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HongMA Xing-GuoHAN Editors-in-chief 《植物学报(英文版)》2005,47(1):1-1
As we begin 2005, plant biologists have great opportunities to unlock the secrets of plant life. The realization of the importance of biodiversity and global ecology has promoted increasing efforts in understanding individual, population, and community plant biology. At the same time, the advances in plant molecular biology, genetics, 相似文献
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The deduction of biogeographic process from the study of its history is complicated by the fact that history is a singular thing. This singularity allows no estimation of the degree of determinism surrounding the realization of biogeographic processes, and consequently we know almost nothing about the generality of such deductions. Here we discuss a new approach, called 'experimental biogeography', that exploits computers to model faunal build-up repeatedly against a fixed vicariant background over ecological and evolutionary time scales. This new approach enables a biogeographer to be omniscient - to know both vicariant history and actual phylogeny. Moreover, history can be replayed repeatedly to accumulate a sample of multiple phylogenies and to estimate probability density functions for biogeographic variables. Roles of stochastic, historical and ecological processes in adaptive radiations can also be assessed. Experimental biogeography allows examination of the reliability of various methods of recovering historical patterns. 相似文献
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Based on the results of research conducted over last two decades, lysophospholipids (LPLs) were observed to be not only structural components of cellular membranes but also biologically active molecules influencing a broad variety of processes such as carcinogenesis, neurogenesis, immunity, vascular development or regulation of metabolic diseases. With a growing interest in the involvement of extracellular lysophospholipids in both normal physiology and pathology, it has become evident that those small molecules may have therapeutic potential. While lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) have been studied in detail, other LPLs such as lysophosphatidylglycerol (LPG), lysophosphatidylserine (LPS), lysophosphatidylinositol (LPI), lysophosphatidylethanolamine (LPE) or even lysophosphatidylcholine (LPC) have not been elucidated to such a high degree. Although information concerning the latter LPLs is sparse as compared to LPA and S1P, within the last couple of years much progress has been made. Recently published data suggest that these compounds may regulate fundamental cellular activities by modulating multiple molecular targets, e.g. by binding to specific receptors and/or altering the structure and fluidity of lipid rafts. Therefore, the present review is devoted to novel bioactive glycerol-based lysophospholipids and recent findings concerning their functions and possible signaling pathways regulating physiological and pathological processes. 相似文献
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This report describes a method for quantifying -endotoxin contents in spray-dried preparations ofBacillus thuringiensis strain GC-91. -Endotoxin is solubilized in the pro-toxin form and separated from other soluble compounds by ion exchange chromatography. The method does not discriminate between the different -endotoxins produced by strain GC-91. It is suitable for quality control, since -endotoxin concentrations found in different preparations correlate inversely with the LC 50 in bioassays on artificial diet against freshly hatched larvae ofSpodoptera littoralis. A typical batch of spray-dried material contains 1.22%±0.08% -endotoxin. The method is most accurate with preparations containing 0.5 to 2.0% toxin, for which triplicate estimations give standard errors close to±0.2%. 相似文献
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In a recent article M.G. Sacco and co-workers described the establishment of immortalized untransformed transgenic hepatocyte (MMH-GH) cell lines, obtained from a cross between the AT/cytoMet and Hsp70/hGH transgenic mice. This strategy proved to be successful because the MMH-GH showed stability in culture and sensitivity to chemical exposure. Based on these results, the MMH-GH cell lines could prove to be a valid alternative cell-based assay for use in toxicological studies. 相似文献