Archaea in Symbioses

Table 1

Some examples for symbioses between Archaea and other organisms (red Archaea, green Bacteria, blue-unicellular Eukarya, and metazoans).

Symbiotic partners	Examples	Interaction	Key features
	Ignicoccus hospitalis/Nanaoarchaeum equitans	Cell-cell contact	Transfer of essential biological macromolecules from host to symbiont
	SM1/Thiothrix	Cell appendages	Sulfur redox cycling?
	ANME-Archaea/sulfate reducing Bacteria	Cell-cell contact/ no direct contact	Anaerobic methane oxidation coupled to sulfate reduction
	Methanogenic; Archaea/Ciliates, Archamoebae	Endosymbiotic	Methanogen/hydrogenosome association, transfer of hydrogen, and/or C1/C2 compounds
	Porifera-associated Thaumarchaeota	Tissue associated	Ammonia oxidation
	Diverse associations between insect and vertebrate guts	Gut microbial communities	Methanogens as a terminal part of the anaerobic food chain