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排序方式: 共有497条查询结果,搜索用时 46 毫秒
121.
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
122.
Wai-Sum Chan 《Journal of forecasting》1993,12(8):677-688
In this paper we consider some of the prominent methods that are available in the literature for the problem of disaggregating annual time-series data to quarterly figures. The procedures are briefly described and illustrated through a real data set. The performances of the methods are compared in a Monte Carlo study. The results indicate that the complicated model-based procedure is usually superior to other non-model-based alternatives in the large sample situations. Based on the simulation results, we make some recommendations regarding the use of these methods. 相似文献
123.
To identify ecotypic variation of L. chinensis, the physiological characteristics and environmental factors were measured and assessed for grey-green and yellow-green ecotypes of L. chinensis grown in the salt-alkalized and aeolian sandy soils. Although both ecotypes presented a similar salt-alkaline tolerance under the experimental conditions, they differed in several aspects. The L. chinensis grown in the aeolian sandy soils had higher water potential and chlorophyll content and lower proline content in their leaves than those grown in the salt-alkalized habitat, and the grey-green ecotype of L. chinensis in both types of soils had higher water potential, chlorophyll and proline contents than the yellow-green ecotype. Besides, grey-green ecotypes had higher salt-alkaline tolerance than the yellow-green ecotype. The stepwise regression analysis showed that soil conductance and pH value were the main ecological factors affecting the physiology of L. chinensis. From the natural distribution of the two ecotypes, we considered that salt-alkaline in the soils is the leading factor in determining ecotypic variation of L. chinensis. The two ecotypes were first named grey-green and yellow-green ecotypes respectively. 相似文献
124.
Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling 总被引:366,自引:0,他引:366
Alizadeh AA Eisen MB Davis RE Ma C Lossos IS Rosenwald A Boldrick JC Sabet H Tran T Yu X Powell JI Yang L Marti GE Moore T Hudson J Lu L Lewis DB Tibshirani R Sherlock G Chan WC Greiner TC Weisenburger DD Armitage JO Warnke R Levy R Wilson W Grever MR Byrd JC Botstein D Brown PO Staudt LM 《Nature》2000,403(6769):503-511
Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically heterogeneous: 40% of patients respond well to current therapy and have prolonged survival, whereas the remainder succumb to the disease. We proposed that this variability in natural history reflects unrecognized molecular heterogeneity in the tumours. Using DNA microarrays, we have conducted a systematic characterization of gene expression in B-cell malignancies. Here we show that there is diversity in gene expression among the tumours of DLBCL patients, apparently reflecting the variation in tumour proliferation rate, host response and differentiation state of the tumour. We identified two molecularly distinct forms of DLBCL which had gene expression patterns indicative of different stages of B-cell differentiation. One type expressed genes characteristic of germinal centre B cells ('germinal centre B-like DLBCL'); the second type expressed genes normally induced during in vitro activation of peripheral blood B cells ('activated B-like DLBCL'). Patients with germinal centre B-like DLBCL had a significantly better overall survival than those with activated B-like DLBCL. The molecular classification of tumours on the basis of gene expression can thus identify previously undetected and clinically significant subtypes of cancer. 相似文献
125.
Joseph W K Chan W B Lee 《厦门大学学报(自然科学版)》2002,(Z1)
Nowadays, new paradigm of enterprise organization i s constantly changing due to the emergence of the global marketplace, the rise of information technology, and the emphasis of the social developments. This re quires a more flexible form of organization that are more adaptable to rapid cha nges in business environment such as autonomous work groups (AWGs) in order to achieve higher productivity and effectiveness. AWGs are work units responsib le for the production of goods and the provision of servi... 相似文献
126.
H. S. Yong K. L. Chan C. Mak S. S. Dhaliwal 《Cellular and molecular life sciences : CMLS》1981,37(2):130-131
Summary Isocitrate dehydrogenase (E.C. 1.1.1.42) gene duplication was demonstrated in the self-pollinated soybean (Glycine max) by means of starch-gel electrophoresis. This finding explains the heterogeneity and/or fixed heterophenotype observed in some soybean cultivars. 相似文献
127.
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129.
A physical map of the mouse genome 总被引:1,自引:0,他引:1
Gregory SG Sekhon M Schein J Zhao S Osoegawa K Scott CE Evans RS Burridge PW Cox TV Fox CA Hutton RD Mullenger IR Phillips KJ Smith J Stalker J Threadgold GJ Birney E Wylie K Chinwalla A Wallis J Hillier L Carter J Gaige T Jaeger S Kremitzki C Layman D Maas J McGrane R Mead K Walker R Jones S Smith M Asano J Bosdet I Chan S Chittaranjan S Chiu R Fjell C Fuhrmann D Girn N Gray C Guin R Hsiao L Krzywinski M Kutsche R Lee SS Mathewson C McLeavy C Messervier S Ness S Pandoh P Prabhu AL Saeedi P 《Nature》2002,418(6899):743-750
A physical map of a genome is an essential guide for navigation, allowing the location of any gene or other landmark in the chromosomal DNA. We have constructed a physical map of the mouse genome that contains 296 contigs of overlapping bacterial clones and 16,992 unique markers. The mouse contigs were aligned to the human genome sequence on the basis of 51,486 homology matches, thus enabling use of the conserved synteny (correspondence between chromosome blocks) of the two genomes to accelerate construction of the mouse map. The map provides a framework for assembly of whole-genome shotgun sequence data, and a tile path of clones for generation of the reference sequence. Definition of the human-mouse alignment at this level of resolution enables identification of a mouse clone that corresponds to almost any position in the human genome. The human sequence may be used to facilitate construction of other mammalian genome maps using the same strategy. 相似文献
130.
Dominant effector genetics in mammalian cells 总被引:6,自引:0,他引:6
Xu X Leo C Jang Y Chan E Padilla D Huang BC Lin T Gururaja T Hitoshi Y Lorens JB Anderson DC Sikic B Luo Y Payan DG Nolan GP 《Nature genetics》2001,27(1):23-29
We have expressed libraries of peptides in mammalian cells to select for trans-dominant effects on intracellular signaling systems. As an example-and to reveal pharmacologically relevant points in pathways that lead to Taxol resistance-we selected for peptide motifs that confer resistance to Taxol-induced cell death. Of several peptides selected, one, termed RGP8.5, was linked to upregulation of expression of the gene ABCB1 (also known as MDR1, for multiple drug resistance) in HeLa cells. Our data indicate that trans-dominant effector peptides can point to potential mechanisms by which signaling systems operate. Such tools may be useful in functional genomic analysis of signaling pathways in mammalian disease processes. 相似文献