Meike Stumpp and Matthias Leippe
Evolution and function of digestive systems in marine metazoans: past, present, and future
Since the microbiome research expanded in the past years, the digestive system as prime host organ for microbes has recently gained a considerable attention not only by scientists but also by the public (also via public literature, e.g. “Gut: the inside story of our body’s most underrated organ” by Giulia Enders). This newly caught attention aside, the digestive system has historically already been described as the driving force for the evolution of multicellularity and the basis of metazoans: The Gastraea theory by Haeckel suggests that only after extracellular digestion in a digestive cavity (gastraea = primitive gut) had been evolved, it became energetically possible to grow larger organisms with specified tissues and the need for more specific communication strategies between host and microbes (immune system), and between cells and tissues within the organism (nervous system) emerged.
This PhD project will focus on the evolution of the digestive system in the past and future, by characterizing the digestive system physiology of organisms along the tree of life with emphasis on the transition from larval stages to their adult life stages (e.g. hydrozoans, molluscs, and echinoderms). Methodology involves classical physiological and molecular techniques such as determination of digestive enzyme activities, characterization of isolated digestive enzymes using protein analysis techniques, in situ hybridization, electrophysiological techniques such as gastric pH measurements, and microbiological methods (generation of germ-free larvae and infection assays). The project may also involve research stays at partner labs (Sweden or Taiwan) for collecting specimen samples and for conduction of experiments with life organisms in a climate change and/or pollution (microplastic) context.