Transfer of a Gene for Sucrose Utilization into Escherichia coli K12, and Consequent Failure of Expression of Genes for D-Serine Utilization

Abstract

47As the first stage in investigating the genetic basis of natural variation in Escherichia coli, the gene(s) conferring the ability to use sucrose as a carbon and energy source (given the symbol sac+) was transferred from a wild strain to ~1 2 , which does not use sucrose. The sac+ region was transferred by two different methods. On both occasions it took a chromosomal location at minute 50-5 on the linkage map, between aroC and supN, in the region of the dsd genes, which confer the ability to use D-serine as a carbon and energy source. When the sac+ region was present in the K 12 chromosome the bacteria were unable to use D-serine as a carbon and energy source. In F'sac+/dsd+ diploids, the dsd+ genes were similarly not expressed. Strain ~1 2 ( s a c + ) bacteria were sensitive to inhibition by D-serine; they mutated to D-serine resistance with much greater frequency than did a dsd mutant of ~1 2 .Such bacteria also mutated frequently to use raffinose. Strain K l 2 ( S U C + ) bacteria did not utilize sucrose when they carried a mutation affecting the phosphotransferase system.

Adaptation of Sucrose Metabolism in the Escherichia coli Wild-Type Strain EC3132†

“…The gene dsdA, which codes for a D-serine-deaminase, is still present but is inactive due to the missing activator DsdC. This particular genotypic exclusion had been observed before (1,6), but its molecular basis was not clear.…”

Genetic evidence for a chromosomally integrated multiresistance plasmid in Salmonella dublin

“…Complete medium (Alaeddinoglu and Charles, 1979) was used for maintenance and culture of all bacterial strains. Minimal medium (Vogel and Bonner, 1956) supplemented with glucose or other sugars 0.2% w/v was used for all selections in genetic crosses.…”

Nutritional Variation in Escherichia coli

“…For ease of selection in genetic crosses, the characters of first choice were those concerned with the utilization of carbohydrates. So far, utilization of sucrose (Alaeddinoglu & Charles, 1979;Hill, 1980), L-sorbose (Woodward & Charles, 1982;Olukoya, 1984), and ribitol, D-arabitol and galactitol (Woodward & Charles, 1983) have been studied. Cloning of the genes encoding these characters was undertaken (Olukoya, 1984).…”