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51.
Neutrophil extracellular traps kill bacteria 总被引:5,自引:0,他引:5
Brinkmann V Reichard U Goosmann C Fauler B Uhlemann Y Weiss DS Weinrauch Y Zychlinsky A 《Science (New York, N.Y.)》2004,303(5663):1532-1535
Neutrophils engulf and kill bacteria when their antimicrobial granules fuse with the phagosome. Here, we describe that, upon activation, neutrophils release granule proteins and chromatin that together form extracellular fibers that bind Gram-positive and -negative bacteria. These neutrophil extracellular traps (NETs) degrade virulence factors and kill bacteria. NETs are abundant in vivo in experimental dysentery and spontaneous human appendicitis, two examples of acute inflammation. NETs appear to be a form of innate response that binds microorganisms, prevents them from spreading, and ensures a high local concentration of antimicrobial agents to degrade virulence factors and kill bacteria. 相似文献
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Adult human brain contains cholestanol and two series of cholesterol precursors having 30, 29, 28, and 27 carbon atoms; one has an unsaturated steroid nucleus, and the other is unsaturated in both nucleus and side chain. The ability of preparations of brain to incorporate a specific precursor into cholesterol, as well as into these sterol metabolites in vitro, indicates that cholesterol synthesis continues long after brain maturation ceases. 相似文献
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Weiss G 《Science (New York, N.Y.)》2002,296(5574):1781-1782
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Dopamine: mediator of brain polysome disaggregation after L-dopa 总被引:4,自引:0,他引:4
The disaggregation of brain polysomes which is produced by giving large doses of (L)-dopa to rats is not reproduced by administering its metabolite, 3-O-methyldopa, by giving D-dopa, which also depletes the brain of S-adenosylmethionine but is not converted to catecholamines, or by giving the L-dopa after a decarboxylase inhibitor. Polysome disaggregation is potentiated by the prior administration of a monoamine oxidase inhibitor, indicating that formation of a catecholamine is an obligatory requirement. These observations suggest that the mechanism by which L-dopa disaggregates brain polysomes involves its conversion to dopamine within the majority of brain cells. 相似文献
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In 1971 Hafele and Keating carried portable atomic clocks east and then west around the world and verified the Sagnac effect, a special relativity effect attributable to the earth's rotation. In the study reported here observations of the effect were made by using electromagnetic signals instead of portable clocks to make clock comparisons. Global Positioning System satellites transmit signals that can be viewed simultaneously from remote stations on the earth; thus an around-the-world Sagnac experiment can be performed with electromagnetic signals. The effect is larger than that occurring when portable clocks are used. The average error over a 3-month experiment was only 5 nanoseconds. 相似文献
60.
Schierbaum KD Weiss T van Veizen EU Engbersen JF Reinhoudt DN Göpel W 《Science (New York, N.Y.)》1994,265(5177):1413-1415
It is shown by angle-resolved x-ray photoelectron spectroscopy that cavitands derived from resorcin[4]arenes provided with four dialkylsulfide chains form stable monolayers on gold surfaces that are well organized by self-assembly. The cavitand headgroups at the surface of the resorcin[4]arene monolayer act as molecular recognition sites for small organic molecules with remarkable selectivity for perchloroethylene (C(2)Cl(4)). Comparative thermal desorption experiments indicate binding sites with high interaction energies of C(2)Cl(4) at the surface of the resorcin[4]arene monolayers. Fast and reversible "host-guest" interactions were found by the monitoring of extremely small mass changes (in the nanogram range) with a quartz microbalance oscillator provided with gold electrodes coated by resorcin[4]arene monolayers. 相似文献