Campylobacter jejuni NCTC11168 and Bacteroides vulgatus ATCC 8482 Transcriptome

Fucosylated structures are abundant on epithelial cell surfaces, intestinal mucosa, plant digests and human milk oligosaccharides. Greater than half of sequenced Campylobacter jejuni isolates possess a pathway for L-fucose utilization. In C. jejuni NCTC11168, this operon is necessary for L-fucose chemotaxis and competitive colonization in a piglet diarrheal disease model, but the steps involved in L-fucose catabolism remain unknown. In this work, the structure of a putative dehydrogenase necessary for chemotaxis, Cj0485, was solved in complex with NADP and resembles the L-fucose dehydrogenase of Burkholderia multivorans. Cj0485 reduces both L-fucose and D-arabinose in vitro and both sugars are catabolized by the enzymes encoded by the fuc operon. NMR studies with 13C-L-fucose identified the intermediates leading to the production of pyruvate and lactate. This also allowed us to propose a pathway for D-arabinose catabolism. Although C. jejuni lacks glycosidases for sugar release, the organism exhibits enhanced growth when co-incubated with the gut microbe, Bacteroides vulgatus, both in vitro and in vivo. Yet when excess amino acids are available, C. jejuni shows a preference for their use providing evidence that a metabolic hierarchy exists that links through the TCA cycle. Overall, this work increases our understanding of nutrient metabolism by this common foodborne pathogen and highlights a possible commensal relationship with other gut microbes