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We have developed a novel approach to the analysis of antigenic (allotypic and idiotypic) determinants on intact immunoglobulin molecules. Immune complexes composed of IgG in combination with anti-idiotype or anti-allotype antibody were "visualized" by transmission electron microscopy. Individual Fab fragments of anti-idiotype or anti-allotype antibody, when bound to the IgG, altered the "Y" configuration in a reproducible and interpretable manner. Anti-idiotype antibody (either as Fab or IgG) bound to the terminus of the presumed V region of the IgG molecule, thus extending the apparent length of the Fab arms. Analysis of a rabbit VH framework allotype (a1) revealed that the determinant(s) is (are) located on the lateral portion of the V region of IgG. Binding of the anti-a1 Fab fragments was always at approximately right angles to the axis of the Fab arms of IgG. Fab antibody to the rabbit kappa light chain (b4) allotype bound to the lateral portion of the terminal half of the IgG Fab arms. This technique should be of value in localizing less well defined immunoglobulin determinants.  相似文献   

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Immunoelectron microscopy of IgG molecules in human mature placenta has shown that IgG bound to microvillar surfaces and the inner wall of endocytotic vesicles of syncytiotrophoblasts. The endocytotic vesicles, containing both bound and unbound IgG molecules, tended to fuse with each other or with other cellular organelles, particularly with lysosomes. The phagolysosomes were more abundant in the basal regions of the cells. Apparently some IgG molecules were not digested by lysosomal enzymes. Vesicles with residual IgG were found to fuse with the basal and basolateral cell membrane and to discharge their contents into the extracellular space by exocytosis. It is suggested that IgG molecules were transported through the trophoblastic basement membrane and the interstitial space by diffusion to the endothelial basement membrane. The IgG molecules then migrated into the fetal vascular lumen via endothelial gaps and interendothelial spaces.  相似文献   

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Penicillinase was localized in log-phase cells of Bacillus licheniformis 749/C by labeling with ferritin-anti-penicillinase immunoglobulin G conjugate. Mildly fixed homogenized cells, isolated subcellular fractions, and frozen thin sections were labeled. The label was distributed in discrete patches in the cell envelope. The patches extended from the inside part of the membrane to the outside part of the wall. The inside part of the membrane was labeled more extensively than the outside part. The cytoplasm also bound some ferritin-immunoglobulin G conjugate. Immunoelectrophoresis and biochemical assay of cytosol material suggest that the cytoplasmic antigenic sites are a protease-sensitive form of penicillinase.  相似文献   

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Immunoelectron microscopic localization of calmodulin in corn root cells   总被引:4,自引:0,他引:4  
Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized in the nucleus, cytoplasm, mitochondria as well as in the cell wall, In the meristematic cells, calmodulin was distinctly localized on the plasma membrane, cytoplasmic face of rough endoplasmic rcticulum and polyribosomes. Characteristically, calmodulin was present in the amyloplasts of root-cap cells. The widespread distribution of calmodulin may reflect its plciotropic functions in plant cellular activities.  相似文献   

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Ubiquitin, a 76 amino acid protein, is covalently attached to abnormal and short-lived proteins, thus marking them for ATP-dependent proteolysis in eukaryotic cells. Free (unconjugated) ubiquitin was localized in hepatoma cells using affinity purified anti-ubiquitin antibodies and colloidal gold immunoelectron microscopy. The anti-ubiquitin antibodies recognize only unconjugated ubiquitin. Ubiquitin is found within the cytoplasm, nucleus, the microvilli, autophagic vacuoles and lysosomes.  相似文献   

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A peroxidase-anti-peroxidase (PAP) method using polyclonal anti-PR antibodies was used to localize progesterone receptor (PR) electron microscopically in the chick oviduct. The immunoreaction precipitate indicating PR was localized inside the nuclei of epithelial, glandular and stromal cells. In the estrogen withdrawn oviduct cytoplasmic immunoreaction precipitate was not seen. Inside the nucleus unoccupied PR was localized mainly like the heterochromatin. As visualized by the PAP technique, the localization of PR was not systematically changed after progesterone administration. In conclusion, we suggest that progesterone receptor in the chick oviduct is an intranuclear protein.  相似文献   

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Abstract Nitrogenase (Fe-protein) was localized in the free-living cyanobacterium Anabaena cylindrica and in the cyanobionts of Cycas revoluta and Peltigera aphthosa , using colloidal gold as an immunocytochemical marker. The Fe-protein was found to be evenly distributed throughout the heterocyst cytoplasma in A. cylindrica and in both the cyanobionts, including multiple heterocysts of the C. revoluta cyanobiont. No label was observed in the vegetative cells of free-living A. cylindrica or of the cyanobionts, although the cyanobionts apparently live under microaerobic conditions.  相似文献   

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Using protein A-colloidal gold immunoelectron microscopy and monospecific antibodies to the weak base primaquine, we have delineated acidic intracellular compartments in the human hepatoma cell line, HepG2. Primaquine specifically accumulated within endocytotic compartments (including CURL vesicles, multivesicular bodies and lysosomes). In addition, the Golgi cisternae were positive. However, the CURL tubules, which contain recycling asialoglycoprotein receptor, did not accumulate primaquine. Thus, there may be a gradient of acidification within the endocytotic pathway.  相似文献   

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Summary The subcellular distribution of carbonic anhydrase III in rat soleus and vastus lateralis muscles was studied using an immunogold technique. The enzyme protein was found to be distributed diffusely in the cytoplasm of skeletal muscle cells. Red skeletal muscle (mainly type I fibers) revealed very strong immunogold staining whereas in white muscle (mainly type II fibers) gold particles were almost completely absent. No immunoreaction was observed in mitochondria or in other intracellular organelles.  相似文献   

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The recent production of a series of monoclonal estrophilin (estrogen receptor) antibodies recognizing estrogen receptor derived from a wide variety of animals and target tissues permits the development of immunoelectron microscopic techniques for identifying estrogen receptor. We have determined suitable conditions for the ultrastructural localization of estrogen receptor in tissue sections. Localization of receptor was observed in the euchromatin, but not in the marginated heterochromatin or nucleoli of epithelial and stromal nuclei of human endometrium. Competition studies indicate that only estrogen receptor specifically inhibits nuclear staining. The absence of any specific cytoplasmic localization at the electron-microscopic level is consistent with earlier light-microscopic observations and suggests that the majority of the cellular pool of estrophilin exists in the nucleus of hormone-responsive cells.  相似文献   

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The monoclonal antibody M6-7, which recognizes both native and denatured immunopurified M6a antigen, was used in the present immunocytochemical study to localize its corresponding antigen in young rat brain. Strong labelling was observed in the cerebellar molecular layer, which corresponds to heavily stained axon terminals originating from granule cells. The immunodeposit, as observed by electron microscopy, is present only on the cytoplasmic side of the presynaptic membrane and on the membrane of synaptic vesicles. In contrast, the Purkinje cells and their processes are unstained. Stained synapses are also found, although less frequently, in several other cerebral areas. The pattern of staining at these synapses is similar to that observed in the cerebellar molecular layer. It is hypothesized, on the basis of its restricted distribution in certain neuronal endings and its high homology with myelin proteolipids, that the M6a antigen revealed by the M6-7 antibody is probably involved in a specific biological function in these structures.  相似文献   

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Myofibrillogenesis in developing cardiac cells of the Syrian hamster from early embryonic stages through newborn was studied by electron microscopy, immunofluorescence microscopy and immunoelectron microscopy. alpha-Actinin and actin were localized at light and electron microscopic levels in embryonic heart cells which had been fixed in a periodate-lysine-paraformaldehyde or a glutaraldehyde-formaldehyde mixture, and embedded in Lowicryl K4M. Indirect staining methods were used for immunofluorescence staining of thick sections and immunoferritin staining of thin sections. The earliest evidence of myofibrillogenesis in embryonic myocardial cells was the presence of many randomly arranged thin (6 nm) filaments and a few scattered thick filaments (15 nm) near the plasma membrane. alpha-Actinin was detected in a semi-continuous, diffuse layer in some portions of the cell just beneath the plasma membrane in association with the filamentous collections. Later in development, alpha-actinin coalesced into Z-plaques at the membrane as the filaments arranged into parallel arrays. Actin was localized in the thin filaments as expected. In later stages of development, alpha-actinin was observed at the Z-lines and intercalated discs of the mature myofibrils while actin was localized at both the I-band and Z-line. Our results suggest that myofibrillogenesis is initiated at the plasma membrane and that Z-plaques are precursors of myofibrillar Z-bands and may serve as organizing centers for myofibrillogenesis in developing cardiomyocytes.  相似文献   

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S Yokota  T Oda 《Histochemistry》1983,78(4):417-424
Localization of serine: pyruvate aminotransferase [EC 2.6.1.51]; SPT in rat eosinophile leukocytes was investigated by protein A-gold technique. Thin sections of rat intestine were incubated with anti-SPT, followed by protein A-gold complex. Labelling with gold particles was seen on the specific granules of eosinophile leukocytes, in which 78% of the gold particles were localized on their paracrystalline cores and 22% on matrix, indicating that the main intragranular sites of SPT are the core. Other cell organelles such as nucleus and mitochondria were not labelled specifically. Quantitative analysis of labelling density in the subcellular compartments also confirmed that SPT is present exclusively in the specific granules.  相似文献   

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