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51.
慈竹无性系种群生长发育规律初探 总被引:18,自引:0,他引:18
慈竹(Neosinocalamus affinis)系四川分布面积最大、产量高、用途广的重要经济竹种,对振兴四川经济具有很大的潜在作用。作者引用Harper的构件结构理论,将慈竹无性系作为一个种群进行研究。以慈竹幼竹为研究对象,通过对其生长发 相似文献
52.
M. K. Chandrashekaran G. Marimuthu R. Subbaraj P. Kumarasamy M. S. Ramkumar K. Sripathi 《Journal of biosciences》1991,16(3):97-101
Several bodily functions in humans vary on a 24 h pattern and most of these variations persist with a circadian period ofca 25 h when subjects are studied under conditions of social and temporal isolation. We report in this paper that the estimates
of short time intervals (TE) of 2 h are strongly coupled to the circadian rhythm in sleepwakefulness. There is a linear correlation
between the number of hours humans stay awake (α) and their estimation of 2 h intervals. The coupling of TE to α appears to
obtain only under conditions of physical well-being. 相似文献
53.
The pathogenesis of neuronal dysfunction in the gangliosidoses is poorly understood. Studies of the feline gangliosidoses and in vitro experiments implicate ganglioside inhibition of protein kinase C (PKC) in the pathogenesis of these neurological diseases. Therefore, in the present study, the binding of [3H]phorbol-12, 13 dibutyrate was measured to determine the levels of PKC in cerebral cortex of cats with GM1 gangliosidosis (mutant) and age matched normal siblings. This binding of ([3H]PDB) to cerebral cortex homogenates in both normal and mutant cats was highly specific. The specificity of receptors was ascertained also from displacement studies using nonradioactive phorbol ester analogues to displace [3H]PDB bound to its receptors. In both mutant and normal cat brain, phorbol 12, 13-dibutyrate (PDB), 4--phorbol 12,13-didecanoate (-PDA) and 4--phorbol 12,13-dibenzoate (-PDBz) were highly potent (approximately to same degree) and effective in displacing [3H]PDB. On the other hand, 4- phorbol 12,13-diacetate (-PDA) was a weak displacer and 4--phorbol did not displace the bound [3H]PDB in either normal or mutant brain. Scatchard analysis of the binding data indicated a homogenous single class of binding sites in normal and mutant brain (Normal: Kd=1.42×10–7 M, Bmax=8.40 pmoles/mg protein. Mutant: Kd=1.60×10–7 M, Bmax=10.00 pmoles/mg protein). Sphingosine inhibited the binding to approximately the same extent in normal and mutant cortex. These studies demonstrate the presence of highly specific, homogenous, single type phorbol ester receptors in cerebral cortex of cats with GM1 gangliosidosis which are qualitatively and quantitatively similar to normal cat brain. 相似文献
54.
55.
Residuals for relative risk regression 总被引:2,自引:0,他引:2
56.
57.
Regression analysis based on stratified samples 总被引:1,自引:0,他引:1
58.
Estimation in linear models with censored data 总被引:1,自引:0,他引:1
59.
E. Grist A. D. Woodhead C. Carlson 《In vitro cellular & developmental biology. Plant》1986,22(11):677-680
Summary Several established cell lines from different classes of vertebrates were assayed for the presence of O6-methylguanine acceptor protein. This protein is instrumental in removing adducts from DNA caused by exposure to alkylating
agents. Cultured cells had levels of acceptor protein activity within the range found in fresh tissues from animals in the
same class. We suggest that cells from lower vertebrates are satisfactory in vitro models for studies of this DNA repair function. 相似文献
60.
W. L. C. Vaz D. Hallmann R. M. Clegg A. Gambacorta M. De Rosa 《European biophysics journal : EBJ》1985,12(1):19-24
We have used the fluorescence recovery after photobleaching technique to study the translational diffusion, in L phase multibilayers of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), of fluorescent derivatives of 1-palmitoyl-2-oleoylphosphatidylethanolamine (NBD-POPE) and a membrane-spanning phosphatidylethanolamine (NBD-MSPE). The latter derivative was prepared from a membrane-spanning glycerol-dialkyl-glycerol tetraether lipid isolated from the thermophilic and acidophilic archaebacterium Sulfolobus solfataricus. The translational diffusion was examined between about 15° and 45°C. It is shown that over this temperature range the translational diffusion coefficient for NBD-MSPE is 2/3 that for NBD-POPE which spans only one monolayer of the bilayer. The result is interpreted in terms of existing models for translational diffusion in lipid membranes.Abbreviations D
t
translational diffusion coefficient
- FRAP
fluorescence recovery after photobleaching
- MSPE
a membrane-spanning phosphatidylethanolamine derived from a glycerol-dialkyl-glycerol tetraether lipid isolated from Sulfolobus solfataricus
- NBD
4-nitrobenz-2-oxa-1,3-diazolyl
- PE
phosphatidylethanolamine
- POPC
1-palmitoyl-2-oleoylphosphatidylcholine
- POPE
1-palmitoyl-2-oleoylphosphatidylethanolamine 相似文献