Concert of Trumpets: Next Generation Taxonomy of Stentor

Single-celled organisms play a key role in every water body. Ciliates are particularly important for nutrient and carbon cycles. In our research project, we investigate certain ciliates, the so-called stentors, which traditionally serve as models for cell regeneration, physiology and pigments in biology. The trumpet-shaped, huge and colorful ciliates, measuring up to a few millimeters in size, are found worldwide, primarily in fresh water. Most species attach themselves to submerged substrates, some are considered plankton species. Most stentors feed on other organisms, some harbor bacteria and algae as symbionts. Their ecology is very specific, so they can serve as valuable indicators for assessing water quality. However, stentors are a significantly under-researched group of microorganisms and there are many problems with species assignment. To date, the characteristics for their identification are not completely reliable, which consequently leads to errors in defining their ecological profiles. The aim of our project is therefore an integrative characterization of the general appearance and ecology of Stentor, which also makes this genus a fully-fledged model for various areas of biology. In detail, we will examine the diversity of stentors worldwide, identify the ciliates themselves through microscopy and based on their gene sequences, detect other organisms that are hosted by the stentors and live in symbiosis together with them, and experimentally investigate the role of the color pigments that lead to predator - defense (e.g. from fish larvae). The collected data set will provide a very good basis for the use of stentors as bioindicator organisms and shed light on their role in different ecosystems. Our interdisciplinary and international research team is made up of specialists from various areas of biology and chemistry.