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Journal of Bacteriology May 1979Deoxyribonucleic acid (DNA) from the covalently closed circular DNA molecules of Pseudomonas phage PM2 was found to enter normally transformable cells of Streptococcus... (Comparative Study)
Comparative Study
Deoxyribonucleic acid (DNA) from the covalently closed circular DNA molecules of Pseudomonas phage PM2 was found to enter normally transformable cells of Streptococcus pneumoniae as readily as linear bacterial DNA. In a mutant of S. pneumoniae that lacks a membrane nuclease and is defective in DNA entry, as many molecules of PM2 DNA as of linear DNA were bound on the outside of cells at equivalent DNA concentrations. Bound DNA suffered single-strand breaks, but circular DNA with preexisting breaks was bound no better than closed circles. In the presence of divalent cations, DNA bound to cells of a leaky nuclease mutant showed double-strand breaks. At least the majority of PM2 DNA that entered normal cells was single stranded. These results are consistent with a mechanism for DNA entry in which DNA is first nicked on binding, then a double-strand break is formed by cleavage of the complementary strand, and continued processive action of the membrane nuclease facilitates entry of the originally nicked strand. Although the bulk of circular donor DNA appeared to enter in this way, the results do not exclude entry of a small amount of donor DNA in an intact form.
Topics: Bacteriophages; Cell Membrane; DNA, Bacterial; DNA, Circular; DNA, Single-Stranded; DNA, Viral; Pseudomonas; Streptococcus pneumoniae; Transformation, Bacterial
PubMed: 35525
DOI: 10.1128/jb.138.2.404-409.1979 -
The Journal of Biological Chemistry Jan 1964
Topics: Chromatography; DNA; DNA, Bacterial; DNA-Directed DNA Polymerase; Electrophoresis; Escherichia coli; Metabolism; Nucleotidases; Phosphorus Isotopes; Research
PubMed: 14114848
DOI: No ID Found -
Journal of Bacteriology Jun 1969The buoyant density of deoxyribonucleic acid (DNA) from nine species and two varieties of Cryptococcus, three species and two varieties of Rhodotorula, and six species...
The buoyant density of deoxyribonucleic acid (DNA) from nine species and two varieties of Cryptococcus, three species and two varieties of Rhodotorula, and six species of Sporobolomyces was determined by CsCl density gradient equilibrium centrifugation. Several species were represented by two to four different strains. Expressed in moles per cent of guanine plus cytosine (GC content) the ranges were 49 to 65%, 52 to 70%, and 51 to 65% for Cryptococcus, Rhodotorula, and Sporobolomyces, respectively. For each genus, the GC content was distributed into two discrete groups with averages ranging from 52 to 54 and 60 to 66, respectively. An analysis of these results suggested that the determination of GC content of DNA had a taxonomic value for these yeast genera.
Topics: Centrifugation, Density Gradient; Cryptococcus; DNA; Densitometry; Mitosporic Fungi; Nucleotides
PubMed: 5815215
DOI: 10.1128/jb.98.3.1069-1072.1969 -
The Journal of Biological Chemistry Aug 1962
Topics: DNA; DNA-Directed RNA Polymerases; Endonucleases; RNA
PubMed: 13895983
DOI: No ID Found -
Journal of Bacteriology May 1975Insertion sequence (IS) regions have been identified previously as a cause of strongly polar mutations in Escherichia coli and several bacteriophages. The present...
Insertion sequence (IS) regions have been identified previously as a cause of strongly polar mutations in Escherichia coli and several bacteriophages. The present experiments indicate that genetically characterized IS regions occur on bacterial plasmid deoxyribonucleic acid (DNA) as both direct and inverted DNA sequence duplications. The DNA insertion which has been shown previously (Sharp et al., 1973) to control expression of tetracycline resistance in the R6-5 plasmid, and which occurs as directly and inversely repeated DNA sequences adjacent to the region believed to contain the tetracycline resistance gene, has been identified as IS3. A second genetically characterized insertion sequence (IS1) has been identified as a direct DNA duplication occurring at both junctions of the resistance transfer factor and R-determinant components of R6-5 and related plasmids. A model is presented for the reversible dissociation of resistance transfer factor and R-determinant components of co-integrate R plasmids at the sites of DNA sequence homology provided by the repeated IS regions.
Topics: Base Sequence; Centrifugation, Density Gradient; Chromosome Mapping; Coliphages; DNA Viruses; DNA, Bacterial; DNA, Circular; DNA, Viral; Drug Resistance, Microbial; Escherichia coli; Extrachromosomal Inheritance; Microscopy, Electron; Models, Biological; Mutation; Nucleic Acid Conformation; Tetracycline
PubMed: 1092669
DOI: 10.1128/jb.122.2.776-781.1975 -
Journal of Virology May 1968The synthesis of deoxyribonucleic acid (DNA) during in vivo infection of chick epithelium with fowlpox virus was examined by incorporation of tritiated thymidine into...
The synthesis of deoxyribonucleic acid (DNA) during in vivo infection of chick epithelium with fowlpox virus was examined by incorporation of tritiated thymidine into the acid-insoluble fraction. The proportion of precursor incorporated into host and viral DNA at various times after infection was determined by chromatography on columns of methylated albumin-kieselguhr. The first 60-hr period of infection was characterized by the synthesis of predominantly host DNA, the rate of production of which increased markedly over the control between 36 and 48 hr postinoculation (PI). Although the replication of viral DNA began between 12 and 24 hr PI, the rate of synthesis was very low during the first 60 hr. In contrast, an abrupt increase in the rate of viral DNA synthesis occurred between 60 and 72 hr PI, concomitantly with a sharp decline of host DNA synthesis. Subsequently, between 72 and 96 hr, the ratio of synthesis of viral DNA to host DNA progressively increased to a maximum of greater than 2:1. The temporal relationship of this biphasic pattern of host and viral DNA synthesis to hyperplasia and viral replication is discussed.
Topics: Albumins; Animals; Chromatography; DNA; DNA, Viral; Poultry Diseases; Poxviridae Infections; Thymidine; Tritium
PubMed: 4301312
DOI: 10.1128/JVI.2.5.421-429.1968 -
Molecular and Cellular Biology Mar 1981The structural organization of intracisternal A-particle genes has been studied, using isolates from a mouse gene library in lambda phage Charon 4A. The predominant gene...
The structural organization of intracisternal A-particle genes has been studied, using isolates from a mouse gene library in lambda phage Charon 4A. The predominant gene form among the isolates was 7.3 kilobases (kb) in length. R-loops between the 7-kb (35S) A-particle genomic ribonucleic acid and several of these genes were colinear, with no visible evidence of intervening deoxyribonucleic acid sequences. One recombinant was found with an A-particle gene that contained a 1.7-kb deletion. Using the deletion as a reference, the deoxyribonucleic acid and ribonucleic acid homology regions were localized with respect to one another and to the restriction map: the 5' terminus of the ribonucleic acid was several hundred base pairs within the 5' end of the deoxyribonucleic acid homology region. Restriction endonuclease fragments encompassing the 5' and 3' regions of one 7.3-kb gene were separately subcloned into pBR322. Heteroduplexes between the two subclones revealed an approximately 300-base pair segment of terminally redundant sequences. The cloned 3' fragment hybridized with restriction fragments from the 5' end of several other A-particle genes, demonstrating the presence of common (though not necessarily identical) terminally repeated sequences. A-particle genes varied in the occurrence of specific restriction sites at characteristic internal loci. However, heteroduplexes between several variant 7.3-kb genes showed continuous homology regions even when spread under stringent hybridization conditions. The relative abundance of restriction site variants was highly conserved in 12 laboratory strains of Mus musculus, in embryonic and adult tissues of a single inbred strain, and in the SC-1 cell line of feral mouse origin, but appeared to differ in a feral Japanese substrain, Mus musculus molossinus. Some evidence suggests that subsets of A-particle genes may have similar flanking sequences. The results are discussed in terms of the evolution of this multigene family.
Topics: Animals; Biological Evolution; Cell Line; Chromosome Mapping; DNA; Genes, Intracisternal A-Particle; Genes, Viral; Male; Mice; Mice, Inbred Strains; Multigene Family; Proto-Oncogenes; Repetitive Sequences, Nucleic Acid; Retroviridae
PubMed: 6821514
DOI: 10.1128/mcb.1.3.216-227.1981 -
The Journal of Biological Chemistry Jul 1958
Topics: DNA; Escherichia coli
PubMed: 13563462
DOI: No ID Found -
Journal of Bacteriology Jun 1963Sigal, Nicole (Laboratoire de Chimie Bactérienne du CNRS, Marseille, France), Jacques C. Senez, Jean Le Gall, and Madeleine Sebald. Base composition of the...
Sigal, Nicole (Laboratoire de Chimie Bactérienne du CNRS, Marseille, France), Jacques C. Senez, Jean Le Gall, and Madeleine Sebald. Base composition of the deoxyribonucleic acid of sulfate-reducing bacteria. J. Bacteriol. 85:1315-1318. 1963-The deoxyribonucleic acid constitution of several strains of sulfate-reducing bacteria has been analytically determined. The results of these studies show that this group of microorganisms includes at least four subgroups characterized by significantly different values of the adenine plus thymine to guanine plus cytosine ratio. The nonsporulated forms with polar flagellation, containing both cytochrome c(3) and desulfoviridin, are divided into two subgroups. One includes the fresh-water, nonhalophilic strains with base ratio from 0.54 to 0.59, and the other includes the halophilic or halotolerant strains with base ratio from 0.74 to 0.77. The sporulated, peritrichous strains without cytochrome and desulfoviridin ("nigrificans" and "orientis") are distinct from the above two types and differ from each other, having base ratios of 1.20 and 1.43, respectively.
Topics: Adenine; Base Composition; Chromatography; Cytochromes; Cytosine; DNA; DNA, Bacterial; Desulfovibrio; France; Guanine; Research; Spectrophotometry; Sulfates; Thymine
PubMed: 14047223
DOI: 10.1128/jb.85.6.1315-1318.1963 -
The Journal of Biological Chemistry Nov 1960
Topics: DNA; Deoxyadenine Nucleotides; Enzymes; Nucleosides; Nucleotides; Polymers; Thymidine Monophosphate
PubMed: 13747134
DOI: No ID Found