Regulation of fucose and 1,2-propanediol utilization by Salmonella enterica serovar Typhimurium

Abstract

After ingestion, Salmonella enterica serovar Typhimurium (S. Typhimurium) encounters a densely populated, competitive environment in the gastrointestinal tract. To escape nutrient limitation caused by the intestinal microbiota, this pathogen has acquired specific metabolic traits to use compounds that are not metabolized by the commensal bacteria. For example, the utilization of 1,2-propanediol (1,2-PD), a product of the fermentation of L-fucose, which is present in foods of herbal origin and is also a terminal sugar of gut mucins. Under anaerobic conditions and in the presence of tetrathionate, 1,2-PD can serve as an energy source for S. Typhimurium. Comprehensive database analysis revealed that the 1,2-PD and fucose utilization operons are present in all S. enterica serovars sequenced thus far. The operon, consisting of 21 genes, is expressed as a single polycistronic mRNA. As demonstrated here, 1,2-PD was formed and further used when S. Typhimurium strain 14028 was grown with L-fucose, and the gene fucA encoding L-fuculose-1-phosphate aldolase was required for this growth. Using promoter fusions, we monitored the expression of the propanediol utilization operon that was induced at very low concentrations of 1,2-PD and was inhibited by the presence of D-glucose.

Respiration of Microbiota-Derived 1,2-propanediol Drives Salmonella Expansion during Colitis

“…To enhance initial growth, media were inoculated with a single strain or with an equal mixture of indicated S . Typhimurium strains resuspended in LB and incubated at 37°C for 24 hours, which was based on a similar protocol [38]. Bacterial numbers were determined by plating serial ten-fold dilutions onto LB agar containing the appropriate antibiotics.…”

Microbial Propionic Acid Production

“…Some organisms including Salmonella typhimurium [36] and Roseburia inulinivorans [21] are known to perform both processes, demonstrating a novel fermentative pathway for propionate production. PDO can be generated from the catabolism of deoxy sugars via lactate or from the glycolytic intermediate glycerone phosphate (DHAP) [37].…”

Metabolic functions of the human gut microbiota: the role of metalloenzymes

“…132,133 Interestingly, the B 12 -dependent dehydratases are primarily found in opportunistic enteric pathogens, including Salmonella and Klebsiella, perhaps enabling their expansion in the inamed gut. 134 Indeed, the expression of the B 12 -dependent enzyme in Salmonella enterica serovars Typhimurium confers a tness advantage and is considered a genetic determinant of pathogenicity. 135 Conversely, the GREs have been identied more oen in commensal organisms of the Clostridia class.…”