Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Too much of a good thing: Extra genes make bacteria lethal

11.02.2015

We, as most animals, host many different beneficial bacteria. Being beneficial to the host often pays off for the bacteria, as success of the host determines the survival and spread of the microbe. But if bacteria grow too much they may become deadly.

In a new study published in the latest edition of the scientific journal PLOS Biology*, a research team from Instituto Gulbenkian de Ciencia (IGC; Portugal) found that a single genomic change can turn beneficial bacteria into pathogenic bacteria, by boosting bacterial density inside the host.


This image shows small yellow dots surrounding bright yellow cell nuclei in each cell are Wolbachia. The cytoskeleton (in red) allows seeing the shape of the cells.

Credit: Ewa Chrostek (IGC)

Ewa Chrostek and Luis Teixeira studied the symbiosis between a fruit fly (Drosophila melanogaster) and the bacterium Wolbachia to answer how benign bacteria become pathogenic. Wolbachia is present in most insect species and protects some of them against viruses, including the dengue fever virus.

Previous studies conducted by Luis Teixeira's team showed that the number of Wolbachia inside the fruit fly determines its effect on the host. Bacteria that reach very high levels inside the fly become harmful. Hence, this research team set out to investigate the genetic basis that control bacteria density inside the host and, consequently, their pathogenicity.

Comparison of pathogenic and non-pathogenic Wolbachia variants suggested that the number of repeats of a specific region of the genome, called Octomom, was causing the difference in Wolbachia virulence. The authors show that the number of copies of this region was variable between individual flies.

The bacteria with more Octomom copies grow faster reaching higher densities inside the fruit flies. Consequently, the more copies, the earlier the flies die. On the other hand, more copies of the Octomom region and higher Wolbachia levels in flies provide stronger antiviral protection.

Ewa Chrostek, who just finished her PhD at Luis Teixeira's laboratory, says: "We show that Octomom copy number can change rapidly, leading to different Wolbachia infection outcomes for the fly. These bacteria can evolve really fast and easily break away from hosts' control."

Luis Teixeira explains further: "We discovered a region of the Wolbachia genome responsible for regulation of its densities in the flies. This is the first study linking genes and their functions in this bacteria and it provides a unique point of entry for the understanding of the widespread insect-Wolbachia symbiosis."

Currently, as part of a strategy to control dengue transmission, mosquitoes (Aedes aegypti) infected with Wolbachia bacteria are being released in the wild. Therefore, understanding mechanisms of potential Wolbachia evolution and Wolbachia densities control is extremely important.

###

This research was carried out at Instituto Gulbenkian de Ciencia (Oeiras, Portugal). This study was funded by Fundacao para a Ciencia e a Tecnologia (Portugal) and the Wellcome Trust (UK).

* Ewa Chrostek and Luis Teixeira (2015). Mutualism breakdown by amplification of Wolbachia genes. PLOS Biology.

Ana Mena | EurekAlert!

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>