Complex medium toxicity to some DNA repair-deficient strains of Salmonella typhimurium

The recovery of several strains of Salmonella typhimurium LT-2 which had first been grown in minimal medium varies when the organisms are grown on minimal medium agar and complex medium agar. The strains tested included mutants with deficiencies in DNA-repair systems (uvrB-and rec-), a deep rough (rfa-) mutant, and a double mutant carrying both the uvrB- and the rfa-mutation. The uvrB- and rec-mutations imparted sensitivity to complex medium agar. The rfa-mutation suppressed the sensitivity of the uvrB-mutant to complex medium agar. Differences in colony-forming ability were not observed when the bacteria were first grown in the complex medium broth.