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51.
以猪血清为材料,通过磷酸乙醇胺—琼脂糖亲和层析,Sepharose 4B柱层析和Sephacryl—S300凝胶过滤,获得了猪C—反应蛋白的结晶。猪C—反应蛋白可与肺炎球菌壁C多糖发生特异的沉淀反应,这种结合是依赖钙离子的。EDTA和一些磷脂代谢产物如磷酸胆碱,磷酸乙醇胺等,能抑制猪C—反应蛋白与C多糖的结合。在SDS—聚丙烯酰胺凝胶电泳及梯度聚丙烯酰胺凝胶电泳中,猪C—反应蛋白表现出与人C—反应蛋白相同的行为,亚基是一条分子量为23.5kD的肽链,全分子的表观分子量为150kD。猪C—反应蛋白与兔抗人C—反应的蛋白的抗血清能发生免疫交叉反应。 相似文献
52.
The ventilatory response of the newborn to CO2 was studied using a rebreathing method that minimized changes in arterial PO2 during the test. The aim was to study the variability of the ventilatory response to CO2 and take this into account to assess the relative magnitude of the response to CO2 during rapid-eye-movement (REM) sleep and quiet sleep (QS). Five full-term babies aged 4-6 days were given 5% CO2 in air to rebreathe for 1.5-3 min. O2 was added to the rebreathing circuit to maintain arterial O2 saturation and transcutaneous PO2 (Ptco2) at prerebreathing levels. Tests were repeated four to five times in REM sleep and QS. Mean Ptco2 levels varied between individuals but were similar during REM sleep and QS tests for each subject. The mean coefficient of variability of the ventilatory response was 35% (range 15-77%) during QS and 120% (range 32-220%) during REM sleep. PtcO2 fluctuations during tests [6.0 +/- 3.0 (SD) Torr, range 1-13 Torr] were not correlated with ventilatory response. Overall the ventilatory response was significantly lower in REM sleep than in QS (12.2 +/- 3.0 vs. 38.7 +/- 3.0 ml.min-1.Torr-1.kg-1, P less than 0.001; 2-way analysis of variance) due to a small (nonsignificant) fall in the tidal volume response and a significant fall in breathing rate. In 12 REM sleep tests there was no significant ventilatory response; mean inspiratory flow increased significantly during 8 of these 12 tests. We conclude that there is a significant decrease in the ventilatory response of the newborn to CO2 rebreathing during REM sleep compared with QS. 相似文献
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江苏省常熟市地处长江南岸阳澄湖畔,临近大中城市,距上海100km,离苏州、无锡、南通不足50km,历史上为苏南重点商品粮基地之一。因地理位置、地形、地貌及大气环流等因素所决定,常熟属北亚热带南部湿润地区,年平均气温15.5℃,年日照时数2202.9小时,年雨量1038.4mm。全市境内湖泊、河流纵横交错连结成网,有水域1.75×10~4ha,大小河流4477条。全境总面积1142.2km~2,北部较高,海拔3.11m左右,向南缓缓降低,最低地区海拔0.61m。 相似文献
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用P.inui广西株经蚊传和血传接种4只猴子,让大劣按蚊每6小时吸血感染1次,连续数周,以蚊胃感染情况判断配子体的感染性。结果发现:本虫株配子体发育成熟的需72n+K小时;配子体生理寿命约12小时;配子体的感染性具有每隔2天,在后半夜出现高峰的周期性变化;血中大环状体百分比高峰与蚊媒感染高峰一致。 相似文献
57.
Epidermal growth factor receptor (EGFR) gene expression and growth stimulation of EGF on human hepatoma cells of cell lines BEL-7404 and SMMC-7721 were studied. 125I-EGF binding assay was used to measure the binding characteristics and the amounts of EGFR on these cells. The binding time course and the binding competition assay showed that the binding of 125I-EGF to 7404 cells was saturable and specific. Scatchard analysis of EGF binding curve indicated that 7404 and 7721 cells expressed approximately 1.1 x 10(5) and 0.7 x 10(5) EGFRs per cell with binding affinity (Kd) 2.1 nM and 1.8 nM respectively. Northern hybridization and immunoblotting analysis showed the EGFR gene expression products in 7404 and 7721 cells were 5.6 Kb mRNA and 170 Kilo-dalton glycoprotein. Anchorage-dependent growth of 7404 and 7721 cells was stimulated in the presence of nanogram quantities of EGF in medium containing 10% calf serum or 0.5% calf serum. The factors in serum appeared to act synergitically in stimulating of cell proliferation. EGF also stimulated the anchorage-independent growth of 7404 and 7721 cells in soft agar. The results suggest that EGFR is actively expressed in human hepatoma 7404 and 7721 cells and EGF may be one of the mitogens needed for the growth of hepatoma cells. 相似文献
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Adipocyte lipid-binding protein (ALBP) is the adipocyte member of an intracellular hydrophobic ligand-binding protein family. ALBP is phosphorylated by the insulin receptor kinase upon insulin stimulation. The crystal structure of recombinant murine ALBP has been determined and refined to 2.5 A. The final R factor for the model is 0.18 with good canonical properties. Crystalline ALBP has a conformation which is essentially identical to that of intestinal fatty acid binding protein and myelin P2 protein. Although the crystal structure is of the apo- form, a cavity resembling that in other family members is present. It contains a number of bound and implied unbound water molecules and shows no large obvious portal to the external milieu. The cavity of ALBP, which by homology is the ligand-binding site, is formed by both polar and hydrophobic residues among which is tyrosine 19. Y19 is phosphorylated by the insulin receptor kinase as described in the accompanying paper [Buelt, M. K., Xu, Z., Banaszak, L. J., & Bernlohr, D. A. (1992) Biochemistry (following paper in this issue)]. By comparing ALBP with the earlier structural results on intestinal fatty acid binding protein, it is now possible to delineate conserved amino acids which help form the binding site in this family. 相似文献
60.
兴安落叶松结实规律与长短枝习性的关系 总被引:1,自引:0,他引:1
1987年5月,大兴安岭林区发生的特大森林火灾,实属世界罕见,火灾面积达1.0×10~6ha 多。大量的火烧迹地亟待更新、无论是人工更新还是人工促进天然更新,其中关键的问题之一是种子的来源,在大兴安岭地区,兴 相似文献