Identification and characterization of starvation-regulated genetic loci in Salmonella typhimurium by using Mu d-directed lacZ operon fusions.

We used the technique of Mu d-directed lac operon fusion formation in an effort to identify loci in Salmonella typhimurium which are transcriptionally regulated by nutrient starvation conditions. We identified lacZ operon fusions in eight genetic loci, all of which exhibited increased transcription when starved for two or more of the following nutrients: nicotinate, phosphate, ammonium, glucose, and sulfate. The loci have been designated stiA to stiH for starvation-inducible loci. Mutations in two sti loci (stiC and stiD) significantly decreased cell viability during prolonged periods of nicotinate starvation, stiA and stiD are linked and map at 30 min. The stiC, stiE, stiG, and stiH loci mapped at approximately 77, 43, 88, and 56 min, respectively, on the S. typhimurium linkage map.