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: firstname.lastname@example.org
Katrin Bühler | Universität Basel
Making fuel out of thick air
08.12.2017 | DOE/Argonne National Laboratory
‘Spying’ on the hidden geometry of complex networks through machine intelligence
08.12.2017 | Technische Universität Dresden
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
11.12.2017 | Physics and Astronomy
11.12.2017 | Earth Sciences
11.12.2017 | Information Technology