Bromodeoxyuridine incorporation as a probe for studying the nature of radiation response of the slime mold, Physarum polycephalum. [Gamma radiation]
The effect of the incorporation of 5-bromodeoxyuridine into DNA on the induction of mitotic delay by radiation was studied in the synchronously dividing slime mold, Physarum polycephalum, in its vegetative stage, in an attempt to relate this radiation response to DNA damage. 5-Bromodeoxyuridine was incorporated into the DNA of Physarum polycephalum during (1) the first DNA synthesis period (S-I) following Mitosis I (first mitosis after fusion of microplasmodia) and the extent of unifilar substitution of deoxythymidine by 5-bromodeoxyuridine prior to Mitosis II was determined to be approximately 45%; or (2) the DNA synthetic periods following Mitosis I and Mitosis II (S-I and S-II) and the extent of bifilar substitution of deoxythymidine by 5-bromodeoxyuridine prior to Mitosis III was determined to be approximately 75%. There were significant increases in radiation induced mitotic delay observed in the molds (unifilar substitution) that had incorporated 5-bromodeoxyuridine from medium containing 100 ..mu..g/ml compared to nonsubstituted molds. There were significant increases in the radiation induced mitotic delay at Mitosis IV (with bifilar substitution) in plasmodia that had been grown in medium containing 25 ..mu..g/ml of 5-bromodeoxyuridine. When DNA from irradiated molds (harvested during S-II or G/sub 2/-II after 40,000 R) was subjected to alkaline sucrose density gradient centrifugation, it was found that the DNA from plasmodia treated with 5-bromodeoxyuridine initially contained more strand breaks than the similarly irradiated control molds. This difference was statistically significant in G/sub 2/ and suggests a correlation between the greater initial strand break damage observed in G/sub 2/ and the enhancement of radiation induced mitotic delay in the premitotic interval of G/sub 2/. No such correlation can be made for events in S with the results of the present study.
- OSTI ID:
- 7083168
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BUDR
RADIOSENSITIVITY EFFECTS
MITOTIC DELAY
RADIOINDUCTION
PHYSARUM
BIOLOGICAL RADIATION EFFECTS
CELL CYCLE
DNA
GAMMA RADIATION
MITOSIS
ANTIMETABOLITES
ANTIMITOTIC DRUGS
AZINES
BIOLOGICAL EFFECTS
BIOMASS
BROMOURACILS
CELL DIVISION
DRUGS
ELECTROMAGNETIC RADIATION
ENERGY SOURCES
FUNGI
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IONIZING RADIATIONS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANTS
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RENEWABLE ENERGY SOURCES
RIBOSIDES
URACILS
560131* - Radiation Effects on Microorganisms- Basic Studies- (-1987)