title: Endosymbiotic sulphate-reducing and sulphide-oxidizing bacteria in an oligochaete worm.
abstract: Stable associations of more than one species of symbiont within a single host cell or tissue are assumed to be rare in metazoans because competition for space and resources between symbionts can be detrimental to the host. In animals with multiple endosymbionts, such as mussels from deep-sea hydrothermal vents and reef-building corals, the costs of competition between the symbionts are outweighed by the ecological and physiological flexibility gained by the hosts. A further option for the coexistence of multiple symbionts within a host is if these benefit directly from one another, but such symbioses have not been previously described. Here we show that in the gutless marine oligochaete Olavius algarvensis, endosymbiotic sulphate-reducing bacteria produce sulphide that can serve as an energy source for sulphide-oxidizing symbionts of the host. Thus, these symbionts do not compete for resources but rather share a mutalistic relationship with each other in an endosymbiotic sulphur cycle, in addition to their symbiotic relationship with the oligochaete host.
authors.affiliation: Max Planck Institute of Marine Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany. ndubilie@mpi-bremen.de
authors.forename: N
authors.initials: N
authors.lastname: Dubilier
authors.forename: C
authors.initials: C
authors.lastname: Mülders
authors.forename: T
authors.initials: T
authors.lastname: Ferdelman
authors.forename: D
authors.initials: D
authors.lastname: de Beer
authors.forename: A
authors.initials: A
authors.lastname: Pernthaler
authors.forename: M
authors.initials: M
authors.lastname: Klein
authors.forename: M
authors.initials: M
authors.lastname: Wagner
authors.forename: C
authors.initials: C
authors.lastname: Erséus
authors.forename: F
authors.initials: F
authors.lastname: Thiermann
authors.forename: J
authors.initials: J
authors.lastname: Krieger
authors.forename: O
authors.initials: O
authors.lastname: Giere
authors.forename: R
authors.initials: R
authors.lastname: Amann
mesh_terms: D000332:Aerobiosis; D000362:Agar; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D020564:Deltaproteobacteria / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D020563:Gammaproteobacteria / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D017404:In Situ Hybridization, Fluorescence; D007700:Kinetics; D016013:Likelihood Functions; D008854:Microscopy, Electron; D008954:Models, Biological; D008969:Molecular Sequence Data; D009835:Oligochaeta / Q000382:microbiology* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012822:Silicon Dioxide; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism; D013559:Symbiosis
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D013440:Sulfides; D002245:Carbon Dioxide; D013455:Sulfur; D012822:Silicon Dioxide; D000362:Agar