Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Bacterial colonies evolve amazing diversity


Like human societies--think New York City--bacterial colonies have immense diversity among their inhabitants, often generated in the absence of specific selection pressures, according to a paper published ahead of print in the Journal of Bacteriology.

Microbiologists have long been aware of this phenomenon, and they credit it as a reason microbes have been able to colonize almost every conceivable terrestrial habitat from underground Antarctic lakes to hot springs to intensely radioactive pools, says corresponding author Ivan Matic, of INSERM, Paris. But none had tried to track it at the level of single cells.

"By using up to date experimental tools that allowed us to follow individual living cells, we were able to enter into this amazing, beautiful world of bacterial multicellular structures," says Matic.

"We observed massive phenotypic diversification in aging Escherichia coli colonies. Some variants showed improved capacity to produce biofilms, whereas others were able to use different nutrients, or to tolerate antibiotics, or oxidative stress, compared to the ancestral strain."

In the study, the researchers started each colony with a small number of identical cells, and observed them as they grew and as the colony aged. An aging colony is one where growth has stopped, because nutrients have been exhausted and/or toxins have accumulated.

"At this point most cells in the colony stop dividing and dead cells accumulate," says Matic.

Even in the growth phase, a colony is environmentally diverse. For example, since it grows on a solid medium, nutrients diffuse from the bottom up, resulting in a nutritional gradient with lower levels at greater elevation above the medium.

Similarly, oxygen and UV radiation decline with distance from the colony's surface, so that cells close to the top have ample oxygen, while those well below exist under anaerobic conditions.

In the elderly colony, the rising toxins and falling nutrients are also not homogeneously distributed. For example, despite general nutrient depletion, new nutrients become available from dead cells.

"We showed that the rare survivors of a senescent colony are very diverse and are different from their ancestors," says Matic. "We found different metabolic capacities, different levels of stress resistance, improved capacity to produce biofilms, and the ability to use different nutrients.

Some of these capacities probably evolved due to obvious selection pressures, such as utilization of alternative energy sources."


Journal of Bacteriology is a publication of the American Society for Microbiology (ASM). The ASM is the largest single life science society, composed of over 39,000 scientists and health professionals. Its mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

Jim Sliwa | Eurek Alert!
Further information:

Further reports about: ASM Escherichia capacity colonies diversification diversity levels nutrients toxins

More articles from Life Sciences:

nachricht Supercoiled DNA is far more dynamic than the 'Watson-Crick' double helix
13.10.2015 | University of Leeds

nachricht New Oregon approach for 'nanohoops' could energize future devices
13.10.2015 | University of Oregon

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Secure data transfer thanks to a single photon

Physicists of TU Berlin and mathematicians of MATHEON are so successful that even the prestigious journal “Nature Communications” reported on their project.

Security in data transfer is an important issue, and not only since the NSA scandal. Sometimes, however, the need for speed conflicts to a certain degree with...

Im Focus: A Light Touch May Help Animals and Robots Move on Sand and Snow

Having a light touch can make a hefty difference in how well animals and robots move across challenging granular surfaces such as snow, sand and leaf litter. Research reported October 9 in the journal Bioinspiration & Biomimetics shows how the design of appendages – whether legs or wheels – affects the ability of both robots and animals to cross weak and flowing surfaces.

Using an air fluidized bed trackway filled with poppy seeds or glass spheres, researchers at the Georgia Institute of Technology systematically varied the...

Im Focus: Reliable in-line inspections of high-strength automotive body parts within seconds

Nondestructive material testing (NDT) is a fast and effective way to analyze the quality of a product during the manufacturing process. Because defective materials can lead to malfunctioning finished products, NDT is an essential quality assurance measure, especially in the manufacture of safety-critical components such as automotive B-pillars. NDT examines the quality without damaging the component or modifying the surface of the material. At this year's Blechexpo trade fair in Stuttgart, Fraunhofer IZFP will have an exhibit that demonstrates the nondestructive testing of high-strength automotive body parts using 3MA. The measurement results are available in a matter of seconds.

To minimize vehicle weight and fuel consumption while providing the highest level of crash safety, automotive bodies are reinforced with elements made from...

Im Focus: Kick-off for a new era of precision astronomy

The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.

As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...

Im Focus: Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes

Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.

Inspired by insects

All Focus news of the innovation-report >>>



Event News

EHFG 2015: Securing healthcare and sustainably strengthening healthcare systems

01.10.2015 | Event News

Conference in Brussels: Tracking and Tracing the Smallest Marine Life Forms

30.09.2015 | Event News

World Alzheimer`s Day – Professor Willnow: Clearer Insights into the Development of the Disease

17.09.2015 | Event News

Latest News

Smart clothing, mini-eyes, and a virtual twin – Artificial Intelligence at ICT 2015

13.10.2015 | Trade Fair News

Listening to the Extragalactic Radio

13.10.2015 | Physics and Astronomy

Penn study stops vision loss in late-stage canine X-linked retinitis pigmentosa

13.10.2015 | Health and Medicine

More VideoLinks >>>