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排序方式: 共有213条查询结果,搜索用时 15 毫秒
191.
Global analysis of protein phosphorylation in yeast 总被引:1,自引:0,他引:1
192.
Veillet C Parker JW Griffin I Marsden B Doressoundiram A Buie M Tholen DJ Connelley M Holman MJ 《Nature》2002,416(6882):711-713
The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects. 相似文献
193.
Golgi biogenesis in Toxoplasma gondii 总被引:7,自引:0,他引:7
Pelletier L Stern CA Pypaert M Sheff D Ngô HM Roper N He CY Hu K Toomre D Coppens I Roos DS Joiner KA Warren G 《Nature》2002,418(6897):548-552
Two models have been put forward to explain the growth of new Golgi during the cell cycle. The first suggests that a new Golgi grows out of the endoplasmic reticulum by de novo synthesis. The second suggests that a pre-existing Golgi is needed for the growth of a new one, that is, the Golgi is an autonomously replicating organelle. To resolve this issue, we have exploited the simplicity of the apicomplexan parasite Toxoplasma gondii, which has only a single Golgi stack. Here we show, by using video fluorescence microscopy and three-dimensional reconstructions of serial thin sections, that the Golgi grows by a process of lateral extension followed by medial fission. Further fission leads to the inheritance by each daughter of a pair of Golgi structures, which then coalesce to re-form a single Golgi. Our results indicate that new Golgi grow by autonomous duplication and raise the possibility that the Golgi is a paired structure that is analogous to centrioles. 相似文献
194.
P. Stern Sabira Čatović N. Filipović 《Cellular and molecular life sciences : CMLS》1973,29(2):144-144
Summary Inhibition of glycine synthesis by aminopterine, an antagonist of pteroilglutaminic acid, causes rigidity of hind limbs in rats. This rigidity can be abolished by the injection of glycine. 相似文献
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196.
Martin J Han C Gordon LA Terry A Prabhakar S She X Xie G Hellsten U Chan YM Altherr M Couronne O Aerts A Bajorek E Black S Blumer H Branscomb E Brown NC Bruno WJ Buckingham JM Callen DF Campbell CS Campbell ML Campbell EW Caoile C Challacombe JF Chasteen LA Chertkov O Chi HC Christensen M Clark LM Cohn JD Denys M Detter JC Dickson M Dimitrijevic-Bussod M Escobar J Fawcett JJ Flowers D Fotopulos D Glavina T Gomez M Gonzales E Goodstein D Goodwin LA Grady DL Grigoriev I Groza M Hammon N Hawkins T 《Nature》2004,432(7020):988-994
197.
Marko PB Lee SC Rice AM Gramling JM Fitzhenry TM McAlister JS Harper GR Moran AL 《Nature》2004,430(6997):309-310
Any fish species that appears to be readily available in the marketplace will create an impression among the public that there is a plentiful supply of that fish in the sea, but this may belie the true state of the fisheries' stock. Here we use molecular genetic analysis to show that some three-quarters of the fish sold in the United States as 'red snapper'--the US Food and Drug Administration's legally designated common name for Lutjanus campechanus--belong to another species. Mislabelling to this extent not only defrauds consumers but could also adversely affect estimates of stock size if it influences the reporting of catch data that are used in fisheries management. 相似文献
198.
In genetic control of disease, does 'race' matter? 总被引:3,自引:0,他引:3
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