scholarly journals A novel methodology for double protein A-gold immunolabeling utilizing the monovalent fragment of protein A.

1992 ◽  
Vol 40 (3) ◽  
pp. 435-441 ◽  
Author(s):  
J R Thorpe
Keyword(s):  
Electron Microscopy ◽  
Binding Sites ◽  
Secretory Granules ◽  
Protein A ◽  
Model System ◽  
Normal Serum ◽  
Gold Complex ◽  
Thin Sections ◽  
Igg Binding ◽  
Gold Probe

A method for sequential protein A-gold immunolabeling is described whereby the binding of second gold probe to the first antibody-protein A-gold complex is reduced to acceptably minimal levels. Immunolabeling of thin sections of embedded pituitary tissue was used as a model system. After an initial immunolabeling for prolactin, sections were incubated in normal serum (rabbit) followed by a monovalent fragment of protein A. These latter two incubations reduced artifactual second gold probe label over prolactin-labeled secretory granules to minimal levels (much less than 1 particle per granule) when sections were subsequently immunolabeled with normal serum. The combination of normal serum and protein A fragment incubations saturates IgG and protein A binding sites on the first antibody-gold probe complex. The latter is thereafter unable to bind further IgG (and thus gold probe) because of the monovalent nature of the protein A fragment. It is suggested that this methodology may be extended to multiple immunolabeling procedures for electron microscopy. In addition, when used before single labeling this method may be an effective way to minimize nonspecific IgG binding in cases where the tissue or antibody under study may be a problem.

Electron spectroscopic imaging for high-resolution immunocytochemistry: use of boronated protein A.

1989 ◽  
Vol 37 (5) ◽  
pp. 573-580 ◽  
Author(s):  
M Bendayan ◽  
R F Barth ◽  
D Gingras ◽  
I Londoño ◽  
P T Robinson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
High Resolution ◽  
Binding Sites ◽  
Secretory Granules ◽  
Protein A ◽  
Spectroscopic Imaging ◽  
Acinar Cells ◽  
Indirect Detection ◽  
Electron Spectroscopic Imaging ◽  
Thin Sections

In the present study we adapted electron spectroscopic imaging (ESI) for high-resolution immunocytochemistry. To accomplish this, we applied boronated protein A (B-pA) for indirect detection of specific antigenic sites using pre-embedding and post-embedding protocols. Isolated acinar cells were exposed to wheat germ agglutinin (WGA) and anti-WGA, followed by B-pA, to reveal WGA binding sites at the level of the plasma membrane. The cells were then embedded in Epon and unstained ultra-thin sections were examined by electron microscopy using the ESI mode. For post-embedding, ultra-thin sections of glutaraldehyde-fixed, Lowicryl-embedded pancreatic tissue were exposed to specific antibodies (anti-insulin or anti-amylase), followed by B-pA. The unstained sections were examined using the ESI mode. In both cases, boron was detected with high resolution either at the level of the plasma membrane of acinar cells, demonstrating WGA binding sites, or over secretory granules in pancreatic insulin-secreting cells or acinar cells, demonstrating insulin and amylase, respectively. These findings were compared to those obtained with the protein A-gold technique, and have demonstrated the analogy of both types of labeling. In addition, several control experiments assessed this novel approach. They have demonstrated the specificity of labeling and the high reactivity of B-pA, as well as its antibody-binding properties. Finally, electron energy loss spectral analysis confirmed the presence of boron in the tissue sections at sites where immunolabeling was detected. These results demonstrate that ESI is an appropriate approach for cytochemistry. Since the technique is based on detection of elements, spatial resolution is considered to be in the magnitude of 0.5 nm, which represents a major improvement in resolution over actual electron microscopic cytochemical techniques.

scholarly journals Immunocytochemical localization of histamine in secretory granules of rat peritoneal mast cells with conventional or rapid microwave fixation and an ultrastructural post-embedding immunogold technique.

1992 ◽  
Vol 40 (9) ◽  
pp. 1247-1256 ◽  
Author(s):  
G R Login ◽  
S J Galli ◽  
A M Dvorak
Keyword(s):  
Electron Microscopy ◽  
Mast Cells ◽  
Guinea Pig ◽  
Secretory Granules ◽  
Fixation Method ◽  
Structural Localization ◽  
Thin Sections ◽  
Aldehyde Fixation ◽  
Peritoneal Mast Cells ◽  
Rat Peritoneal Mast Cells

We used a post-embedding immunogold labeling approach to define the fine-structural localization of histamine in rat peritoneal mast cells that were fixed using either standard aldehyde fixation or a fast microwave-aldehyde fixation method. Specimens were processed routinely for electron microscopy. Thin sections were exposed first to guinea pig antihistamine antiserum and then to gold-conjugated goat IgG directed against guinea pig IgG. By transmission electron microscopy, gold particles were localized to the matrix of cytoplasmic granules. Control sections treated with non-immune sera did not show labeling of mast cells. Adsorption of antihistamine antiserum with purified histamine or histamine bound to agarose showed a significant reduction (p less than 0.005) in granule staining. We also confirmed that our isolation procedures yielded functionally competent mast cells which released histamine when stimulated with sheep anti-rat IgE antiserum or with compound 48/80. These studies define the conditions of fixation for electron microscopy that are appropriate for the localization of histamine in the granule matrix of rat peritoneal mast cells.

scholarly journals Ultrastructural distribution of nuclear ribonucleoproteins as visualized by immunocytochemistry on thin sections.

1984 ◽  
Vol 98 (1) ◽  
pp. 358-363 ◽  
Author(s):  
S Fakan ◽  
G Leser ◽  
T E Martin
Keyword(s):  
Protein A ◽  
Nuclear Architecture ◽  
Gold Complex ◽  
Thin Sections ◽  
Border Regions ◽  
Core Proteins ◽  
Interchromatin Granules ◽  
Lowicryl K4m ◽  
Perichromatin Fibrils

The ultrastructural distribution of nuclear ribonucleoproteins (RNP) has been investigated by incubation of thin sections of mouse or rat liver, embedded in Lowicryl K4M or prepared by cryoultramicrotomy, with antibodies specific for RNP. The antibodies were localized by means of a protein A-colloidal gold complex. Anti-small nuclear (sn)RNP antibodies, specific for determinants of the nucleoplasmic snRNP species containing U1, U2, U4, U5, and U6 RNAs, were found associated preferentially with perichromatin fibrils, interchromatin granules, and coiled bodies. This indicates an early association of snRNP with structural constituents containing newly synthesized heterogeneous nuclear RNA. It also suggests a possible structural role of some snRNPs in nuclear architecture. Antibodies against the core proteins of heterogeneous nuclear RNP particles associate preferentially with the border regions of condensed chromatin, and in particular with perichromatin fibrils and some perichromatin granules. These results are discussed in view of recent knowledge about the possible role of nucleoplasmic RNP-containing components in the functions of the cell nucleus.

scholarly journals Application of lectin--gold complexes for electron microscopic localization of glycoconjugates on thin sections.

1983 ◽  
Vol 31 (8) ◽  
pp. 987-999 ◽  
Author(s):  
J Roth
Keyword(s):  
Endoplasmic Reticulum ◽  
Concanavalin A ◽  
Binding Sites ◽  
Light And Electron Microscopy ◽  
Gold Complex ◽  
Electron Microscopic ◽  
Gold Complexes ◽  
Thin Sections ◽  
Renal Tubular Cells ◽  
Lowicryl K4m

A method is described for the electron microscopic detection of lectin-binding sites in different cellular compartments and extracellular structures that uses thin sections from resin-embedded tissues. Various lectins (Ricinus communis lectin I and II, peanut lectin, Lotus tetragonolobus lectin, Ulex europeus lectin I, Lens culinaris lectin, Helix pomatia lectin, and soybean lectin) were bound to particles of colloidal gold and used for direct staining of thin sections or glycoprotein--gold complexes were prepared and applied in an indirect technique (concanavalin A and horseradish peroxidase--gold complex; wheat germ lectin and ovomucoid--gold complex). The details for preparation of such complexes from 14 nm gold particles are reported. The conditions of tissue processing that gave satisfactory staining results and good fine structure preservation were mild aldehyde fixation without osmification and low temperature embedding with the hydrophilic resin Lowicryl K4M. None of the so-called etching procedures was necessary prior to labeling of Lowicryl K4M thin sections. Examples of the use of this approach for detection of glycoconjugates in the rough endoplasmic reticulum, Golgi apparatus, and mucin of intestinal goblet cells as well as plasma membrane and various intracellular structures of absorptive intestinal and renal tubular cells are shown. A comparison is made with preembedding staining results on Concanavalin A-binding site localization in rat liver which shows that problems of penetration common in such a technique are circumvented by the postembedding approach described here. Concanavalin A-binding sites were not only consistently found in nuclear envelope, rough and smooth endoplasmic reticulum, plasma membranes, and collagen fibers, but also in mitochondria, glycogen, ribosomes, and nucleus. These data and those of a previous investigation (Roth J, Cytochem 31:547, 1983) prove the applicability of this cytochemical technique for postembedding localization of glycoconjugates by light and electron microscopy.

scholarly journals Electron microscopy of gold-labeled human and equine chromosomes.

1989 ◽  
Vol 37 (9) ◽  
pp. 1443-1447 ◽  
Author(s):  
P E Messier ◽  
R Drouin ◽  
C L Richer
Keyword(s):  
Electron Microscopy ◽  
Chromosome Banding ◽  
Protein A ◽  
Gold Complex ◽  
Chromosome Identification ◽  
Chromosomal Dna ◽  
Metaphase Chromosomes ◽  
Sister Chromatids ◽  
Antigen Localization ◽  
Chromatin Reorganization

We present an immunochemical technique for the detection of 5-bromo-2'-deoxyuridine (BrdU) incorporated discontinuously into the chromosomal DNA. A monoclonal anti-BrdU antibody and a protein A-gold complex were used to produce chromosome banding of human and equine chromosomes, specific for electron microscopy (EM). Well-defined bands, symmetry of sister chromatids, concordance between homologues, and band patterns similar to those observed by light microscopy facilitate chromosome identification and karyotyping. From prophase to late metaphase, chromosomes condense and bands appear to fuse. The fusion appears to be owing to chromatin reorganization. Our results underline the value of using immunogold reagents, which are ideal probes for antigen localization on chromosomes.

scholarly journals Quantitative immunocytochemical analysis of the induction of cytochrome P450IIB in rat hepatocytes.

1992 ◽  
Vol 40 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Y Fukui ◽  
A Yamamoto ◽  
R Masaki ◽  
K Miyauchi ◽  
Y Tashiro
Keyword(s):  
Electron Microscopy ◽  
Particle Density ◽  
Protein A ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
Immunoblot Analysis ◽  
Immunogold Electron Microscopy ◽  
Thin Sections ◽  
Gold Particles ◽  
Rough Er

We examined whether induction of the phenobarbital (PB)-inducible form of cytochrome P450 (P450IIB) in rat hepatocytes could be analyzed quantitatively by immunogold electron microscopy. Rats received intraperitoneal injections of PB every 24 hr and livers at the various stages of PB induction were fixed by perfusion with a mixture of paraformaldehyde (4%) and glutaraldehyde (0.1%) and embedded in LR White. Ultra-thin sections were cut and labeled by the protein A-gold procedure using affinity-purified anti-P450IIB antibody which was previously immunoabsorbed with liver microsomes from a control rat (not treated with PB). We counted the number of gold particles per micron of the rough ER membranes (particle density). Before PB treatment, the particle density of the rough ER in rat hepatocytes was practically zero and increased markedly at 48 and 72 hr after PB treatment. The rough microsomes were prepared from these PB-treated rat livers. The amount of P450IIB was estimated by immunoblot analysis and the number of gold particles bound to the rough microsomal membrane was determined by the same post-embedding immunogold procedure. The particle density of the rough microsomes increased in parallel with the increase in the amount of P450IIB, indicating good correlation of the two variables. Thus, the induction of cytochrome P450IIB can be quantitatively and reliably investigated by immunogold electron microscopy.

scholarly journals An improved immunocytochemical method for subcellular localization of serotonin in rat enterochromaffin cells.

1987 ◽  
Vol 35 (3) ◽  
pp. 319-326 ◽  
Author(s):  
O Nilsson ◽  
A Dahlström ◽  
M Geffard ◽  
H Ahlman ◽  
L E Ericson
Keyword(s):  
Osmium Tetroxide ◽  
Secretory Granules ◽  
Protein A ◽  
Ultrastructural Level ◽  
Proximal Colon ◽  
Intracellular Distribution ◽  
Thin Sections ◽  
Ec Cells ◽  
Immunocytochemical Method ◽  
A Minor

Serotonin-like immunoreactivity (5-HT-LI) has been localized at the ultrastructural level in enterochromaffin (EC) cells of rat gastrointestinal tract. Ultra-thin sections of tissues embedded in epoxy resin were incubated with 5-HT antisera and antibody binding sites were visualized with protein A-gold. Three different antisera were compared and were shown to require different fixation regimens for optimal preservation of 5-HT-LI. For one antiserum, tissues fixed in glutaraldehyde and osmium tetroxide could be used to demonstrate 5-HT-LI in EC cells. Immunocytochemical localization of 5-HT can thus be performed with good ultrastructural preservation of tissues. Quantitative evaluation of the intracellular distribution of 5-HT-LI was performed on EC cells from antrum, duodenum, and proximal colon, fixed in glutaraldehyde only. In all three locations, the majority of the gold particles (90%) in EC cells were localized over the dense core of the secretory granules, while a minor fraction (10%) were localized in parts of the cytoplasm devoid of granules. In EC cells fixed in glutaraldehyde and post-fixed in osmium tetroxide, 5-HT-LI was reduced by about 85%, although intracellular distribution was essentially the same as in cells fixed in glutaraldehyde alone. The results indicate that 5-HT in EC cells is stored mainly in secretory granules, with a small fraction of 5-HT being localized outside the granules.

scholarly journals Ultracytochemistry of calmodulin binding sites in myocardial cells by staining of frozen thin sections with colloidal gold-labeled calmodulin.

1989 ◽  
Vol 37 (2) ◽  
pp. 249-256 ◽  
Author(s):  
K Fujimoto ◽  
N Araki ◽  
K S Ogawa ◽  
S Kondo ◽  
T Kitaoka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Colloidal Gold ◽  
Biologically Active ◽  
Myocardial Cells ◽  
Thin Sections ◽  
Gold Particles ◽  
Calmodulin Binding ◽  
Tissue Sections

Calmodulin (CaM) has been implicated as a multifunctional regulator of Ca2+ in the cytoplasm of cells. We have recently introduced biologically active colloidal gold-labeled CaM as a marker for identifying potential CaM binding sites (unoccupied by endogenous CaM at the time of fixation) by electron microscopy and have stained frozen thin sections of rat cardiac muscle with this conjugate. In the presence of Ca2+, gold particles indicating CaM binding sites were found localized on the sarcoplasmic reticulum, mitochondria, and gap junctions. Control tissue sections treated with EGTA or exposed to excess amounts of unlabeled native CaM before staining showed no binding. We believe that cytochemistry of potential CaM binding sites revealed by staining with labeled exogenous CaM is useful in correlating known biochemical reactions of CaM with particular cell activities.

scholarly journals Electron microscopic immunocytochemical evidence for the involvement of the convertases PC1 and PC2 in the processing of proinsulin in pancreatic beta-cells.

1995 ◽  
Vol 43 (1) ◽  
pp. 11-19 ◽  
Author(s):  
D Malide ◽  
N G Seidah ◽  
M Chrétien ◽  
M Bendayan
Keyword(s):  
Beta Cells ◽  
Pancreatic Beta Cells ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Protein A ◽  
Gold Complex ◽  
Immunocytochemical Study ◽  
Electron Microscopic ◽  
Double Labeling ◽  
Endoproteolytic Cleavage

Endoproteolytic cleavage of pairs of basic amino acids is the key mechanism in the specific processing of precursor hormone molecules. Two endoproteases, PC1 (or PC3) and PC2, have recently been implicated in the conversion of proinsulin. Using antibodies against these proteases and proinsulin, followed by protein A-gold complex, we performed an immunocytochemical study for precise identification of the subcellular compartments involved in the processing of insulin. Both PC1 and PC2 immunoreactivities followed a pattern of gradually increasing density along the secretory pathway, being higher in the immature granules. Proinsulin labeling was detected in the Golgi apparatus and in the coated immature secretory granules located mainly in the Golgi area. Using double labeling, we demonstrated the presence of PC1 and/or PC2 in the majority of proinsulin-rich granules. In addition, we provided evidence that PC1 and PC2 are co-localized within the same granules. Co-expression of PC1 and PC2 with proinsulin in islet beta-cells indicates that these proteases are actively involved, probably in a sequential manner, in the conversion of proinsulin into insulin.

scholarly journals Electron microscopic localization of chromogranin A in osmium-fixed neuroendocrine cells with a protein A-gold technique.

1987 ◽  
Vol 35 (7) ◽  
pp. 795-801 ◽  
Author(s):  
S A Hearn
Keyword(s):  
Neuroendocrine Tumors ◽  
Chromogranin A ◽  
Osmium Tetroxide ◽  
Secretory Granules ◽  
Protein A ◽  
Neuroendocrine Cells ◽  
Neurosecretory Granules ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Carotid Body Tumors

An antibody (LK2H10) to chromogranin A has been recommended for use in ultrastructural identification of neuroendocrine secretory granules. Previous studies have demonstrated immunoreactive chromogranin A in specimens prepared for electron microscopy by glutaraldehyde fixation only. In this study, the effect of specimen post-fixation by osmium tetroxide on post-embedding localization of chromogranin A was evaluated. Human tissues from benign endocrine glands, neuroendocrine tumors, and non-neuroendocrine tumors were post-fixed in osmium, embedded in epoxy resin, and the sample thin sections immunolabeled using a protein A-gold technique. Chromogranin A-positive neurosecretory granules were detected in pancreatic islets, adrenal medulla, stomach, ileum, anterior pituitary, and parathyroid. Mid-gut carcinoids, bronchial carcinoids, pheochromocytomas, paragangliomas, carotid body tumors, and thyroid medullary carcinomas contained immunoreactive granules. Cytoplasmic granules in non-neuroendocrine tumors did not react for chromogranin A. Tissues post-fixed in osmium tetroxide had optimally preserved ultrastructural features, and use of this fixative is compatible with postembedding localization of chromogranin A in neurosecretory granules.

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