Suppressor System in Bacillus subtilis 168

AUTOR(ES)
RESUMO

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 φe were isolated which can grow on the su+ and not on the su− strains.

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