The protein EpsE acts as a kind of coupling in bacteria and determines whether the bacteria are actively moving or not.
The mechanism for turning bacterial locomotion on and off works like a car's clutch: a protein connection at the interface determines whether or not the motor inside the cell is connected to the corkscrew-like drive shaft. This is what American scientists found out in the investigation of the so-called flagella? a complex of many proteins that serves as a complete drive unit for bacteria. The discovery was a coincidence, reports Daniel Kearns, the lead investigator. Actually, the researchers wanted to find out why bacteria that wander around lonely suddenly come together and form a structure called biofilm. These biofilms, in which the bacteria band together and surround with a protective layer of sugar, often play key roles in stubborn infections. The stability of the biofilm can be endangered by hyperactive bacteria, whose Flagellum called flagella continue to move steadily.

To understand how motion control and biofilm formation work together, scientists looked at the genes responsible for both. For the search for the link between the engine and the drive shaft they left? symbolized spoken? wagging the tail with the dog: they attached the end of the flagellum to a glass plate and observed whether the cells were moving in the presence or absence of various proteins. They came across a protein called EpsE. Once the EpsE gene in the bacteria was switched off, the cells would move once in five seconds. However, when the EpsE gene was switched on, the active movement ceased and the cells could only turn on passively. This protein is therefore responsible for the coupling or uncoupling of the drive shaft from the engine, the researchers conclude.

The findings could once help in the development of new drugs that directly affect the stability of biofilms? for example, by putting the EpsE gene on permanent duty, so that the bacteria can move constantly and thus can no longer form solid biofilms. The results also give nanotechnologists important clues on how to control tiny machines.

Daniel Kearns (University of Indiana in Bloomington) et al .: Science, Vol. 320, p. 1636 ddp / science.de? Uwe Thomanek advertisement

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