Arginine regulon control in a Salmonella typhimurium--Escherichia coli hybrid merodiploid.

The regulation of synthesis of arg enzymes was studied in a hybrid merodiploid in which an episome of Escherichia coli carrying the argR+ allele was transfered to Salmonella typhimurium argR strain. The arg enzyme levels of the hybrid merodiploid were compared to that found in argR and argR+ haploids of S. typhimurium. The results showed that repression of synthesis of arg enzymes was effected through the introduction of the E. coli argR+ allele but significant quantitative differences of arg enzyme levels in the argR+ haploid and the hybrid merodiploid were observed.