EFFECT OF X-IRRADIATION ON DNA SYNTHESIS IN EHRLICH ASCITES CARCINOMA CELLS

1965 ◽  
Vol 43 (7) ◽  
pp. 859-864 ◽  
Author(s):  
Shan-Ching Sung
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Total Rna ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells ◽  
X Irradiation

The rate of DNA synthesis in Ehrlich ascites cells measured immediately after X-irradiation of 500 r for 6 minutes in vitro showed about 15% reduction. However, if X-irradiation was followed by preincubation of the cells, the subsequent synthesis of DNA in the X-irradiated cells was markedly inhibited. Under the same condition, the uptake of thymidine-2-C14, uridine-2-C14, adenine-8-C14, and glycine-1-C14, and protein synthesis in the X-irradiated cells were found to be almost the same as those in the non-irradiated control. RNA synthesis measured as total RNA was only slightly inhibited.

THE ROLE OF THIOL GROUPS IN THE DEVELOPMENT OF RADIATION DAMAGE IN THYMOCYTES AND EHRLICH ASCITES CARCINOMA CELLS

1964 ◽  
Vol 42 (12) ◽  
pp. 1717-1727 ◽  
Author(s):  
J. F. Scaife
Keyword(s):  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Irradiation Damage ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Ehrlich Ascites ◽  
X Irradiation ◽  
The Difference

The effect of 800–1000 rads of X-irradiation on the thiol content of thymocytes and Ehrlich ascites carcinoma cells has been compared. Four hours after irradiation there was a decrease in the non-protein thiol (NP.SH) content of thymus and thymocytes but no change in ascites cells. In both cells the main NP.SH compound was glutathione. There was no significant effect of irradiation on the protein thiol (P.SH) content of thymus or ascites cells, but there was a slight decrease in P.SH in thymocytes after 4 hours incubation. Isolated thymus nuclei showed an immediate small decrease in P.SH content following 800 rads in vitro. Nuclei isolated from rat thymus 1 hour after 1000 rads in vivo showed an increase in the SH content of the globulin fraction and a decrease in the SH content of the nucleohistones. The total SH content of thymocytes and ascites cells was reduced by slow diffusion of H2O2into the cell suspension, but no effect of prior irradiation on this decrease of SH was found. Inhibition of catalase in vivo and in vitro did not produce any of the morphological signs of irradiation damage in thymocytes. There was no effect of irradiation on the copper content of thymus, thymocytes, or ascites cells. The ratio of NP.SH/P.SH is higher in thymocytes than in ascites cells, but, allowing for the difference in cell size, the overall total thiol concentration was the same. Anoxia produced only a small increase in NP.SH content in both cells and a small and doubtful increase in P.SH. It is concluded that, if thiol groups are involved in cell sensitivity to radiation, only a small fraction of the total SH groups are involved at critical sites.

THE SYNTHESIS OF EXTRACELLULAR RIBONUCLEOSIDES BY ASCITES TUMOR CELLS IN VITRO

1965 ◽  
Vol 43 (2) ◽  
pp. 257-269 ◽  
Author(s):  
A. R. P. Paterson
Keyword(s):  
Tumor Cells ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Ascites Tumor ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells

Ehrlich ascites carcinoma cells in vitro converted extracellular hypoxanthine to extracellular inosine if uridine or guanosine was provided in the medium at the rate of 20–30 μmoles per milliliter of cells per hour. The synthesis of external uridine also took place when cells were incubated with uracil and a purine ribonucleoside, but at a lower rate than that of inosine. Intact Ehrlich ascites cells catalyzed an exchange between labelled uracil and uridine when both were present in the incubation medium.The synthesis of the extracellular ribonucleoside appeared to be mediated by ribonucleoside phosphorylases and to take place by the transfer of the ribosyl group from a donor ribonucleoside to an acceptor base.

The effects of coal tar and ultraviolet radiation upon the incorporation of thymidine into DNA by Ehrlich ascites carcinoma cells in vitro

1980 ◽  
Vol 58 (6) ◽  
pp. 743-749 ◽  
Author(s):  
I. A. Menon ◽  
H. F. Haberman
Keyword(s):  
Synergistic Effect ◽  
Dna Synthesis ◽  
Coal Tar ◽  
Mercury Vapor ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
In Vitro System ◽  
Summation Effect ◽  
Ehrlich Ascites

The effects of coal tar with and without radiation from three types of sources upon the incorporation of thymidine into DNA by Ehrlich ascites carcinoma cells were investigated. It was found that addition of varying concentrations of coal tar inhibited the thymidine incorporation by progressively greater amounts. Irradiation by mercury vapor lamp or fluorescent tubes, both emitting predominantly UVA (320–400 nm) and visible radiations, inhibited the DNA synthesis to a small extent. However irradiation with either of these sources in the presence of tar gave a synergistic effect on the DNA synthesis. Irradiation with a predominantly UVB (260–320 nm) source inhibited the DNA synthesis to a large extent. Irradiation with this source in the presence of coal tar did not give a synergistic effect but gave a summation effect. These findings have relevance in helping to choose the approporate radiation source for tar phototherapy of psoriasis. This in vitro system could also be used for other applications such as determining potencies of various tars or tar fractions.

STUDIES ON THE BIOSYNTHESIS OF NUCLEOTIDES IN EHRLICH ASCITES CARCINOMA CELLS IN VITRO

1965 ◽  
Vol 43 (2) ◽  
pp. 209-224 ◽  
Author(s):  
B. I. Uppin ◽  
P. G. Scholefield
Keyword(s):  
Exchange Reaction ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
The Other ◽  
Metabolic Inhibitors ◽  
Ehrlich Ascites ◽  
Oxidative Pathway ◽  
Time Courses ◽  
Oxidation Of Glucose

Studies have been made of the effects of metabolic inhibitors on the oxidation and incorporation of radioactivity into nucleotides of glucose labelled in the 1, 2, and 6 positions. The results indicate that in Ehrlich ascites carcinoma cells the predominant oxidative pathway is the hexosemonophosphate shunt. Investigation of the time courses of oxidation of the labelled glucose molecules confirms this conclusion. The pattern of incorporation of radioactivity initially suggests that nucleotide ribose is not formed via this pathway. However, it is shown that the coupling of an active transketolase system with the other enzymes of the hexosemonophosphate shunt provides a sufficient explanation of all the experimental observations. The conclusion is reached that pentose is formed by oxidation of glucose through the shunt but that the labelling pattern is largely established as the result of the exchange reaction catalyzed by transketolase.

scholarly journals K+/H+-antiporter nigericin arrests DNA synthesis in Ehrlich ascites carcinoma cells

1989 ◽  
Vol 86 (17) ◽  
pp. 6626-6629 ◽  
Author(s):  
L B Margolis ◽  
Y u Novikova I ◽  
I A Rozovskaya ◽  
V P Skulachev
Keyword(s):  
Membrane Potential ◽  
Dna Synthesis ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Low Concentrations ◽  
Ehrlich Ascites ◽  
Inhibition Of Dna Synthesis ◽  
Dna Synthesis Inhibition

Acidification of the cytoplasm of Ehrlich ascites carcinoma cells to pH 6.3 arrests DNA synthesis in these cells. Such an effect can be achieved by incubating the cells at pH 6.2 or by adding low concentrations of the K+/H+ antiporter, the antibiotic nigericin, at neutral pH. Glucose and anaerobiosis potentiate the nigericin effect. The inhibition of DNA synthesis by nigericin occurs without any significant decrease in the ATP concentration and in the mitochondrial membrane potential. The DNA synthesis inhibition is caused neither by a decrease in the intracellular [K+] nor by an increase in the intracellular [Na+] accompanying the nigericin effect (at least at low concentrations of the antibiotic). Nigericin should thus be regarded as a type of a cytostatic primarily affecting intracellular pH.

THE ENZYMIC FORMATION OF 6-(METHYLMERCAPTO)PURINE RIBONUCLEOSIDE 5′-PHOSPHATE

1966 ◽  
Vol 44 (2) ◽  
pp. 229-245 ◽  
Author(s):  
Ian C. Caldwell ◽  
J. Frank Henderson ◽  
A. R. P. Paterson
Keyword(s):  
Tumor Cells ◽  
Blood Cells ◽  
Intraperitoneal Injection ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Ehrlich Ascites ◽  
Mouse Tissues ◽  
Enzymatic Methods

6-(Methylmercapto)purine ribonucleoside (Me6MPR) is efficiently phosphorylated in mouse tissues and in Ehrlich ascites carcinoma cells in vivo; tumor cells in vitro and cell-free extracts of the tumor also phosphorylate this analogue ribonucleoside. The product of this reaction has been identified by chemical and enzymatic methods and by its chromatographic behaviour as Me6MPR 5′-phosphate. The evidence presented in this report indicates that no other major metabolites of Me6MPR are formed.The phosphorylation of Me6MPR by cell-free tumor extracts requires ATP and Mn2+ (or Mg2+), and evidence is presented that the reaction is probably mediated by adenosine kinase.Me-14C-6MPR is rapidly taken up by most mouse tissues following its intraperitoneal injection. Forty minutes after injection of the labeled drug, the highest levels of radioactivity were found in intestine, liver, blood cells, lung, and spleen, in descending order; virtually no radioactivity was found in brain tissue or in blood plasma.

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