Query: NC_015474:1216971 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_006396:2625962 Haloarcula marismortui ATCC 43049 chromosome I, complete sequence
Lineage: Haloarcula marismortui; Haloarcula; Halobacteriaceae; Halobacteriales; Euryarchaeota; Archaea
General Information: This organism was isolated from the Dead Sea and will provide information on the proteins necessary for adaptation to a high salt environment. Halophilic archaeon. Halobacterial species are obligately halophilic microorganisms that have adapted to optimal growth under conditions of extremely high salinity 10 times that of sea water. They contain a correspondingly high concentration of salts internally and exhibit a variety of unusual and unique molecular characteristics. Since their discovery, extreme halophiles have been studied extensively by chemists, biochemists, microbiologists, and molecular biologists to define both molecular diversity and universal features of life. A notable list of early research milestones on halophiles includes the discovery of a cell envelope composed of an S-layer glycoprotein, archaeol ether lipids and purple membrane, and metabolic and biosynthetic processes operating at saturating salinities. These early discoveries established the value of investigations directed at extremophiles and set the stage for pioneering phylogenetic studies leading to the three-domain view of life and classification of Halobacterium as a member of the archaeal domain. This organism is also know as "Halobacterium of the Dead Sea". Growth occurs in 1.7-5.1 M NaCl with optimum salt concentration of 3.4-3.9 M NaCl. The cytosol of this organism is a supersaturated salt solution in which proteins are soluble and active. This halophile is chemoorganotrophic and able to use a wide variety of compounds as sole carbon and energy sources.