title: Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation.
abstract: Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [(14)C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life.
authors.affiliation: 1] Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy [2].
authors.forename: Michail M
authors.initials: MM
authors.lastname: Yakimov
authors.affiliation: 1] Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy [2].
authors.forename: Violetta
authors.initials: V
authors.lastname: La Cono
authors.affiliation: 1] Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33136 [2].
authors.forename: Vladlen Z
authors.initials: VZ
authors.lastname: Slepak
authors.affiliation: Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy.
authors.forename: Gina
authors.initials: G
authors.lastname: La Spada
authors.affiliation: Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Arcadi
authors.affiliation: Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Messina
authors.affiliation: Institute for Marine Sciences, ISMAR-CNR, Forte S.Teresa, 19136 Pozzuolo di Lerici, La Spezia, Italy.
authors.forename: Mireno
authors.initials: M
authors.lastname: Borghini
authors.affiliation: Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy.
authors.forename: Luis S
authors.initials: LS
authors.lastname: Monticelli
authors.affiliation: Center for Metabolomics and Bioanalysis, University CEU San Pablo, Boadilla del Monte, 28668 Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Rojo
authors.affiliation: Center for Metabolomics and Bioanalysis, University CEU San Pablo, Boadilla del Monte, 28668 Madrid, Spain.
authors.forename: Coral
authors.initials: C
authors.lastname: Barbas
authors.affiliation: School of Biological Sciences, Bangor University, ECW Bldg Deiniol Rd, Bangor, Gwynedd LL57 2UW, UK.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Golyshina
authors.affiliation: 1] Institute of Catalysis, CSIC, Marie Curie 2, 28049 Madrid, Spain [2].
authors.forename: Manuel
authors.initials: M
authors.lastname: Ferrer
authors.affiliation: 1] School of Biological Sciences, Bangor University, ECW Bldg Deiniol Rd, Bangor, Gwynedd LL57 2UW, UK [2].
authors.forename: Peter N
authors.initials: PN
authors.lastname: Golyshin
authors.affiliation: 1] Institute for Coastal Marine Environment, CNR, Spianata S.Raineri 86, 98122 Messina, Italy [2] Mediterranean Science Commission (CIESM), 16 bd de Suisse, MC 98000, Monaco.
authors.forename: Laura
authors.initials: L
authors.lastname: Giuliano
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001622:Betaine / Q000378:metabolism / Q000494:pharmacology; D001639:Bicarbonates / Q000737:chemistry; D044822:Biodiversity; D017753:Ecosystem; D020565:Epsilonproteobacteria; D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016931:Halobacteriales / Q000145:classification / Q000235:genetics / Q000378:metabolism; D060106:Lakes / Q000382:microbiology*; D019083:Mediterranean Region; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012462:Saline Solution, Hypertonic; D055049:Salt Tolerance; D012623:Seawater / Q000737:chemistry; D012965:Sodium Chloride; D014871:Water Microbiology
chemical_list: D001639:Bicarbonates; D012336:RNA, Ribosomal, 16S; D012462:Saline Solution, Hypertonic; D001622:Betaine; D012965:Sodium Chloride