Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

For this microbe, cousins not particularly welcome

08.01.2010
A bacterial species that depends on cooperation to survive is discriminating when it comes to the company it keeps. Scientists from Indiana University Bloomington and Netherlands' Centre for Terrestrial Ecology have learned Myxococcus xanthus cells are able to recognize genetic differences in one another that are so subtle, even the scientists studying them must go to great lengths to tell them apart.

The scientists' report, which appears in a recent issue of Current Biology, also provides further evidence that cooperation in nature is not always a festival of peace and love. Rather, cooperation may be more of a grudging necessity, in which partners continually compete and undermine one another in a bid for evolutionary dominance.

"In some social microbes, cooperation is something that happens primarily among identical or very similar cells, as a way of competing against relatively unrelated individuals in other cooperative units," said IU Bloomington biologist Gregory Velicer, who led the research. "This is unlike humans, who are more likely to cooperate with unrelated individuals as well as with close kin. In the bacteria we study, cooperation appears to be highly restricted."

Myxococcus xanthus is a predatory bacterium that swarms through soil, killing and eating other microbes by secreting toxic and digestive compounds. When food runs out, cells aggregate and exchange chemical signals to form cooperative, multi-cellular "fruiting bodies." Some of the cells create the fruiting body's structure, while other cells are destined to become hardy spores for the purpose of surviving difficult conditions.

Previously, experiments by Velicer and Ph.D. student Francesca Fiegna showed that when different Myxococcus strains isolated from around the globe were mixed together, the number of spores produced was much reduced. This indicated that this social bacterium had diverged into many socially conflicting types. Michiel Vos, then a Ph.D. student with Velicer at the Max Planck Institute for Developmental Biology in Tübingen, Germany, set out to find whether Myxococcus bacteria sharing the same centimeter-scale soil patch were still capable of efficiently forming fruiting bodies together, or whether these close neighbors would already engage in social conflict.

As part of the experimental design for their Current Biology study, Velicer and Vos paired Myxococcus strains isolated from soil samples taken just centimeters apart to see whether they would behave cooperatively or competitively.

The scientists found that some pairs of strains, inhabiting the same patch of soil and almost identical genetically, had nevertheless diverged enough to inhibit each other's ability to make spores.

In general, however, the scientists found competition was less intense among centimeter-scale pairings than for pairings of more distantly related bacteria isolated from distant locations. These results indicate that social divergence can evolve rapidly within populations, but this divergence can be augmented by geographic isolation.

Another set of experiments revealed that different strains actively avoid each other prior to starvation-induced fruiting body formation. Velicer and Vos argue that this type of exclusion within diverse populations -- in which the probability of social conflict among neighbors is high -- may serve to direct the benefits of cooperation to close kin only.

Velicer says he plans to conduct an exhaustive search for specific genetic differences that lead to antagonism and social exclusion in pairing of closely related strains. "We've got lots of candidate genes," he said.

A long-term goal, Velicer explains, is to understand how new species of social bacteria might evolve sympatrically, that is, in a geographical area shared with a parental species.

"If strong social incompatibilities evolve rapidly, that has implications for understanding how interacting strains diverge over long periods of time," Velicer said.

The study was funded with grants from the National Institutes of Health, the Max Planck Society, the Deutsche Forschungsgemeinschaft, and the Netherlands Organisation for Scientific Research (Rubicon grant).

To speak with Velicer, please contact David Bricker, University Communicaitons, at 812-856-9035 or brickerd@indiana.edu. To speak with Vos, please e-mail michiel.vos@nioo.knaw.nl or call 011 31 26 479 12 05 (from the U.S. and Canada).

"Social Conflict in Centimeter- and Global-Scale Populations of the Bacterium Myxococcus xanthus," Current Biology, vol. 19, iss. 20

David Bricker | EurekAlert!
Further information:
http://www.indiana.edu

More articles from Life Sciences:

nachricht Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg

nachricht Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>