scholarly journals DURATION OF PREMEIOTIC DEOXYRIBONUCLEIC ACID SYNTHESIS AND THE STAGES OF PROPHASE I IN RABBIT OOCYTES

1970 ◽  
Vol 47 (3) ◽  
pp. 577-584 ◽  
Author(s):  
J. J. Kennelly ◽  
R. H. Foote ◽  
R. C. Jones
Keyword(s):  
Dna Synthesis ◽  
Meiotic Prophase ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Acid Synthesis ◽  
Prophase I ◽  
Meiotic Prophase I ◽  
Maximum Duration ◽  
Deoxyribonucleic Acid Synthesis ◽  
Silver Grains

To estimate the duration of oocyte DNA synthesis 36, 3-day-old female rabbits received 3, 6, 9, 12, 15, or 18 injections of tritiated thymidine (thy-3H) at hourly intervals. The ovaries, removed at 1, 10, or 20 days after the first injection, were radioautographed. Counts made of the number of silver grains associated with oocyte nuclei in meiotic Prophase I indicate that the duration of DNA synthesis is between 9 and 12 hr. To determine the length of the stages of meiotic Prophase I, a group of 2-3-day-old rabbits was given a single sub-cutaneous injection of thy-3H, and the ovaries were removed at hourly and/or daily intervals after treatment. The minimum duration of leptotene was 3 hr and the maximum duration probably was less than 8 hr. The maximum durations of zygotene, pachytene, and diplotene were estimated to be 44, 216, and 96 hr, respectively. The interval from the end of oogonial DNA synthesis to the beginning ofpremeiotic DNA synthesis (G2 + Mitosis + G1) appeared to be less than 6 hr.

scholarly journals Ornithine decarboxylase activity and the onset of deoxyribonucleic acid synthesis in regenerating liver

1978 ◽  
Vol 170 (1) ◽  
pp. 123-127 ◽  
Author(s):  
J A McGowan ◽  
N Fausto
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Time Course ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Low Protein ◽  
Deoxyribonucleic Acid Synthesis ◽  
Second Peak

Compared with normally fed animals, rats fed on a low-protein diet for 3 days exhibit a considerable delay in DNA synthesis after partial hepatectomy. In the regenerating livers of these animals (a) the timing of the first peak of ornithine decarboxylase activity is not altered and (b) the second peak of enzyme activity is delayed by a few hours, but polyamine concentrations are similar to those of normally fed rats. The results suggest that regardless of the possible effect of polyamines on DNA synthesis, the time course of ornithine decarboxylase activity appears to be independent of the onset of DNA replication in regenerating livers.

Duration of Availability of Tritiated Thymidine Following Intraperitoneal Injection

1968 ◽  
Vol 3 (1) ◽  
pp. 89-93
Author(s):  
W. K. BLENKINSOPP
Keyword(s):  
Cell Division ◽  
Intraperitoneal Injection ◽  
Deoxyribonucleic Acid ◽  
Direct Evidence ◽  
Tritiated Thymidine ◽  
Indirect Evidence ◽  
Acid Synthesis ◽  
Single Intraperitoneal Injection ◽  
Deoxyribonucleic Acid Synthesis

Much indirect evidence supports the assumption that tritiated thymidine does not label cells which enter the deoxyribonucleic acid synthesis phase (S) more than 1 h after injection. Direct evidence confirming this assumption was obtained by counting labelled epithelial nuclei in mice killed 1, 4 or 6 h after a single intraperitoneal injection of [3H]thymidine; colchicine was used to prevent the increase in number of labelled nuclei which would otherwise have occurred because of cell division. The proportion of cells labelled was the same at 1 h as at 4 or 6 h after injection of [3H]thymidine. Nuclei were regarded as labelled if they were overlaid by 4 grains or more; comparison of nuclear and background labelling indicated that nuclei overlaid by 3 grains or less represented background labelling.

scholarly journals Effect of drugs on deoxyribonucleic acid synthesis in isolated mammalian cell nuclei. Comparison with partially purified deoxyribonucleic acid polymerases

1979 ◽  
Vol 178 (3) ◽  
pp. 621-626 ◽  
Author(s):  
J F Burke ◽  
P M Duff ◽  
C K Pearson
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Cell Nuclei ◽  
Isolated Nuclei ◽  
Dna Polymerase Alpha ◽  
Polymerase Beta ◽  
Deoxyribonucleic Acid Synthesis

In order to ascertain the identity of the DNA-dependent DNA polymerase responsible for the observed DNA synthesis in nuclei isolated from baby-hamster kidney (BHK-21/C13) cells a comparative study was carried out on the effects of some drugs, reported to influence DNA synthesis, on DNA synthesis catalysed by these nuclei and by partially purified DNA polymerase-alpha and -beta. In all cases DNA synthesis by isolated nuclei and polymerase-alpha was inhibited to similar extents by N-ethylmaleimide, p-hydroxymercuribenzoate, novobiocin, heparin and phosphonoacetic acid; polymerase-beta was much less affected by these compounds. Ethidium bromide inhibited all DNA synthesis to similar extents, although at low concentrations (about 2 microgram/ml) synthesis in isolated nuclei was stimulated. The results are discussed in relation to the proposal that DNA polymerase-alpha catalyses the covalent extension of Okazaki fragments that these nuclei carry out in vitro.

scholarly journals Deoxyribonucleic acid synthesis in mammalian nuclei. Incorporation of deoxyribonucleotides and chain-terminating nucleotide analogues

1971 ◽  
Vol 121 (5) ◽  
pp. 803-809 ◽  
Author(s):  
M. A. Waqar ◽  
L. A. Burgoyne ◽  
M. R. Atkinson
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis ◽  
Dna Chain ◽  
Relationship Of ◽  
The Relationship ◽  
Neighbour Analysis

The properties of a nuclear preparation from rat liver and thymus are described. (1) Nearest-neighbour analysis after incorporation of 32P-labelled nucleotide residues from dATP, dCTP, dGTP, dTTP and arabinofuranosyl analogues of CTP and ATP shows template-dependent DNA synthesis. (2) Where primer termini are limiting, incorporation of arabinofuranosyl analogues of AMP and CMP residues proceeds to a limit indicating that both of these analogues are DNA chain terminators. (3) No large differences have been found between the priming potentialities or the intrinsic DNA polymerase activities of nuclei from resting or regenerating liver and the relationship of this DNA synthesis in vitro to DNA replication or repair in vivo is briefly discussed.

USE OF I125-LABELED 5-IODO-2′-DEOXYURIDINE FOR THE MEASUREMENT OF DNA SYNTHESIS IN MAMMALIAN CELLS IN VITRO

1963 ◽  
Vol 41 (11) ◽  
pp. 2343-2351 ◽  
Author(s):  
S. Mak ◽  
J. E. Till
Keyword(s):  
Dna Synthesis ◽  
Mammalian Cells ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
X Rays ◽  
Beta Particles ◽  
Deoxyribonucleic Acid Synthesis ◽  
Gamma Emitter

The use of isotopically labeled 5-iodo-2′-deoxyuridine (I125UdR) for determination of the rate of deoxyribonucleic acid synthesis in mammalian cells in vitro has been investigated. The results obtained indicate that for this purpose I125UdR is a suitable substitute for the more commonly used DNA precursor, tritium-labeled thymidine (H3TdR). I125UdR appears to be incorporated specifically into the DNA of cells in culture, and has been demonstrated to compete with H3TdR, although the Km for H3TdR was smaller than that of I125UdR by a factor of approximately 4. The amount of label incorporated into DNA of cells increased linearly with time. When the rate of DNA synthesis was reduced by exposure of the cells to various doses of X-rays, the ratio of I125UdR incorporation to H3TdR incorporation into DNA of cells was found to be a constant, which supports the view that uptake of the analogue provides as reliable an indication of effects upon the rate of DNA synthesis as does that of H3TdR. The chief advantage of I125UdR over H3TdR is that I125 is a gamma emitter, so that the difficulties encountered in detection of the low energy beta particles from H3 may be avoided.

scholarly journals TRANSIENT PHOSPHORYLATION OF DEOXYRIBOSIDES AND REGULATION OF DEOXYRIBONUCLEIC ACID SYNTHESIS

1961 ◽  
Vol 11 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Yasuo Hotta ◽  
Herbert Stern
Keyword(s):  
Dna Synthesis ◽  
Enzyme Induction ◽  
Deoxyribonucleic Acid ◽  
Lilium Longiflorum ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis ◽  
Patterns Of Behavior

Microspores isolated from Lilium longiflorum and Trillium erectum were studied with respect to their capacities for phosphorylating deoxyribosides in vitro. It was found that such capacities are manifest only during brief intervals of time adjacent to periods of DNA synthesis, and that none of the neighboring cells in the anther acquire them. The observed patterns of behavior are interpreted in terms of enzyme induction as a device for regulating DNA synthesis.

Cell Proliferation in the Epithelium of the Oesophagus, Trachea and Ureter in Mice

1969 ◽  
Vol 5 (2) ◽  
pp. 393-401
Author(s):  
W. K. BLENKINSOPP
Keyword(s):  
Cell Cycle ◽  
Deoxyribonucleic Acid ◽  
Single Injection ◽  
Tritiated Thymidine ◽  
Acid Synthesis ◽  
Basal Cells ◽  
Paraffin Sections ◽  
Cell Cycle Time ◽  
Deoxyribonucleic Acid Synthesis ◽  
Intermediate Cells

Over a 24-h period, groups of mice were given a single injection of colchicine (to collect blocked metaphases) and tritiated thymidine (to label nuclei synthesizing deoxyribonucleic acid). Epithelial nuclei in the oesophagus, trachea and ureter were examined and counted in paraffin sections: the duration of deoxyribonucleic acid synthesis (Ts) was calculated from the numbers of blocked metaphases and labelled nuclei, the duration of the post-synthetic gap (TG2) was estimated from the proportion of blocked mataphases labelled, and the cell cycle time (Tc) was calculated from Ts and the proportion of nuclei labelled. In each epithelium the different layers seen by light microscopy were analysed separately. Ts was probably the same for the basal and superficial cells in the trachea (about 8 h), and was probably the same for the basal, intermediate and superficial cells in the ureter (about 5 h). In the oesophagus Ts was 8.5 h. TG2 was probably the same for the basal and superficial cells in the trachea (3.6 h), and probably the same for the basal, intermediate and superficial cells in the ureter (about 4.6 h). In the oesophagus TG2 was 2.8 h. Tc was about 380 h (basal cells) and 1400 h (superficial cells) in the trachea, and about 8000 h (basal and intermediate cells) and 2700 h (superficial cells) in the ureter. In the oesophagus Tc was 41 h.

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