Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacteria mutate much more than thought

14.08.2007
In a study just published in the journal Science, Portuguese scientists show that in bacteria the rate of beneficial mutations – those that increase the capacity of an organism to survive in a particular environment – is much higher than previously thought.

In the case of Escherichia coli, the bacteria studied, this is as much as 1,000 times higher than previously believed. The study also suggests that many more genes mutate during bacteria adaptation to a new environment than previously thought. Both results - a much higher rate of advantageous mutations and a bigger number of genes mutating - have important implications for studies in antibiotic resistance and also how bacteria develop the capacity to attack their host.

Natural selection – the basis of evolution - is the process by which some organisms are more capable of life and self-reproduction because they are better fitted to a particular environment. And mutations are the raw material of evolution, in the sense that they are the source of new characteristics which equip the adapted organism with a bigger or smaller chance of survival.

But mutations can be either beneficial or disadvantageous, and although beneficial mutations are the crucial force behind adaptation and survival to a new environment, disadvantageous mutations are much better studied.

There are several reasons for this, the first relies on the fact that while “bad” mutations are very easily seen – the organism tends to die and disappear – “good” mutations tend to have a very small effect in the overall adaptation of individuals and so are easily missed. The fact that beneficial mutations with big effects are rare is because when an organism is already living in a particular environment means that is already adapted to it, and so does not need (or can even go through) radical changes.

The second reason is because in big populations where organism reproduce very quickly and many beneficial mutations occur at the same time – and these are the only populations where the studies can be done, since only in them evolution occurs on a visible timescale - there is competition between organisms with different mutations. This means that in the end, those with the most beneficial mutations will be reproducing in higher numbers masking the other mutations – this process is called “clonal interference” - and leads to an underestimation of the mutation rate.

The difference in the study of Lidia Perfeito, Isabel Gordo and colleagues from the Institute Gulbenkian of Science in Lisbon, Portugal, is that they measured the mutation rate of Escherichia coli in many different sized populations, including some small enough to avoid clonal interference although big enough to avoid disadvantageous mutations to spread too easily and kill the population. Through the comparison of these different size populations, which ranged from to 20,000 cells to 10 million, Perfeito, Gordo and colleagues reached an amazing conclusion: that Escherichia coli mutation rate was a thousand times bigger than previously predicted and that thousand of mutations were going overseen because “better” ones overtook them in the population.

Although these studies were done in Escherichia coli - a very common bacterium found in the intestine of vertebrates, including man – the research by the group of Portuguese scientists potentially applies to any bacteria and will be especially important in the study of disease-inducing bacteria.

The importance of Perfeito, Gordo and colleagues’ results resides in two facts: first the fact that they show that beneficial mutations in bacteria are much more common than previously predicted suggesting that bacteria can adapt both to anti-bacterial medication, but also to their host, much quicker than previously thought and second the fact many more bacterial genes are mutating than those seen in the population what can have implications for the way evolution is understood.

As the team leader explained to the Portuguese Agency of News Lusa, "This study is a substantial contribution to the understanding of a central problem in the theory of evolution and has important implications for public health, more specifically for the understanding of antibiotic resistance and the development of new medicines against bacteria."

Piece researched and written by catarina.amorim at linacre.ox.ac.uk

Catarina Amorim | alfa
Further information:
http://www.sciencemag.org/cgi/content/full/317/5839/813

Further reports about: Coli Escherichia Escherichia coli beneficial

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>