الفهرس 
Title :Investigation of the distribution and expression of key genes in the fucose operon in escherichia coli
ContentsOnly 14 pages are availabe for public view
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Abstract
Many gut bacteria possess the ability to degrade multiple polysaccharides, thereby providing nutritional advantages to their hosts. Fucose, a hexose deoxy sugar, is one of the components of the carbohydrate mucins of the mucosal glycoconjugates. Recently, fucose was suggested to play a major role in communication between external microbial pathogens, e.g., Eshcerichia coli, Salmonella and the human resident microbiota; however, the exact role and involvement of every member of the fucose utilization operon has not yet been elucidated. Through comparative genomics and subsystems analysis of microbial genomes, the conservation and variation among fucose utilization genes, operons, and regulons was investigated in gut microbes such asE. coli, Shigella, Citrobacterand Salmonella. A major pattern of distribution of these fucose utilization genes in E. coli was found; yet, a variant pathway involving an ABC transporter system that replaces the fucose permease gene (fucP) was found in a small proportion of the genomes (50 out of 1058). Comparative genomics and subsystems analysis were confirmed byPCR screening, which showed that a minority of E. coli bacteria isolated from Egyptian individuals lacks the fucP gene while the majority had that gene well conserved. The conserved fucose isomerase-encoding gene, fucI, was detected in most, but not all, isolates. For further confirmation of fucose operon variants, fucP and fucI transcription was measured in different strains with different variants. In conclusion,E. coliwas found to utilize fucose by two pathway variants, reflected by a genetic change found within the operon in different strains