Ulcer-causing bacteria baffled by mucus: Viscoelasticity impact on collective behavior of swimming microorganisms

January 18, 2012
Researchers at Rensselaer Polytechnic Institute have discovered how certain polymers -- like those found in human mucus and saliva -- make it significantly more difficult for ulcer-causing bacteria to coordinate. The findings raise many new questions about the relationship between the individual and group behaviors of bacteria. The study also suggests that human mucus, saliva, and other biological fluid barriers may have evolved to disrupt the ability of harmful bacteria to coordinate. Credit: Rensselaer/Underhill

Even the tiniest microscopic organisms make waves when they swim. In fact, dealing with these waves is a fact of life for the ulcer-causing bacteria H. pylori.

The bacteria are known to change their behavior in order to compensate for the created by other bacteria swimming around in the same aquatic neighborhood. From the relatively simple actions of these individual bacteria emerges a complex, coordinated .

A new study by engineering researchers at Rensselaer Polytechnic Institute demonstrates how introducing certain polymers—like those found in human mucus and saliva—into the environment makes it significantly more difficult for H. pylori and other microorganisms to coordinate. The findings raise many new questions about the relationship between the individual and group behaviors of bacteria. The study also suggests that human mucus, saliva, and other biological fluid barriers may have evolved to disrupt the ability of harmful bacteria to coordinate.

"In the human body, microorganisms are always moving around in mucus, saliva, and other systems that exhibit elasticity due to the presence of polymers. Our study is among the first to look at how this elasticity impacts the collective behavior of microorganisms like H. pylori," said lead researcher Patrick T. Underhill, assistant professor in the Howard P. Isermann Department of Chemical and Biological Engineering at Rensselaer. "What we found is that polymers do in fact have a substantial impact on the flows created by the swimming bacteria, which in turn makes it more difficult for the individual bacteria to coordinate with each other. This opens the door to new ways of looking at our immune system."

Results of the study are detailed in the paper "Effect of viscoelasticity on the collective behavior of swimming microorganisms," recently published by the journal .

Underhill's study, based on large-scale computer simulations, leveraged the power of the Rensselaer Computational Center for Nanotechnology Innovations (CCNI), one of the world's most powerful university-based supercomputers. These simulations involved creating a computer model of more than 110,000 individual H. pylori bacteria simultaneously occupying a small volume of polymer-infused liquid. The simulations captured all of the individual actions and interactions created as the bacteria swam through the liquid. The most difficult aspect of this kind of simulation, Underhill said, is to identify collective behaviors and extract relevant conclusions from the massive amount of data generated.

See a video of a simulation:

The video will load shortly

In addition to computer simulations, Underhill employed theoretical models to understand how the addition of elasticity to liquid impacts the waves created by swimming H. pylori and, in turn, the of a large group of the bacteria. like H. pylori are known as pushers, as they propel themselves through water by twisting the long helical filaments that trail behind them.

Explore further: Going from ulcers to cancer

More information: See the paper online at: http://link.aps.org/doi/10.1103/PhysRevE.84.061901

Related Stories

Going from ulcers to cancer

August 22, 2008

Researchers have uncovered a big clue as to why some of the bacteria that cause stomach ulcers pose a greater risk for serious problems like stomach cancer than others; it turns out these bacteria can exploit the surrounding ...

Stomach ulcer bug causes bad breath

November 24, 2008

Bacteria that cause stomach ulcers and cancer could also be giving us bad breath, according to research published in the December issue of the Journal of Medical Microbiology. For the first time, scientists have found Helicobacter ...

Recommended for you

A tiny switch for a few particles of light

April 29, 2016

The Jedi knights of the Star Wars saga are engaged in an impossible fight. This does not result from the superiority of the enemy empire, but from physics because laser swords cannot be used for fighting like metallic blades: ...

Physicists detect the enigmatic spin momentum of light

April 25, 2016

Ever since Kepler's observation in the 17th century that sunlight is one of the reasons that the tails of comets to always face away from the sun, it has been understood that light exerts pressure in the direction it propagates. ...

Superfast light source made from artificial atom

April 26, 2016

All light sources work by absorbing energy – for example, from an electric current – and emit energy as light. But the energy can also be lost as heat and it is therefore important that the light sources emit the light ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

irjsiq
not rated yet Jan 18, 2012
From the relatively simple actions of these individual bacteria emerges a complex, coordinated group behavior.[q/]
Do these 'coordinated group behavior(s) not infer 'thought'?

Roy J Stewart,
Phoenix AZ

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.