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The 3' terminal sequence of chicken ovalbumin messenger RNA and its comparison with other messenger RNA molecules. 总被引:5,自引:0,他引:5
C C Cheng G G Brownlee N H Carey M T Doel S Gillam M Smith 《Journal of molecular biology》1976,107(4):527-547
The subcellular distribution of actin in embryonic chick fibroblasts and brain was examined biochemically. Several gentle extraction procedures, which did not cause the breakdown of muscle filamentous actin, caused the release of large amounts of “cytoplasmic actin” in a monomeric form. This did not behave as a precursor or degradation product of filamentous actin in pulse label experiments and failed to form filaments under the same conditions as muscle actin. However, when it was purified and concentrated it was able to form aggregates which were very similar to paracrystals of muscle filamentous actin. These results suggest that cytoplasmic actin is at a higher concentration than muscle actin before it will polymerize, and that in the cell much of it is either monomeric or in a labile state. 相似文献
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Global stability of a predator-prey system 总被引:2,自引:0,他引:2
In this paper we derive a result to ensure the global stability of a predator-prey system. The method used is quite general and may have applications to other situations.Works were partially supported by the National Science Council of the Republic of China 相似文献
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本文对我院91 ̄94年收治的35例,由淋球菌引起的急性淋菌性盆腔腹膜炎的发病情况进行了分析。资料显示:淋菌性盆腔腹膜炎发病以中青年妇女为多。性乱及不洁的性生活是诱发本病的原因。无先兆症状使本病无特异性,但脓性白带、尿路刺激症状、宫颈与阴道壁充血以及腹膜刺激症有助于本病的诊断。确诊则依据涂片染色检菌及细菌培养。大剂量的青霉素或第三代头孢菌素的应用,可使本病早日治愈。 相似文献
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Heparin modulation of laminin polymerization 总被引:4,自引:0,他引:4
Previously, it has been shown that laminin will self-assemble by a two-step calcium-dependent process using end-domain interactions (Yurchenco, P. D., Tsi-library, E. C., Charonis, A. S., and Furthmayr, H. (1985) J. Biol. Chem. 260, 7636-7644). We now find that heparin, at low concentrations, modifies this polymerization by driving the equilibrium further toward aggregation, by producing a denser polymer, and by inducing aggregation in the absence of calcium. This effect on self-assembly is specific in that it is observed with heparin but not with several heparan sulfates or other glycosaminoglycans: it correlates with affinity and depends on the degree of polysaccharide sulfation. Heparin binds to laminin in a calcium-dependent manner with a single class of interaction (KD = 118 +/- 18 nM) and with a binding capacity of one heparin for two laminins. We find the long arm globule (E3) is the only laminin domain which exhibits substantial heparin binding: heparin binds E3 with an affinity (KD = 94 +/- 12 nM) and calcium dependence similar to that for intact laminin. These data strongly suggest that heparin modifies laminin assembly by binding to pairs of long arm globular domains. As a result the polymer may be stabilized at domain E3 and laminin interdomain interactions induced or modified. We further postulate that heparins may act in vivo as specific regulators of the structure and functions of basement membranes by both altering the laminin matrix and by displacing weakly binding heparan sulfates. 相似文献
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