Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How E. coli evolves to adapt to changing acidity

30.05.2007
One in a series of studies on laboratory studies of selection and evolution

Forthcoming in Physiological and Biochemical Zoology, a fascinating new selection of papers collects leading experimental research in evolution and artificial selection, providing insight into how organisms adapt to changing environmental conditions and fluctuations.

Dr. James Hicks, Editor in Chief of PBZ, explains the momentum behind this collection of papers: "This exciting approach – experimental evolution – allows scientists to investigate the fundamental mechanisms of evolution. Prior to the advent of contemporary laboratory techniques, inferences about evolution were based on observation. Now, we can study evolutionary change as it is happening, by selecting organisms that change rapidly, such as the fruit fly or E. coli. This advantage allows scientists to investigate how changes occur and how they affect an organism's individual physiology and overall community."

In the July/August 2007 issue, the first of three issues that will contain articles from the collection, Bradley S. Hughes, Alistair J. Cullum, and Albert F. Bennett (University of California, Irvine) explore the effect on E. coli of fluctuating acidity, an especially important environmental factor for the bacteria.

... more about:
»Coli »E. coli »adapt »experimental

E. coli may spend hundreds or thousands of generations in the relatively neutral-acidity colon, with brief exposure to the extreme acidity of the stomach and modest alkalinity in the small intestine during colonization of a new host. With modern sewage handling (or mishandling), the bacteria may also experience exposure to the ocean, with a pH near 8.0, before infecting a new host.

To assess how E. coli might adapt to different environmental conditions, the researchers observed four groups of bacteria. One group was exposed to constant acidity (pH of 5.3) and another to constant alkalinity (pH of 7.8). A third group was exposed to randomly fluctuating pH levels, and the fourth was exposed to pH levels that cycled daily between acidic and basic conditions.

After at least 1,000 generations, the researchers exposed the groups to either an acidic or basic environment. The groups exposed to acid or base for the entire period had developed into specialists – that is, they displayed significant fitness gains when transitioning into their preferred environment.

In contrast, the groups that evolved in variable pH environments exhibited generalist fitness patterns, with neither group having any significant fitness loss in any of the environments. Interestingly, the researchers also found that there was no significant cost to being a generalist at any tested pH level: "Overall, these comparisons suggest that the jack-of-all-trades may be a master of at least some as well," the researchers write.

"What is interesting here is that the complex patterns of adaptation in the various pH regimes were so different among the groups and revealed the first empirical characterization of the intricacies of evolution in response to variable pH," explain the authors. "Plans for future studies include the extension of this experimental evolution system applied to . . . ways in which E. coli may be evolving fitness to survive within the coastal ecosystem or the human host."

Papers from the focused collection, "Experimental Evolution and Artificial Selection" will also appear in the September/October and November/December 2007 issues.

Focused Issue: Experimental Evolution and Artificial Selection (July/August 2007)

"Do Species Converge during Adaptation" A Case Study in Drosophila"
Carla Rego, Michael R. Rose, and Margarida Matos
"Laboratory Evolution of the Migratory Polymorphism in the Sand Cricket: Combining Physiology with Quantitative Genetics"

Derek A. Roff and Daphne J. Fairbairn

"Evolutionary Adaptation to Freeze-Thaw-Growth Cycles in Escherichia coli"
Sean C. Sleight and Richard E. Lenski
"Using Experimental Evolution to Study the Physiological Mechanisms of Desiccation Resistance in Drosophila melanogaster"

Margaret A. Archer, Timothy J. Bradley, Laurence D. Mueller, and Michael R. Rose

"Experimental Evolution of Olfactory Memory in Drosophila melanogaster"
Frederic Mery, Juliette Pont, Thomas Preat, and Tadeusz J. Kawecki
"An Experimental Evolutionary Study on Adaptation to Temporally Fluctuating pH in Escherichia coli"

Bradley S. Hughes, Alistair J. Cullum, and Albert F. Bennett

Suzanne Wu | EurekAlert!
Further information:
http://www.uchicago.edu

Further reports about: Coli E. coli adapt experimental

More articles from Life Sciences:

nachricht Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg

nachricht Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Rapid environmental change makes species more vulnerable to extinction

19.10.2017 | Life Sciences

Integrated lab-on-a-chip uses smartphone to quickly detect multiple pathogens

19.10.2017 | Interdisciplinary Research

Fossil coral reefs show sea level rose in bursts during last warming

19.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>