Document Detail

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity.
MedLine Citation:
PMID:  19706518     Owner:  NLM     Status:  MEDLINE    
The ulcer-causing gastric pathogen Helicobacter pylori is the only bacterium known to colonize the harsh acidic environment of the human stomach. H. pylori survives in acidic conditions by producing urease, which catalyzes hydrolysis of urea to yield ammonia thus elevating the pH of its environment. However, the manner in which H. pylori is able to swim through the viscoelastic mucus gel that coats the stomach wall remains poorly understood. Previous rheology studies on gastric mucin, the key viscoelastic component of gastric mucus, indicate that the rheology of this material is pH dependent, transitioning from a viscous solution at neutral pH to a gel in acidic conditions. Bulk rheology measurements on porcine gastric mucin (PGM) show that pH elevation by H. pylori induces a dramatic decrease in viscoelastic moduli. Microscopy studies of the motility of H. pylori in gastric mucin at acidic and neutral pH in the absence of urea show that the bacteria swim freely at high pH, and are strongly constrained at low pH. By using two-photon fluorescence microscopy to image the bacterial motility in an initially low pH mucin gel with urea present we show that the gain of translational motility by bacteria is directly correlated with a rise in pH indicated by 2',7'-Bis-(2-Carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF), a pH sensitive fluorescent dye. This study indicates that the helicoidal-shaped H. pylori does not bore its way through the mucus gel like a screw through a cork as has previously been suggested, but instead achieves motility by altering the rheological properties of its environment.
Jonathan P Celli; Bradley S Turner; Nezam H Afdhal; Sarah Keates; Ionita Ghiran; Ciaran P Kelly; Randy H Ewoldt; Gareth H McKinley; Peter So; Shyamsunder Erramilli; Rama Bansil
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-08-11
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  106     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-08-26     Completed Date:  2009-09-28     Revised Date:  2013-05-31    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  14321-6     Citation Subset:  IM    
Department of Physics, Boston University, Boston, MA 02215, USA.
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MeSH Terms
Bacterial Proteins / metabolism
Fluoresceins / chemistry
Gastric Mucins / chemistry,  metabolism*
Gastric Mucosa / metabolism,  microbiology*
Helicobacter pylori / enzymology,  physiology*
Hydrogen-Ion Concentration
Microscopy, Fluorescence
Mucus / metabolism,  microbiology*
Urea / chemistry,  metabolism
Urease / metabolism
Grant Support
Reg. No./Substance:
0/Bacterial Proteins; 0/Fluoresceins; 0/Gastric Mucins; 57-13-6/Urea; 85138-49-4/2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; EC

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