Microbiologists and molecular biologists at ETH Zurich and the University of Bonn have discovered a new agent in fungi that kills bacteria. The substance, known as copsin, has the same effect as traditional antibiotics, but belongs to a different class of biochemical substances. Copsin is a protein, whereas traditional antibiotics are often non-protein organic compounds.
The researchers led by Markus Aebi, professor of mycology, discovered the substance in the common inky cap mushroom Coprinopsis cinerea that grows on horse dung. When they began their research, the scientists were interested in understanding how this fungus and various bacteria affect each other’s growth. This involved cultivating the fungus in a laboratory along with several different types of bacteria. It was found that C. cinerea is able to kill certain bacteria. Further research demonstrated that the copsin produced by the mushroom is responsible for this antibiotic effect.
Copsin belongs to the group of defensins, a class of small proteins produced by many organisms to combat microorganisms that cause disease. The human body also produces defensins to protect itself against infections. They have been found, for example, on the skin and in the mucous membranes.
For Aebi, the main focus of this research project was not primarily on applications for the new substance. “Whether copsin will one day be used as an antibiotic in medicine remains to be seen. This is by no means certain, but it cannot be ruled out either,” he says.