Communication between cells in plants, animals and humans takes place via specialised connecting structures. An international team led by biologists from Heinrich Heine University Düsseldorf (HHU) and involving the University of Tübingen has now discovered how the regulation of very similar structures was already present in multicellular bacteria, implying that this must have originated much earlier in the course of evolution. In the scientific journal published by the European Molecular Biology Organization (EMBO), they describe that the exchange of calcium plays a central role in bacteria, just as it does in humans.