Featured Research

from universities, journals, and other organizations

Secrets Of Ulcer-causing Bacteria: Clever Biochemical Strategy Enables Bacteria To Move Freely And Colonize Host

Date:
August 19, 2009
Source:
National Science Foundation
Summary:
A team of researchers 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.

Contact with stomach acid keeps the mucin lining the epithelial cell layer in a spongy gel-like state. This consistency is impermeable to the bacterium Heliobacter pylori. However, the bacterium releases urease which neutralizes the stomach acid. This causes the mucin to liquefy, and the bacterium can swim right through it.
Credit: Zina Deretsky, National Science Foundation

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.

Related Articles


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's 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.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. 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, and Rama Bansil. Helicobacter pylori moves through mucus by reducing mucin viscoelasticity. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0903438106

Cite This Page:

National Science Foundation. "Secrets Of Ulcer-causing Bacteria: Clever Biochemical Strategy Enables Bacteria To Move Freely And Colonize Host." ScienceDaily. ScienceDaily, 19 August 2009. <www.sciencedaily.com/releases/2009/08/090812163805.htm>.
National Science Foundation. (2009, August 19). Secrets Of Ulcer-causing Bacteria: Clever Biochemical Strategy Enables Bacteria To Move Freely And Colonize Host. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2009/08/090812163805.htm
National Science Foundation. "Secrets Of Ulcer-causing Bacteria: Clever Biochemical Strategy Enables Bacteria To Move Freely And Colonize Host." ScienceDaily. www.sciencedaily.com/releases/2009/08/090812163805.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) — Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) — Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com
Ebola: Life Without School in Guinea

Ebola: Life Without School in Guinea

AFP (Nov. 21, 2014) — Following the closure of schools and universities in Guinea because of the Ebola virus, students look for temporary work or gather in makeshift classrooms to catch up on their syllabus. Duration: 02:14 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins