1887

Abstract

The uptake of the labelled precursors, thymidine, deoxyadenosine and adenine, into the nuclear and mitochondrial DNA of the cellular slime mould, , at various stages of development was studied. Labelling of the different species of DNA, nuclear main-band, mitochondrial, and satellite, was analysed by CsC1 gradients using the AT-specific drug netropsin to enhance the density resolution. Constitutive and gamma ray modified uptake patterns were obtained. During early development, through late aggregation, constitutive uptake of thymidine and deoxyadenosine was exclusively into DNA at the density of mitochondrial and nuclear satellite I DNA, believed to be primarily due to mitochondrial DNA labelling. Labelled adenine was not incorporated into any DNA before early culmination. During the period of early culmination uptake of all three of these precursors into the main-band nuclear DNA increased dramatically, to considerably exceed uptake into the mitochondrial DNA. The molecular basis for these constitutive uptake patterns during development is not understood, but they appear to involve developmentally associated periods of DNA replication in some or all of the cells, possibly accompanied by changes in precursor transport and/or pool sizes that are different for the mitochondrial and nuclear DNA metabolic pathways. Early in development gamma rays had little effect on the constitutive uptake of precursor into the mitochondrial DNA but induced new dose-dependent uptake of thymidine and deoxyadenosine into the nuclear DNA. This unscheduled nuclear DNA synthesis may be a manifestation of gamma ray induced repair replication. At the early culmination stage gamma rays severely depressed the constitutive uptake of thymidine, deoxyadenosine and adenine into the nuclear DNA, to a level of about 10% at 20 krad. Higher doses induced a slight increase over this level. These changes may be due to the inhibition of the constitutive semiconservative replication by low gamma ray doses with the superposition of some induced repair replication.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-128-10-2439
1982-10-01
2021-08-04
Loading full text...

Full text loading...

/deliver/fulltext/micro/128/10/mic-128-10-2439.html?itemId=/content/journal/micro/10.1099/00221287-128-10-2439&mimeType=html&fmt=ahah

References

  1. Bonner J. T. 1967 The Cellular Slime Molds Princeton: Princeton University Press;
    [Google Scholar]
  2. Bonner J. T., Frascella E. B. 1952; Mitotic activity in relation to differentiation in the slime mold Dictyostelium discoideum. Journal of Experimental Zoology 121:561–571
    [Google Scholar]
  3. Clark J. M., Deering R. A. 1981; Excision of pyrimidine dimers from nuclear deoxyribonucleic acid in ultraviolet-irradiated Dictyostelium discoideum. Molecular and Cellular Biology 1:121–127
    [Google Scholar]
  4. Deering R. A., Jensen D. S. 1973; Nuclear and mitochondrial DNA synthesis in gamma ray-resistant and -sensitive slime mold amoebas. Biophysical Journal 13:780–794
    [Google Scholar]
  5. Deering R. A., Smith M. S., Thompson B. K., Adolf A. C. 1970; Gamma-ray-resistant and -sensitive strains of slime mold (Dictyostelium discoideum). Radiation Research 43:711–728
    [Google Scholar]
  6. Deering R. A., Adolf A. C., Silver S. M. 1972; Independence of propagation ability and developmental processes in irradiated cellular slime molds. International Journal of Radiation Biology 21:235–245
    [Google Scholar]
  7. Firtel R. A., Bonner J. 1972; Characterization of the genome of the cellular slime mold Dictyostelium discoideum. Journal of Molecular Biology 66:339–361
    [Google Scholar]
  8. Firtel R. A., Cockburn A., Frankel G., Hershfield V. 1976; Structural organization of the genome of Dictyostelium discoideum: analysis by EcoRI restriction endonuclease. Journal of Molecular Biology 102:831–852
    [Google Scholar]
  9. Ford W. T. Jr Deering R. A. 1979; Survival, spore formation and excision repair of UV-irradiated developing cells of D. discoideum. Photochemistry and Photobiology 30:653–659
    [Google Scholar]
  10. Guialis A., Deering R. A. 1976; Repair of deoxyribonucleic acid in ultraviolet light-sensitive and -resistant Dictyostelium discoideum strains. Journal of Bacteriology 127:59–66
    [Google Scholar]
  11. Hanawalt P. C., Friedberg E. C., Fox C. F. (editors) 1978 DNA Repair Mechanisms New York: Plenum Publishing Company;
    [Google Scholar]
  12. Katz E. R., Bourguignon L. Y. W. 1974; The cell cycle and its relationship to aggregation in the cellular slime mold, Dictyostelium discoideum. Developmental Biology 36:82–87
    [Google Scholar]
  13. Kielman J. K., Deering R. A. 1980; Ultraviolet light-induced inhibition of cell division and DNA synthesis in axenically grown repair mutants of Dictyostelium discoideum. Photochemistry and Photobiology 32:149–156
    [Google Scholar]
  14. Loomis W. F. Jr 1975 Dictyosteliumdiscoideum : A Developmental System New York: Academic Press;
    [Google Scholar]
  15. Ohnishi T., Okaichi K., Ohashi Y., Nozu K. 1981; Effect of caffeine on DNA repair of UV-irradiated Dictyostelium discoideum. Photochemistry and Photobiology 33:79–83
    [Google Scholar]
  16. Sussman R., Rayner E. P. 1971; Physical characterization of deoxyribonucleic acids in Dictyostelium discoideum. Archives of Biochemistry and Biophysics 144:127–137
    [Google Scholar]
  17. Takeuchi I., Yabuno K. 1970; Disaggregation of slime mold pseudoplasmodia using EDTA and various proteolytic enzymes. Experimental Cell Research 61:183–190
    [Google Scholar]
  18. Welker D. L., Deering R. A. 1978; Genetics of radiation sensitivity in the slime mouldDictyostelium discoideum. Journal of General Microbiology 109:1123
    [Google Scholar]
  19. Zada-Hames I. M., Ashworth J. M. 1978; The cell cycle and its relationship to development in Dictyostelium discoideum. Developmental Biology 63:307–320
    [Google Scholar]
  20. Zimmer C. 1975; Effects of the antibiotics netropsin and distamycin A on the structure and function of nucleic acids. Progress in Nucleic Acid Research and Molecular Biology 15:285–318
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-128-10-2439
Loading
/content/journal/micro/10.1099/00221287-128-10-2439
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error