Aeropyrum: A genus of anaerobic, chemolithotropic coccoid ARCHAEA, in the family DESULFUROCOCCACEAE. They live in marine environments.Desulfurococcaceae: A family of archaea, in the order DESULFUROCOCCALES, consisting of anaerobic cocci which utilize peptides, proteins or carbohydrates facultatively by sulfur respiration or fermentation. There are eight genera: AEROPYRUM, Desulfurococcus, Ignicoccus, Staphylothermus, Stetteria, Sulfophoboccus, Thermodiscus, and Thermosphaera. (From Bergey's Manual of Systematic Bacteriology, 2d ed)Crenarchaeota: A kingdom in the domain ARCHAEA comprised of thermoacidophilic, sulfur-dependent organisms. The two orders are SULFOLOBALES and THERMOPROTEALES.Archaeal Proteins: Proteins found in any species of archaeon.RNA, Transfer, Thr: A transfer RNA which is specific for carrying threonine to sites on the ribosomes in preparation for protein synthesis.Thermoproteaceae: A family of THERMOPROTEALES consisting of variable length rigid rods without septa. They grow either chemolithoautotrophically or by sulfur respiration. The four genera are: PYROBACULUM; THERMOPROTEUS; Caldivirga; and Thermocladium. (From Bergey's Manual of Systematic Bacteriology, 2d ed)DNA, Archaeal: Deoxyribonucleic acid that makes up the genetic material of archaea.Genome, Archaeal: The genetic complement of an archaeal organism (ARCHAEA) as represented in its DNA.Hydrothermal Vents: Hot springs on the ocean floor. They are commonly found near volcanically active places such as mid-oceanic ridges.Archaea: One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.Group II Chaperonins: A subcategory of chaperonins found in ARCHAEA and the CYTOSOL of eukaryotic cells. Group II chaperonins form a barrel-shaped macromolecular structure that is distinct from GROUP I CHAPERONINS in that it does not utilize a separate lid like structure to enclose proteins.RNA, Archaeal: Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.Threonine-tRNA Ligase: An enzyme that activates threonine with its specific transfer RNA. EC Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Archaeal Viruses: Viruses whose hosts are in the domain ARCHAEA.Proline Oxidase: The first enzyme of the proline degradative pathway. It catalyzes the oxidation of proline to pyrroline-5-carboxylic acid in the presence of oxygen and water. The action is not reversible. The specific activity of proline oxidase increases with age. EC 1.5.3.-.