FIG 6.

Proposed model for the effect of DHMA on EHEC chemotaxis and virulence. (Left) (A) Mesenteric nerves from lymphoid follicles release norepinephrine (NE; •) into the gut lumen. (Right) Enlarged image of the boxed area in the left panel. (B) NE is sensed by QseC in commensal bacteria (green), resulting in expression of tynA and feaB, whose products convert NE to DHMA (▲). (C) A gradient of DHMA is formed from NE. (D) DHMA attracts pathogens, such as EHEC (red), through Tsr-mediated chemotaxis and induces pathogenesis through QseC.