title: Sticking together: inter-species aggregation of bacteria isolated from iron snow is controlled by chemical signaling.
abstract: Marine and lake snow is a continuous shower of mixed organic and inorganic aggregates falling from the upper water where primary production is substantial. These pelagic aggregates provide a niche for microbes that can exploit these physical structures and resources for growth, thus are local hot spots for microbial activity. However, processes underlying their formation remain unknown. Here, we investigated the role of chemical signaling between two co-occurring bacteria that each make up more than 10% of the community in iron-rich lakes aggregates (iron snow). The filamentous iron-oxidizing Acidithrix strain showed increased rates of Fe(II) oxidation when incubated with cell-free supernatant of the heterotrophic iron-reducing Acidiphilium strain. Amendment of Acidithrix supernatant to motile cells of Acidiphilium triggered formation of cell aggregates displaying similar morphology to those of iron snow. Comparative metabolomics enabled the identification of the aggregation-inducing signal, 2-phenethylamine, which also induced faster growth of Acidiphilium. We propose a model that shows rapid iron snow formation, and ultimately energy transfer from the photic zone to deeper water layers, is controlled via a chemically mediated interplay.
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Jiro F
authors.identifier: 0000-0002-3311-1511
authors.initials: JF
authors.lastname: Mori
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Ueberschaar
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.|The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
authors.forename: Shipeng
authors.initials: S
authors.lastname: Lu
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Cooper
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Pohnert
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.|The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Küsel
mesh_terms: D041801:Acidiphilium / Q000302:isolation & purification / Q000378:metabolism*; D039903:Actinobacteria / Q000302:isolation & purification / Q000378:metabolism*; D001419:Bacteria / Q000302:isolation & purification; D005296:Ferrous Compounds / Q000378:metabolism*; D007501:Iron / Q000032:analysis; D060106:Lakes / Q000737:chemistry / Q000382:microbiology*; D056265:Microbial Interactions; D010084:Oxidation-Reduction; D010627:Phenethylamines / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D005296:Ferrous Compounds; D010627:Phenethylamines; C029261:phenethylamine; D007501:Iron