ upstream region of ca. 2.70 bp, a transcription region of ca. 690 bp and a 3’ downstream region of ca. 42. bp. Computer analysis of the sequence homology showed that the 5’ upstream region included a putative TATA box, a putative CAAT box, and a typical metal-responsive element TGCGCGCG. The results will promote further understanding of the mechanisms of gene regulation and metal response of plant metallothionein proteins.

关键词： rice metallothionein genomic gene regulatory sequence.

维普期刊数据库

In vitro and in vivo evaluation of a novel oral insulin formulation

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第10期27卷 1382-1388页

作者： Er-li MA Hong MA Zheng LIU Chang-xue ZHENG Ming-xing DUAN~2.State key laboratory of Bio-{2. and {2.,department of biological sciences and {2.,tsinghua university Beijing 100084,china State key laboratory of Bio-{2. and {2. Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

Aim:To develop a stable self-emulsifying formulation for oral delivery of ***:Caco-2.cell line and diabetic beagles were used as in vitro and in vivomodels to study the absorption mechanism and the hypoglycemic efficacy of *** addition,various physicochemical parameters of the formulationsuch as droplet size,insulin encapsulation efficiency and stability were ***:This formulation enabled changes in barrier properties of Caco-2.onolayers,as referred by transepithelial electrical resistance(TEER)and appar-ent permeability coefficients(Papp)of the paracellular marker ranitidine(2.-foldgreater than control)but not transcellular marker propranolol,suggesting that theopening of tight junctions was *** diabetic beagle dogs,the bioavailabilityof this formulation was up to 15.2. at a dose of 2.5 IU/kg in comparison with thehypoglycemic effect of native insulin(0.5 IU/kg)delivered by ***:This formulation,recently approved by the china StateFood and Drug Administration to enter clinical trials,was stable,degradation-protected and absorption-enhanced,and provided a promising formulation fororal insulin delivery.

关键词： insulin oral delivery Caco-2 diabetic beagles

Effects of disinhibition on spatiotemporal pattern of neuronal first recruitment in neuronal networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2009年第5期19卷 615-621页

作者： Liangbin Pana,b,c,1, Xindong Songa,b,c,1, Guangxin Xiang a,b,c, Jing Zhua,b,c, Jing Cheng a,b,c,d,a Medical Systems Biology Research Center, tsinghua university School of Medicine, Beijing 100084, china b {2. of biological sciences and biotechnology, tsinghua university, Beijing 100084, china c National Engineering Research Center for Beijing Biochip Technology, 18 Life science Parkway, Beijing 102.06, china d State key laboratory of {12. and membrane biotechnology, tsinghua university, Beijing 100084, china [a]Medical Systems Biology Research Center Tsinghua University School of Medicine Beijing 100084 China [b]Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China [c]National Engineering Research Center for Beijing Biochip Technology 18 Life Science Parkway Beijing 102206 China [d]State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing 100084 China

The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulation-evoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network’s native state, the precise first-spike latencies in its dis-inhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways.

关键词： Neuronal recruitment Spatiotemporal pattern Disinhibition Network Multi-electrode array

MEK inhibitor PD98059 acutely inhibits synchronized spontaneous Ca2.oscillations in cultured hippocampal networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第7期27卷 869-876页

作者： Yan-fang RUI~1 Zhao-hui SUN~2.Jia-ping GU~1 Zhong-hua SHENG~1 Xiang-ping HE~1 Zuo-ping XIE~(1,3)1 department of biological {2. and biotechnology,State key laboratory of biomembrane and membrane biotechnology,tsinghua university Beijing 100084,china 2.Institute of Neurological Disorders,Life {2. and Medical department,tsinghua university,Beijing 100084,china departmentofbiological{2.andbiotechnology StateKeyLaboratoryofBiomembraneandMembraneBiotechnologyTsinghuaUniversityBeijing100084China InstituteofNeurologicalDisorders LifeScienceandMedicalDepartment

Aim:To investigate the changes in synchronized spontaneous Ca2.oscillationsinduced by mitogen-activated protein kinase kinase（MEK）inhibitor PD98059 atdifferent concentrations in cultured hippocampal ***:Hippocam-pal neurons in culture for 1-2.weeks were used for this *** activities of these hippocampal neurons were examined by Ca2.imagingusing calcium-sensitive *** inhibitor PD98059（10,30,and 60μmol/L）andSB2.2.74（10 and 60μmol/L）,a negative control for mitogen-activated proteinkinase（MAPK）cascade study,were applied to the cells under the microscopewhile imaging was taking ***:PD98059 at a lower concentration of 10μmol/L had little effect on the Ca2.*** the higher concentration of 30μmol/L,5 min after application of PD98059,the spike frequency was decreased to2..38%±7.40%（mean±SEM,n=16,P2.2.74 atconcentrations of 10 and 60 μmol/L had little inhibition effect on the Ca2.***:These results indicate that PD98059 inhibits synchronized sponta-neous Ca2.oscillation through inhibition of MEK,which hints that the MAPKcascade is required to maintain synchronized spontaneous Ca2.oscillation.

关键词： PD98059 MEK calcium oscillation