22. June 2018

BASP study reveals hitherto unknown cause behind bacteria’s dormancy

Head of center Kenn Gerdes, together with post-docs Mohammad Roghanian and Kristoffer Skovbo Winther from the Center for Bacterial Stress and Persistence (BASP), has revealed the cause behind bacteria’s dormancy. This finding is important to understanding bacteria’s tolerance for antibiotics.

Bacteria are everywhere in nature, and they are known for their ability to survive under extreme conditions. The reason is that bacteria have developed a mechanism whereby they enter some sort of dormancy that makes them resistant to almost everything, including attacks from antibiotics.

At the DNRF center BASP, located at the Biological Institute at Copenhagen University, a group of researchers, composed of head of center Kenn Gerdes and post-docs Kristoffer Skovbo Winther and Mohammad Roghanian, have revealed how bacteria enter this state of dormancy.

The dormant state emerges when the human body is infected by disease-causing bacteria: here, the bacteria fight against immune cells in the body called macrophages. While macrophages attack the bacteria with toxic substances, the bacteria activate a defense mechanism called a stringent response. The mechanism changes the bacteria’s metabolism from fast to slow, so slow that it is like a state of dormancy, and this slow metabolism makes the bacteria resistant to the attacks of the macrophages.

Until now, the molecular mechanism that activates the bacteria’s stringent response has remained unknown, but in this new study, the research team from BASP has proved that bacteria can adjust their own growth, with important assistance from a molecule that warns the bacteria against potential danger.

“Most bacteria have an enzyme called Rel that forms a signal molecule called ‘alarmone’ in the cell, which tells the bacteria that there is danger ahead. It is this ‘alarmone’ that changes the bacteria’s metabolism to a stress-resistant condition: the bacteria decrease the growth rate and meanwhile start to demolish parts of the cell’s natural components and thereby liberate the fundamental components which the bacteria themselves need,” Gerdes explained to Copenhagen University.

Most bacteria are harmless, but there are a few that cause diseases: for instance, Salmonella typhi, which gives you typhus, Vibrio cholerae, which gives you cholera, and Pasteurella pestis, which gives you plague.

Read the scientific article at Cell here.

Further information on the research result and BASP can be found here (in Danish).

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