共查询到17条相似文献,搜索用时 93 毫秒
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本文首次把ABC法应用于受体流动性测量中的膜表面受体荧光标记,利用FRAP(Fluorescence Recovery After Photobleaching)技术实现了细胞内吞过程中膜受体流动性变化的测量.实验用Con A—Biotin和Avidin—FITC(ABC法)标记巨噬细胞ConA受体,测量ConA刺激不同时间细胞膜表面受体的荧光强度、扩散系数和荧光恢复率的变化.结果显示ABC标记法适合于测量细胞内吞过程中膜表面受体的流动性变化,且具有较高的灵敏度高;巨噬细胞受ConA刺激后,膜表面ConA受体的扩散系数和荧光恢复率较静息状态时明显降低. 相似文献
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本文用FRAP(fluorescencerecoveryafterphotobleaching)技术,测量了静息状态和刀豆素A刺激不同时间后巨噬细胞膜磷脂、ConA受体扩散系数和荧光恢复率的变化。结果显示ConA刺激后膜磷脂和ConA受体的扩散系数和荧光恢复率均较静息状态的巨噬细胞明显降低,磷脂流动性的变化与ConA受体流动性的变化呈正相关。提示受体介导内吞导致的膜磷脂流动性的降低,可能是由于配体与细胞膜上受体结合形成配体-受体复合体,增加了受体的负荷,使受体的流动性降低,进而使膜磷脂的流动性降低。巨噬细胞内吞过程中膜磷脂和ConA受体流动性的降低,可能还与ConA刺激后巨噬细胞胞浆pH值有关。 相似文献
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本文首次实现了细胞内吞过程中膜受体流动性的测量。实验选择巨噬细胞膜和伴刀豆凝集素A(ConA),分别用Con A-Biotin Avi-din-FITC(ABC法)和Con A-FITC(直接法)两种方法标记巨噬细胞膜Con A受体,比较了这两种方法标记的巨噬细胞Con A受体的荧光强度;利用FRAP(Fluorescence RecoveryAfter Rhotobleaching)技术,分别用两种标记方法测量了巨噬细胞Con A受体的流动性。结果显示Con A-Biotin Avidin-FITC标记的巨噬细胞受体的平均荧光强度比用Con A-FITC标记的平均荧光强度高大约3倍;直接标记法应用于细胞内吞过程中受体流动性的测量在方法学上存在着很大的缺陷,ABC标记法适合于测量细胞内吞过程中膜表面受体的流动性的变化,且灵敏度高、误差小;ABC方法标记受体的测量结果显示,Con A刺激后巨噬细胞膜表面Con A受体的扩散系数和荧光恢复率与静息状态相比呈下降趋势。 相似文献
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小鼠Lewis肺癌组织经氯仿甲醇去除脂类,用木瓜蛋白酶消化,再经Sephadex柱层析分离得到总糖肽。它有明显地抑制小鼠Lewis肺癌细胞,S180肉瘤细胞及人巨细胞肺癌细胞与层粘连蛋白(Laminin,LN)基质粘着的作用;对层粘连蛋白受体(LN-R)与其配体的识别及结合也具有同样明显的阻断效应。糖肽的上述作用均具有剂量依赖性。进一步经ConA-Sepharose CL-4B亲和层析将总糖肽分为三个部分。与ConA不结合的糖肽部分对Lewis肺癌细胞与LN基质的粘着也具有剂量性抑制作用。 相似文献
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配体与膜受体结合可启动细胞信息传递通路,激活细胞并产生生物学效应。应用共聚焦激光扫描显微术,流式细胞分光光度计,生物活性测量等技术,研究MA与巨噬细胞膜受体结合后,膜下肌动蛋白丝构筑和含量随时间变化,以及细胞热能量改变。结果是ConA结合巨噬细胞膜受体后,膜下肌动蛋白多聚化加快,构筑成细胞内F-actin立体空间网络,F-actin含量增加具有时间相关性,细胞热能量增加。巨噬细胞内这些变化提示ConA通过膜受体诱导膜下肌动蛋白多聚化和构筑过程有信息传递和激活细胞等重要作用。 相似文献
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Mobility modulation by local concanavalin A binding. Selectivity toward different membrane proteins 总被引:3,自引:0,他引:3
Y I Henis 《The Journal of biological chemistry》1984,259(3):1515-1519
We have employed fluorescence photobleaching recovery to demonstrate selective immobilization of lymphocyte membrane proteins by localized concanavalin A (ConA) binding to the cell surface. Localized ConA binding was achieved by the binding of ConA coupled to paraformaldehyde-fixed platelets to mouse spleen lymphocytes. The effect of the localized cross-linking of ConA receptors on the lateral mobility of specific membrane proteins at regions distal to the ConA platelets was investigated. The diffusion of surface immunoglobulins and ConA receptors was inhibited above a threshold coverage (12%) of the upper lymphocyte surface by ConA platelets. In contrast, no effect was observed on the diffusion and aggregation of mouse histocompatibility antigens (H-2Kk) labeled with a fluorescent monoclonal antibody. Since the ConA modulation was shown to propagate through the cytoskeleton, these results indicate specificity in the interactions of membrane proteins with the cytoskeleton. This specificity enables a selective response of different membrane proteins to the ConA anchorage modulation. 相似文献
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配体与膜受体结合可启动细胞信息传递通路,激活细胞并产生生物学效应。应用共聚焦激光扫描显微术,流式细胞分光光度计,生物活性测量等技术,研究MA与巨噬细胞膜受体结合后,膜下肌动蛋白丝构筑和含量随时间变化,以及细胞热能量改变。结果是ConA结合巨噬细胞膜受体后,膜下肌动蛋白多聚化加快,构筑成细胞内F-actin立体空间网络,F-actin含量增加具有时间相关性,细胞热能量增加。巨噬细胞内这些变化提示ConA通过膜受体诱导膜下肌动蛋白多聚化和构筑过程有信息传递和激活细胞等重要作用。 相似文献
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Vagn Leick Thorkild C. Bg-Hansen Sren T. Christensen Stephen J. Kaufman 《Experimental Biology Online》1997,1(5):1-12
The relationship between concanavalin A (ConA) receptors and the chemosensory behaviour of the ciliated protozoan Tetrahymena thermophila was studied using the peptide chemoattractants proteose peptone and fibroblast growth factor. Studies on the chemosensory behaviour in semisolid methylcellulose showed that 50 μg/ml ConA selectively inhibited the persistent element of swimming behaviour by reducing time runs of cells responding to proteose peptone from 12.2±4.5 min to 0.8±0.3 min. Methyl-alpha-D-mannoside, but not methyl-alpha-D-galactoside, abolished the inhibitory effect of ConA, suggesting that mannoside-containing ConA receptors are involved in maintaining a persistent swimming behaviour. Control experiments, carried out in liquids where persistent swimming is less important for cellular behaviour, showed that ConA did not affect proteose-peptone-induced chemoattraction under these conditions as measured by a two-phase assay for chemoattraction. Also, no inhibitory effect of ConA could be found on swimming rates when individual velocities of ConA-treated cells were determined. When tested in liquid chemoattraction assays, ConA was found to be a weak but significant chemoattractant. Studies of the cellular location of ConA receptors on the plasma membrane of starved cells showed an unequal distribution. A preferential clustering of receptors at the anterior end of the cell was observed when determined at high concentrations (100 μg/ml) of fluorescent ConA. Methyl-alpha-D-mannoside but not methyl-alpha-D-galactoside abolished the fluorescent ConA labelling, indicating a preferential clustering of these mannoside-containing receptors at the anterior part of the plasma membrane and cilia. At lower concentrations (25 μg/ml), FITC-ConA produced more general labelling of the entire cell membrane. The results suggest that ConA receptors are necessary for the persistent element of swimming and that binding of ConA to its receptors interferes with processes related to signal transduction rather than by limiting the free movement of cilia required for locomotion. The gradient of receptors seen at high FITC-ConA concentrations may be important for a putative spatial chemosensory mechanism, i.e. chemotaxis.Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users. 相似文献
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Recently,the effect of ligand receptor interaction on the membrane structure of liposomes has been studied extensively,However,little is known about how it exists on biological membranes,In this paper,the effect of Concanavalin A(ConA) receptorinteratcion on the structure of cell membranes was studied by Circular DIchrosim(CD) and 31P Nuclear Magnetic Resonance(NMR).CD results of both the purified macrophage membranes and human erythrocyte hgosts(EG) showed that the conformation of membrane proteins changed after ConA binding.For further research,31P-NMR was used to detect the orgainzation of phosp[holipid molecules on macrophage membranes.After ConA binding,the tendercy to form non bilayer structure increased with the amount of ConA.The changes of 31P-NMR spectra of living macrophages might be partly due to the above stated reason too.In addition,ConA-receptor interaction also induced similar results of 31P-NMR spectra in EG.In contrast,wheat germ agglutinin (WGA),another kind of lectin,rarely showed the same influence. 相似文献
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Stimulation of polymorphonuclear leukocytes (PMN) by tetravalent concanavalin A (alpha-ConA) induces membrane depolarization preceding the onset of superoxide anion (O2-) production. Both divalent and monovalent ConA analogues were studied to evaluate the role of valence. Monovalent ConA (m-ConA) was inactive in stimulating O2- production and divalent derivatives were less active than native alpha-ConA. Similarly, membrane depolarization was dependent on the valency of ConA. m-ConA did not induce a marked change in membrane potential, whereas sustained depolarization occurred with multivalent ConA. The formation of multiple linked interactions between surface receptors may be an important early event in the activation of PMN by ConA. 相似文献