INSENSITIVITY TO IONIZING RADIATION OF DNA-POLYMERASE IN A SLIME MOLD
In the plasmodial slime mold Physarum polycephalum the nuclear divisions are synchronous. Synthesis of DNA occurs very shontly after the division and occupies a relatively brief period of the cell cycle. In contrast to the intermittent occurrence of DNA synthesis the formation of thymidlne triphosphate from non-phosphorylated precursors (orotic acid and thymidine) takes place throughout interphase. DNA-polymerase, the enzyme capable of polymerizing deoxynucleoside triphosphates in the presence of primer or template-DNA, has been demonstrated in extracts of molds harvested at any time of the cell cycle. Extracts made from molds irradiated during interphase with 100,000 r of x radiation showed no decrease in polymerase activity as compared with extracts from unirradiated controls. It appears that in Physarum the DNA synthesis is not controlled by variations in the amount of DNA-polymerase and, furthermore that this enzyme is very insensitive to ionizing radiation. (auth)
- Research Organization:
- Western Reserve Univ., Cleveland
- DOE Contract Number:
- W-31-109-ENG-78
- NSA Number:
- NSA-17-001241
- OSTI ID:
- 4773960
- Report Number(s):
- TID-17013
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
Similar Records
Theoretical approach to the effects of extremely low freqency electromagnetic fiels on Physarum polycephalum. [Slime molds]
Spatiotemporal Symmetry in Rings of Coupled Biological Oscillators of Physarum Plasmodial Slime Mold