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排序方式: 共有288条查询结果,搜索用时 15 毫秒
111.
L. Yin C. M. Chung R. Huo H. Liu C. Zhou W. Xu H. Zhu J. Zhang Q. Shi H. Y. C. Wong J. Chen Y. Lu Y. Bi C. Zhao Y. Du M. Ma Y. Cai W. Y. Chen K. L. Fok L. L. Tsang K. Li Y. Ni Y. W. Chung Z. Zhou J. Sha H. C. Chan 《Cellular and molecular life sciences : CMLS》2009,66(5):900-908
The acrosome reaction has long been thought to be induced by the zona pellucida. Here we report the identification and function
of a novel human sperm glycosylphosphatidylinositol (GPI)-anchored membrane protein, NYD-SP8. The release of the protein during
sperm-egg interaction and its binding to the cumulus, the first layer of egg investment, elicits cross-talk between the gametes
and produces calcium dependant release of progesterone, which lead to the acrosome reaction. An in vivo mouse model of NYD-SP8 immunization is also established showing a reduced fertility rate. Thus, contrary to accepted dogma,
our study demonstrates for the first time that, prior to reaching the zona pellucida, sperm may release a surface protein
that acts on the cumulus cells leading to the acrosome reaction, which may be important for determining the outcome of fertilization.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 11 August 2008; received after revision 18 December 2008; accepted 22 December 2008 相似文献
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Zusammenfassung Nachweis adrenerger Synapsen an Zellkörpern der duodenalen submukösen Ganglien von Ratten nach 6-Hydroxydopamin-Behandlung.
Part of this work was done while I was on sabbatical leave in the Department of Anatomy, Monash University, in 1972, and I thank ProfessorG. C. Schofield for his kindness and encouragement during my stay there. Mr.H. L. Chan rendered invaluable technical assistance. 相似文献
Part of this work was done while I was on sabbatical leave in the Department of Anatomy, Monash University, in 1972, and I thank ProfessorG. C. Schofield for his kindness and encouragement during my stay there. Mr.H. L. Chan rendered invaluable technical assistance. 相似文献
115.
The dramatic progress in the understanding of the dynamics of biomolecules has been largely fuelled by computer simulations based on the law of classical mechanics. However in some respects biomolecules are at the borders of the domain of applicability of classical mechanics. The role of quantum mechanical effects in biomolecular structure and function is therefore worth investigating. Here we present preliminary results from a quantum simulation of a protein and contrast them with results from full classical simulations. The most significant differences are found in motions of high frequency, such as bond stretching or the torsional oscillation of groups that bear hydrogen atoms. The amplitudes of such motions are significantly increased by the penetration of atoms into classically forbidden regions. These differences will directly influence the rates of such processes as proton and electron transfer. 相似文献
116.
I. H. Hall R. A. Izydore R. Simlot O. T. Wong 《Cellular and molecular life sciences : CMLS》1992,48(4):383-386
1,2,4-Triazolidine-3,5-diones and the 3,5-isoxazolidinedione were, observed to be, potent inhibitors of rat lens aldose reductase activity. In vivo in streptozotocin-diabetic rats, selected agents at 20 mg/kg/day, orally for 21 days reduced significantly the sorbitol levels of rbc, lens and sciatic nerves, suggesting that these derivatives may have some usefulness to treat clinical complications of diabetes mellitus. 相似文献
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鳜暴发流行病病毒性病原研究 总被引:25,自引:2,他引:23
患病鳜肾脏、脾脏、肝脏、心脏、鳃中发现二十面体病毒粒子,肾脏和脾脏是其感染主要器官.成熟病毒粒子直径150nm,核心球状,直径105nm.受感染细胞肿大,直径为正常细胞3~4倍,细胞核萎缩,为正常细胞核直径1/3.病毒粒子部分纯化后,经腹腔人工感染,第7天开始死亡,10d内死亡率为100%,表现与池塘养殖状态相同症状,并在人工感染鳜肾和脾中电镜观察发现大量相同病毒粒子,命名为传染性脾肾坏死病毒(infectiousspleenandkidneynecrosisvirus,ISKNV). 相似文献
119.
M. Anthony Wong 《Journal of Classification》1984,1(1):255-270
A random sample of sizeN is divided intok clusters that minimize the within clusters sum of squares locally. Some large sample properties of this k-means clustering method (ask approaches withN) are obtained. In one dimension, it is established that the sample k-means clusters are such that the within-cluster sums of squares are asymptotically equal, and that the sizes of the cluster intervals are inversely proportional to the one-third power of the underlying density at the midpoints of the intervals. The difficulty involved in generalizing the results to the multivariate case is mentioned.This research was supported in part by the National Science Foundation under Grant MCS75-08374. The author would like to thank John Hartigan and David Pollard for helpful discussions and comments. 相似文献
120.
Summary Nicotine, in concentrations of 5 and 25 g/ml drinking water, given ad libitum for 10 days, dose-dependently increased lesion formation and worsened ethanol-induced ulceration in rat stomachs. Daily fluid intake and b.wt gain were not adversely affected by nicotine pretreatment.The authors are grateful to Mr C.T. Luk for his skilled technical assistance. 相似文献