Talk: Sebastian Hess ‘Physiology and Evolution of Multiple Endosymbiosis in Spirostomid Ciliates’
Dr. Sebastian Hess, Independent Junior Research Group Leader (Emmy Noether Programme of the German Research Foundation), Institute of Zoology, University of Cologne, recently gave a talk during his virtual visit to the CRC 1182 at Kiel University:
“Physiology and evolution of ‘multiple endosymbiosis’ in spirostomid ciliates (Heterotrichea, Ciliophora)”
Endosymbiosis is a common phenomenon in protist cells, and led to major evolutionary innovations (e.g. evolution of the eukaryotic cell, phototrophic life). Many protists contain endosymbiotic algae and are able to indirectly utilize light as an energy source. Virtually all photosymbioses known today involve algae (e.g. green algae, dinoflagellates) or cyanobacteria, and, hence, are oxygenic (i.e. they produce oxygen). Currently, we study a widespread group of sediment-dwelling ciliates (the genera Spirostomum, Pseudoblepharisma), whose members display interesting endosymbioses with more than one type of intracellular inhabitants. This also includes the purple-green Pseudoblepharisma tenue, which contains anoxygenic (purple sulfur bacteria) and oxygenic (green algae) photobionts at the same time. With metagenomic and advanced microscopic approaches, we shed some light on how such extraordinary symbioses work and evolved. Our findings exemplify once more how symbiosis leads to unprecedented ‘composite organisms’ and the formation of new ecological niches.