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排序方式: 共有82条查询结果,搜索用时 15 毫秒
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新疆少数民族中学"体育与健康"课程教学现状的调查与研究 总被引:1,自引:0,他引:1
本对新疆南、北疆、东疆地区和乌鲁木齐市的101所民族中学进行实地的调查研究,通过对各民族中学体育教学中大纲、教材、场地器材、汉语授课、男女生分班情况、教师培训、教学计划以及对课程改革的认识等方面的分析.进一步了解新疆各地区民族中学学校体育状况,特别是“体育与健康”课程实施后,各地区民族中学学校体育教学现状以及所面临的问题,旨在加快新疆少数民族中学的体育教学改革和《体育与健康》课程教学研究。为新疆教育主管部门制定实施“体育与健康”课程教学提供决策依据。 相似文献
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Aggressive behavior is pervasive throughout the animal kingdom, and yet very little is known about its molecular underpinnings. To address this problem, we have developed a population-based selection procedure to increase aggression in Drosophila melanogaster. We measured changes in aggressive behavior in the selected subpopulations with a new two-male arena assay. In only ten generations of selection, the aggressive lines became markedly more aggressive than the neutral lines. After 21 generations, the fighting index increased more than 30-fold. Using microarray analysis, we identified genes with differing expression levels in the aggressive and neutral lines as candidates for this strong behavioral selection response. We tested a small set of these genes through mutant analysis and found that one significantly increased fighting frequency. These results suggest that selection for increases in aggression can be used to molecularly dissect this behavior. 相似文献
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Residues of the variable region of the T-cell-receptor beta-chain that interact with S. aureus toxin superantigens 总被引:29,自引:0,他引:29
The alpha beta T-cell antigen receptor (TCR) recognizes antigenic peptides in the context of self major histocompatibility complex (MHC) molecules. The specificity of recognition of MHC plus antigen is generally determined by a combination of the variable elements of alpha- and beta-chains of the TCR. Several types of antigen, however, have been identified that, when bound to MHC molecules, stimulate T cells bearing particular variable-region beta-chain (V beta) elements irrespective of the other variable components of the TCR. These have been termed 'superantigens', and here we are concerned with one type of superantigen, the toxins produced by Staphylococcus aureus. T cells have been found that bear closely related members of the same V beta family but respond differently to S. aureus toxins; in particular, cells bearing the human V beta 13.2 element respond to toxin SEC2, whereas cells bearing human V beta 13.1 do not. We have now defined the residues of the V beta element responsible for this difference, and find that they reside in a region thought to lie on the side of the TCR molecule, away from the conventional antigen/MHC-binding site. The evolutionary conservation of this site may be due to its having an important role in some function of the TCR other than the binding of conventional antigen plus MHC. 相似文献
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Epigenetic inactivation of SFRP genes allows constitutive WNT signaling in colorectal cancer 总被引:29,自引:0,他引:29
Suzuki H Watkins DN Jair KW Schuebel KE Markowitz SD Chen WD Pretlow TP Yang B Akiyama Y Van Engeland M Toyota M Tokino T Hinoda Y Imai K Herman JG Baylin SB 《Nature genetics》2004,36(4):417-422
Aberrant WNT pathway signaling is an early progression event in 90% of colorectal cancers. It occurs through mutations mainly of APC and less often of CTNNB1 (encoding beta-catenin) or AXIN2 (encoding axin-2, also known as conductin). These mutations allow ligand-independent WNT signaling that culminates in abnormal accumulation of free beta-catenin in the nucleus. We previously identified frequent promoter hypermethylation and gene silencing of the genes encoding secreted frizzled-related proteins (SFRPs) in colorectal cancer. SFRPs possess a domain similar to one in the WNT-receptor frizzled proteins and can inhibit WNT receptor binding to downregulate pathway signaling during development. Here we show that restoration of SFRP function in colorectal cancer cells attenuates WNT signaling even in the presence of downstream mutations. We also show that the epigenetic loss of SFRP function occurs early in colorectal cancer progression and may thus provide constitutive WNT signaling that is required to complement downstream mutations in the evolution of colorectal cancer. 相似文献
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Systematic screen for human disease genes in yeast 总被引:19,自引:0,他引:19
Steinmetz LM Scharfe C Deutschbauer AM Mokranjac D Herman ZS Jones T Chu AM Giaever G Prokisch H Oefner PJ Davis RW 《Nature genetics》2002,31(4):400-404
High similarity between yeast and human mitochondria allows functional genomic study of Saccharomyces cerevisiae to be used to identify human genes involved in disease. So far, 102 heritable disorders have been attributed to defects in a quarter of the known nuclear-encoded mitochondrial proteins in humans. Many mitochondrial diseases remain unexplained, however, in part because only 40-60% of the presumed 700-1,000 proteins involved in mitochondrial function and biogenesis have been identified. Here we apply a systematic functional screen using the pre-existing whole-genome pool of yeast deletion mutants to identify mitochondrial proteins. Three million measurements of strain fitness identified 466 genes whose deletions impaired mitochondrial respiration, of which 265 were new. Our approach gave higher selection than other systematic approaches, including fivefold greater selection than gene expression analysis. To apply these advantages to human disorders involving mitochondria, human orthologs were identified and linked to heritable diseases using genomic map positions. 相似文献
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