INCORPORATION OF RADIOACTIVE PURINE AND PYRIMIDINE BASES AND OF THYMIDINE INTO THE DEOXYRIBONUCLEIC ACID OF SALMON MILTS

1964 ◽  
Vol 42 (1) ◽  
pp. 51-57 ◽  
Author(s):  
H. L. A. Tarr
Keyword(s):  
Orotic Acid ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Experimental Conditions ◽  
Live Fish ◽  
Pyrimidine Bases

C14-labeled adenine, guanine and cytosine, and tritiated thymidine were incorporated into the deoxyribonucleic acid of salmon milts, either by injection into the milts of live fish or into excised milts. The amount incorporated was very small. Under the experimental conditions radioactive nucleosides, deoxyuridine, adenosine 5′-mono- and tri-phosphates, orotic acid, uracil, ribose 1-phosphate, and ribose 5-phosphate were not incorporated. It is suggested that these results may be due to the comparative impermeability of the cells to the various compounds.

FORMATION OF PURINE AND PYRIMIDINE NUCLEOSIDES, DEOXYNUCLEOSIDES, AND THE CORRESPONDING MONONUCLEOTIDES BY SALMON MILT EXTRACT NUCLEOSIDE PHOSPHORYLASE AND NUCLEOSIDE KINASE ENZYMES

1964 ◽  
Vol 42 (11) ◽  
pp. 1535-1545 ◽  
Author(s):  
H. L. A. Tarr
Keyword(s):  
Orotic Acid ◽  
Salmo Gairdneri ◽  
Cell Free Extract ◽  
Experimental Conditions ◽  
Nucleoside Phosphorylase ◽  
Pyrimidine Nucleosides ◽  
Enzyme Substrate ◽  
A Cell ◽  
Pyrimidine Bases

A cell-free extract of immature Salmo gairdneri milts possessed both nucleoside and deoxynucleoside phosphorylase activities. Formation of guanosine, deoxyguanosine, uridine, deoxyuridine, thymidine, thymine riboside, inosine, and deoxycytidine from the corresponding purine or pyrimidine bases was very marked, and the formation of deoxyinosine and cytidine generally was less pronounced, under the experimental conditions. The extract also possessed nucleoside phosphokinase and deoxynucleoside phosphokinase activities, although these were considerably less marked than the former. Formation of the mononucleotides of adenosine, uridine, thymidine, deoxyuridine, guanosine, inosine, and deoxyinosine in the presence of adenosinetriphosphate was recorded. When orotic acid was employed as enzyme substrate, uridine, deoxyuridine, and uridylic acid were formed. Comparatively feeble formation of cytidylic and deoxycytidylic acids from the corresponding nucleosides was found. The possible significance of these findings, in relation to known routes of biosynthesis of mononucleotides, is discussed.

EFFECTS OF A GLUCOCORTICOID (DEXAMETHASONE) ON THE EOSINOPHILS OF THE RAT

1967 ◽  
Vol 37 (4) ◽  
pp. 463-469 ◽  
Author(s):  
EVELYN C. BLENKINSOPP ◽  
W. K. BLENKINSOPP
Keyword(s):  
Continuous Infusion ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Blood Eosinophil ◽  
Consequent Reduction ◽  
Reticulo Endothelial System ◽  
Eosinophil Counts

SUMMARY The effects of single and continuous administrations of a synthetic gluco-corticoid (dexamethasone) on eosinophil numbers and distribution have been studied. Absolute blood eosinophil counts were made, and the turnover of the eosinophils was examined by continuous infusion of tritiated thymidine to label the deoxyribonucleic acid of all newly formed cells. Dexamethasone equivalent to less than 200 μg. cortisone/100 g. rat/day produced disappearance of eosinophils from the blood and the normal output of glucocorticoids is therefore probably less than this. Single administrations of dexamethasone produced a blood eosinopenia within 2 hr. due to removal and destruction of eosinophils by the reticulo-endothelial system. Continuous dexamethasone administration reduced the number of proliferating eosinophil cells in the marrow, with a consequent reduction in the number of eosinophils in the tissues.

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.

An Effect of Tritiated Thymidine on the Incorporation of Thymidine into Chromosomal Deoxyribonucleic Acid

Nature ◽  
1960 ◽  
Vol 188 (4749) ◽  
pp. 511-512 ◽  
Author(s):  
MARGARIDA KRAUSE ◽  
W. PLAUT
Keyword(s):  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine

X-Ray-Induced Incorporation of Tritiated Thymidine into Deoxyribonucleic Acid of Grasshopper Neuroblast Chromosomes

1963 ◽  
Vol 19 (3) ◽  
pp. 526 ◽  
Author(s):  
Richard A. McGrath
Keyword(s):  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
X Ray

FORMATION OF RIBOMONONUCLEOTIDES FROM PURINE AND PYRIMIDINE BASES AND 5′-PHOSPHORIBOSYLPYROPHOSPHATE BY A SALMON MILT EXTRACT

1964 ◽  
Vol 42 (5) ◽  
pp. 575-581 ◽  
Author(s):  
H. L. A. Tarr
Keyword(s):  
Lithium Chloride ◽  
Chloride Solution ◽  
Orotic Acid ◽  
Sockeye Salmon ◽  
Radioactive Tracer ◽  
Tracer Technique ◽  
Radioactive Tracer Technique ◽  
Lithium Chloride Solution ◽  
Pyrimidine Bases

Soluble extracts of immature sockeye salmon milts were prepared by blending them with 0.66 M lithium chloride solution to effect plasmolysis, followed by dilution to 0.10 M concentration with water and removal of the precipitated nucleoprotamine by centrifuging. By means of radioactive tracer technique it was shown that these extracts phosphorylated adenine, guanine, hypoxanthine, thymine, uracil, cytosine, and orotic acid in the presence of α-phosphoribosylpyrophosphate to yield ribomononucleotides.

scholarly journals Effect of denervation on the synthesis of ribonucleic acid and deoxyribonucleic acid in rat diaphragm muscle

1968 ◽  
Vol 108 (2) ◽  
pp. 177-183 ◽  
Author(s):  
K L Manchester ◽  
E J Harris
Keyword(s):  
Nucleic Acids ◽  
Ribonucleic Acid ◽  
Orotic Acid ◽  
Deoxyribonucleic Acid ◽  
Diaphragm Muscle ◽  
Unit Mass ◽  
Rat Diaphragm ◽  
The Third

1. The effect of unilateral denervation of rat diaphragm muscle on its content of nucleic acids and their incorporation of precursors was investigated. 2. After denervation the paralysed hemidiaphragm hypertrophies and within 3 days its content of RNA increases considerably. The concentration of DNA/unit mass remains fairly constant. 3. During this period there is some increase in the rate of incorporation of [14C]adenine into RNA, whereas there is some diminution in the rate of incorporation of [14C]orotic acid. 4. Incorporation of [14C]adenine and [3H]thymidine into DNA is much increased in the paralysed tissue, reaching its maximum by about the third day, but returning to normal by the tenth. 5. The significance of these results in relation to the hypertrophy after denervation is discussed.

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