Can an X-ray dose threshold be measured for the induction of SOS repair activity in E. coli.
Survival ("clonogenic ability") and induced DNA repair (SOS repair) have been studied at low X-ray doses in two Escherichia coli strains (GE94 and KY943), both of which contain a recA-lacZ protein fusion. X-ray doses greater than about 0.5 Gray clearly induce SOS repair activity. However, the threshold dose that just activates SOS repair is probably much lower than 0.5 Gray, perhaps as low as 0.001 Gray. It seems unlikely that this dose threshold can be more accurately measured with the recA-lacZ fusion technique.
Ewing
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Department of Radiation Oncology & Nuclear Medicine, Hahnemann University, Philadelphia, Pennsylvania 19102.
D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000235:genetics / Q000528:radiation effects*; D005798:Genes, Bacterial; D011938:Rec A Recombinases / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013014:SOS Response, Genetics / Q000528:radiation effects*; D013045:Species Specificity; D014965:X-Rays; D001616:beta-Galactosidase / Q000096:biosynthesis
D011993:Recombinant Fusion Proteins; D011938:Rec A Recombinases; D001616:beta-Galactosidase