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Thorarchaeota
"''Candidatus'' Thorarchaeota", or simply Thorarchaeota, is a phylum within the superphylum Asgard archaea. The Asgard superphylum represents the closest prokaryotic relatives of eukaryotes. Since there is such a close relation between the two different domains, it provides further evidence to the two-domain tree of life theory which states that eukaryotes branched from the archaeal domain. Asgard archaea are single cell marine microbes that contain branch-like appendages and have genes that are similar to eukarya. The asgard archaea superphylum is composed of Thorarchaeota, Lokiarchaeota, Odinarchaeota, and Heimdallarchaeota. Thorarchaeota were first identified from the sulfate-methane transition zone in tidewater sediments. Thorarcheota are widely distributed in marine and freshwater sediments. Discovery Thorarchaeota were discovered by analyzing estuary sediments obtained from the White Oak River in North Carolina. Estuaries are brackish bodies of water where fresh and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odinarchaeota
Promethearchaeati ( syn. "Asgard") is a kingdom belonging to the domain Archaea that contain eukaryotic signature proteins. It appears that the eukaryotes, the domain that contains the animals, plants, fungi and protists, emerged within the Promethearchaeati, in a branch containing the "''Candidatus'' Heimdallarchaeota". This supports the two-domain system of classification over the three-domain system. The kingdom contains one phylum Promethearchaeota, and it contains one valid class Promethearchaeia. After including the kingdom category into ICNP, the only validly published name of this group is kingdom Promethearchaeati. All formerly proposed "phyla" would be de-ranked to classes in this framework. Discovery and nomenclature In the summer of 2010, sediments were analysed from a gravity core taken in the rift valley on the Knipovich ridge in the Arctic Ocean, near the Loki's Castle hydrothermal vent site. Specific sediment horizons previously shown to contain high ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asgard (archaea)
Promethearchaeati (Synonym (taxonomy), syn. "Asgard") is a Kingdom (biology), kingdom belonging to the Domain (biology), domain Archaea that contain Eukaryote, eukaryotic signature proteins. It appears that the eukaryotes, the Domain (biology), domain that contains the animals, plants, Fungus, fungi and Protist, protists, Eukaryogenesis, emerged within the Promethearchaeati, in a branch containing the "''Candidatus'' Heimdallarchaeota". This supports the two-domain system of classification over the three-domain system. The kingdom contains one phylum Promethearchaeota, and it contains one valid Class (biology), class Promethearchaeia. After including the kingdom category into International Code of Nomenclature of Prokaryotes, ICNP, the only validly published name of this group is kingdom Promethearchaeati. All formerly proposed "phyla" would be de-ranked to classes in this framework. Discovery and nomenclature In the summer of 2010, sediments were analysed from a gravity Core s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea Cladistics, cladistically includes eukaryotes, the term "archaea" (: archaeon , from the Greek "ἀρχαῖον", which means ancient) in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially Taxonomy (biology), classified as bacteria, receiving the name archaebacteria (, in the Archaebacteria Kingdom (biology), kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from Bacteria and Eukaryote, Eukaryota. Archaea are further divided into multiple recognized phylum, phyla. Classification is difficult because most have not been Isolation (microbiology), isolated in a laboratory and have been detected only by their Gene, gene s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-domain System
The two-domain system is a biological classification by which all organisms in the tree of life are classified into two domains, Bacteria and Archaea. It emerged from development of knowledge of archaea diversity and challenges the widely accepted three-domain system that classifies life into Bacteria, Archaea, and Eukarya. It was preceded by the eocyte hypothesis of James A. Lake in the 1980s, which was largely superseded by the three-domain system, due to evidence at the time. Better understanding of archaea, especially of their roles in the origin of eukaryotes through symbiogenesis with bacteria, led to the revival of the eocyte hypothesis in the 2000s. The two-domain system became more widely accepted after the discovery of a large kingdom of archaea called Promethearchaeati in 2017, which evidence suggests to be the evolutionary root of eukaryotes, thereby making eukaryotes members of the domain Archaea. While the features of promethearchaea do not completely rule out th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Oak River
The White Oak River is a blackwater river, close to 48 mi (77 km) long, on the coastal plain of southeast North Carolina in the United States. It empties in the Atlantic Ocean. Course It rises in the White Oak Pocosin in northern Onslow County and southern Jones County approximately 15 mi (24 km) north of Jacksonville. It flows east, then SSE, along the border between Onslow, Jones and Carteret counties, and forming the western boundary of Croatan National Forest. The lower 10 mi (16 km) of the river is a tidal estuary, approximately 1.6 km wide. It enters the Atlantic at Bogue Sound, then passes between two barrier islands (Bogue Banks and Bear Island) through Bogue Inlet into the open Atlantic at Onslow Bay. Habitat The White Oak River runs through a variety of habitats including swamps, hardwood forests, and salt marsh flats. A wide variety of wildlife can be found in and around the river and its smaller river feeders. These creeks p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptidase
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life and viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms. Classification Based on catalytic residue Proteases can be classified into seven broad groups: * Serine proteases - using a serine alcohol * Cysteine protea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formate Dehydrogenase
Formate dehydrogenases are a set of enzymes that catalyse the oxidation of formate to carbon dioxide, donating the electrons to a second substrate, such as NAD+ in formate:NAD+ oxidoreductase () or to a cytochrome in formate:ferricytochrome-b1 oxidoreductase (). This family of enzymes has attracted attention as inspiration or guidance on methods for the carbon dioxide fixation, relevant to global warming. Function NAD-dependent formate dehydrogenases are important in methylotrophic yeast and bacteria, being vital in the catabolism of C1 compounds such as methanol. The cytochrome-dependent enzymes are more important in anaerobic metabolism in prokaryotes. For example, in '' E. coli'', the formate:ferricytochrome-b1 oxidoreductase is an intrinsic membrane protein with two subunits and is involved in anaerobic nitrate respiration. NAD-dependent reaction Formate + NAD+ CO2 + NADH + H+ Cytochrome-dependent reaction Formate + 2 ferricytochrome b1 CO2 + 2 ferrocytochrome b1 + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydromethanopterin
Tetrahydromethanopterin (THMPT, ) is a coenzyme in methanogenesis. It is the carrier of the C1 group as it is reduced to the methyl level, before transferring to the coenzyme M. Tetrahydrosarcinapterin (THSPT, ) is a modified form of THMPT, wherein a glutamyl group linked to the 2-hydroxy glutaric acid terminus. THMPT is the main platform for C1 transformations N-Formyl methanofuran donates the C1 group to the N5 site of the pterin to give the formyl- THMPT. The formyl group subsequently condenses intramolecularly to give methenyl-, which is then reduced to methylene-THMPT by 5,10-methenyl- hydrogenase with as the electron donor. Methylene- MPT is subsequently converted, using coenzyme F420 as the electron source, to methyl-THMPT, catalyzed by F420-dependent methylene-THMPT reductase. Methyl-THMPT is the methyl donor to coenzyme M, a conversion mediated by methyl-THMPT: coenzyme M methyltransferase. Comparison with tetrahydrofolic acid THMPT is related to the bette ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clostripain
Clostripain (, ''clostridiopeptidase B'', ''clostridium histolyticum proteinase B'', ''alpha-clostridipain'', ''clostridiopeptidase'', ''Endoproteinase Arg-C'') is a proteinase that cleaves proteins on the carboxyl peptide bond of arginine. It was isolated from ''Clostridium histolyticum''. The isoelectric point of the enzyme is 4.8-4.9 (at 8 °C), and optimum pH is 7.4~7.8 (against α-benzoyl-arginine ethyl ester). The composition of the enzyme is indicated to be of two chains of relative molecular mass 45,000 and 12,500. See also * Benzoyl * Ethyl ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distinct ... References External links * * EC 3.4.22 Post-translational modification {{hydrolase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gingipain
Gingipains are a family of proteases secreted by ''Porphyromonas gingivalis''. Among other functions, it works to degrade cytokines, thereby downregulating the host response in the form of reduced inflammation. Gingipain has been studied for its potential role in the development of Alzheimer's disease. See also * Gingipain R Gingipain R (, ''Arg-gingipain'', ''gingipain-1'', ''argingipain'', ''Arg-gingivain-55 proteinase'', ''Arg-gingivain-70 proteinase'', ''Arg-gingivain-75 proteinase'', ''arginine-specific cysteine protease'', ''arginine-specific gingipain'', ''argi ... * Gingipain K References {{Portal bar, Biology, border=no Proteases EC 3.4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candidatus
In prokaryote nomenclature, ''Candidatus'' (abbreviated ''Ca.''; Latin for "candidate of Roman office") is used to name prokaryotic taxa that are well characterized but yet- uncultured. Contemporary sequencing approaches, such as 16S ribosomal RNA sequencing or metagenomics, provide much information about the analyzed organisms and thus allow identification and characterization of individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in ''in vitro'' study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity. Nomenclature History The initial International Code of Nomenclature of Prokaryotes (ICNP) as well as early revisions did not account for the possibility of identifying prokaryotes which were not yet cultivable. This was in apparent conflict with the ICNP's stated scope, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycolysis
Glycolysis is the metabolic pathway that converts glucose () into pyruvic acid, pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The Thermodynamic free energy, free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and NADH, reduced nicotinamide adenine dinucleotide (NADH). Glycolysis is a sequence of ten reactions catalyzed by enzymes. The wide occurrence of glycolysis in other species indicates that it is an ancient metabolic pathway. Indeed, the reactions that make up glycolysis and its parallel pathway, the pentose phosphate pathway, can occur in the Great Oxygenation Event, oxygen-free conditions of the Archean oceans, also in the absence of enzymes, catalyzed by metal ions, meaning this is a plausible prebiotic pathway for abiogenesis. The most common type of glycolysis is the ''Embden–Meyerhof–Parnas (EMP) pathway'', which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
