title: Thymine auxotrophy is associated with increased UV sensitivity in Escherichia coli and Bacillus subtilis.
abstract: Thymine auxotrophy was shown to be associated with an increase in UV sensitivity both in Bacillus subtilis and in Escherichia coli. This UV sensitization became clearly evident in polA5 mutants of Bacillus subtilis: at UV doses of 16 J/m2, a reduction of more than 10-fold in the survivor population is observed in thymine requiring spontaneous mutants (polA5 thyA thyB) compared to the parental strains (polA5). Reversion of either thyA or thyB mutation led to a partial recovery in the UV resistance. This result suggests that DNA repair polymerization might be improved by the biosynthesis of thymidylate or some effect associated with such activity.
authors.affiliation: Cátedra de Genética Microbiana, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Argentina.
authors.forename: M M
authors.initials: MM
authors.lastname: Lojo
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000528:radiation effects; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D004256:DNA Polymerase I / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics; D004269:DNA, Bacterial / Q000528:radiation effects; D004926:Escherichia coli / Q000201:enzymology / Q000528:radiation effects; D009154:Mutation; D011836:Radiation Tolerance / Q000235:genetics*; D013489:Suppression, Genetic; D013940:Thymidylate Synthase / Q000096:biosynthesis* / Q000235:genetics; D013941:Thymine / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D013940:Thymidylate Synthase; D004256:DNA Polymerase I; D013941:Thymine