Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

Exposure of mycobacterial growth inhibitory factor (MycoIF) to trypsin, chymotrypsin, or neuraminidase decrease its ability to produce intracellular inhibition of mycobacterial growth within macrophages, suggesting that MycoIF was a glycoprotein. MycoIF was unaffected by deoxyribonuclease or ribonuclease. Supernatant fluids from antigenically stimulated H37Ra-immunized mouse spleen cells exposed to puromycin were unable to produce significant intracellular inhibition. This indicated that the presence of MycoIF activity in supernatant fluids required protein synthesis. The filtration of MycoIF-containing supernatant fluids on Sephadex G-150 demonstrated that significant MycoIF activity appeared only in those fractions which eluted on the downward side of the serum albumin peak. Based on protein standards filtered through the Sephadex gel, the molecular weight of MycoIF was calculated to be between 20,000 and 35,000. These calculations assumed that MycoIF is a globular protein. Attempts to purify MycoIF by anion exchange chromatography (diethylaminoethylcellulose) was not successful.
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PMID:Molecular weight and other characteristics of mycobacterial growth inhibitory factor produced by spleen cells obtained from mice immunized with viable attenuated mycobacterial cells. 81 60

Bovine serum albumin, free of deoxyribonuclease activity, was obtained in our laboratory using ion-exchange chromatography followed by acetylation. Chromatography on four different resins (DEAE-52, P-11, hydroxylapatite and Q Sepharose fast-flow) was examined. Fractions from Q Sepharose chromatography, eluted with a linear gradient 0-1.0 M NaCl and subsequently acetylated, proved to be the most effective method for obtaining deoxyribonuclease-free bovine serum albumin.
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PMID:A protocol for the purification of bovine serum albumin free of deoxyribonuclease activity. 226 30

Longitudinal muscle strips adhered with myenteric plexus were subjected to enzyme digestion under controlled conditions in a Krebs-bicarbonate buffer solution containing a mixture of collagenase, deoxyribonuclease, protease, choline chloride, and bovine serum albumin for 30 min at 37 degrees C. Myenteric ganglia, singly or in multiple aggregates, were harvested with micropipette and labeled with [3H]choline for [3H]acetylcholine (ACh) release studies. When examined by light or electron (transmission or scanning) microscopy, the ganglia exhibited their normal structural characteristics with axon bundles, dendrites, cell bodies, and vesiculated processes. Depolarization with elevated potassium or veratrine hydrochloride significantly elevated the efflux of [3H] ACh. Perfusion with tachykinins (substance P and substance K), vasoactive intestinal peptide, forskolin, or serotonin also significantly increased the release of [3H]ACh. This study demonstrated that enzyme-dissociated myenteric ganglia, notably free of muscle or connective tissue components, were structurally well preserved and were amenable to functional studies targeted specifically for the enteric plexus neurons.
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PMID:Characterization of acetylcholine release from enzyme-dissociated myenteric ganglia. 253 38

Concanavalin A, a specific glycoprotein probe, was optimally labelled to a maximum stoichiometry of 0.4 mol of chlorotriazinylaminofluorescein (CTAF)/mol of concanavalin A monomer under mild reaction conditions (pH 8.0, 6 h), and under these conditions the CTAF concanavalin A preparation retains its carbohydrate-binding ability and is able to penetrate SDS/7.5-15%-polyacrylamide gradient gels. CTAF-concanavalin A gives fluorescent bands for the glycoproteins transferrin, fetuin and deoxyribonuclease and shows no fluorescent response for the non-glycoproteins bovine serum albumin and soya-bean trypsin inhibitor. The detection limit of sensitivity for CTAF-concanavalin A, which is similar to that of fluorescein isothiocyanate-concanavalin A, is in the range 5-25 micrograms of glycoprotein. CTAF-concanavalin A is a suitable probe for the detection of glycoproteins in higher-percentage (greater than or equal to 10%) SDS/polyacrylamide gels, and will probably have other applications in, for example, fluorescent energy transfer and other structure-function studies.
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PMID:The synthesis of fluorescent chlorotriazinylaminofluorescein-concanavalin A and its use as a glycoprotein stain on sodium dodecyl sulphate/polyacrylamide gels. 363 34

Antigen-retaining follicular dendritic cells (FDC) have been identified and studied in sections of lymph nodes and spleen, but studies of these cells in culture have been extremely limited. The purpose of this study was to establish techniques to release these fragile cells from mouse lymph nodes in a viable state and to identify these cells routinely in lymph node cell suspensions. FDC were obtained from passively or actively immunized popliteal lymph nodes of mice injected in the footpads with 125I-labeled human serum albumin (HSA) or horseradish peroxidase (HRP). Lymph nodes were removed 1 hr after the footpads had been injected with collagenase. After another hour of incubation in vitro with collagenase, protease, and deoxyribonuclease, FDC were released by gentle teasing and enriched by centrifugation on a low density bovine serum albumin (BSA) or Percoll gradient. Most FDC with the associated radiolabel floated at densities greater than 1.06 g/ml on BSA or Percoll gradients. Slides of the FDC-enriched fraction were prepared, using a cytobucket which allowed the cells to be affixed to glass slides by centrifugation in a less disruptive manner than by cytocentrifugation. FDC that were air-dried and fixed with 3% glutaraldehyde had a characteristic pink acidophilic cytoplasm after Wright's staining, and had a faintly basophilic euchromatic nucleus frequently with peripherally-clumped chromatin. In addition, these cells were large and irregularly shaped (up to 60 micron long). Fixation of FDC with 0.6% paraformaldehyde/ 0.9% glutaraldehyde on poly-L-lysine-coated slides resulted in a preservation of FDC which made possible visualization of long dendritic processes by Nomarski optics. Antigen presence on the cell surface was confirmed by autoradiography and, in the case of HRP, was also visualized enzymatically using diaminobenzidine. In contrast to resident peritoneal macrophages or some contaminating lymph node macrophages present on the same slides, FDC did not phagocytize opsonized sheep red blood cells (SRBC) or adhere to plastic surfaces although they did form rosettes with opsonized SRBC. Cell marker studies indicated FDC have a distinctive phenotype. They were positive for Ia, Fc receptor, and leukocyte common antigen, but negative for Thy-1, Ly-1, Ly-2, endogenous Ig, Mac-1, Mac-2, Mac-3, and F4/80, and negative to weakly positive for nonspecific esterase. Cultured FDC remained viable and retained radiolabeled antigen-antibody complexes on their surfaces and were significantly enriched for FDC.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Follicular dendritic cells in suspension: identification, enrichment, and initial characterization indicating immune complex trapping and lack of adherence and phagocytic activity. 396 23

Deoxyribonucleic acid (DNA)-mediated transformation of Bacillus subtilis can be inhibited by antibodies which specifically interact with single-stranded DNA. This inhibition occurs at a time when the transformation reaction is insensitive to deoxyribonuclease. Studies with radioactive proteins revealed that the maximal binding of gamma globulin occurs immediately preceding the development of maximal competence in the population. Other proteins, such as deoxyribonuclease cytochrome c and serum albumin also adsorb to the surface of the cell. After treatment with lysozyme, 67% of the radioactive gamma globulin remains associated with the cytoplasmic membrane. These findings suggest that the DNA is complexed in a deoxyribonuclease-insensitive form to the surface of the cell and is converted to a single-stranded state prior to transport past the membrane and integration into the chromosome.
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PMID:Binding of rabbit gamma globulin by competent Bacillus subtilis cultures. 418 94

An "immunogenic" ribonucleic acid (Im-RNA) has been extracted from peritoneal exudate (PE) cells of rats that were immunized with sheep erythrocytes (SRBC). Following multiple phenol extractions and deoxyribonuclease treatment, the material obtained from PE cells was eluted from diethylaminoethyl-cellulose at 0.55 M NaCl concentration and partially purified in this procedure by a factor of 7- to 10-fold. After column chromatography, Im-RNA was found to be free of antigen based on results using (51)Cr-labeled SRBC or (14)C-dinitrophenol coupled to methylated bovine serum albumin as antigens. The Im-RNA showed a biphasic hyperchromicity curve when heated. The first phase, from 30 C to 90 C was gradual, accounting for 15.2% hyperchromicity suggestive of transfer RNA melting. No loss in immunogenic activity was observed when the Im-RNA was heated to 90 C. The second phase, from 90 C to 102 C, accounting for 15.2% further hyperchromicity, had a calculated T(m) of 96 C. Heating above 90 C resulted in an irreversible loss of immunogenic activity. These results strongly suggested that the RNA fraction contained a highly ordered secondary structure such as might be found with double-stranded nucleic acid. The nature and function of the Im-RNA is discussed.
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PMID:Preliminary characterization of "immunogenic" ribonucleic acid derived from rat peritoneal exudate cells. 457

Extracellular rabies virus, grown in monolayer cultures of BHK21 cells in the presence of medium supplemented with bovine serum albumin, was purified by the following procedure. Virus was precipitated from infectious tissue culture fluid by zinc acetate and was resuspended in a solution of ethylenediaminetetraacetate. The suspension was filtered through a Sephadex column and was treated with ribonuclease and deoxyribonuclease. The virions were then pelleted by centrifugation at high speed and were resuspended in buffer solution. Banding of the virus by centrifugation in a sucrose density gradient was the final step in the purification procedure. Purified preparations contained bullet-shaped virus particles of variable length and little (up to 5%) contaminating host-cell material. Most of the virions were "complete", i.e., 180 nm long, but some virus particles were shorter. The length distribution of the virions was nonrandom. Shorter virions seemed to be noninfectious and showed markedly decreased hemagglutinating activity. The complement-fixing activity and the ribonucleic acid to protein ratio of the virions were not related to the length of the virus particles. Although the properties of extracellular and intracellular viruses were similar, the procedure was not suitable for purification of intracellular rabies virus.
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PMID:Purification of rabies virus grown in tissue culture. 497 71

Infectious entities, extractable, with phosphate buffer, from tissue infected with potato spindle tuber virus and inciting symptoms on tomato that are typical of this virus, have properties incompatible with those of conventional virus particles. The infectious particles sediment in sucrose density gradients at approximately the same rate as particles with a sedimentation coefficient of 10S, are insensitive to treatment with organic solvents, and can be concentrated by ethanol precipitation. Treatment with phenol changes neither their infectivity nor their sedimentation properties. Infectivity is insensitive to deoxyribonuclease, but at low ionic strength it is sensitive to ribonuclease. At high ionic strength, infectivity partially survives incubation with ribonuclease. These properties, as well as elution patterns from columns of methylated serum albumin, suggest that the extractable infectious agent may be a double-stranded RNA.
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PMID:Potato spindle tuber virus: a plant virus with properties of a free nucleic acid. 606 89


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