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Glycerol Dialkyl Glycerol Tetraether
Glycerol dialkyl glycerol tetraether lipids (GDGTs) are a class of membrane lipids synthesized by archaea and some bacteria, making them useful biomarkers for these organisms in the geological record. Their presence, structure, and relative abundances in natural materials can be useful as proxies for temperature, terrestrial organic matter input, and soil pH for past periods in Earth history. Some structural forms of GDGT form the basis for the TEX86 paleothermometer. Isoprenoid GDGTs, now known to be synthesized by many archaeal classes, were first discovered in Extremophile, extremophilic archaea cultures. Branched GDGTs, likely synthesized by acidobacteriota, were first discovered in a natural Dutch peat sample in 2000. The phospholipid built from a two-headed tetraether lipid is often called a bolalipid. In a membrane bilayer, a bolalipid can appear in a straight "O-shape" conformation where it spans both sides, or appear in a U-shaped conformation where its two phosphate heads ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldarchaeol Linear
Caldarchaeol is a membrane-spanning lipid of the isoprenoid glycerol dialkyl glycerol tetraether ( iGDGT) class, produced and used by archaea. Membranes made up of caldarchaeol are more stable since the hydrophobic chains are linked together (as compared to lipid bilayer structures in eukaryotes and bacteria), allowing archaea to withstand extreme conditions. Chemical Structure Caldarchaeol is also known as dibiphytanyl diglycerol tetraether, or GDGT-0. Two glycerol units are linked together by two biphytanes, each of which consist of two phytanes linked together to form a linear chain of 32 carbon atoms (40 carbons including methyl branches). The configuration of the macrocyclic tetraether has been determined by total synthesis of the C40-diol and comparison with a sample obtained by degradation of natural tetraether. A synthesis of tetraether has also been carried out. Caldarchaeol is not currently described as having any hazards. Due to its high molecular weight, it is n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrososphaerota
The Nitrososphaerota (syn. Thaumarchaeota) are a phylum of the Archaea proposed in 2008 after the genome of '' Cenarchaeum symbiosum'' was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota (formerly Crenarchaeota). Three described species in addition to ''C. symbiosum'' are '' Nitrosopumilus maritimus'', '' Nitrososphaera viennensis'', and '' Nitrososphaera gargensis''. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea '' Nitrosopumilus maritimus'' and '' Nitrososphaera gargensis'', concluding that these species form a distinct lineage that includes ''Cenarchaeum symbiosum''. The lipid crenarchaeol has been fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanopyrus Kandleri
''Methanopyrus'' is a genus of methanogen, with a single described species, ''Methanopyrus kandleri''. It is a rod-shaped hyperthermophile, discovered on the wall of a black smoker from the Gulf of California at a depth of 2,000 m, at temperatures of 84–110 °C. Strain 116 was discovered in black smoker fluid of the Kairei hydrothermal field; it can survive and reproduce at 122 °C. ''M. kandleri'' also requires a high ionic concentration (>1 M) in order for growth and cellular activity. Due to the species' high resilience and extreme environment, ''M. kandleri'' is also classified as an extremophile. It lives in a hydrogen–carbon dioxide rich environment, and like other methanogens reduces the latter to methane. It is placed among the Euryarchaeota, in its own class. Microbiological characteristics Morphology ''Methanopyrus kandleri'' is a rod-shaped methanogen with an approximate length of 2–14 μm and diameter of 0.5 μm. The cellular membr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biphytane
Biphytane (or bisphytane) is a C40 Terpenoid, isoprenoid produced from glycerol dialkyl glycerol tetraether (GDGT) degradation. As a common lipid membrane component, biphytane is widely used as a biomarker for archaea. In particular, given its association with sites of active anaerobic oxidation of methane (AOM), it is considered a biomarker of methanotrophic archaea. It has been found in both marine and terrestrial environments. Chemical structure Glycerol dialkyl glycerol tetraethers (GDGT) are major membrane lipids synthesized by archaea and some bacteria. In particular, isoprenoid GDGTs are characterized by isoprenoid carbon chains connected to the glycerol molecules by ether bonds. Biphytane is produced by the chemical cleavage of the ether bonds within isoprenoid GDGT (GDGT-0). It is composed of isoprene units bound by ether bonds with six isoprene units (or two phytanes) linked together by a head-to-head linkage.Peters, Kenneth E., Clifford C. Walters, and J. Michael Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldarchaeol
Caldarchaeol is a membrane-spanning lipid of the Terpenoid, isoprenoid glycerol dialkyl glycerol tetraether (Glycerol dialkyl glycerol tetraether, iGDGT) class, produced and used by archaea. Membranes made up of caldarchaeol are more stable since the Hydrophobe, hydrophobic chains are linked together (as compared to lipid bilayer structures in Eukaryote, eukaryotes and bacteria), allowing archaea to withstand extreme conditions. Chemical Structure Caldarchaeol is also known as dibiphytanyl diglycerol tetraether, or GDGT-0. Two glycerol units are linked together by two biphytanes, each of which consist of two phytanes linked together to form a linear chain of 32 carbon atoms (40 carbons including methyl branches). The Cahn–Ingold–Prelog priority rules, configuration of the macrocyclic tetraether has been determined by total synthesis of the C40-diol and comparison with a sample obtained by degradation of natural tetraether. A synthesis of tetraether has also been carried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanotroph
Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to survive. Methanotrophs are especially common in or near environments where methane is produced, although some methanotrophs can oxidize atmospheric methane. Their habitats include wetlands, soils, marshes, rice paddies, landfills, aquatic systems (lakes, oceans, streams) and more. They are of special interest to researchers studying global warming, as they play a significant role in the global methane budget, by reducing the amount of methane emitted to the atmosphere. Methanotrophy is a special case of methylotrophy, using single-carbon compounds that are more reduced than carbon dioxide. Some methylotrophs, however, can also make use of multi-carbon compounds; this differentiates them from methanotrophs, which are usually fastidious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaerobic Methane Oxidation
Anaerobic oxidation of methane (AOM) is a methane-consuming microbial process occurring in anoxic marine and freshwater sediments. AOM is known to occur among mesophiles, but also in psychrophiles, thermophiles, halophiles, acidophiles, and alkophiles. During AOM, methane is oxidized with different terminal electron acceptors such as sulfate, nitrate, nitrite and metals, either alone or in syntrophy with a partner organism. Coupled to sulfate reduction The overall reaction is: :CH4 + SO42− → HCO3− + HS− + H2O Sulfate-driven AOM is mediated by a syntrophic consortium of methanotrophic archaea and sulfate-reducing bacteria. They often form small aggregates or sometimes voluminous mats. The archaeal partner is abbreviated ANME, which stands for "anaerobic methanotroph". ANME's are very closely related to methanogenic archaea and recent investigations suggest that AOM is an enzymatic reversal of methanogenesis. It is still poorly understood how the syntrophic partners inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Isotope
Carbon (6C) has 14 known isotopes, from to as well as , of which only and are stable. The longest-lived radioisotope is , with a half-life of years. This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reaction + → + . The most stable artificial radioisotope is , which has a half-life of . All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. The least stable isotope is , with a half-life of . Light isotopes tend to decay into isotopes of boron and heavy ones tend to decay into isotopes of nitrogen. List of isotopes , -id=Carbon-8 , , style="text-align:right" , 6 , style="text-align:right" , 2 , , [] , proton emission, 2p , Also immediately emits two protons for the net reaction of → + 4 , 0+ , , , -id=Carbon-9 , rowspan=3, , rowspan=3 style="text-align:right" , 6 , rowspan=3 style="text-align:right" , 3 , rowspan=3, , rowspan=3, , � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korarchaeota
The Korarchaeota is a proposed phylum within the Archaea. The name is derived from the Greek noun koros or kore, meaning ''young man'' or ''young woman,'' and the Greek adjective archaios which means ''ancient.'' They are also known as Xenarchaeota. The name is equivalent to ''Candidatus'' Korarchaeota, and they go by the name Xenarchaeota or Xenarchaea as well. Taxonomy The Korarchaeota are a proposed phylum in the domain, Archaea. They are thought to have diverged relatively early in the genesis of Archaea and are among the deep-branching lineages. Korarchaeota are also known as Xenarchaeota. Korarchaeaota, along with Thaumarchaeota, Aigarchaeota, Crenarchaeota, belong to the superphylum called TACK. The evolutionary link between Asgard archaea and Korarchaeota of TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, Korarchaeota) is yet unknown. The first member of Korarchaeota to have its genome reconstructed was ''Korarchaeum crypotfilum'', which was found in a hot spring in Ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euryarchaeota
Methanobacteriota is a phylum in the domain Archaea. Taxonomy The phylum ''Methanobacteriota'' was introduced to prokaryotic nomenclature in 2023. It contains following classes: *Archaeoglobi Garrity & Holt (2002) *Halobacteria Grant ''et al.'' (2002) *Methanobacteria Boone (2002) (contains type genus ''Methanobacterium'') *Methanococci Boone (2002) *Methanonatronarchaeia Sorokin ''et al.'' (2018) *Methanopyri Garrity & Holt (2002) *Methanosarcinia Chuvochina ''et al.'' (2024) *Thermococci Zillig & Reysenbach (2002) *Thermoplasmata Reysenbach (2002) References Archaea phyla {{Archaea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoproteota
The Thermoproteota are prokaryotes that have been classified as a phylum (biology), phylum of the domain Archaea. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteristic Thermoproteota environmental rRNA indicating the organisms may be the most abundant archaea in the marine environment. Originally, they were separated from the other archaea based on rRNA sequences; other physiological features, such as lack of histones, have supported this division, although some crenarchaea were found to have histones. Until 2005 all cultured Thermoproteota had been thermophilic or hyperthermophilic organisms, some of which have the ability to grow at up to 113 °C. These organisms stain Gram negative and are morphologically diverse, having rod, cocci, Filamentation, filamentous and oddly-shaped cells. Recent evidence shows that some members of the Thermoproteota are methanogens. Thermoproteota were initially classif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesophile
A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37 °C (about 99 °F). The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eucarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Oxygen requirements for mesophiles can be aerobic or anaerobic. There are three basic shapes of mesophiles: coccus, bacillus, and spiral. Habitat The habitats of mesophiles can include cheese and yogurt. They are often included during fermentation of beer and wine making. Since normal human body temperature is 37 °C, the majority of human pathogens are mesophiles, as are most of the organisms comprising the human microbiome. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
