title: Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria.
abstract: We present evidence for a dimorphic life cycle in the vacuolate sulfide-oxidizing bacteria that appears to involve the attachment of a spherical Thiomargarita-like cell to the exteriors of invertebrate integuments and other benthic substrates at methane seeps. The attached cell elongates to produce a stalk-like form before budding off spherical daughter cells resembling free-living Thiomargarita that are abundant in surrounding sulfidic seep sediments. The relationship between the attached parent cell and free-living daughter cell is reminiscent of the dimorphic life modes of the prosthecate Alphaproteobacteria, but on a grand scale, with individual elongate cells reaching nearly a millimeter in length. Abundant growth of attached Thiomargarita-like bacteria on the integuments of gastropods and other seep fauna provides not only a novel ecological niche for these giant bacteria, but also for animals that may benefit from epibiont colonization.
authors.affiliation: Department of Earth Sciences, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USA. baileyj@umn.edu
authors.forename: Jake V
authors.initials: JV
authors.lastname: Bailey
authors.forename: Verena
authors.initials: V
authors.lastname: Salman
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Rouse
authors.forename: Heide N
authors.initials: HN
authors.lastname: Schulz-Vogt
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Levin
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Orphan
mesh_terms: D003364:Costa Rica; D060146:Ecotype; D019015:Geologic Sediments / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013440:Sulfides / Q000378:metabolism; D041962:Thiotrichaceae / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification
chemical_list: D013440:Sulfides; D008697:Methane