title: Isolation of extremely thermophilic sulfate reducers: evidence for a novel branch of archaebacteria.
abstract: Extremely thermophilic archaebacteria are known to be metabolizers of elemental sulfur and the methanogens. A novel group of extremely thermophilic archaebacteria is described, which consists of sulfate-respiring organisms that contain pure factor 420 and that have been isolated from marine hydrothermal systems in Italy. They possess a third type of archaebacterial RNA polymerase structure previously unknown, indicating an exceptional phylogenetic position. Most likely, this group represents a third major branch within the archaebacteria. The existence of sulfate reducers at extremely high temperatures could explain hydrogen sulfide formation in hot sulfate-containing environments, such as submarine hydrothermal systems and deep oil wells.
authors.forename: K O
authors.initials: KO
authors.lastname: Stetter
authors.forename: G
authors.initials: G
authors.lastname: Lauerer
authors.forename: M
authors.initials: M
authors.lastname: Thomm
authors.forename: A
authors.initials: A
authors.lastname: Neuner