How can bacteria understand where they are and coordinate their ability to cause disease? To understand this, Professor Jörgen Johansson is studying the bacterium Listeria monocytogenes.
Jörgen Johansson is a professor in molecular microbiology at the Department of Molecular Biology.
Jörgen uses the pathogenic bacterium Listeria monocytogenes as a model system to understand why bacteria can make people sick. The goal is to describe at the molecular level how the bacterium can understand where it is and how these systems make the bacterium pathogenic. He mainly looks at how so-called RNA molecules form and how this affects its activity, but also at how the bacterium reacts to stress. Together with other researchers at Umeå University, Jörgen is also trying to identify new types of antibiotics.
The Listeria bacterium is quite common in nature and we humans can ingest it through various foods, especially dairy products. In most cases, we do not get sick, but a large dose can lead to illness, especially in people with weakened immune systems, such as pregnant women. In adults, such a so-called listeriosis can manifest itself as meningitis or a general infection with bacterial spread in the blood. The mortality rate for listeriosis is very high, almost 30 percent. Therefore, it is also important to develop new treatment methods and preventive methods.
The Johansson lab has for more then 20 years studied the mechanism by how Listeria senses temperature to control its infectious potential. With the help of RNA molecules, the bacteria can control when they should produce toxic substances during an infection and also when they should block production, for example if they are outside the human body. This occurs through a thermostat-like function that causes an RNA molecule to have a closed structure at low temperatures. When the temperature becomes higher, for example in the human body, the structure opens and allows the production of toxins. The flexibility of RNA molecules creates very advanced signal chains in both bacteria and human cells.
Jörgen Johansson's research group has developed new advanced methods to determine what individual RNA molecules look like and whether they are "active" or "inactive". With these methods, they have identified several new RNA-based regulatory mechanisms that the bacteria use to cause disease.
Together with Umeå professors Sven Bergström, Fredrik Almqvist and Elisabeth Sauer-Eriksson, Jörgen Johansson's research group has also studied and investigated whether synthetic molecules can function as new types of antibiotics. The results are very promising, and they have also identified the mechanism for how these new antibiotics work in Listeria at the atomic level.