Featured research (3)

Organisms and their resident microbial communities − the microbiome − form a complex and mostly stable ecosystem. It is known that the specific composition and abundance of certain bacterial species have a major impact on host health and Darwinian fitness, but the processes that lead to these microbial patterns have not yet been identified. We here apply the niche concept and trait−based approaches as a first step in understanding the patterns underlying microbial community assembly and structure in the simple metaorganism Hydra . We find that the carrying capacities in single associations do not reflect microbiota densities as part of the community, indicating a discrepancy between the fundamental and realized niche. Whereas in most cases, the realized niche is smaller than the fundamental one, as predicted by theory, the opposite is observed for Hydra′s two main bacterial colonizers. Both, Curvibacter sp. and Duganella sp. benefit from association with the other members of the microbiome and reach higher fractions as in single colonisations. This cannot be linked to any particular trait that is relevant for interacting with the host or by the utilization of specific nutrients but is most likely determined by metabolic interactions between the individual microbiome members.
Inflammatory diseases, such as inflammatory bowel diseases, are dramatically increasing worldwide, but an understanding of the underlying factors is lacking. We here present an ecoevolutionary perspective on the emergence of inflammatory diseases. We propose that adaptation has led to fine-tuned host-microbe interactions, which are maintained by secreted host metabolites nourishing the associated microbes. A constant elevation of nutrients in the gut environment leads to an increased activity and changed functionality of the microbiota, thus severely disturbing host-microbe interactions and leading to dysbiosis and disease development. In the past, starvation and pathogen infections, causing diarrhea, were common incidences that reset the gut bacterial community to its "human-specific-baseline." However, these natural clearing mechanisms have been virtually eradicated in developed countries, allowing a constant uncontrolled growth of bacteria. This leads to an increase of bacterial products that stimulate the immune system and ultimately might initiate inflammatory reactions.
Phages are increasingly recognized as important members of host associated microbial communities. While recent studies have revealed vast genomic diversity in the virosphere, the new frontier is to understand how newly discovered phages may affect higher order processes, such as in the context of host-microbe interactions. Here, we aim to understand the tripartite interplay between phages, bacterial symbionts and marine sponges. In a viromics approach, we discover 491 novel viral clusters and show that sponges, as filter-feeding organisms, are distinct viral niches. By using a nested sampling design, we show that each sponge individual of the four species investigated harbours its own unique virome, regardless of the tissue investigated. We further discover a novel, symbiont phage-encoded ankyrin domain-containing protein which appears to be widely spread in phages of many host-associated contexts including human. The ankyrin protein (ANKp) modulates the eukaryotic immune response against bacteria as confirmed in macrophage infection assays. We predict that the role of ANKp in nature is to facilitate co-existence in the tripartite interplay between phages, symbionts and sponges and possibly in many other host-microbe associations.

Lab head

Thomas Bosch
  • Zoological Institute and Museum

Members (7)

Alexander V Klimovich
  • Christian-Albrechts-Universität zu Kiel
Peter Deines
  • Christian-Albrechts-Universität zu Kiel
Tim Lachnit
  • Christian-Albrechts-Universität zu Kiel
Katja Schröder
  • Christian-Albrechts-Universität zu Kiel
Jinru He
  • Christian-Albrechts-Universität zu Kiel
Kai Rathje
  • Christian-Albrechts-Universität zu Kiel
Bingli Chai
  • Fudan University
J. Wittlieb
J. Wittlieb
  • Not confirmed yet

Alumni (1)

Jay Bathia
  • Heinrich-Heine-Universität Düsseldorf