Date: 13.04.2026
How does a bacterium become part of another cell? Czech scientists describe a key step in evolution
An international team led by researchers from the Faculty of Science at the University of Ostrava and the Biology Centre of the Czech Academy of Sciences has described in detail how a bacterium became a permanent component of a host cell over the course of evolution. The findings shed light on one of the fundamental processes behind the emergence of complex cells in plants, animals and humans. They may also contribute to research on related parasites that cause diseases such as sleeping sickness.
The team, bringing together scientists from the Czech Republic, Germany and the United Kingdom, focused on the protozoan Angomonas deanei. This single-celled organism, related to parasites responsible for tropical diseases, is remarkable in that it permanently harbors a single bacterium inside its cell. While bacteria are often associated with disease, in this case the bacterium has become an indispensable partner that is entirely dependent on its host for survival.
Over the course of evolution, the bacterium has retained only a limited set of genes and can no longer function independently. This intimate relationship enabled the researchers to describe in detail the process by which a bacterium becomes integrated into a host
“We used a specialized method that allows us to determine the precise localization of proteins within the cell. Our analysis showed that the host cell actively targets its own proteins to the bacterium, thereby influencing its functioning and division. At the same time, there is an intensive exchange of metabolites essential for energy production and other cellular processes. In simple terms, the host cell has gradually adapted the bacterium to suit its own needs,” explains Professor Vjačeslav Jurčenko from the Faculty of Science at the University of Ostrava, who led the study.
The study, published in Nature Communications, suggests that the mechanism observed in this protozoan may resemble the ancient process that gave rise to mitochondria—the organelles responsible for energy production in modern cells. This transition represents one of the pivotal moments in the evolution of complex life on Earth. Without mitochondria, the cells of plants, animals and humans would not be able to function.
“Our research may also have practical implications. A better understanding of the metabolic processes and regulatory mechanisms in this protozoan could help identify new vulnerabilities in related parasites that cause diseases such as Chagas disease or leishmaniasis,” adds Professor Julius Lukeš from the Institute of Parasitology at the Biology Centre of the Czech Academy of Sciences.
The study, titled “Subcellular proteomics reveals a blueprint for endosymbiont integration in trypanosomatid Angomonas deanei,” has been selected for the Editors’ Highlights of Nature Communications, placing it among approximately fifty of the most significant recently published papers in microbiology. The paper has also attracted significant attention within the scientific community, including during a presentation by one of its authors, Michael Hammond, at the international EMBO | EMBL symposium in Heidelberg.
Publication
Hammond, M., Chmelová, Ľ., van Geelen-Kuenzel, N.A. et al. Subcellular proteomics reveals a blueprint for endosymbiont integration in trypanosomatid Angomonas deanei. Nature Communications 17, 2241 (2026). https://doi.org/10.1038/s41467-026-70084-0
