Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.
For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell produces an antitoxin, thereby neutralizing a particular toxin, it grows normally. If the antitoxin is degraded, triggered for example by adverse environmental conditions, the toxin becomes effective and inhibits important cellular processes.
FIC toxins modify the spatial structure of the DNA (blue) of bacteria (red: cell membrane)
© University of Basel, Biozentrum
These systems act like a switch that interferes with bacterial growth and sends the bacteria into a state of dormancy in which they can be protected from the action of antibiotics. Prof. Christoph Dehio’s research group at the Biozentrum, University of Basel, has uncovered a new mechanism of action of toxins from the group of FIC proteins.
FIC toxin put bacteria into sleep mode
Toxin-antitoxin systems are ubiquitous in the bacterial world. The toxins usually inhibit protein synthesis or energy supply of the bacterium. Dehio’s team now first discovered such toxins among FIC proteins that can be found in all domains of life and demonstrated that they act by altering cellular DNA. The FIC toxins modify two target proteins, called topoisomerases, which give the bacterial DNA its characteristic twisted shape and monitor its spatial structure. The toxins completely shut down their activity.
“One can imagine as if FIC toxins pull the plug on topoisomerases”, explains Alexander Harms, first author and Fellowships for Excellence fellow at the Biozentrum. This rapidly leads to massive changes in the topology of cellular DNA, sending the bacteria into a kind of sleep state.
New insights into the evolution of pathogens
FIC proteins have a broad spectrum of molecular activities. Until now, research has mainly focused on FIC proteins which are injected as virulence factors by pathogenic bacteria into host cells. In their study, the scientists led by Dehio demonstrated for the first time a biological function of evolutionarily more ancestral FIC proteins, which still act within bacterial cells. This discovery could help to understand how pathogens and their tools arise in evolution.
Next, Dehio’s team aims to elucidate the evolutionary link between these original FIC toxins and the FIC proteins, which are injected as virulence factors into host cells by diverse pathogens.
Alexander Harms, Frédéric Valentin Stanger, Patrick Daniel Scheu, Imke Greet de Jong, Arnaud Goepfert, Timo Glatter, Kenn Gerdes, Tilman Schirmer & Christoph Dehio
Adenylylation of Gyrase and Topo IV by FicT Toxins Disrupts Bacterial DNA Topology
Cell Reports (2015), doi:
Prof. Dr. Christoph Dehio, University of Basel, Biozentrum, phone: +41 61 267 21 40, email: email@example.com
Katrin Bühler | Universität Basel
Insect Antibiotic Provides New Way to Eliminate Bacteria
15.11.2018 | Universität Zürich
New findings help to better calculate the oceans’ contribution to climate regulation
15.11.2018 | Jacobs University Bremen gGmbH
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
15.11.2018 | Life Sciences
15.11.2018 | Materials Sciences
14.11.2018 | Materials Sciences