scholarly journals Deoxyribonucleic Acid Synthesis in Relation to Duplication of Centers in Dividing Eggs of the Sea Urchin, Strongylocentrotus purpuratus

1960 ◽  
Vol 7 (4) ◽  
pp. 651-655 ◽  
Author(s):  
Nancy L. R. Bucher ◽  
Daniel Mazia
Keyword(s):  
Dna Synthesis ◽  
Sea Urchin ◽  
Deoxyribonucleic Acid ◽  
Strongylocentrotus Purpuratus ◽  
Acid Synthesis ◽  
Blocking Agent ◽  
Deoxyribonucleic Acid Synthesis ◽  
Reproductive Events ◽  
Prior Event

The earliest known event in the sequence leading to mitosis is the duplication of cell centers. The present investigation shows that the synthesis of DNA, although closely following it in time, is initiated entirely independently of this prior event. Fertilized eggs of the sea urchin, S. purpuratus, were exposed to ß-mercaptoethanol at intervals during development. This substance, when introduced at appropriate times, blocks mitosis and also prevents duplication of centers. Whether or not duplication of centers had already occurred before introduction of the blocking agent was determined by observing the division patterns of eggs after the mercaptoethanol was removed: division of one cell into two, or of two into four indicated that duplication had not occurred; division of one into four or of two into eight, that it had. Incorporation of H3-labeled thymidine into DNA, as demonstrated by autoradiography, showed that DNA synthesis took place during the mercaptoethanol block regardless of whether or not the centers had already duplicated. Thus the two major reproductive events of the mitotic sequence, although normally coordinated in time, can be dissociated experimentally and shown to function independently.

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.

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.

Nuclear Ultrastructure of the Transforming Lymphocyte during Inhibition of Deoxyribonucleic Acid Synthesis with Hydroxyurea

1969 ◽  
Vol 4 (3) ◽  
pp. 583-591
Author(s):  
GILLIAN R. MILNER
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Metabolic Inhibition ◽  
Nuclear Ultrastructure ◽  
Deoxyribonucleic Acid Synthesis ◽  
Inhibition Of Dna Synthesis

The pattern of decondensation of heterochromatin in the transforming lymphocyte was found to be unaffected by hydroxyurea although DNA synthesis, which normally accompanies the latter part of this decondensation, was greArticleTitley inhibited. It is suggested that metabolic inhibition of DNA synthesis may result in atypical sites of DNA synthesis when the inhibitor is removed, since such sites are normally partly governed by an ordered sequence of decondensation of heterochromatin.

scholarly journals Ornithine decarboxylase and polyamines in liver and kidneys of rats on cyclical regimen of protein-free and protein-containing diets. Relationship to deoxyribonucleic acid synthesis in liver

1977 ◽  
Vol 168 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Donald C. Farwell ◽  
Jose B. Miguez ◽  
Edward J. Herbst
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Multiple Injections ◽  
Deoxyribonucleic Acid Synthesis ◽  
Cyclical Regimen ◽  
Protein Free Diet ◽  
Fold Stimulation ◽  
Stimulation Of

1. The activity of ornithine decarboxylase in the liver and kidneys of rats maintained on a cyclical regimen of protein-free and protein-containing diets was investigated. There was a daily activation of the enzyme in response to the feeding of protein after 3 days feeding of protein-free diet. 2. The activation of ornithine decarboxylase in the liver and kidneys of rats re-fed on protein was demonstrable throughout 16 cycles of alternating 3-day periods of protein-free and protein-containing diets. The magnitude of the activation in the kidneys diminished from 20-fold stimulation in the first cycle to 5-fold stimulation (compared with animals fed with protein-free diet) in the later cycles of protein re-feeding. The activation of the enzyme in liver was decreased from 20-fold stimulation in the first cycle to approx. 10-fold stimulation in later cycles. 3. The concentration of spermidine was increased by approx. 50% in the liver of animals during cycling from protein-free to protein-containing diets. Spermine was unchanged, and putrescine was maintained at a low concentration approx. one-fifth to one-tenth that of spermidine after protein re-feeding. 4. The incorporation of [3H]thymidine into liver DNA was increased 10-fold in animals re-fed with protein compared with animals receiving protein-free diets. 5. The activation of ornithine decarboxylase by re-feeding of protein was inhibited 90% by the injection of propane-1,3-diamine during re-feeding. The stimulation of DNA synthesis was inhibited 60% by multiple injections of propane-1,3-diamine during the re-feeding of protein.

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

1963 ◽  
Vol 41 (1) ◽  
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 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.

Effects of (+)-Octanoylcarnitine on Deoxyribonucleic Acid Synthesis in Regenerating Rabbit Liver

1982 ◽  
Vol 62 (3) ◽  
pp. 295-297 ◽  
Author(s):  
Toshio Nakatani ◽  
Kazuhiro Yasuda ◽  
Kazue Ozawa ◽  
Sadao Kawashima ◽  
Takayoshi Tobe
Keyword(s):  
Fatty Acid ◽  
Dna Synthesis ◽  
Fatty Acid Oxidation ◽  
Deoxyribonucleic Acid ◽  
Energy Charge ◽  
Acid Synthesis ◽  
Hepatic Regeneration ◽  
Acid Oxidation ◽  
Remnant Liver ◽  
Deoxyribonucleic Acid Synthesis

1. (+)-Octanoylcarnitine, a potent inhibitor of fatty acid oxidation, was infused intraportally into rabbits after 70% hepatectomy, and its effects on the rate of deoxyribonucleic acid (DNA) synthesis were examined. 2. The rate of DNA synthesis was markedly enhanced 48 h after hepatectomy. At this time, synthesis was decreased significantly by (+)-octanoylcarnitine. 3. It is suggested that fatty acid oxidation contributes to enhanced hepatic regeneration by elevating the decreased energy charge level [(ATP + 0.5ADP)/(ATP + ADP + AMP)] of the remnant liver.

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