Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Uncovering the secrets of ulcer-causing bacteria

17.08.2009
Clever biochemical strategy enables bacteria to move freely and colonize host

A team of researchers from Boston University, Harvard Medical School and Massachusetts Institute of Technology recently made a discovery that changes a long held paradigm about how bacteria move through soft gels.

They showed that the bacterium that causes human stomach ulcers uses a clever biochemical strategy to alter the physical properties of its environment, allowing it to move and survive and further colonize its host.

The Proceedings of the National Academy of Sciences reports the findings in its most recent issue. Helicobacter pylori is a bacterium that inhabits various areas of the stomach where it causes chronic, low-level inflammation and is linked to gastric ulcers and stomach cancer. In order to colonize the stomach, H. pylori must cope with highly acidic conditions in which other bacteria are unable to survive. It is well known however, that the bacterium accomplishes this by producing ammonia to neutralize the acid in its surroundings. In addition, newly published research shows it does something else; it changes its environment to enable freer movement.

Acidic conditions within the stomach also work against the bacteria's ability to move freely. This is due to a protein called "mucin," a crucial component of the protective mucus layer in the stomach. In the presence of acid mucin forms a protective gel, which acts as a physical barrier that stops harmful bacteria from reaching the cell wall.

But, H. pylori increases the pH of its surroundings and changes this "mucin" gel to a liquid, allowing the bacterium to swim across the mucus barrier, establish colonies, attack surface cells and form ulcers.

"Bacteria 'swim' through watery fluids using their tails to propel them," said Boston University physicist Rama Bansil, who is currently on leave from BU, working as a Division of Materials Research program manager at the National Science Foundation. "But it was not obvious how they move through a soft gel like mucus."

To answer the question Bansil, Shyam Erramilli and Jonathan Celli, also of Boston University, partnered with gastroenterologists Nezam Afdhal and Ciaran Kelly, and biochemists Sarah Keates, Bradley Turner and Ionita Ghiran at Harvard Medical School and mechanical and biomedical engineers Gareth McKinley, Peter So and Randy Ewoldt at MIT. The work began a few years ago as a feasibility study and was a part of Celli' Ph. D research.

Using video microscopes, the researchers found that when mucins extracted from mucus were in a liquid state, the bacteria could swim freely, but when mucins were in a gel state, the bacteria were stuck, even though their tails were rotating. More advanced imaging techniques revealed that pH changes directly correlated with the ability of the bacteria to move--the higher the pH, the greater the movement.

"This study indicates that the H. pylori, which is shaped very much like a screw, does not bore its way through the mucus gel like a screw through a cork as has previously been suggested," said Bansil. "Instead it achieves motility by using a clever biochemical strategy."

Researchers hope that the work will pave the way for future studies in native mucus and live animals to devise strategies for preventing H. pylori infection. Such studies could be important to the design of new therapeutic approaches that prevent the bacteria from colonizing in the first place, and also may be relevant to the broader question of bacterial infections in mucus linings in other organs.

View videos showing how the bacterium that causes stomach ulcers alters its physical environment allowing it to colonize and attack cells here:

http://www.acpt.nsf.gov/news/news_videos.jsp?cntn_id=115409&media_id=65494&org=NSF

http://www.acpt.nsf.gov/news/news_videos.jsp?cntn_id=115409&media_id=65493&org=NSF

Bobbie Mixon | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Life Sciences:

nachricht The dense vessel network regulates formation of thrombocytes in the bone marrow
25.07.2017 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg

nachricht Fungi that evolved to eat wood offer new biomass conversion tool
25.07.2017 | University of Massachusetts at Amherst

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>