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Science in China. Series B, Chemistry, life sciences & earth sciences最新文献

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Inhibitory effect of 3'-untranslated region (3'-UTR) of human tissue-plasminogen activator (ht-PA) mRNA on its expression. 人组织纤溶酶原激活物(ht-PA) mRNA 3′-非翻译区(3′-UTR)对其表达的抑制作用。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-10-01
Y Ouyang, P Huang, C Huang
{"title":"Inhibitory effect of 3'-untranslated region (3'-UTR) of human tissue-plasminogen activator (ht-PA) mRNA on its expression.","authors":"Y Ouyang,&nbsp;P Huang,&nbsp;C Huang","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A series of t-PA cDNA mutants containing different parts of 3'-UTR sequences have been constructed. In vitro translation of t-PA transcripts in rabbit reticulocyte lysates and its expression in COS-7 cells show that the 3'-UTR sequence has a very strong inhibitory effect on t-PA translation. The deletion of 3'-UTR results in 3-8-fold increase of t-PA expression. Further study shows that an AU-rich sequence of some 200 nt at 3' end of 3'-UTR is responsible for the translational inhibition. RNA stability experiment reveals that the AU-rich segment leads to a 3-fold decrease of t-PA mRNA stability. The insertion of this segment into the 3'-UTR of luciferase gene results in an obvious inhibition of Luc expression. A model is proposed for the regulation of t-PA expression.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 10","pages":"1253-60"},"PeriodicalIF":0.0,"publicationDate":"1995-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19534765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Three-dimensional structure of CA1 pyramidal cells in rat hippocampus--optical recording of LSM and computer simulation of fractal structure. 大鼠海马CA1锥体细胞的三维结构——LSM的光学记录和分形结构的计算机模拟。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-10-01
C Feng, L Liu, S Liu, H Ning, H Sun, A Guo
{"title":"Three-dimensional structure of CA1 pyramidal cells in rat hippocampus--optical recording of LSM and computer simulation of fractal structure.","authors":"C Feng,&nbsp;L Liu,&nbsp;S Liu,&nbsp;H Ning,&nbsp;H Sun,&nbsp;A Guo","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The optical recording of three-dimensional (3-D) reconstruction of CA1 pyramidal cells was derived from the studies on the CA1 region of the hippocampus in adult male Wistar rats. The recording was produced by the Confocal Laser Scan Microscope (LSM-10). The attemption was to outline the morphological neural network of CA1 pyramidal cells organization, following the trail of axo-dendritic connections in 3-D spatial distributions among neurons. The fractal structure of neurons with their dendritic and axonal trees using fractal algorithm was noticed, and 2-18 simulated cells were obtained using PC-486 computer. The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells. Therefore, the exploitation of an advanced neurohistological research technique combining optical recording of the LSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis for chaosic dynamics of brain.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 10","pages":"1187-94"},"PeriodicalIF":0.0,"publicationDate":"1995-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19535540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Expression of human interleukin-11 cDNA in E. coli. 人白细胞介素-11 cDNA在大肠杆菌中的表达。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-10-01
J Miao, J Wang, S Peng, P Tang, M Zou, J Duan, C Zhao, X Ma
{"title":"Expression of human interleukin-11 cDNA in E. coli.","authors":"J Miao,&nbsp;J Wang,&nbsp;S Peng,&nbsp;P Tang,&nbsp;M Zou,&nbsp;J Duan,&nbsp;C Zhao,&nbsp;X Ma","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A 551-bp hIL-11 gene fragment that includes no nucleotide sequences encoding signal polypeptide and the initial 8 amino acids of the mature protein was cloned into a high-level expression vector pEx31B of E. coli. The authors identified the recombinant plasmid, designated pEx31-IL11, by restriction endonucleases digestion and DNA sequencing. The resulting recombinant plasmids were then used to transform E. coli strain HB101, and expression in the PL promoter system, which is temperature-regulated, was achieved. The expressed fusion protein amounts to 50% of total bacterial proteins. The hIL-11 protein expressed in E. coli was fused to the N-terminal 99 amino acids of the MS2 polymerase to form the inclusion body. These recombinant proteins can be purified to about 80% by extracting inclusion body with urea. One IL-6-dependent cell line 7 TD1 was used for bioassay. The recombinant hIL-11 protein was preliminarily purified and renatured to a specific activity of 10(5)U/mg, even in the presence of an excess of a neutralizing anti-IL-6 antibody.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 10","pages":"1202-9"},"PeriodicalIF":0.0,"publicationDate":"1995-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19535541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Developmental activity variations of DNA polymerase alpha, delta, epsilon in mouse forebrains and spleens. DNA聚合酶α、δ、epsilon在小鼠前脑和脾脏的发育活性变化。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-10-01
R Yang, C Lu
{"title":"Developmental activity variations of DNA polymerase alpha, delta, epsilon in mouse forebrains and spleens.","authors":"R Yang,&nbsp;C Lu","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The levels of DNA polymerase alpha, delta, epsilon were examined in the neonatal mouse forebrains and spleens. The levels of DNA polymerase alpha were determined by the difference of polymerase activity in the absence and the presence of alpha specific inhibitor, BuPdGTP, or its monoclonal antibody. The levels of DNA polymerase delta were determined in H.A fractions after separating it from the other two enzymes. The levels of DNA polymerase epsilon were identified in H.A fractions by the use of alpha-monoclonal antibody or BuPdGTP. Results showed that in the mouse forebrain DNA polymerase alpha, delta, epsilon activities are the highest before birth, decline sharply following birth and are very low on the 8th day and hardly detectable on the 17th day; as for the mouse spleen, however, DNA polymerase alpha, delta, epsilon activities are the lowest at birth, increase rapidly after birth and reach their maxima on the 8th day and then decline gradually but remain in higher levels. These results not only prove that DNA polymerase alpha and delta take part in cell DNA replication but also suggest that DNA polymerase epsilon is involved in DNA replication.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 10","pages":"1237-45"},"PeriodicalIF":0.0,"publicationDate":"1995-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19535543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
C 2 H 5 I的多光子电离质量分辨谱——经 A 态和 D 态的解离电离过程 C 2 H 5 I的多光子电离质量分辨谱——经 A 态和 D 态的解离电离过程
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-10 DOI: 10.1360/ZB1995-25-9-897
丁传凡杨达林赵炜朱起鹤孔繁敖 周游
{"title":"C 2 H 5 I的多光子电离质量分辨谱——经 A 态和 D 态的解离电离过程","authors":"丁传凡杨达林赵炜朱起鹤孔繁敖 周游","doi":"10.1360/ZB1995-25-9-897","DOIUrl":"https://doi.org/10.1360/ZB1995-25-9-897","url":null,"abstract":"用多光子电离飞行时间质谱计系统地研究了C 2 H 5 I分子在278.6～283.5nm和365.8～369.5nm波长区间的激光多光子电离和解离产物以及它们的质量分辨谱,探讨了C 2 H 5 I分子经不同中间共振态 A 态和 D 态的多光子电离和解离过程。","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"20 1","pages":"897-902"},"PeriodicalIF":0.0,"publicationDate":"1995-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82072510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
V/Cu/S异金属簇的合成及(Et 4 N) 2 [V 2 Cu 2 S 4 (C 5 H 10 dtc) 2 (PhS) 2 ]的结构表征 V/Cu/S异金属簇的合成及(Et 4 N) 2 [V 2 Cu 2 S 4 (C 5 H 10 dtc) 2 (PhS) 2 ]的结构表征
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-10 DOI: 10.1360/ZB1995-25-9-909
杨瑜黄梁仁吴达旭康北笙陈昌能邓玉恒卢嘉锡 刘秋田
{"title":"V/Cu/S异金属簇的合成及(Et 4 N) 2 [V 2 Cu 2 S 4 (C 5 H 10 dtc) 2 (PhS) 2 ]的结构表征","authors":"杨瑜黄梁仁吴达旭康北笙陈昌能邓玉恒卢嘉锡 刘秋田","doi":"10.1360/ZB1995-25-9-909","DOIUrl":"https://doi.org/10.1360/ZB1995-25-9-909","url":null,"abstract":"由(NH 4 ) 3 VS 4 ,CuCl,R 2 dtcNa和PhSNa组成的反应体系中,得到V 2 Cu 2 S 4 ,VS 4 Cu 4 及V 3 S 7 三种类型簇合物,讨论了产物形成过程。进行了(Et 4 N) 2 [V 2 Cu 2 S 4 (C 5 H 10 dtc) 2 (PhS) 2 ]的结构表征,确定了它的金属氧化态(Ⅴ(Ⅳ)+Cu(Ⅰ)),研究了它的红外及电子光谱、NMR谱及电化学循环伏安图。","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"17 1","pages":"909-915"},"PeriodicalIF":0.0,"publicationDate":"1995-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90020638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The crystal structure of deshexapeptide (B25-B30) insulin at 0.25 nm resolution. 去六肽(B25-B30)胰岛素在0.25 nm分辨率下的晶体结构。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-01
W Chang, T Jiang, Z Ren, Z Wan, Y Xu, D Liang, S Zhu, Y Zhang
{"title":"The crystal structure of deshexapeptide (B25-B30) insulin at 0.25 nm resolution.","authors":"W Chang,&nbsp;T Jiang,&nbsp;Z Ren,&nbsp;Z Wan,&nbsp;Y Xu,&nbsp;D Liang,&nbsp;S Zhu,&nbsp;Y Zhang","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The determination of deshexapeptide (B25-B30) insulin (DHI) was divided into two steps. At the first step, the rough structure model of DHI molecule was determined by using the molecular replacement method associated with the molecular close-packing method at 0.30 nm resolution based on the reflection data collected on four-cycle diffractometer. At the second step, the DHI model was adjusted and refined at 0.25 nm resolution based on the data collected on Area Detector. 40 water molecules were determined during the refinement, the final R-factor is 0.185 with R.M.S. deviation of 0.002 nm for bond lengths and 1.9 degrees for bond angles. The differences in conformation and function of DHI with other insulin analogues were compared and discussed.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 9","pages":"1094-100"},"PeriodicalIF":0.0,"publicationDate":"1995-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19534768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Biological activity assays of cell-free reassembled nuclei--injecting cell-free reassembled nuclei into unfertilized eggs can induce the eggs to cleave and reconstitute asters, and the injected nuclei undergo cell cycle changes. 无细胞重组核的生物活性测定——将无细胞重组核注射到未受精卵中，可诱导卵分裂和重组，注射后的细胞核发生细胞周期变化。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-01
C Zhang, J Qu, J Liang, Z Zhai
{"title":"Biological activity assays of cell-free reassembled nuclei--injecting cell-free reassembled nuclei into unfertilized eggs can induce the eggs to cleave and reconstitute asters, and the injected nuclei undergo cell cycle changes.","authors":"C Zhang,&nbsp;J Qu,&nbsp;J Liang,&nbsp;Z Zhai","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Nucleus may reassemble spontaneously in cell-free mixture of HeLa metaphase chromosomes, Xenopus egg extracts and ATP-regenerating system, and the nucleus shows some biological activities. It is found that, after being injected into unfertilized mature eggs, the cell-free reassembled nuclei can cause the eggs to cleave and reconstitute asters in their cytoplasm, and the injected nuclei undergo changes in response to cell cycle regulators stored in the eggs, and that reinjecting cytostatic factors (CSF) into the eggs can stabilize the eggs in mitotic phase, cause the nuclei disassembly and chromatin condensation to chromosomes.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 9","pages":"1075-83"},"PeriodicalIF":0.0,"publicationDate":"1995-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19534766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
High expression of synthetic human interferon-gamma cDNA in E. coli. 合成人γ干扰素cDNA在大肠杆菌中的高表达。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-01
Z Wang, D Yang, Q Wang, B Li, Z Lü, J Yu, H Zheng, P Fan, J Tang, M Qian
{"title":"High expression of synthetic human interferon-gamma cDNA in E. coli.","authors":"Z Wang,&nbsp;D Yang,&nbsp;Q Wang,&nbsp;B Li,&nbsp;Z Lü,&nbsp;J Yu,&nbsp;H Zheng,&nbsp;P Fan,&nbsp;J Tang,&nbsp;M Qian","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Human interferon-gamma (IFN-gamma) cDNA was synthesized, and it makes the usage of favorable codons in E. coli. The authors got 9 different expression plasmids which contain the synthetic IFN-gamma-cDNA and have different spaces between SD sequence and ATG. The free energies G0f298 in the formation of stable secondary structure in the translation initiation region (TIR) are different in various expression plasmids. One of them, pLY4-gamma 5, can highly yield INF-gamma which will be about 60%-80% of the total bacterial proteins, such a high expression was hardly noted in literature. The reasons of high expression in this work are optimal spaces between SD and ATC, favorable delta G0f298, favourable condons usage for E. coli.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 9","pages":"1084-93"},"PeriodicalIF":0.0,"publicationDate":"1995-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19534767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
ESR study on calcineurin. 钙调磷酸酶的ESR研究。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-09-01
Q Wei, F Xiao, J Lu, J Zhou
{"title":"ESR study on calcineurin.","authors":"Q Wei,&nbsp;F Xiao,&nbsp;J Lu,&nbsp;J Zhou","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>X-band electron spin resonance spectroscopy was used to investigate the binding of Mn2+ to the apo-forms of calcineurin and its A and B subunits. The results indicated the presence of 2 Mn2+ binding sites of different affinities (20 mumol/L and 60 mumol/L) in the calcineurin A subunit and 4 Mn2+ binding sites in the calcineurin subunit B, 2 high affinity and 2 low affinity binding sites with Kd's of 4 mumol/L and 90 mumol/L, respectively. Interestingly and quite surprisingly, Mn2+ binding to the holoenzyme was characterized by only 2 binding sites with Kd's of 7 mumol/L and 33 mumol/L. However, in the presence of calmodulin about 10 Mn2+ sites were detected, and the Mn2+ calmodulin-calcineurin complex exhibited enzymatic activity. These results, based on direct spectral measurements of the metal ligand, demostrate that Mn2+ binds to both free subunits of calcineurin in a manner distinct from binding to the holoenzyme. Also, the data suggest that conformational changes occur upon heterodimer formation and association of the holoenzyme with the regulatory protein calmodulin.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 9","pages":"1117-22"},"PeriodicalIF":0.0,"publicationDate":"1995-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19534769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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