Methanobacteriaceae: A family of anaerobic, coccoid to rod-shaped METHANOBACTERIALES. Cell membranes are composed mainly of polyisoprenoid hydrocarbons ether-linked to glycerol. Its organisms are found in anaerobic habitats throughout nature.Methane: The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)WyomingHot Springs: Habitat of hot water naturally heated by underlying geologic processes. Surface hot springs have been used for BALNEOLOGY. Underwater hot springs are called HYDROTHERMAL VENTS.Wolves: Any of several large carnivorous mammals of the family CANIDAE that usually hunt in packs.Bison: A genus of the family Bovidae having two species: B. bison and B. bonasus. This concept is differentiated from BUFFALOES, which refers to Bubalus arnee and Syncerus caffer.Sulfolobales: An order of CRENARCHAEOTA consisting of aerobic or facultatively aerobic, chemolithotrophic cocci which are extreme thermoacidophiles. They lack peptidoglycan in their cell walls.MontanaArchaeal Viruses: Viruses whose hosts are in the domain ARCHAEA.Methanomicrobiales: An order of anaerobic, highly specialized methanogens, in the kingdom EURYARCHAEOTA. Its organisms are nonmotile or motile, with cells occurring as coccoid bodies, pseudosarcina, or rods. Families include METHANOMICROBIACEAE, Methanocorpusculaceae, and Methanospirillaceae.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Clustered Regularly Interspaced Short Palindromic Repeats: Repetitive nucleic acid sequences that are principal components of the archaeal and bacterial CRISPR-CAS SYSTEMS, which function as adaptive antiviral defense systems.DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.Methanobacterium: A genus of anaerobic, rod-shaped METHANOBACTERIACEAE. Its organisms are nonmotile and use ammonia as the sole source of nitrogen. These methanogens are found in aquatic sediments, soil, sewage, and the gastrointestinal tract of animals.DenmarkGeologic Sediments: A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)Euryarchaeota: A phylum of ARCHAEA comprising at least seven classes: Methanobacteria, Methanococci, Halobacteria (extreme halophiles), Archaeoglobi (sulfate-reducing species), Methanopyri, and the thermophiles: Thermoplasmata, and Thermococci.Niemann-Pick Disease, Type A: The classic infantile form of Niemann-Pick Disease, caused by mutation in SPHINGOMYELIN PHOSPHODIESTERASE. It is characterized by accumulation of SPHINGOMYELINS in the cells of the MONONUCLEAR PHAGOCYTE SYSTEM and other cell throughout the body leading to cell death. Clinical signs include JAUNDICE, hepatosplenomegaly, and severe brain damage.Argininosuccinate Lyase: An enzyme of the urea cycle which splits argininosuccinate to fumarate plus arginine. Its absence leads to the metabolic disease ARGININOSUCCINIC ACIDURIA in man. EC A genus of gram-positive, anaerobic, cocci to short rod-shaped ARCHAEA, in the family METHANOBACTERIACEAE, order METHANOBACTERIALES. They are found in the GASTROINTESTINAL TRACT or other anoxic environments.Methanobacteriales: An order of anaerobic, coccoid to rod-shaped methanogens, in the kingdom EURYARCHAEOTA. They are nonmotile, do not catabolize carbohydrates, proteinaceous material, or organic compounds other than formate or carbon monoxide, and are widely distributed in nature.Argininosuccinate Synthase: An enzyme of the urea cycle that catalyzes the formation of argininosuccinic acid from citrulline and aspartic acid in the presence of ATP. Absence or deficiency of this enzyme causes the metabolic disease CITRULLINEMIA in humans. EC, Protein: Databases containing information about PROTEINS such as AMINO ACID SEQUENCE; PROTEIN CONFORMATION; and other properties.Thiosulfate Sulfurtransferase: An enzyme that catalyzes the transfer of the planetary sulfur atom of thiosulfate ion to cyanide ion to form thiocyanate ion. EC 3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.Thiouridine: A photoactivable URIDINE analog that is used as an affinity label.Sulfurtransferases: Enzymes which transfer sulfur atoms to various acceptor molecules. EC 2.8.1.Hydrogen: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.Carbon Cycle: The cycle by which the element carbon is exchanged between organic matter and the earth's physical environment.Gases: The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)Alcohol Dehydrogenase: A zinc-containing enzyme which oxidizes primary and secondary alcohols or hemiacetals in the presence of NAD. In alcoholic fermentation, it catalyzes the final step of reducing an aldehyde to an alcohol in the presence of NADH and hydrogen.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.DNA, Archaeal: Deoxyribonucleic acid that makes up the genetic material of archaea.Antigens, Archaeal: Substances of archaeal origin that have antigenic activity.Biohazard Release: Uncontrolled release of biological material from its containment. This either threatens to, or does, cause exposure to a biological hazard. Such an incident may occur accidentally or deliberately.Archaeal Proteins: Proteins found in any species of archaeon.Oil and Gas Fields: Areas of the earth where hydrocarbon deposits of PETROLEUM and/or NATURAL GAS are located.Containment of Biohazards: Provision of physical and biological barriers to the dissemination of potentially hazardous biologically active agents (bacteria, viruses, recombinant DNA, etc.). Physical containment involves the use of special equipment, facilities, and procedures to prevent the escape of the agent. Biological containment includes use of immune personnel and the selection of agents and hosts that will minimize the risk should the agent escape the containment facility.Gene Expression Regulation, Archaeal: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in archaea.Sperm Whale: The species Physeter catodon (also called Physeter macrocephalus), in the family Physeteridae. The common name is derived from the milky wax substance in its head (spermaceti). The species also produces an intestinal secretion AMBERGRIS, which was previously used in perfumes. The sperm whale is the largest toothed MAMMAL in the world.Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Islands: Tracts of land completely surrounded by water.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Oceanospirillaceae: A family of gram-negative bacteria in the order Oceanospirillales.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Adenoma: A benign epithelial tumor with a glandular organization.Colorectal Neoplasms: Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.Microbiota: The full collection of microbes (bacteria, fungi, virus, etc.) that naturally exist within a particular biological niche such as an organism, soil, a body of water, etc.Metagenome: A collective genome representative of the many organisms, primarily microorganisms, existing in a community.Gastrointestinal Tract: Generally refers to the digestive structures stretching from the MOUTH to ANUS, but does not include the accessory glandular organs (LIVER; BILIARY TRACT; PANCREAS).Metabolome: The dynamic collection of metabolites which represent a cell's or organism's net metabolic response to current conditions.