| dc.description |
PYRIMIDINES halogenated in position 5 have been shown to sensitize bacteria<sup>1</sup>, bacteriophages<sup>2</sup> and mammalian cells<sup>3</sup> to ultra-violet irradiation. In all these cases substitution of thymine, a specific constituent of deoxy-ribonucleic acid (DNA), by its halogenated analogues is implicated as the primary cause of increased sensitivity. This, together with the fact that one of the analogues, 5-bromouracil, is a known mutagenic agent in bacteria<sup>4</sup> and bacteriophages<sup>5</sup>, strongly suggests that genetic material, that is, DNA, is the primary target of irradiation. |
