The effect of trimethoprim on RNA synthesis in relaxed and stringent Escherichia coli strains.

Abstract

Trimethoprim inhibits growth, protein synthesis, and RNA synthesis in both stringent and relaxed cells grown in unsupplemented minimal medium. A preferential inhibition of RNA synthesis in rel+ cells is encountered when these cells are grown in media supplemented with purines. Trimethoprim decreases the quantity of purine nucleoside triphosphates in the acid‐soluble pool of both relaxed and stringent cells grown in minimal medium. When trimethoprim is added to cells grown in the presence of guanine, it decreases the purine nucleoside triphosphate pool in the stringent cell only.