Chemotaxis in run-reversing bacterial species*

Motile bacteria that localize all their flagella at one pole (polar-flagellates) engage in runs and reversals. This pattern of motility differs from the standard run and tumble model of E. coli. I will discuss how this subtle difference in cell movements makes it challenging to extend the canonical chemotaxis framework to explain biased migration in polar-flagellates. I will present our novel approach to characterize the chemotaxis signaling output in one such polar-flagellate, Helicobacter pylori. I will explain how the hydrodynamic coupling of motile H. pylori with underlying glass substrates makes it possible to quantify flagellar functions. Our results conclusively establish that H. pylori modulate flagellar functions similar to E. coli. I will discuss the implications of these findings for current understanding of chemotaxis in polar flagellates. Our discoveries hint at a novel regulatory module in the network. Broadly, these studies are biomedically significant as H. pylori cause certain types of stomach cancers and chemotaxis promotes their ability to target niches in the host.