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 Hunting pathogens at full force
22.03.2017 | Helmholtz-Zentrum für Infektionsforschung

nachricht A 155 carat diamond with 92 mm diameter
22.03.2017 | Universität Augsburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>