title: Suppressor system in Bacillus subtilis 168.
abstract: Multiple auxotrophic strains of Bacillus subtilis 168 were tested for joint one-step reversion of two or more auxotrophic markers to the wild-type phenotype. Mu8u5u5, a strain requiring leucine, methionine, and threonine, yielded revertants that grew without added methionine or threonine and proved to have a suppressor gene. When transferred by transformation with deoxyribonucleic acid, this suppressor gene also suppressed the adenine mutation in another strain, Mu8u5u6. The one-step double revertants fell into two distinct classes: strains of class su(+) (I) grow well in broth; strains of class su(+) (II) grow poorly. Strains su(+) (II) tend to revert frequently to the su(+) (I) or su(-) state. Conditional lethal mutants of phage phie were isolated which can grow on the su(+) and not on the su(-) strains.
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects / Q000302:isolation & purification; D001435:Bacteriophages; D005796:Genes; D005827:Genetics, Microbial; D008722:Methods; D009153:Mutagens / Q000494:pharmacology; D009154:Mutation; D013489:Suppression, Genetic; D014170:Transformation, Genetic
chemical_list: D009153:Mutagens