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Journal of Virology Sep 1972Polyoma-transformed cells can revert in the properties characteristic of transformation, although they maintain the polyoma-specific T antigen. Transformed cells contain...
Polyoma-transformed cells can revert in the properties characteristic of transformation, although they maintain the polyoma-specific T antigen. Transformed cells contain the same number of copies of polyoma virus deoxyribonucleic acid (DNA) per cell (eight) as revertants with a subdiploid or a subtetraploid chromosome number. The results indicate that the duplication of chromosomes in the subtetraploid revertants did not include the chromosomes that carry the viral genome. The virus DNA in both transformed and revertant cells was associated with high-molecular-weight cell DNA. Reversion of the properties of transformed cells was, therefore, not associated either with a decrease in number of virus DNA copies per cell or with a lack of association of the virus DNA with cell DNA.
Topics: Animals; Cell Transformation, Neoplastic; Cells, Cultured; Centrifugation, Density Gradient; Cricetinae; DNA; DNA, Neoplasm; DNA, Viral; Diploidy; Genetic Variation; Nucleic Acid Hybridization; Phosphorus Isotopes; Polyomavirus; Polyploidy; RNA, Viral; Tritium
PubMed: 4342053
DOI: 10.1128/JVI.10.3.456-461.1972 -
The Biochemical Journal Feb 1972A method is given for small-scale preparation of DNA from 1.0-1.5g of adult rat tissues. The product from brain or liver is characterized by base ratios and phosphorus...
A method is given for small-scale preparation of DNA from 1.0-1.5g of adult rat tissues. The product from brain or liver is characterized by base ratios and phosphorus content which accord with reported values for rat tissue. It is reasonably free of RNA, protein and glycogen. It contains 5-hydroxymethylcytosine at a content of about 15% of the total cytosine bases present. 5-Hydroxymethylcytosine is also demonstrable in mouse and frog brain DNA and in the crude cytidylic acid fractions obtained from RNA hydrolysates of rat brain and liver. 5-Hydroxymethylcytosine is identified by paper chromatography, u.v. spectra in acid and alkaline solutions and by its conversion into 5-hydroxymethyluracil.
Topics: Animals; Anura; Brain Chemistry; Chromatography, Paper; Cytosine; Cytosine Nucleotides; DNA; Liver; Mice; RNA; Rana catesbeiana; Rats; Ultraviolet Rays; Uracil
PubMed: 4538516
DOI: 10.1042/bj1260781 -
Journal of Bacteriology Jan 1977The structural gene for ampicillin resistance resides upon a 3.2 X 10(6)-dalton sequence of deoxyribonucleic acid, TnA that can be transposed from replicon to replicon...
The structural gene for ampicillin resistance resides upon a 3.2 X 10(6)-dalton sequence of deoxyribonucleic acid, TnA that can be transposed from replicon to replicon in laboratory experiments. TnA was transposed from a large conjugative plasmid to a small nonconjugative plasmid, RSF1010. Several RSF1010::TnA plasmids isolated in these laboratory experiments have been shown to be identical to plasmids found in clinical isolates. These data provide direct support to the theory that transposition of drug resistance genes play a key role in the evolution of R plasmids.
Topics: Ampicillin; Conjugation, Genetic; DNA, Bacterial; DNA, Circular; DNA, Recombinant; Enterobacteriaceae; Penicillin Resistance; R Factors; Recombination, Genetic
PubMed: 583751
DOI: 10.1128/jb.129.1.530-533.1977 -
Journal of Anatomy Jun 1967
Topics: Aged; Cell Nucleus; DNA; Densitometry; Diploidy; Humans; Infant, Newborn; Karyometry; Liver; Polyploidy
PubMed: 6051729
DOI: No ID Found -
Journal of Dairy Science Jan 1983Guinea pigs were killed on day 5 of lactation. Each of lactations one through six was represented by six animals. Body weight was measured, and mammary glands were...
Guinea pigs were killed on day 5 of lactation. Each of lactations one through six was represented by six animals. Body weight was measured, and mammary glands were removed. Wet weight of mammary gland, dry weight of fat-free tissue, and weight and percent (relative to dry fat-free tissue) of deoxyribonucleic acid, ribonucleic acid, and hydroxyproline were measured. Collagen and noncollagenous dry fat-free tissues were estimated. Body weight increased from 800 g in first lactation to 1035 g in fifth and 975 g in sixth lactation. Mammary wet weight increased quadratically from 20 g for first lactation to 31 g for fifth and 26 g for sixth lactation. Dry fat-free tissue followed a similar pattern, increasing from 2330 mg first lactation to 3647 mg fifth and 3242 mg sixth lactation. Deoxyribonucleic acid rose linearly from 70 mg first lactation to 121 mg fifth and 110 sixth lactation. Ribonucleic acid followed a similar pattern, increasing from 182 mg first lactation to 289 mg sixth lactation. Ratio of ribonucleic acid to deoxyribonucleic acid was constant at 2.2. Amount of collagen was also constant at 257 mg. However, percent collagen decreased linearly from 12% first lactation to 7.1% sixth lactation. Mammary gland increases in size over subsequent lactations to five and then decreases slightly. The increase is not of connective tissue or stroma, as measured by hydroxyproline, but is an increase in parenchyma or cells involved with milk secretion and harvest.
Topics: Animals; Body Weight; DNA; Female; Guinea Pigs; Lactation; Mammary Glands, Animal; Organ Size; Pregnancy
PubMed: 6833592
DOI: 10.3168/jds.S0022-0302(83)81749-4 -
The Journal of Biological Chemistry Dec 1962
Topics: DNA; Ligases; Purines; Pyrimidines; RNA
PubMed: 13958267
DOI: No ID Found -
Journal of Clinical Pathology Sep 1964Values for the deoxyribonucleic acid and ribonucleic acid contents in a considerable number of human post-mortem tissues are given and briefly discussed.
Values for the deoxyribonucleic acid and ribonucleic acid contents in a considerable number of human post-mortem tissues are given and briefly discussed.
Topics: Autopsy; Cadaver; DNA; Histocytochemistry; RNA; Rats; Research
PubMed: 14207791
DOI: 10.1136/jcp.17.5.554 -
Journal of Bacteriology Mar 1974The circular deoxyribonucleic acid (DNA) of Bacillus megaterium was fractionated by sedimentation velocity on preparative zonal gradients. The fractions obtained were...
The circular deoxyribonucleic acid (DNA) of Bacillus megaterium was fractionated by sedimentation velocity on preparative zonal gradients. The fractions obtained were characterized by analytical sedimentation velocity analysis on neutral and alkaline sucrose gradients, and by contour length measurement by electron microscopy. Each fraction was found to contain circular molecules of one to three discrete sizes, in various combinations of covalently closed and open circular forms. Estimations of the molecular masses of these sizes gave values of 3.9, 6.2, 16.0, 31, and 60 million daltons for the major molecular species. Minor amounts of molecules of 7.6, 11.7, 47, 89, and 112 million daltons were observed in the electron microscope analyses. Length measurements of almost 600 molecules from the various fractions showed that all except six could be placed in distinct size classes. The distribution of molecular sizes in unfractionated circular DNA was shown to consist primarily of the two smallest size classes, although the relative proportions by weight of five of the classes were roughly equivalent.
Topics: Bacillus megaterium; Carbon Radioisotopes; Centrifugation, Density Gradient; DNA, Bacterial; DNA, Circular; Drug Resistance, Microbial; Microscopy, Electron; Molecular Weight; Mutation; Streptomycin; Thymidine; Thymine; Tritium
PubMed: 4205193
DOI: 10.1128/jb.117.3.1201-1209.1974 -
Proceedings of the National Academy of... Jul 1961
Topics: DNA; Pressure; Tobacco Mosaic Virus; Viruses
PubMed: 13712604
DOI: 10.1073/pnas.47.7.1015 -
Journal of Bacteriology Sep 1977The synthesis of killer double-stranded ribonucleic acid (dsRNA) in Saccharomyces cerevisiae was examined in seven different cell division cycle mutants (cdc) that are... (Comparative Study)
Comparative Study
The synthesis of killer double-stranded ribonucleic acid (dsRNA) in Saccharomyces cerevisiae was examined in seven different cell division cycle mutants (cdc) that are defective in nuclear deoxyribonucleic acid replication and contain the "killer character." In cdc28, cdc4, and cdc7, which are defective in the initiation of nuclear deoxyribonucleic acid synthesis, and in cdc23 or in cdc14, defective in medial or late nuclear division, an overproduction of dsRNA at the restrictive temperature was observed. In contrast to the above mutants, the synthesis of killer dsRNA is not enhanced at the restrictive temperature in either cdc8 or cdc21, which are defective in deoxyribonucleic acid chain elongation. Examination of killer sensitive strains (cdc7 K- and cdc4 K-) has shown that the complete killer dsRNA genome is essential for the overproduction of dsRNA at the restrictive temperature.
Topics: Cell Division; Cell Nucleus; DNA; Genes; Mutation; Mycotoxins; Phenotype; RNA; Saccharomyces cerevisiae; Temperature
PubMed: 330495
DOI: 10.1128/jb.131.3.735-740.1977