scholarly journals Deoxyribonucleic acid synthesis in mammalian systems. Permealysed Ehrlich ascites cells in vitro first label Okazaki-type low-molecular-weight deoxyribonucleic acid and then high-molecular-weight deoxyribonucleic acid

1972 ◽  
Vol 130 (4) ◽  
pp. 959-964 ◽  
Author(s):  
Leigh A. Burgoyne
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Preparation Procedure ◽  
Low Molecular Weight ◽  
Deoxyribonucleic Acid Synthesis ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells

During the evaluation of a method of preparing permealysed Ehrlich ascites cells, shortterm labelling experiments were carried out with d[3H]TTP. In the first minute the bulk of the label appeared as low-molecular-weight pieces of DNA. Subsequently the label appeared in DNA of much higher molecular weight. A brief description of the preparation procedure and the properties of the product is provided. Evidence is presented to show that the nucleotide was incorporated directly without intermediate conversion into dTMP or thymidine.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

Nonrandom substitution of 2-aminopurine for adenine during deoxyribonucleic acid synthesis in vitro

Biochemistry ◽  
1981 ◽  
Vol 20 (21) ◽  
pp. 6235-6244 ◽  
Author(s):  
Reynaldo C. Pless ◽  
Lore M. Levitt ◽  
Maurice J. Bessman
Keyword(s):  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis

scholarly journals Deoxyribonucleic acid polymerases of Euglena gracilis. Purification and properties of two distinct deoxyribonucleic acid polymerases of high molecular weight

1975 ◽  
Vol 151 (2) ◽  
pp. 227-238 ◽  
Author(s):  
A G McLennan ◽  
H M Keir
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Euglena Gracilis ◽  
Deoxyribonucleic Acid ◽  
Deae Cellulose ◽  
Low Molecular Weight ◽  
Optimum Conditions ◽  
Electrophoretic Mobilities ◽  
Substrate Activation ◽  
Purification And Properties

Two DNA polymerases of high molecular weight, pol A (mol.wt. 190 000) and pol B (mol.wt. 240 ooo), have been purified 6300-fold and 1600-fold respectively from an extramitochondrial supernatant of a bleached strain of Euglena gracilis. They have very similar requirements when assayed with an ‘activated’-DNA primer-template [the optimum conditions of pH and ionic (K+ and Mn2+) composition being 7.2, 25 mM and 0.2 mM respectively]. 0.2 mM-Mn2+ was about 1.5-2-fold as effective as 2 mM-Mg2+, owing to substrate activation by deoxyribonucleoside 5′-triphosphates in the presence of Mn2+. Km values for the triphosphates in the absence of activation were about 10(-6)M with Mn2+ and 8 × 10(-6) M with Mg2+ for both enzymes. They were inhibited to the same extent by N-ethylmaleimide, novobiocin and o-phenanthroline, but differed in their chromatographic behaviour on DEAE-cellulose and in their electrophoretic mobilities on polyacrylamide gel. No evidence was found for the existence in these cells of a DNA polymerase of low molecular weight, but there were indications that a third enzyme of high molecular weight might exist.

FRACTIONATION OF LIVER SOMATOMEDIN ACTIVITY BY ULTRAFILTRATION

1974 ◽  
Vol 62 (2) ◽  
pp. 355-361 ◽  
Author(s):  
JENNIFER M. DEHNEL ◽  
P. D. McCONAGHEY ◽  
M. J. O. FRANCIS
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Cartilage Growth ◽  
The Relationship ◽  
Somatomedin Inhibitors

SUMMARY Plasma somatomedin is the intermediary through which growth hormone (GH) exerts its effects on the growing skeleton. Somatomedin activity may be produced in vitro by perfusion of the liver and kidneys of rats with Waymouth's medium containing GH. The relationship between the activity of plasma somatomedin and somatomedin of hepatic and renal origin has yet to be clarified. Somatomedin from plasma can be separated into active fractions of both high and low molecular weight. Similarly, ultrafiltration of medium containing somatomedin of hepatic origin indicates the existence of two active fractions, one of high molecular weight (greater than 50000) and one of low molecular weight (less than 1000). The latter can be attributed to the release of amino acids, such as serine and glutamine, by the perfused tissue. The high molecular weight fraction is believed to represent GH-dependent somatomedin. Fractions that inhibit production of cartilage matrix are present in liver perfusates as well as in plasma. These results provide further evidence that the liver is a source of GH-dependent somatomedin in vivo. Furthermore, cartilage growth may be controlled not only by the GH-stimulated release of somatomedin by the liver, but also by its release of acid-labile somatomedin inhibitors.

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.

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