Thiolutin-resistant mutants of Salmonella typhimurium

Spontaneous mutants of Salmonella typhimurium isolated in our laboratory from thiolutin-containing tryptone agar plates are partially resistant to thiolutin in enriched media. In minimal media, they are not resistant. The mutants are not temperature sensitive but fail to support the development of phage P22 at higher temperatures (40 degrees C). Thiolutin did not interfere with RNA polymerase or nucleotide kinase in in vitro experiments. However, thiolutin did inhibit the rate of incorporation of exogenous uridine into the cellular pool and consequently the acid-precipitable material. It appears that one site of action of thiolutin is at the membrane level.