Effectiveness of 1.5 keV aluminium K and 0.3 keV carbon K characteristic X-rays at inducing DNA double-strand breaks in yeast cells
Frankenberg, D.; Goodhead, D.T.; Frankenberg-Schwager, M.; Harbich, R.; Bance, D.A.; Wilkinson, R.E.
International Journal of Radiation Biology and Related Studies in Physics Chemistry and Medicine 50(4): 727-741
1986
ISSN/ISBN: 0020-7616 PMID: 3531058 Document Number: 281453
Induction of DNa double-strand breaks in diploid wild-type yeast cells, and inactivation of diploid mutant cells (rad54-3) unable to repair DNA doublestrand breaks, were studied with aluminium K (1.5 keV) and carbon K (0.278 keV) characteristic X-rays. The induction of DNA double-strand breaks was found to increase linearly with absorbed dose for both characteristic X-rays. Carbon K X-rays were more effective than aluminium K X-rays. Relative to 60Co .gamma.-rays the r.b.e.-values for the induction of DNA double-strand breaks were found to be 3.8 and 2.2 for carbon K and aluminium K X-rays respectively. The survival curves of the rad54-3 mutant cells were exponential for both ultrasoft X-rays. For inactivation of rad54-3 mutant cells, the r.b.e.-value relative to 60Co .gamma.-rays were 2.6 and 2.4 for carbon K and aluminium K X-rays, respectively. The DNA double-strand break data obtained with aluminium K and carbon K X-rays are in agreement with the data obtained for gene mutation, chromosome aberrations and inactivation of mammalian cells, suggesting that DNA double-strand breaks are the possible molecular lesions leading to these effects.