Spatially resolved symbiosis in anaerobic eukaryotes

Anaerobic protists are major predators of prokaryotes that affect the abundance, structure, and diversity of prokaryotic communities in important anaerobic environments such as sediments, rumina, and bioreactors. Some anaerobic protists engage in stable symbiosis with bacteria or archaea.

Very little direct experimental knowledge exists about their function, and there is scant evidence of how the protist cells domesticate and house their symbionts.

Anaeramoeba is a newly-described free-living protist with membrane-enclosed bacterial symbionts (Desulfobacter sp.) tightly associated with its hydrogen-producing mitochondria-related organelles (MROs).This four-year project will investigate the Anaeramoeba symbiont system in a spatially resolved manner.

First, we will study symbiosis-regulated expression changes when Anaeramoeba symbiosis is affected (symbiont switch, actin depolymerization, metabolic inhibition of symbiont sulfate-reduction) by metagenomics and metatranscriptomics.

Using spatial proteomics, the second aim is to establish a proteomic map of the Anaeramoeba-Desulfobacter symbiosis at subcellular resolution.

Proteins and organelles important in maintaining symbiosis will be identified by mapping symbiosis-regulated genes on the subcellular map.

We expect this project to delineate the details behind symbiosis between Anaeramoeba and Desulfobacter and, importantly, also give us a picture of how symbiotic interactions in anaerobic systems work in general.