Modern eukaryotic cells contain numerous organelles, which once used to be independent bacteria. In order to understand how these bacteria were integrated into the cells in the course of evolution and how they are controlled, a research team from the Institute of Microbial Cell Biology at Heinrich Heine University Düsseldorf (HHU) has examined the single-celled flagellate Angomonas deanei, which contains a bacterium that was taken up relatively recently.