![]() ![]() coli O157:H7, helping to identify favorable intestinal environments for the development of severe disease. Overall, this study provides insights on the influence of the commensal microbiota on the pathogenicity of E. On the other hand, Stx2 production was enhanced when using NAG and inhibited with the rest of the metabolites, whilst Stx2 translocation was only enhanced when using NANA, and this increase occurred only through the transcellular route. We found that bacterial growth was maximum when using NAG and NANA compared to Galactose, Fucose or N-Gal, and that EHEC adhesion was inhibited regardless of the metabolite used. In the present work, we have studied the effects of five of the most abundant mucolytic activity-derived sugars, Fucose (L-Fucose), Galactose (D-Galactose), N-Gal (N-acetyl-galactosamine), NANA (N-Acetyl-Neuraminic Acid) and NAG (N-Acetyl-D-Glucosamine) on EHEC growth, adhesion to epithelial colonic cells (HCT-8), and Stx2 production and translocation across a polarized HCT-8 monolayer. ![]() EHEC can regulate the expression of some of its virulence factors through environmental sensing of mucus-derived sugars, but its implications regarding its main virulence factor, Shiga toxin type 2 (Stx2), among others, remain unknown. The normal commensal colonic microbiota has mucolytic activity and is capable of releasing the monosaccharides contained in mucins, which can then be used as carbon sources by pathogens such as Enterohemorrhagic Escherichia coli (EHEC). The human colonic mucus is mainly composed of mucins, which are highly glycosylated proteins. Since the production of one or more Stx is considered the major pathogenicity factor of STEC, we aim to highlight the new insights on the contribution of Stx phages and other STEC phages to pathogenicity. These prophages may carry foreign genes, some of them related to virulence, besides those necessary for the phage life cycle. In addition to Stx phages, the genome of pathogenic STEC bacteria may contain numerous prophages, which are either cryptic or functional. As members of the group of lambdoid phages, Stx phages share many genetic features with the archetypical temperate phage Lambda, but are heterogeneous in their DNA sequences due to frequent recombination events. After being assembled in the cytoplasm, and after host cell lysis, mature bacteriophage particles are released into the environment, together with Stx. Upon spontaneous induction or induction by chemical or physical stimuli, the stx genes are co-transcribed together with the late phase genes of the prophages. Shiga toxins (Stx) of Shiga toxin-producing Escherichia coli (STEC) are generally encoded in the genome of lambdoid bacteriophages, which spend the most time of their life cycle integrated as prophages in specific sites of the bacterial chromosome. This expansion of the nanS superfamily suggests important, though as yet unknown, functions in host-microbe interactions. Therefore, these original results extend our previous studies of nanS to include mucosal pathogens, prophage, and prophage remnants. The unexpected diversity of these enzymes suggests new avenues for investigating host-bacterial interactions. Our results further show that nanS homologs exist in bacteria other than Escherichia coli, as well as part of toxigenic E. Our results show that catabolism of the diacetylated form of host sialic acid requires a specialized esterase, NanS. Available evidence indicates diverse bacterial species use host sialic acids for adhesion or as sources of carbon and nitrogen. ![]() These sugars occur primarily as terminal carbohydrate residues on host glycoproteins and glycolipids. The sialic acids are a family of over 40 naturally occurring 9-carbon keto-sugars that function in a variety of host-bacterial interactions. ![]()
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