title: Properties of thymineless strains of Bacillus megaterium.
abstract: Both Bacillus megaterium KM:T(-)R(1), a strain partially resistant to thymineless death, and strain KM:T(-), the parent strain, can satisfy their thymine requirement with either thymidine, 5-methyldeoxycytidine, or 5-methyluridine. Neither strain can use 5-methylcytosine, 5-hydroxymethylcytosine, 5-hydroxymethyluracil, or 5-aminouracil for this purpose. Strain KM:T(-)R(1) requires as little as 0.01 mM thymine for maximum growth, whereas strain KM:T(-) requires 0.10 to 0.20 mM thymine. Lysogenic KM:T(-)R(1) dies more rapidly in the presence of mitomycin C than the corresponding phage-sensitive strain. Unexpectedly, the lysogenic strain was found to be less sensitive to thymineless death than the phage-sensitive strain. Lysogenic KM:T(-)R(1) is induced by exposure to mitomycin C and by thymineless incubation. It is concluded that thymineless death occurs by a mechanism which is unrelated to phage induction and that a major lethal effect of mitomycin C is probably a consequence of phage induction.
mesh_terms: D001410:Bacillus megaterium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D001435:Bacteriophages / Q000254:growth & development; D002470:Cell Survival; D003470:Culture Media; D003562:Cytidine / Q000378:metabolism; D008242:Lysogeny; D008745:Methylation; D008937:Mitomycins / Q000494:pharmacology; D009154:Mutation; D013045:Species Specificity; D013936:Thymidine / Q000378:metabolism; D013941:Thymine / Q000378:metabolism*; D014529:Uridine / Q000378:metabolism
chemical_list: D003470:Culture Media; D008937:Mitomycins; D003562:Cytidine; D013941:Thymine; D013936:Thymidine; D014529:Uridine