Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacteria develop restraint for survival in a rock-paper-scissors community

21.06.2011
It is a common perception that bigger, stronger, faster organisms have a distinct advantage for long-term survival when competing with other organisms in a given community.

But new research from the University of Washington shows that in some structured communities, organisms increase their chances of survival if they evolve some level of restraint that allows competitors to survive as well, a sort of "survival of the weakest."

The phenomenon was observed in a community of three "nontransitive" competitors, meaning their relationship to each other is circular as in the children's game rock-paper-scissors in which scissors always defeats paper, paper always defeats rock and rock always defeats scissors.

In this case, the researchers created nontransitive communities of three strains of Escherichia coli bacteria, one that produces two antibiotics, one that is resistant to both antibiotics and one that is sensitive to both. The sensitive strain outgrows the resistant strain, which outgrows the producer, which kills the sensitive strain.

In communities in which the resistant strain curbed its pursuit of the producer, the resistant strain thrived. With no restraint, the resistant strain greatly reduced the population of the producer. But then the resistant strain was forced into greater competition with the strain sensitive to the antibiotics and the resistant strain's short-term gain meant its long-term demise.

"By becoming a better competitor in a well-mixed system, it could actually drive itself to extinction," said Joshua Nahum, a University of Washington graduate student in biology. "By growing faster, it actually can hurt its abundance."

Nahum is the lead author of a paper describing the work published online the week of June 22 in the Proceedings of the National Academy of Sciences. Co-authors are Brittany Harding, a UW biology undergraduate, and Benjamin Kerr, a UW associate professor of biology and the paper's corresponding author.

The researchers created 192 pools in which the bacteria could grow and interact. The bacteria could migrate among pools, and when migration occurred among neighboring pools the three strains formed multi-pool patches.

"The restrained patches, the ones that grew slower, seemed to last longer and the unrestrained patches, the ones that grew faster, burned themselves out faster," Nahum said.

To understand the process, imagine a community of three strains, Rock, Paper and Scissors, and then imagine the emergence of an unrestrained supercompetitor, Rock* (rock star), that is able to displace Scissors even faster than regular Rock can. But that also makes Rock* a better competitor against Rock, the researchers said. Eventually Rock* will be a victim of its own success, being preyed upon by Paper.

The irony, Kerr said, is that "by chasing your victim faster you actually help out the guy who's chasing you." Restraining exploitive behavior is beneficial to the patch in the long run, he said, and is a realistic embodiment of the proverb "The enemy of my enemy is my friend."

"In patches with faster growth, members of the unrestrained patch burn through their victims and then are left to face their victims' victims, their own enemies," he said.

The observed effect only applies to structured communities with limited migration, the researchers said. In an unstructured community with greater migration and mixing, a species that curbed its aggressiveness would not reduce its chances of being engulfed by its enemy.

The findings have potential implications for other ecological systems, including mating systems of certain lizards that could have analogs among some reptiles, fish, birds and insects.

The work was funded by the National Institutes of Health and the National Science Foundation.

For more information, contact Kerr at 206-221-3996 or kerrb@uw.edu, or Nahum at nahumj@uw.edu.

Vince Stricherz | EurekAlert!
Further information:
http://www.uw.edu

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>