fig1

Figure 1. Schematic outlining examples of the various mechanisms by which Bifidobacterium adhere to mucus. (A) Extracellular vesicles released by Bifidobacterium can bind to mucus, and in turn, this binding can inhibit pathogen colonization; (B) Bifidobacterium possess a wide array of pili and fimbriae, including FimM and its homologs, type 2 fimbriae, and type IVb pili, which bind to mucus; (C) Other proteins such as F1SBPs (family-1 binding proteins), BL0155 (a type of ABC transport transmembrane protein), GroEL (a heat shock protein), and EF-Tu (Elongation Factor Tu) are involved in mucus binding; (D) Endo-α-N-acetylgalactosaminidase, transaldolase, sialidase, and enolase are enzymes that facilitate mucus adhesion.