Effect of ionizing radiation on nucleoside metabolism in Physarum polycephalum. [. gamma. rays; reduced DNA synthesis results in increased deoxynucleoside triphosphate concentration in plasmodia]
The pool sizes and specific activities of deoxynucleoside triphosphates (dNTPs) were determined in control and irradiated S-phase plasmodia of Physarum polycephalum following incubation in the presence of labeled deoxynucleosides. Irradiation (10-kR /sup 60/Co ..gamma.. radiation) was found to increase the intraplasmodial concentrations of all four dNTPs to a similar extent (127 to 158% of the control value). The increase in dNTP concentrations generally paralleled a radiation-induced decrease in the rate of DNA synthesis. The results suggest that the increase in dNTP levels is caused by a reduction in the rate of their utilization for DNA synthesis. The effect of irradiation on the specific activity of the dNTPs depended upon the labeled precursor utilized. Thus, when thymidine, deoxyadenosine, or deoxyuridine was used, the specific activities of TTP, dATP, or TTP, and dCTP, respectively, were reduced to about 50% of the control values. However, when deoxycytidine was used as the labeled precursor, the specific activities of dCTP and TTP were either unchanged or actually increased in the irradiated samples. It is concluded that the phosphorylation of deoxycytidine is increased in irradiated plasmodia.
- Research Organization:
- Case Western Reserve Univ., Cleveland, OH
- OSTI ID:
- 6433120
- Journal Information:
- Radiat. Res.; (United States), Vol. 76:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
BIOLOGICAL RADIATION EFFECTS
BIOSYNTHESIS
NUCLEOSIDES
METABOLISM
PHYSARUM
COBALT 60
GAMMA RADIATION
LETHAL IRRADIATION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOMASS
COBALT ISOTOPES
ELECTROMAGNETIC RADIATION
ENERGY SOURCES
FUNGI
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
IRRADIATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUCLEIC ACIDS
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PLANTS
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RENEWABLE ENERGY SOURCES
RIBOSIDES
SYNTHESIS
YEARS LIVING RADIOISOTOPES
560131* - Radiation Effects on Microorganisms- Basic Studies- (-1987)