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| Pyrobaculum | |
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| Genus: | Pyrobaculum Huber, Kristjansson & Stetter 1988 |
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| Pyrobaculum islandicum Huber, Kristjansson & Stetter 1988 | |
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Pyrobaculum is a genus of the Thermoproteaceae.
As its Latin name Pyrobaculum (the "fire stick") suggests, the archaeon is rod-shaped and isolated from locations with high temperatures. It is Gram-negative and its cells are surrounded by an S-layer of protein subunits.
P. aerophilum is a hyperthermophilic and metabolically versatile organism. Different from other hyperthermophiles, it can live in the presence of oxygen and grows efficiently in microaerobic conditions.
Pyrobaculum yellowstonensis strain WP30 was obtained from an elemental sulfur sediment (Joseph's Coat Hot Spring [JCHS], 80 °C, pH 6.1, 135 μM As) in Yellowstone National Park (YNP), USA and is a chemoorganoheterotroph and requires elemental sulfur and/or arsenate as an electron acceptor. Growth in the presence of elemental sulfur and arsenate resulted in the formation of thioarsenates and polysulfides. The complete genome of this organism was sequenced (1.99 Mb, 58% G+C content), revealing numerous metabolic pathways for the degradation of carbohydrates, amino acids, and lipids. Multiple dimethyl sulfoxide-molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, were identified. Pathways for the de novo synthesis of nearly all required cofactors and metabolites were identified. The comparative genomics of P. yellowstonensis and the assembled metagenome sequence from JCHS showed that this organism is highly related (~95% average nucleotide sequence identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide an important foundation for developing an understanding of the distribution and function of these populations in YNP.
The first Pyrobaculum species to be sequenced was P. aerophilum. Its circular genome sequence is 2,222,430 Bp in length and contains 2605 protein-encoding sequences (CDS).
Under anaerobic conditions, the archaeon reduces nitrate to molecular nitrogen via the denitrification pathway. Most species grow either chemolithoautotrophically by sulfur reduction or organotrophically by sulfur respiration or by fermentation. Cells are rod-shaped with almost rectangular ends and are about 1.5–8 * 0.5–0.6 µm. Pyrobaculum is motile because of peritrichous or bipolar polytrichous flagellation, and its colonies are round and grey to greenish black. The species are either faculatively aerobic or strictly anaerobic. The growth was observed on yeast extract, peptone, extract of meat, but not on galactose, glucose, maltose, starch glycogen, ethanol, methanol, formamide, formate, malate, propionate, lactate, acetate, and casamino acids.
The first of the Pyrobaculum species to be genetically sequenced, P. aerophilum (rod-shaped, 3–8 * 0.6 µm), has a rare characteristic for an archaeon because it is capable of aerobic respiration (aerophilum = "air-loving"). This is evident from the fact that the archaeon grew only in the presence of oxygen when nitrate was absent. It produces colonies that are round and greyish yellow. It utilizes both organic (maximal cell densities were observed with complex organics such as yeast extract, meat extract, tryptone, and peptone as substrates) and inorganic compounds during aerobic and anaerobic respiration. Also, use of elemental sulphur for growth was observed. Further, P. aerophilum grows between 75 and 104 °C with an optimal growth temperature at 100 °C.
In stationary phase cultures, Pyrobaculum calidifontis cells were observed to aggregate. [1] The aggregation is likely to be mediated by archaeal bundling pili (ABP), which assemble into highly ordered bipolar bundles. [2] The bipolar nature of these bundles most likely arises from the association of filaments from at least two or more different cells. The component protein, AbpA, shows homology, both at the sequence and structural level, to the bacterial protein TasA, a major component of the extracellular matrix in bacterial biofilms, contributing to biofilm stability. [2]
To this date, the strains of Pyrobaculum have been isolated from neutral to slightly alkaline boiling solfataric waters and shallow marine hydrothermal systems. P. aerophilum was isolated from a boiling marine water hole at Maronti Beach, Ischia, Italy. Further studies show that P. aerophilum grows under strictly anaerobic conditions with nitrate as the electron acceptor. [3]
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [4] and National Center for Biotechnology Information (NCBI) [3]
| 16S rRNA based LTP_06_2022 [5] [6] [7] | 53 marker proteins based GTDB 08-RS214 [8] [9] [10] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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The Thermoproteota are prokaryotes that have been classified as a phylum of the Archaea domain. 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 recently 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, filamentous and oddly-shaped cells.
Archaeoglobus is a genus of the phylum Euryarchaeota. Archaeoglobus can be found in high-temperature oil fields where they may contribute to oil field souring.
Sulfolobus is a genus of microorganism in the family Sulfolobaceae. It belongs to the archaea domain.
Pyrococcus furiosus is a heterotrophic, strictly anaerobic, extremophilic, model species of archaea. It is classified as a hyperthermophile because it thrives best under extremely high temperatures, and is notable for having an optimum growth temperature of 100 °C. P. furiosus belongs to the Pyrococcus genus, most commonly found in extreme environmental conditions of hydrothermal vents. It is one of the few prokaryotic organisms that has enzymes containing tungsten, an element rarely found in biological molecules.
Thermoproteus is a genus of archaeans in the family Thermoproteaceae. These prokaryotes are thermophilic sulphur-dependent organisms related to the genera Sulfolobus, Pyrodictium and Desulfurococcus. They are hydrogen-sulphur autotrophs and can grow at temperatures of up to 95 °C.
Thermoproteales are an order of archaeans in the class Thermoprotei. They are the only organisms known to lack the SSB proteins, instead possessing the protein ThermoDBP that has displaced them. The rRNA genes of these organisms contain multiple introns, which can be homing endonuclease encoding genes, and their presence can impact the binding of "universal" 16S rRNA primers often used in environmental sequencing surveys.
Sulfolobaceae are a family of the Sulfolobales belonging to the domain Archaea. The family consists of several genera adapted to survive environmental niches with extreme temperature and low pH conditions.
In taxonomy, the Thermoproteaceae are a family of the Thermoproteales.
In taxonomy, Vulcanisaeta is a genus of the Thermoproteaceae.
Sulfurisphaera is a genus of the Sulfolobaceae.
In taxonomy, Thermococcus is a genus of thermophilic Archaea in the family the Thermococcaceae.
Acidilobus is a genus of archaea in the family Acidilobaceae.
In taxonomy, Staphylothermus is a genus of the Desulfurococcaceae.[1]
Caldococcus is a genus of Archaea in the order Desulfurococcales.
Thermococcus celer is a Gram-negative, spherical-shaped archaeon of the genus Thermococcus. The discovery of T. celer played an important role in rerooting the tree of life when T. celer was found to be more closely related to methanogenic Archaea than to other phenotypically similar thermophilic species. T. celer was the first archaeon discovered to house a circularized genome. Several type strains of T. celer have been identified: Vu13, ATCC 35543, and DSM 2476.
Pyrobaculum aerophilum is a single-celled microorganism in the genus Pyrobaculum. The first Pyrobaculum species to be sequenced was P. aerophilum. It is a rod-shaped hyperthermophilic archaeum first isolated from a boiling marine water hole at Maronti Beach, Ischia. It forms characteristic terminal spherical bodies like Thermoproteus and Pyrobaculum. Its type strain is IM2; DSM 7523). Its optimum temperature for growth is around boiling point for water. Its optimum pH for growth is 7.0. Sulfur was found to inhibit its growth.
Thermoplasma volcanium is a moderate thermoacidophilic archaea isolated from acidic hydrothermal vents and solfatara fields. It contains no cell wall and is motile. It is a facultative anaerobic chemoorganoheterotroph. No previous phylogenetic classifications have been made for this organism. Thermoplasma volcanium reproduces asexually via binary fission and is nonpathogenic.
Arsenate-reducing bacteria are bacteria which reduce arsenates. Arsenate-reducing bacteria are ubiquitous in arsenic-contaminated groundwater (aqueous environment). Arsenates are salts or esters of arsenic acid (H3AsO4), consisting of the ion AsO43−. They are moderate oxidizers that can be reduced to arsenites and to arsine. Arsenate can serve as a respiratory electron acceptor for oxidation of organic substrates and H2S or H2. Arsenates occur naturally in minerals such as adamite, alarsite, legrandite, and erythrite, and as hydrated or anhydrous arsenates. Arsenates are similar to phosphates since arsenic (As) and phosphorus (P) occur in group 15 (or VA) of the periodic table. Unlike phosphates, arsenates are not readily lost from minerals due to weathering. They are the predominant form of inorganic arsenic in aqueous aerobic environments. On the other hand, arsenite is more common in anaerobic environments, more mobile, and more toxic than arsenate. Arsenite is 25–60 times more toxic and more mobile than arsenate under most environmental conditions. Arsenate can lead to poisoning, since it can replace inorganic phosphate in the glyceraldehyde-3-phosphate --> 1,3-biphosphoglycerate step of glycolysis, producing 1-arseno-3-phosphoglycerate instead. Although glycolysis continues, 1 ATP molecule is lost. Thus, arsenate is toxic due to its ability to uncouple glycolysis. Arsenate can also inhibit pyruvate conversion into acetyl-CoA, thereby blocking the TCA cycle, resulting in additional loss of ATP.
Acidilobus saccharovorans is a thermoacidophilic species of anaerobic archaea. The species was originally described in 2009 after being isolated from hot springs in Kamchatka.
TACK is a group of archaea, its name an acronym for Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota, the first groups discovered. They are found in different environments ranging from acidophilic thermophiles to mesophiles and psychrophiles and with different types of metabolism, predominantly anaerobic and chemosynthetic. TACK is a clade that is sister to the Asgard branch that gave rise to the eukaryotes. It has been proposed that the TACK clade be classified as Crenarchaeota and that the traditional "Crenarchaeota" (Thermoproteota) be classified as a class called "Sulfolobia", along with the other phyla with class rank or order.