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Biomedical subjects

A Bignami

Publications and source records attributed to A Bignami.

At least 109 records · Page 6Linked to original sources
PubMed1978

Neurofilament protein in clonal lines of mouse neuroblastoma.

As indicated by immunofluorescence with neurofilament antiserum and by electron microscopy two neuroblastoma clones in suspension culture contained a pool of neurofilament subunits which could be induced to assemble into filaments following exposure to vinblastine and colchicine. Under the same culture conditions neuroblastoma cells treated with aluminum extended thick processes with many filaments. The processes were much smaller in nontreated cells but still contained bundles of filaments. These filaments persisted after inhibition of protein synthesis by cycloheximide. In the long neurites formed by cells attached to plastic immunofluorescence with neurofilament antiserum was particularly intense at the growth cone.

Aluminum↗
PubMed1977

Preparation of antisera to neurofilament protein from chicken brain and human sciatic nerve.

Antigens isolated by hydroxyapatite chromatography from human sciatic nerve (SN1 protein) and from 8 M urea extracts of chicken brain were selectively localized by immunofluorescence to neurofibrils in rat and chicken CNS. Absorption of the antisera with SN1 protein, chicken antigen or GFA protein abolished the staining. Antisera raised against antigen isolated with the same procedure from buffer extracts of chicken brain stained both neurofibrils and glial fibrils by immunofluorescence. Neurofibrillary staining was selectively abolished by absorption of the antisera with SN1 protein. Antisera prepared against axonal preparations isolated from bovine white matter only stained astroglia and were thus undistinguishable from anti-GFA sera in this respect. The data suggested that the protein subunits of neurofilament and glial filaments, although difficult to separate in brain extracts by standard biochemical procedures and by subcellular fractionation in bovine white matter, still retain immunological specificity. In addition, the immunological cross reactivity between human and chicken antigens suggested that neurofilaments, as other constituents of the cytoskeleton such as microtubules and actin microfilaments, show a high degree of evolutionary stability.

Animals↗
PubMed1977

Structural properties of the glial fibrillary acidic protein. Evidence for intermolecular disulfide bonds.

Glial fibrillary acidic protein was purified from 4 M urea extracts of bovine brain by DEAE Bio-Gel A chromatography, 30% ammonium sulfate precipitation and hydroxylapatite chromatography. Subunits of about 54 000 daltons are present in solution as polydisperse distributions of polymers largely constrained by the presence of interchain disulfide linkages. Circular dichroism measurements indicate a native conformation containing some alpha-helical structure. The relevance of these findings to the cytoskeletal function of intermediate (80-100 A) filaments is discussed.

Animals↗
PubMed1977

Ultrastructural localization of glial fibrillary acidic protein in mouse cerebellum by immunoperoxidase labeling.

Glial fibrillary acidic protein was localized at the electron microscope level in the cerebellum of adult mice by indirect immunoperoxidase histology. In confirmation of previous studies at the light microscope level, the antigen was detectable in astrocytes and their processes, but not in neurons or their processes, or in oligodendroglia. Astrocytic processes were stained in white matter, in the granular layet surrounding synaptic glomerular complexes, and in the molecular layer in the form of radially oriented fibers and of sheaths surrounding Purkinje cell dendrites. Astrocytic endfeet impinging on meninges and perivascular membranes were also antigen positive. In astrocytic perikarya and processes, the immunohistochemical reaction product appears both as a diffuse cytoplasmic label and as elongated strands, which by their distribution and frequency could be considered glial filaments.

Animals↗
PubMed1977

Specificity of the glial fibrillary acidic protein for astroglia.

Glial fibrillary acidic protein (GFA) is the main constituent of glial filaments and the close similarity of GFA and neurofilament protein has been recently reported. However, the immunofluorescence staining of peripheral nerve which may be observed with GFA antisera is not due to cross-reaction between GFA and neurofilament protein. Staining of peripheral axons was also observed with control sera obtained by injecting the rabbits with nonimmunogenic GFA preparations isolated with the same procedure. Immune GFA antisera and control sera reacted with sodium dodecyl sulfate extracts of sciatic nerve. However, the precipitin line formed with peripheral nerve crossed the line against GFA protein, thus indicating nonidentity between the two antigens. Buffer extract of sciatic nerves that had been incubated with spinal cord reacted by immunodiffusion with GFA antisera, thus indicating that redistribution of GFA occurred under these conditions.

Animals↗