共查询到20条相似文献,搜索用时 15 毫秒
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Korochkin LI 《Ontogenez》2002,33(5):361-365
The studies of A.A. Neyfakh on morphogenetic nuclear activity are considered in the light of experimental embryology data. 相似文献
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Richter J 《BMJ (Clinical research ed.)》2000,321(7266):957; author reply 958-957; author reply 959
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In this study, we have systematically compared the uranyl photocleavage of a range of bent A-tracts and nonbent TA-tracts as well as interrupted A-tracts. We demonstrate that uranyl photocleavage of A-tracts and TA-tracts is almost identical, indicating a very similar minor groove conformation. Furthermore, a 10 base pair A-tract is divided into two independent tracts by an intervening TA or GC step. Uranyl probing also clearly distinguishes the bent A4T4 and the nonbent T4A4 sequences as adopting different structures, and our interpretation of the data is consistent with a structure for the bent A4T4 sequence that resembles a continuous A-tract, whereas the nonbent T4A4 sequences are closer to two independent and opposite A-tracts that cancel each other in terms of macroscopic bending. Finally, we also note that even single TA and TAT steps are highly sensitive to uranyl photocleavage and propose that in addition to average minor groove width, uranyl also senses DNA helix flexibility/deformability. Thus, the structural difference of TA-tracts and A-tracts may to a large extent reflect a difference in flexibility, and DNA curvature may consequently require a rigid narrow minor groove conformation that creates distinct A-tract-B-DNA junctions as the predominant cause of the bending. 相似文献
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Karen B. Helle 《BBA》1971
1. Chromogranin A has been isolated from the washed membrane fraction of highly purified chromaffin granules after solubilization in Triton X-100. A hydrated molecular weight of 2.9·105 has been obtained for chromogranin AM which in its electrophoretic mobility and molecular volume appears very similar to chromogranin AI of the water-soluble fraction. 相似文献
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cDNAs of barley α-amylase andA. niger glucoamylase were cloned in oneE. coli-yeast shuttle plasmid resulting in the construction of expression secretion vector pMAG15. pMAG15 was transformed intoS. cerevisiae GRF18 by protoplast transformation. The barley α-amylase andA. niger glucoamylase were efficiently expressed under the control of promoter and terminator of yeast PGK gene and their own signal sequence. Over 99% of the enzyme activity expressed was secreted to the medium. The recombinant yeast strain, S.cerevisiae GRF18 (pMAG15), hydrolyzes 99% of the starch in YPS medium containing 15% starch in 47 h. The glucose produced can be used for the production of ethanol. 相似文献
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Zizhong Tang Shan Liu Haijun Jing Rong Sun Moyang Liu Hui Chen Qi Wu Xueyi Han 《Molecular biology reports》2014,41(11):7567-7573
A β-glucosidase gene (bgl) from Aspergillus oryzae GIF-10 was cloned, sequenced and expressed. Its full-length DNA sequence was 2,903 bp and included three introns. The full-length cDNA sequence contained an open reading frame of 2,586 nucleotides, encoding 862 amino acids with a potential secretion signal. The A. oryzae GIF-10 bgl was functionally expressed in Pichia pastoris. After 7-day induction, protein yield reached 321 mg/mL. Using salicin as the substrate, the specific activity of the purified enzyme reached 215 U/mg. The purified recombinant β-glucosidase was a 110-kDa glycoprotein with optimum catalytic activity at pH 5.0 and 50 °C. The enzyme was stable between 20 and 60 °C, and retained 65 % of its activity after being held at 60 °C for 30 min. The recombinant β-glucosidase was relatively stable in a broad range of pHs, from 4.0 to 6.5. It showed broad specific activity, hydrolyzing a range of (1-4)-β-diglycosides and (1-4)-α-diglycosides, and Mn2+ stimulated its activity significantly. 相似文献