Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dependency can be an evolutionary advantage

07.11.2016

It is generally assumed that it is a good strategy for any kind of organism to be as independent from others as possible. A research team from the Max Planck Institute for Chemical Ecology in Jena, Germany, has now been able to show experimentally that quite the contrary may be the case: As a matter of fact, autonomous bacteria which lose their ability to produce certain amino acids autonomously gain an advantage by becoming dependent on others who provide these nutrients. This means that not only the acquisition of new traits, but also the loss of certain abilities drives the evolutionary adaptation of bacteria – and possibly also of other organisms – to their environment.

It has been known for quite some time that genetically modified bacteria, which have lost their ability to produce certain amino acids and retrieve these nutrients from their environment grow better than bacteria, which produce all nutrients themselves (see press release Division of Labor in the Test Tube, December 2, 2013).


Bacterial populations diversify into two genetically distinct populations: One retains biosynthetic capabilities and the other loses these functions. The latter thus becomes metabolically dependent.

Glen D’Souza, Christian Kost / Max Planck Institute for Chemical Ecology

This led Christian Kost, leader of the study and now professor at the University of Osnabrück, to inquire whether natural selection would favor the loss of abilities, thus making bacteria more dependent on their environment. To find out, Kost and his PhD student Glen D’Souza cultivated the gut bacterium Escherichia coli bacteria for several generations under optimal nutritious conditions. The culture was regularly transferred to a fresh nutrient solution, and during some of these transfers, a sample was taken to examine the bacterial capabilities and genes.

The results confirmed the assumption: A fraction of bacteria which had originally been autonomous lost their ability to produce metabolites, such as amino acids; they had become dependent on their environment which was enriched with these nutrients. “To our surprise, we found similar results when no nutrients had been added to the culture medium,” explained Glen D’Souza, the first author of the study. “The bacteria were divided into two groups: One group was still independent, whereas the other group had become dependent on these autonomous bacteria, which were still producing nutrients by themselves.”

A similar loss of traits has been observed not only in bacteria, but also in other groups of organisms. Many animals, including humans, are not able to produce vitamins themselves - they depend on their food or on vitamin-producing bacteria in their gut. Many pathogens need substances produced by their hosts in order to proliferate. Until now, it has been unclear why organisms would give up their autonomy and become dependent on others. This study now shows that the loss of capabilities may be evolutionarily advantageous and thus drive adaptation.

“There were further results we had not expected at all: When we studied the genome of the dependent bacteria, we found mutation not only in genes that are directly involved in the biosynthesis of amino acids, but also in genes, which regulate proteins that are involved in activating or inhibiting metabolic processes,” Christian Kost reports. This means that the adaptation of a bacterial population can be achieved in different ways. In the current study, this adaptation occurred only in one direction:

One group of bacteria became dependent on the other. However, the researchers are convinced that a longer testing period would have eventually resulted in mutual and more complex dependencies. Therefore, they plan to extend the duration of their experiment. Natural selection depends not only on the genetic endowment of a population, but also on its size. Depending on their lifestyle, natural bacterial populations differ considerably in size. Hence, the scientists want to find out how the size of bacterial populations affects the development of dependencies and the changes in the bacterial genomes.

A major problem in biological research is that most bacteria cannot be cultured under laboratory conditions. The results of the new study may explain why this is the case: Bacterial populations rapidly evolve metabolic dependencies on their environment by loosing the corresponding biosynthetic genes. Metagenomic analyses of environmental samples, which include the ecological interactions of microbial communities with their natural environments, may help solve this problem.

The experimental results are also relevant in more applied contexts: After all, bacterial communities play an important role in the health of plants, animals, and humans. Metabolic cooperation – that is, the question of how bacteria contribute to the exchange of metabolites – could become a decisive factor when bacterial communities are selected for application in agriculture or health care in order to support either growth or the defense against pathogens. [KG/AO]

Original Publication:
D’Souza, G., Kost, C. (2016). Experimental evolution of metabolic dependency in bacteria. PLOS Genetics. DOI: 10.1371/journal.pgen.1006364
http://dx.doi.org/10.1371/journal.pgen.1006364

Further Information:
Prof. Dr. Christian Kost, Abteilung Ökologie, Fachbereich Biologie, Universität Osnabrück, Barbarastraße 13, 49076 Osnabrück, Tel: Tel. +49 541 969-2853, E-Mail christiankost@gmail.com

Contact and Media Requests:
Angela Overmeyer M.A., Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-2110, E-Mail overmeyer@ice.mpg.de

Download high-resolution images via
http://www.ice.mpg.de/ext/downloads2016.html

Angela Overmeyer | Max-Planck-Institut für chemische Ökologie

More articles from Life Sciences:

nachricht More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>