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Biomedical subjects

B W Moore

Publications and source records attributed to B W Moore.

At least 37 records · Page 2Linked to original sources
PubMed1984

Proteins of the brain extracellular fluid: evidence for release of S-100 protein.

Extracellular protein fractions were obtained (1) by mild, isotonic irrigation of freshly perfused brain tissue; (2) by collection of proteins released into superfusing medium by physiologically viable slices of rat hippocampus; and (3) by sampling the CSF of anesthetized rats. Analysis of the S-100 protein content of these fractions gave values of 2.8, 4.2, and 1.8 micrograms S-100/mg protein, respectively. These values were three- to sixfold higher than the S-100 content of the soluble cytoplasmic protein fractions from the same tissue. This several-fold higher S-100 content of the extracellular protein fractions relative to the intracellular cytoplasmic protein fractions indicates that S-100 is selectively released into the extracellular spaces of the brain. We suggest that the biological function of this CNS protein may involve intercellular transfer.

Animals↗
PubMed1982

Distribution of S-100 protein outside the central nervous system.

The distribution of S-100 outside the central nervous system in humans and rats was explored using antiserum to S-100 and the peroxidase anti-peroxidase method of Sternberger. In peripheral nerves the Schwann cells and the outermost part of the myelin sheaths were stained; axons were not. In dorsal root ganglia and ganglia of the autonomic nervous system only satellite cells were stained. In the adrenal medulla a considerable number of cells were stained. In all other organs studied Schwann cells and satellite cells of ganglia were the only elements that were stained. We conclude that S-100 could serve as a marker for Schwann cells in situ.

Adrenal Medulla↗
PubMed1982

Chemistry and biology of the S-100 protein.

The S-100 protein is specific for the nervous system and, being present in all vertebrates, shows a high degree of stability of structure during evolution. In adult animals it is primarily localized to glial elements, although there is some evidence that a small proportion may be present in neuronal nuclei or their plasma membranes. During development it is synthesized rapidly at a relatively late period of differentiation of the nervous system. In glioma cell cultures there is a control mechanism that seems to involve some kind of signal at the external surface of the plasma membrane, possibly specific cell-cell contact, to stimulate S-100 synthesis. All of these biological properties of S-100 suggest that it is connected with some specific essential function that is common to the nervous system of all vertebrates. Several chemical properties of S-100 provide clues to this function. It is an unusually acidic and soluble protein and, in the absence of Ca2+, has no detectable hydrophobic regions accessible to solvent. It is capable of specifically binding Ca2+, a process that causes S-100 to undergo a conformational change that exposes a hydrophobic region to the solvent and stimulates binding of S-100 to membranes. The conformational change and the membrane-binding properties are reversible when Ca2+ is removed and are antagonized by monovalent cations such as K+ and Na+. These chemical properties suggest that S-100 may, as part of its function in the nervous system, be bound to some hydrophobic site, possibly a membrane, and that the extent of this binding is regulated by concentrations of Ca2+, K+ and Na+. If this is true, then it is important, as the next step in working out its function, to discover the exact site where S-100 binds in the nervous system.

Amino Acid Sequence↗
PubMed1981

Demonstration of five major glycoproteins in myelin and myelin subfractions.

Myelin was found to contain five major glycoproteins with molecular weights of 120000, 95000, 88000, 43000 and 38000. Light myelin contained only 5-7% of the amount of these glycoproteins in whole myelin, whereas heavy myelin and the membrane fraction contained amounts nearly identical with whole myelin. Since all the major and minor glycoproteins, with the exception of 120000-mol-wt. glycoprotein, were detected only after treating the myelin membrane with neuraminidase, N-acetylneuraminic acid is a terminal sugar residue in these glycoproteins.

Animals↗
PubMed1980

Octopus calmodulin. Structural comparison with bovine brain calmodulin.

A protein previously isolated from octopus optic lobe is shown to have the biochemical characteristics of a calmodulin-like protein. The amino acid composition of the octopus calmodulin is similar to that of another sea invertebrate calmodulin, from Renilla reniformis, in that both contain a single residue of tyrosine which distinguishes them from the vertebrate calmodulins which contain two tyrosines. The 1H NMR spectra of the octopus calmodulin and bovine brain calmodulin are compared in their apo- and calcium-saturated conformations. A comparison of these spectra indicates that the single tyrosine of the octopus calmodulin is in a structurally homologous position to tyrosine-138 of bovine brain calmodulin. 1H NMR and UV difference spectroscopy also demonstrate that the solution conformations of the apo- and calcium-saturated forms of octopus calmodulin are very similar to those of bovine brain calmodulin. It is concluded that both proteins undergo similar calcium-induced changes in tertiary structure, which result in near identical solution conformations.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1980

An improved method of preparing rat brain synaptic membranes. Elimination of a contaminating membrane containing 2',3'-cyclic nucleotide 3'-phosphohydrolase activity.

Synaptosomes were prepared from rat cortex by subjecting a washed crude mitochondrial pellet to centrifugation first on discontinuous Ficoll-isotonic sucrose gradients and then on discontinuous sucrose gradients. The synaptosome fraction, collected from the 7.5-14% Ficoll band (II), was further separated into two additional fractions, designated IIA and IIB, which bank at the 0.32-1.05 M and at the 1.05-1.6 M sucrose interfaces, respectively. Electron microscopic analysis showed that fraction IIB contained synaptosomes and extra terminal mitochondria and was essentially free of membrane fragments. Further characterization showed that IIB contained 69% of the protein and 83% of the lactic dehydrogenase activity of fraction II and had a specific activity of a 2',3'-cyclic nucleotide 3'-phosphohydrolase approximately 1% of that obtained with myelin. Fraction IIA had approximately 50% the specific activity of the 2',3'-cyclic nucleotide 3'-phosphohydrolase found in myelin. Synaptic plasma membranes were prepared by lysing fraction IIB in 1 mM sodium phosphate, 0.1 mM EDTA at pH 8.5 and subjecting this preparation to centrifugation on a discontinuous sucrose density gradient. Enzymatic analysis indicated that membranes banding at the 0.6-0.8 M sucrose interface had high specific activities of plasma membrane enzymes (e.g. acetylcholinesterase, ATPase, 5'-nucleotidase). The specific activity of the (Na+ + K+)-ATPase in the purified membrane preparation was 8-fold higher than that in the original homogenate. Specific activities of various marker enzymes indicated that the composition of these membrane preparations for the most part was synaptic plasma membranes, approximately 7% mitochondrial outer membranes and 3% a membrane containing 2',3'-cyclic nucleotide 3'-phosphohydrolase activity. The polypeptide compositions of three possible contaminating membranes and of synaptic membranes were compared by electrophoresis in 6-20% gradient polyacrylamide gels in the presence of sodium dodecyl sulfate. Whereas mitochondrial and myelin membranes had distinct compositions, the compositions of the microsomal and synaptosomal plasma membranes were similar. Synaptic plasma membranes contained at least 27 polypeptides; the three major polypeptides had molecular weights of 103,000; 54,000; and 50,000. The major polypeptides of soluble synaptosomal proteins had molecular weights of 54,000 and 42,000.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1980

Regulation of the synthesis of S-100 protein in rat glial cells.

The influence of serum on the synthesis of the nervous system specific S-100 protein has been investigated in the rat glial cell clone C61a. In sparse cells, where S-100 synthesis is low, removal of serum leads to a 2- to 3-fold increase of the rate of S-100 synthesis relative to total soluble cell protein. Measurements of S-100 content by radioimmunoassay showed that sparse cells are accumulating S-100 much more rapidly in the absence of serum. Our findings suggest that serum components inhibit the expression of S-100 synthesis in sparse cells by a concentration-dependent mechanism. This effect does not correlate directly with the reduced cellular growth rate in low serum or serum-free medium. Lipid-free medium, which has little growth-promoting activity, maintains the capacity to lower the rate of S-100 synthesis. A partially purified extract of platelets can substitute for serum in repressing the synthesis of the S-100 protein.

Animals↗
PubMed1980

Organ of Corti-specific polypeptides: OCP-I and OCP-II.

Two polypeptides, OCP-I and OCP-II, specific to the organ of Corti of the quinea pig and the rate, were detected by two-dimensional polyacrylamide gel electrophoresis. They were neither present in other inner ear structures, nor in other organs tested. The two polypeptides constitute a substantial portion of the total protein of the organ of Corti. Both inner and outer layer of the organ of Corti contained approximately equal amounts of OCP-I and OCP-II. The molecular weights of OCP-I and OCP-II are 37,000 and 22,500 daltons, respectively. The corresponding pI values are 4.9 and 5.1, respectively. in addition, actin and tubulin were detected in both layers of the organ of Corti.

Animals↗
PubMed1980

Investigation of the axonal transport of three acidic, soluble proteins (14-3-2, 14-3-3, and S-100) in the rabbit visual system.

The question of whether three acidic, water-soluble proteins (14-3-2, 14-3-3, and S-100, the first and last known to be brain-specific) are axonally transported was investigated in the rabbit visual system. The water-soluble proteins were obtained from individual optic nerves, combined optic tracts and lateral geniculate bodies, superior colliculi, and, in some instances, retinas at various times (1--56 days) after monocular injections of [3H]leucine. These proteins were separated by a two-step polyacrylamide gel electrophoresis procedure that isolated 14-3-2, 14-3-3, and S-100 almost uncontaminated by other radioactivity. The isolated 14-3-2 and S-100 were demonstrated to be approx. 90% pure by a new method based on retarding the migration of these proteins by immunoadsorption during the first step of electrophoresis. An analysis of the radioactive labeling of the total soluble proteins (TSP) and the isolated acidic proteins revealed that: (1) S-100 was not axonally transported; (2) both 14-3-2 and 14-3-3 were part of one of the slow components of axonal transport (2--4 mm/day); (3) the radioactivity of 14-3-2 and 14-3-3 represented about 2.7% and 3.2%, respectively, of the radioactivity incorporated into the axonally transported TSP; (4) the ultimate distributions of the radioactively labeled 14-3-2 and 14-3-3 were the same (about 70% of each destined for the superior colliculus) and differed from that of the TSP; and (5) the rates of catabolism of the axonally transported 14-3-2 and 14-3-3 were slightly greater than that of the TSP, with half-lives for 14-3-2 and 14-3-3 estimated to be 11 and 10 days, respectively.

Animals↗
PubMed1980

Axonal transport of the Ca2+-dependent protein modulator of 3':5'-cyclic-AMP phosphodiesterase in the rabbit visual system.

Water-soluble proteins were extracted from individual retinas, optic nerves, combined optic tracts and lateral geniculate bodies, and superior colliculi of rabbits at 1, 3, and 18 days after injection of [3H]leucine into the right eye. The Ca2+-dependent protein modulator of 3':5'-cyclic-AMP phosphodiesterase (calmodulin) was isolated from these samples by a two-step polyacrylamide gel electrophoresis procedure. An analysis of the radioactivity incorporated into the total soluble proteins and the calmodulin revealed that most of the calmodulin was axonally transported at a slow rate (2--4 mm/day) and represented about 0.45% of the total transported soluble protein.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1978

Drug-induced differentiation of a rat glioma in vitro: II. the expression of S-100, a glial specific protein and steroid sulfatase.

Amethopterin and 5-bromodeoxyuridine (BUdR) were used to induce morphological changes in cloned rat glioma (C6). The expression of S-100 protein, an acidic protein localized in glial cells, and steroid sulfatase, an ubiquitously distributed enzyme found in high concentration in glial cells, were followed during cell growth, from subculture to well into the stationary phase of control and drug-treated cultures. Amethopterin and BUdR differed in their effects on glioma morphology and in the expression of the biochemical parameters. Amethopterin coordinately stimualted both the production of S-100 protein and steroid sulfatase activity when cell division was inhibited during early logarithmic growth phase. BUdR stimulated steroid sulfatase activity but repressed production of S-100 protein. The results are discussed with respect to the mechanism of regulation of the differentiated state of tumor cells.

Animals↗
PubMed1977

Preparation and properties of the brain specific protein 14-3-2.

A brain specific protein, 14-3-2, has been isolated from bovine brain by the use of ammonium sulfate precipitation, gel filtration on Sephadex G-150, and ion exchange chromatography on DEAE-cellulose and DEAE-Sephadex. It is an acidic protein, in agreement with the high content of glutamic and aspartic acid, that is composed of a single polypeptide chain of mol. wt. 50,000. Immunochemical tests using antiserum to purified 14-3-2 showed that the protein is present in at least 100-fold greater amounts in brain than in any other rat tissue. Furthermore, 14-3-2 was found in brains of a number of vertebrate species, although the antigen is apparently not entirely identical in all species tested. The protein 14-3-2 can be considered to be a species non-specific protein which is neuronal in origin.

Amino Acid Sequence↗
PubMed1977

The subunit structure of bovine brain 14-3-2.

Two aspects of the subunit structure of the bovine brain specific protein 14-3-2 have been examined. On the one hand, native 14-3-2 has been separated into two fractions by hydroxylapatite chromatography. One eluted at the same position when chromatographed on the same column, while the other redistributed into the same two fractions again. Amino acid analysis of these two forms of 14-3-2 gave results that were not significantly different under the condition of analysis. Furthermore, when each peak was subjected to cyanogen bromide cleavage, very similar elution profiles of the resultant fragments were obtained. The two pools also cross-reacted with antiserum to 14-3-2. Reaction of purified 14-3-2 with dimethylsuberimidate caused the formation of covalently bound protein units of 100,000 molecular weight when measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis, as opposed to the 50,000 minimal molecular weight normally detected. On the other hand, analysis of the soluble tryptic peptides of S-[14C]carboxymethyl 14-3-2 yielded only three distinct radioactive peptides, each with one residue of S-carboxymethylcysteine whereas 8 are expected on the basis of the amino acid composition of the 50,000 molecular weight polypeptide chains. Thermolysin digestion of a similarly modified 14-3-2 preparation yielded all of the radioactivity in 5 S-carboxymethylcysteine-containing peptides. The partial amino acid sequence of these peptides indicates that they represent 4 unique areas of the polypeptide chain. Since 8 such peptides were expected, that is, double the number found, the minimum structural unit of the protein must be of 25,000 molecular weight. The results of these experiments do not permit distinction between a duplication of the structure within a single polypeptide chain or the alternate possibility of two polypeptide chains bound by unusually strong non-covalent bonds. These results suggest that 14-3-2 is a covalently linked dimer of 25,000 mol.wt. units that can aggregate to form larger species of 100,000 mol.wt. and higher.

Amino Acid Sequence↗