Query: NC_015474:644552 Pyrococcus sp. NA2 chromosome, complete genome
Lineage: Pyrococcus; Pyrococcus; Thermococcaceae; Thermococcales; Euryarchaeota; Archaea
General Information: Pyrococcus has similar characteristics of other thermoautotrophican archaea such as Archaeoglobus, and Methanococcus in the respect that they are all thermophilic and anaerobic. Pyrococcus differs, however, because its optimal growth temperature is nearly 100 °C and dwells at a greater sea depth than the other archaea. Studying Pyrococcus helps give insight to possible mechanisms used to endure extreme environmental conditions like high temperatures and high pressure.
Subject: NC_000917:1778173 Archaeoglobus fulgidus DSM 4304, complete genome
Lineage: Archaeoglobus fulgidus; Archaeoglobus; Archaeoglobaceae; Archaeoglobales; Euryarchaeota; Archaea
General Information: This is the type strain (DSM 4304) of the Archaeoglobales, and was isolated from a geothermally heated sea floor at Vulcano Island, Italy. Doubling time is four hours under optimal conditions. The organism is an autotrophic or organotrophic sulfate/sulfite respirer. An additional distinguishing characteristic is blue-green fluorescence at 420 nm. This bacterium is the first sulfur-metabolizing organism to have its genome sequence determined. Growth by sulfate reduction is restricted to relatively few groups of prokaryotes; all but one of these are Eubacteria, the exception being the archaeal sulfate reducers in the Archaeoglobales. These organisms are unique in that they are only distantly related to other bacterial sulfate reducers, and because they can grow at extremely high temperatures. The known Archaeoglobales are strict anaerobes, most of which are hyperthermophilic marine sulfate reducers found in hydrothermal environments. High-temperature sulfate reduction by Archaeoglobus species contributes to deep subsurface oil-well 'souring' by iron sulfide, which causes corrosion of iron and steel in oil-and gas-processing systems.