Researchers in Oulu found a new defence mechanism in bacteria

The research group led by Anna Maria Pirttilä, docent of plant microbiology in the University of Oulu, has discovered a novel defence mechanism in bacteria. This knowledge can be used in the search for new antibiotics or for drugs against diseases caused by actions of harmful forms of oxygen, the so-called reactive oxygen species. Such diseases include retinal degeneration and Alzheimer’s disease.

The starting point of the study was to learn how the coexistence between pine and bacteria works. Plants and animals defend themselves against microbes, both good and bad. They produce large amounts of oxygen radicals into the infection site to prevent entry of microbes.

As a counter-measure, bacteria have developed a way to protect themselves. It was discovered that polyhydroxybutyrate, which is a long fatty acid chain acting as an energy storage for bacteria, surprisingly showed antioxidative activity when bacteria degraded it into short units.

Bacteria can produce large amounts of the fatty acid chain, even 90 per cent of the cell mass. This denotes the importance of the compound when antioxidants are rapidly needed in large amounts during e.g. an infection.

With the help of this knowledge we can look for new antibiotics, which disable bacteria’s ability to produce polyhydroxybutyrate that assists bacterial adaptation and survival.

The study, which was part of the thesis in the field of plant microbiology by doctoral student Janne Koskimäki, showed that such protection mechanism is widespread in bacteria, and that it is commonly connected with bacterial ability to endure hard conditions.

The study showed that the short fatty acid chains created in the degradation process of bacteria’s energy storage neutralized the most toxic form of oxygen, hydroxyl radical, as much as three times more efficiently than the well-known natural antioxidant of the cell, glutathione, and as much as ten times better than vitamin C. The compounds were discovered to protect also yeast cells from oxidizing environments.

The results of the study were published in March 2016 in the internationally acclaimed Nature Chemical Biology journal. The study was primarily funded by the Academy of Finland.

The results are currently being utilized in the University of Oulu in an ongoing project, which is funded by TUTLi of Tekes. The project is developing a treatment for macular degeneration.

Individual bacterial cells (Methylobacterium extorquens) are shown in grey. The red fluorescent granules inside the cells are polyhydroxybutyrate.


Maarit Jokela, Innovation Services


Last updated: 14.3.2016