Helicobacter pylori (H. pylori), a bacterium linked to an increased risk of gastric cancer and other illnesses such as peptic ulcers and gastritis, colonize a majority of the world population’s stomachs. Currently, H. pylori infections are treatable with a cocktail of antibiotics, but the rapid emergence of antibiotic resistance in H. pylori is a significant concern. To counter these threats, Dr. Pushkar Lele investigated how H. pylori locate their ideal environment within a host’s stomach.
Motile bacteria, such as H. pylori, swim by rotating string- like appendages called flagella. They navigate by sensing chemical signals in their environment, a process known as chemotaxis. An intracellular signaling pathway — the chemotaxis network — aids navigation by controlling the direction of rotation of the flagella. Current understanding of how the chemotaxis network operates is based on studies of E. coli, which is a model system for bacterial chemotaxis and motility. The chemotaxis network in E. coli modulates the probability of clockwise rotation in otherwise counterclockwise-rotating flagella to help the cell migrate toward favorable chemical environments. How the chemotaxis network modulates flagellar functions in H. pylori is not known.
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Lele said the similarity in the form of flagellar control in the two bacterial species is intriguing given that they differ in several key aspects. Whereas H. pylori prefer the stomach, E. coli are found in the lower gastrointestinal tract. The physical characteristics of H. pylori are such that they run forward and reverse, unlike E. coli, which run forward and then tumble. As a result, the modulation of the probabilities of clockwise flagellar rotation, which suits E. coli very well, is predicted to cause errors in chemotaxis in H. pylori. With a greater understanding of the H. pylori chemotaxis network, it may be possible to disrupt the network, and in turn the bacterial infections, without the use of antibiotics.
FEATURED RESEARCHER
Dr. Pushkar Lele
- Associate Professor