Genomic study of M. maripaludis and D. vulgaris cultures
Syntrophic interactions between bacteria and archaea are vital for anaerobic processes, relying on close cell-to-cell contact for efficient metabolite and electron transfer. Membrane-associated proteins and lipids likely play key roles in stabilizing these contacts, though little is known about membrane changes during syntrophy. These interactions are also central to theories of eukaryogenesis, where a symbiosis between an archaeal host-likely an Asgard archaeon-and a bacterial partner may have arisen from prior syntrophic interactions. Model systems of syntrophic microbes provide valuable insights into how such intimate associations could have led to the emergence of eukaryotic life.  Here, we used syntrophic cocultures of the sulfate-reducing bacterium Desulfovibrio vulgaris and the methanogenic archaeon Methanococcus maripaludis to investigate membrane changes during a syntrophic interaction involving cell-to-cell contact. Evolved cocultures after several generations under syntrophic conditions were analyzed by proteomics and transcriptomics to identify differentially expressed proteins connected to cell-to-cell interactions, as well as by lipid analyses to determine changes in the cell membrane of both syntrophic partners.