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51.
Summary Two new defensive steroids (lucibufagins6 and7) and a fluorescent pterin (8) have been isolated and characterized from the fireflyPhotinus pyralis.Acknowledgment. We are grateful to the Fonds National Suisse de la Recherche Scientifique (bourse de relève to M.G.). Partial support of this work by the NIH (grants No. AI 12020 and AI 02908), the NSF (grant No. PCM-77-25807), and the American Heart Association is acknowledged with pleasure. Paper No. 66 of the series Defense Mechanism of Arthropods. 相似文献
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The identification and an efficient synthesis of 6-methoxy-2-benzoxazolinone (MBOA), an insect antifeedant inZea mays is reported. 相似文献
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X. Wang C. A. Lessman D. B. Taylor T. K. Gartner 《Cellular and molecular life sciences : CMLS》1995,51(11):1097-1102
Gastrulation is characterized by dramatic cell migration which is thought to require the interaction of cell adhesion molecules with extracellular molecules. We have tested two novel peptides, a fibronectin peptide and a fibronectin receptor peptide, for their effects on gastrulation of the leopard frogRana pipiens. The fibronectin peptide DRVPHSRNSIT corresponds to residues 1373–1383 of the cell-binding domain of fibronectin; the receptor peptide DLYYLMDL corresponds to residues 124–131 of 1 subunit of a variety of integrins including 51. Either of these peptides significantly inhibited gastrulation after being microinjected into mid-blastulae. These results indicate that these sequences may correspond to the ligand/receptor interaction sites of fibronectin and its receptor(s). 相似文献
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Both in vivo and in vitro models have certain disadvantages for the study of the chronic hepatotoxicity of drugs. The aim of this work was to evaluate a new approach based on an in vivo/in vitro model. After chronic in vivo treatment of rats with Vincamine and Vindeburnol (an eburnamenine derivative which exhibits hepatotoxic properties in man) liver cells were isolated, and functional and metabolic disorders (metabolic utilization of fructose and protein biosynthesis) were studied to determine injury. The results showed no modification of blood parameters, but a direct relationship between the dose of Vindeburnol administered in vivo and the metabolic disorders observed in vitro, evidencing the high sensitivity and reliability of this model. 相似文献
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甲型H1N1流感病毒流行株基因组进化分析 总被引:9,自引:0,他引:9
2009年4月, 北美地区出现甲型H1N1流感疫情, 并且疫情快速扩散至欧亚非三大洲, 风险等级上升至5级. 截止至5月13日, 甲型H1N1流感病毒已扩散至33个国家和地区, 实验室确认病例5728例, 死亡61人. 从NCBI的IRV和GISAID的EpiFluDB数据库下载甲型H1N1流感病毒序列425条, 进行序列比对与进化分析. 分析结果显示: (ⅰ) 当前流行的甲型H1N1流感病毒是一个三重排A型流感病毒: HA, NA, MP, NP和NS来源于猪流感病毒; PB2和PA来源于禽流感病毒; PB1来源于人流感病毒. (ⅱ) 猪流感病毒的来源可细分为: HA, NP和NS来源于H1N1亚型经典猪流感毒株; NA和MP来源于H1N1亚型禽源猪流感毒株. (ⅲ) 甲型H1N1流感病毒在流行扩散过程中没有显著变异, 同时病毒基因组没有发生重排. 本文除了分析美国代表毒株A/California/04/2009(H1N1)外, 还以墨西哥代表毒株A/Mexico/4486/2009(H1N1)为主进行了同源性和进化分析, 地理范围相对较大, 分析结果更具科学性. 相似文献
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A lot of attention has been paid to action learning in the last three decades or so and the success of such programmes has also been widely publicized. But why have these programmes been so effective in helping organizations cope with change? Many writers state that the success of such programmes is due to the fact that they link learning to actions. Yet others claim that action learning programmes succeed because they involve employee empowerment and provide a much greater learning curve. In this paper the authors hold that action learning programmes succeed because they are partly systemic and can be made even more effective if they are fully designed and implemented systemically. The essential features of a systemic method include the ability to help organizations deal with organic, cultural and power complexity. The conclusion that action learning programmes can succeed if they are fully designed and implemented systemically is reached by comparing the essential features of a systemic method with that of an action learning programme. The authors make use of a case study to support their conclusion. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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