Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.21.1 (DNase)
7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transcriptional activity of genes that have randomly integrated into the genomes of transfected cells and transgenic organisms is in general unpredictable, varying with the chromosomal site of the insertion. This effect of chromosomal position on gene expression may reflect the organization of chromosomes into topologically constrained loops and functional domains. To assess the biological significance of these loop domains, the anchorage of DNA to the nuclear scaffold has been studied at specific gene loci. We have previously defined cis-acting regions flanking the chicken lysozyme-gene domain that mediate the attachment of the chromatin to the nuclear scaffold. These 'A-elements' map to the 5' and 3' boundaries of the region of general DNase sensitivity in the active chromatin, which contains the lysozyme gene and its cis-regulatory elements. Here we report that when a reporter gene is flanked by 5' A-elements from the lysozyme gene, its expression in stably transfected cells is significantly elevated and is independent of chromosomal position.
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PMID:A nuclear DNA attachment element mediates elevated and position-independent gene activity. 279 52

Two rapid methods were evaluated for their extraction of plasmids from Clostridium perfringens. The first method involved lysis of 1 to 2 ml of C. perfringens culture by treatment with hyaluronidase, lysozyme, and sarcosyl. DNA, extracted with phenol-chloroform, was treated with RNase, boiled, and electrophoresed in a 1.2% agarose gel. The second method involved lysis of 2 ml of culture by lysozyme treatment and extraction with alkaline sodium dodecyl sulfate (SDS). Extracted DNA was treated with RNase, boiled, and electrophoresed in a 0.7% agarose gel. Of 57 strains of C. perfringens analyzed by both extraction procedures, 11 were shown to have plasmids by the alkaline SDS method which were missed by the phenol-chloroform extraction method. These new plasmids were of higher molecular mass and ranged up to 68 megadaltons. Use of the DNase inhibitor diethyl pyrocarbonate did not further improve the yield of plasmid DNA. An additional 159 isolates of C. perfringens screened by the alkaline SDS method revealed plasmids up to 80 megadaltons in mass and an overall plasmid carriage rate of 69%.
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PMID:Rapid extraction of plasmids from Clostridium perfringens. 287 Jun 80

Replacement of the amino-terminal 40-amino-acid region of the 588-amino-acid precursor of the membrane-bound penicillin-binding protein 3 (PBP3) by the decapeptide MKGKEFQAWI was carried out by altering the amino-coding end of the ftsI gene. Insertion of the modified gene into a runaway-replication plasmid under the control of a fused lpp promoter and lac promoter/operator, resulted in the overexpression by Escherichia coli of the modified PBP3 (designated PBP3**) in the cytoplasm. About 80% of the accumulated PBP3** underwent sequestration in the form of insoluble protein granules that were isolated by cell breakage or cell lysis. After selective removal of contaminants by an EDTA-lysozyme/DNase (deoxyribonuclease)/Nonidet extraction, treatment of the granules with guanidinium chloride followed by dialysis against buffer containing 0.5 M NaCl yielded a refolded, water-soluble PBP3**, which, upon chromatography on Superose 12, exhibited the expected 60,000 molecular mass. The refolded PBP3** bound benzylpenicillin in a 1 to 1 molar ratio, was highly sensitive to aztreonam and showed the same degree of thermostability, in terms of penicillin-binding capacity, as the parent, membrane-bound PBP3, suggesting that protein refolding occurred with formation of the correct intramolecular interactions. Two to three mg of refolded PBP3** can be obtained from 1 litre of culture of the overproducing strain.
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PMID:Overexpression, solubilization and refolding of a genetically engineered derivative of the penicillin-binding protein 3 of Escherichia coli K12. 305 Mar 60

Streptococcus faecalis S-48 produces a broad spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. This substance is produced in solid and liquid media and also in a defined basal medium. It is sensitive to protease, pronase, or trypsin, heating at 70 degrees C, and alkaline pH, but resistant to treatment with lipase, lysozyme, alkaline phosphatase, DNAase, RNAase, acidic or neutral pHs, and also lower temperatures (60 degrees C). Several organic solvents cause precipitation, but not inactivation. This antibiotic has been partially purified by gel filtration and further ion-exchange chromatography. Its molecular weight has been estimated close to 2000. The biological activity of this antagonistic substance against the selected indicator strains, Streptococcus faecalis S-47 and Escherichia coli U-9, is bactericidal. The characterization of this substance, initially classified as a bacteriocin, indicates that it is an antibiotic of peptidic nature. The significance of antibiotic occurrence in group D of the genus Streptococcus is also discussed.
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PMID:Characterization and partial purification of a broad spectrum antibiotic AS-48 produced by Streptococcus faecalis. 309 96

The chicken lysozyme gene is constitutively expressed in macrophages and controlled by steroid hormones in the oviduct. We have investigated the influence of the 5' noncoding region of this gene on its cell-specific transcriptional activation. In transient transfection experiments we have identified a far-upstream cell-specific enhancer element 6.1 kb 5' to the transcriptional start site of the lysozyme gene. Transcription from the lysozyme gene promoter is induced by this element in a position- and orientation-independent manner in lysozyme-producing myeloid cells (HBCI), but not in non-producing chicken embryo fibroblasts (CEF-38). The enhancer region correlates with a DNase-hypersensitive chromatin site which is only detectable in cells of tissues in which the lysozyme gene is transcribed. We suggest that this far-upstream element is involved in the tissue-specific control of lysozyme gene activity.
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PMID:The lysozyme enhancer: cell-specific activation of the chicken lysozyme gene by a far-upstream DNA element. 345 87

DNA can be encapsulated into lipid vesicles formed by sonication. The presence of a basic protein, lysozyme, enhances the incorporation 100-fold above the level expected by random trapping. This is demonstrated by the ability of the lipid vesicles to protect DNA from digestion with DNase. Such an enhancement of nuclei acid incorporation into vesicles by basic polypeptides and the sharply increased concentration of these macromolecules in the internal volume may have been advantageous in prebiotic evolution.
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PMID:Basic protein enhances the incorporation of DNA into lipid vesicles: model for the formation of primordial cells. 347 Jul 72

Mycobacterium paratuberculosis, the causative agent of paratuberculosis, produces considerable economic loss in the cattle industry in many countries. The slow growth of M. paratuberculosis has hindered investigations of the antigenic composition of the organism and the development of species-specific antigen for serological detection of this disease. This paper describes a simple method for the isolation of large quantities of viable M. paratuberculosis from the intestinal mucosa of infected cattle by a combination of trypsin digestion, deoxyribonuclease/lysozyme treatment and differential centrifugation. Purity was about 99% and yield between 10(5)-10(9) bacteria/g tissue.
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PMID:A technique for the purification of Mycobacterium paratuberculosis from the ileal mucosa of infected cattle. 353 28

In order to construct an in vitro recombination system of T7 DNA, the reaction products of which resemble those in vivo in structure, T7 DNA-membrane complex which is free from concomitant DNase activity was purified from T7 phage-infected cells. T7-infected cells were lysed with T4 lysozyme/Brij58, and T7 DNA-membrane complex was purified through three successive density gradient centrifugations. The properties of the complex on exposure to defined nucleases and observation of the complex by electron microscopy revealed that in T7 DNA-membrane complex, both ends of a linear T7 DNA are bound with membrane components. A mixture of 32P-labeled T7 DNA-membrane complex and BU-labeled T7 DNA-membrane complex was incubated with T7 exonuclease and T7 DNA-binding protein, and the reaction products with intermediate density were purified. Most of the products were found to have structures similar to that of the recombination intermediate found in T7-infected cells upon electron microscopic examination.
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PMID:Purification of bacteriophage T7 DNA-membrane complex and its application to the in vitro recombination reaction. 391 87

A method has been developed for the isolation of outer membranes from Acinetobacter sp. strain MJT/F5/199A. Washed cells were broken in a French press and, after deoxyribonuclease and ribonuclease treatment, removal of intact cells, and four washes in 20 mosmol phosphate buffer, pH 7.4, with centrifugation at 25,000 x g for 10 min, preparations of cell wall fragments from which almost all pieces of plasma membrane had been removed resulted. Treatment of the cell walls with lysozyme and further washing, in the presence of 20 mM MgCl(2), yielded preparations of outer membranes. Electron microscopy of freeze-etched preparations shows that a regular pattern of subunits is present on the outer surfaces of intact cells. After negative staining, these subunits are visible on isolated walls and outer membranes; they can be removed by brief treatment with papain. In section, the cell wall structure is that typical of gram-negative bacteria, but the subunits are not detectable on the surface of the outer membrane. The outer membrane retains the appearance of a "unit membrane" in the cell wall, isolated outer membrane, and papain-treated outer membrane fractions. Both cell walls and outer membranes contain a high percentage of protein (76 and 84%, respectively) and not more than 5% carbohydrate, of which glucose and galactose are constitutents. The outer membranes of this Acinetobacter thus differ in structure and composition from those of bacteria in the Enterobacteriaceae.
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PMID:Isolation of outer membranes with an ordered array of surface subunits from Acinetobacter. 412 37

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


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